# Tube rolling thread | UltraSonic Studios



## OctavianH (Nov 12, 2022)

*Tube rolling thread | UItraSonic Studios
(for amplifiers with tube rolling add-on and different custom features)*




(Infinity with tube rolling add-on | UltraSonic Studios, picture taken from here, all credits to @SonicTrance, specs at point 1) below)

*Version:*
12.11.2022 - 2.0 - added the Push-Pull version of Odyssey
15.06.2022 - 1.9 - added a remark about the black version of Odyssey and Finissey (Odyssey and Infinity combination)
17.03.2022 - 1.8 - removed Tube Compatibility Guide since no other manual grid bias amps were built and can be misleading
22.10.2021 - 1.7 - added some useful links in the Resources section (including a russian equivalence table)
05.04.2021 - 1.6 - updated Eternity specs and tube rolling procedure
14.03.2021 - 1.5 - updated the Tube Compatibility Guide with the values from here
11.02.2021 - 1.4 - added Odyssey classic SET amplifier
07.02.2021 - 1.3 - added Tube Compatibility Guide section
02.02.2021 - 1.2 - added Resources section
28.01.2021 - 1.1 - added methods to calculate grid bias value (preliminary)
26.01.2021 - 1.0 - initial release

*Introduction*

This thread is supporting the *Tube Rolling add-on* available on Infinity and Eternity tube amplifiers, as an additional resource for the original UltraSonic Studios thread. The purpose of this one is to extend the discussions on the tube amplifiers built by @SonicTrance on behalf of UltraSonic Studios without mixing them with the original builder's thread where the focus is the stock version of the amplifiers. Besides Infinity and Eternity this thread will support also Odyssey which will be a classic SET amplifier. The following tube rolling principle will not be valid for Odyssey, which will have automatic cathode bias.

*General principle of the tube rolling add-on*

When UltraSonic Studios released Infinity, following the Oblivion and Citadel builds described in the builder thread, more and more people started to ask about specific custom builds on other tube types than the ones used in the stock version. The philosophy of UltraSonic Studios is to always use cheap tubes in a design which will provide sound quality above the price. However, several users on these forums, including myself, owning already several tube types wanted to use them in the upcoming amplifiers. This is how the tube rolling add-on appeared.

The tube rolling principle is based on variable Grid bias voltage (multiturn trimmers) for each stage (input and output) of the amplifier. By setting a specific negative voltage for each stage, you are allowing the amplifier to accept different tube types with different electrical parameters. In order to allow the setting of these voltages, the builder will add measuring points (banana jacks) on the top plate of the amplifier where, using a digital multimeter, the owner will be able to measure the voltage for the input and output stage and adjust it to match expected tube type bias. There will be three points for both stages: two positive (one for input and one for output) and one common (ground). Besides the measuring points, the amplifiers will have mA meters to measure the current flowing in each tube or stage (depending on design you might have a common mA meter for both input/output tubes or a meter per each tube, these details have to be clarified with the builder). In case you will have only one meter/stage you will be able to opt for a switch to commute between channels and see both currents on the same meter based on the selected channel. These meters will provide complete control and verification of the bias is setting and also provide information about tube aging (here we will update when more info is available). More details about this feature in the following post, the first part of the Q & A session with the builder.

*Disclaimer*

I am not the owner of all this information, this belongs to UltraSonic Studios and the people who contributed. I am just gathering and updating the first posts of the thread and I will always post the source and give credits to the owner of the information. When this would be not possible I will make a remark about it. Some of the information presented belongs to me and has no other source presented.
I will also update periodically the first 3 posts, reserved for Summary, Links and Important Information which have to be easily found by others. I will also update the specs of the amplifiers, add explanations for add-ons and everything needed. For any suggestion or mistake feel free to write me and I will do my best to keep this accurate and up to date.

Below there are some examples of custom amplifiers which incorporate the Tube Rolling Add-on or even a classic SET amplifier with auto-bias. When more amplifiers will be built and if these will incorporate new features, we will add them here. If you are thinking to order a custom amplifier based on Infinity or Eternity, you can take these examples as baseline for your own build. From this point onwards, for more customizations or questions you can, of course, directly contact the builder.

*1) Infinity with custom add-ons* (pictures here)





*Tube sockets:*
- 2 output sockets designed around the 6L6 / EL34 / KT66 series
- 3 input tubes so I can do either one 6SN7 or two 6J5 or others with adapters.

For the EL11, MHLD6 and EL32 adapters I had them designed around a single socket. The best adapter is none but since those need one anyway so I guess there's no point of going with two single adapters instead.

The left knob is to select the speaker and pre-amp outputs and the right knob is the impedance switch.
The speaker/pre-amp switch has three positions: OFF/speaker/pre-amp
The impedance switch has also three positions: OFF/low/high

The amp has three different heater windings. Rather than paralleling all of them I kept them separate like this:
Output tubes: 5.4A
6J5 sockets: 3.8A
6SN7 socket: 2.5A

*Other features and add-ons:*
* 4-pin XLR headphone output
* RCA pre amp output on rear
* Speaker output on rear
* Dummy RCA jack: (connected to ground)
_This was my idea allowing me to use "RCA tuning stick" for increased dampening_
* Two small bias adjustment knobs on top plate for grid biases but not plate voltage along with 3 ports for an external DMM volt-meter
* Headphone / speaker switch: one position for headphones and line-out simultaneously, and one position for only speakers
* Impedance switch: 3 Positions: headphone off, low, high
* 4 mA meters (two large on front, two smaller on top plate)
_We thought one for each tube is better to specifically detect which tube is faulty rather than one per dual set_

Tomas had replaced the trimmer_(potentiometer)_+voltmeter concept of Infinity with trimmer + dip slot; now the user instead inserts an external voltmeter when adjusting the bias which is necessary to improve performance with tube rolling and prevent damage to the transformers. He explains this was done out of necessity for a no-compromise design and using a digital meter is better to give more accurate reading anyway, and I'm trusting his judgement.

*2) Eternity with custom add-ons *(pictures here)





Eternity is the smaller brother of Infinity, a low power version built in a smaller chasis (340x305x180mm). It is a headphone only amplifier which will have also the Tube Rolling Add-ons and other specifically custom features asked by the owner. If needed, speaker outputs can be added to this model, see below more about power output and limitations in this specific case.

*Tube sockets:*
- 1 x 6SN7 as input OR
- 2 x 6J5 as input (wired to allow 6N7G with triodes in parallel)
- 2 x 6V6 as output (allows EL34 natively)

*Compatible tubes:*
- Input: 6SN7, 6F8G, 6C8G (barely), 6J5/6C5, 6N7G (without adapter), 6N1P, C3G, EL3N again most likely a lot more.
- Output: KT66, KT77, KT88, KT120, KT150, 6550, 7581A, 6V6, EL3N, EL32, EL34, EL81, EL36, EL38 and most likely a lot more.

*Other features and add-ons:*
- Khozmo attenuator (48 steps stepped attenuator)
- Redesign around different tubes (6V6/6J5/6SN7)
- Bias adjustments (tube rolling add-on, see 1) for details)
- VU meters (a light to guide you into darkness, just for appearance, will have an on/off switch to disable it when not needed)
- Impedance switch (low/high gain mode)
- Current through tube switch/channel (mA meters will show left/right based on setting)
- Input socket switch (a switch to choose between 2x6J5 or 1x6SN7, allows you to populate all 3 input sockets at the same time)
- Fixed bias switches (a switch to turn off tube rolling, when ON the amplifier uses the stock bias settings of 6J5 or 6SN7/KT66)
- EIZZ Teflon sockets (tube rollers shield against wearing)
- XLR inputs (for convenience, the amplifier is SE)
- 4-pin XLR output (for convenience, the amplifier is SE)

If needed, additional to what is mentioned above, speaker outputs can be added (3W into 8 ohms is enough for high efficiency speakers). However, keep in mind that the Speaker/Pre-amp switch will replace the Input switch. Therefore, the conclusion is that not all add-ons can be ordered at the same time and every configuration has to be discussed with the builder.

To have an idea about the power output, below is a table for Eternity:





Besides the above described version of Eternity, there is another version, in a different chassis, with dual 6.3V/12.6V independent heater circuits for inputs and outputs, allowing the use of, for example GU-50, 12L6GT or 12V6GT as outputs and 12SXGT or FDD20 as inputs. I have not created a separate section for this amplifier since it derives from Eternity. This version will have a special wiring on 6j5 sockets to be able to use dual 6N7G and also anode caps for the 6V6 sockets (usable for EL38, EL39).





In the end, just to have an idea about the difference in size, Eternity with its bigger brother, Infinity (this one with stock tubes):





*3) Odyssey with custom add-ons *(pictures here)

*

*

Odyssey will be a classic old school tube kind of design. It will be SET, ie transformer coupled and using good specialised transformers with taps of 8 and 50 ohms for headphones and speakers, Mundorf S/G/O caps and maybe Vishay resistors.

*Tube sockets:*
- 2 x EL11 (as strapped triodes)
- 1 x 6SL7 (as double triodes) - in this same socket, 6SN7 can also be use. 12au7, 12at7 and 12ax7 can also be use via adapters.
- 2 x KT88, KT77, KT66, KT120, KT150, EL34, EL12 spez via adapters, 6L6GC, 6550, 5881, 807 via adapters.

*Tube rectifiers:*
- 1 x GZ34 which has a very low voltage drop. Any other rectifiers with a higher voltage drop can be use... that includes GEC U52, Cossor 53ku, GZ37, etc.

*Other features and add-ons:*
- Sowter transformers
- Speaker out
- XLR inputs (in addition to RCA in)
- 4-pin XLR out (in addition to 1/4 inch out)
- Impedance switch
- Mundorf coupling caps
- Yamamoto sockets

There is one power transformer and 2 x output transformers. A choke is also use. The transformers will have winding taps of 8 and 50 ohms. That should cover speakers and headphones. Additionally depending on price, will add another 2 windings - 100 and 300 ohms. That should cover most headphone range and I'm not using iems on this amp that is for sure. The 3 transformers are mounted to the back of the top chassis plate and they will be naked because naked is good. The choke is installed inside the chassis and will not be seen. In front of the centre power transformer is the GZ34 socket. Flanking the rectifier are the KT88 sockets. In front of the GZ34 socket is the 6SL7 socket. Flanking the 6SL7 socket are the two EL11 sockets. It will be symmetrical in appearance.

I've decided to go with the silver chassis used in Citadel for Odyssey because it will blend in very well with the grey colour of the Telefunken EL11 and EL12 spez tubes. Also the silver / grey Sowter's transformers exposed naked in the silver chassis will be just perfect.

There is also a black version of Odyssey, with an audio-gd theme which can be seen here.





And also a Push-Pull version, as can be seen here:





This latest incarnation of Odyssey has some very special features like adjustable operating point and support external power supply for heaters besides triode/ultralinear modes. More details in the above mentioned link.

At the moment these 3 basic types are the only ones we know about. Based on these, more and more amplifiers were built, one very interesting build being Finyssey which combines Odyssey and Infinity. We did not add it as a separate section because it is a combination of 2 already existing types. We have not added Telemachus 300B model since we are not sure about tube rolling potential and how it will fit in the context of this thread. When more amplifier types will be available, if these will have something new, we will add them and also reorganize the information in a readable form. More to come, so bring your popcorn, take your beer, put your most loved headphones close and read this periodically.


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## OctavianH (Oct 22, 2021)

I had long discussions with @SonicTrance when defining the requirements for my custom Eternity amplifier. Some of the discussions are very useful for other people who think to order or want to understand more about these custom versions which support tube rolling. I saved the discussions and I am trying to present them here in a easy readable form. I will structure this as a Q & A session. All credits go to him, I am just a humble storyteller. I will also update this post with other information I will see on the thread, mentioning, as always, the source and owner.

*Q & A regarding UltraSonic amplifiers, tube rolling and other add-ons 
available on Infinity and Eternity*​*First of all, how do I tube roll?*

Equipment and skills needed:
- digital voltmeter
- screwdriver
- minimum electrical skills to be able to measure a voltage

*Tube rolling principle:*

Each amplifier will have at least 1 x mA meter to measure the current into each stage (per stage or tube depending on the design). There will be measuring points on every stage where via a digital multimeter the user will be able to measure the grid bias voltage and adjust it for each specific tube type. More on this will be presented later, with pictures. At the moment we can say that we will measure a voltage, receive a table from Tomas with grid bias voltages and then adjust the input and output stages accordingly.

Be warned before starting that *the grid bias values for each amplifier are different*. This means *DO NOT* set a voltage for a specific tube type on Eternity if you read it from someone on Infinity. This might damage the amplifier! Always set proper voltages on each stage, and carefully check if those are the correct ones for your own amplifier. More than this, the same tube type can have not only different bias values on different amplifiers but also depending on the stage used. Ex. EL3N on output will not have the same value to set as on intput. Since each amplifier can have different operating points, everything has to be checked for each build in particular.

*Grid bias adjustment:*

Before starting to make any tube rolling or grid bias adjustment please take your time to study the procedures which need to be followed. These need to be followed carefully in order to ensure proper operation of your amplifier and have been detailed and supervised by the builder himself. In short, when exchanging tubes (with or without grid bias adjustment) some waiting time for the circuit to "settle" is needed. What to do is described at the points A) and B) below. But before going there let's first understand clearly how the grid bias is adjusted. The steps below are corresponding to the step "adjust bias" from the procedure at point B), when adjusting grid bias you need to follow the whole procedure presented there.

Steps for bias adjustment:
- set the digital voltmeter scope to 100V DC (or more)
- connect the digital voltmeter probes to the measuring points on the amplifier (marked red and black -  see photo below)
- set the voltage to the desired value via the multiturn trimmers (see photo below) on the top plate *
- when turning clockwise the multiturn trimmer the current in the tube increases, meaning that on the digital voltmeter the negative value will decrease
- follow the display on the digital voltmeter to reach the desired negative voltage




_(example, these can have different positions on different builds)

* tolerance for currents in each stage: Input stage: 3mA to 5mA, Output stage: 15mA - 24mA (fuse will blow @ 25mA)_

*During operation, wait 5 minutes after you power OFF the amplifier before powering ON again, regardless of the reason. 
 (tube exchange, grid bias change, input switch from single/double triode)*​
*A) Procedure to exchange the tubes without adjusting the bias*

- power OFF
- wait 5 min **
- remove the tubes
- insert new tubes
- power ON

*B) Procedure to exchange the tubes when bias adjustment is needed*

- power OFF
- wait 5 min **
- remove the tubes ***
- power ON
- adjust bias ****
- power OFF
- wait 5 min **
- insert new tubes
- power ON

_**  to let the power supply caps drain before inserting the tubes. 
*** only for the stage you are adjusting, if you adjust only input state, you need to remove only the tubes on input stage
****  a good practice is to start with a slightly higher negative voltage (i.e. -10.5V instead of -10V) and then lower it, ensuring that the tube does not draw more current than is allowed by the circuitry_

*Now, when I learned that, what should be the Bias adjustment precision?*

On output tubes maybe +-one volt is ok. It's more important on input tubes.
If the bias voltage is too low, the tube will draw excessive current and some components inside the amp will fail.
I should say the tube draws more current the closer you get to 0V. The further below ground you are the less current will go through the tube.

*UltraSonic amplifiers in general, will I be able to adjust the sound via tube rolling in this specific circuit and design?*

These are not old school style tube amps where the tubes are resistor loaded and have a load line which goes into the non-linear region of the tubes. The tubes are always working in their linear region thanks to the gyrator plate loads. Other design choises makes these amps have fast transient response and transparency. But, all amplification is done by the tubes! That's what tubes do best, amplify voltage. MOSFETs supply current together with the output tubes. That way all components do what they do best! There's no SS sound at all from any of these amps.
My amps don't have "driver tubes", they have "input tubes". The input tube don't drive anything. I have source followers (grid drivers) that drives the output tube grid. So the input tubes function is only for voltage amplification. The output tubes however are working together with it's plate load (gyrator) to supply current to the load. Oblivion has some more tube flavor than Citadel and the upcoming Infinity will have even more. The output stages in Oblivion and Citadel are LTP stages with a CCS tail.
In classic designs the input signal goes to the grid of the driver, then the anode goes to the grid of the output tube and so on. It's the same in Eternity also. The difference is that we have source followers in between that drives the output tube grid. You can read about the grid drivers on the "amps" page on my website.
All tube rolling will have effect on the sound sig. In a classic amp the input tube "drives" the output tube. So one has to account for things like rp and other characteristics of the tube. Those things are only important in the output tubes in my amps. But, the input tube will still affect the sound!

*How important are electrically matched pairs (input/output)?*

In Infinity you would, technically, benefit from electrically matched pairs. More so than in my balanced amps. That's because in the balanced amps there's a CCS that sets the current. That current is always firm. One tube can still draw more current than the other (in the same channel) but the total current remains the same.
Infinity is single ended and grid biased. That means that for two tubes to draw same amount of current at a fixed bias point they need to be electrically matched. With that said, for you to notice any channel imbalance the tubes needs to be very mismatched.

*Do these amplifiers have Soft Start?*

My amps doesn't have soft start as it's not needed. In old school amps the tubes are exposed to the full B+ voltage on startup. I use a regulated B+ supply and a firm voltage reference to the plate of the tubes. They'll never see one volt above what they're suppose to.

*How important is the heater current on input/output tubes when deciding to use a specific tube type?*

Regarding heater current that doesn't matter at all in regards to input or output tube. An input tube is high gain and low current (plate current), output tube is low gain and high plate current. There's a bit more to it but that's basically it. Heater current doesn't matter at all. The lower the better.

*What is the Max load allowed on Eternity?* (will be updated also for Infinity when I will have this information)

The heater winding is speced at 14 A, so not really a concern.

*Is there any difference between XLR inputs on Infinity or Eternity vs Citadel?*

If I put XLR inputs on Eternity or Infinity it'll only be for convenience. It'll still be SE, no different than an RCA cable of the same quality. Citadel is balanced from end to end. In that amp you fully utilize the 2 phases per channel a balanced signal has.

*What transformers are used in the UltraSonic amplifiers?*

I use standard Hammond output transformers and Toroidy power transformers. In Eternity, the Hammonds are all you need as the output is parafeed and they're driven from low impedance.

*Why manual grid bias instead of auto bias on Eternity/Infinity?* (source here)

Less capacitors in the signal path using grid bias. Even if I'd use cathode bias in Infinity/Eternity you couldn't just roll tubes without adjustment. The gyrator is still set at a specific current.

*Is there any headphone impedance limitation or recommended range?*

It'll drive any impedance but will have highest power output into low impedance than less and less the higher the impedance (ohms law). Most high impedance headphones doesn't need much power to drive and they present virtually no load to the amp. Impedance matching is important for power but not necessary for SQ. Low impedance output will drive most any headphones.

*Does it make sense to do crossmatching on tubes (for a dual triode with unmatched section using a stronger output tube to compensate)?*

I'd not recommend compensating a weak input tube with a strong output tube. The circuit is most happy with good strong tubes and that goes for all amps. But, especially Infinity and Eternity.

*What are the VU meters measuring on Eternity?*

The VU meters measure the output signal. So the more you turn up the volume the more movement on the meters.

*What is the Impedance switch effect (Low-Z vs High-Z)?*

What the impedance switch does is changing the turns ratio of the OT to get higher output impedance. This creates more distortion but also more power into high impedance headphones.

*Resources:*

Radiomuseum.org (thanks to @hpamdr)

Frank's electron Tube Data sheets (thanks to @hpamdr)

tubebooks.org (thanks to @triod750)

4Tubes - Tube Data Sheets

JACMusic - The KT88 / KT66 /6550 Directory

TDSL Personal Edition

The Reference 6J5 Thread (L63, 6C5, 12J5, 6P5, etc.)

The Reference Pentode and Beam Tetrode Thread EL34, KT66, KT77, KT88, EL11, EL12, EL3N, EL35, EL37, 6550, 6L6, EL51, EL39, 4654, 4699, KT63, KT61, 6V6, etc

Russian Vacuum tubes equivalence table / Таблица аналогов ламп

*Educational videos:*


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## OctavianH (Mar 17, 2022)

*Procedure to determine the Grid Bias Voltage for Output stages*​
*Before you start:*

Be sure to check post 1) and 2) and understand the tube rolling principle.

*Be aware that wrong operation might damage your amplifier. 
 DO IT AT YOUR OWN RISK. 
Nobody here takes any responsibility for any damage.*​
*Introduction:*

The builder will provide operating points of each amplifier to the owner. He will also provide values for most common tube types in a table and those should be used if they are available. However, several users tried to present a way to calculate these values and I tried to summarize and present them here. The owners of the informations and credits are found below on the thread.

*Needed information for calculation:*

- operating points of the amplifier for each stage (Vplate / Iplate)

*Method 1 (recommended) - Use the Tube Datasheets and Triode connection curves

Steps:*

1. Find the appropriate datasheet of the tube you want to use
2. Search inside for the Triode Connection curves as a graph of Vplate (V) vs Iplate (mA)
3. Carefully check the operating points of your stage (might differ on each build, please check with the builder) as a pair of Vplate (V) and Iplate (mA) values
4. Intersect on the graph the Vplate (= your operating stage voltate) with Iplate (= your operating stage current) and obtain a point on the graph
5. Estimate based on the graph the Vgrid (several fixed values are presented as an exponential function).

*Example 1: 6V6 as Triode in the Output Stage.*

1. The datasheet of a 6V6 is this one:

_Hint: A good place to search for datasheets is The Valve Museum and the fastest way to find the tube you need is a simple Google Search:_





For 6V6 we have this one. At page 4 we have the Triode Connection graph.
If we consider our operating points of the output stage as Vplate = 200V and Iplate = 20mA the intersection of these values on the graph is close to Vgrid = -15V:





_Hint: Always try to round to a bigger negative value (but not more than 1V), ensuring a lower current than the one you want to set and later adjust it. In this way you are sure not to damage your amplifier internal circuitry._

*Method 2 - Use the calculator*

There is an output stage calculator available here.

*Steps:*

1. Choose Operation Mode = Triode
2. Choose Vplate (= your operating stage voltate)
3. Choose Iplate (= your operating stage current)
4. Calculate the Grid Bias Voltage

*Example 1: 6V6 as Triode in the Output Stage.*

Applying the settings presented above for the same operating point described in the previous example we obtain the following value:





The recommended value using the calculator is smaller than the one from the tube graphs (-13.29V vs 14.5V) and was most probably determined by measured values of existing tubes.

Builder's remarks on these 2 methods and why graphs are better is here.

Builder's example of grid calculation for Infinity here.

*Tube Compatibility Guide*​

TBD

*Tube rolling combos
(impressions, pictures, links)*​
TBD

*Clarification needed:*

TBD


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## m-i-c-k-e-y

Thank you for starting this  . Now I can browse thru at peace at the other thread .


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## SonicTrance

@OctavianH 
Great posts!



OctavianH said:


> 3. Stop the amplifier *wait 5 min* and insert the tubes in the sockets


Fixed it for you! That's to let the power supply caps drain before inserting the tubes.


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## OctavianH

SonicTrance said:


> Fixed it for you! That's to let the power supply caps drain before inserting the tubes.



Updated. I have just tried to gather the information in the other thread and structure it. It is just the begninning but I think it is already enough for someone to have an overview and to be able to understand what you are building with this new add-on.


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## SonicTrance

OctavianH said:


> Note: You cannot use all 3 inputs (single and double triodes) at the same time, however all tubes will glow because the one not selected as input will not have the plate and grid connected.


This is only the case if you get an input tube selector switch. If no switch you can only have either the 6J5's or the 6SN7 socket populated at the same time.


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## OctavianH

SonicTrance said:


> This is only the case if you get an input tube selector switch. If no switch you can only have either the 6J5's or the 6SN7 socket populated at the same time.



Ok, I will update it. The only 2 builds I know of are having 3 inputs but you are right, other builds will come which might be different.


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## SonicTrance

OctavianH said:


> Ok, I will update it. The only 2 builds I know of are having 3 inputs but you are right, other builds will come which might be different.


There might have been some misunderstanding. Levi's Infinity will not have the input selector like yours. So he can't have all input sockets populated at the same time.


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## OctavianH

SonicTrance said:


> There might have been some misunderstanding. Levi's Infinity will not have the input selector like yours. So he can't have all input sockets populated at the same time.



Ok, I removed that part completely as it creates confusion. I removed also the question related to tube wear when not selected. These remain specific parts which we remove.


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## OctavianH (Jan 26, 2021)

I started to be very curious about EL39 today, after what I have read on the original thread here. I do not own any EL39 in my collection or adapters for it but as far as I know it is the predecessor of EL34. Now, EL34 has a relaxed sound and great bass, which makes me think about KT77. I have a pair of KT77 and now I wonder how close are these to EL39. Is anyone here who tried on the same amplifier EL34/KT77 and EL39 and can tell use if those were close?
I searched for a clear datasheet and could not find about these.


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## hpamdr

OctavianH said:


> I started to be very curious about EL39 today, after what I have read on the original thread here. I do not own any EL39 in my collection or adapters for it but as far as I know it is the predecessor of EL34. Now, EL34 has a relaxed sound and great bass, which makes me think about KT77. I have a pair of KT77 and now I wonder how close are these to EL39. Is anyone here who tried on the same amplifier EL45/KT77 and EL39 and can tell use if those were close?
> I searched for a clear datasheet and could not find about these.


 The EL39 was designed as an Audio tube for amplifier in movie theater being powerfull and reliable the RFT have special construction with anode on ceramic and gold plated grids The grids are not aligned and this make the tube in pentode mode a bit less efficient than EL34. Once strapped as triode, you get the magic    
The closest datasheet you can find are for the 4654 / EL50 tubes. [I got the info from Jean Luc Benoist, he built some version of U.F.O amp with it and still use the tube in the new COVID amplifier... ]


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## OctavianH (Jan 26, 2021)

I want to try them but I think to postpone this until I will try what I have. This means EL32 and EL38. I have to admit that I prefer to use "native" tubes instead of ones with adapters. For me EL32 is a very special tube, very good on vocals, piano or orchestral music. The problem comes when electric guitar comes into play and since I listen 99% to rock music I guess you realize how often that happens. Until now, my all time favourite for guitars is KT66, but with Eternity I am not sure if KT66 will sound the same as I know it. So the question remains if what I love at KT66 is the proper biased sound or maybe the distorted one. We will see more about this in the future.

In short terms:
- I do not like tubes with top cap, however I like a lot how 6F8G or EL32 sounds
- I do not like the EL3N base and hate the adapters for it (a few broke already)
- I do not like also the EL11 base, even if it is much better than EL3N

In my ideal tube world all tubes are octals, work natively, are cheap and sound perfect. OK, time to wake up now. 

Later edit:
I think this adapter works on Eternity/Infinity for EL39 as output.


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## hpamdr

OctavianH said:


> I want to try them but I think to postpone this until I
> In short terms:
> - I do not like tubes with top cap, however I like a lot how 6F8G or EL32 sounds
> - I do not like the EL3N base and hate the adapters for it (a few broke already)
> ...


Yes this adapter will work, another solution can be to have removable anode cap on the amp to use el39, el36... 
About adapter, it would be better if you can build them or ask to a better builder than ebay.


----------



## OctavianH (Jan 28, 2021)

hpamdr said:


> Yes this adapter will work, another solution can be to have removable anode cap on the amp to use el39, el36...
> About adapter, it would be better if you can build them or ask to a better builder than ebay.



I never took too seriously to build my own adapters because I rarely need to make a new one and to buy spare parts for 2-3 adapters never made sense for me. Another reason is that I have 2 left hands and I am not sure if the time and effort makes sense. However I plan to try to make myself some interconnects, because the prices exploded in that area, so maybe I will also try to make myself some adapters. If not there are several sources where you can obtain better adapters than Ebay.

Regarding EL39 the information is not very good, but I found a Philips 4654K datasheet:





And from this one I deduced the pinout:





Now, the datasheet does not have any triode connection curves so it is not very clear for me what grid bias needs.


----------



## hpamdr

OctavianH said:


> Now, the datasheet does not have any triode connection curves so it is not very clear for me what grid bias needs.


Your schema seems to be OK, as you can see pin 3 is not used in EL39 and could be used to connect anode cap. in fairly simple EL39/EL34 adapter. 
As you can see EL32 is a different beast.

EL38 is almost the same as EL39 just switch pin 1 and 6 (or connect together if p1 is not on the ground on the amplifier to have EL39/EL38 adapter)


About curves, this is mostly the case for many pentode, Tomas will probably get a pair of el39 from DL box of tube even if the concern is for infinity, I'm pretty sure i will be able to extrapolate bias grid voltage for eternity. If not the best would be to measure it once strapped with a curve tracer (Utracer3++ or 6, etracer ...) os ask if someone have it in one of the user forum...


----------



## OctavianH

hpamdr said:


> Your schema seems to be OK, as you can see pin 3 is not used in EL39 and could be used to connect anode cap. in fairly simple EL39/EL34 adapter.
> As you can see EL32 is a different beast.
> 
> EL38 is almost the same as EL39 just switch pin 1 and 6 (or connect together if p1 is not on the ground on the amplifier to have EL39/EL38 adapter)
> ...



I discussed with Tomas in the context of EL34 in the output socket without adapter and he told me:



> If you wanna use EL34 which has g3 on pin one I need to connect pin 1 to pin 8, cathode, which in turn will be grounded.



So Pin 1 is connected to Pin 8 and grounded. But this might be the situation in my amplifier, I do not know how others will be wired but I think a standard would be useful otherwise our advices here might not be accurate for different users of the same model.

For grid bias I found a calculator:
https://www.vtadiy.com/loadline-calculators/power-stage-calculator/

From what I know now (might change, so I am not sure if it is final, input stage will have 180V/4mA and output stage 200V/20mA). If I want to use 6V6 in output stage I set Operating Mode = Triode, Then 200V and 20mA and the Grid Bias voltage is around -13.29V. I'll set it with the Digital Multimeter to -14.5V to be sure current is lower than 20mA then just adjust. 
(I never tried that, I just plan how I would do it, so any advice is welcomed)


----------



## hpamdr

I think that those calculation are made with spice model of selected tube.. _(I suggest to add it on post 3 of the tread)_
About strapping a Pentode as Triode, the wiring is the one on page 23 of this reference presentation.


pin for EL34WirringTriode*1 + 8*K + G3   (it is even done in some tube)  K   (cathode)*5*G1G   (grid)*3* +_ 4 (with resistor)_A + G2 using a 100 Ohm ResistorA    (anode)2 - 7heating heating
 @SonicTrance
Pin 6 is not used in EL34 but is used as g3 on some tube. Does wiring to pin 1 or 8 make any sense ?


----------



## OctavianH

I will add it after at least one of us will try it and test it. I know about 2 ways of determining the Grid Voltage (this one above and one Tomas showed me, with the Triode Curves).
In this method, we obtain a value of -13.29V for our Grid bias voltage for Vplate = 200V and Aplate = 20mA (as we prezume we will have in the amplifier on output stage).
But using the datasheet and triode curves from them we deduce a value close below -15V (by intersecting the 200V with 20mA we are close to -15V for grid bias).




Since we have more than 1.5V difference between the calculator and a datasheet, I think we need to decide what tolerance we have, how it is the best way to do and later decide which values are appropriate to our circuit. So I would say we need to test this in the first amplifier when it is build and see the real situation.
More than this, since tube rolling is a hobby for me, I am not every time carefully watching these graphs so I make stupid things like using the pentode connection graphs or even intersecting wrong.

How I see it:
- we can use the calculator
- we can use graphs
- we can use both and choose medium value 
- we can put a table on post 3 with tube type, Vplate, Aplate and everyone based on its build will know what to choose
- we can put all three ways there and everyone has to do however he/she wants

Because of these things I have not, yet, put anything there. Another reason is that I am not sure about operating points on the final build.


----------



## SonicTrance

hpamdr said:


> @SonicTrance
> Pin 6 is not used in EL34 but is used as g3 on some tube. Does wiring to pin 1 or 8 make any sense ?


It can make sense. But, I usually stay away from wiring unused pins inside the amp. This is because some tubes have internal connections on unused tube pins that can cause issues. 
I can do some more digging on this.


----------



## SonicTrance

OctavianH said:


> But using the datasheet and triode curves from them we deduce a value close below -15V (by intersecting the 200V with 20mA we are close to -15V for grid bias).


This is correct. I'd always look at the triode curves as first option. Granted these were drawn by hand and is not super accurate all the time but it's the best we get apart from a curve tracer.
The actual load line will be flat like that and reach all the way to about -28Vg. So the signal can swing from 0Vg to -28Vg. So, it will swing from 60 - 340V on the B+. Eternity will have a B+ of around 360-370V so there's headroom for that kind of swing. B+ in Infinity is 410V.


----------



## OctavianH

Then we can make a procedure like:
- search for Triode curves IF available -> use that value
- if datasheets are not containing graphs (e.g. EL39) or triode connection ones check the calculator, then add 2V to be sure
- use the table as a guide, for what has already been tested on the thread by someone (keeping in mind to carefully choose your operation points)

We can also make this everyone by itself, but then we loose time to calculate something already tested. The power of this thread are the users. I let you guys choose, then I'll just update the 3rd post with what you will consider the best way. I have to admit I do not have enought experience for this, just learning.


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## OctavianH (Jan 29, 2021)

Regarding EL32, I have 2 quads: Marconi and Mullard. The problem is that the Mullard ones have no logo just:





And on the back something like "1005-I IMXA". It is not clear to me, what are the date codes for these?





PS. I edited post 3 with stuff regarding how to determine grid bias voltage. If something is wrong please let me know to fix it.


----------



## UntilThen

Hi folks, I just pick up a Elekit 8200. So will be rolling KT88, 6L6G, EL34, KT77, KT66, EL12 spez.


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## OctavianH

Interesting. I took a look here. I think I know this one, but from what I knew these were sold unassembled and you had to built it for yourself. A kind of IKEA of tube amps. LOL


----------



## UntilThen

That's the one but I bought a used mint unit from someone cheap and he even throw in some current production KT88 / 6L6GC and 12AU7 tubes. I'm intrigued in this amp because it will give me a taste of these power tubes while waiting to see how your and DL amps will turn out.  

In the process, I will also be buying some additional KT66, KT77, 6550, 807 tubes.... down the rabbit hole I go again....


----------



## OctavianH

Before taking the decision to write Tomas and ask him if he can build me a headphone only amplifier based on 6V6 as outputs and, if possible, 6SN7 as input, because I wanted to use a part of my tube collection on it and see where it goes, I searched several months for tube amplifiers based on these. I looked a lot at WBA Virtus-01, ALO Studio Six, Cayin HA-6A or several Prima Luna models. It seems that even if 6V6 are mostly used in speaker amps, everyone who tried them on headphones had nice words for them. In the end I decided to try a full custom build and Eternity took form. We will see where this will go, I am fully convinced it will be interesting for all of us.


----------



## UntilThen

Well I have owned Studio Six for a year and I know how it sound. I prefer Studio Six over my Glenn OTL amp. Studio Six is a very well build product. Quality of construction is first class. I've several pairs of NOS 6v6gt and 6v6 tubes. Studio Six also use 6sn7 as driver and a GZ34 as rectifier but I did use GEC U52 and Cossor 53ku in it too. Not sure why I sold off Studio Six but it's all part of my audio journey. I move along.


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## OctavianH (Jan 29, 2021)

There are a lot of interesting toys, for example these ones.


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## UntilThen

Lots of interesting gear indeed. Interesting that he talk about Bifrost 2, which I just bought to accompany my Yggdrasil. That Schiit Freya + is something I'm interested in too purely because I've also Mjolnir 2, so a few Schiit gear and it should pair well together.... not that it has to be all Schiit.... pun unintended. 

That LTA Ultralinear amp is very interesting.... similar to SE triode amp with negative feedback. That's what he said.


----------



## DecentLevi

Hey guys, joining a bit late here. Though I'm not lacking in experience, I've got a couple dumb questions trying to better grasp about my upcoming custom Infinity amp. This was meant as a PM to @SonicTrance but I thought I'd post it here so the answers can help others too.



SonicTrance said:


> You can run the output tubes from 40mA up to 60mA. But 50 is the sweet spot.





SonicTrance said:


> after you have adjusted the grid voltage without tubes installed, turned off the amp and waited 5 min, inserted the tubes and power on. You watch the mA meters on the amp as the tubes warm up and start conducting. You can then fine tune the bias point with the trimmers while watching the mA meters so the tubes draw the amount of current we want, which is 4mA for the input and 50 for the output tubes, except for the EL32 which you need to run cooler at 40mA.


Hi Tomas, I've been meaning to get back to you to clarify a few things.

So do you mean that with all the diverse types of tubes I specified (EL34 series stock and others with adapters), the only thing that needs to be adjusted for optimal performance is the grid bias from 40-60mA? I thought I was adjusting the voltage not currernt? And this range should even provide close to the high voltage demands for the EL12 Spez down to the very low current draw of EL32?

For adjusting the bias, here's what I understand. Please correct anything that's wrong.
Turn on the amp without tubes and measure with an external DMM (with its' max voltage set to at least 100v) a voltage for the desired tube to roll in according to the sheet you provide. After turning it on with tubes in, fine tune to make sure the meter on the amp is in the center at around 50mA. This trimmer adjustment changes the grid voltage bias but not the current so the external DMM meter will show the difference of voltage while the mA meter will stay the same... except for extreme adjustments needed like for the EL32 this also subsequently causes the mA meter to fall down to 40 mA.
But then if I fine tune the bias with the voltage trimmers on top, how does this correlate with the current on the mA meters? Also after it's on am I supposed to make sure those needles are in the middle, or that the external DMM doesn't drift to the wrong voltage?

If an old tube were to arc / explode, would having the volume down prevent damage to the headphone drivers? If it happens while listening, does the amp have any circuit that prevents or minimizes such loud boom from reaching the headphones?

For the switches, since mine would have a pre-amp, speaker and headphone connections, mine would have a pre-amp and output impedance switch, but not selector switch, right?

Finally, about the 5-min. thing. What's the shortest amount of time you could still recommend between cool down & then waiting time after voltage adjustment sessions? I'm a bit impulsive or ADD and can't see myself waiting so long consistently, LOL.


----------



## UntilThen

Something tells me I must be nuts to buy a NOS pair of GEC KT66 but I am.


----------



## OctavianH

No, you are not. They are incredible. But before doing that I would suggest to try the new production KT66 and KT88 to be sure which ones you like more. When trying them in Elise I preferred the KT66 but many on the F.A. threads prefer the KT88. And from GEC KT66, the smoked grey glass are warmer and more holographic while clear glass are brighter, cleaner and a little bit more detailed (at least how I see them).


----------



## UntilThen

For my amp, I already have Genalex Gold Lion KT88 and Electro Harmonix 6L6GC. I like the 6L6GC - it's warmer and nice bass. KT88 is more aggressive but very exciting with rock. I'm getting a pair of NOS GEC KT66 and a pair of NOS Philip Miniwatt EL34 double O rings. Both clear unfortunately or fortunately depending on how you look at it. 

There are a lot more tubes I can roll. The tubes will cost more than the amp.


----------



## hpamdr

OctavianH said:


> Before taking the decision to write Tomas and ask him if he can build me a headphone only amplifier based on 6V6 as outputs and, if possible, 6SN7 as input, because I wanted to use a part of my tube collection on it and see where it goes, I searched several months for tube amplifiers based on these. I looked a lot at WBA Virtus-01, ALO Studio Six, Cayin HA-6A or several Prima Luna models. It seems that even if 6V6 are mostly used in speaker amps, everyone who tried them on headphones had nice words for them. In the end I decided to try a full custom build and Eternity took form. We will see where this will go, I am fully convinced it will be interesting for all of us.


 I'm almost in the same position I have a collection of tubes that i want to use but want to get a new amp with different topology (SET) and no rectifier. I auditioned dna starlett/stratus and found the sound really great but wanted a more versatile amp (_not as Glenn OTL_). I was also looking on some DIY tube design and found gyrator concept quite interesting. I do not need a speaker amp as today i still use an heavy SS amplifier for my main loudspeaker system. 
This is why I'm so interested by infinity and then the *eternity with tube rolling options. *I finally jumped in the queue.
I will have to wait a bit after @OctavianH but can benefit from his experience (we are both owner of F.A. amp and T1 headphone)..

I will probably keep my Euforia as i like a lot the sound with gec/mullard 6080 and 5998 and it is for me well built and service is first class (_at least in Europe_).


----------



## UntilThen

Hahaha @hpamdr why did you make the last line font so small.   Congrats on getting in the queue for Eternity. I'm waiting for you guys to tell me the tone. This used mint  Elekit TU-8200 is just so amazing with it's tone. Love the KT88 and 6L6GC on it and the 12AU7. I'm getting the adapters to roll EL12 spez on it.


----------



## UntilThen

Tell me which you prefer - 6L6 GC vs KT88 vs EL34


----------



## hpamdr

OctavianH said:


> No, you are not. They are incredible. But before doing that I would suggest to try the new production KT66 and KT88 to be sure which ones you like more. When trying them in Elise I preferred the KT66 but many on the F.A. threads prefer the KT88. And from GEC KT66, the smoked grey glass are warmer and more holographic while clear glass are brighter, cleaner and a little bit more detailed (at least how I see them).


What i guess is that we cannot really predict from F.A. OTL experiences how the tube will sound in Tomas SET amps..
Anyway IMO on Euphoria KT88 (Genalex G.L ) is a tube able to drive many headphone and bring them to life with dynamic, details and sound-stage. It is a bit bright but a wonderful experience with electric blues, rock and electronic music.  I had some NOS KT88 and sold them to only keep the GL which cost between 50$ and 50£  and are for me very well performing.
I also have a friend who get Cayin HA-6A and love it with same KT88.


----------



## OctavianH

hpamdr said:


> This is why I'm so interested by infinity and then the *eternity with tube rolling options. *I finally jumped in the queue.
> I will have to wait a bit after @OctavianH but can benefit from his experience (we are both owner of F.A. amp and T1 headphone)..



So it seems we will be the first Eternity users. This is great, however I am not very good at reviews or describing what I hear and my musical preferences are different than what others consider "audiophile". I also hate this kind of categorization, I am just a guy who likes beer, music and headphones (in this order, LOL). Even in these conditions, I will do my best to describe to all of you what I hear and let's hope you will not be disappointed. I was also enrolled in the Glenn-OTL queue for 9 months but during this time people on the Euforia thread started to discover the KT66. Later they moved on to KT88 and GU-50 but I remained stuck at KT66. I never heard an electrical guitar sounding more real and better than on the GEC clear glass KT66. So I realized that the Glenn-OTL, being not able to use 6V6 type of tubes, is not maybe what I need, and since the things were progressing slow on the queue I have decided to quit and focus on finding an amplifier which can accomodate 6V6 and, if possible, to be shipped from Europe. And this is how I reached UltraSonic Studios, which I was constantly "monitoring" because Oblivion seemed to me something interesting.


----------



## SonicTrance

DecentLevi said:


> So do you mean that with all the diverse types of tubes I specified (EL34 series stock and others with adapters), the only thing that needs to be adjusted for optimal performance is the grid bias from 40-60mA?


Yes! I'll make it easy for you and say that all output tubes, except for the EL32 @ 40mA, should run @ 50mA.



DecentLevi said:


> I thought I was adjusting the voltage not currernt?


Your are adjusting the negative voltage applied to the grid of the tubes. Which in turn sets the operating point. So when you have adjusted the grid voltage, without tubes, and then fine tune with tubes in place you don't need to watch the grid voltage anymore. Only the current is important in the end. Just watch the panel meters while adjusting.
The thing is that the gyrator plate loads are set to run at a specific current and are not happy otherwise.



DecentLevi said:


> Turn on the amp without tubes and measure with an external DMM (with its' max voltage set to at least 100v) a voltage for the desired tube to roll in according to the sheet you provide. After turning it on with tubes in, fine tune to make sure the meter on the amp is in the center at around 50mA.


Correct! 50mA for the output tubes and 4mA for input tubes.



DecentLevi said:


> This trimmer adjustment changes the grid voltage bias but not the current so the external DMM meter will show the difference of voltage while the mA meter will stay the same...


Not correct! The adjustment changes the grid voltage AND the mA meters. This is a very sensitive adjustment, especially for input tubes! That's why I'll use multiturn trimmers to make it less sensitive.



DecentLevi said:


> Also after it's on am I supposed to make sure those needles are in the middle, or that the external DMM doesn't drift to the wrong voltage?


Once you set it it won't drift. No need to measure anything. Have a look at the mA meters every time you power on the amp just to make sure all is good.



DecentLevi said:


> If an old tube were to arc / explode, would having the volume down prevent damage to the headphone drivers? If it happens while listening, does the amp have any circuit that prevents or minimizes such loud boom from reaching the headphones?


I've never had a tube arc/explode and it would depend what was actually happening inside the tube. I can't guarantee it won't affect the headphones but the output transformers and parafeed capacitor should provide some protection.



DecentLevi said:


> For the switches, since mine would have a pre-amp, speaker and headphone connections, mine would have a pre-amp and output impedance switch, but not selector switch, right?


If by selector switch you mean the "6SN7 switch" that @OctavianH will have, then no. Your amp will have impedance switch and a speaker/pre-amp switch. So you can have either headphones/speaker, headphones/preamp on at the same time. Or just one output active.



DecentLevi said:


> Finally, about the 5-min. thing. What's the shortest amount of time you could still recommend between cool down & then waiting time after voltage adjustment sessions? I'm a bit impulsive or ADD and can't see myself waiting so long consistently, LOL.


You can measure yourself with the DMM set to at least 300VDC. Put black probe in black banana jack and red probe in pin 3 of the output tube socket. You count the pins counter clockwise from the guidepin. When the voltage is down to a couple of volts you're fine.

Hope that helps.


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## OctavianH (Jan 30, 2021)

SonicTrance said:


> Yes! I'll make it easy for you and say that all output tubes, except for the EL32 @ 40mA, should run @ 50mA.



This is valid also for Eternity?



SonicTrance said:


> You can measure yourself with the DMM set to at least 300VDC. Put black probe in black banana jack and red probe in pin 3 of the output tube socket. You count the pins counter clockwise from the guidepin. When the voltage is down to a couple of volts you're fine.



I have a rule:
- count the pins as you look to the socket of the amplifier counter clockwise starting from the guiding pin
- count the pins as you look to a tube base clockwise starting from the guiding pin (what you see on datasheets)
Confusing stuff, this is why I prefer others to make adapters because I am sure I'll do something wrong.


----------



## hpamdr

OctavianH said:


> have a rule:
> - count the pins as you look to the socket of the amplifier counter clockwise starting from the guiding pin
> - count the pins as you look to a tube base clockwise starting from the guiding pin
> Confusing stuff, this is why I prefer others to make adapters because I am sure I'll do something wrong.



I  have the yellow jacket adapter drawing as a reference printed to have top view socket and bottom view tube.
When you see pin it is clockwise when you see hole it is anti-clockwise.
Also if you want extensive info on socket you can use this radio museum documentation.


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## OctavianH (Jan 30, 2021)

There are many invaluable resources, one of them is this one:
http://www.4tubes.com/navigation/index-datasheets.html

A very nice article related to KT88 but not only those is this one:
http://www.jacmusic.com/KT88/kt88.htm

I think a section with links would be useful in the first posts.


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## SonicTrance

OctavianH said:


> This is valid also for Eternity?


Eternity will run all output tubes @ 20mA. Input stage will run @ 4mA just as Infinity.


----------



## UntilThen

OctavianH said:


> A very nice article related to KT88 but not only those is this one:
> http://www.jacmusic.com/KT88/kt88.htm



A useful article thanks. I have Genalex Gold Lion KT88. Just bought Gold Lion KT77. Wonder why KT77 is not mention there. I also have the EH 6L6GC. KT77 is like a cross between KT88 and 6L6GC.


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## OctavianH

I have a pair of original Genalex Gold Lion KT77, the one from which they made the reissue, and it is a very warm and forgiving tube, on Elise. Warmer than KT88 or KT66.
From what I have read, it seems EL34 might be the same, but I never had the chance to try those. I will do it on Eternity.


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## UntilThen (Feb 1, 2021)

OctavianH said:


> I have a pair of original Genalex Gold Lion KT77, the one from which they made the reissue, and it is a very warm and forgiving tube, on Elise. Warmer than KT88 or KT66.
> From what I have read, it seems EL34 might be the same, but I never had the chance to try those. I will do it on Eternity.



What I am hearing from KT77 is that it sound like in between KT88 and 6L6GC. Those 2 extremes so it is a very good tone. More so towards the 6L6GC but with very good clarity and details. So far my favourite amongst all these 3.

I have a pair of brand new NOS GEC KT66 clear glass and Philips Miniwatt 6CA7 (EL34) double O rings xf2 coming in a weeks time. I am waiting on adapters from mrsxuling to run Cossor 801 and Telefunken EL12 spez in Elekit TU-8200. It's quite an incredible amp so far. Auto biasing.

There's also a brand new NOS pair of GEC KT88 that I'm thinking but it will cost AUD $1100 ... you only live once.


----------



## OctavianH

When you say KT77 is between KT88 and 6L6GC what is the scale you are referring to? Cold -> Warm or?


----------



## UntilThen

KT88 is north of neutral ie a bit bright. 6L6gc is south of neutral i.e a bit warm. KT77 leans more towards 6L6gc but not as warm.


----------



## OctavianH

UntilThen said:


> KT88 is north of neutral ie a bit bright. 6L6gc is south of neutral i.e a bit warm. KT77 leans more towards 6L6gc but not as warm.



And KT66?


----------



## UntilThen

I haven't got my KT66 and EL34 yet. In a week or more. Will be sampling those 2 tubes for the first time. I.e I have not heard KT66 and EL34... well that's not true... I heard the 2 x EL34 in Auris Nirvana 4 weeks ago at my downtown head-fi shop with LCD-4 and Susvara. EL34 is warm and romantic and I love it. Still details abound. Think HD650 scaling well with a good tube amp, that's what EL34 is.


----------



## UntilThen (Feb 1, 2021)

KT88 is a very nice tube imo. I love the details and force. There's a lot of punch under control in the right amp. However now hearing KT77 for the first time, I'm very impressed. Have you tried Cossor 801 with white ceramic base? Supposed to be a very good tone. Likewise Tung Sol 6550. I will be trying 5881 as well but most of all I want to try my 4 pairs of NOS EL12 spez in a proper amp now.

My seller has so many NOS power tubes. Pity he sold out on all KT66 smoke glass but some actually prefer the cleared KT66 clear glass. I love the smoke glass look. Like a smokey jazz bar kind of exotic.


----------



## OctavianH

Very interesting, thank you. I do not have any pair of 6L6GC but I have a quad of GE 7581A/KT66 which is, as far as I know, a 6L6GC. This fat one:







Never tried Cossor 801 but I have here a pair of GE 6550A and sounds quite nice, a very neutral and detailed tube, almost clinical. It reminds be about Tung Sol 7236, hard to say why. I know that Tung Sol 6550A are warmer than this one. My Eternity will have stock bias KT66 + 6J5, this is why I am very interested to know about it.


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## UntilThen (Feb 1, 2021)

You can't go wrong picking KT66 as stock bias because it's probably the most beautiful tone of them all, according to feedback from the Elekit thread.... except EL12 spez. This guy just love the EL12 spez. He says only the GEC TT21 beats it. I can't run TT21 in tu-8200 without power transformer replacement.

Your  quad of GE 7581A/KT66 is what I am after too. It's getting very expensive now. Also GE 6L6gc. Too many tubes to try. You and DL will have a lot of fun but I've already started here. 

This beauty .. TT21.


----------



## OctavianH

I know it sounds funny on a tube rolling thread, but my plan is to find out that GEC KT66 + GEC L63 are perfect and just enjoy music. The tube rolling options are there for safety if I change something or want to play from time to time. Of course, this might not happen so I'll be forced to roll.


----------



## UntilThen

OctavianH said:


> I know it sounds funny on a tube rolling thread, but my plan is to find out that GEC KT66 + GEC L63 are perfect and just enjoy music. The tube rolling options are there for safety if I change something or want to play from time to time. Of course, this might not happen so I'll be forced to roll.



Believe me staying with just 6j6 and gec kt66 won't happen. I know because here I told myself that too. Bought a 2nd hand Elekit tu8200 for $800 and I'm going to spend a bomb on tubes because each of these big power tubes are very unique in their tone. It's a big change from 6as7 / 6080. I can't believe that they are still rolling those big tubes in Elise and Euforia. Get a proper amp to run these big tubes and see them go. Just consider ourselves lucky we're not into 2a3 and 300b tubes yet because those are the killers.

What you can do is keep the NOS tubes as an investment and just run with current production tubes. Every public holiday, Christmas and your birthday roll in the NOS tubes to celebrate.  

Even the Genalex Gold Lion KT77, KT88 sound very good. I'm just curious how much better will the NOS tubes be. Well I'm about to find out but that means burning in those NOS tubes to at least 100 hours.


----------



## OctavianH

You are right, but the hope dies last.

GE 7581A/KT66 was around 70GBP at Langrex when I bought them. Now I think twice to buy from UK since they put taxes after Brexit.
And regarding reissues, I've sold or given away all my russian reissues except a pair of Tung Sol 7581A. So I'll stick to NOS and for me, the Reissued KT66 was around 70% compared with the NOS counterpart. Of course this is a very subjective evaluation, but even if the price/performance ratio favors the reissues, the NOS are still better.
Now, if it makes sense to buy NOS, well I think this is the principle of diminishing returns or something.


----------



## UntilThen (Feb 1, 2021)

Of course. Reissues are like wearing a fake Rolex. Well look at it this way. A NOS pair of GEC KT66 at AUD$600 will last you a life time. A NOS pair of GEC KT88 at AUD$1100 will extend your life by 20 years. Another pair of NOS Mullard EL34 xf2 with D getters will set you back at AUD$400 and extends your life..... forget it just enjoy it. Tubes are for using not for hoarding.

The guy who's selling me these NOS tubes must be laughing because he would have gotten them very cheap some 30 years ago.


----------



## OctavianH (Feb 1, 2021)

And because size matters, I plan to try these on Eternity:





I do not consider these as reissues since, as far as I know, KT120 and KT150 are new models.


----------



## UntilThen

Those KT150 are what I want to run on my Primaluna Dialogue Premium HP before I sold it off. All 8 of them.

Now there's one for sale and I'm thinking really hard..... 
https://www.stereo.net.au/forums/topic/337356-primaluna-dialogue-premium-hp-power-amplifier/


----------



## OctavianH

My wallet does not like you. I read about LCD-4 on one of your posts somewhere and I think about them for 2 days. I will not open the PrimaLuna thread because it is dangerous. LOL


----------



## UntilThen

OctavianH said:


> My wallet does not like you. I read about LCD-4 on one of your posts somewhere and I think about them for 2 days. I will not open the PrimaLuna thread because it is dangerous. LOL



It's only AUD$3500 like 3 pairs of GEC KT88. Cheap. 

I'm telling you this - LCD-4 with Qutest > Auris Nirvana is a nirvana experience but Hugo TT2 + M Scalar + Auris Nirvana + Susvara is like Saul being stricken on the road to Damascus. Not kidding you. It's an instant conversion. 

So.... I'm hoping that your Hugo TT2 + M Scalar + Eternity + GEC L63 + GEC KT66 + LCD-4 will do the same for you and I can't see why not because Sonic will surprise you with Eternity. When I had Oblivion just before Christmas 2019, I forget about Christmas completely. I forget about the turkey and the glazed ham. I forget about bad Santa. I was in total oblivion to the outside world as I pour over that amp. Now I have not heard it for one solid month. I'm going back this Sat and will try He1000se with it for the first time in my life. I await to be surprised.


----------



## OctavianH

I will not buy any other headphone except if I sell one. So I wait to be surprised, to decide that I keep T1 and sell Verite Open. In that case LCD-4 might be on the table. I sold last week ADX5000 because I was not quite using it.


----------



## UntilThen

I bought the T1.2 at full price, kept it for 3 months and sold off at half price including a Beyer balance cable. Compared to my other headphones, it's just not better and the fit on the ears is not covering the ears. I almost thought I could love it especially powered by a good tube amp. Ultimately I prefer my Audeze LCD-3f and LCD-X and now with the He1000se, I use that almost exclusively. I may need replacement ear pads due to over use.  

I love ZMF Verite at one stage but now I need headphones with clearer top end sparkle. LCD-3f, LCD-4 and He1000se has that and also great bass.


----------



## OctavianH

I think it depends on personal peference and rest of the chain. I still use my T1.2, which is my second pair, and consider it very good. It is true that the fit on the ears might be problematic but for me it is fine (hell knows, I have small ears maybe). Verite Open is better on most aspects, but heavier and therefore less comfortable. And I got scratches on it on the 2nd day because I put it on my table. Now I use a mouse pad to keep it on the table. What to say, I would love to have T1.2 sounding perfect on Eternity.


----------



## UntilThen (Feb 1, 2021)

Absolutely true. I don't normally recommend headphones to someone who's already happy with what they have. It's a personal thing as you say. I look at Skylab profile and he still have the DT880 there. 

Some and many swears by the HD650 but I keep that only because it's too cheap to sell and I use it to test tubes in case the tubes blows and damage my headphone drivers. Of course saying this on an open forum will draws dislikes from those who love HD650.

and you're right of course - it's system synergy and personal preference. I know someone who call the LCD-3f too bright. It's all relative and I won't mock anyone for what they like or dislike. It's a choice.


----------



## OctavianH

I had both HD650 and HD600 and considered them great, even if they were veiled. I sold both, but HD600 remained a long period in my collection.


----------



## hpamdr

@OctavianH @UntilThen Should we have a new thread about headphone rolling on UltraSonic amplifier.

About Headphone, I also have T1 and (modded)HD650 and HD800s .... When i bought the HD800s the plan was to sell the T1 but i finally kept it as it is really great match with F.A. Euforia and 5998 and 6n6gt for long relaxing session.

About tubes, I will try to wait for the amp before spending €€€ and in the meantime i will build adapter for FDD20, EL3N (input/output), EL11/12 EL3N (input/output), EL32, GU-50 output.... to be ready before receiving the amp and reading first impression from DL and OctaviaH.

@SonicTrance
*What is the expected power on the jack plug for the eternity/infinity (from 4 to 600 Ω) and impedance switch position.*


----------



## UntilThen

No need @hpamdr . Too many threads.  Besides there's not much to talk about headphones. Over the years I've seen people with certain preferences and that's ok. To a degree, most will think that what they have is the best.  and there's nothing with that because if you didn't like a headphone, you wouldn't have bought it in the first place.


----------



## OctavianH (Feb 2, 2021)

It is an interesting point: the adapters.

I already have and I am able to use:
- 7N7 => 6SN7
- 6F8G => 6SN7
- dual EL3N => 6SN7:






For outputs, since these are something new for me (6V6) I will soon receive *pairs* of:
- EL32 -> 6V6 (might also work for 6J7?)
- EL38 -> 6V6

What I would like to try, but I am not sure if I'll ever do it and I am not owning these at the moment, depending on how good are the "stock" tubes sounding:
- ECC31 -> 6SN7 (should work also for 6N7)
- C3g -> 6J5 (or dual to 6SN7)
- EL11 -> 6J5 (or dual to 6SN7)
- EL3N -> 6V6 (pair)
- EL11 -> 6V6 (pair)
- EL39 -> 6V6 (pair)

Now, I have no idea if a dual adapter to 6SN7 or dual 6J5 adapters make a difference. I would say no, but if someone has experience might advise.
In general I do not like adapters, I always prefer what I call "native" tubes which work difectly in the socket of the amplifier. To be sure those are reliable and easy to use I asked for upgraded sockets (teflon). I know many use socket savers, well, I am not quite liking those either if the amplifier is properly ventilated. Maybe I am crazy, but during early Elise days I heard some difference (in worse) using socket savers instead of directly plugging the tube in the amplifier.

PS. @hpamdr I will try to stick on topic but sometimes the fun of these threads are the off topic subjects like beer, metal, cable magic, balanced connection and so on. However I understood that you prefer to stick to the main subject and I will do my best to resist the demon of Off Topic which resides deep in my heart.

*Later Edit:* I also work on a tube compatibility list with different information, but it is not final so I will not add here. It would be an external link to an XLS sheet and I will be able to provide edit rights to whoever can contribute. I am not sure if this is the right path, but we can try. On that one I plan to mention needed adapters on each tube type.


----------



## hpamdr (Feb 2, 2021)

OctavianH said:


> - EL32 -> 6V6 (might also work for 6J7?)


In theory yes but what i have seen, is that 6j7 better works on "input" than output and really the opposite with EL32. So to use 6J7 as input, you will also have to get 6j7 to 6j5 adapter.


OctavianH said:


> - ECC31 -> 6SN7 (should work also for 6N7)


 Yes ECC31 and 6N7 have same pinout and almost same specification.


OctavianH said:


> Now, I have no idea if a dual adapter to 6SN7 or dual 6J5 adapters make a difference.


 @SonicTrance  Tomas do you have an idea ?
When the adapter is well built, this should not make any difference. But one for one is normally more respectful of the amp design and nicer...

With the EL3N adapter you show you need to be careful with the heating circuit on the PCB.Also I'm pretty sure no resistor is put  between g2 and Anode. Some claim that the sound seems to be better without, i do not agree and hat i know for sure is that almost all tube amp builder use the 100R resistor to strap pentode to triode.

// Edit : About headphone thread this is just a kind of humor.


----------



## OctavianH

When thinking about building myself adapters (and trying to forget how anti-talented I am in soldering) I was looking at this kind of boards:






Now, fixing 2 like these on a piece of wood and just making some wires long enough with proper pins to insert into the socket of the amplifier (or a socket saver here) might be a simple configurable octal adapter to test several types of tubes. Such a tube rolling kit is useful and I wonder why nobody made something like this already.


----------



## SonicTrance

hpamdr said:


> @SonicTrance
> *What is the expected power on the jack plug for the eternity/infinity (from 4 to 600 Ω) and impedance switch position*


You can see Infinitys power output on my website. Eternity will be much lower in power. I won't know the exact numbers until it's built and measured. 



hpamdr said:


> @SonicTrance Tomas do you have an idea ?
> When the adapter is well built, this should not make any difference. But one for one is normally more respectful of the amp design and nicer


I agree. It shouldn't make a difference but given the choice I'd choose the single adapter.


----------



## hpamdr

OctavianH said:


> When thinking about building myself adapters (and trying to forget how anti-talented I am in soldering) I was looking at this kind of boards:
> 
> 
> 
> ...


This board can be useful to experiment with tube and  but not to be used as an adapter as itself. You could complement it with this kind of tube base, you have pin numbering printed in both side. You have to be glue a small tube or a bolt in the center to remove with ease the base from the socket. To build adapter in a nicer way you can use tube and glue or this kind of base.


----------



## SonicTrance

hpamdr said:


> This board can be useful to experiment with tube and  but not to be used as an adapter as itself. You could complement it with this kind of tube base, you have pin numbering printed in both side. You have to be glue a small tube or a bolt in the center to remove with ease the base from the socket. To build adapter in a nicer way you can use tube and glue or this kind of base.


If you use that kind of board with long wires attached they become antennas for noise pickup as well. Especially grid wires for the input tubes are extremely sensitive. You could use shielded wires of course to get around that problem.


----------



## OctavianH

SonicTrance said:


> If you use that kind of board with long wires attached they become antennas for noise pickup as well. Especially grid wires for the input tubes are extremely sensitive. You could use shielded wires of course to get around that problem.



I never thought too much about it. I only wanted to exemplify a kind of "adjustable adapter" which can be a useful tool for the tube roller.

By the way guys, in order to show my tube collection that I make no discrimination, I just bought a pair of gay tubes. Yes! My tubes can have what sexual orientation they like.
More exactly: a pair of 6L6GAY! Now the black or grey coated tubes which always tell me that I always prefer clear glass have nothing more to say. I hardly wait to receive them.


----------



## SonicTrance

OctavianH said:


> I never thought too much about it. I only wanted to exemplify a kind of "adjustable adapter" which can be a useful tool for the tube roller.
> 
> By the way guys, in order to show my tube collection that I make no discrimination, I just bought a pair of gay tubes. Yes! My tubes can have what sexual orientation they like.
> More exactly: a pair of 6L6GAY! Now the black or grey coated tubes which always tell me that I always prefer clear glass have nothing more to say. I hardly wait to receive them.


I needed a laugh today. Thank you!


----------



## hpamdr

SonicTrance said:


> If you use that kind of board with long wires attached they become antennas for noise pickup as well. Especially grid wires for the input tubes are extremely sensitive. You could use shielded wires of course to get around that problem.


You are more than right, this can be only a temporary test. To prevent antenna effect you can cover the "in air" adapter with tube in a metallic can once placed on the amp. This works only if you have enough space on the amplifier and with single tube unless you have big metallic box...

@OctavianH you can use beer can once opened and add insulating tape to the bottom to protect the amp. 

@OctavianH @SonicTrance :: I think that a big warning should be put on top of this thread about possible damage can occurs to the amp if wrong tube is placed or wrong adapter is used.. In case of short circuit, you an blow capacitor or worse. I think Tomas can sentence it in better way.


----------



## OctavianH (Feb 3, 2021)

hpamdr said:


> @OctavianH @SonicTrance :: I think that a big warning should be put on top of this thread about possible damage can occurs to the amp if wrong tube is placed or wrong adapter is used.. In case of short circuit, you an blow capacitor or worse. I think Tomas can sentence it in better way.


I put a warning about tube rolling in the 3rd post. Also with  signs. I will, of course, add more if necessary.

Brrr, I grabbed also a pair of Sylvania 5932 for 50 EUR. My mother always told me not to play with Ebay.


----------



## hpamdr (Feb 3, 2021)

I missed the warning on post 3...


OctavianH said:


> *Clarification needed:*
> 
> Situation of Melz 6H12C



6n12s could be used in input stage but not in output. But it could be on the limiting value 4ma by triode at 200V with -15V on the grid. I would personally avoid it and keep it for OTL as output tube.



OctavianH said:


> Situation of 6F6G
> Situation of EL35 (probably not)
> Situation of 5881
> Situation of 5932 (more powerful 6L6)



All seems to be OK for me. The EL35 is almost the same as EL5 and EL36, infinity will have no issue at all to bias. @SonicTrance  With eternity this should be OK but we need to get the right voltages and limits to bias at 20mA ..


----------



## OctavianH

@hpamdr And I also think 6CA7 should be fine as output for both Infinity/Eternity. What do you think?


----------



## DecentLevi (Feb 3, 2021)

UntilThen said:


> Hi folks, I just pick up a Elekit 8200. So will be rolling KT88, 6L6G, EL34, KT77, KT66, EL12 spez.


UT gets an ELkit amp? I wouldn't expect it any other way   ... this is of course coming from UntilThen,#1 fan and master trailblazer of all EL tubes on Head-Fi. How could I ever forget your unwavering proclaim of the good old EL3N, followed by EL11, 12, Spez,... then H1 broke out the EL32, EL38, 39, now we know the 34, 36, etc. Good tubes indeed.


----------



## UntilThen

DL, I don't want to derail this thread but you can hop over to the Elekit 8200 thread for my impression of this Japanese marvel kit. Drives speaker and headphones. In addition to a lot of NOS tubes I'm getting - the sum total is many times more than the price of the amp... and I'm getting a matching TU-8500 which is a preamp and phono stage to partner the TU-8200. 8w in ultranlinear mode and 8.2w in pentode mode and 4w in triode mode.

Getting GEC KT66, Philips Miniwatt EL34 / 6CA7 xf2, GEC KT77, Tung Sol NOS 6550, Radiotron 807 D^D, and a whole lot more.... finally I'll leave the best and most expensive to the last - GEC KT88 at AUD $1100 a pair.


----------



## DecentLevi

Wow UT, do you prefer the ELkit more than the Ultrasonic Oblivion or the Alo Audio Studio Six amp? Amazing sounding collection. You should be able to use most with a future Ultrasonic Eternity amp should you get one too.

Also guys, in case anyone missed it on the 2359Glenn thread, they've discovered a tube class called *6J7*. It's a pentode and the successor of 6C5. It's compatible in a 6J5 socket (as two single tubes with two adapters), or 6SN7 socket (as two dual tubes in a single adapter).

These 6J7's actually work with an EL32 adapter including with the same top connection; in the above mentioned tube sockets. I verified this with adapter maker @Deyan and another user. Further I was told these can also work as output tubes in the KT66/EL34 socket with the same EL32 adapter, in single mode. I'm not sure if the grid bias would be of concern or not though when using as an output tube. As you can see there's both metal 6J7 and ST (curved) versions called 6J7G, going way back to the era of curvey tubes that not only look beautiful but many sounding more organic and rich in general.

metal 6J7




ST / curved 6J7G - many versions of these


----------



## DecentLevi (Feb 3, 2021)

SonicTrance said:


> Yes! I'll make it easy for you and say that all output tubes, except for the EL32 @ 40mA, should run @ 50mA.
> ...
> You can measure yourself with the DMM set to at least 300VDC. Put black probe in black banana jack and red probe in pin 3 of the output tube socket. You count the pins counter clockwise from the guidepin. When the voltage is down to a couple of volts you're fine.
> 
> Hope that helps.


Wow Tomas I get what your saying but it seems surprising. Do you mean to say that out of all the output tube types I listed for my amp I will set everything at the same 50mA grid voltage adjustment except for the EL32 at 40mA? I really want to ensure these are all set to the most optimal operating point so I don't mind fine tuning to to more exact bias amounts, if you have more precise recommendations.

Also all the input tubes I wanted to use are the same at 4mA so no adjustment needed?




So pin 3 for my KT66 socket would be at the black arrow above, right? And facing towards me this would be in reverse.


----------



## UntilThen

DecentLevi said:


> Wow UT, do you prefer the ELkit more than the Ultrasonic Oblivion or the Alo Audio Studio Six amp?



Those 3 amps are very unique in their own ways. These days I don't say outright that one is definitely better than the other. I've sold off my Studio Six btw. Oblivion is still with me but Elekit 8200 is exciting in being able to roll all those big tubes with auto bias and sound great.


----------



## UntilThen

DecentLevi said:


> UT gets an ELkit amp? I wouldn't expect it any other way



After you read all the glowing reviews, you will know why I'm impressed with what I heard.
https://www.head-fi.org/threads/elekit-300b-amp-kit.869957/post-14049028


----------



## SonicTrance

DecentLevi said:


> Do you mean to say that out of all the output tube types I listed for my amp I will set everything at the same 50mA grid voltage adjustment except for the EL32 at 40mA?


You need to understand the tube curves, Levi. The mA meters on the amp will measure plate current. We always want the plate current the same at 50mA with the exception of the EL32 at 40mA. The plate voltage is fixed at 200V. To reach the 50mA plate current we set the grid voltage. That voltage will be very different for different tubes.

Here's two examples:
This is the 6V6 tube. As you can see I've drawn red lines from 200Va and 50mA Ia. Those lines intersect at about -7Vg (look at the grid curves!). So to get 50mA of plate current for the 6V6 you set the grid voltage to -7V with the help of your external DMM connected at the measuring points on the amp.


Here we have the KT88. Plate voltage is still same of course at 200V. We still want our 50mA Ia. This time the red lines intersect at about -19Vg. So to use the KT88 you set the grid voltage to -19V. 


If you would insert the KT88 with the grid voltage set to -7V (setting for the 6V6), how much current would it draw? About 180mA! Bad things would happen at that point, lol! It's important you understand this.



DecentLevi said:


> Also all the input tubes I wanted to use are the same at 4mA so no adjustment needed?


Adjustments are needed just the same as the output stage. It all about the curves! Study them!  

Btw, just to make things more complicated you can also use the 6SL7/ECC35 in the input stage! This will need to be run at 3mA instead of 4mA


----------



## OctavianH (Feb 4, 2021)

@SonicTrance A protection mechanism to limit the current to a max value (i.e. 50mA on the example above) cannot be done?
(and not fuses)


----------



## SonicTrance

OctavianH said:


> @SonicTrance A protection mechanism to limit the current to a max value (i.e. 50mA on the example above) cannot be done?
> (and not fuses)


Why not fuses? I can fuse the output and input tube cathodes. Output tubes at 125mA combined and input tubes at 10mA combined. Can have the fuses on back panel. I guess it's a good idea.


----------



## OctavianH

SonicTrance said:


> Why not fuses? I can fuse the output and input tube cathodes. Output tubes at 125mA combined and input tubes at 10mA combined. Can have the fuses on back panel. I guess it's a good idea.



I was thinking that fuses are not efficient at low currents, and I am not sure if this is not affecting the whole circuit in any way. If you say it makes sense ignore me.


----------



## SonicTrance

OctavianH said:


> I was thinking that fuses are not efficient at low currents, and I am not sure if this is not affecting the whole circuit in any way. If you say it makes sense ignore me.


They're are efficient. Problem with low current fuses is that they are very expensive below 10mA. But 10mA fuses are fine if I combine the cathodes. I'll incorporate this into the tube rolling add-on! You still need to carefully set the grid bias though. 

Update on the builds: 
I'm still waiting for Levi's chassis. The supplier has not shipped it yet. I emailed them yesterday and some panels are still anodizing. Slight delay in build time is to be expected.


----------



## OctavianH

SonicTrance said:


> They're are efficient. Problem with low current fuses is that they are very expensive below 10mA. But 10mA fuses are fine if I combine the cathodes. I'll incorporate this into the tube rolling add-on! You still need to carefully set the grid bias though.



Ok, just tell us for each version (Infinity/Eternity) what fuses to use, I have a feeling we'll need a bunch.


----------



## SonicTrance

OctavianH said:


> Ok, just tell us for each version (Infinity/Eternity) what fuses to use, I have a feeling we'll need a bunch.


Will do! I'll test with 10mA for input stage and 125mA for output on Infinity and 10mA input 50mA output for Eternity. It have to be slow blow fuses. This will work as there's no current surge at startup on the plate current. The tubes slowly start to conduct as they heat up, but will draw slightly more current at first. If you blow a fuse the meter will go to zero. You then turn the amp off, insert new fuse and power on again.


----------



## hpamdr

SonicTrance said:


> We always want the plate current the same at 50mA with the exception of the EL32 at 40mA.


 This is for infinity, But can you explain why ? For eternity does all output tubes will be biased as 20 or 25mA


SonicTrance said:


> Btw, just to make things more complicated you can also use the 6SL7/ECC35 in the input stage! This will need to be run at 3mA instead of 4mA


 As bias is the same for eternity can you explain why to bias for lower value ? This will also the same with 12AX7 ?



SonicTrance said:


> Why not fuses? I can fuse the output and input tube cathodes. Output tubes at 125mA combined and input tubes at 10mA combined. Can have the fuses on back panel. I guess it's a good idea.


 fuse are indeed a good solution for protection for faulty bias or some flashing tube. But it need to not add too long wire and not let people going in the game of fuse rolling 

(Off Topic) I have standard fuse on my loudspeaker but you have many post on owner forum arguing about silver, copper, gold,....bringing some difference in sound... lol


----------



## OctavianH

hpamdr said:


> (Off Topic) I have standard fuse on my loudspeaker but you have many post on owner forum arguing about silver, copper, gold,....bringing some difference in sound... lol


As long as you do not care also about the direction the current flows through it you are fine. I know people who burned in very expensive fuses in one way and then sold it with marker to know how to mount it.

I googled a little bit and I cannot find anywhere fuses smaller than 50mA. So those at 10mA are a mistery to me.


----------



## SonicTrance

hpamdr said:


> This is for infinity, But can you explain why ? For eternity does all output tubes will be biased as 20 or 25mA


We need to run the EL32 cooler because of the max plate dissipation rating.

All output tubes should be run at 20mA in Eternity. If you run them at 25mA and I fuse att 50mA the fuse will blow.

The reason the current needs to be the same is because of the gyrator plate loads. There's a resistor from gyrator source to tube anode. That resistor needs to drop around 10V for the gyrator to work optimally.
3-4mA on input stage and is ok. 



hpamdr said:


> As bias is the same for eternity can you explain why to bias for lower value ? This will also the same with 12AX7 ?


Because of max plate dissipation. The 6SL7 has a max dissipation of 1W. Running it at 3mA and 200 Va is 0.6W. We don't want to run the tubes too hot.
12AX7 will also work at 3mA.



hpamdr said:


> fuse are indeed a good solution for protection for faulty bias or some flashing tube. But it need to not add too long wire and not let people going in the game of fuse rolling


The wire will be quite long but it's in the path to ground so should be fine. 



OctavianH said:


> I googled a little bit and I cannot find anywhere fuses smaller than 50mA. So those at 10mA are a mistery to me.


https://www.tme.eu/se/details/0313.010hxp/sakringar-6-3x32mm-troga/littelfuse/


----------



## hpamdr

SonicTrance said:


> We need to run the EL32 cooler because of the max plate dissipation rating.
> 
> All output tubes should be run at 20mA in Eternity. If you run them at 25mA and I fuse att 50mA the fuse will blow.
> 
> ...


This is to preserve tube so we do not have a fixed value but an optimal range to respect both gyrator and tube. 
About fuse, you will put one for drivers and one for outputs ?


----------



## SonicTrance

hpamdr said:


> This is to preserve tube so we do not have a fixed value but an optimal range to respect both gyrator and tube.
> About fuse, you will put one for drivers and one for outputs ?


Yes, one fuse for each stage. 10mA for inputs (both channels combined) and 50mA for the output stages in Eternity.


----------



## OctavianH

Talking about adapters, I've just received these from Poland. They are looking nice, I had a pair of 6F8G->6SN7 and now I received also EL3->6V6 and EL38->6V6.






And now time for some tube pr0n. I also grabbed a pair of Westinghouse 6V6G at a very good price.


----------



## OctavianH

Since everyone is speaking about KT88 and the huge price of GEC on several threads I searched a little bit in my pictures archive. Some time ago I was able to buy at a good price some KT88 tubes made for Ayon amplifiers. An owner of such a speaker amplifier was selling 5 pieces. The culprits are below, near 2 of the Genalex KT88 russian reissues:





I have sold during time the russian reissues, and gave away 2 of the 5 Ayon KT88 tubes but I still have 3 of them. At that time, because these were not available anywhere, I searched for information and found a polish article. When trying them in Elise, even as a quad, the sound signature was much warmer than of the russian counterparts.





Does anyone know more about these tubes? I plan to try these in Eternity sometimes.


----------



## hpamdr

OctavianH said:


> Since everyone is speaking about KT88 and the huge price of GEC on several threads I searched a little bit in my pictures archive. Some time ago I was able to buy at a good price some KT88 tubes made for Ayon amplifiers. An owner of such a speaker amplifier was selling 5 pieces. The culprits are below, near 2 of the Genalex KT88 russian reissues:
> 
> 
> 
> ...


If i recall corectly the tube used in Ayon are built by  Shuguang using Ayon spec (This should be a variation of the "Natural" KT88-T ).


----------



## OctavianH

hpamdr said:


> If i recall corectly the tube used in Ayon are built by  Shuguang using Ayon spec (This should be a variation of the "Natural" KT88-T ).



I think so, these are chinese tubes made by Shuguang. I never owned other chinese tubes and on internet the opinions are splitted. Some say these are not reliable, others say that these are good. I have a pair of PsVane CV181T2 and I quite like them but about Shuguang or Ayon I do not know much. Soundwise, I preferred these to the russian remakes, but the signature was different. These were warmer, towards KT77.


----------



## hpamdr

OctavianH said:


> I think so, these are chinese tubes made by Shuguang. I never owned other chinese tubes and on internet the opinions are splitted. Some say these are not reliable, others say that these are good. I have a pair of PsVane CV181T2 and I quite like them but about Shuguang or Ayon I do not know much. Soundwise, I preferred these to the russian remakes, but the signature was different. These were warmer, towards KT77.


One of my fiend using Jadis amplifier like more the russian GL KT88 reisue but told me they need a bunch of running time before reaching best sound. He tested PsVane and Shanguang but find the sound of the reissue not as natural and a bit warmer. On his new amp he use 4 GU-50 by side ....


----------



## OctavianH (Feb 6, 2021)

hpamdr said:


> One of my fiend using Jadis amplifier like more the russian GL KT88 reisue but told me they need a bunch of running time before reaching best sound. He tested PsVane and Shanguang but find the sound of the reissue not as natural and a bit warmer. On his new amp he use 4 GU-50 by side ....



I am sure that he might be closer to the real sound than me using these in an amplifier not built for them. I guess  I will find the truth when biasing Eternity for KT88. I will not be able to try again the russian remakes but I will have a lot of tubes to try. The GU-50 is the "jack of all trades" and if Sonic makes and amp for speakers and headphones with these he will become a very rich man.  But I told him this already


----------



## hpamdr

From bias perspective the GU-50 seems on the limit even for 20mA with 200V and -31.52V on the grid for bias the load is 5KOhm like KT88. 
Did i missed something @SonicTrance


----------



## SonicTrance

hpamdr said:


> From bias perspective the GU-50 seems on the limit even for 20mA with 200V and -31.52V on the grid for bias the load is 5KOhm like KT88.
> Did i missed something @SonicTrance


When using the calculator the load is not important. The actual load the gyrator provides is much much higher. You can put a bunch of zeros after the 5k so the load line becomes flat. 
The grid curves will be better, more linear, in real life than they look using that calculator.
No problem running the GU-50. As long as you have a 12v heater supply of course


----------



## OctavianH

I told you guys some days ago that I make a kind of tube compatibility guide. For example, I think about a table like this:




But I've seen that some tube types need special operating points, so maybe the list of preconditions to meet for a tube to be usable should be the first step. Then, of course, try something like this. The table is not final nor accurate, just an example. What do you think?


----------



## hpamdr (Feb 6, 2021)

OctavianH said:


> I told you guys some days ago that I make a kind of tube compatibility guide. For example, I think about a table like this:
> 
> But I've seen that some tube types need special operating points, so maybe the list of preconditions to meet for a tube to be usable should be the first step. Then, of course, try something like this. The table is not final nor accurate, just an example. What do you think?


*This is great* you should probably add infinity bias for output (200V / 40-50ma) or split in 3 sections Input tubes (highlight the 3ma bias), eternity output tubes, infinity output tubes bias 50ma/40ma (EL32). This can also be in a shared folder with limited editing right.
I will try to get a uTracer3+ and a small training next month, i will try to measure some pentode once strapped  as designed..._(need to wait....)_


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## OctavianH (Feb 6, 2021)

hpamdr said:


> *This is great* you should probably add infinity bias for output (200V / 40ma) or split in 3 sections Input tubes (highlight the 3ma bias), eternity output tubes, infinity output tubes bias 50ma/40ma (EL32). This can also be in a shared folder with limited editing right.
> I will try to get a uTracer3+ and a small training next month, i will try to measure some pentode once strapped  as designed..._(need to wait....)_



Wow, you really take it as a true professional. You are lucky to do that. I always wanted to have at least a tube tester. Well, this is doable, so maybe I'll buy a tube tester in the following months. Shhht, my girl should never hear of this. 

And yes, you are right I should somehow add Infinity into this but I am still evaluating how we should do this in the best way, 2 tables or maybe one with all infos. We will see how this will go, it seems people consider this useful so I'll do my best to obtain the best form.


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## hpamdr (Feb 6, 2021)

OctavianH said:


> Wow, you really take it as a true professional. You are lucky to do that. I always wanted to have at least a tube tester. Well, this is doable, so maybe I'll buy a tube tester in the following months. Shhht, my girl should never hear of this.


This will be a loan for 2/3 weeks. The friend who built it from kit will go on holiday if he can travel in March and will let me use it.
---edited---
I already have an old tube tester (lampemètre service 44) but this is not enough to get curves, It gives an indication of the wear level and know if used tubes are OK or KO.


----------



## OctavianH (Feb 6, 2021)

hpamdr said:


> This will be a loan for 2/3 weeks. The friend who built it from kit will go on holiday if he can travel in March and will let me use it.



This will be very useful for us, especially if we want to try some tube which does not have any triode connection graphs. Or at least this is how I understand it.
In the meantime I will try to improve that table and think how we can make it editable by everyone and the first choice would be Google Drive. But I am still thinking if other possiblities are better, the power of that table are the users, let's hope there will be more Eternity/Infinity users with the Tube Rolling add-on.

Later edit:

@hpamdr I tried to edit the table adding Infinity. I assumed input stage is operating at the same point of 180V/4mA and only the output stages are different. What do you think about this? (those 40mA or 50mA can be specified per tube type)


----------



## hpamdr

OctavianH said:


> This will be very useful for us, especially if we want to try some tube which does not have any triode connection graphs. Or at least this is how I understand it.
> In the meantime I will try to improve that table and think how we can make it editable by everyone and the first choice would be Google Drive. But I am still thinking if other possiblities are better, the power of that table are the users, let's hope there will be more Eternity/Infinity users with the Tube Rolling add-on.
> 
> Later edit:
> ...


We just need to wait and get the amp for final test. In the meantime, Tomas @SonicTrans will test a bunch from Levi's collection during the final testing phase on infinity... He can add some comment and share some data.


----------



## OctavianH

hpamdr said:


> We just need to wait and get the amp for final test. In the meantime, Tomas @SonicTrans will test a bunch from Levi's collection during the final testing phase on infinity... He can add some comment and share some data.



Yes, of course. I am just preparing. If this table is not useful in this form we can just make 2 tables for each amplifier and everyone can fill their own values there. I would say we are on a good track with this approach.


----------



## DecentLevi

Brief comment - nice looking formula. We'll later add more such as the miniature 9-pin octals is that's the right word and that's right Tomas is testing mine I sent. Maybe data on EL3N will have to be improvised however because I forgot to include the adapters. Then we'll definitely need to update the V(oltage) values a lot according to his feedback, as well as some mA values which will especially be different for the likes of EL32 and EL12 Spez.

But I think we should have one separate document for each Infinity and Eternity. That would make the appearance more concise, and after all most users are going to have one or the other.


----------



## OctavianH

Ok, I have updated the chart and put a link read-only to it on the 3rd post. What I have changed:
- splitted the spreadsheet in 2 sheets: Infinity and Eternity 
- added 6SL7 and ECC35 as inputs without adapter to 6SN7 (seems the same pinout, correct me if I'm wrong)
- changed and marked in red all different operating points (EL32,ECC35,6SL7)
- put some row numbering for safety near tube type/grid bias columns to help
I am not sure how I can make this editable by specific users, or how is the best way to proceed here:
1) we keep it read only and I update it based on new posts on the thread
2) I make it editable for everyone (not sure if Google Drive has other options in this area)
If anyone thinks we can do this in a better way (store it in other place for example) just copy the table, alter it and when finished I'll update the post with the new link. If not, remains like this.


----------



## SonicTrance

The chart is a great idea! Well done! I don't have time to check it for faults now but I'm sure you got it covered =)


----------



## hpamdr

OctavianH said:


> I make it editable for everyone (not sure if Google Drive has other options in this area)


If you use Google Docs services instead of GDrive, and specially google Sheet you can share the spreadsheet and remote user can ask for edition rights. (I've used it in the past)


----------



## OctavianH

Ok, I'll see how to move it from Drive to Sheets. Honestly I never knew that there is a difference.


----------



## OctavianH

hpamdr said:


> If you use Google Docs services instead of GDrive, and specially google Sheet you can share the spreadsheet and remote user can ask for edition rights. (I've used it in the past)



I tried today to move this table to sheets but the link takes me to the same place it already is. For example, I press this button:





And it takes me to the same docs.google.com. In settings I have:





So maybe Google Sheets and Google Docs are the same, so we already have the table where it should be and we should be able to add people to edit it or that feature was for Business? I have no idea, but we will figure this out.


----------



## hpamdr (Feb 8, 2021)

OctavianH said:


> I tried today to move this table to sheets but the link takes me to the same place it already is. For example, I press this button:
> 
> ...
> 
> So maybe Google Sheets and Google Docs are the same, so we already have the table where it should be and we should be able to add people to edit it or that feature was for Business? I have no idea, but we will figure this out.


 Yes Google Sheet is part of Google Docs.. So we already have a file in the cloud. 
--  Edited once file accessed  --
I propose to have 3 tabs [Inputs], [Output Infinity], [Output Eternity] to not duplicate inputs.


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## OctavianH (Feb 8, 2021)

hpamdr said:


> Yes Google Sheet is part of Google Docs.. So we already have a file in the cloud.
> --  Edited once file accessed  --
> I propose to have 3 tabs [Inputs], [Output Infinity], [Output Eternity] to not duplicate inputs.



Ok, so to have 3 sheets? We can do this, the reason I've done it like this was because I am not sure if all inputs are the same in both amplifiers. For example, as far as I know EL32 might be usable in Infinity as input, but not in Eternity. And maybe some operating points are not the same in both amplifiers in some special cases. Of course, here Sonic might advice how to make this strucuture in the best way. I gladly modify it or maybe make 2 versions and we decide later which one we keep.

Edit:
I have created another version like requested, now we have 5 sheets:
- 1 and 2 are my initial version / amplifier
- 3,4 and 5 are the new version / stage
When we decide which one is better I'll delete the other.
@hpamdr this is what you asked for?


----------



## hpamdr

OctavianH said:


> Ok, so to have 3 sheets? We can do this, the reason I've done it like this was because I am not sure if all inputs are the same in both amplifiers. For example, as far as I know EL32 might be usable in Infinity as input, but not in Eternity. And maybe some operating points are not the same in both amplifiers in some special cases. Of course, here Sonic might advice how to make this strucuture in the best way. I gladly modify it or maybe make 2 versions and we decide later which one we keep.
> 
> Edit:
> I have created another version like requested, now we have 5 sheets:
> ...


 This was a suggestion ! 
What you do is great  About input tubes only available in infinity, we could just add a remark or colorize the tube cell.


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## OctavianH (Feb 8, 2021)

hpamdr said:


> This was a suggestion !
> What you do is great  About input tubes only available in infinity, we could just add a remark or colorize the tube cell.



Then let's see what Sonic and Levi say and I will delete the version which we agree it is worse.
About input tubes with different operating points or not available in both we can use the remark column or add the tube twice (once for Infinity, once for Eternity) in the same column. For me it is the same, both tables have strenghts and weaknesses, so I do not really care about which one we use, I will let majority decide.

On a much happier note than Excel files, the GAY tubes are quite beautiful.


----------



## SonicTrance

OctavianH said:


> Ok, so to have 3 sheets? We can do this, the reason I've done it like this was because I am not sure if all inputs are the same in both amplifiers. For example, as far as I know EL32 might be usable in Infinity as input, but not in Eternity. And maybe some operating points are not the same in both amplifiers in some special cases. Of course, here Sonic might advice how to make this strucuture in the best way. I gladly modify it or maybe make 2 versions and we decide later which one we keep.


The input stages will be identical for both Eternity and Infinity. So those settings/tubes will be usable for both amps. The output stages will have different settings though of course.


----------



## hpamdr

OctavianH said:


> Then let's see what Sonic and Levi say and I will delete the version which we agree it is worse.
> About input tubes with different operating points or not available in both we can use the remark column or add the tube twice (once for Infinity, once for Eternity) in the same column. For me it is the same, both tables have strenghts and weaknesses, so I do not really care about which one we use, I will let majority decide.
> 
> On a much happier note than Excel files, the GAY tubes are quite beautiful.


I was hopping purple base


----------



## OctavianH

hpamdr said:


> I was hopping purple base


Nothing can stop me to improve them. Now better?


----------



## UntilThen

Pick up a new pair of RFT (Siemens) EL34 cheap. Box is as good as new. I do like EL34.


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## OctavianH

Those are looking very nice, however, I made a deal with my wallet and the deal is as follows: I will not buy any other tube until I receive the amplifier and understand how these are sounding on this specific circuit. Then, I might order these or others like them.


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## UntilThen (Feb 11, 2021)

I know the tubes I buy will sound good because my amp is the traditional old school design. Also I can use these tubes straight away in Elekit TU-8200. That the nice thing. My tubes will be able to be used in 2 amps.

I see the title says only for Infinity and Eternity tube rolling. Guess I need a separate one for Odyssey tube rolling.


----------



## hpamdr

UntilThen said:


> I know the tubes I buy will sound good because my amp is the traditional old school design. Also I can use these tubes straight away in Elekit TU-8200. That the nice thing. My tubes will be able to be used in 2 amps.
> 
> I see the title says only for Infinity and Eternity tube rolling. Guess I need a separate one for Odyssey tube rolling.


Octavian can put a note but it seems that you will need a completely separate section for bias adjustment. With few tubes spec, it can be already pre-tuned in your amp using switches and resistors.. @SonicTrance can probably build such presets for you.


----------



## OctavianH

UntilThen said:


> I see the title says only for Infinity and Eternity tube rolling. Guess I need a separate one for Odyssey tube rolling.



I gladly add also Odyssey on the title, but I guess you will not have the same design. Should I edit? Or do you want a separate thread?


----------



## UntilThen

OctavianH said:


> I gladly add also Odyssey on the title, but I guess you will not have the same design. Should I edit? Or do you want a separate thread?



Well no point in grandstanding. Just make it generic Ultrasonic Studio amps tube rolling because there will be more amps with different custom design and tube requirements. It would be absurd to create a separate thread for each.


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## OctavianH (Feb 11, 2021)

UntilThen said:


> Well no point in grandstanding. Just make it generic Ultrasonic Studio amps tube rolling because there will be more amps with different custom design and tube requirements. It would be absurd to create a separate thread for each.



I agree with that, I did not knew at the beginning how this will turn. I will make it generic and maybe split somehow the description and content in the first posts.

Edit:

I edited the thread title, added a 3rd option as Odyssey + a few words about it from the other thread. For Tube Compatibility Guide we can make a separate sheet in the same XLS for it or even a different file. No problem from my side.


----------



## UntilThen

Thanks @OctavianH . Also I'm not going to be pig headed and will not insist that Odyssey will remain unique and one and only. If Tomas decide to use that name for subsequent amps of same design. I'm perfectly ok with that ! In fact it should be otherwise it's hard to categorise his amps if each and everyone has a separate name. I think that make sense. In fact I toss the idea of calling it Odyssey to Tomas. If he didn't agree with that, I'm perfectly ok! Could have call it Xanadu ....


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## OctavianH (Feb 12, 2021)

UntilThen said:


> Thanks @OctavianH . Also I'm not going to be pig headed and will not insist that Odyssey will remain unique and one and only. If Tomas decide to use that name for subsequent amps of same design. I'm perfectly ok with that ! In fact it should be otherwise it's hard to categorise his amps if each and everyone has a separate name. I think that make sense. In fact I toss the idea of calling it Odyssey to Tomas. If he didn't agree with that, I'm perfectly ok! Could have call it Xanadu ....



Of course, when the amplifiers will be built and the website edited, I will edit the first post and make standard descriptions for each of them, put real pictures of each one, remove our names and so on. We can keep somewhere a list with the amplifiers and names but it is not really necessary. At the moment the information is preliminary with what I could gather from everyone. Odyssey is a beautiful name. For me Eternity is also special since it is one of my all time favourite albums.


----------



## hpamdr

@SonicTrance
Do you think we can also maintain a budget tube list. Good sound for the buck with rusian equivalent or multipart tube having triode well sounding !


----------



## OctavianH (Feb 12, 2021)

Friday, Beerday, Tube Pr0n day. 6x6v6. Evil combo 






Here are the greymen:





And my favourites:





Yep, you caught me. I have OCD and I like sets. 

We have a problem at this last one, different logos, but same getter. I have a pair with the same logo as the 6J5 but inverted cup getter. The world is not perfect guys.


----------



## UntilThen

Very nice. I'm going out soon. I will roll out my Odyssey tubes later for a bikini photo shoot and a completely bare all. Centrefold !


----------



## OctavianH

UntilThen said:


> Very nice. I'm going out soon. I will roll out my Odyssey tubes later for a bikini photo shoot and a completely bare all. Centrefold !



For today is enough. Next friday, next tube pr0n.


----------



## UntilThen

Radiotron 807


----------



## OctavianH

Ok, you tempt me UT!

A pair of GE 6550A and a pair of Genalex KT77.


----------



## UntilThen

Just spoke to my ‘supplier’ and I have reserved:-

GEC KT88 brand new
GEC KT77 lightly used
Tung Sol 6550 1960s lightly used
Canadian 807 rare
Radiotron 807 picture as above
Brimar 6l6g and ga black glass ultra sexy

oh he has some very rare 6sl7 if I decide to use that as drivers instead of 12au7.

when I talk to him about kt150, he said those you can get anywhere they are cheap Russian tubes 🤪


----------



## UntilThen

Ok he send me a picture and my knees go soft 😂

What brand new how can I burn it up 😝


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## OctavianH (Feb 13, 2021)

Well, you are right, but my knees got soft on this UDO performance:



Later edit:

I watched on Thursday how 2 pieces of NOS GEC KT88 sold for 640 GBP. In EUR, including shipping they were close to 800 EUR. Thanks, but no, thanks. I think about a pair of PsVane KT88 II which sell around 200 EUR. For me the CV181T2 were good, if these are close, it seems to be a much better deal for me.

Edit 2:

To avoid double post. I've seen that 807 are quite cheap on Ebay, I think it makes sense to obtain an adapter.





And I found a website which fills with beer tubes:
https://www.qsl.net/kb7rgg/radio/807/807specs.html
Guys, this is something spectacular. To drink from a tube, LOL.


----------



## OctavianH

Hmm, my mother always told me not to play with Ebay. Well, I've just bought:





Eternity wil love these.


----------



## UntilThen

In addition to the Radiotron, I'm getting this pair of rare Canadian maple 807.


----------



## UntilThen

OctavianH said:


> Hmm, my mother always told me not to play with Ebay. Well, I've just bought:



I have 2 pairs of adapters if you need one pair... I will send it to you if you want. One pair that is.


----------



## OctavianH

I just love the base with that leaf on it! Reminds me of:


----------



## OctavianH

UntilThen said:


> I have 2 pairs of adapters if you need one pair... I will send it to you if you want. One pair that is.



I've just wrote a message to my guy in Poland to make me some 807 -> 6V6 adapters and also a pair of EL39 -> 6V6 because I might buy a pair soon.
If he does not have time for me, I'll write you and of course, pay for it. Thank you!


----------



## UntilThen

OctavianH said:


> I've just wrote a message to my guy in Poland to make me some 807 -> 6V6 adapters and also a pair of EL39 -> 6V6 because I might buy a pair soon.
> If he does not have time for me, I'll write you and of course, pay for it. Thank you!



No problem. I still don't know why you choose to use 6V6 as a base power tube in Eternity. Having gone through Studio Six which uses 6V6 (and that's a very good tube amp) I find it's not particularly slam full and a force to be reckoned with. Depends on what you want. For refinement and smoothness, 6V6 is good but for slam and 'DRIVE' you want KT88 and above. Just a thought... before it's too late.


----------



## OctavianH

I know what you say and thought about it. But 6V6 is nice and I want to try this. The base grid bias for me wil be KT66 and 6J5 but 6V6 is a nice thought and I really like them in Elise. Of course, it might change but I already have 3 pairs and like them. With the Tube rollind add-on I can use also other outputs so if I fail I can fix it.


----------



## hpamdr (Feb 13, 2021)

Moved from oblivion thread


OctavianH said:


> I have 8 x Philips EL3N like those and I hope I will use them until I die. I never liked them in Elise because the signature was too warm for my taste.


 If you put 4 el3N you have this warm deep sound that UT like that much and the one you seems no not appreciate. (with SET this will be a bit warmer and even more with old school design).

EL3N have almost the same signature as EL11 and 6M6G (No adapter in eternity). EL12Spez / EL12N are more powerful and better stand in output socket. You can drive more easily low-Z can on OTL than EL11/EL3N/6M6.
Synnergy of those on OTL or Glenn 4/6 EL3N inst amp, gives warm sound, large scene  and many euphonic details. It is really a wonderful combo with old pop/folk recording and live jazz.. The best synergy in this area is for me EL11 input and EL12 output. EL11/EL39 is also a very interesting combo i would like to try (@DecentLevi  will probably give us an idea end of next month with his Eternity at home)

If you prefer less signature stick to regular driver/inputs. Only in Power with clean 6J5 or regular 6SN7 you still have warm sound but less emphasis.


----------



## OctavianH

I have to thank you @hpamdr for all your advices and help.

Today I just enjoy music and wonder How Many Tears I have to spend for Eternity. LOL


----------



## hpamdr

OctavianH said:


> I have to thank you @hpamdr for all your advices and help.
> 
> Today I just enjoy music and wonder How Many Tears I have to spend for Eternity. LOL


this is more my cup of tea..and hope that Eternity will not be a never ending story...


----------



## OctavianH

hpamdr said:


> this is more my cup of tea..and hope that Eternity will not be a never ending story...




Your song is excellent. I've listened to it and quite like it. But I have this virus which does not have and not need any antidote which is called heavy metal.

I've watched today several Judas Priest and Halford performances. In this particular one I always waited for that "scream" moment but realized he just not need to do it.
Halford is eternal. Like Eternity!


----------



## OctavianH

hpamdr said:


> If you put 4 el3N you have this warm deep sound that UT like that much and the one you seems no not appreciate. (with SET this will be a bit warmer and even more with old school design).
> 
> EL3N have almost the same signature as EL11 and 6M6G (No adapter in eternity). EL12Spez / EL12N are more powerful and better stand in output socket. You can drive more easily low-Z can on OTL than EL11/EL3N/6M6.
> Synnergy of those on OTL or Glenn 4/6 EL3N inst amp, gives warm sound, large scene  and many euphonic details. It is really a wonderful combo with old pop/folk recording and live jazz.. The best synergy in this area is for me EL11 input and EL12 output. EL11/EL39 is also a very interesting combo i would like to try (@DecentLevi  will probably give us an idea end of next month with his Eternity at home)
> ...



How are you able to know how a combo will sound in an amplifier? I am really curious to know if there is a way to predict this. 
Thanks for the hint about 6M6G, I never heard about them before but they are very interesting. I will definitely try these.


----------



## UntilThen

hpamdr said:


> Moved from oblivion thread
> If you put 4 el3N you have this warm deep sound that UT like that much and the one you seems no not appreciate. (with SET this will be a bit warmer and even more with old school design).
> 
> EL3N have almost the same signature as EL11 and 6M6G (No adapter in eternity). EL12Spez / EL12N are more powerful and better stand in output socket. You can drive more easily low-Z can on OTL than EL11/EL3N/6M6.
> ...



Both EL3N and EL11 make good drivers but my preference is certainly EL11 which has better clarity, details and precision. In Odyssey I'll only be using EL11 of which I have 7 pairs of mostly Siemens, Telefunken, Tesla, etc. I have no intention to roll in EL3N.

In discussions with Tomas, drivers for Odyssey are firming. Will use 2 single triodes (EL11 strapped) and a single double triodes (6SL7 with the ability to run 6SN7 at a lower current if desired - 12au7 a possibility to roll in the 6SL7 socket with an adapter. Now I'm thinking 12AT7 in place of 12au7 for higher gain. I have just found some nice 12AT7s in pairs even though I only need one for Odyssey.


----------



## OctavianH

Thinking about 6M6G I realised that a good and helpful thing for me would be to have a list of parameters which a tube needs to satisfy in order to be usable in our amplifier.
Based on this I can evaluate if a tube might be suitable or not to input/output or both.

I think that those parameters are something like:
- grid bias in a specific range (let's say 0-15V for input and 0-50V for output) strapped as triodes
- plate dissipation under a specific value at the already mentioned operating point
- mu in a specific range

I do not have enough experience to say more, but I guess if we manage to define these, it will help us in the future.
What do you think?


----------



## UntilThen

For visual appeal, Odyssey will be centred on the graphite grey colour of EL11 and EL12 spez. Power tubes of kt88, kt77, kt66 etc will be swapped in occasionally. 6SL7 will add to offer more variations in tone. I think it will all come back to my original 'Berlin' intentions, which is to use EL11 and EL12 spez mainly. I already have those tubes. Chassis can be a metal chassis of similar grey tone, crimson red or wood.


----------



## SonicTrance

OctavianH said:


> Thinking about 6M6G I realised that a good and helpful thing for me would be to have a list of parameters which a tube needs to satisfy in order to be usable in our amplifier.
> Based on this I can evaluate if a tube might be suitable or not to input/output or both.
> 
> I think that those parameters are something like:
> ...


I had a look at the EL33 datasheet which the 6M6G is supposed to be very much alike. You would be able to find operating points for both input and output stage in Eternity for that tube. But it is intended as output.

You're thinking correct regarding the parameters!


----------



## UntilThen

More driver tubes to buy for Odyssey. These are rare beauties, especially the Ediswan and Mullard. That's it after this no more drivers. I have enough !   

Denis, I hate you.


----------



## hpamdr

OctavianH said:


> How are you able to know how a combo will sound in an amplifier? I am really curious to know if there is a way to predict this.
> Thanks for the hint about 6M6G, I never heard about them before but they are very interesting. I will definitely try these.


Unfortunately no exact science until you really listen to it. My guess is that the combo i've tested in F.A will keep the same flavor/Tone in eternity. I could be completely wrong.
About 6MG i have a quad a friend gave me saying that it have a tone like EL3N. Same as EL33 / KT61 (for GEC Lover) usable on EL34 socket !


----------



## mordy

OctavianH said:


> Friday, Beerday, Tube Pr0n day. 6x6v6. Evil combo
> 
> 
> 
> ...


Do you mind identifying your favorite tubes?


----------



## OctavianH

mordy said:


> Do you mind identifying your favorite tubes?



I have not listened yet to all of these. Some of them were bought for the upcoming amplifier. In Elise I tried the GEC KT66 clear glass and I like it very much in the power position. It was the reason I decided to order an amplifier built for the 6V6 tube family. The L63 tubes are new for me but I have high expectations from them.


----------



## mordy

OctavianH said:


> I have not listened yet to all of these. Some of them were bought for the upcoming amplifier. In Elise I tried the GEC KT66 clear glass and I like it very much in the power position. It was the reason I decided to order an amplifier built for the 6V6 tube family. The L63 tubes are new for me but I have high expectations from them.


The L63 tubes have a great reputation. Because of self imposed spending limits I have not yet found a pair at the price I prefer, but possibly I am listening to the L63 sound by using triode strapped Z63 tubes.


----------



## hpamdr (Feb 14, 2021)

mordy said:


> The L63 tubes have a great reputation. Because of self imposed spending limits I have not yet found a pair at the price I prefer, but possibly I am listening to the L63 sound by using triode strapped Z63 tubes.


@OctavianH 
On Elise/Euforia, if you have adapter for 6n7G or ECC31 to 6SN7 you can just plug in place L63 (Same for 6J5 (G, MG)..., *6C5G*). You will get half of 6SN7 single triode with clean and detailed sound. To me it pairs well with anything this is a really great driver/input.
@mordy Z63 i like 6J7 but not sure we have the same familly sound between GEC L63 and Z63 than 6J5 and 6J7. Never tested as i do not have any L63 in my collection


----------



## OctavianH

mordy said:


> The L63 tubes have a great reputation. Because of self imposed spending limits I have not yet found a pair at the price I prefer, but possibly I am listening to the L63 sound by using triode strapped Z63 tubes.



GEC L63 brown base clear glass are easy to find at Langrex for 40 EUR. It is true that starting from January you have to pay 20% more taxes for them because of Brexit. The grey glass ST shaped ones are more expensive, but I could not resist to try a pair.


----------



## UntilThen

OctavianH said:


> How are you able to know how a combo will sound in an amplifier? I am really curious to know if there is a way to predict this.
> Thanks for the hint about 6M6G, I never heard about them before but they are very interesting. I will definitely try these.



There is no way to make such a prediction but...... 

I've endless conversation with Tomas now. I put forth ideas for drivers such as 12au7, 12at7, 6sn7, EL11 and 6sl7 and he gave his advice on all those - which is basically yes they are all suitable, some high gain some less so. 

I also discussed whether it's possible to have both EL11 and 6sl7 running together. His reply was why would you complicate the sound. The amp will work but it will add distortions to it. However that means I have the options to experiment with them together or separately. By 6sl7 I mean all of 6sl7, 6sn7(ecc32, ecc33, b65, etc) and 12au7, 12at7, 12ax7 via adapters on the 6sl7 socket. He added the 'wonders of auto bias'.   

Now we're on the final stretch of the design which includes Yamamoto for all sockets, and he's waiting on a reply from a specialist custom transformer maker for a quote on a windings taps of 8, 50, 100 and 300 ohms. This project is starting to be bigger than Ben Hur.


----------



## UntilThen

mordy said:


> The L63 tubes have a great reputation. Because of self imposed spending limits I have not yet found a pair at the price I prefer, but possibly I am listening to the L63 sound by using triode strapped Z63 tubes.



I was thinking long and hard of adding L63 / 6J5 as drivers to Odyssey but I have too many drivers options at my disposal already and the aim is to keep it simple.... got to draw a line somewhere.


----------



## hpamdr (Feb 14, 2021)

UntilThen said:


> and the aim is to keep it simple.


 KISS !


----------



## OctavianH (Feb 15, 2021)

Your comments regarding L63 and 6J5 are very encouraging. I have to admit that I did not knew that using a 6N7G adapter in Elise I can plug the 6J5 and use half of each 6SN7 slot. I wonder why I have not done this until now. But at the moment I do not want to invest time and resources in Elise anymore, it is a very nice amplifier but he has done his job already and I want to focus on the upcoming one. Thinking about the last 3 Elise years I realize that even if 6SN7 are very expensive, I never liked them more than 7N7 or 6F8G. They cost a fortune and in my opinion are easily surpassed by others, including here Melz 6H12C I tried as drivers and like them a lot. What to say, personal preference.
But Elise and Euforia are amplifiers where we are using tubes in the wrong way, I would say, because I learned later that many of the combos we use there are composed of tubes intended as output. In the upcoming UltraSonic amplifier we will not be able to use these as input and Tomas advised me many times to renounce of my previous ideas and use the tubes as they were intended, because the sound in this way will be much better.


----------



## hpamdr

The comment about adapter was to not invest, just try it in Elise to get a taste. Elise/Euforia works at lower voltage than Eternity/Infinity will. Consider than enjoying in Elise is like burning for eternity...


----------



## OctavianH (Feb 15, 2021)

hpamdr said:


> The comment about adapter was to not invest, just try it in Elise to get a taste. Elise/Euforia works at lower voltage than Eternity/Infinity will. Consider than enjoying in Elise is like burning for eternity...



I'll think about it. The problem is that I do not have such an adapter and for Elise I will need 2. Then from those 2 I will be able to use only one in the Eternity and I have no 6N7 in my collection nor a plan to add some so I might not need them afterwards. But I can do this, you are right. It can be a good starting point with the 6J5.


----------



## UntilThen (Feb 15, 2021)

OctavianH said:


> I'll think about it. The problem is that I do not have such an adapter and for Elise I will need 2. Then from those 2 I will be able to use only one in the Eternity and I have no 6N7 in my collection nor a plan to add some. But I can do this, you are right. It can be a good starting point with the 6J5.



I won't use 2 x L63 with adapter in Odyssey 6sn7 socket because if I wanted to use L63 / 6j5, I would have ask Tomas to incorporate it. I want the amp to have a clean and smart look and I'm not interested in rolling every tube under the sun. So it's a choice of 2 x 6j5 or 2 x EL11 and because I already have 7 pairs of NOS nib pairs of EL11, I went with that - also from my previous experience with EL11 and EL12 spez, that could be one of the best combination I've ever experience in tube rolling. The combination of details, clear extended treble without the edginess, solid tight bass and forward sounding mids plus the great looks of those 4 grey tubes together helps me with the decision.

My seller has a lot of 6sl7 and 12au7, 12at7, 12ax7. He described the 12xx7 as being clear, sweet, tight and extended while the 6sl7 / 6sn7 has a fuller tone. I can see how I would use those tubes as well as EL11.

Then of course there are those various power tubes that will provide the force and slam, also refinement and romantic when call for in the EL34. EL12 spez is as expected of Telefunken, a brighter and clearer tone than the Mullard EL34. A very good contrast.


----------



## hpamdr

UntilThen said:


> I won't use 2 x L63 with adapter in Odyssey 6sn7 socket because if I wanted to use L63 / 6j5, I would have ask Tomas to incorporate it. I want the amp to have a clean and smart look and I'm not interested in rolling every tube under the sun. So it's a choice of 2 x 6j5 or 2 x EL11 and because I already have 7 pairs of NOS nib pairs of EL11, I went with that - also from my previous experience with EL11 and EL12 spez, that could be one of the best combination I've ever experience in tube rolling. The combination of details, clear extended treble without the edginess, solid tight bass and forward sounding mids plus the great looks of those 4 grey tubes together helps me with the decision.
> 
> Then of course there are those various power tubes that will provide the force and slam, also refinement and romantic when call for in the EL34. EL12 spez is as expected of Telefunken, a brighter and clearer tone than the Mullard EL34. A very good contrast.


 No one should use 2x 6J5 (L63....) to 6SN7 socket except in single tube amp.
Will you have 2x 6J5, 2x EL11, 1 x 12ax7, 1 x 6SL7 sockets in input and 2x EL12, 2xEL34 in output side or will you use EL11 -> 6J5 and EL12 -> EL34 adapter, 12Ax7 -> 6SL7 adapter ?

About 12at7 (gain 60), 6SL7 (gain 70) and 12ax7(gain 100)...For high mu/gain tube, you need a well built amplifier to avoid noise. Tomas use 6AV6 triode side gain is 100 so he know what to do ! I also like smaller 9 pin tube like E188CC or 6922 or 6N30P-(DR/EB/EV) really detailed and refined with wonderful and precise high (Soprano voice). I also like a small tube that will not fit due to max voltage (100V) EC86...It was already on/over the limit inF.A. amps.


----------



## UntilThen (Feb 15, 2021)

@hpamdr I am leaving it to Tomas. He knows what to do.

Meanwhile I await the arrival of Auralic Taurus Mk2.


----------



## UntilThen (Feb 15, 2021)

hpamdr said:


> No one should use 2x 6J5 (L63....) to 6SN7 socket except in single tube amp.
> Will you have 2x 6J5, 2x EL11, 1 x 12ax7, 1 x 6SL7 sockets in input and 2x EL12, 2xEL34 in output side or will you use EL11 -> 6J5 and EL12 -> EL34 adapter, 12Ax7 -> 6SL7 adapter ?
> 
> About 12at7 (gain 60), 6SL7 (gain 70) and 12ax7(gain 100)...For high mu/gain tube, you need a well built amplifier to avoid noise. Tomas use 6AV6 triode side gain is 100 so he know what to do ! I also like smaller 9 pin tube like E188CC or 6922 or 6N30P-(DR/EB/EV) really detailed and refined with wonderful and precise high (Soprano voice). I also like a small tube that will not fit due to max voltage (100V) EC86...It was already on/over the limit inF.A. amps.



Sorry didn't reply to this last night as I was tired and went to bed.

Odyssey tubes layout as I envisage them. Doing this to let you know what tubes will be use in it. 6J5 is not part of it. I'm not using it. Not that they are bad but I wanted to keep it neat and tidy. In fact initially I was thinking of only a pair of drivers.


KT88, EL34, etc  ---------  GZ34, etc  -----------  KT88, EL34, etc
|
|    
........   EL11   ----------------   6SL7  -------------------   EL11
.....................................(can use 6SN7)
..............(can use 12AU7, 12AT7, 12AX7 with adapter)


Unlikely that I will use 12ax7 but I'll try it. I was thinking of using 6J5 in the spots of EL11 but decided that I prefer the EL11 as I had bought a lot of EL11 and EL12 spez about 3 years ago for a custom amp to be named 'Berlin' - in reference to the Telefunken / Siemens tubes. This was what I had in mind then. No tube rolling option but very smart and clean look. No adapters required as I would have stipulated EL12 spez sockets with top cap be installed.


EL12 spez   ----------  GZ34  -------------  EL12 spez
|
|
..................EL11   --------------------       EL11


----------



## OctavianH (Feb 16, 2021)

Guys, we have stuff to do: Tung-Sol KT170

The Tung-Sol KT170 has a power dissipation of 85 watts allowing amplifiers using a pair of these tubes to reach power output levels in excess of 300 watts.

Later Edit: I found the specs here.


----------



## UntilThen (Feb 16, 2021)

Nah too big for me.  Ain't having a stereo amp build to drive tower Dynaudio. 

It does have a very shape though.


----------



## OctavianH

UntilThen said:


> Nah too big for me.   Ain't having a stereo amp build to drive tower Dynaudio.



I definitely do not need it but it looks so nice, like an 1950 Buick.


----------



## UntilThen

Some new development on Odyssey. First of all, to blend in the colour of EL11, I might be going for a silver chassis like the Citadel. Secondly, enquiries have been made to the UK specialist transformer maker Sowter. They are as famous as Lundahl. The transformers are also silver in colour and I'm debating whether to leave them naked for an old school tube amp look or have covers to shield them. Thoughts anyone? 

3 transformers line up at the back of the chassis. Should be good.


----------



## UntilThen

OctavianH said:


> I definitely do not need it but it looks so nice, like an 1950 Buick.



I want my amp to look like that !


----------



## hpamdr (Feb 16, 2021)

UntilThen said:


> 3 transformers line up at the back of the chassis. Should be good.


The nacked transformer are nice but to it is matter of taste. https://www.flickr.com/photos/39959182@N05/50529326807/in/photostream/lightbox/
I've seen some amplifier with chromed transformer cover. I do not know if it is original witch are chromed afterward (like for the buick renovated part) or optional...  (integrated amplifier Diapason from Jadis)
Those one have only half of the transformer visible...


----------



## UntilThen

hpamdr said:


> The nacked transformer are nice but to it is matter of taste. https://www.flickr.com/photos/39959182@N05/50529326807/in/photostream/lightbox/
> I've seen some amplifier with chromed transformer cover . I do not know if it i original with are chromed afterward (like for the buick renovated part) or optional...  (integrated amplifier Diapason)
> Those one have only half of the transformer visible...



Yes it can look good. Tomas showed me a sample with Citadel with naked silver transformer and I think it look great.


----------



## OctavianH

Just found a document with different tube pinouts. I guess it is interesting, I think I'll put a link at resources in the 3rd post.


----------



## hpamdr (Feb 17, 2021)

I'm using the RCA book and next or huge old one. for tube reference. (but Radiomuseum  or Frank's electron Tube database are the most reliable sources.)
About socket, for UK/European valve base this is the one with all drawing just if you want technical and mechanical information.
*If someone have a Russian / Western tube equivalence table this would be great to share ( Specially if it is in English )*


----------



## OctavianH (Feb 17, 2021)

hpamdr said:


> I'm using the RCA book and next or huge old one. for tube reference. (but Radiomuseum  or Frank's electron Tube database are the most reliable sources.)
> About socket, for UK/European valve base this is the one will all drawing just if you want technical and mechanical information.
> *If someone have a Russian / Western tube equivalence table this would be great to share ( Specially if it is in English )*


This is quite great stuff. I knew already the Radiomuseum and Frank's db but the others are new to me. Indeed, much better that that simple PDF. Thanks for sharing.
Instead of using these kind of manuals I was using in the past the TDSL personal edition. A small software which can be downloaded from here.



You can find here a lot of Datasheet links and some substitutes. For noobs like me it is perfect.

PS1. Beware that this software is old, it does not make a shortcut in the installed list, so you need to search and open it from the disk directly everytime. But you can pin the exe to Start to help you.




PS2. I think they've made also an android .apk for it to use it on your mobile phone but I never tried that. Could be useful.

@hpamdr : I found this table which might be of help for russian equivalents. (source)


----------



## UntilThen

Got another pair of EL34 - this is RFT from East Germany. Original box and very a sweet tone and it's only AUD $169. It's a steal. Seller is a friend and he had only a few hours with it and it's NOS.
Shown here with the Philips Miniwatt 6CA7. Both pairs are quiet and such clarity and euphony. I'm sold on EL34 and all it's variants.


----------



## OctavianH

Offtopic, but interesting:
Sennheiser is open to selling its consumer audio business


----------



## hpamdr

UntilThen said:


> Got another pair of EL34 - this is RFT from East Germany. Original box and very a sweet tone and it's only AUD $169. It's a steal. Seller is a friend and he had only a few hours with it and it's NOS.
> Shown here with the Philips Miniwatt 6CA7. Both pairs are quiet and such clarity and euphony. I'm sold on EL34 and all it's variants.


So now you can give a look to EL84 and variants..


----------



## UntilThen

hpamdr said:


> So now you can give a look to EL84 and variants..



Nope that's not in my radar. There are a lot of very good tubes including the EL84 but I think I have to have a plan. Draw a perimeter of driver and power tubes type and stay with it.


----------



## OctavianH

Too dark isn't it? I bet the VU meters of Eternity would help


----------



## OctavianH

I started to burn in some PsVane KT88T2. I plan to use these on Eternity when it will arrive. See you in around 200 hours.


----------



## hpamdr

OctavianH said:


> I started to burn in some PsVane KT88T2. I plan to use these on Eternity when it will arrive. See you in around 200 hours.


Nice grey and gold suit. 
Did you paint yourself the volume step of your Elise ? 
_I personally did the opposite and used a small file to have a visible/sensitive cursor on the pot._


----------



## OctavianH (Feb 22, 2021)

hpamdr said:


> Nice grey and gold suit.
> Did you paint yourself the volume step of your Elise ?
> _I personally did the opposite and used a small file to have a visible/sensitive cursor on the pot._



Yes, PsVanes look nice and are quite good tubes. I think the drivers are the only new production tubes I liked on Elise. But besides the sound which pleases me and it is a very good partner for Tung Sol 5998, these have a very good build quality, aluminium base with ceramic inside, good heat dissipation.

And yes, I painted the lines of Elise with a white marker, to be able to see the volume better in low light.

PS. I think I'll have a look on the gain of 6SN7 + KT88 vs KT66 + 6L6 because I have to put the volume around 60% with these compared to the others.

PS2. These get much hotter than the KT66, around 100C.


----------



## hpamdr

OctavianH said:


> PS. I think I'll have a look on the gain of 6SN7 + KT88 vs KT66 + 6L6 because I have to put the volume around 60% with these compared to the others.
> 
> PS2. These get much hotter than the KT66, around 100C.


Same at home, KT88 get hot.. But still less than 5998 or 6080.
About 6L6 I'm pretty sure we will not be able to use it as input tube.


----------



## OctavianH

hpamdr said:


> Same at home, KT88 get hot.. But still less than 5998 or 6080.
> About 6L6 I'm pretty sure we will not be able to use it as input tube.



Thinking about how hot are these KT88 I guess the sockets of Eternity, mounted above the top panel will help compared with Elise where the sockets are somehow under it.


----------



## UntilThen

Bought this adapter in preparation for Odyssey.


----------



## hpamdr

UntilThen said:


> Bought this adapter in preparation for Odyssey.


Nice looking (_chinese_) adapter... Just have to wait


----------



## OctavianH

I am afraid to go on the "small tubes" path. I try to keep things simple. I guess 6SN7 and 6J5 are enough for me as inputs, because I am not sure that this new design will be very responsible to rolling on inputs. I have a feeling that a fixed grid bias for inputs is enough and output rolling might produce the best results, but we will know this for sure when Levi's Infinity will be ready and he will be able to make some tests.

My Eternity will allow me to populate all 3 input slots at the same time, I will have an input switch, but the switch will only connect/disconnect the plate and grid. The tube will sit there, light (heater connected always) but will not draw current. Because I consider that also the heater might wear off unnecessarily I will populate the 6SN7 slot most probably with a cheap and nice lighting tube, or one I have several pieces. I know that, most probably, the tube will be fine for ages but anyway. And I have only pairs of tubes except one pairless Foton 6H8C '55. The reason is that I broke one when I was rolling in Elise. I had in total 10 pieces. 2x'53, 4x'55 and 6x'77. Soundwise, there was a bigger difference between pre-'55 and newer. So I sold those 6 pieces from '77 when I sold Little Dot as a bundle. The pair of '53 I gave to a friend and now I have 3 x '55. One of them will light in Eternity, grieving its missing pair for eternity.


----------



## hpamdr

One of the issues i have seen with some russian tubes and specially the one after 70' is the unbalanced triode. On my small CTH (Singl Tube Amp) i can hear the missmatch. I was using a small tube-tester to verify that both triode have almost same emision. 
One triode much stronger than another is really not an issue with Elise as both are strapped into one. With Eternity as we use only one triode by side this default should have more importance.


----------



## OctavianH

I have read about such issues related to russian tubes. Indeed, now we will see the truth.
By the way, has anyone experience with this kind of products?






I think I need to practice my french skills a bit.


----------



## hpamdr

This kit is a all in one tube tester good for the buck. Unfortunately it does not include testing plate/socket case ... (This is the time consuming part when you build it). You can see the complete range on his website.
Alain Ducrocq is a very nice Guy and usually ready to help. (if French is an issue, i can help )


----------



## OctavianH

hpamdr said:


> This kit is a all in one tube tester good for the buck. Unfortunately it does not include testing plate/socket case ... (This is the time consuming part when you build it). You can see the complete range on his website.
> Alain Ducrocq is a very nice Guy and usually ready to help. (if French is an issue, i can help )



Thanks! I've made 4 years of french in high school, now we will see if they were in vain or not. I am intersted in a modern tube tester, if possible pre built.


----------



## hpamdr

OctavianH said:


> Thanks! I've made 4 years of french in high school, now we will see if they were in vain or not. I am intersted in a modern tube tester, if possible pre built.


So the mounted one is for you !  (you can ask if it embed new duovac 3 board).

It does not embed a curve tracer but is very flexible and more than enough for bias measurement. You can get all tube parameters. For KT, EL, ...., If you want to strap as triode just use 2 additional connection cables, build one inserting a 100R resistor to strap G2 and A in tube part (1,2,3,....) black plugs, and another normal one from K to G3 (if not already internally wired) and then go to measuring plug as described for simple triode.


----------



## OctavianH (Feb 26, 2021)

Interesting, now I study the differences between those 2 ones (the one with 850 EUR vs the one with 440 EUR). The measuring method is different it seeems (dissipation vs impulse). A very interesting product, not cheeap, I have to think if it makes sense to go on this path or not.

Later edit: I think G3 and K are already internal wired:


----------



## UntilThen

hpamdr said:


> Nice looking (_chinese_) adapter... Just have to wait


The last chinese adapters (el12 to kt88) arrived within 2 weeks.


----------



## hpamdr

OctavianH said:


> Interesting, now I study the differences between those 2 ones (the one with 850 EUR vs the one with 440 EUR). The measuring method is different it seeems (dissipation vs impulse). A very interesting product, not cheeap, I have to think if it makes sense to go on this path or not.
> 
> Later edit: I think G3 and K are already internal wired:


You are right it is wired in measuring part and in many tube this is also wired internally but it is for me easier to keep it separated.

You have to strap triode on the tube pin/plug (1,2,3,.......) part at least for A/G2 +100R, optionally K+G3.

Then connect to measuring cable to Plate (A + 10RG2), G1,  K.


----------



## OctavianH

I will have to read more about this until I fully understand but I do not see an user manual for this device. Ok, I know that I do not have enough experience, but a measuring example would be useful for noobs like me. The black plugs 1->9 from the first row are corresponding to the tube pins from the VT1 and VT2 sockets (for VT2 the first 8). The second row are measuring points? You mention something but it was not clear to me. I thought the second row is to realize connection for each type of tube you insert into the socket. 

For example for 6V6, from my understanding:

I follow pinout of 6V6 and connects pins 1->8 to the corresponding Plate/Cathode/Grids/Heaters from row 2. 
Then strapping as triode with 100Ohm resistor Plate with G2. Right?





After that I just select 6.3V and turn it on with the 6V6 inserted in VT2. Not clear to me what I do with these:





PS. I know I am a noob, but I try to fix my know how. Thanks a lot for help guys.


----------



## hpamdr (Feb 26, 2021)

*Almost ok *
Resistor from  pin 3 (A) to 4 (G2)   
In strapped mode, you do not use G2 so what you have to connect is G1 to pin 5.

Then:

With trim plate you adjust 200 or 180 or whatever plate Voltage.
Let trim G2 to null
Use trim 1 to find negative voltage that will match 20ma for output or 4ma for input reading measured current on screen.    

(Some variation may occurs to not go above tube specs EL32 case)


----------



## OctavianH (Feb 26, 2021)

So you say like this?





It is clear to me that G1 has to be connected to 5. But it is not clear why the resistor is connected to pin 4 which as far as I know is not used by 6V6.

What trimmers mean is clear to me now, so with Vg1 = 0 I start the tester and then manually rise it until the current matches the value from the operating point and in this way I determine the grid bias voltage? (somehow similar with the trimmers on the amplifier).

But how are you measuring tube health?

PS. I know I am the worst student, this is why I switched to software from hardware, at least the build crashes and you are not letting the smoke outside the components. You know how electrical components work, with smoke, when you broke them the smoke goes out and they stop functioning. Been there, done that.


----------



## hpamdr

I'm also in the software part since many.....years 

6V6 pin 4 is G2 unless i got wrong schema...
For Grid voltage, you can start from 0 and decrease of from the lower value for your tube and increase. 

To measure tube health, you have to use tube datasheet and compare your tube measures to the "official value".  _(You can also get a tube tester manual with many tube described and the good/bad values)_


----------



## OctavianH

hpamdr said:


> 6V6 pin 4 is G2 unless i got wrong schema...



You are right, I was looking to a wrong schema! Incredible! Brrrr. Now everything seems clear. Thanks a lot!


----------



## UntilThen

@SonicTrance  can I use this in Odyssey ?  Or this might be for another project....   

https://www.ebay.co.uk/itm/31342975...&buyerid=OT1C29eGPzQ qD9nQ2vYrw==&refid=store


----------



## UntilThen

Huh there's even an adapter for it.
https://www.ebay.com.au/itm/1pc-Gol...rand=Unbranded&_trksid=p2047675.c101195.m1851


----------



## hpamdr

UntilThen said:


> @SonicTrance  can I use this in Odyssey ?  Or this might be for another project....
> 
> https://www.ebay.co.uk/itm/313429750175?ViewItem=&item=313429750175&category=0&ssPageName=ADME:B:SEMK:UK:SHOWI&emailtemplateid=145438856&sellerid=FpRekKD1aqAWsCi2/SAKqA==&buyerid=OT1C29eGPzQ qD9nQ2vYrw==&refid=store


You want it BIG...
You can get curve at diy Attitube. If i read correctly this should be OK (-12.5V) for Bias but do not know about impedance matching in your case.


----------



## UntilThen

How about this?  lol  now we're going big guns   
https://www.ebay.com.au/itm/1pc-GU-...rand=Unbranded&_trksid=p2047675.c101195.m1851

https://www.ebay.com.au/itm/2pcs-GU...iseUnbiasedWeb&_trksid=p2047675.c101195.m1851


----------



## OctavianH

My wallet just called me, told me to leave this thread. LOL


----------



## hpamdr (Feb 26, 2021)

UntilThen said:


> Huh there's even an adapter for it.
> https://www.ebay.com.au/itm/1pc-Gold-plated-Telefunken-EL156-TO-KT88-tube-converter-adapter/201357485488?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20201210111314&meid=d70ffc3da64d4c3cbd2a5764df6143f9&pid=101195&rk=6&rkt=12&mehot=sb&sd=313429750175&itm=201357485488&pmt=1&noa=0&pg=2047675&algv=SimplAMLv9PairwiseUnbiasedWeb&brand=Unbranded&_trksid=p2047675.c101195.m1851


Without adapter you can try to get EL156B but 
// edit made in China.....


----------



## UntilThen (Feb 26, 2021)

My wallet is just getting a warm up.
https://www.ebay.com.au/itm/Osram-Brimar-12AT7-b309-ecc81-black-plate-45-Degree-Square-Getter-NOS-Balanced/164614930339?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20201210111314&meid=4f0a270323ad46c9964278867d7da580&pid=101195&rk=2&rkt=12&mehot=pf&sd=164637611680&itm=164614930339&pmt=1&noa=0&pg=2047675&algv=SimplAMLv9PairwiseUnbiasedWeb&brand=Brimar&_trksid=p2047675.c101195.m1851

https://www.ebay.com.au/itm/Philips...&brand=Philips&_trksid=p2047675.c101195.m1851


----------



## UntilThen

Tubes are going to kill me again.  
https://www.ebay.com.au/itm/GEC-U52...motedViewItems&_trksid=p2047675.c100752.m1982

However, with this solid state of Auralic Taurus Mk2 and Bifrost 2 and the skull, I wonder why I am chasing tubes... This is so good. I should keep the Taurus.


----------



## OctavianH

UntilThen said:


> Tubes are going to kill me again.
> https://www.ebay.com.au/itm/GEC-U52-5U4G-Black-Plate-Black-Base-Cup-Getter-NOS/164290806367?_trkparms=aid=555023&algo=HOMESPLICE.SIMRVI&ao=1&asc=20210125104017&meid=ca033afcb1494967bf3dcd66893e23da&pid=100752&rk=2&rkt=24&mehot=pf&sd=265057763533&itm=164290806367&pmt=1&noa=0&pg=2047675&algv=SimplAMLv5hPointwiseWebNoToraCoCoViewsNoHighIdfOrRoundRobinBlenderWithPromotedViewItems&_trksid=p2047675.c100752.m1982



By the way, I've seen several times GEC tubes sold from Vietnam or Pakistan. Are these sellers reliable or scammers?


----------



## UntilThen

OctavianH said:


> By the way, I've seen several times GEC tubes sold from Vietnam or Pakistan. Are these sellers reliable or scammers?


They are legit. I bought tubes from the seller in India. That seller in Hanoi has a lot of good tubes but like everyone else, the price is better than good.


----------



## hpamdr

UntilThen said:


> Tubes are going to kill me again.
> https://www.ebay.com.au/itm/GEC-U52-5U4G-Black-Plate-Black-Base-Cup-Getter-NOS/164290806367?_trkparms=aid=555023&algo=HOMESPLICE.SIMRVI&ao=1&asc=20210125104017&meid=ca033afcb1494967bf3dcd66893e23da&pid=100752&rk=2&rkt=24&mehot=pf&sd=265057763533&itm=164290806367&pmt=1&noa=0&pg=2047675&algv=SimplAMLv5hPointwiseWebNoToraCoCoViewsNoHighIdfOrRoundRobinBlenderWithPromotedViewItems&_trksid=p2047675.c100752.m1982
> 
> However, with this solid state of Auralic Taurus Mk2 and Bifrost 2 and the skull, I wonder why I am chasing tubes... This is so good. I should keep the Taurus.


Or should sell taurus and get Jothuneim II to have a new piece of schiit.
You are diverging from the Berlin concept.. Simple and built to use the tube you already own


----------



## OctavianH

Friday. Beerday. Just realized that in this light the base of my Psvanes looks almost the same as my beer. LOL






First world problems. To beer or not to beer, that was the real question.


----------



## UntilThen

hpamdr said:


> Or should sell taurus and get Jothuneim II to have a new piece of schiit.
> You are diverging from the Berlin concept.. Simple and built to use the tube you already own


Had a Jotunheim before. This Taurus is a classy act. The sound is great !

Yeah I know - Berlin. However now I'm in danger of not hearing back from Yamamoto and jacmusic. They are slack and don't respond to emails. 

Simple and built to use the tubes I already own is a mirth. My tubes collection for Odyssey has just begun. I've yet to buy the GEC KT77, KT88 and Tung Sol 6550 that is waiting for me. After that I can stop with power tubes while I focus on some good 6SL7, 6SN7, 12au7, 12at7 and 12ax7. Then some more rectifiers and I'm done. Not too much not too little.


----------



## UntilThen

The new arrival Kenwood KA 3300D has just join the rack and it's muscular at 150w rms into 8 ohms. Look at the size of the transformer.


----------



## UntilThen

Theme song for Berlin and it will still be the theme song for Odyssey. It's my dream coming to fruition. An amp 3 years in the making and planning.


----------



## jonathan c

OctavianH said:


> Friday. Beerday. Just realized that in this light the base of my Psvanes looks almost the same as my beer. LOL
> 
> 
> 
> First world problems. To beer or not to beer, that was the real question.


The Psvanes, and not your stein, should have the vacuum...


----------



## SonicTrance

UntilThen said:


> @SonicTrance  can I use this in Odyssey ?  Or this might be for another project....
> 
> https://www.ebay.co.uk/itm/313429750175?ViewItem=&item=313429750175&category=0&ssPageName=ADME:B:SEMK:UK:SHOWI&emailtemplateid=145438856&sellerid=FpRekKD1aqAWsCi2/SAKqA==&buyerid=OT1C29eGPzQ qD9nQ2vYrw==&refid=store


Yes! Looking at the triode curves it'll run pretty cool in Odyssey. Looks to be a nice tube!


----------



## OctavianH

UntilThen said:


> Theme song for Berlin and it will still be the theme song for Odyssey. It's my dream coming to fruition. An amp 3 years in the making and planning.




In this case you need to renounce on your Rolls Royce and use a F18 Hornet.


----------



## UntilThen

SonicTrance said:


> Yes! Looking at the triode curves it'll run pretty cool in Odyssey. Looks to be a nice tube!


Yes ! More tubes to buy.


----------



## UntilThen

OctavianH said:


> In this case you need to renounce on your Rolls Royce and use a F18 Hornet.


At the rate I buy stuff, I can't even afford a toy model F18 Hornet.

This morning I pick up a pair of Siemens 12AT7 and quad Vibrapods Model 4 for Odyssey. That should give me some good vibrations.


----------



## OctavianH

UntilThen said:


> This morning I pick up a pair of Siemens 12AT7 and quad Vibrapods Model 4 for Odyssey. That should give me some good vibrations.



I think the amplifier will aready have anti-vibration pads like the Infinity on the website. Why do you need those Vibrapods?


----------



## UntilThen

For more vibrations !  If not, it can go on my many other amps or turntable.


----------



## OctavianH

A pair of EL33/6M6G/EL37 would be something interesting. But the prices on Ebay are crazy.





Well, the simple solution would be a pair of EL3N -> 6V6 adapters and that's it. I have EL3N for my whole life and I doubt I'll ever listen to them again.


----------



## UntilThen

OctavianH said:


> A pair of EL33/6M6G/EL37 would be something interesting. But the prices on Ebay are crazy.
> 
> 
> 
> Well, the simple solution would be a pair of EL3N -> 6V6 adapters and that's it. I have EL3N for my whole life and I doubt I'll ever listen to them again.



Me thinks you should get yourself some EL11 unless your preference are completely different from mine. EL11 is clearer, more details and has better high end extension. Bass is also tighter and with greater impact. I started with EL3n but once I got onto EL11, I never did return to EL3N.


----------



## OctavianH

I have EL11, always considered EL3N/EL11 too warm for my taste, but thinking that Eternity will be more towards a neutral sound I start to think about warming it a little bit.


----------



## UntilThen

How can EL11 be too warm. I find KT66 warmer than EL11. That is when I use EL11 as power tubes in Glenn OTL. EL3N warm yes but never EL11. Those Telefunkens / Siemens have a distinctly treble uplift and an over brighter tone. Similarly for the EL12 spez.


----------



## UntilThen

OctavianH said:


> I have EL11



You have some very nice EL11 btw. The Valvo ones are definitely the same as my Siemens branded ones.


----------



## OctavianH

UntilThen said:


> You have some very nice EL11 btw. The Valvo ones are definitely the same as my Siemens branded ones.



Yes, but all have a different shape. Who knows, maybe in the future I will buy an identical pair. However they sound identical, so except the visual difference they are nice.


----------



## hpamdr

UntilThen said:


> How can EL11 be too warm. I find KT66 warmer than EL11. That is when I use EL11 as power tubes in Glenn OTL. EL3N warm yes but never EL11. Those Telefunkens / Siemens have a distinctly treble uplift and an over brighter tone. Similarly for the EL12 spez.


The EL11 are on Elise/Euforia are warmer than PSVane 6SN7. But for sure if you use them as driver and EL39 or EL12N or EL11 even EL3N in power they give their full potential. _(I did not found EL12Spez in my budget_) Dynamic, clear on the highs, tight an much more precise than EL3N on BASS, with some emphasis (much less than EL3N) and very musical for sure.  

I have some strait black bottle telefunken which i like more than ST shaped grey RFT or Valvo (But this is my taste).


----------



## UntilThen

hpamdr said:


> Dynamic, clear on the highs, tight an much more precise than EL3N on BASS, with some emphasis (much less than EL3N) and very musical for sure.


That's what I'm looking for or what my ears would like to hear. 

I did not buy any straight Telefunken EL11s because I could not find new ones and I'm OCD in looks... unless I wear eye patches while listening to music.


----------



## OctavianH (Feb 27, 2021)

UntilThen said:


> How can EL11 be too warm. I find KT66 warmer than EL11. That is when I use EL11 as power tubes in Glenn OTL. EL3N warm yes but never EL11. Those Telefunkens / Siemens have a distinctly treble uplift and an over brighter tone. Similarly for the EL12 spez.



You are right that these are different, but for me both were, more or less, warm. EL11 is superior, without doubt, to EL3N. However, I plan to renounce on all exotic sockets, top caps and problematic tubes, so I will focus from now on only on octal socket tubes without top cap. This is why EL33/6M6G is interesting for me, seems same signature as EL3 but with octal socket. I am tired of adapters, I am tired of cleaning paint from tubes from my amplifier or using glue because the top cap went off when I removed the adapter. I want simple things. EL33 seems to work in Eternity without any need of an adapter.


----------



## UntilThen

OctavianH said:


> You are right that these are different, but for me both were, more or less, warm. EL11 is superior, without doubt, to EL3N. However, I plan to renounce on all exotic sockets, top caps and problematic tubes, so I will focus from now on only on octal socket tubes. This is why EL33/6M6G is interesting for me, seems same signature as EL3 but with octal socket. I am tired of adapters, I am tired of cleaning paint from tubes from my amplifier. I want simple things. EL33 seems to work in Eternity without any need of an adapter.


But EL33 will still drip red paint like blood all over your amp lol. That's what I hate about those cheap paint job on those red tubes. They flaked and fall off and then they look real ugly.


----------



## OctavianH

UntilThen said:


> But EL33 will still drip red paint like blood all over your amp lol. That's what I hate about those cheap paint job on those red tubes. They flaked and fall off and then they look real ugly.



Yes! This is what I just realized. LOL Anyway at least no "bathtub" socket or adapters who break. But there are models without red paint. Still the prices are crazy.


----------



## DecentLevi

@UntilThen quoting you from the Ultrasonic Studios thread so we're on topic here instead.
_Yeah I know and you have 8... I'm so jealous !

Btw Tomas, today I tried Telefunken EL12 spez in a proper amp for the first time in my life. It was a 'wow' moment. I can't see how this tube is functioning properly in Elise when I was trying it there. I can see this tube being 'explosive' in Odyssey and it's not even burn in yet. These adapters were ordered from China (mrsxuling) and arrived today in less than 2 weeks.

This is my Gemini twins of TU-8500 (tube preamp / phono stage) + TU-8200 (headphone and speakers amp).

@DecentLevi  for your eyes.

Now I'm tempted to go 4 x EL34 so I can roll 4 x EL12 spez too or 4 x KT88._



Wow those EL12 Spez must've sounded excellent when ran optimally. I knew there was something quite special with their performance on the F.A. amps, but how did it differ here? And I think you have the Tungsram or other brands to try too?

Also that's interesting you have Kenwood integrated amp. Not sure if you noticed my posts a while back but I happened to randomly chance upon a model VR-406 from them. It ain't pretty and it's huge and with a fussy digital volume knob, but its' performance makes up for all of that a million-fold! I have been getting astonishing performance from it as a headphone amp that for me completely eclipses ALL other previous incarnations of my audio journey, BAR-NONE. Makes my Quad PA One + headphone amp sound like child's play, which was already leaps better than all other F.A., Garage1217, etc. amps that came before it. Bass and dynamics kick with a force to be reckoned with, huge soundstage, etc. No complaints on the sound. Though it is a 5.1 speaker amp and I'm still interested in tube amps, hence why I'm in the running for an Infinity amp. My Kenwood is from the early 2000's and I guess yours was from the late 80's. Did you compare it as a headphone amp to your others?

What about the  Auralic Taurus Mk2, is that your favorite SS headphone amp?

And I heard you're upgrading your Yggy DAC. Will it be the same as the new v2?

PS- I've been deeply engulfed with new career paths recently and still backlogged on catching up with the flury of happenings on the Ultrasonic threads.


----------



## hpamdr

@DecentLevi  I hope that those tubes will sound great also in infinity and eternity !
You are on the top for building queue and the first to get an infinity🥇._ I'm almost as  exited as you waiting for your listening experience_.


----------



## DecentLevi (Mar 1, 2021)

UntilThen said:


> There's a new development which will interest me and particularly @DecentLevi or anyone else who loves EL11.
> 
> 2 x EL11 will be use as drivers in Odyssey. They will be on each side of a single 6sn7 double triode. 12au7 via adapter will also be used in the 6SN7 slot.
> 
> ...





UntilThen said:


> Ok I'll chime in. I know of 2 amps that use KT88 and one amp that use both.
> 
> Elekit TU-8200 uses both KT66 and KT88 and many other tubes. Odyssey will as well that's why I'm so excited. Believe me, TU-8200 is so good ...so good...so goood.. ok you get the idea?
> 
> ...


You should be able to also use 6J5 / 6C5 / L63 with two single adapters in the EL11 sockets.

Interesting, I'm not familiar with KT90, 6550, 807 and KT120. Those should work with my custom Infinity amp also, something @SonicTrance would know.


hpamdr said:


> @DecentLevi  I hope that those tubes will sound great also in infinity and eternity !
> You are on the top for building queue and the first to get an infinity🥇._ I'm almost as  exited as you waiting for your listening experience_.


Yup I'm 1st in the queue for an Infinity. But as my financial luck goes, seems my payment installments might put me in the 2nd or 3rd place, even though mine was the first conceived. Luckily Tomas is understanding of the delay which is not his fault. If Glenn could have processed my refund AT ALL as requested last year I wouldn't be in this boat.


----------



## OctavianH

DecentLevi said:


> Interesting, I'm not familiar with KT90, 6550, 807 and KT120. Those should work with my custom Infinity amp also, something @SonicTrance would know.



KT90, KT120 and 6550 work natively. For 807 you need an adapter like this one.

I am very sorry to hear about your problems, let's hope they will be solved.


----------



## UntilThen

DecentLevi said:


> Wow those EL12 Spez must've sounded excellent when ran optimally. I knew there was something quite special with their performance on the F.A. amps, but how did it differ here? And I think you have the Tungsram or other brands to try too?



DL so many different questions that I've to break it up into different segments.  However it's ok I'll answer them all. Tomas did an excellent job answering my 101 questions, so I should also do the same for others if I can answer it.

I have Telefunken EL12 spez x 3 pairs. One pair is bigger than the other 2 identical pairs in original Telefunken boxes. I'm going to test out the 2 different size Telefunken EL12 spez and see if there are any differences in sound. I also have a pair of Tesla EL12 spez with black glass and it's beautiful. However there is one tube that is humming loudly. I may have to buy another Tesla EL12 spez to replace it.

Now how does it differ from Euforia or Elise? Well for one, the drivers used are different in both amps so it's no surprise that they are very different in tone. In Euforia, I use EL11 as drivers with EL12 spez as power tubes. In Elekit TU-8200, I use Brimar 12au7 long plates and Telefunken EL12 spez. Of course in the TU8200, the amp is near bias for EL12 spez as it's bias for EL34. In Euforia, the amp is bias for 6SN7 and 6as7 / 6080. I did not expect magical things from Euforia with EL12 spez. It did sound good but until heard the EL12 spez in TU-8200, I could not believe how good the EL12 spez is. In Odyssey, I expect it to perform even better because Tomas will pay attention to the EL12 spez for me and I can use EL11 as drivers.

In the Elekit TU8200 with 12au7 and EL12 spez, micro and macro dynamics are something I've not heard before and what do I mean by that? Rather than explain, I refer you to this wonderfully written article on micro and macro dynamics. https://miloburke.com/blogs/personal-blog/posts/micro-dynamics-and-macro-dynamics

Details swims around my head. Music sound real and dynamics show it's true colours by making me aware of the soft and loud passages clearly. Treble has just the right extension and sweetness without making me want to yank the headphone from my head. I'm able to listen for hours and hours without any fatigue... and my brain just keep telling me just one more song when it's already 2am. EL12 spez is tailor made for vocals. Hear Rebecca Pidgeon or Sara K sing and you could fall in love.. with their voice that is. I didn't know what I like in bass until I heard EL12 spez in this amp. This is no subwoofer bass but it's high fidelity bass. It doesn't bleed into the mid but just gives you the impact and you find yourself free falling into sub bass. Tight and controlled. I could ask no more except one more song.  



DecentLevi said:


> Also that's interesting you have Kenwood integrated amp. Not sure if you noticed my posts a while back but I happened to randomly chance upon a model VR-406 from them. It ain't pretty and it's huge and with a fussy digital volume knob, but its' performance makes up for all of that a million-fold! I have been getting astonishing performance from it as a headphone amp that for me completely eclipses ALL other previous incarnations of my audio journey, BAR-NONE. Makes my Quad PA One + headphone amp sound like child's play, which was already leaps better than all other F.A., Garage1217, etc. amps that came before it. Bass and dynamics kick with a force to be reckoned with, huge soundstage, etc. No complaints on the sound. Though it is a 5.1 speaker amp and I'm still interested in tube amps, hence why I'm in the running for an Infinity amp. My Kenwood is from the early 2000's and I guess yours was from the late 80's. Did you compare it as a headphone amp to your others?



Exactly my experience when I tried all my headphones with Sansui au alpha 907mr. I could not believe what I heard. Beyer T1.2 became TOTL again. HD650 became the King of England and LCD-3f because the king of planar magnetics. Sadly I have to sell off the Sansui 907mr to fund the purchase of the equally rare Kenwood KA 3300D. This is Kenwood's masterpiece when they and Accuphase were under one umbrella company. The Kenwood make my tower speakers sings better the Sansui and it's no mean feat because they are both colossal in their performance. I intend to buy the He6se to be driven by the Kenwood with speaker taps.



DecentLevi said:


> What about the Auralic Taurus Mk2, is that your favorite SS headphone amp?



Taurus was a TOTL headphone amp back in 2014 when Darko praised it highly. It is very good but 7 years is a long time in Head-Fi. Dynasties have fallen and new tyrants have risen. Today TOTL solid state headphone amps will cost you your.... I don't know... whatever is most valuable to you.  



DecentLevi said:


> And I heard you're upgrading your Yggy DAC. Will it be the same as the new v2?



Yes but I change my mind. 1st generation Yggy has the details that I crave without vomiting with glare and sibilance. This is where Mike Moffat best r2r dac shows it's magic. I may have a glimpse of what Yggy 2 is like when I bought the Bifrost 2. While the Bifrost 2 is warmer and still very detailed, it just can't compare with Yggy 1. So my motto is 'don't fix whatever is not broken' and I don't go with general recommendations. 

In a few weeks time, a friend is bringing over his Yggy 2 with unison usb and analog 2 and then I will compare it to my Yggy 1. If the Yggy 2 sound better to my ears, I'll eat my hat..... no lost there because I don't wear a hat.   



DecentLevi said:


> PS- I've been deeply engulfed with new career paths recently and still backlogged on catching up with the flury of happenings on the Ultrasonic threads.



Congrats. Career first and head-fi second. Wrong. Wife and family first, career second, golf third and head-fi last. Go back to the Apple earbuds if you have to.

Sorry that's my advice to you but it doesn't apply to me because I'm UntilThen.



DecentLevi said:


> You should be able to also use 6J5 / 6C5 / L63 with two single adapters in the EL11 sockets.
> 
> Interesting, I'm not familiar with KT90, 6550, 807 and KT120. Those should work with my custom Infinity amp also, something @SonicTrance would know.



No just no. Why? My tube supplier knows which tubes sound best and he has many exotic tube amps. Don't ask me what he does for a living. I don't want to know !

I ask him - what do you think of 6J5, 6SL7 and 6SN7. He told me 6SL7 and 6SN7 sound better than 6J5. That doesn't make the 6J5 bad but it just means the other 2 are better. Also I have enough drivers in Odyssey. More combinations than the Rubik's cube. I don't think I need to adapterise my life and my amp more than it should. After all I paid a million bucks for it and it should stay clean and classy. 

Phew I came to the end and I'm 1.5 hours late for dinner !


----------



## UntilThen (Mar 1, 2021)

DecentLevi said:


> Interesting, I'm not familiar with KT90, 6550, 807 and KT120. Those should work with my custom Infinity amp also, something @SonicTrance would know.


I've not heard the 807 yet although I've paid for the Canadian Maple leaf and Radiotron 807. Somehow I must have ordered double the 807 adapters because I got 2 pairs of it. I told my supplier to hold off sending the 807s because I might buy his Tung Sol 6550 1960s next and then he can send it together.

I've not heard the KT90 or KT120 either but I've heard the KT150 recently with a McChanson KT150 SET amp. Pretty good those KT150 surprisingly.


----------



## OctavianH

UntilThen said:


> I've not heard the KT90 or KT120 either but I've heard the KT150 recently with a McChanson KT150 SET amp. Pretty good those KT150 surprisingly.



I have a pair of KT150 and tried them in Elise, the sound for me was like on steroids, plenty of energy and speed. I know that KT120 are in the same direction, I have not heard them but @Scutey has a pair and he tried them with good results. I think he quite likes them.


----------



## UntilThen

Tonight I roll in my NOS GEC KT66 again. I must had only 10 hours with these tubes but they sure sound very good. On par with EL12 spez I'd say. When I have finally gotten all my NOS power tubes, it would be hard to pick which tube to use. I intend to cycle them weekly so I can get used to their tone. 

KT88, KT77, KT66, 6550, EL34, EL12 spez and possibly the 807 are very good. I will even get a pair of KT150. Knowing me, I could not not resist the EL156 because that is a monster tube and being Telefunken, it should be good. In the end, I would have spend a lot of money of NOS tubes but it is what it is. This is the finale and I will do it. Besides who can resist the appeal of rare NOS tubes. I only need a pair of each and if I cycle them weekly, they should last 2 lifetime. 

Brimar 12au7 long plates with GEC KT66.


----------



## Scutey

OctavianH said:


> I have a pair of KT150 and tried them in Elise, the sound for me was like on steroids, plenty of energy and speed. I know that KT120 are in the same direction, I have not heard them but @Scutey has a pair and he tried them with good results. I think he quite likes them.


You are indeed right @OctavianH, the KT120 is a good tube, it leans more towards a new production tube sound, like the KT150, fast, neutral tone, and it's quite a bit cheaper too.


----------



## OctavianH

Scutey said:


> You are indeed right @OctavianH, the KT120 is a good tube, it leans more towards a new production tube sound, like the KT150, fast, neutral tone, and it's quite a bit cheaper too.



I think I will buy a pair when I will also find the KT170. What to say, I like the shape.


----------



## UntilThen

Picture of the 2 different Telefunken EL12 spez. Interestingly one has the word EL12 spezial while the other EL12 spez and one has the words 'made in germany' and the other doesn't. The wording and logo is darker than the other. Also the left pair is bigger than the other.

I find that the bigger tube sounded more penetrating and more piercing and definitely louder than the smaller. To my ears, the bigger tube sound more appealing but both sounded very good.



Even the top side shield is different.


The glass is a darker grey than the other. See both pictures below.


----------



## Scutey

OctavianH said:


> I think I will buy a pair when I will also find the KT170. What to say, I like the shape.


That's an unusual shape, and you've got me interested!


----------



## UntilThen (Mar 1, 2021)

Sadly EL12 spez has been depleted. This is the only new pair I've seen and it's US$499. 

https://www.ebay.co.uk/itm/264977563714

15th Sept 2019, I bought 2 pairs from euroklang for AUD $153 a pair NOS NIB.


----------



## UntilThen

OctavianH said:


> I think I will buy a pair when I will also find the KT170. What to say, I like the shape.


Tomas, can Odyssey use this tube?  This is bigger than a light bulb.


----------



## SonicTrance

UntilThen said:


> Tomas, can Odyssey use this tube?  This is bigger than a light bulb.


I've not seen a datasheet for the KT170 so I can't be sure. But my guess is that it won't be a problem. The only reason it wouldn't work is if it would bias too hot for the OT's and rest of the circuit to handle which is 125mA in your case.


----------



## UntilThen

In layman's terms, is 125mA a lot or just average for most beefy SET amp ?


----------



## SonicTrance

The components are rated for 125mA max. That's a lot. The KT88's will run at about 70mA.


----------



## OctavianH

I looked a little bit to KT63, I think we can use this one as output. I could not find a datasheet with triode connection graphs, but I think is similar with 6F6G, and I found a graph for 6F6 which was biasing almost similar as KT66. Am I right?


----------



## DecentLevi

*This* Spez is only $19,000.00. Theories? Either the seller is a spaz or he thinks it was made by the Tesla car company, LOL.


----------



## OctavianH (Mar 1, 2021)

DecentLevi said:


> *This* Spez is only $19,000.00. Theories? Either the seller is a spaz or he thinks it was made by the Tesla car company, LOL.



I think the seller put the wrong amount. He sells also a pair of EL12 spez. with around 4XX EUR. Anyway, these guys in Italy have much bigger prices than the rest.


----------



## jonathan c

OctavianH said:


> I think the seller put the wrong amount. He sells also a pair of EL12 spez. with around 4XX EUR. Anyway, these guys in Italy have much bigger prices than the rest.


Maybe they are still thinking in terms of Italian lira (ITL) rather than EUR or USD 😜...


----------



## UntilThen

DecentLevi said:


> *This* Spez is only $19,000.00. Theories? Either the seller is a spaz or he thinks it was made by the Tesla car company, LOL.


The seller must think I’m desperate to get another Tesla EL12 spez.


----------



## OctavianH

Well, old russian tubes have interesting logos and markings on them. Yesterday evening I was an artist.


----------



## UntilThen

Are these Fotons and Meze? I'll have to scout around for some nice 6SL7 and 6Sn7s again. They have a more full body tone compared to the leaner sharper 12a*7.


----------



## hpamdr

UntilThen said:


> Are these c Fotons and Meze? I'll have to scout around for some nice 6SL7 and 6Sn7s again. They have a more full body tone compared to the leaner sharper 12a*7.


Yes Foton 6H8C 1955 (6SN7 eq), and Melz  6H12C (6BL7 eq).... 

Meze is in Romania like @OctavianH but build headphone like Empyrean.


----------



## OctavianH (Mar 4, 2021)

Yes, Foton 6H8C and Melz 6H12C.

And for you: RCA 807






And also the pair I like of EL38 (branded Philips, made by Mullard in Blackburn):


----------



## UntilThen

hpamdr said:


> Yes Foton 6H8C 1955 (6SN7 eq), and Melz 6H12C (6BL7 eq)....



Had 6 Fotons 6h8c before but I think I sold them with my GOTL.



OctavianH said:


> And for you: RCA 807



Should be getting my Canadian maple leaf and Radiotron 807 within a week. There's also a white ceramic base 807 from Langrex - not sure I want so many 807 but 807 are supposed to sound good.



OctavianH said:


> And also the pair I like of EL38 (branded Philips, made by Mullard in Blackburn):



Hmmm should I buy myself a pair of EL38.... so many tubes in the pipe line already.


----------



## OctavianH

UntilThen said:


> Hmmm should I buy myself a pair of EL38.... so many tubes in the pipe line already.



2 weeks ago I have stopped any tube acquisition. And I took also other decisions: one would be to stick to octals without top cap. Ok, I will use what I have but I will not order any other exotic ones, and even octals not earlier than after I receive my amplifier and try what I have on it. I expect to be surprised and, maybe, I will not need others. I think Eternity has a lot of potential to use natively enough tubes to fulfil my expectations.


----------



## UntilThen

Absolutely it’s quality you want not quantity.

However I need some fancy light bulbs.


----------



## UntilThen

I am so looking forward to the 596 rectifier because it has 2 top anode caps !


----------



## UntilThen

Hey guys, I'm thinking of getting a tube tester that doesn't cost my apple tree, maybe a lime tree. Any ideas? Firstly I want a working model that won't break down faster than the tubes.

So the tubes I want to test are the usual culprits for Odyssey which you all know what they are by now - both drivers and power tubes.


----------



## OctavianH

UntilThen said:


> Hey guys, I'm thinking of getting a tube tester that doesn't cost my apple tree, maybe a lime tree. Any ideas? Firstly I want a working model that won't break down faster than the tubes.
> 
> So the tubes I want to test are the usual culprits for Odyssey which you all know what they are by now - both drivers and power tubes.



I ordered for myself this one:
https://www.radioelec.com/lampemetre-en-valise-xml-352_387-1507.html
I told the guy that I need a probe with an 100Ohm resistor to measure triode strapped pentodes and he told me he will add one without additional charges.
I have not receive it yet, but I think it is a decent option. Otherwise you can take some classical ones refurbished, I've seen several on Ebay UK.


----------



## UntilThen

And to decorate my music room - yes I have a music room now ! I am thinking of buying these vintage items.


----------



## UntilThen

OctavianH said:


> I ordered for myself this one:
> https://www.radioelec.com/lampemetre-en-valise-xml-352_387-1507.html
> I told the guy that I need a probe with an 100Ohm resistor to measure triode strapped pentodes and he told me he will add one without additional charges.
> I have not receive it yet, but I think it is a decent option. Otherwise you can take some classical ones refurbished, I've seen several on Ebay UK.


But that has no sockets for EL11, EL12 spez tubes ?


----------



## OctavianH

UntilThen said:


> But that has no sockets for EL11, EL12 spez tubes ?



No, but you can use adapters. In my case is fine, my amplifier has only octal tubes.


----------



## OctavianH

Forgot to say, only 6.3V tubes with internally powered, otherwise external power supply OR the bigger version:
https://www.radioelec.com/lampemetre-numerique-dissipation-continue-xml-352_387-2012.html
In my case 6.3V is perfectly fine.


----------



## UntilThen

OctavianH said:


> Forgot to say, only 6.3V tubes with internally powered, otherwise external power supply OR the bigger version:
> https://www.radioelec.com/lampemetre-numerique-dissipation-continue-xml-352_387-2012.html
> In my case 6.3V is perfectly fine.


That's nice but a bit rich.


----------



## OctavianH

UntilThen said:


> That's nice but a bit rich.



Yes, even the small one was not cheap, but it was an investment on my know how. I need to learn stuff and that equipment will be able to help me. On long term, it might worth the penny. We will see.


----------



## UntilThen

Does Eternity look like Infinity?


----------



## OctavianH

My Eternity will be in a smaller chasis, but the same type and vendor as Infinity from the website. The size will be smaller, 330x280xheight (hell knows). I wanted a smaller amplifier, without outputs. There is another Eternity in a standard Oblivion/Citadel chasis, but about this one @hpamdr knows more. So there is no standard chasis, it depends on what you put inside. Mine will have VU-meters on front and mA meters on top.


----------



## UntilThen

Will be interesting to see how all the different versions turn out.


----------



## OctavianH

Absolutely. This is history in the making!


----------



## hpamdr

UntilThen said:


> Does Eternity look like Infinity?


Thomas said that regular Eternity is a bit smaller than Infinity.
Mine will be a bit bigger than normal due to additional heating transformer and some options._ (all custom)_


----------



## hpamdr (Mar 4, 2021)

OctavianH said:


> Otherwise you can take some classical ones refurbished, I've seen several on Ebay UK.


@UntilThen old tube tester are not that great for everyday use, the God/Dad tester are only useful for tube reseller or colection to have an idea of "heath" "exhaust" state. 
The option @OctavianH chose is an easy to go and quite flexible. Even it is not the most advanced tube curve tracer it is a very well done modern tester.
Curve tracer are mostly in kit (uTracer3+ or 6), eTracer  with assembly option, to get a beter idea of what is on the market give a look at  JacMusic tube teste rsection. (most of the missing part from uTracer3 to eTracer have been added in uTracer6)..
I'm also using RoeTest software tube database to have a quick look on tube, socket,...
I will have on loan uTracer3+ at the end of the week....


----------



## UntilThen

Guess I only need to find out how much life left of the tubes and whether they are closely matched.


----------



## UntilThen

hpamdr said:


> Thomas said that regular Eternity is a bit smaller than Infinity.
> Mine will be a bit bigger than normal due to additional heating transformer and some options._ (all custom)_


What tubes are you running?


----------



## hpamdr

UntilThen said:


> What tubes are you running?


I will try to use GU50  or TT22 (do not have yet) on power, small tube in input like E88CC, E188CC, 6N23P-E, single triode 6J5, 6C5,... and VT231,  FDD20 or 12SX7..... and many more...
As OctavianH i will stop lurking on tube until i got the amp at home.


----------



## UntilThen

Good choice. Going 12 volts means cheaper tubes or equivalent quality but there will be less variety. Are any of you using tube rectification?


----------



## OctavianH

No. You are the only one with rectifier.


----------



## UntilThen

OctavianH said:


> No. You are the only one with rectifier.


----------



## OctavianH

I mean tube rectification. Hmm, did I say something wrong? Eternal excuse: english is not my mother tongue. LOL


----------



## UntilThen

OctavianH said:


> I mean tube rectification. Hmm, did I say something wrong? Eternal excuse: english is not my mother tongue. LOL


No I'm just amused that I'm the only one using tube rectification.

I am trying to keep using adapters to a minimum.


----------



## UntilThen

$1000 for a Western Electric 422A.


----------



## hpamdr (Mar 4, 2021)

UntilThen said:


> Good choice. Going 12 volts means cheaper tubes or equivalent quality but there will be less variety. Are any of you using tube rectification?


No rectifier just SS, on previous design I was supposed to use hexfred on a socket and retifier tube if i want. I decided to not go in this direction and use advised SS rectifier only.
I go for 6.3 and 12.6 V driver and power with independent circuit.


----------



## UntilThen (Mar 4, 2021)

Going hexfred is what I did with the Glenn OTL but upon Tomas suggestion, I decided to go with tube rectification to keep with the old school theme. After all I already have a Cossor 53ku, 2 x Mullard GZ32, Mullard GZ34 blackburn factory.

A 596 tube is coming I love ears ! Am going to buy Woo 596 adapter because it's very slick looking in white and silver.

So far the tube amps I've had using tube rectifications are Studio Six and Wa22. They work very well for me.


----------



## UntilThen

Chris, I was using FDD20 in the GOTL. I still have a pair of NOS Tung Sol 12SL7gt bgrp. I'm thinking to ask Tomas to allow the 6SN7 slot for both 6.3 and 12.6 volts via a switch.


----------



## UntilThen

Nah I'm making it complicated again. I need to make it KISS.


----------



## hpamdr

With old school design tube rectification is the good/best choice. I personally prefer not care about rectifier voltage drops and effect on output tubes _(less tube to chase)_.
Most of the new builder also advise SS rectification so t decided to follow Tomas advise.


----------



## SonicTrance

hpamdr said:


> With old school design tube rectification is the good/best choice. I personally prefer not care about rectifier voltage drops and effect on output tubes _(less tube to chase)_.
> Most of the new builder also advise SS rectification so t decided to follow Tomas advise.


There's no point with tube rectifier in Eternity or any of my other amps as they have regulated supplies. Odyssey will be a completely different design where a tube rectifier makes sense.


----------



## UntilThen

There will be tube glow this time on the silver chassis. Lots of glow.


----------



## OctavianH

Friday, beerday. I opened my drawer.


----------



## hpamdr

OctavianH said:


> Friday, beerday. I opened my drawer.


I did not opened my drawer, just my fridge ! (Strong Local beer  )
I received some 6C5 and a pair of Ultron EL34 (Tesla from 69 double O getter) and wait for the last exchange a pair of Tesla EL12Spec....


----------



## UntilThen

It's moving day for me. Lots to do and setup my music room after. Nice drawer there Octavian. I still have a pair of Mullard EL32 smoke glass coke bottle shape.


----------



## OctavianH

hpamdr said:


> I did not opened my drawer, just my fridge ! (Strong Local beer  )
> I received some 6C5 and a pair of Ultron EL34 (Tesla from 69 double O getter) and wait for the last exchange a pair of Tesla EL12Spec....



Nice beer there. I've been drinking lately a lot of Apostel and I quite like it. I always liked the "weissbier".


----------



## hpamdr

OctavianH said:


> Nice beer there. I've been drinking lately a lot of Apostel and I quite like it. I always liked the "weissbier".


Prosit !


----------



## SonicTrance

Slight change in design regarding the protection fuses for excessive plate current. The 10mA fuse I was gonna use for the input stage has a 4.3k resistor inside it. I didn't realize this before and the value is way too large and will mess up the grid bias. I have not seen another 10mA fuse for a reasonable price so we'll skip the fuse for input stage. 
Output stage is not a problem as those fuses are only a few ohms. I've just tested Levi's Infinity using the 125mA fuse. Works like a charm.


----------



## SonicTrance

I will wire the 6J5 sockets so that you can use 6N7 in those natively with the 6N7 triodes run in parallel. Just remember that when looking for bias point for the 6N7 look for 180V @ 2mA, rather than 4mA as the triodes are in parallel the meter will still show 4mA.


----------



## OctavianH

I am wondering if these fuses makes sense only for the output stage where the precision is around 1V for the grid bias. Maybe it makes sense to renounce on them on both stages since for input it was the bigger danger.


----------



## SonicTrance

OctavianH said:


> I am wondering if these fuses makes sense only for the output stage where the precision is around 1V for the grid bias. Maybe it makes sense to renounce on them on both stages since for input it was the bigger danger.


The fuse for the output stage will protect you if you roll tubes and forget to adjust the bias beforehand. As the output stage handles way more current than the input stage it will protect the amp from burnt components in the output stage. The input stage components will (most likely) still be ok if you would forget to adjust. Just watch the meters every time you power on the amp and quickly power off if they read too high current.


----------



## OctavianH

SonicTrance said:


> I will wire the 6J5 sockets so that you can use 6N7 in those natively with the 6N7 triodes run in parallel. Just remember that when looking for bias point for the 6N7 look for 180V @ 2mA, rather than 4mA as the triodes are in parallel the meter will still show 4mA.



Since the 6N7 triodes in a 6J5 socket will operate at a different point than in the 6SN7 socket (via adapter) should we expect a difference soundwise?


----------



## hpamdr (Mar 8, 2021)

I finally got a pair of Tesla EL12spe (1NOS + 1NIB) both from November 1951 "OH", so nice tube !
I also got funny fake tube, it is in fact a 6p3s made in Russia in the end of the 70 with nice "Made in England" printed and named EL39 LOL !!!
I also have in my collection a pair of 6L6GC branded Mazda with exactly same construction --> relabeled 6p3s 
All measure the same. I got the curve tracer and did a first "training" with those tubes.


----------



## OctavianH

These sellers are on Ebay? You should report them.


----------



## hpamdr

OctavianH said:


> These sellers are on Ebay? You should report them.


For fake EL39  yes i explained on picture and got a tube for free because it is fun  For the Mazda, it is in a lot of power tube for instrument amplifier i got many time ago. 
I will mesure some 6C5, 6J5, 6N7 today..


----------



## SonicTrance

OctavianH said:


> Since the 6N7 triodes in a 6J5 socket will operate at a different point than in the 6SN7 socket (via adapter) should we expect a difference soundwise?


It's more linear @ 4mA so, theoretically, it should sound a bit cleaner in the 6SN7 socket than the 6J5 sockets.


----------



## hpamdr (Mar 9, 2021)

SonicTrance said:


> It's more linear @ 4mA so, theoretically, it should sound a bit cleaner in the 6SN7 socket than the 6J5 sockets.


I have made some measure with 2 6n7gt  one Visseaux (VS) and one Haltron (HT) grey glass (stronger tube).
The std measurement is in the range of the datasheet (just to check the tracer is well calibrated).
I've measured single triode for 4ma at 180V grid voltage  bias will be (-2 or -2.5).   (T1-T2 curve)
I've also strapped both triode in parallel and then measured for 4ma at 180V grid voltage  bias will be (-3.45 or -3.7). (T1+T2 curves) This is almost the same as measure at 2ma for single triode. We can see that even at 2ma the curve is already in the linear part.


----------



## hpamdr (Mar 9, 2021)

And for the fun, some measurement for EL84, EL12N, 1540 special 6p3s-e and 6p6s (6V6 Russian equivalent)..
_All measurement are done strapping pentode as triode g3+k if needed, A+g2 using 100R resistor._


----------



## OctavianH

hpamdr said:


> I have made some measure with 2 6n7gt  one Visseaux (VS) and one Haltron (HT) grey glass (stronger tube).
> The std measurement is in the range of the datasheet (just to check the tracer is well calibrated).
> I've measured single triode for 4ma at 180V grid voltage  bias will be (-2 or -2.5).   (T1-T2 curve)
> I've also strapped both triode in parallel and then measured for 4ma at 180V grid voltage  bias will be (-3.45 or -3.7). (T1+T2 curves) This is almost the same as measure at 2ma for single triode. We can see that even at 2ma the curve is already in the linear part.



So if I understood correctly your graphs and measurements, 2 tubes of different vendors, of the same type, might require different grid bias voltages up to 0.5V based on their health and other parameters. So this means that we cannot rely on a single measurement for, let's say, 6SN7 and consider any 6SN7 to bias the same. I'll take a look again at those graphs just to be sure I understood it right. Anyway, very interesting, thanks for sharing.


----------



## hpamdr

OctavianH said:


> So if I understood correctly your graphs and measurements, 2 tubes of different vendors, of the same type, might require different grid bias voltages up to 0.5V based on their health and other parameters. So this means that we cannot rely on a single measurement for, let's say, 6SN7 and consider any 6SN7 to bias the same. I'll take a look again at those graphs just to be sure I understood it right. Anyway, very interesting, thanks for sharing.


Yes, it seems that you are right. But in this case the halton is really strong.. If you have multiple tubes same type, matching them is trying to find pair that measures the same/bias as same value. This is a bit extreme, but with measuring tool that is much easier


----------



## OctavianH (Mar 9, 2021)

hpamdr said:


> Yes, it seems that you are right. But in this case the halton is really strong.. If you have multiple tubes same type, matching them is trying to find pair that measures the same/bias as same value. This is a bit extreme, but with measuring tool that is much easier



Yep, I was thinking about the fact that it would not be easy to use the Tube Rolling Add-on without a measurement device and also that matched pairs are more important than I thought. I have to admit, at first sight I thought we can just make a general table for each tube type and then just adjust. Having only one meter/stage might be that we will need to measure both tubes used in the stage, find the closest one and put the grid bias (a+b)/2 to be sure we are "in the middle" for both.

PS. Very interesting also your results related to single/double triode bias. So basically it does not matter if you use 2 x 6N7 in the 6J5 slots or one via adapter in the 6SN7. Cool.


----------



## hpamdr

OctavianH said:


> Yep, I was thinking about the fact that it would not be easy to use the Tube Rolling Add-on without a measurement device and also that matched pairs are more important than I thought. I have to admit, at first sight I thought we can just make a general table for each tube type and then just adjust. Having only one meter/stage might be that we will need to measure both tubes used in the stage, find the closest one and put the grid bias (a+b)/2 to be sure we are "in the middle" for both.
> 
> PS. Very interesting also your results related to single/double triode bias. So basically it does not matter if you use 2 x 6N7 in the 6J5 slots or one via adapter in the 6SN7. Cool.


This is not mandatory as we can run with not so bad/good value from datasheet or measures for same type. To what I've understood, it is possible to fine tune once the amplifier is running. But to be precise, the tube have to be hot to get right value. 
Hot 🔥 mean, heated more than two minutes. At startup tube mesure much less and is not linear. So you have to wait before measuring or fine tune.


----------



## OctavianH

But does it matter if you play music during fine tuning or not? I mean does it influences the tube parameters?


----------



## SonicTrance

OctavianH said:


> Yep, I was thinking about the fact that it would not be easy to use the Tube Rolling Add-on without a measurement device and also that matched pairs are more important than I thought. I have to admit, at first sight I thought we can just make a general table for each tube type and then just adjust. Having only one meter/stage might be that we will need to measure both tubes used in the stage, find the closest one and put the grid bias (a+b)/2 to be sure we are "in the middle" for both.


You don't need a tube tester or curve tracer to use the tube rolling add-on. A table for each tube type is more than enough. Remember that in the stock version, without rolling add-on, the bias is fixed at all times. There's always going to be differences from tube to tube. No way around that.


----------



## SonicTrance

hpamdr said:


> This is not mandatory as we can run with not so bad/good value from datasheet or measures for same type. To what I've understood, it is possible to fine tune once the amplifier is running. But to be precise, the tube have to be hot to get right value.
> Hot 🔥 mean, heated more than two minutes. At startup tube mesure much less and is not linear. So you have to wait before measuring or fine tune.


Yes, you can fine tune once the amp is running and tubes are hot. I don't recommend playing music while you do this. Mainly because of concentration issues


----------



## SonicTrance

@hpamdr 
You did have EL12 spez, correct? I'd love to see the triode curves for it! Also, great work so far!


----------



## hpamdr (Mar 9, 2021)

SonicTrance said:


> @hpamdr
> You did have EL12 spez, correct? I'd love to see the triode curves for it! Also, great work so far!


I have a brand new pair of Tesla, I did not built adapter for it yet. I will measure EL12sp and EL39 once i get an anode cap wire for uTracer. (I should have the part to build it  )
Do you want full curves multiple Va/Vg or just at Va at 200V full ranges and "zoom" around 15ma to 45ma.
EL12Sp is Tesla version of Telefunken EL12Spez (s_ame specification but much nicer in black and silver suit_) 
(picture with same date code as me OH : November 1951)


----------



## SonicTrance

hpamdr said:


> Do you want full curves multiple Va/Vg or just at Va at 200V full ranges and "zoom" around 15ma to 45ma.


The grid curves in relation to Ia and Va is what I'm most interested in. From that we can read linearity and operating points. The zoom graphs are also good for more accurate readings of certain bias points of course.


----------



## OctavianH

I hope today or tomorrow latest I'll be able to join the Tube Scientific Measuring & Research Team.


----------



## hpamdr

SonicTrance said:


> The grid curves in relation to Ia and Va is what I'm most interested in. From that we can read linearity and operating points. The zoom graphs are also good for more accurate readings of certain bias points of course.


@ sonicTrans I have made some measurement on EL11, EL12sp , EL12N and EL39 see if the measure fit your need.


----------



## SonicTrance

@hpamdr 
This is great! Thanks slot! 
Levi's Infinity is almost done so next Im going to test all the tubes he sent me in the amp. I'll update here with the bias points.


----------



## OctavianH

SonicTrance said:


> Levi's Infinity is almost done so next Im going to test all the tubes he sent me in the amp. I'll update here with the bias points.



We don't mind some pictures, of course if the owner allows it.


----------



## SonicTrance

OctavianH said:


> We don't mind some pictures, of course if the owner allows it.


Of course! I'll take some pics once complete!


----------



## hpamdr

SonicTrance said:


> @hpamdr
> This is great! Thanks slot!
> Levi's Infinity is almost done so next Im going to test all the tubes he sent me in the amp. I'll update here with the bias points.


Just for information, if you see compliance error that mean that uTracer stop measure after reaching b200ma in this case(this protect tube and tracer board). Max Va 400V on this tracer3. Utracer6 go above those limitations.


----------



## OctavianH (Mar 11, 2021)

History in the making, guys!





Ok, and some testing to understand how this device works.

1) 6H8C health test, according to the table (equivalent to 6SN7GT):





Connection:





Triode 1:





And triode 2:





Hmmm, 14.5mA vs 19mA at the same testing conditions? WOW. Am I doing something wrong?

Then a 6V6 strapped to triode test:





Connection as here:





And result was strange:





At Plate Voltage = 200V and G1 = -13.4 (close to what a graphs shows for 20mA) I got 0.2mA. Then reducing the grid bias I was able to obtain at almost 0V 0.5mA. Quite far away from 20mA I expect to have in the output stage. So obviously I have made something wrong, or my tubes are almost dead. Do not worry guys, these were tubes for learning, the important ones will be measured when I'll understand my mistake.

@hpamdr do you see something wrong here?

PS. I measured again the same 6V6 according to the manual:





Connection:





And measurement showed 68mA when expected was 80mA.


----------



## hpamdr

OctavianH said:


> History in the making, guys!


Now it is time to play, and discover that it will be very rare to find two tubes which measure the same at multiple points ! 
(Even if seller claim about matched pair this is generally valuable at one point only)


----------



## hpamdr

OctavianH said:


> Then a 6V6 strapped to triode test:
> 
> 
> 
> ...


Hi connection seems to be OK.  (start using regular connection on the manual with g2 measure, and then remove g2 wire only and strape with the 100R wire from g2 pin to A cable ) I encourage you to always use some wire color as the one on the measuring plug like you did. 

68ma for 80ma is not so bad.
0.2ma is a very low value this can arise if the tube is not heated enough or exhausted...If you do not strap correctly g2 you can have such issue, verify with a DMM that the 100R wire is really 100R and conductive.

// during my test i also found an EL11 with such measure it is one which i called very bad on the amp.


----------



## OctavianH

hpamdr said:


> Hi connection seems to be OK.  (start using regular connection on the manual with g2 measure, and then remove g2 wire only and strape with the 100R wire from g2 pin to A cable ) I encourage you to always use some wire color as the one on the measuring plug like you did.
> 
> 68ma for 80ma is not so bad.
> 0.2ma is a very low value this can arise if the tube is not heated enough or exhausted...If you do not strap correctly g2 you can have such issue, verify with a DMM that the 100R wire is really 100R and conductive.
> ...



I will do it. Thanks for helping me. I already measured the resistor and it is fine, around 99.x Ohm (so 100R is fine). I'll investigate further. Something is "fishy".


----------



## OctavianH (Mar 11, 2021)

hpamdr said:


> Hi connection seems to be OK.  (start using regular connection on the manual with g2 measure, and then remove g2 wire only and strape with the 100R wire from g2 pin to A cable ) I encourage you to always use some wire color as the one on the measuring plug like you did.



Ok, I tried again, like this:





The only difference here is that I removed G2 and put the pin 4 to Plate (not to 3 which was connected via plate) and have not linked G3 + K on pin 8. G3 remained on pin 1 as in the manual. Maybe an issure related to imbricated cords and maybe they do not make proper contact? Brrr.

And the results were MUCH BETTER (as expected):





Now, I measured the cord with the 100R and it is fine, it is not clear to me what you mean by "conductive"?


----------



## hpamdr

OctavianH said:


> Ok, I tried again, like this:
> 
> 
> 
> ...


This should the same, connecting pin 4 / 3 using 100R cable, on 6v6 you do not have any pin for G3 sor you do not need the cable at all. 
The only thing that you have to be careful is to first plug measuring wire A,G1,K F,F+ and then G3 if it make sense to corresponding pin numbers and finally wire G2 pin to anode pin or measuring point.


----------



## OctavianH

hpamdr said:


> This should the same, connecting pin 4 / 3 using 100R cable, on 6v6 you do not have any pin for G3 sor you do not need the cable at all.
> The only thing that you have to be careful is to first plug measuring wire A,G1,K F,F+ and then G3 if it make sense to corresponding pin numbers and finally wire G2 pin to anode pin or measuring point.



Yep, in the end I've done like this:






This is the connection which makes sense for me. Then I measured one 6H8C (triode1 + triode2), a pair of Sylvania 6V6 and a pair of GEC KT66.
First step was to measure at which grid bias value we will have the ideal operating point (180V/4mA or 200V/20mA). I obtained different values for each triode.
Then, I calculated the average value and played a little bit +0.1V and -0.1V near that value. What I obtained is interesting:



 

So, the triodes inside the 6H8C measure quite differently. The best grid bias was for me -7.1V but one of them was below 0.7mA and the other was over 0.9mA.
For outputs, Sylvanias were the same measuring differently. I found that the best grid would be -13.1V but there both were below/over 1.5mA from the ideal value.
For GEC KT66, which are better matched electrically, -21V provided me quite closer values. I think the GEC KT66 is the winner here.

Now, if for output the deviations are under 10%, for input we have quite 20%. So, I am not sure if a common grid biasing for both triodes in the input section is fine. OK, for double triodes you cannot do other stuff than searching for a better matched tube, but for the 6J5 slots you are able to match them better if you have a different trimmer for each one. 

Next step for me would be to measure a pair of GEC L63 and see how close they are.

Now, I hope I understand things right. What I try to do here, the purpose of my measurements, is to see how I can choose optimal common grid bias value for input and output stage for not very "lucky" pairs of triodes. And see how things are going.


----------



## hpamdr

OctavianH said:


> Yep, in the end I've done like this:
> 
> 
> 
> ...


You have now an idea about unmatched triode. This is not a big deal and at least less perceptible in amplifier than the number states...
@SonicTrance
10% for pairing is more than enough to me. 20% should be still acceptable. The trick will be to match in our safety range 180V-4ma , 200V - 20ma or 40ma..

As you said pairing 6J5 6c5 L63 .... will be easier if you have enough tubes. Pairing inside 6SN7, Ecc32, 6H8C, ... will be a bit more difficult  In F.A. as both triode are strapped you fall back  to pair single triode like for 6J5. This will also be the case if you strap 6n7 to 6j5 in eternity.

I have some dual triode 6N7GT, 6SN7, 7N7, VT231, ECC88 ... well balanced but this is not the majority of my tubes. Most of my 6H8C are also unmatched like yours. I measured with my old tube tester and now if i have time, i will measure with the utracer.


----------



## OctavianH

Ok, last post on this, I think I intoxicated anyone with my measurements. I measured an "electrically matched pair" of GEC L63 bought at a little bit higher price from UK and "Voila":





This looks much better than the 6H8C: at -6.8V grid bias we have max 0.2mA from the optimal point which is around 5%.

My conclusions:
1. We need quite decently paired tubes for input stage, and sometimes it makes sense to have electrically matched pairs.
2. We need to find out, for input and output stages which is the tolerance and measure to see what we can use and what not because it does not measure in the limits we accept. => here you said 10-20% would be nice and will not be audible.

I expect that this pair of GEC L63 with the pair of GEC KT66 will be a killer combo.

Now, looking in the tube calculator it was advising for KT66 = -19.65V. Well, from what I measure I see my value is -21V.


----------



## SonicTrance

OctavianH said:


> So, the triodes inside the 6H8C measure quite differently.


That's a very unbalanced tube! I guess it has been used and only one triode connected. Those values will still work fine in the amp but some channel imbalance could perhaps start to be heard with such an unbalanced tube.  



OctavianH said:


> We need to find out, for input and output stages which is the tolerance and measure to see what we can use and what not because it does not measure in the limits we accept.


Input stage a little under 3mA to 5mA is ok. Output stage 15mA - 24mA is ok (fuse will blow @ 25mA)


----------



## OctavianH

SonicTrance said:


> That's a very unbalanced tube! I guess it has been used and only one triode connected. Those values will still work fine in the amp but some channel imbalance could perhaps start to be heard with such an unbalanced tube.



This tube is the perfect candidate for "lightning". I'll measure the other 2 I have to decide which is the winner for music listening.

By the way, the mA meter will be linked to one triode? So we will basically see the exact current in one channel and if the tubes are properly matched assume the other one is close to this one we can observe? Or you think about a more complex way to measure average of both currents or?


----------



## SonicTrance

OctavianH said:


> By the way, the mA meter will be linked to one triode? So we will basically see the exact current in one channel and if the tubes are properly matched assume the other one is close to this one we can observe? Or you think about a more complex way to measure average of both currents or?


@hpamdr amp will have switches to switch between the channels to be able to read the currents on all tubes. I was going to ask if you wanted this as well. I'll send you a pm.


----------



## UntilThen

The next 'big' item for Odyssey has arrived.  

Made of pure ivory and ceramic from the African safari.


----------



## UntilThen

SonicTrance said:


> @hpamdr
> This is great! Thanks slot!
> Levi's Infinity is almost done so next Im going to test all the tubes he sent me in the amp. I'll update here with the bias points.


I'm holding my breath waiting to hear what you think of EL11 and EL12 spez. Warren Buffet's fortune depends on your findings !


----------



## hpamdr

UntilThen said:


> I'm holding my breath waiting to hear what you think of EL11 and EL12 spez. Warren Buffet's fortune depends on your findings !


At least if EL11 are not all perfect, this a 6SN7GT (VT231 Sylvania) very well matched and spotting datasheet bias. Bias at -6.9V for 4ma at 180V.
Ia with square is T1, Is with dotted line is T2 both measured at same time.


----------



## UntilThen

hpamdr said:


> At least if EL11 are not all perfect



Are you saying all EL11s are not perfect or just your particular EL11.

In any case I'm not concern about graph readings. I know how EL11 sound in the GOTL and as have many others. It's a great tone.


----------



## hpamdr

UntilThen said:


> Are you saying all EL11s are not perfect or just your particular EL11.
> 
> In any case I'm not concern about graph readings. I know how EL11 sound in the GOTL and as have many others. It's a great tone.


I should have been more precise, i have measured some EL11 to mach as pair in input, and found it a bit difficult as i got a lot of "used" tubes. None is measuring the same.
What i can say is that the one i disliked in the amp are the one with bad curves.
I have also one EL11 which was humming a lot in F.A, and when measuring i found that the tube was "used" what i was knowing but also almost exhausted...
On F.A EL11 with EL39 is also a vey good combo...


----------



## UntilThen

Now I understand you. 😊 You should hear my matched pairs of EL11. 😊


----------



## hpamdr

I'm not as fortunate as you... I only have one pair well matched but not the strongest 
Even the single pair of EL12Sp I own is not matched


----------



## OctavianH

hpamdr said:


> I'm not as fortunate as you... I only have one pair well matched but not the strongest
> Even the single pair of EL12Sp I own is not matched



Which raises the question: What is more important, electrically matchig or strong/weak measurements?
I have the same dilemma with my 4 x Tronix 6V6G, to are stronger and 2 are almost perfectly matched (Vgrid for 200V 20mA are -14.3, -10.5, -12.3, -10.6).
I can choose the "stronger" ones with bigger bias values but not so good matched, or the "weaker" which are very close.


----------



## SonicTrance

OctavianH said:


> Which raises the question: What is more important, electrically matchig or strong/weak measurements?
> I have the same dilemma with my 4 x Tronix 6V6G, to are stronger and 2 are almost perfectly matched (Vgrid for 200V 20mA are -14.3, -10.5, -12.3, -10.6).
> I can choose the "stronger" ones with bigger bias values but not so good matched, or the "weaker" which are very close.


Matched is better! Use the 14.3 and 12.3 together and of course the matched ones at 10.5 and 10.6. It's going to be interesting to see how accurate those measurements are ones you receive your amp


----------



## OctavianH

SonicTrance said:


> Matched is better! Use the 14.3 and 12.3 together and of course the matched ones at 10.5 and 10.6. It's going to be interesting to see how accurate those measurements are ones you receive your amp



Well, my dilemma was roughly ended because one of the weaker tubes died. So now I have 3. Anyway, I measured the Filament voltage of the tester and seems fine.
If I want to measure in socket the Plate voltage, it is clear to me which one is the Plate (pin 3) but where I can take a ground?


----------



## SonicTrance

OctavianH said:


> If I want to measure in socket the Plate voltage, it is clear to me which one is the Plate (pin 3) but where I can take a ground?


On a 6V6 you should measure plate voltage from pin  3 to pin 8. You always measure tube voltages in relation to the cathode. Grid voltage is grid -> cathode and anode voltage is anode -> cathode. In Infinity and Eternity the cathode is at ground so we don't have to measure at the cathode, just ground.


----------



## SonicTrance

Testing in progress


----------



## OctavianH (Mar 13, 2021)

SonicTrance said:


> On a 6V6 you should measure plate voltage from pin  3 to pin 8. You always measure tube voltages in relation to the cathode. Grid voltage is grid -> cathode and anode voltage is anode -> cathode. In Infinity and Eternity the cathode is at ground so we don't have to measure at the cathode, just ground.



I was thinking the same, I am glad that you confirmed it. I will soon post my measurements because these are raising some questions and might be useful for all of us to look at them and discuss 2-3 cases.



SonicTrance said:


> Testing in progress



Wow, this looks impressive. Silver front is a surprise for me. But it looks really nice, a pair of Mullard 6J5 + a pair of Philips EL3N. Cool!
A picture of from the top view would be useful to understand better the proportions and layout. The 6SN7 slot is in front in the center rotated 90 degrees due to lack of space?


----------



## SonicTrance

OctavianH said:


> Wow, this looks impressive. Silver front is a surprise for me. But it looks really nice, a pair of Mullard 6J5 + a pair of Philips EL3N. Cool!
> A picture of from the top view would be useful to understand better the proportions and layout. The 6SN7 slot is in front in the center rotated 90 degrees due to lack of space?


Thanks!
More, proper, pics will come later after testing is done. This was just a quicky.

I rotated the 6SN7 socket as I thought it looked better, less cramped. All sockets are rotated the same way though. Only the fastening is different on the 6SN7 socket.


----------



## hpamdr

SonicTrance said:


> Testing in progress


Nice lab and nice infinity... Do you have small bias meter on top and bigger vue meter on front ? (or is is just a perspective distortion)


----------



## hpamdr

OctavianH said:


> Which raises the question: What is more important, electrically matchig or strong/weak measurements?
> I have the same dilemma with my 4 x Tronix 6V6G, to are stronger and 2 are almost perfectly matched (Vgrid for 200V 20mA are -14.3, -10.5, -12.3, -10.6).
> I can choose the "stronger" ones with bigger bias values but not so good matched, or the "weaker" which are very close.


I remember in old ages of ecc88 and el84 amplifier, the tube amp specialist (of the shop i was always visiting) was doing cross matching.. 
Let say you have a dual triode tube with not matched section, he was in purpose using a stronger output tube in the lesser driver section trying to compensate a bit..

@SonicTrance
I do not know if with Tomas design (excluding Odyssey) this is still adequate ? For Odissey as it is old school design, I would expect same behavior as old amp.


----------



## OctavianH (Mar 13, 2021)

Ok guys, it seems Friday Beerday transformed in Weekend Measuring, Matching and Beer drinking.





We have a victim, a brave 6V6G who died on the Altar of Science. But we have also some measurements:

I measured output stage for plate 200V / current 20mA. There are 2 results because I try to match my pairs and decide which are properly matched or not.
On input stage I measured for plate 180V / 4mA single triodes as a pair (similar to outputs) and double triodes as T2 and T1 (pin 2 and pin 5 anode).
The values in red are the medium bias which puts both triodes as close as the ideal value as possible. The markings column is not relevant for anyone except me, are some distinctive signs for me to identify the tube in the pair, so ignore it.









And here, we have some intersting results. For example GEC L63 (brown base, straight clear glass) measures bias around -6.7V. But when I measured GEC CV1067 (grey glass, ST shape, older L63) I've seen that the bias goes to -6V. This is problematic because if we want to use a common bias for 6J5, we might go out of range with one of the types. I was not aware that such differences are happening in the same type.  For example, the CV1067 at the bias of L63 goes around 2.4mA. Not quite in the tolerance of the input stage:





Another interesting part is related to KT66. The MOV KT66 grey glass (WW2) biases around -18V while 2 pairs of GEC KT66 brown base clear glass go up to around -21V. Deja vu? Similar with the GEC 6J5 grey glass vis  the clear glass? Here the same point mentioned before, but since it is output stage and we have a much better tolerance I have not measured one at the bias of other.

Now maybe I measured wrong, or the tubes are not burned in since I've never used them, but the question is, in input stage, if we have such difference between 6J5 and equivalents, what we can do. In my case, I have a special request for Eternity, a switch to use fixed bias vs variable bias, fixed bias being 6J5 / KT66. This switch which I call during week time "Tube rolling off" and during weekend "Beer rolling on" might be problematic if  I roll these 2 types of tubes. I am curious if anyone measured at 180V / 4mA any 6J5 and had similar results.

And now, regarding EL32 and EL38, I measured 2 pairs, Mullard EL32 grey glass ST shape and Mullard (rebranded Philips) EL38 black base clear glass:





My results are these ones, but if someone might measure these and share results I would be grateful.

In conclusion, what I marked *green* are the "electrically matched pairs" at the operation points of Eternity, the prio 1 tubes I will try in the amplifier. What I marked *yellow* is a decent tube and I will leave to the end the *orange*. The *red* will not be used at all. The EL38 will be used since I want to try it, even if the matching is not as good as expected. I made several close measurements to be sure I am on the right path. Now I'll just wait to see what others measure or find and compare with my results. I have somewhere 2 additional Sylvania 6V6G and I might obtain better matching results if I will remember where are those.


----------



## SonicTrance

hpamdr said:


> I remember in old ages of ecc88 and el84 amplifier, the tube amp specialist (of the shop i was always visiting) was doing cross matching..
> Let say you have a dual triode tube with not matched section, he was in purpose using a stronger output tube in the lesser driver section trying to compensate a bit..
> 
> @SonicTrance
> I do not know if with Tomas design (excluding Odyssey) this is still adequate ? For Odissey as it is old school design, I would expect same behavior as old amp.


I'd not recommend compensating a week input tube with a strong output tube. The circuit is most happy with good strong tubes and that goes for all amps. But, especially Infinity and Eternity.

@OctavianH 
It's good to see you start measuring! It's fun huh?  



OctavianH said:


> I have a special request for Eternity, a switch to use fixed bias vs variable bias, fixed bias being 6J5 / KT66. This switch which I call during week time "Tube rolling off" and during weekend "Beer rolling on" might be problematic if I roll these 2 types of tubes. I am curious if anyone measured at 180V / 4mA any 6J5 and had similar results.


Don't worry about tube differences. There's a whole lot of tolerance to these kinds of circuits. 

Here're my bias measurements for Infinity:

Output tubes Infinity 200Va, 40mA Ia
KT66/7581A: -17.3
EL39: -10.0
EL38: -9.0
EL12sp Tesla: -7.8
EL12 spez Telefunken: -6.7
EL3N: -3.9 @ 35mA 
EL32: -11.7 @ 35mA
EL12: -6.2

Input tubes Infinity @ 180Va, 4mA Ia
6J5/6C5/6SN7: -6.30
EL11: -7.80
6N7 in 6J5 sockets: -3.65
6N7 in 6SN7 socket: -2.35
E88CC: -4.90
E80CC: -3.80
12AV7: -4.50
6CG7: -6.20
MHLD6: -7.55
6SL7: -765mV @ 3mA

I chose to run EL3N and EL32 @ 35mA to put a little less stress on them. Same thing with the 6SL7 @ 3mA.


----------



## OctavianH (Mar 13, 2021)

SonicTrance said:


> Here're my bias measurements for Infinity:
> 
> Output tubes Infinity 200Va, 40mA Ia
> KT66/7581A: -17.3
> ...



Many thanks on that! I'll measure for fun EL32 on 35mA and EL38 on 40mA just to compare with your results.  For me, in Eternity, output stage will run around 20mA so I guess my measurements are close to what will be. At least I expect so. I am really curious what bias you will find for 6J5 and KT66 on Eternity. My results are problematic, as mentioned above.

I observed that several pairs are "slow starters". This means you need around 4-5 minutes to obtain coherent measure results. For example GE 6550A (KT88 replacement, expected to bias close to KT88 around -24V) provided confusing results, I made a separate note to take again a look. Same was for Genalex KT77 which honestly measured out of range. And even if you might think these are coherent, I have a feeling something is not right there. I will investigate further.

Regarding tolerance, I try to remain in the 3-5mA and 15-24mA as you mentioned.

And yep, measuring is fun. I think beer drinking, sex, tube measuring are on top but if the pandemic goes off, a Black Sabbath concert might change the order. LOL


----------



## SonicTrance

OctavianH said:


> I am really curious what bias you will find for 6J5 and KT66 on Eternity.


The 6J5's will be the same as in Levi's Infinity if I use the same tubes. KT66 is another story of course.



OctavianH said:


> Regarding tolerance, I try to remain in the 3-5mA and 15-24mA as you mentioned.


Yep, that's good.



OctavianH said:


> And yep, measuring is fun. I think beer drinking, sex, tube measuring are on top but if the pandemic goes off, a Black Sabbath concert might change the order. LOL


Haha, yes I agree!


----------



## OctavianH

SonicTrance said:


> The 6J5's will be the same as in Levi's Infinity if I use the same tubes. KT66 is another story of course.



According to my measurements -6.3V will make my 6J5 jump over 5mA. But most probably you measured directly on the amp and other factors were involved.


----------



## SonicTrance (Mar 13, 2021)

I posted pics here: https://www.head-fi.org/threads/oblivion-ultrasonic-studios.902926/post-16236147

Here's a pic from the top


----------



## OctavianH

SonicTrance said:


> I posted pics here: https://www.head-fi.org/threads/oblivion-ultrasonic-studios.902926/post-16236147
> 
> Here's a pic from the top



It is an incredible beauty. I love it!


----------



## hpamdr (Mar 13, 2021)

OctavianH said:


> Ok guys, it seems Friday Beerday transformed in Weekend Measuring, Matching and Beer drinking.
> 
> 
> 
> ...


You did a wonderful job here 
What to do with your KT77, heat the tube and wait long, 10 minutes with the one that measure weak and retest....... until measure is stable. (Also verify limits on heater circuit 1.4A is already a bunch )  I use an external heater on my uTracer.

If it is not better,  try to get another Kt77 but keep it in case you get another KT77 with same measure you will have to bias like a 6v6 !

Measuring is very cool and gives you an idea of what have been purchased.


----------



## OctavianH

hpamdr said:


> If it is not better,  try to get another Kt77 but keep it in case you get another KT77 with same measure you will have to bias like a 6v6 !



Well, these are original Genalex KT77, very rare and expensive. I will just use them on Elise, they are too expensive to make sense of searching for another one. I will think about these results and see if I made something wrong. If those KT77 need 10 minutes to get to proper currents it means I need to wait 10 minutes on the amplifier to use them. Thanks, but no thanks.

And yes, measuring helps you understand much more about tubes, amplifiers and how to use them, at least for me.


----------



## UntilThen

SonicTrance said:


> I posted pics here: https://www.head-fi.org/threads/oblivion-ultrasonic-studios.902926/post-16236147
> 
> Here's a pic from the top


Well done ! Turn out very well. There are enough tube combinations here to keep Levi very busy.


----------



## SonicTrance

UntilThen said:


> Well done ! Turn out very well. There are enough tube combinations here to keep Levi very busy.


Yep, there're endless possible combinations. Just have to look for operating points on the tube datasheets.


----------



## OctavianH (Mar 14, 2021)

Sunday, 6J5 day. I measured my tubes at -6.3V which is the grid @SonicTrance decided to use in his measurements.






And the currents:





So the L63 brown base clear glass will go towards 5mA, one of them reaching it. The grey glass will remain towards 3mA.
Seems a medium value, now if this is fine or not, as he said, we have a range of playground. However, I would be curios if any channel inbalance would be heard.

Which is the 6SN7 bias? -6.8V?

Later edit: 6SN7 bias is the same, -6.3V. LOL I need more coffee.


----------



## hpamdr (Mar 14, 2021)

OctavianH said:


> Sunday, 6J5 day. I measured my tubes at -6.3V which is the grid @SonicTrance decided to use in his measurements.
> 
> 
> 
> ...


I measured 8 Viseaux 6J5MG i'm lucky enough to have bias at 6.2, 6.2 , 6.4, 6.5 ,6.55, 6.6, 6.6,  7.2 so  3 pairs with almost perfect match, one in the middle of two pair and one above the other very strong.... I still have to measure KR and RCA 6J5...

I've also measured 6SJ7 tubes on 5 tubes i have one completely dead  and two pairs with 0.2V of mismatch for 3ma.

I also measured 10 GU50 where bias goes from -21V to -33.6V ??? I still have to measure some more but was able to find 3 good pairs...

--edit
Bias for my VT231 is 6.9V on datasheet it seems to be around -7V, so 6.8V is a good value !


----------



## OctavianH

I wonder how many GU50 you have since you measured 10. LOL

I like you, you are like me, do not buy a pair of tubes, but a box!


----------



## hpamdr

OctavianH said:


> I wonder how many GU50 you have since you measured 10. LOL
> 
> I like you, you are like me, do not buy a pair of tubes, but a box!


I have 20 GU50 in 3 lot some new and some a bit used..
I had a lot of surprise in the past with 6H8C and other dual triode when using my CTH amplifier so prefer to get more match if i can and resell.
This is also why for expensive tube (over 50$) i prefer to buy from a corporate seller with matching service even paying more than getting unmatched tube.


----------



## OctavianH

Trying to match better my pair of L63 I measured all 6 I have and it seems 5 of them are 5-5.2mA @ -6.3V and only one is 4.7mA. So in the end I decided to use 2 x 5.0mA.
We will see if this current will create problems or not in the input stage.


----------



## hpamdr

If all L63 goes at 5mA for same -6.3V bias, why not biasing for 4mA let say -6.7V ?
For me, this should be safer than reaching 5V at startup.


----------



## OctavianH

hpamdr said:


> If all L63 goes at 5mA for same -6.3V bias, why not biasing for 4mA let say -6.7V ?
> For me, this should be safer than reaching 5V at startup.



I have a specific feature of fixed bias with a switch. For that fixed bias I asked Tomas to set the bias default for KT66 / 6J5 or 6SN7. For these tubes I guess I'll use the variable bias and put it around -6.5V or as you say -6.7V. I will use the ST shaped ones with the fixed settings.


----------



## hpamdr

OctavianH said:


> I have a specific feature of fixed bias with a switch. For that fixed bias I asked Tomas to set the bias default for KT66 / 6J5 or 6SN7. For these tubes I guess I'll use the variable bias and put it around -6.5V or as you say -6.7V. I will use the ST shaped ones with the fixed settings.


Probably you could ask Tomas to let you chose bias resistors to have something more in the middle of the tube you want to use.. I do not know if Tomas will use small trimpot (regulation with screwdriver) or fixed resistor. As you discovered, fixed bias will not match a lot of tubes so the predefined bias value should be chosen to really match multiple set and be careful to not use it with tubes over limits...


----------



## OctavianH

hpamdr said:


> Probably you could ask Tomas to let you chose bias resistors to have something more in the middle of the tube you want to use.. I do not know if Tomas will use small trimpot (regulation with screwdriver) or fixed resistor. As you discovered, fixed bias will not match a lot of tubes so the predefined bias value should be chosen to really match multiple set and be careful to not use it with tubes over limits...



If we raised to -6.5V the ST shaped fall below 3mA (one of them). So -6.3V is fine, because it matched also some 6SN7 tubes I want to use. I'll use these strong ones with variable bias, with aging I expect the value will decrease.


----------



## UntilThen

807 have arrived and they are giant tubes. Much bigger than EL12 spez. Probably about EL39 size.

Radiotron 807 - Made in Australia


Sylvania 807 maple leaf - Made in Canada ... I think


Radiotron 807 even came with tube data sheet.


The box size of the Radiotron outsize the Sylvania box. These are brand new and original boxes.



Now I'll deoxit red and gold them before using it.


----------



## OctavianH

Those look great. When you have the chance to listen to them tell us what you think.


----------



## UntilThen

The Radiotron 807 is in first. I'll let it warm up for 30 mins before I start listening. In the meantime I'll have dinner. Here's a photo of them in the Elekit TU-8200 fired up.


----------



## UntilThen

So many on eBay. Be sure to buy a pair before the price jack up. I paid AUD $100 for a pair of Radiotron 807 and AUD $100 for a pair of Sylvania 807.

https://www.ebay.com.au/sch/i.html?...&LH_PrefLoc=2&_osacat=0&_odkw=Cossor+807+tube


----------



## OctavianH

I have a pair, RCA 807 bought with 80EUR from Germany. I am not buying from UK anymore due to Brexit. But Germany and France have a lot of tubes to find. 






Anyway, I am more and more conviced to remain on octals without top cap, working natively in Eternity. No adapter is best adapter and I have a lot to try. So these and all with top cap are low prio for me.


----------



## UntilThen

OctavianH said:


> Anyway, I am more and more conviced to remain on octals without top cap, working natively in Eternity. No adapter is best adapter and I have a lot to try. So these and all with top cap are low prio for me.


Wait till I tell you how they sound.


----------



## hpamdr

UntilThen said:


> Wait till I tell you how they sound.


@SonicTrance unless DL have sent 807 and adapter to Tomas...


----------



## SonicTrance

hpamdr said:


> @SonicTrance unless DL have sent 807 and adapter to Tomas...


Nope. His amp is now packed up and on its way to him  

I'd also recommend the octal version of the 807, the 6BG6. Or better yet the Russian version 6P7S. They're not exactly the same tube as 807 but very close and are very linear tubes when triode connected. I use the 6P7S in the silver version of Citadel.


----------



## hpamdr

SonicTrance said:


> Nope. His amp is now packed up and on its way to him
> 
> I'd also recommend the octal version of the 807, the 6BG6. Or better yet the Russian version 6P7S. They're not exactly the same tube as 807 but very close and are very linear tubes when triode connected. I use the 6P7S in the silver version of Citadel.


I will try to get some when my amp will be on the road unless 20ma at 200V is not linear enough... I also like russian tube specially before 1970


----------



## OctavianH

SonicTrance said:


> Nope. His amp is now packed up and on its way to him



He is lucky. By the way, I've seen you tried KT66 and also the 7581A. How do you see them in Infinity? (the 7581A)


----------



## hpamdr

OctavianH said:


> He is lucky. By the way, I've seen you tried KT66 and also the 7581A. How do you see them in Infinity? (the 7581A)


He is so lucky that you feel more and more close to get yours


----------



## OctavianH

hpamdr said:


> He is so lucky that you feel more and more close to get yours



I am patient. It is a desire but also a stress factor. Because the first months you just try and measure and try... I would gladly skip that to the "musical enjoyment" part.


----------



## SonicTrance

hpamdr said:


> I will try to get some when my amp will be on the road unless 20ma at 200V is not linear enough... I also like russian tube specially before 1970


That is a good operating point.



OctavianH said:


> He is lucky. By the way, I've seen you tried KT66 and also the 7581A. How do you see them in Infinity? (the 7581A)


I didn't listen much to each tube. Just dailed in the bias points for them. I listened to KT66 the most. Then EL12sp and also EL32 which I really liked. I did not roll input tube other than to find bias points. Just used the 6J5's.


----------



## OctavianH

SonicTrance said:


> I didn't listen much to each tube. Just dailed in the bias points for them. I listened to KT66 the most. Then EL12sp and also EL32 which I really liked. I did not roll input tube other than to find bias points. Just used the 6J5's.



I asked because I've just measured them, and they do not quite measure the same as KT66, even if you put the same bias for them @40mA. I am curious to know what bias you will decide for these at 20mA. But a lot of strange things happened during measurements, because several pairs were not matching my expected values...


----------



## SonicTrance

OctavianH said:


> I asked because I've just measured them, and they do not quite measure the same as KT66, even if you put the same bias for them @40mA. I am curious to know what bias you will decide for these at 20mA. But a lot of strange things happened during measurements, because several pairs were not matching my expected values...


The 7581's did run slightly cooler than the KT66 at the same bias point. Not enough to separate IMO.


----------



## OctavianH

SonicTrance said:


> The 7581's did run slightly cooler than the KT66 at the same bias point. Not enough to separate IMO.



Exactly, the 7581A were measured to have lower bias than KT66 up to 2V (-19V vs -21V in extreme cases). This means 7581A at KT66 bias would run cooler having smaller current.

In the meantime I started some burn in. Heard some ocassional crackles and sounds but seems that all will be good in the end.


----------



## UntilThen

OctavianH said:


> In the meantime I started some burn in. Heard some ocassional crackles and sounds but seems that all will be good in the end.


Yup tubes does that when used for the first time. They have the occasional hiss and crackles. Started on my Sylvania 807 today because i'm curious if it did sound different from the Radiotron 807. I have 2 sets of adapters so I use them all.  Initial listen show that both brands sound very similar but this is very early hours on both tubes. I'll probably need 3 months to burn in all my NOS tubes and Elekit TU-8200 is doing all the work for Odyssey.


----------



## hpamdr

SonicTrance said:


> That is a good operating point.
> 
> 
> I didn't listen much to each tube. Just dailed in the bias points for them. I listened to KT66 the most. Then EL12sp and also EL32 which I really liked. I did not roll input tube other than to find bias points. Just used the 6J5's.


I also like EL32 for the sweet tone, refined details and modest size. It really deserve the try unless you want deep sharp bass  In F.A i pair with EL11 or 6M6 and have good match.


----------



## OctavianH

hpamdr said:


> I also like EL32 for the sweet tone, refined details and modest size. It really deserve the try unless you want deep sharp bass  In F.A i pair with EL11 or 6M6 and have good match.



I find EL32 very airy and good on vocals. Wide soundstage. Are you using them as drivers or powers?


----------



## hpamdr (Mar 17, 2021)

OctavianH said:


> I find EL32 very airy and good on vocals. Wide soundstage. Are you using them as drivers or powers?


I was using them in both but as the amplification factor is not good and only working with sensible headphone. It turns now that I only use them as power and it keep the amp really cool.  
// With eternity and infinity it will only works in power position.


----------



## UntilThen

I still have one pair of Mullard EL32 smoke glass, shoulder glass shape.


----------



## DecentLevi

Hey guys I lost notifications for this thread and am sidetracked with business recently...
Is there a dedicated chart for Infinity with updated bias adjustments, that Tomas posted a few days ago?  He posted them here... but some of them don't show the mA / current amount. So how do I know what the current is for those - is that included on a sheet or is it a 'standard value'?


----------



## DecentLevi

And any recommendations for which brand / type of Volt Meter to get? But not too costly.


----------



## OctavianH

DecentLevi said:


> Hey guys I lost notifications for this thread and am sidetracked with business recently...
> Is there a dedicated chart for Infinity with updated bias adjustments, that Tomas posted a few days ago?  He posted them here... but some of them don't show the mA / current amount. So how do I know what the current is for those - is that included on a sheet or is it a 'standard value'?



I have put what Tomas said there in this table. From what I have understood from him, for input tubes you have 180V 4mA unless specified otherwise and for output tubes you have 200V 40mA unless specified otherwise.

Output tubes Infinity *200Va, 40mA* Ia
KT66/7581A: -17.3
EL39: -10.0
EL38: -9.0
EL12sp Tesla: -7.8
EL12 spez Telefunken: -6.7
EL3N: -3.9 *@ 35mA*
EL32: -11.7 *@ 35mA*
EL12: -6.2

Input tubes Infinity @ *180Va, 4mA* Ia
6J5/6C5/6SN7: -6.30
EL11: -7.80
6N7 in 6J5 sockets: -3.65
6N7 in 6SN7 socket: -2.35
E88CC: -4.90
E80CC: -3.80
12AV7: -4.50
6CG7: -6.20
MHLD6: -7.55
6SL7: -765mV *@ 3mA*

Now, I expect he sent you a table printed in the box of the amplifier.



DecentLevi said:


> And any recommendations for which brand / type of Volt Meter to get? But not too costly.



I would say any Voltmeter will do, even this one. You will measure DC Voltage with it on the 200 scale. That's all.


----------



## hpamdr (Mar 18, 2021)

DecentLevi said:


> And any recommendations for which brand / type of Volt Meter to get? But not too costly.


Hi DL, if you want the best get Fluke with calibration but this is over priced >250$. Any chinese DMM around 30$ can also do the job as we do not need to be ultra precise measure. Or in the middle with calibration certificate but as Fluke, you will have to get testing Leads.

About measure for infinity :
200V on Anode 40mA for output (except EL32,EL3N 35ma)
180V on Anode 4mA for input ( except 6SL7 3ma)

Form your measurement point Black/red on the right you just have to measure negative bias voltage as descibed by Tomas or on Firsts post document maintained by OctavianH.


----------



## OctavianH

Burning in some "outputs". GEC KT66 and K-R 6L6GAY. And I've had a little bit of sun after several days of "wrong" weather.


----------



## SonicTrance

Beautiful tubes!


----------



## OctavianH

Friday Beerday, guys!


----------



## hpamdr

Prosit...


----------



## OctavianH

Beautiful ladies, I bet they taste nice.


----------



## UntilThen

My poison


----------



## OctavianH

That looks very healthy. It depends on what it is inside. It reminds me of cycling which is a noble sport.


----------



## hpamdr

OctavianH said:


> Beautiful ladies, I bet they taste nice.


Got also some old fivre 12SL7GT roundplate 3 flavors..


----------



## UntilThen

I was going to buy some 6SL7 from my supplier soon. Sylvania, Brimar, RCA, etc. Unfortunately I'm not using 12 volts.


----------



## OctavianH

My pair of Fivre 6N7G will arrive most probably on Monday. Let's hope those will be functional. And to tell the story for others, I've bought a pair of Fivre 6N7G at a very small price because they were "unopened, untested, maybe not functional". But for 31.5 EUR I gladly took the risk.






We will see when they arrive if at least one of them works, so I can try these on Eternity when it will arrive. If I am lucky enough both will work.

Since the UK went on Brexit and I have to pay additional taxes (around 20%) I started to look on Germany and France for tubes and found several good deals.


----------



## hpamdr

OctavianH said:


> My pair of Fivre 6N7G will arrive most probably on Monday. Let's hope those will be functional. And to tell the story for others, I've bought a pair of Fivre 6N7G at a very small price because they were "unopened, untested, maybe not functional". But for 31.5 EUR I gladly took the risk.
> 
> 
> 
> ...


About UK here in France It depends of total price if it is declared less than 50€ taxes are not taken anymore ! And the parcel arrives in a week


----------



## OctavianH

hpamdr said:


> About UK here in France It depends of total price if it is declared less than 50€ taxes are not taken anymore ! And the parcel arrives in a week



Here at my latest Langrex order I had to make a visit to the customs. They are not in proximity because there is only one postal office with customs department in town and due to covid the number of persons inside the office was limited. In short, I had to sit in the snowing morning for half an hour at 9AM so the guys will allow me inside. Then I had to declare what I receive, to pay a small tax for the hosting and then VAT for the whole order. The whole deal was around 20% but indeed much over 50 EUR. So I said "Thanks, but no thanks." I have enough british tubes.


----------



## hpamdr (Mar 26, 2021)

UntilThen said:


> Unfortunately I'm not using 12 volts.


But you can get many 6V version 
About RCA this is not the best choice IMO unless you get early versions 40-50'.  I have 3 pairs of old RCA VT-231 grey glass which sound good dark sound, a bit slow with a small veil.
It is not SL  version anyway...


----------



## hpamdr

@SonicTrance
About 6L6 and 6L6GC version typical plate voltage is 250V so for eternity and infinity, both tubes should be usable...
For Odyssey, as it is a completely different amplifier and probably with automatic bias the tube rolling info are not relevant. Voltage should be higher to give more POWER.


----------



## SonicTrance

hpamdr said:


> @SonicTrance
> About 6L6 and 6L6GC version typical plate voltage is 250V so for eternity and infinity, both tubes should be usable...
> For Odyssey, as it is a completely different amplifier and probably with automatic bias the tube rolling info are not relevant. Voltage should be higher to give more POWER.


Yes, both versions are fine in Eternity as the anode voltage is 200V. In Odyssey it'll be 450V so can't run 6L6.


----------



## OctavianH

I always knew my gay tubes are sensible, and now I understood why: plate voltage.


----------



## UntilThen

Hi Tomas, can I use this wonderful looking Western Electric 420a with adapter in Odyssey?
https://www.stereo.net.au/forums/to...x7-or-12at7-tubes-with-adaptors-nos-nib-pair/

I already have a pair of those tubes from the same seller previously but I will get another pair as it comes with the adapters. Are these superior to 12ax7 and 12at7?


----------



## hpamdr

@SonicTrans
I have a tube between EL32 and 6J7G spec where bias for input is like -17.5V for 4mA at 180V or 5.5ma at -15V is it possible to extend a bit grid voltage range  [-20 - 0]V in input stage ?


----------



## SonicTrance

UntilThen said:


> Hi Tomas, can I use this wonderful looking Western Electric 420a with adapter in Odyssey?
> https://www.stereo.net.au/forums/to...x7-or-12at7-tubes-with-adaptors-nos-nib-pair/
> 
> I already have a pair of those tubes from the same seller previously but I will get another pair as it comes with the adapters. Are these superior to 12ax7 and 12at7?


It'll work. I have no idea if they'll sound better than 12AX7 or 12AT7 though.



hpamdr said:


> @SonicTrans
> I have a tube between EL32 and 6J7G spec where bias for input is like -17.5V for 4mA at 180V or 5.5ma at -15V is it possible to extend a bit grid voltage range  [-20 - 0]V in input stage ?


Sure, I can give you -23 - 0 on the input stage if you want. Downside is that the adjustment becomes more sensitive. You just have to be careful while adjusting.


----------



## hpamdr

SonicTrance said:


> It'll work. I have no idea if they'll sound better than 12AX7 or 12AT7 though.
> 
> 
> Sure, I can give you -23 - 0 on the input stage if you want. Downside is that the adjustment becomes more sensitive. You just have to be careful while adjusting.


@SonicTrance
How many turn in the trimer do we have to adjust bias in input and in output ?


----------



## SonicTrance

hpamdr said:


> @SonicTrance
> How many turn in the trimer do we have to adjust bias in input and in output ?


Both are 10 turn trimmers.


----------



## hpamdr

@SonicTrance 
That means precision is 0.125V Output/ 0.064V Input for 10° if i consider 4.5V/2.3V by turn. This is precise enough !


----------



## SonicTrance

hpamdr said:


> @SonicTrance
> That means precision is 0.125V Output/ 0.064V Input for 10° if i consider 4.5V/2.3V by turn. This is precise enough !


I'm sure that's accurate 
So you want the -23 - 0V input stage adjustment?


----------



## hpamdr

SonicTrance said:


> I'm sure that's accurate
> So you want the -23 - 0V input stage adjustment?


Yes !


----------



## SonicTrance

hpamdr said:


> Yes !


You too @OctavianH ?


----------



## OctavianH

Honestly I do not really know what I can do with it. For what I want to use -10V grid bias is enough. What I can imagine is that having this will allow me to use some output tubes on the inputs. Is there any other advantage?


----------



## SonicTrance

OctavianH said:


> Honestly I do not really know what I can do with it. For what I want to use -10V grid bias is enough. What I can imagine is that having this will allow me to use some output tubes on the inputs. Is there any other advantage?


No other advantage. The disadvantage is higher sensitivity on the adjustment.


----------



## OctavianH

SonicTrance said:


> No other advantage. The disadvantage is higher sensitivity on the adjustment.



Then no. I guess I am fine with 0-10V.


----------



## OctavianH

Guys, someone has to try these But of course, not me, need adapter and I am still in my "no adapter" mood.


----------



## SonicTrance

OctavianH said:


> Guys, someone has to try these But of course, not me, need adapter and I am still in my "no adapter" mood.


They're very good tubes. I got a bunch myself. Basically they're half a 6SN7 with a grid and anode cap.


----------



## UntilThen

Reminds me of the 596 rectifier which I'll be getting.


----------



## UntilThen

EL39 are brand new in the box. So perfect like it just left the factory. Wonder what year it's manufactured in? Words on the base of tube says EL39-56.37 and on the box its says 11-56. Is it made in 1956? Grey paint is similar to the Philip Miniwatt EL3N red paint. I imagine the paint will fall off easily and then it will be ugly.


----------



## UntilThen

Next to the Sylvania 807.   The 807 is better constructed. Thicker glass, gold plated pins. EL39 is kind of plain Jane apart from the paint. Both are brand new but one of the 807 took out my Elekit TU-8200.


----------



## UntilThen

RT EL39 and Telefunken EL12 spez.


----------



## hpamdr (Mar 28, 2021)

UntilThen said:


> EL39 are brand new in the box. So perfect like it just left the factory. Wonder what year it's manufactured in? Words on the base of tube says EL39-56.37 and on the box its says 11-56. Is it made in 1956? Grey paint is similar to the Philip Miniwatt EL3N red paint. I imagine the paint will fall off easily and then it will be ugly.


56.37 on tube means 37'week of 1956 for build and 11-56 on the box mean packed in November 56.
Mine have no Box


----------



## OctavianH

I've just received my pair of Fivre 6N7G. Unopened, seem unused. Let's hope these work. Now I have to think how to measure these with DuoVac. I think that I can measure each triode exactly like with 6J5 (A2/G2/K2 and then A1/G1/K1). For the triodes in parallel I think I just have to link A1+A2 and G1+G2. There is a common cathode so it remains single. Brrr, am I right @hpamdr ?





I never understood why these guys are putting those papers on them. But they look quite nice.


----------



## hpamdr

OctavianH said:


> I've just received my pair of Fivre 6N7G. Unopened, seem unused. Let's hope these work. Now I have to think how to measure these with DuoVac. I think that I can measure each triode exactly like with 6J5 (A2/G2/K2 and then A1/G1/K1). For the triodes in parallel I think I just have to link A1+A2 and G1+G2. There is a common cathode so it remains single. Brrr, am I right @hpamdr ?


Yes you are right about the 3 measures T1 ( A1/G1/K), T2 (A2/G2/K), T1+T2 (A1+A2,G1+G2, K)for each tube.
I do not know if DuoVac measure in same time Va and Vs if yes you can measure both triode at once.
Set Va = Vs = 180 or 200V before stating measure.
plug: from tube pin to measure plugs  
K -> K
G1 and G2 -> G
A1 -> A
A2 -> S (g2)



OctavianH said:


> I never understood why these guys are putting those papers on them. But they look quite nice.


Italian like a lot those paper in tube... Most of the tube for administration in Italy have such label...


----------



## OctavianH

hpamdr said:


> Yes you are right about the 3 measures T1 ( A1/G1/K), T2 (A2/G2/K), T1+T2 (A1+A2,G1+G2, K)for each tube.
> I do not know if DuoVac measure in same time Va and Vs if yes you can measure both triode at once.
> Set Va = Vs = 180 or 200V before stating measure.
> plug: from tube pin to measure plugs
> ...



Well, I've tried to measure each triode and worked. Just exchanged pin 3->6 for anodes and pin 4->5 for grids.





But then I said, let's measure as if inserted in Eternity in the 6J5 slots, so I just connected A1+A2 and G1+G2 and it worked:





With this type of connection I measured around -3.5V decent current around 4mA:









I think I would put the bias to -3.6V to be sure the second one does not go too high over 5mA. Anyway, putting triodes in parallel somehow compensated the unmatching. Maybe this is why on Elise you do not really care to pair anything and it will somehow work. Yep folks, these are my findings. Many thanks for help.

In the end, a picture with the "decorations". Ministero Delle Finanze!


----------



## UntilThen

OctavianH said:


> I've just received my pair of Fivre 6N7G. Unopened, seem unused. Let's hope these work. Now I have to think how to measure these with DuoVac. I think that I can measure each triode exactly like with 6J5 (A2/G2/K2 and then A1/G1/K1). For the triodes in parallel I think I just have to link A1+A2 and G1+G2. There is a common cathode so it remains single. Brrr, am I right @hpamdr ?
> 
> 
> 
> I never understood why these guys are putting those papers on them. But they look quite nice.



I have a pair of these and they are in storage. Don't know what to do with them now.


----------



## hpamdr (Mar 29, 2021)

@OctavianH So easy to have fun 
@UntilThen keep them you should be able to use in odyssey or other amps with 6n7 -> 6sn7 adapter.


----------



## OctavianH

UntilThen said:


> I have a pair of these and they are in storage. Don't know what to do with them now.



Keep them because these seem to be quite nice tubes. By the way, I've seen your pictures with LCD-3 and I have to ask you: how to you see LCD-3 vs T1.2? Both seem to be warm and forgiving headphones but you sold T1 and you kept LCD-3. I guess you like these more.


----------



## UntilThen

hpamdr said:


> @OctavianH So easy to have fun
> @UntilThen keep them you should be able to use in odyssey or other amps with 6n7 -> 6sn7 adapter.



Good point. I have forgotten that I actually use 6n7g > 6sn7 in GOTL. Nice strong gain. I'll keep in mind for Odyssey.



OctavianH said:


> Keep them because these seem to be quite nice tubes. By the way, I've seen your pictures with LCD-3 and I have to ask you: how to you see LCD-3 vs T1.2? Both seem to be warm and forgiving headphones but you sold T1 and you kept LCD-3. I guess you like these more.



2 reasons why I prefer LCD-3f over Beyer 1.2

1. Comfort. I can't get over Beyer's round ear cups. They don't cover over your ears and it's not comfortable.

2. I like the clearer treble presentation in LCD-3f. Beyer T1.2 seem a bit roll off in the treble region. I also prefer the planar bass but Beyer bass shines when you power it from a powerful amp. I remember hearing Beyer T1.2 off the Sansui 907mr. It was an eye opener. Ultimately I prefer LCD-3f overall tone over Beyer T1.2.

I sold off Beyer T1.2 at half price and it was still very new.


----------



## OctavianH

UntilThen said:


> 2 reasons why I prefer LCD-3f over Beyer 1.2
> 
> 1. Comfort. I can't get over Beyer's round ear cups. They don't cover over your ears and it's not comfortable.
> 
> ...



1) is not problematic to me but 2) it is a very interesting point. I wonder how T1.2 will sound on Eternity since I quite love them on Elise. But yes, LCD-3 is an interesting headphone.


----------



## UntilThen

OctavianH said:


> 1) is not problematic to me but 2) it is a very interesting point. I wonder how T1.2 will sound on Eternity since I quite love them on Elise. But yes, LCD-3 is an interesting headphone.



I remember Beyer T1.2 sound very good with Oblivion. Similarly Verite Open. I will never know why I sold off those headphones. Someday, I will get another ZMF headphone.


----------



## OctavianH

Guys, let's not forget why the "Tube rolling off" switch exists. I've refilled the basket!


----------



## jonathan c

OctavianH said:


> Guys, let's not forget why the "Tube rolling off" switch exists. I've refilled the basket!


No adapters necessary!


----------



## hpamdr

Looking for matched triodes in double triode tube..


----------



## OctavianH

You're right, I have to measure my 6F8Gs and 7N7s. I think I can measure them with the DuoVac set to 6SN7 in their adapters to 6SN7. Am I missing something?


----------



## hpamdr

When you use adapter, you measure like if you inserted 6sn7. But you have to verify first that the adapter do not strap triodes together with a DMM. (Normally not for 7N7 and 6F8G but pay attention with dedicated adapter for F.A. amp)


----------



## OctavianH

hpamdr said:


> When you use adapter, you measure like if you inserted 6sn7. But you have to verify first that the adapter do not strap triodes together with a DMM. (Normally not for 7N7 and 6F8G but pay attention with dedicated adapter for F.A. amp)



My adapters are generic, not for Elise. I plan to measure these and use them in Eternity:









These are one of my favourite drivers. I have to admit that except Foton 6H8C and Psvane CV181T2 I could not say I am a 6SN7 lover. These are better for me than those. Of course I like a lot the Sylvania 6SN7GTB and RCA 5692:









Anyway, I might measure and try also my VT-231 pairs from RCA and Ken-Rad.









Basically this is my "6SN7" arsenal I like. Not many, but some decent ones. However, I expect these to be surpassed by 6J5. We will see.


----------



## hpamdr

very nice tubes !
6SN7 have many flavors and with eternity, you will just have to search for tube with internally matched triode..
Just some fun with duovac


----------



## OctavianH

I will do it. Today I just measure the distance from my mouth to my beer pint which after several tries seems optimal when tends to 0. LOL

Ah, and I watch this video, I think I've seen it already 20 times.


----------



## UntilThen

I have the same adapter for my Tung Sol 6F8G black glass round plates. The adapters were from Poland - no connections with Felliks Audio. Very well made adapters. I had them for many years now. Here I'm using it in my Wa22 and it's quiet. No noise at all.


----------



## OctavianH (Apr 2, 2021)

UntilThen said:


> I have the same adapter for my Tung Sol 6F8G black glass round plates. The adapters were from Poland - no connections with Felliks Audio. Very well made adapters. I had them for many years now. Here I'm using it in my Wa22 and it's quiet. No noise at all.



Yes, the adapters are top class. There is a guy in Poland called on Ebay piotrdoor and he is making these adapters. I have bought from him several pairs of 6F8G->6SN7 and I have also EL32->6V6 and EL38->6V6. I am not sure why he is not very interested anymore in making more adapters, I've asked him for others. Anyway, these are the best adapters I have.

Later edit: These adapters appeared also on some speaker amplifiers made by Feliks Audio. On the old F.A. website I was able to see some of them, but now they upgraded the website and removed those amplifiers.


----------



## OctavianH (Apr 3, 2021)

Gaining a little bit of confidence from the measurements of Chris, I started today to measure my double triodes mentioned yesterday. All are quite good matched, except 2 special cases, but luckily for me, I found at least one from each type very well matched.

So, more fun with DuoVac!






My values were around -6.5V to -7V for the operating point we want to use in our amps.





And the winners are:





Now, comparing these with the values proposed by Tomas, who set the -6.3V as the bias for 6SN7, I would say mine were higher, meaning that these tubes might exceed 5mA on the amplifier with his bias proposal according to my measurements. I've seen that he prefers to run them "strong". Looking at the measuremens of @hpamdr I see his piece of 7N7 needed -6.3V like Tomas said. So, I have to see if I am doing something wrong here.


----------



## hpamdr

OctavianH said:


> Gaining a little bit of confidence from the measurements of Chris, I started today to measure my double triodes mentioned yesterday. All are quite good matched, except 2 special cases, but luckily for me, I found at least one from each type very well matched.
> 
> So, more fun with DuoVac!
> 
> ...


Measure is really fun, but a bit less when you discover that what you got long time ago is not exactly what was described....
Keep in mind that i buy many tubes not NOS but a bit used normally above 80% 
I have others 7N7 and VT-231 I measured above 6.5 and 6N7G above 7V. _(I will also see if i need to re-calibrate the tracer)_
I've almost convinced my friend that i need to keep current uTracer and that he need a better one


----------



## OctavianH

hpamdr said:


> Measure is really fun, but a bit less when you discover that what you got long time ago is not exactly what was described....
> Keep in mind that i buy many tubes not NOS but a bit used normally above 80%
> I have others 7N7 and VT-231 I measured above 6.5 and 6N7G above 7V. _(I will also see if i need to re-calibrate the tracer)_
> I've almost convinced my friend that i need to keep current uTracer and that he need a better one



In this case I would say we need to revisit the 6SN7 bias to -6.5V to be safe. And that you should change your job to sales/marketing because you convince a lot of people to buy stuff, and many of them are happy. Look at me with my DuoVac. You were born to be a successful salesman!


----------



## hpamdr

OctavianH said:


> In this case I would say we need to revisit the 6SN7 bias to -6.5V to be safe. And that you should change your job to sales/marketing because you convince a lot of people to buy stuff, and many of them are happy. Look at me with my DuoVac. You were born to be a successful salesman!


Not really 
To be safe, we have a known target but should under bias and fine tune to the best with tube on socket !


----------



## OctavianH (Apr 3, 2021)

hpamdr said:


> Not really
> To be safe, we have a known target but should under bias and fine tune to the best with tube on socket !



I have that "fixed bias" switch but I think I'll ask Tomas to set it for input at -6.6V to be able to use my L63 without problems. For weaker tubes I think I'll use the variable bias and lower it a little bit. I'll think about this. The best would be to be able to adjust both variable and fixed bias trimmers. But I am not sure this is possible.

@SonicTrance What do you think?


----------



## SonicTrance

OctavianH said:


> I have that "fixed bias" switch but I think I'll ask Tomas to set it for input at -6.6V to be able to use my L63 without problems. For weaker tubes I think I'll use the variable bias and lower it a little bit. I'll think about this. The best would be to be able to adjust both variable and fixed bias trimmers. But I am not sure this is possible.
> 
> @SonicTrance What do you think?


I can set it at -6.6V no problem. The fixed bias is also adjustable but with a trimmer on the inside. I can guide you if you ever want to adjust it.


----------



## OctavianH (Apr 3, 2021)

SonicTrance said:


> I can set it at -6.6V no problem. The fixed bias is also adjustable but with a trimmer on the inside. I can guide you if you ever want to adjust it.



Yep, according to my measuremens my best medium values for fixed bias are *Input=-6.6V* and *Output=-21V *(for 6SN7/KT66 and all equivalents).
I measured what currents will have several tubes when -21V is set as bias and KT66 are fine (at the top limit) but the 6L6 are under 15mA.
For mostly 6SN7/7N7/6F8G the -6.6V is fine. It is not clear to me how on Levi's amplifier KT66 and 7581A/6L6 worked well at the same bias.





If I will ever want to adjust it, what panel I have to unmount? Is there any way to make it more accessible?


----------



## SonicTrance

OctavianH said:


> Yep, according to my measuremens my best medium values for fixed bias are *Input=-6.6V* and *Output=-21V *(for 6SN7/KT66 and all equivalents).


Alright, I'll set your output "stock bias" to -21V also.



OctavianH said:


> It is not clear to me how on Levi's amplifier KT66 and 7581A/6L6 worked well at the same bias.


The 7581A did run slightly cooler than the KT66 at the same bias point. The difference was so little I did not think it was worth a own spot. There will always be differences from tube to tube of course.



OctavianH said:


> If I will ever want to adjust it, what panel I have to unmount?


Unscrew 4 screws and take off bottom panel. 



OctavianH said:


> Is there any way to make it more accessible?


I've just finished that stage and the bias switches are all wired up. It was very time consuming so I'd say no to that  
What's the point of having a fixed bias switch if you want it easy adjustable? Just use the adjustable one at the top plate?


----------



## OctavianH (Apr 3, 2021)

SonicTrance said:


> I've just finished that stage and the bias switches are all wired up. It was very time consuming so I'd say no to that
> What's the point of having a fixed bias switch if you want it easy adjustable? Just use the adjustable one at the top plate?



Yep, you're right. If 4 screws are all it has to be done, I'll ask you if needed (otherwise I'll adjust other trimmer and destroy your work LOL).
-21V seems fine to me for the tubes I have. As you see, the "strongest" GEC KT66 goes up to 23.6mA but all others are below. So it seems fine for me. If you think we are too close to 24mA and there is a risk for the fuse to blow, set it to -21.2V or -21.4V and it should be also fine. I let you decide. Of course, I am interested to know if at -21V on your tests the KT66 work fine.


----------



## SonicTrance

OctavianH said:


> Yep, you're right. If 4 screws are all it has to be done, I'll ask you if needed (otherwise I'll adjust other trimmer and destroy your work LOL).
> -21V seems fine to me for the tubes I have. As you see, the "strongest" GEC KT66 goes up to 23.6mA but all others are below. So it seems fine for me. If you think we are too close to 24mA and there is a risk for the fuse to blow, set it to -21.2V or -21.4V and it should be also fine. I let you decide. Of course, I am interested to know if at -21V on your tests the KT66 work fine.


Ok great! =)

Maybe tonight I can test the output stage for the first time. I'll let you know!


----------



## OctavianH

SonicTrance said:


> Maybe tonight I can test the output stage for the first time. I'll let you know!



Yep, in the meantime I try to determine myself to stop listening to my pair of  KT88 so I can measure it again but it sounds so good.





The reason for my need to remeasure these KT88 is that last time I found a grid bias of -21.6V. This cannot be fine, since KT88 have to dwell around -25V according to the datasheets. If -21.6V is fine, it means I can use GEC KT66 and this pair of Psvane KT88T2 with the fixed grid bias, which is something which doesn't sound fine to me.
Another thing I might do is to measure my other pair of KT88 from Shuguang and let them turned on for around 10 minutes to be sure they are warmed enough. These KT88 seem slow starters when measured (same for 6550A).


----------



## SonicTrance

OctavianH said:


> The reason for my need to remeasure these KT88 is that last time I found a grid bias of -21.6V. This cannot be fine, since KT88 have to dwell around -25V according to the datasheets.


Doesn't seem right. KT88 should draw around 40mA @ -20Vg, 200Va.


----------



## SonicTrance

@OctavianH 
The Gold Lion KT66 pulls 20mA @ -23.5Vg, 200Va. That's very unexpected. You still want the stock bias @ -21V?


----------



## OctavianH (Apr 3, 2021)

SonicTrance said:


> @OctavianH
> The Gold Lion KT66 pulls 20mA @ -23.5Vg, 200Va. That's very unexpected. You still want the stock bias @ -21V?



Yep. There's something "fishy" with those KT66. According to the datasheet the Vg should be lower.

Later edit:

Check this


----------



## SonicTrance

OctavianH said:


> Yep. There's something "fishy" with those KT66. According to the datasheet the Vg should be lower.


Yes it might be something off with how they bias. I don't have any vintage KT66 to test with sadly. The voltage should be higher  Closer to 0V is higher.


----------



## OctavianH

These new production tubes are measuring strange and differently than what we expect. I had the same problem with the Psvane KT88T2. I think I have to trust my own measurements.


----------



## hpamdr

OctavianH said:


> These new production tubes are measuring strange and differently than what we expect. I had the same problem with the Psvane KT88T2. I think I have to trust my own measurements.


My russian KT88 GL measure around Ia 40mA for 200V Va at -20V Vg and 20mA at -24V Vg .. But most tube do not measure the same. As usual, we just have to find best compromise.. We should be lucky to be able to bias with such precision. The Ampmeter in the amp should be calibrated if we want precise measure, but we just have to keep in mind that *the goal is to have the amp sound good *and this is right inside a larger range !


----------



## OctavianH (Apr 4, 2021)

hpamdr said:


> My russian KT88 GL measure around Ia 40mA for 200V Va at -20V Vg and 20mA at -24V Vg .. But most tube do not measure the same. As usual, we just have to find best compromise.. We should be lucky to be able to bias with such precision. The Ampmeter in the amp should be calibrated if we want precise measure, but we just have to keep in mind that *the goal is to have the amp sound good *and this is right inside a larger range !



During my measurements I observed that the variation of the current at 0.1V grid bias is around 0.2mA for inputs, but these KT88 jump around 0.4mA. This means that the range cannot be very big, since an increase of -1V grid bias might add 4mA. More than this these KT88 are slow starters, in around 2minutes they reach a quite stable current around 80% of what they can produce, but in the next 10 minutes the current continues to rise slowly, so I think we need to keep these at lower current (higher grid bias) when we start the amplifier, to bias around 18mA or less, to be sure we are not going up in time.

Today my focus is to analyze my KT88 and maybe, if I will have time, 6550A and KT77. All of these seemed similar to me in terms of slow starting when I measured them last time. But at that time I was in a hurry, today I'll spend more time with them. I will come back with my conclusions.


----------



## OctavianH (Apr 4, 2021)

OK, back with my conclusions. Both pairs of KT88 I have are biasing around -22V. So for me -22.5V before I start the amplifier seems a safe value.
For KT66 a medium value remains -21V. I think these will be the values I will use here. 6L6 are around -19V and 6V6 around -14V.
And for fun I measured also the pair of KT150 which went, as expected, around -25V for 200V/20mA.





If you guys find others or think I am wrong here please advise.

How can I check if the DuoVac is calibrated properly? Maybe measuring with a DMM in the socket pins without any tube inserted at plate and cathode for Va? and grid and cathode for Vg1?


----------



## UntilThen

Tony my tube supplier send over photos of the GEC KT77 and Tung Sol 6550 and got me really excited.



I've also pick up this pair of Mullard 6201 / 12AT7. NOS NIB. They are AUD$220. They will be part of my drivers for Odyssey. I have no idea how they will sound. Brilliant I hope.


----------



## hpamdr (Apr 9, 2021)

OctavianH said:


> OK, back with my conclusions. Both pairs of KT88 I have are biasing around -22V. So for me -22.5V before I start the amplifier seems a safe value.
> For KT66 a medium value remains -21V. I think these will be the values I will use here. 6L6 are around -19V and 6V6 around -14V.
> And for fun I measured also the pair of KT150 which went, as expected, around -25V for 200V/20mA.
> 
> ...


Hi Octavian,
Normally Alain Ducrocq calibrated the unit before sending and you can ask him how to do.

At first point, I suggest you trust Va/Vs values !
If you really want to "control" Ia/Is calibration, the easiest is to use a 10KOhms calibration resistor. If you do not have such, a 10K <=1% is also OK.
Connect it between Anode and Cathode you can use noval socket pin 1/4, you can also control at the same time Scrren with another 10KOhms connected between G2 and Cathode ex pin 6/9 of same noval socket. If you follow my proposed scheme,  use wires to connect cathode to  pin 4 and 6, Anode to pin 1 and G2 to pin 9.
Once connected, launch measures around 200V for each Va/Vs you should have Ia and Is worth the tenth of respective Va and Vs_ (i.e. 20ma for 200V)_.
Check that the tenth ratio is kept on a wider range from 100V to 400V for both Va and Vs.

With a calibrated voltmeter, you can control grid voltage between Cathode and Grid directly put your probe on measuring plugs.

To control Anode/Screen Voltage it will be more difficult as the emission is done by impulse and even with T-RMS DMM not sure if you will be able to capture it.


----------



## OctavianH

I do not think there is a problem with my calibration. I only observed differences between what Tomas found as grid bias and what I measured.

For example:

Genalex KT66 Russian = -23.5 (his measurement)
GEC NOS KT66 = -21 (my measurement)

Tung Sol 7581A russian = -20.4 (his measurement)
Tung Sol 7581A russian = -19.4 (my measurement)

Now, I know that all tubes measure differently, but in the case of the Tung Sol 7581A, those are identical and bought by me as a quad. So I doubt there should be a difference between them. It seems there is a difference of what we measure as current on the tester and what is the current on the amplifier, where the current is higher, therefore the grid bias value is bigger (further away from 0V).


----------



## hpamdr (Apr 9, 2021)

OctavianH said:


> Tung Sol 7581A, those are identical and bought by me as a quad.


Unfortunately even if you buy a matched quad it is very rare to get identical measure on each tube.
For me the goal of measure is to know tube state, be able to match as close as possible pairs and have an idea of the bias points. This is much precise than just looking on datasheet or using spice models.

In the amplifier we have to trust the amp meter to be on the supported range for having best sound for specific tubes. The amp is not a lab tool and the result is finnaly jugged on the Headphone. 

@SonicTrance
I do not know if the measure is exactly the same. In any case it is not that big let say 1V on power and 0.3 V on input. This can be due to some resistance in the path or not exactly same emission voltage.


----------



## SonicTrance

hpamdr said:


> I do not know the measure is exactly the same and in any case it is not that big let say 1V on power and 0.3 V on input. This can be due to some resistance in the path or not exactly same emission voltage.


Correct, it can be a number of things. It's not that important anyway. Just start with a slightly lower bias voltage and then fine tune once the tubes are in place. Easy.


----------



## SonicTrance

Since you guys like measuring I can tell you how the 200Va for the output tubes is set in Eternity.

The gyrator plate load output is set at 210V. This voltage is firm, always. Then you have a 470 ohm resistor from gyrator source (output) to the tube anode. It's this resistor that needs to drop between 7-14V for the gyrator to be happy.
Ohms law says that if you run the tube at 20mA the 470R resistor drops 9.4V. This will give you a Va of 210V - 9.4V = 200.6V.
If you instead run the tube at 15mA you get a Va of 203V. 

This is of no concern at all. Just thought I'd mention it to help you understand a little how the amp works.


----------



## OctavianH

SonicTrance said:


> Since you guys like measuring I can tell you how the 200Va for the output tubes is set in Eternity.



What I measure is very close to what we can deduce via datasheets.

For 6L6GC a little bit under -20... therefor my -19.4V is fine:





For GEC KT66 a little bit over -20... therefore my -21V:





I know the amplifier is not a test device, and the final truth will be measured directly on it, but I try to find a correlation between my measurements, what the datasheet advises and what was measured on the amplifier, to be able to determine some calculation rules like:

Vgrid = Vgrid measured on DuoVac-2V

Or Vgrid = Vgrid calculated on DS-2V

(these are just examples). When I will know how much the theory matches the behaviour on the amp I will able to predict what tubes to use, or understand if a tube type, via its datasheet, is usable. I think there is no 1:1 matching on what we can calculate/measure and what we will measure on the amplifier.


----------



## hpamdr (Apr 9, 2021)

SonicTrance said:


> Since you guys like measuring I can tell you how the 200Va for the output tubes is set in Eternity.
> 
> The gyrator plate load output is set at 210V. This voltage is firm, always. Then you have a 470 ohm resistor from gyrator source (output) to the tube anode. It's this resistor that needs to drop between 7-14V for the gyrator to be happy.
> Ohms law says that if you run the tube at 20mA the 470R resistor drops 9.4V. This will give you a Va of 210V - 9.4V = 200.6V.
> ...


If we have one gyrator by triode, that means that this mechanism tend to reduce unbalanced tubes between each side !
Am I right ?


----------



## OctavianH

English ladies visit me today. Friday beerday people.


----------



## SonicTrance

hpamdr said:


> If we have one gyrator by triode, that means that this mechanism tend to reduce unbalanced tubes between each side !
> Am I right ?


Unfortunately not. The gyrator plate loads are totally independent of each other. They also have nothing to do with tube bias. The gyrator loads the tube and provides a (flat) load line. The negative voltage at the grid then bias the tube.

In my balanced amps, Oblivion and Citadel, the bias is set with a CCS tail. Then the total current on each channel is always the same. One tube (there's a pair on each side) can still draw more than the other but the total remains the same.


----------



## OctavianH

Not bad this one.






Reminds me of:


----------



## SonicTrance

Swedish Norrlands Djup! Very nice!


----------



## OctavianH

SonicTrance said:


> Swedish Norrlands Djup! Very nice!



By the way Tomas, last time I visited Stockholm, and I think it is valid for all Sweden, they were not selling normal beer in the normal shops. There was a maximum of 3% alcohol on a normal shop if you were searching for a normal beer. I remember I had to go with my girl to a special beer shop to buy "normal" beer like I drink at home. And when I bought the beer the shop guy asked also her to come from outside to present her ID card because he asked me if I buy all that beer for me and I told we were two persons. This is still valid in Sweden? Quite strange for me, here you can buy beer without problem


----------



## SonicTrance

OctavianH said:


> By the way Tomas, last time I visited Stockholm, and I think it is valid for all Sweden, they were not selling normal beer in the normal shops. There was a maximum of 3% alcohol on a normal shop if you were searching for a normal beer. I remember I had to go with my girl to a special beer shop to buy "normal" beer like I drink at home. And when I bought the beer the shop guy asked also her to come from outside to present her ID card because he asked me if I buy all that beer for me and I told we were two persons. This is still valid in Sweden? Quite strange for me, here you can buy beer without problem


Yes! It's still valid. It's called "Systembolaget" and they have monopoly on selling alcoholic drinks with, like you said, over 3.5% alcohol.


----------



## OctavianH

SonicTrance said:


> Yes! It's still valid. It's called "Systembolaget" and they have monopoly on selling alcoholic drinks with, like you said, over 3.5% alcohol.



Good to know, I only visited Stockholm where I have some good friends and Malmo. But this rule seemed to be country wide. Sweden is full of a lot of heavy metal bands and that feeling of heavy metal and freedom but my friends told me that the real drinking goes on if you go on a ferry outside the country. It is strange for me since here everyone buys every alcohol they want and nobody cares. But I like ships because I do not have here so I took all the ships near Stockholm just to try them. LOL
I think you should visit me if you like beer, I have a feeling you will like here.


----------



## SonicTrance

OctavianH said:


> I think you should visit me if you like beer, I have a feeling you will like here.


I do like beer! So, maybe I'll visit you!


----------



## OctavianH

Do it!  I wait for you here. I have vampires, citadels, beer, steak. Not so bad isn't it?


----------



## OctavianH (Apr 10, 2021)

So back to our business. Measuring! 

I measured today my oldest pair of GEC KT66 clear glass with cup getter, dated September 1962 Hammersmith. This pair is quite unbalanced, exactly like the M-OV grey glass from '42 I measured some time ago. I wonder if the oldest production KT66 had a general problem because my other pairs of double halo getter from 70s are measuring much better and are quite closely matched. And I observed that usually new production tubes are much more stronger than NOS.





And the cup getter, better said "inverted cup" getter:





And I think I found the ideal anthem of UltraSonic Studios:



Yep, I like HammerFall, I've seen them in Wacken back in 2019 when things were normal. I've seen they plan to tour with Helloween in 2022 so I think I'll catch them in Prague. I like Prague, nice girls, good beer, good mexican food at a restaurant I like! And yes I like mexican food, spicy!


----------



## OctavianH

Just tried this scottish beer. Wow, so smoked. It seems the guys in Scotland like smoked beer.


----------



## OctavianH (Apr 11, 2021)

Just listening to the Black Sabbath remasters. 





KT88 and Foton 6H8C are my choosing for today.





These provide a full sound and quite complement the 70s recording. I am extremely pleased. Will try these on Eternity soon. There is no bigger band than Sabbath and no greater vocal than Ozzy. I remembered that!


----------



## OctavianH (Apr 10, 2021)

Going to my favourite track of all times which is Killing yourself to live from Sabbath Bloody Sabbath.





So yeah! We reach 1973 guys!





And yes, pure awesomeness, Tony Iommi is just floating with that solo. This is the absolute sound guys!

And yes, no Sabbath without Bill Ward! Leave it, no reunion or Sabbath without Bill Ward. That is not Sabbath guys!


----------



## OctavianH (Apr 12, 2021)

Just received a new pair of Foton 6H8C from here. Fast shipping and all seems fine. Now I see 0 pieces available, but from time to time he restocks.





And the plate, as expected.





I've done also measurements and the internal triodes are quite decently matched.





PS. My photos are not as good as I want to, just changed my phone and I need to make a little bit of research on the 100 unuseful settings of my camera. Yep, new technology beats me, after all I remained in the 70s with the music and amplifiers. LOL


----------



## triod750

OctavianH said:


> I never understood why these guys are putting those papers on them. But they look quite nice.


It's a mark of paid tax.


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## OctavianH (Apr 16, 2021)

*To 6SL7 or not to 6SL7?* This is the question. I do not have any, I am not sure if it makes sense to go on this path. 

Later edit:
A pair of nice Mullard ECC31 appeared at Langrex. So many tubes, so little time and Friday Beerday is coming.


----------



## hpamdr

OctavianH said:


> *To 6SL7 or not to 6SL7?* This is the question. I do not have any, I am not sure if it makes sense to go on this path.


It is high mu very low bias (near 0.5V and under 3.5mA for 180V), i only have 12V version Fivre and TungSol.
I think Tomas (@SonicTrance ) tested for DL 6SL7 as he gave bias point and can tell if sound much better than phillips SE 12ax7.


OctavianH said:


> Later edit:
> A pair of nice Mullard ECC31 appeared at Langrex. So many tubes, so little time and Friday Beerday is coming.


You only need a single tube internally balanced with adapter or ECC32  The good with Langrex is that you can order directly and ask for tube measure before buying and return if it does not fit requirement ! _( the price is too not excessive to buy serenity )_


----------



## OctavianH

Yes, Tomas said -0.765V for 3mA @ 180V.

Honestly I am not thinking to buy, but looking is for free. Let's hope I will remain at looking.


----------



## SonicTrance

OctavianH said:


> Yes, Tomas said -0.765V for 3mA @ 180V.
> 
> Honestly I am not thinking to buy, but looking is for free. Let's hope I will remain at looking.


The 6SL7 is a very linear tube and it sounds great. Can also been found for cheap. I use the Russian 6H9C and it's a very good tube.
It's a high gain tube so you'll have less play with the volume knob. Good for driving insensitive headphones in Eternity as the gain is higher than 6SN7.


----------



## hpamdr

Using 7N7 to 6SN7 adapter, you can use 7F7 tubes also easy to get from US army stocks and cheap.
Not so high gain tube (38 vs 70), i also like 6BQ7A _Miniwatt _wich are in general well balanced (All european tubes are made by Philips)


----------



## OctavianH

I like a lot the 7N7 even if I have only one pair. I think 6F8G and 7N7 are superior to 6SN7 and cheaper. Now I will have the chance to discover 6J5 and 6N7 but the 6SL7 and also the 7F7 sound very interesting. It never ends.

And yes, Friday Beerday with BIOS Flashback guys. I bricked my motherboard today so I had to fix it.






I'll never buy Ryzen and MSI motherboards again, but now I have to live with this one. Quite stable, if you do not touch it.
But today I wanted to move a PCIex card from one slot to another and...


----------



## OctavianH

@SonicTrance Given the power of the Friday Beerday I will ask you a very funny question, I hope you don't mind: The nickname you use on the forum has something to do with the Trance genre? Or it is just about Sonic Nirvana. I have to admit Trance is not my stuff, but I sleep quite good on it, for me it seems it repeats infinitely. LOL


----------



## SonicTrance

OctavianH said:


> @SonicTrance Given the power of the Friday Beerday I will ask you a very funny question, I hope you don't mind: The nickname you use on the forum has something to do with the Trance genre? Or it is just about Sonic Nirvana. I have to admit Trance is not my stuff, but I sleep quite good on it, for me it seems it repeats infinitely. LOL


I don't mind!  

It's a bit of both actually. Sonic Nirvana and Trance music. I do listen to trance, especially at the gym!  I listen to everything from trance to ballads basically!


----------



## OctavianH

Thanks for answer, I have to admit I thought about asking this since I first wrote you if you can build me an amplifier for KT66.

My experience with Trance is a little bit funny, so even if it is offtopic I thought to share it. Many years ago I had to work several months in Sofia, Bulgaria. During those times, because I was not quite knowing better places to go out there, I went several times out in a place called Buddha Bar, central, a garden with music and cocktails. Me, a beer drinker, never expert on what cocktails to order, was all the time receiving many "manly" glasses coloured in pink, orange, green and so on. That's life, you close your eyes and drink them. One evening I went there with a colleague of mine and after several hours of listening to the same song I asked him "Hey, what kind of music is this, this song has 3 hours?". He told me it is impossible not to know this, it is some famous DJ Armin somehow and he has 700 albums. At that moment I almost dropped the glass on the floor "Wow, 700 albums, that's impossible.". In that very moment I was thinking that Judas Priest had around 15 albums, Saxon the same or any other classic rock band which has been active for over 30 years. Later he told me "But this DJ records every party he goes by, mixes something and just makes it available". I said "Ok, not my stuff, I do not even hear instruments". And that was the last time I heard trance. But after 2-3 glasses of Mojito I am not sure if the Mojito or Trance helped me to sleep perfectly. If Trance is the reason I have to find one of those 700 albums to try here in my insomia nights. LOL


----------



## OctavianH (Apr 17, 2021)

Quite enjoyed the latest EP of Left Hand Solution. This cover version of Dolly Parton's "Jolene" was quite a surprise. A kind of dark version.



Another outstanding cover I will never forget is Paradise Lost's cover of "Xavier" from Dead Can Dance.



I never liked cover songs, always thought they are just lack of creativity. But what Paradise Lost made on this one is outstanding, incredible. I am a big fan of Dead Can Dance and also the solo projects of Brendan Perry and Lisa Gerrard.

I think I'll extend my already chosen playlist of Eternity's evaluation with some "extra" tracks.


----------



## hpamdr

OctavianH said:


> Quite enjoyed the latest EP of Left Hand Solution. This cover version of Dolly Parton's "Jolene" was quite a surprise. A kind of dark version.
> 
> 
> 
> ...



I'm also a big fan of DCD and was listening a lot  of 4AD production long long  time ago.


----------



## OctavianH

hpamdr said:


> I'm also a big fan of DCD and was listening a lot  of 4AD production long long  time ago.



Besides what they released together, both had some interesting collaborations and solo albums. From Brendan Perry I like a lot Ark from 2010.


----------



## UntilThen

OctavianH said:


> *To 6SL7 or not to 6SL7?* This is the question. I do not have any, I am not sure if it makes sense to go on this path.


6SL7 and 6SN7 are Odyssey drivers. I haven't bought any 6SL7 yet but my supplier say he has lots of good ones. Will also be using 12au7, 12at7 and 12ax7. In addition to EL11 which have it's own sockets !


----------



## triod750

Is 12AX7 really a good choice as driver, with that high gain (100)? It is usually used in phone stages for raising the low signals you have from the cartridge. If I have the 12Ax7 active in my preamp when playing CD, the sound becomes kind of coloured in a less good way.

Just asking 'cause I don't know the answer.


----------



## UntilThen

Don't know. Guess I'll find out when Odyssey comes. 12ax7 is not my only driver anyway. The choice is there. I'm more looking at 6SL7 and EL11.


----------



## SonicTrance

triod750 said:


> Is 12AX7 really a good choice as driver, with that high gain (100)? It is usually used in phone stages for raising the low signals you have from the cartridge. If I have the 12Ax7 active in my preamp when playing CD, the sound becomes kind of coloured in a less good way.
> 
> Just asking 'cause I don't know the answer.


I use high mµ input tubes all the time. Internal layout becomes very important if you want the amp noise free (which we want!). Tubes like 12AX7 and 6AV6 (like I normally use) is great for voltage amplification if implemented right. If you want to *drive *something with it, like an output tube grid, they are a little wimpy as the anode current is so low. In my regular amps I use CCS loaded MOSFET grid drivers between the input and output tubes. In UT's Odyssey it's a different story and the input tube is actually a *driver *tube. Technically the EL11's will be the best choice for Matt when selecting driver tube (his amp will have both EL11 and 6SL7/6SN7 sockets). Now, technically better doesn't always mean sonically better to your ears!


----------



## UntilThen (Apr 18, 2021)

Odyssey could be the only amp with a dedicated EL11 sockets. Glad you think it's the best choice technically. Now I'm exploring getting adapters to use EL3N or EL33 in those sockets. Will be a challenge for @Deyan .

Or how about adapters for C3g into EL11 sockets.  I've just given myself heaps of options.


----------



## hpamdr

UntilThen said:


> Odyssey could be the only amp with a dedicated EL11 sockets. Glad you think it's the best choice technically. Now I'm exploring getting adapters to use EL3N or EL33 in those sockets. Will be a challenge for @Deyan .
> 
> Or how about adapters for C3g into EL11 sockets.  I've just given myself heaps of options.


The challenge with el11 socket is that it is not easy to get nude base. But you can find defective /unused tubes and then get the base by de-soldering from the pin using flux and pump.. To my experience EL3N are not better sounding than EL11, more prone to noise and very close spec. In odyssey you will have pure driver so medium mu tube 15~30 able to produce current should be the most effective. 

@SonicTrance will give you more hint.


----------



## UntilThen

hpamdr said:


> The challenge with el11 socket is that it is not easy to get nude base. But you can find defective /unused tubes and then get the base by de-soldering from the pin using flux and pump.. To my experience EL3N are not better sounding than EL11, more prone to noise and very close spec. In odyssey you will have pure driver so medium mu tube 15~30 able to produce current should be the most effective.
> 
> @SonicTrance will give you more hint.


Oh I know and much prefer EL11 over EL3N. I've use both sufficiently a lot in Elise, Euforia and GOTL. Just a thought on expanding the driver range that's all. However that will go against what I started out to do. Keep Odyssey simple.

It's also the reason why I've bought 7 NOS pairs of EL11 .... so I have enough to last me 2 life time. Maybe 3.


----------



## OctavianH

So, it began.


----------



## OctavianH

Something interesting for this thread, regarding tube rolling, biases and stuff I do not want to stress the original thread with. It seems what we measure (in my case with DuoVac) is not exactly what we will find when using the tube in the amplifier. For example, this pair of GEC L63 measured around -6.8V for 4mA @ 180V:





When inserted in Eternity it needs around -6.2V for the same 4mA. This means a possible formula for me would be "VgridEternity = VgridDuoVac+0.4V)"
On outputs it seems the reversed way. This pair of GEC KT66 measured on DuoVac -21V for 20mA @ 200V (left stronger one):





When inserted in Eternity I have around 20mA for -21.4V. So here it would be "VgridEternity = VgridDuoVac-0.4V)".
I am not sure about these but I'll keep an eye on them.

Other interesting thing is that after 10-15 minutes when the tubes are properly heated, the current decreases a little bit. When you start the amplifier, tubes start to raise current up to 4mA and 20mA perfectly biased by me. After 15 minutes of usage the current drops a bit around 3.9mA and 19mA.





Of course, not importat but I thought to share these as my impressions while rolling.


----------



## triod750

You get to know things us plug-and-play fools don't have a clue about .


----------



## OctavianH

triod750 said:


> You get to know things us plug-and-play fools don't have a clue about .



I am also a plug and play person, but I am lucky to benefit from the endless patience of Tomas which is always helping me to succeed. 

Anyway, what many including me waited, KT88 on Eternity! The grid bias is, strangely, similay with my GEC KT66 (great stuff, these work on the fixed bias LOL, never thought)





The Psvane CV181T2, one of my favourite 6SN7, goes to -6.5V.





And what is quite nice, the sound si similar with Elise, more neutral than KT66, bass is punching harder. I recognize the signature, and since I am able to tell this, it means Eternity is receptive to tube rolling and changes, up to a point, the signature. Not as much as Elise, and it seems more on outputs than inputs. But again, big grain of salt.
We will talk about this much more in the future.


----------



## hpamdr

This is great for the tube rolling squad to have sonic change with different tube set. Like in Elise KT88 is a bassy tube with strong kick. I'm really waiting mine to test EL39, GU50 ... ECC32, EL11,fdd20....


----------



## OctavianH

hpamdr said:


> This is great for the tube rolling squad to have sonic change with different tube set. Like in Elise KT88 is a bassy tube with strong kick. I'm really waiting mine to test EL39, GU50 ... ECC32, EL11,fdd20....



Exactly, KT88 is more neutral (not so sweet mids as KT66) but with strong bass, very punchy and defined. Since Eternity is warmer than Elise, a good pair for them is Psvane CV181T2 which are incredible detailed. I like this, since on Elise I wanted more bass and was using Foton 6H8C. Here Foton 6H8C was too warm for KT66 and I think it will be the same for KT88. But this combination is a very nice one.


----------



## OctavianH (Apr 21, 2021)

Ok, biases for 6N7G were for me -3.3V and for 6L6GAY were -18.4V.





I started to write my biases measured directly on the amplifier. Might not be perfect but can be a starting point for others.





As a combo I do not like this, thin sound without enough power, but I just wanted to measure the biases.

Later edit: 6N7G in 6J5 slots with triodes in parallel. Don't take that bias for the double triode slot.


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## OctavianH (Apr 21, 2021)

Ok, time for 6V6 and old GEC L63 grey glass. The 6V6 went about -14.5V and the L63 older type to -6V.





This sounds very good. Let's hope it is the merit of 6V6 because I have a lot.


----------



## UntilThen

Some very lovely options you have there. Great tubes.


----------



## hpamdr

OctavianH said:


> Ok, time for 6V6 and old GEC L63 grey glass. The 6V6 went about -14.5V and the L63 older type to -6V.
> 
> 
> 
> This sounds very good. Let's hope it is the merit of 6V6 because I have a lot.


I have several matched pairs of russian 6n6c equivalent of 6V6 (not as nice) but sound great. 
I'm also curious about how sound small tube like ECC83 or ECC88 in input socket ?


----------



## OctavianH (Apr 21, 2021)

Ok, enough tube rolling for today. I got and idea about what bias I have to set for several types. My measurements revealed this and the surprise of my KT88 biasing at the same value like KT66 remains. I would be curious to know in the future other Eternity users what bias will find for KT88. For me this is very comfortable, since I can roll now several nice types without changing the bias. At the moment I set the tube rolling switches to OFF, I went on the fixed bias of -6.2V input and -21.4V output and just put my KT88 and the L63 clear glass to burn in.





Why KT66 and KT88 work at -21.4V? Hell knows, KT88 has to go around -22V or -23V and I doubt these were so heavily used or something. I have a pair of GE 6550A which measured around -25V. We will see, maybe others will come and test more KT88 in the future.


----------



## OctavianH

hpamdr said:


> I have several matched pairs of russian 6n6c equivalent of 6V6 (not as nice) but sound great.
> I'm also curious about how sound small tube like ECC83 or ECC88 in input socket ?



I have no idea and I have no ECC83 or ECC88. But 6V6 were great. I would say close to KT66 and at the price they can be bought, they might be a steal. I remember I found 6V6G around 25EUR/piece. Not bad, if you look about KT66.


----------



## SonicTrance

Love the detailed documentation @OctavianH keep up the good work!


----------



## hpamdr

OctavianH said:


> Ok, enough tube rolling for today. I got and idea about what bias I have to set for several types. My measurements revealed this and the surprise of my KT88 biasing at the same value like KT66 remains. I would be curious to know in the future other Eternity users what bias will find for KT88. For me this is very comfortable, since I can roll now several nice types without changing the bias. At the moment I set the tube rolling switches to OFF, I went on the fixed bias of -6.2V input and -21.4V output and just put my KT88 and the L63 clear glass to burn in.
> .....
> 
> Why KT66 and KT88 work at -21.4V? Hell knows, KT88 has to go around -22V or -23V and I doubt these were so heavily used or something. I have a pair of GE 6550A which measured around -25V. We will see, maybe others will come and test more KT88 in the future.


Hi @OctavianH about bias, I think that some differences are due the gyrator stabilization and tube changing due to heating. 

_-- If you like a bit of Maths--
Ohm low is :* U=RI *(in our case R is 470)_

The measured 200V is not exactly what is constantly supplied to the tube. @SonicTrance Tomas explained the voltage drop balance from firm 210V and with 470R resistor to do the drop in accordance to Ia. But as a retro reaction Ia is linked to Va (also Vg and filament heat stabilization) following Tube curves. 
On the 7-14V range to have gyrator happy we have a load in the 470R resistor from 14.89 to 29.79mA for a resulting 196 - 203 Va. The medium value is 10.5V drop so 22.34mA for 199.5V 
--
I do not have how works input design so cannot do "calculation/guess" !

During Bias we only change Vg, Gyrator and tube do the remaining.... The goal is to listen music at this point, the measure is to get a good idea of tube values and be able to repair tube set in the proper usage range.


----------



## OctavianH

For sure that's the electrical explanation, from user perspective it happens what I described.

There's something fishy with my Psvane KT88T2. As I said yesterday KT88 should bias at a bigger negative voltage.






According to the GEC KT88 datasheed the value is -25V. This is similar to what I  measured for 6550A (KT88 equivalent) and KT150. I think also KT120 should be the same.


----------



## SonicTrance

Doesn't psvane have a datasheet for KT88? You should look there.


----------



## OctavianH

SonicTrance said:


> Doesn't psvane have a datasheet for KT88? You should look there.



Maybe it has but I was not able to find it. I am still searching. Soundwise they sound exceptional. According to my measuremens, several new production KT88 bias like KT66.
I have 2 pairs, one Psvane and one Ayon (most probably Shuguang) and both measured around -22V. There were not bought new by me, but since they were good deals I took them. If I put these at -25V according to the specs I don't think they'll reach 15mA.


----------



## hpamdr

OctavianH said:


> Maybe it has but I was not able to find it. I am still searching. Soundwise they sound exceptional. According to my measuremens, several new production KT88 bias like KT66.
> I have 2 pairs, one Psvane and one Ayon (most probably Shuguang) and both measured around -22V. There were not bought new by me, but since they were good deals I took them. If I put these at -25V according to the specs I don't think they'll reach 15mA.


Hi Octavian,
I have a pair of GL KT88 Russian Made reisue and both measure around  -26.0V Vg 200V Va -20mA Ia. (It needs 15minutes  to have measure stabilized on these tubes continiously heating them)
Also what i was told by a friend is that new production of KTxxx does not have exact same curve than old production. Spec are very close on higher Anode voltage >400V than the one we use.


----------



## OctavianH (Apr 22, 2021)

hpamdr said:


> Hi Octavian,
> I have a pair of GL KT88 Russian Made reisue and both measure around  -26.0V Vg 200V Va -20mA Ia. (It needs 15minutes  to have measure stabilized on these tubes continiously heating them)
> Also what i was told by a friend is that new production of KTxxx does not have exact same curve than old production. Spec are very close on higher Anode voltage >400V than the one we use.


Many thanks for this. Exactly what I was expecting. Well, in my case I have 2 pairs of KT88 biasing at -22V and I can use my fixed output bias for them and KT66.

I gave today another chance to 6L6 which sounded not quite well yesterday. I tried them with warmer drivers (GEC L63) and also with more neutral ones (Fivre 6N7G) and the sound is thin, lifeless. So 6L6 and variants will not be on my priority list anymore. However, 6V6 sounds very good for my ears with 6J5. I will roll several pairs of 6V6 just to see how much of a difference I can hear. Strange about 6L6, I was hoping to have them close to KT66 or KT88.

6V6 on Eternity:





GEC KT66 are warm, very rich in tone especially in the mid frequencies area. I feel that GEC L63 are somehow similar. Combined might be sometimes too much. I went on the KT88 path and reduced the mid assault but added that strong bass and sub bass. It was fine, but again on some specific albums too much. 6V6 are still in the area of KT66 but somehow "weaker" if I might say, the reduce a little bit the richness of KT66 and might be relaxing on some cases. The kings remain KT66 and KT88, looser is for sure for me now the 6L6 but 6V6 is a pleasant and nice surprise. Of course, things might change while rolling drivers but at the moment I want to keep more these L63 I quite like. For these L63 the sound would be for me creamy, rich, warm and detailed. A very nice tone, an incredible tube for around 40EUR/piece. A must have in every collection.


----------



## hpamdr

For me EL32 have also a very nice sweet tone for romantic, chamber music and where  few voices are in front (_not sure that it is your kind of music you like_).
If you have the adapter and want anyway to give a chace to grid cap  
Will you plan EL11 or EL3N as driver ?


----------



## OctavianH

hpamdr said:


> For me EL32 have also a very nice sweet tone for romantic, chamber music and where  few voices are in front (_not sure that it is your kind of music you like_).
> If you have the adapter and want anyway to give a chace to grid cap
> Will you plan EL11 or EL3N as driver ?



I liked EL32 as drivers for 6AS7 in Elise to bring some nice tone to voices. However here I can put them only as output. I plan to do this sometimes, but I am still in the mood of "no adapter when I have so much to try". I have EL32 -> 6V6 adapters, for EL3N I have that monstruous chinese double one -> 6SN7. For EL11 I do not have to 6J5. So What I could try is the EL3N in double adapter. We will see, no prio for me.


----------



## UntilThen

Brimar 6L6GA black glass is very good but I can’t use in Odyssey. I let my friend buy it instead and he’s smiling every night now.


----------



## hpamdr

Take your time Octavian and do not get stucked to first switch impression. 
For me, what is difficult with tube rolling is that it takes time to get accomodated to a combo and only the most colored one can have quick like / dislike.

Does the T1 is still very musical with Eternity ?


----------



## OctavianH (Apr 22, 2021)

hpamdr said:


> Does the T1 is still very musical with Eternity ?



I have not tried T1.2 yet. For me the quantity of bass is quite at the limit with Verite. I will try it later and of course I will spend time on listening, now I just check several pairs to see how they sound as a first impressions. Then I'll focus on the ones I like more.

*Later Edit:* @hpamdr Just tried T1.2 with Forza AudioWorks Noir Hybrid cable with Eternity, with Sylvania 6V6GT/G and GEC L63 (a combo more neutral and airy than with KT66 or KT88) and they sound very good, nice and as I knew them from Elise. Much more bass compared to Verite, same tone as I always knew them. For rock they sound good, but Verite is better in some areas being a little bit more aggressive. For your kind of music I guess they are very musical and you will like them.





From 300Ohm->600Ohm I had to increase the volume, on low gain setting, from 12AM -> 2PM. So around 40% more available on the volume knob. I switched to High Gain and to have the same volume I went back to 12AM. I think I hear a little bit more warmness on High Gain compared to Low Gain, but maybe I am wrong.


----------



## OctavianH

A small discussion about temps:





The amplifier is very silent, the case does not exceed around 30C (ok, in the picture we have 31.5C) in a room temperature around 23C. 
Tubes as seen, KT66 around 80C, L63 around 50C, 6SN7 around 60C. Similar values with Elise.


----------



## hpamdr

So let say that is is a cool amp  (did you measure also on the back near the cooling holes ? )


----------



## OctavianH

hpamdr said:


> So let say that is is a cool amp  (did you measure also on the back near the cooling holes ? )



Yes, same around 30C. It is cool.


----------



## hpamdr

OctavianH said:


> From 300Ohm->600Ohm I had to increase the volume, on low gain setting, from 12AM -> 2PM. So around 40% more available on the volume knob. I switched to High Gain and to have the same volume I went back to 12AM. I think I hear a little bit more warmness on High Gain compared to Low Gain, but maybe I am wrong.


Tomas @SonicTrance could better answer. 

Octavian, i think that is is not like for SS amp where High/Low are used for gain stage but rather High/Low Z are different tap on the output transformer so from 0-100 Low-Z is the best 100-600 High-Z should be the best. If your 300 Ohm is very sensitive, you can prefer low Z position specialy if you have High amplificcation factor tube.


----------



## OctavianH (Apr 23, 2021)

Friday Beerday guys!






I've started with some decent romantic music, how a weekend should start.


----------



## OctavianH

Nighty night!


----------



## hpamdr

OctavianH said:


> Nighty night!


Those meter are really looking nice with orange/yellow light the pictures are great _(specially in dark room) _! 
I really like the analog/old fashioned touch of it, if i have to put it in my main system as pre-amplifier or speaker amplifier i would love to have it.

_// @OctavianH , do you drive your adam A5X directly from TT or through Elise or Eternity ?_


----------



## OctavianH

hpamdr said:


> _// @OctavianH , do you drive your adam A5X directly from TT or through Elise or Eternity ?_



No, I use TT2 only for Eternity. The speakers, which are quite decent according to my ears (well, I am a headphone guy, just use them for gaming), are connected to another DAC via USB: audio-gd NFB11.32.





Please ignore the dust and the box near, that's a mini PC I use for other "experiments". So I use this one for speakers, and TT2 only for Eternity, TT2 has inputs USB from JCAT Femto and Toslink from CXC CD transport.


----------



## OctavianH

Today I will focus on inputs.













Of course, it is too early to say anything, I want to wait until the amplifier has at least 50 hours. The only thing I will say is that the influence of the inputs in the overall signature is it smaller than on Elise. There are differences, but not so big as I knew them. This is what I expected, output rolling is more important in Eternity.


----------



## SonicTrance

OctavianH said:


> Today I will focus on inputs.
> 
> 
> 
> ...


Great! I see you're nailing the bias points for the different tubes! 👍🙂


----------



## OctavianH

SonicTrance said:


> Great! I see you're nailing the bias points for the different tubes! 👍🙂



Yes, I start to get used to roll and I am not so stressed about forgetting something. Great that you made the multiturn trimers increase the current clockwise, exactly in the same direction as the needle of the mA meter goes, so I can easily remember which direction to rotate. Another + on usability.

What I am doing now is to roll several types just as a generic tour to get an idea what signature I obtain. No critical listening, I am not good at that either, I just roll to add or remove something. A kind of cooking, you put this, you put that, and the taste adjustes. It is also the first time I put inputs with different bias on the amp. Before I was just putting equivalents so input switch did not matter. Now, it matters because if I put it to double triode, with -3.2V for 6N7G I think I'll blow the input stage. Brrr.


----------



## SonicTrance

OctavianH said:


> Great that you made the multiturn trimers increase the current clockwise, exactly in the same direction as the needle of the mA meter goes, so I can easily remember which direction to rotate. Another + on usability.


Thanks! 
I thought it'd make most sense to increase the current while turning clockwise!



OctavianH said:


> Now, it matters because if I put it to double triode, with -3.2V for 6N7G I think I'll blow the input stage. Brrr.


Be careful and all shall be well!


----------



## OctavianH

SonicTrance said:


> Thanks!
> I thought it'd make most sense to increase the current while turning clockwise!



Yes, it is very logic and easy for the brain. You look on the meter and see that you have to move the needle right, you turn right and so on. Good decision.


----------



## hpamdr

OctavianH said:


> Yes, it is very logic and easy for the brain. You look on the meter and see that you have to move the needle right, you turn right and so on. Good decision.


You could make a diagram/list for tube rolling like:
Verify the amp is off. (Turn off wait 5min)
Turn volume to zero.
Unplug headphone.
Remove tubes to roll.
Turn on
Set bias to matching Vg 
Use DMM on Vdc red/black. (lower bias to keep small margin for fine tune)
Turn off. 
Wait 5 minutes.
Plug new tubes.
Plug headphone or load.
Turn on.
Wait 5 minutes. (Keep eyes on metter both sides to not go over limits)
Fine tune. (For some Output tube you should wait more to have it well excited)
Fine tune to have medium value L/R on target 4/20
Select output an start to listen set Volume to wanted level.
Enjoy
Print it and put it next to tube drawer.


----------



## OctavianH (Apr 25, 2021)

Yes, it is a good procedure. But I do things in the following way:
- I always turn to 0 the volume when turning off and always rise it from 0 only when the mA meters reached the 4/20mA (or close to it, but needles reached final destination)
- I never remove the headphone, I think in time the 6.3mm jack will loose its grip and as far as I understood from Tomas is not needed
- I splitted all the switches of the amp in 2 categories, first one switches which can be used during operation and second one switches which need before a turn off ("Impedance switch" and "VU meters off" is in the first category, the rest of them in the second)
- I always wait 5 minutes without touching anything (not removing tubes) after each Turn Off.

These 4 rules are helping me a lot. Please correct me if I am doing something wrong, I guess except removing headphone it is the same as you.


----------



## SonicTrance

OctavianH said:


> - I splitted all the switches of the amp in 2 categories, first one switches which can be used during operation and second one switches which need before a turn off ("Impedance switch" and "VU meters off" is in the first category, the rest of them in the second)


You can also switch the meter L/R switch while amp is ON. Just make sure to let the amp settle for a couple minutes after ONE switch. Don't toggle both input and output switches at once! The safest way is to just toggle these with amp OFF! I don't recommend beer drinking while switching them, lol!

Anyway, if you do toggle the meter switches with amp ON, please do remove the headphones as there will be a "pop" when switching.


----------



## OctavianH

SonicTrance said:


> Anyway, if you do toggle the meter switches with amp ON, please do remove the headphones as there will be a "pop" when switching.



This is the reason I included the meter L/R switches in the second category, to avoid removing the headphone. But since I was able to measure all my tubes, I marked in my notes the strongest one (strongest = the one which has the highest current from the pair at the same grid bias). I always put on left socket the strong tube from the pair. I always keep the meter switch to L. In this way I ensure that I monitor the highest current from the pair when the amplifier is starting. If I have to switch off, I'll set the switch to R at next startup just to see how much lower the other tube goes. I always dwell 10% lower the required current just to be safe. Until now this methodology worked.

And yeap, tube rolling ON = beer rolling OFF. Or was it the other way? Hmm. LOL.


----------



## SonicTrance

OctavianH said:


> This is the reason I included the meter L/R switches in the second category, to avoid removing the headphone. But since I was able to measure all my tubes, I marked in my notes the strongest one (strongest = the one which has the highest current from the pair at the same grid bias). I always put on left socket the strong tube from the pair. I always keep the meter switch to L. In this way I ensure that I monitor the highest current from the pair when the amplifier is starting. If I have to switch off, I'll set the switch to R at next startup just to see how much lower the other tube goes. I always dwell 10% lower the required current just to be safe. Until now this methodology worked.
> 
> And yeap, tube rolling ON = beer rolling OFF. Or was it the other way? Hmm. LOL.


Excellent! 👍🙂


----------



## OctavianH

And the reason I wanted to have an amplifier called Eternity:





I think this album breaks the barriers of its genre, it is much more than this and deserves to have an amplifier named after it, at least for me. Highly recommended for everyone.


----------



## OctavianH

Temperature increased a few degrees with KT88, amplifier runs already for 5 hours. We have around 37-38C on the transformer cover and also on the vent holes from behind. This is impressive, cooler than my DAC or upscaler. LOL. I will measure with KT150 just to see. Those I think have around 2A.


----------



## OctavianH

Interesting thread related to KT88. I read it to find out more about Tesla KT88, the ones here which according to the testing papers are dated 2004. Some remarks about the production with blue logo:



> There was from 2001--2003 some retro production of the TESLA KT88, with the blue logo. I had three charges of them, and the overall failure rate was 10% within the first six months use. From this the statistic calculations say you have 35% chances on ONE bad tube in a QUAD. As you can understand, this made this business not very pleasant to do.



Not very nice to read, since Langrex asks 450 EUR / pair. LOL


----------



## hpamdr

OctavianH said:


> Interesting thread related to KT88. I read it to find out more about Tesla KT88, the ones here which according to the testing papers are dated 2004. Some remarks about the production with blue logo:
> 
> 
> 
> Not very nice to read, since Langrex asks 450 EUR / pair. LOL


Dis you tested KT88 with 7N7 ?
Sylvania made most of the 7N7 tubes and this is a quite neutral driver not as warm as 6N7G or some 6SN7/VT231 this could be a good match with your KT88.

About KT88 new productions are IMO not so bad ! I like the GL reisues, they comes with a waranty and can be matched by pair or quad from seller or direclty at production.


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## OctavianH (Apr 26, 2021)

hpamdr said:


> Dis you tested KT88 with 7N7 ?
> Sylvania made most of the 7N7 tubes and this is a quite neutral driver not as warm as 6N7G or some 6SN7/VT231 this could be a good match with your KT88.
> 
> About KT88 new productions are IMO not so bad ! I like the GL reisues, they comes with a waranty and can be matched by pair or quad from seller or direclty at production.


Yes, I tried 7N7 with KT88 and it is a good pairing. However, now I try KT88 with 6N7G and I do not find them warm. A good combo also this one.
I was not quite impressed about VT-231 on Eternity, but the overall influence of the inputs is smaller, maybe this is why I do not hear big differences.
I was expecting to be blown by the bass of Ken-Rad VT-231, one of my warmest drivers on Elise, but on Eternity it sounded close to other 6SN7, with less detail and a bit more forgiving, but that's it. Ok, maybe an idea warmer but not what I was used to hear. This amp is for output rolling, and until now KT66 and KT88 rule.

Later edit: I found warmer the GEC L63 compared to Fivre 6N7G. But as I said, not huge differences, more nuances or tone changes (these are more creamy, somehow richer tone than the others which were more towards clarity and neutral sounding). Here if you want to change something you swtich outputs. Both KT66 and KT88 sound killer on this amplifier, you do not need more, in my opinion.





Which leads me to a thing I was thinking about in the last days, how I would see a budget version of Eternity. Only exactly what you need to have the best of it, at an umbeatable price. And my answer to this would be, especially if you have other tube amplifiers in the collection:

- Eternity in smaller chassis
- input switch to select single/double triode (or speaker outputs if you need that instead)
- impedance switch
- teflon sockets (they make a difference, makes sense)
- fixed bias on input for 6SN7/6J5/7N7
- output bias switch for KT66/KT88 (maybe Vgrid=-21V and Vgrid=-25V), so you can use KT66 on one position and KT88/6550A/KT120/KT150 on the other

And that's it. Such an amplifier at a good price would be a giant killer. Honestly. Of course, you can have variable bias, and try 200 types of tubes and so on, but from what I heard until now this is the core you need to be happy. Now let's see how @hpamdr GU50 will sound because we might kill the giant killer with another giant killer.


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## hpamdr

If you like KT66, you should try a pair of 6p3s-e or 1540


OctavianH said:


> Now let's see how @hpamdr GU50 will sound because we might kill the giant killer with another giant killer.


I've listened some speaker amp with 4xGU50 running at higher voltage around 400V/80mA. I was very impressed by the dynamic and the overall neutrality with old Focal Utopia speaker.
I did not used any external heater on F.A. amp so i do not know if it will sound great. I'm really expecting for first Tomas impression......


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## OctavianH (Apr 27, 2021)

I might try some russian equivalents at a later point in time, at the moment I do not need to. I have so many things to discover with my existing tube collection.
Eternity reached yesterday 50 hours of usage and at this point, after I have done a tour of my most interesting inputs and outputs, I started to focus on combos, combinations with synergy which provide me the best experience, and at the moment I have chosen 3. Of course, I will need 60-80 hours on each because the inputs are all NOS and not used before, so everything is preliminary.

The tracks I decided to try are very unusual, even for me:
1. Harakiri for the Sky - I, Pallbearer
2. Orden Ogan - Absolution for our Final Days
3. Random Black Sabbath songs.

The first one I am going to present is the Psvane KT88T2 with GEC L63 brown base clear glass.





This is a combo for fuller sound, everything sounds bold, heavy and full of energy. The bass of KT88 is the best one I had the chance to hear on Eternity. But of course, something good comes at a price, and the price is a more solid state, lifeless presentation, and a narrower soundstage. I have also a feeling that there is a small high frequencies roll-off with this one, but if you want a song to sound heavy, well, here is your recipe.

The second one, which I consider at the moment the best, is the GEC KT66 with GEC L63 grey glass ST shaped.





These inputs were not cheap, they are still for sale at Langrex and honestly, I think they are the best I  have at the moment for Eternity and maybe some of the best I have in the entire collection. Combined with KT66 these provide me what might be an endgame. The sound is warm, liquid but up to a point, voices and keyboards sound lively and the quantity of bass is moderate. The bass in this combo is in the background, the guitar is on the lights of the stage. The soundstage is wider than with KT88. There is a downside here, the bass is not as articulated and punchy as on the KT88, but this might change during burn in. It will not match KT88, but might be better defined.

Besides these 2, I want to give more attention to the Psvane KT88T2 with Fivre 6N7G. This is something interesting, and sits at the moment on position 3.





Since I am not burning in tubes with noise or let the amplifier turned on during night like others might do, I had to find some combinations which provide me enough pleasure during normal listening sessions. Being armed with these 3 sets of very nice and interesting combinations I will embark now in the process of input burn in. After around 60-80 hours with each one I will start again to assess them. Now we had only a preliminary audition, later the contest and in the end the hall of fame.

As you can observe, the 6J5/6N7G were preferred to the 6SN7/7N7/6F8G even if yesterday I tried several of them. The sound with these is cleaner, more detailed and it matches better my KT outputs. We will see where this will go.


----------



## hpamdr

So  I will give a try with same KT66 as Tomas. 
I was reading some article from Fancis Ibre and he claimed that KT66 with good driver can gives a kind of magic specialy in triode mode which is lost with KT77 or KT88. 
But you gain more bass and power with KT88 and more neutral sound with EL34/KT77.


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## OctavianH (Apr 27, 2021)

I am not good at describing what I hear, but I think what you told me matches what I described on KT88 and KT66. I have no EL34 and I tried on Elise a pair of KT77 but on that amp KT77 sounded very warm and forgiving, so different than what you describe. Unfortunately my pair of KT77 is very unbalanced and I obtained strage results while measuring, so at the moment it is banned to be tried on Eternity.





I obtained 20mA at -16V on one of them and -19.2 on the other, trying to find a medium value I went on crazy 28.3mA while the other was only at 12.2mA. So... I will let others try KT77 and I will focus on KT66 and KT88. Might try also KT150 at a later point in time.

Later edit: I might pull the trigger on a cheap pair of RFT EL34.


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## SonicTrance

OctavianH said:


> I obtained 20mA at -16V on one of them and -19.2 on the other, trying to find a medium value I went on crazy 28.3mA while the other was only at 12.2mA. So... I will let others try KT77 and I will focus on KT66 and KT88. Might try also KT150 at a later point in time.


Wow that's terribly unbalanced tubes. I'd say the tube that needs -16Vg to draw 20mA is pretty weak.


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## hpamdr

SonicTrance said:


> Wow that's terribly unbalanced tubes. I'd say the tube that needs -16Vg to draw 20mA is pretty weak.


This is the drawback of measuring or having meter on the amp.... You discover that some good ebay auction are not so good.
I've measured 6 GU50 almost exhausted (bias -14V instead of -30V ), i got 10 tubes for 25$ + 10$ shipping but only 4 were strong.... Too late to complain 

Today i got a pair of Melz 6H9C metal base not too strong but well balanced. I prepare for Eternity to match with Gu50 (Full USSR setup  )  on F.A. with EL39, the tone is very special ! A bit warm, some emphasis on details and really good sounding for voices...



@SonicTrance , Tomas, have you ever used  EF184 as input ?


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## OctavianH

Today I added something new on the playlist. I just found this swedish symphonic metal band:



Well, this is very good for tube burn in, female vocals with keyboards and a lot of electric guitar. Excellent for my KT66 + L63! And the girl is also a professional model, her name is Madeleine! Maybe this is the reason for the band's name? Location of the band is Landskrona, Skåne. Sounds brutal. LOL


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## OctavianH (Apr 27, 2021)

Evening.


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## SonicTrance

hpamdr said:


> @SonicTrance , Tomas, have you ever used EF184 as input ?


I haven't used them at all. So many tubes so little time..



OctavianH said:


> Evening.


Beautiful!


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## UntilThen

It's been quiet here so I'll share what new tubes I just bought for Odyssey. I'm quite complete now for drivers in one transaction because I've got some nice 6SL7 equivalents. Also bought 2 different pairs of KT88. Plus the Genalex Gold Lion KT88 that I already have, that's 3 current production pairs. As Odyssey is biased for KT88, it's fitting that I've a few pairs of KT88. The last elusive pair is the GEC KT88.

GE 5691 - premium 6SL7 with a 10,000 hours estimated life span. 


Tung Sol 6SU7GTY - 6SL7 equivalent.




Brimar 6SL7


Shuguang Black Treasure KT88-Z




Psvane Classic MKii KT88


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## OctavianH

UntilThen said:


> It's been quiet here so I'll share what new tubes I just bought for Odyssey. I'm quite complete now for drivers in one transaction because I've got some nice 6SL7 equivalents. Also bought 2 different pairs of KT88. Plus the Genalex Gold Lion KT88 that I already have, that's 3 current production pairs. As Odyssey is biased for KT88, it's fitting that I've a few pairs of KT88. The last elusive pair is the GEC KT88.



Very nice! Shuguang Black Treasure and Psvane KT88T2 (similar with mine). I am really curious about what you will say about these. I love my Psvanes but read nice things about the Black Treasures.


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## UntilThen

OctavianH said:


> Very nice! Shuguang Black Treasure and Psvane KT88T2 (similar with mine). I am really curious about what you will say about these. I love my Psvanes but read nice things about the Black Treasures.



I bought them off a friend who chose Auris Nirvana over his Bigger Ben. So these tubes (drivers and power tubes) have been slightly burn in with not many hours of usage and sold to me quite cheaply. A good friend indeed.

Things have been just right for me lately. Destiny the 300b amp will be ready for collection on Sat morning. LCD4 arrives on Friday.


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## UntilThen

OctavianH said:


> I might pull the trigger on a cheap pair of RFT EL34.



I've heard it and use it on the Elekit TU-8200 when it was still alive, the sound is tight and leaner than the Philips Miniwatt 6CA7 (EL34). For the price it's worthwhile getting a pair. The Mullard EL34 NOS or Philips Miniwatt 6CA7 is still better.


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## OctavianH (Apr 28, 2021)

I am currently investigating the situation of the EL34. I have to admit I have ignored them until now. From what I see on Ebay and also on different websites, the cheapest NOS are RFT (some rebranded Siemens or other name). The Mullard EL34 is much more expenssive, I've seen also some Valvo, some Tesla or Telefunken, all of them more expenssive. Honestly I have no  idea what to choose or if to choose something. I will continue to read, any advice is welcomed.

Interesting to read is this link.

And a book!

Later edit: Ah, these are cheap, I'll take them. LOL


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## hpamdr

About EL34, You can get sometimes Mullard EL34 or Tesla EL34 rebranded by Haltron or Ultron but as those also rebrand many tube not as good you have to be careful if you want to get the right ones. With the book, you can have a closer look to the construction and get the right tube for the right price. 
The metal base are very expensive and not easy to find as a reallly matched pair unless you know someone changing amplifier with tubes keep the tube, re-sell the amp !
Quality of EL34 vary a lot, it is like comparing GEC 6AS7G brown curved base with 6H5C.
I personally got a pair of Ultron in fact old Tesla Production, i prefer 10 times more EL39 !


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## OctavianH (Apr 28, 2021)

From Tesla EL34 and RFT EL34 what you advise to choose? I've seen some Tesla brown base double halo getter at around 25-50EUR (depending on quality) and RFT EL34 black base single ring getter at around 25-30 EUR if you search a little bit. Mullard EL34 xf* are very expensive, hard to find a matched pair and so on...

Later edit: Mullard metal base:


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## triod750

OctavianH said:


> I am currently investigating the situation of the EL34. I have to admit I have ignored them until now. From what I see on Ebay and also on different websites, the cheapest NOS are RFT (some rebranded Siemens or other name). The Mullard EL34 is much more expenssive, I've seen also some Valvo, some Tesla or Telefunken, all of them more expenssive. Honestly I have no  idea what to choose or if to choose something. I will continue to read, any advice is welcomed.
> 
> Interesting to read is this link.
> 
> ...


It's funny when they translate 'valve' to 'ventil'.


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## OctavianH

triod750 said:


> It's funny when they translate 'valve' to 'ventil'.



Yes, first time I've seen that I was thinking about the wheel of a bike.


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## UntilThen

You buy EL34 for it’s lushness and ‘romantic’ tone. You buy KT88 if you want slam, punch and a hard hitting tone. The contrast cannot be greater here. KT77 falls somewhere in between and KT66 leans more towards EL34. EL12 spez is a EL34 on steroids.

It’s generally agreed that the best EL34 in terms of smoothness and fluidity are the Mullard EL34 (xf2 would be nice) of which the Philips Miniwatt 6CA7 is similar. Even within Philips Miniwatts 6CA7, you have different constructions. Those in the know claim that the double 'O' rings getters are better than the single 'O' ring and that the double 'D getters are the best, aside from the metal base. Telefunkens and other East German brands generally have a different tone - leaner and tighter with better dynamics. Which is better depends on your preference.

When you have an amp like Eternity, you can loose sight of why you got an amp in the first place. That is to find an amp that fits into your system and that synergises with the rest of your gear. Tube amp rolling is part of the fun and the reason we do that is to fine tune our system. However you can get too caught up in this and miss the joy of discovering new songs. Instead you repeat all your favourite songs and marvel how wonderful and slightly different how each song sound with each new tube change. There's no right and wrong here. A person chooses how they use their finance and their time. If tube rolling serves as part of your enjoyment so be it. However from my past experience and from many others, there will come a time when you'll settle on a tube combination, settle back and just enjoy the music. Then you'll look at your pile of tubes sitting in boxes and wonder how you got this point.  and you start to sell them off... and the next buyer repeat the process. It's the circle of life.

Just take care of the tube sockets. They wear out over time with repeated and frequent tube changes. Socket savers help but they just create another unnecessary layer that will not aid SQ.

My advise is to buy a pair of Mullard or Philips EL34 when you have the means and be done with it unless you're UntilThen.   I wouldn't roll 300b tubes though because they are too cheap and tube rolling in them cause migraine and heart palpitations.


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## OctavianH

Wise words. Well, the tone of KT77 was never exactly what I preferred. This romantic and lush presentation is not matching my type of music. But I want to try a pair of EL34 just to see if the tone is the same as expected in Eternity. So I went to a pair of Tesla brown base overlapping double-O getter rebranded Edicron. From what I read the 70-80s Tesla made in Czehoslovakia are quite good, having a better high frequency extension and better dynamics than the Mullard, which of course has other qualities, being more romantic and rich in tone. In my case I guess it was the best choice, if not we will search for others. As you can see I already settled to KT66/KT88, this amplifier was built for KT66 in my case, and tube rolling is ocasionally just for fun. I have not rolled anything for 3 days.


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## UntilThen

GEC KT66 was one of my favourite when I was rolling in Elekit TU-8200. Only piped by the EL12 spez IMO. The Philips Miniwatt 6CA7 is third.

I need to explore KT88 again. Pretty sure I will try KT150 just for the fun of it. EL156 looks tempting. Thereafter I will roll drivers followed by rectifiers.

The combination I am looking forward to is EL11 and EL12 spez.


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## OctavianH

UntilThen said:


> I need to explore KT88 again. Pretty sure I will try KT150 just for the fun of it. EL156 looks tempting. Thereafter I will roll drivers followed by rectifiers.



When the KT* mania started on the F.A. amps I bought new russian production of Tung Sol 7581A, Gold Lions KT66/77/88. From all of these KT66 was my preference but KT77 had a nice tone, warmer, good to use in those amps as driver. Many used KT88 driven by KT77 or 6L6 and considered a very good combination. The reissue of KT88 sounded for me harsh, somehow towards solid state and I renounced on them fast. A similar, but better tube was, for me, 6550A (KT88 equivalent). Now a long time ago I had the chance to buy at a very good price (50EUR/tube) a pair of Psvane KT88T2 (similar to what you have posted yesterday, orange base grey glass) and these sounded incredible to me even on Elise. But from what I remember (cannot compare now, my russian Gold Lions KT88 are sold for many months already) these sound very different from what I knew about KT88, very clean, full and articulated, without that harshness and even that solid state feeling is much attenuated. Even the bias values are strange for me, since these Psvane I have are biasing similar with my KT66 (not sure if a general problem or specific to my pair). I cannot say how these compare to GEC KT88, I never heard them, let's hope I will be lucky enough to find a pair at a good price sometimes.


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## UntilThen (Apr 29, 2021)

Surprise that those power tubes works well as drivers in FA amps. Practically almost all amp builders will not agree with that.

I have only use Gold Lion KT88 in TU- 8200 and Primaluna KT88 in the Primaluna Dialogue Premium HP amp. In both instances, the tone is leaning towards solid state tightness and hard hitting. I need to use this LCD4 with that. Should be very interesting.

Several well known tube amps uses 6SL7 as drivers. Such as Bigger Ben and Mogwai Se. As well as Eddie Current Zana Deus. 6SL7 will also be use as drivers in Odyssey as well as 6SN7. I have 2 good 12au7 and 12at7. Odyssey will be very versatile and will have tremendous power. Even more powerful than my 300b amp.


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## hpamdr (Apr 29, 2021)

UntilThen said:


> Surprise that those power tubes works well as drivers in FA amps. Practically almost all amp builders will not agree with that.
> 
> I have only use Gold Lion KT88 in TU- 8200 and Primaluna KT88 in the Primaluna Dialogue Premium HP amp. In both instances, the tone is leaning towards solid state tightness and hard hitting. I need to use this LCD4 with that. Should be very interesting.
> 
> Several well known tube amps uses 6SL7 as drivers. Such as Bigger Ben and Mogwai Se. As well as Eddie Current Zana Deus. 6SL7 will also be use as drivers in Odyssey as well as 6SN7. I have 2 good 12au7 and 12at7. Odyssey will be very versatile and will have tremendous power. Even more powerful than my 300b amp.


I was in contact with Henryk long time ago about tube adapter.... He gave me some hint on F.A. tolerance he was OK for having EL/KT tube as output but was not ready to promote those in driver position. In fact he finally decided to not promote none of the "Exotic" combination you can find in F.A. thread. The special auto-bias and the capacitor used makes the amp very versatile. Euforia sound good with a lot of tube combination and with many headphone. Even if it is not the best for every combination it is most of the time in good position ! 

I also use 6H9S as driver with EL39 on EuForia, I can say that this is a very special combination that emphasis details and soundstage but still with a warm/romantic overall tone. I plan to also use 12SL7  on Eternity and 12SC7 almost same characteristics as 6SL7 but more powerful and easier to bias   I will personally keep Euforia to play and enjoy with with tube rolling. Eternity will be used to find good combination and enjoy music. Excatly as you said, tube rolling and music listening are not exactly the same hobby.


----------



## OctavianH

This morning I had a surprise when trying the GEC KT66 with one of the tubes I never enjoyed and liked, actually I always considered it one of my worse acquisitions. The Philips 6SN7WGTA:





I tried these on Littledot MK2, at that time with some adapters in the power position (if I remember correctly), then with Elise as drivers. All the time I was considering these dull sounding. Well, today just for fun, since the tube was already in the position, I switched the input from single -> double triode and started the amplifier.
I was prepared to stop it fast and put a "decent" driver but the sound I heard was extremely clean, clear and towards neutral. A lot of micro details, these taming a little bit the KT66 sweetness. I have to admit that I prefer a little bit more of a full bodied sound, but honestly these were a surprise. I wonder how such clean neutral drivers would complement a lush and romantic EL34. I think I have to try this! So, surprise. I know that this tube is not well respected in the community, many consider it, like I was, a dull sounding 6SN7.


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## OctavianH (Apr 29, 2021)

And yes, brutal times, it had to be done. KT150 on Eternity! I've checked the grid bias twice, -25V to be sure.





I've tried to sweeten them a little bit with the GEC L63, still quite dry sounding. A lot of bass, power and good clarity. What to say, I prefer KT88 or KT66, but had to try these.
KT150 on a small headphone only amplifier. Next KT170 when they release them. 

And, to have an idea about the size difference:





The currents started with delay to rise on KT150. The inputs were already at 4mA when the outputs started, slowly, to rise. They got also quite hot, I had to wait a few minutes to be able to remove them.


----------



## OctavianH

Back to my beloved KT66. I think I get more and more addicted to the GEC L63 grey glass. This pairing might be an endgame for me.






On the other hand, I realized that Eternity is more unforgiving than Elise. It is more resolving, wider soundstage, but also makes worse produced records sound harsh in some passages. Of course, there are more micro details and the ones with decent production sound better and with a more natural tone. I have to make some time in the next days for T1.2. I think that warmer and more relaxed headphone might compensate. We will see.


----------



## OctavianH

Friday Beerday! This weekend is dedicated to german beer.


----------



## hpamdr

OctavianH said:


> And yes, brutal times, it had to be done. KT150 on Eternity! I've checked the grid bias twice, -25V to be sure.
> 
> 
> 
> ...


KT150 use almost 2A at 6.3V and like new KT88 have a metal base which is hot really fast !
Removing hot tube is also not the best a


OctavianH said:


> Friday Beerday! This weekend is dedicated to german beer.


No Beer day  
The one i like a lot are the Dunkel and Hefe ... (Weis, Helles are just apetizer


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## OctavianH (Apr 30, 2021)

hpamdr said:


> KT150 use almost 2A at 6.3V and like new KT88 have a metal base which is hot really fast !


You are right it got hot fast and the sound was, for me at least "synthetic". For rock music definitely not a good choice but maybe for some electronic music this might go.


hpamdr said:


> The one i like a lot are the Dunkel and Hefe ... (Weis, Helles are just apetizer


I do not drink a lot of Dunkel because I find it too sweet and I like bitter beers. The only ones which are sweet and I like are the Weizen, the wheat white beers. But it depends, from time to time I try to be original, so I switch from weiss beer to english ale, then to normal helles and so on. I make no discrimination, I drink all beers except the ones with fruits or other ingredients. I am a purist, beer has to be beer. If you want something else you have other drinks to choose. I do not know if you use android, but it might be available also on iOS, there is an app for beer drinkers called Untappd and you can find beers, places to buy beer or you can just scan the barcode of a beer and find rating and information about it. I use it


----------



## hpamdr

I will give a look ! Do you have the same app for tubes


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## OctavianH (Apr 30, 2021)

hpamdr said:


> I will give a look ! Do you have the same app for tubes



Unfortunately not, even if I read somewhere that there is an android version for TDSL (tube datasheet locator). Who knows, maybe I'll make one, I do not think creating an android app is so complex, but anyway, why do we need it? Retro is better. 

@hpamdr This one is better?


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## OctavianH (Apr 30, 2021)

This evening I have decided to return, after some time, to Ronnie James Dio. The reason was that in the morning I heard a cover of "Die Young" made by a young swedish band called Trial on their latest EP called "Sisters of the Moon". Incredible band, I will search for more of their work. So I started with "The Devil You Know" remembering that I saw for the last time Ronnie in 2009 at W:O:A in Germany, a few months before his passing, on tour with Heaven and Hell.



The first thing I have observed, listening for the first time to this album with Eternity, armed with GEC KT66 + GEC L63 grey glass, was how bold and full bodied was the sound. At first I said it is too much, I was used with a more thin presentation. Using Verite Open which are my most neutral headphones, if you can call them like that because they are quite warm compared with ADX5000 or HD800, I was surprised about what I was hearing. But later I start to enjoy more and more this kind of sound I was not used to. After forgetting to analyze or think about, just listening to music, I realized that this kind of signature was reminding me about my childhood when I was listening to tapes. Which one is the right presentation? A thinner and more analytical one or a wider and bolder, yet with the same detail level one? Hard to say and I think this is not the proper way of making assessments. There is no right or wrong presentation, and you should just follow what your ear tells you. The right presentation was in their studio when they recorded but maybe you wil be disappointed about how they sounded that specific time because I am almost sure that was different than what we are hearing with our amps or expecting in our hearts.

Willing to continue in the same direction I have decided to listen to Black Sabbath's Dio's albums "Heaven and Hell" and "Mob Rules".



Eternity sounded quite in the same style as before. We have 30 years between "The Devil You Know" and "Heaven and Hell" but the signature was similar. Warm, bold and analogue.

Why I have you told this story? Because my greatest fear was that Eternity, using all those MOSFETs and gyrators and the new approach on tube design will sound thin, will go towards solid state or will lack the quantity of bass I always enjoyed. The listening session from today proved me that Eternity is by far a thin or solid state sounding amplifier. It can sound very warm, lively and full bodied if the tube combination is wisely chosen. I have to admit that I had my preconceptions that newer technology cannot make 70s music sound better than a classic design and those were wrong. Eternity is warm, full bodied, yet with a very wide soundstage, good micro detail and incredible dynamics. But of course, this comes to a price, it is more unforgiving that other amplifiers I had the chance to try and sometimes I am not sure that the wide soundstage on some specific rock albums is helping or making them sound worse. It might be, of course, a matter of production of those specific records, but in the end this genre was always underground and many of its best offerings were garage recorded and then remastered but never reaching the level of a proper recording.

Another thing I learned today is that I need to renounce on everything I knew about some albums and my expectations of how it should sound and start over, from scratch. This is what I had to do today to embrace the modern Black Sabbath from the Dio era. A few days ago I learned that what I knew about the input tubes is not valid anymore (outputs were closer to my expectation) and today I learned that the signature and overall presentation has to be re-assessed from scratch. No problem, we do this, we rediscover the music, let's hope in a better way.

That's it, I return to my listening sessions, and it's The Sign of the Southern Cross this time.


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## OctavianH

Yesterday I had the chance to visit a small museum in my vicinity. Between several other sections it had a room dedicated to old radios and audio equipment.





Even something for the vinyl enthusiasts:





But what was more interesting for me were 2 panels on the wall with.... guess what guys... TUBES!









And hanging some quite big ones:





Who knows, maybe in 50 years our amps will be present in this room.


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## SonicTrance

OctavianH said:


> Yesterday I had the chance to visit a small museum in my vicinity. Between several other sections it had a room dedicated to old radios and audio equipment.
> 
> 
> 
> ...


Cool! But no GEC KT66's on the wall!


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## OctavianH (May 2, 2021)

SonicTrance said:


> Cool! But no GEC KT66's on the wall!



Indeed, it needs improvement, but I would say let's keep the KT66 in our amps.

By the way today I played a little bit with the Impedance switch and besides the small volume differences, I observed a very slight difference in tone on High Z compared to Low Z. Maybe I am wrong but on High Z the Verite Open sounded a little bit more romantic, maybe with less dynamics than on Low Z. Strange, I would not expect that. I will continue to play with this switch since it can be used during normal listening, without any power off or something, so quite comfortable.


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## OctavianH

Evening. After around 60 hours the GEC L63 grey glass are sounding phenomenal and the synergy with GEC KT66 is incredible.


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## SonicTrance

OctavianH said:


> Evening. After around 60 hours the GEC L63 grey glass are sounding phenomenal and the synergy with GEC KT66 is incredible.


Beautiful! You notice much improvement with burn-in on the L63's?


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## OctavianH (May 3, 2021)

SonicTrance said:


> Beautiful! You notice much improvement with burn-in on the L63's?


In the first hours they sounded more congested and they lacked clarity. Now they become more clean sounding and somehow have a decent distance between instruments. What to say, I never believed that the tube burn in will make a worse sounding combo sound great, but a few number of hours can help an already decent sounding combo to evolve a little bit on the clarity/soundstage area. I knew from the beginning I will like this combination, but now I am just enjoying it more.


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## hpamdr

OctavianH said:


> In the first hours they sounded more congested and they lacked clarity. Now they become more clean sounding and somehow have a decent distance between instruments. What to say, I never believed that the tube burn in will make a worse sounding combo sound great, but a few number of hours can help an already decent sounding combo to evolve a little bit on the clarity/soundstage area. I knew from the beginning I will like this combination, but now I am just enjoying it more.


This is really great that you found within the "pre-configured" bias your good sounding combination !
And for your pleasure it get better and better...  
Tobay i was listening EL34 (Old Tesla dual O getter) as power but to get the best I have chosen EL11 as driver on Euforia. With less juicy driver 6SN7 the sound was for me not as clear and dynamic then with EL11 or 6M6...


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## OctavianH (May 3, 2021)

It is still to early to tell, but for sure this combo will be on my top list. I am not able to use the preconfigured bias, since these L63 grey glass need -5.7V for 4mA. Yes, they seem weaker than the other pair of L63, so I have biased them on the variable input. If on Elise I had 1-2 combos which were sounding decent to mostly of my albums, here one combo seems good for a part of them, but sounds much worse on others. This is why, based on what I listen, I find it more appropriate or not. And I am still having some problems to accomodate with the much wider soundstage on some specific tracks. This might be my problem or maybe VO is not the best pairing.


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## OctavianH (May 4, 2021)

This evening I realized that I prefer specific headphones when using specific tube combinations. A few days ago I was telling you that the GEC L63 brown base clear glass have a very warm and full bodied sound when combined with GEC KT66 or Psvane KT88T2. These inputs make everything sound bolder, somehow narrowing the soundstage and giving you a kind of slow retro sound. I cannot describe it better than comparing it with an over exposed picture from the 60s. But this kind of signature with Verite Open made everything sound somehow dry, lifeless, voices being more in the background. Therefore I fixed it, I tried T1.2 and everything came back to a more romantic and airy sound. Voices are more alive, everything goes back to normal at the cost of a little bit of resolution, but with the more analytical/clean signature of the amplifier this is no big problem. On Elise I had the feeling that T1.2 is too polite and cannot keep the speed of some specific tracks, here I think it adds the small dose of musicality we need on specific tube combos like this one. I always liked contrasts. Warm output with neutral input, more analytical headphone on warm amplifier (Elise with VO and Auteur and other neutral/analytical headphones) and today I tried a more forgiving and relaxed headphone on a more analytical and clean signature, like the one provided by Eternity. I do not think you can obtain a perfect synergy and you will always you reach a compromise. This evening the compromise of small loss in resolution provided a more enjoyable overall sound. And last but not least, the comfort provided by T1.2, at least for me, is much bigger than the one of Verite Open. That headphone is much more heavier. Of course, it has some pros and wins on some other sections.






So yep, T1.2 has good synergy and sounds great with Eternity, I think @hpamdr will enjoy it. One remark, I preferred the High Impedance setting for this one.
I have to admit I would like to try LCD-3 or even LCD-4 on this amplifier, but my wallet does not agree. Even my Forza AudioWorks Noir Hybrid cable works with Audeze. Well, who knows, maybe I'll sell Verite Open and try those LOL


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## hpamdr

OctavianH said:


> This evening I realized that I prefer specific headphones when using specific tube combinations. A few days ago I was telling you that the GEC L63 brown base clear glass have a very warm and full bodied sound when combined with GEC KT66 or Psvane KT88T2. These inputs make everything sound bolder, somehow narrowing the soundstage and giving you a kind of slow retro sound. But this kind of signature with Verite Open made everything sound somehow dry, lifeless, voices being more in the background. Therefore I fixed it, I tried T1.2 and everything came back to a more romantic and airy sound. Voices are more alive, everything goes back to normal at the cost of a little bit of resolution, but with the more analytical/clean signature of the amplifier this is no big problem. On Elise I had the feeling that T1.2 is too polite and cannot keep the speed of some specific tracks, here I think it adds the small dose of musicality we need on specific tube combos like this one.
> 
> 
> 
> ...


What you describe about T1.2 is exactly why i keep My T1 it is a musical headphone not very dynamic, not very detailled, not extended soundstage not the best slapping bass...... For long listening session on Euforia (a bit cleaner than Elise) you have a very pleasent headphone comfortable and that just let you enjoy music and relax. You do not focus to much on details that are exposed by Verité due to much more sensibility and dynamic.  
I have HD800 for details/soundstage the one I like for live recording but the one I hate with bad recorded/mixed track !


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## OctavianH (May 4, 2021)

hpamdr said:


> What you describe about T1.2 is exactly why i keep My T1 it is a musical headphone not very dynamic, not very detailled, not extended soundstage not the best slapping bass...... For long listening session on Euforia (a bit cleaner than Elise) you have a very pleasent headphone comfortable and that just let you enjoy music and relax. You do not focus to much on details that are exposed by Verité due to much more sensibility and dynamic.
> I have HD800 for details/soundstage the one I like for live recording but the one I hate with bad recorded/mixed track !



I fully agree with you, this is how I see it. For me on Elise the synergy with T1.2 was good, but with 6SN7 and 6AS7 the sound was not clean as I would like it. I had several albums I like and listen a lot which sounded somehow grainy. This is the reason I switched to KT66 family and also preferred silver interconnects. They removed that harshness and made T1.2 sound better. The best combination I was able to find on Elise for T1.2 was the Tung Sol 5998 with Psvane CV181T2. A very detailed combo with a lot of good bass, magic was happening. I have a feeling that magic is also happening on Eternity with GEC KT66 and GEC L63 brown base clear glass combined with T1.2. It adds some emotion to a clean and very full sound. And this full sound somehow lacks soundstage which T1.2 is able to add. OK, does not sound crystal clean like Verite Open, but I prefer it.

Now, regarding HD800, I owned in the past Audio Technica ATH-ADX5000. That was HD800 on steroids, if you ever have the chance to try it, you will not regret it. It is a neutral headphone but the bass is better, the amount of detail and clarity is huge, same as the soundstage. You are at a jazz concert in the first rows. I sold it because I rarely go to a jazz concert, and for rock I prefer to have T1.2 and Verite Open. But still, I respect it and recommend it, it is an incredible headphone.

PS. I love T1.2, I am already at the second pair, but it was discontinued. So, willingly or not, I have to move on.


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## OctavianH

This has nothing to do with UltraSonic but I will share it, it is interesting. 
There are some recent pictures of WBA 2A3 amplifier, including the inside.
Cool stuff, sorry for offtopic.

On topic, the artist in me wanted a black and white photo. LOL


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## hpamdr

OctavianH said:


> This has nothing to do with UltraSonic but I will share it, it is interesting.
> There are some recent pictures of WBA 2A3 amplifier, including the inside.
> Cool stuff, sorry for offtopic.
> 
> On topic, the artist in me wanted a black and white photo. LOL


Next time, you can test Sepia...


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## OctavianH

Sepia does not preserve those nice white meters, but the Black & White filter from my phone does.


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## OctavianH (May 7, 2021)

This evening and Friday Beerday started with some unpleasant surprises. First of all, Eternity is fine. But I want to share with you my findings. They are related to a GEC KT77 pair I had the chance to buy at a decent price, not tested. No problem, I measured it and it was quite unbalanced. But since I have another pair similarly unbalanced of Genalex KT77 I decided to pair them mixed.





Yep, same date codes, all seems fine. Measured, well, not what you would expect:





But if we look here, we have 2 strong and 2 weak which pair decently, so I paired them mixed:





Look fine, isn't it? This is what I would say also. Now, before deciding to pair them like this I looked a little bit at the construction.





Both seem similar, except that GEC have a smaller base:








Very close almost identical isn't it? This is what I had thought and said, ok I match them mixed and have 2 decently matched pairs, one "weak" and one "strong".
But another strange thing was that my expected bias point was around -16V for a KT77 according to the datasheets. Well, the "weak" pair was around -16.5V while the strong one around -19V. So I said, something fishy. However, encouraged by the measurements I have decided to try the weak pair on Eternity. The surprise was that the currents shown by the meters were much lower and different than expected for one tube and on the other the meter was jumping high and low. I stopped immediately the amp. I said, hmm, on the tube tester these are not measuring correctly even if I waited 15 mins for each of them to be sure. Being very confused I said, maybe I am measuring wrong and they are, in fact matched, since on the amp all looks fine for the stronger tube and in fact, was close to the other I thought it is weak.
So I decided to make another try, only with GEC KT77. I put my both my GEC KT77s like strong one where the meter was set and the weak one on the other channel and set bias for the strong. I said, fine, one might go under 15mA but at least we are not burning anything. Of course, no headphone was plugged in. Starting the amp I had 22mA on the strong one but I was expecting more (around 24mA).
Shutting down the amplifier, waiting a few minutes, then switching the output meter for the weak tube made me find out that the current of the other was around 18mA. I was greatly surprised, I was expecting under 15mA according to how unbalanced were measuring. So I said, both currents look fine and on the amplifier these are much closer to what I need than I measured, so I'll just plug the headphones.
But when I plugged my headphones, with Volume = 0 of course, I heard a low frequency "brrrr" on the right channel where the weak tube was inserted (no music was playing yet). The sound was not loud, but still there, so I directly shut down and waited 5 minutes, then switched to fixed bias, put KT66 back and all works fine, thankfully!
But the experiment has not ended, I said, let's try the KT77 on Elise. And voila, on Elise the pair works fine and sound quite fantastic. Now, the one measured lower seems a little bit with a lower volume but it might be placebo, different is almost unhearable.





So now I have 2 tube amps, both started, and no problem on any of them. OK, the Elise is plugged in my lesser DAC but it sounds surprisingly good. I let Elise run almost an hour with GEC KT77 and still all seems fine. I measured the temps of the tubes and Elise and nothing is unusual.

My questions, addressed to myself and also to you guys:
1. Why KT77 (both my pairs) measure very unbalanced on DuoVac but on the amp are behaving differently and seem matched?
2. What happened with my GEC pair on Eternity? Should I try this pair again? I am quite afraid to burn or damage something, however I cannot understand why both GEC KT77 seem decently matched on the amplifier (18mA vs 22mA) and no fuse had any problem and still, I heard that sound on one of the channels, but the pair works fine on Elise? I was expecting the same sound on Elise to be sure that one tube was faulty. Is Elise able to bias individually the powers so maybe indeed those are unbalanced but maybe Elise biases them automatically different so both work and Eternity biases them with the same current so the sound appears? But why since the currents seem fine?

@SonicTrance Do you think I could have damaged something internally with my experiment even if no fuse jumped and the current seemed not to be exceeded on the meter? If I try to put these again to Eternity what risk I have to damage something I have? I mean, the output fuse protects everything or just a part of the components?

Now, guys, my story ends. I am unlucky with both pairs of my KT77 even if these both work fine on Elise. I do not think Eternity has a problem, but maybe something from the internal construction of KT77 or the electrical parameters of this tube, are causing my strange findings. I wanted to share, because we need to see why these are measuring differenty, acting strange on the amp and so on.


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## OctavianH

So, an evening with 2 amplifiers, and listening to both using 2 headphones. I have never done this in my life. I start to make amp rolling, something I always considered useless.





Many lights and tubes glow. Let's hope I will not get addicted to amp rolling. LOL.


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## OctavianH

And because it was Friday Beerday we have to celebrate it. All is fine when it ends fine. I thought I have burned today Eternity with my experiment. We measure, we calculate, we think but not always on the amplifier things go as planned. This is a bitter truth of tube rolling. But in the end, thankfully, Eternity is here to stay. Using in parallel 2 tube amplifiers and 2 DACs of totally different price ranges I had today a very interesting experience, I realized how futile is our hobby. We run and run for the perfection, forgetting to enjoy what we have. Audio-gd NFB-11.32 (some Sabre 9xxx chip, I do not remember) connected with some generic RCA to Elise sounds quite decent. OK, not as the main headphone line but I could live with it. So I will enjoy the bitterness of today's experiments, with a bitter beer, Jever, from Germany, bitter, but excellent. Cheers!


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## SonicTrance

OctavianH said:


> Do you think I could have damaged something internally with my experiment even if no fuse jumped and the current seemed not to be exceeded on the meter? If I try to put these again to Eternity what risk I have to damage something I have? I mean, the output fuse protects everything or just a part of the components?


If Eternity works fine now with your other tubes, which it does, it's fine. I wouldn't use that KT77 in Eternity again though. It might be that Elise runs the KT77 in a totally different operating point than Eternity, hence no brrr sound from Elise. I wouldn't worry about it.


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## OctavianH

SonicTrance said:


> If Eternity works fine now with your other tubes, which it does, it's fine. I wouldn't use that KT77 in Eternity again though. It might be that Elise runs the KT77 in a totally different operating point than Eternity, hence no brrr sound from Elise. I wouldn't worry about it.


Yes, I will not put it again but wait to see the next Eternity how it will accomodate EL34, "brothers" of KT77. There is something strange with my pairs of KT77, and I would not risk to damage Eternity for them. I wanted to share my experience as a warning for future Eternity owners to be a little bit careful with KT77, they might have similar experiences as me. What I will do, however, is to measure several times these pairs of KT77, maybe at different operating points, of Eternity and Elise, to see if I observe something different or unusual. And I will let Elise use them for several hours, for the same reason. If something valuable will come out of my actions I'll inform.


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## SonicTrance

OctavianH said:


> The surprise was that the currents shown by the meters were much lower and different than expected for one tube *and on the other the meter was jumping high and low.*


This is not a good sign. Sounds like the tube is leaky if the current isn't stable.


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## SonicTrance

OctavianH said:


> Yes, I will not put it again but wait to see the next Eternity how it will accomodate EL34, "brothers" of KT77. There is something strange with my pairs of KT77, and I would not risk to damage Eternity for them. I wanted to share my experience as a warning for future Eternity owners to be a little bit careful with KT77, they might have similar experiences as me. What I will do, however, is to measure several times these pairs of KT77, maybe at different operating points, of Eternity and Elise, to see if I observe something different or unusual. And I will let Elise use them for several hours, for the same reason. If something valuable will come out of my actions I'll inform.


KT77 in itself shouldn't be a problem for Eternity. It has to be the tubes themselves.


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## OctavianH

SonicTrance said:


> This is not a good sign. Sounds like the tube is leaky if the current isn't stable.



Yes, I have to investigate. But I doubt both pairs are problematic, I will try to measure them at the operating points of Elise where they should be stable if they work in Elise.
This is no problem of Eternity, but a problem of the tubes, but I want to investigate more, since I doubt 2 pairs of KT77 are problematic and have the same problem. I'll keep them on Elise working for 10-20 hours, just for fun. Then measure them again. We'll see if they match initial measurements, I saved all the data.


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## UntilThen

What happen to the beer here? I'll share my whisky here. Will get a new one every month.


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## UntilThen




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## UntilThen

Susvara thread gives me headaches. So I have to retreat here and talk beer and whisky instead.


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## hpamdr

UntilThen said:


> What happen to the beer here? I'll share my whisky here. Will get a new one every month.


Nad M51 pairs better with Royal Crown


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## UntilThen

Hey Octavian, sorry about your GEC KT77. As a matter of fact, my seller won't be parting with his GEC KT77 so yeah just as well. Saves me $450. I won't be buying tubes unnecessarily now. I think I have enough.


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## OctavianH

UntilThen said:


> Hey Octavian, sorry about your GEC KT77. As a matter of fact, my seller won't be parting with his GEC KT77 so yeah just as well. Saves me $450. I won't be buying tubes unnecessarily now. I think I have enough.



I would say the war is not lost. Those work on Elise and I will continue to find out why they create me problems on Eternity.

By the way, judging by the fact that I've seen those 3 bottles of whiskey a few years ago near another amplifier I have a feeling you are just collecting them and not drinking.
I have to admit, I also collect a bottle of whiskey. The reason is that I got it as a present and I do not like whiskey. LOL


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## UntilThen

hpamdr said:


> Nad M51 pairs better with Royal Crown


Yup was looking at that - https://www.danmurphys.com.au/produ...al-fine-de-luxe-blended-canadian-whisky-750ml

But I reckon I like Japanese whisky - this one - https://www.danmurphys.com.au/product/DM_859242/hibiki-harmony-whisky-700ml


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## UntilThen

OctavianH said:


> I would say the war is not lost. Those work on Elise and I will continue to find out why they create me problems on Eternity.
> 
> By the way, judging by the fact that I've seen those 3 bottles of whiskey a few years ago near another amplifier I have a feeling you are just collecting them and not drinking.
> I have to admit, I also collect a bottle of whiskey. The reason is that I got it as a present and I do not like whiskey. LOL



The WildTurkey Longreach is new and will be open tonight for a birthday celebration. The other 2 Japanese ones I have to keep.... Glenfiddich 18 yrs old was bought in 2018 coming back from a holiday in Taiwan.


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## UntilThen

Did you see the Abyss 1266 TC website. They have my same Samurai whisky.  

https://abyss-headphones.com/pages/abyss-ab-1266-phi-reference-headphone


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## OctavianH

UntilThen said:


> The WildTurkey Longreach is new and will be open tonight for a birthday celebration. The other 2 Japanese ones I have to keep.... Glenfiddich 18 yrs old was bought in 2018 coming back from a holiday in Taiwan.



OK, I cannot compete with your three fancy bottles, but I do my best. Here you are, Eternity with a bottle of whiskey and 2 Svetlana 6H13C, you can imagine those are 2 bottles of vodka.


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## OctavianH

UntilThen said:


> Did you see the Abyss 1266 TC website. They have my same Samurai whisky.
> 
> https://abyss-headphones.com/pages/abyss-ab-1266-phi-reference-headphone



Aha, nice. You know why there is not picture with a bottle of beer and a headphone on any reseller? 
Because all drink it and keep the whiskey. LOL (was a joke, I hope you don't mind).

When I look at LCD-4 and Abyss 1266 I see the same thing: more than 600g. Verite Open has 430g and I think it is too heavy. T1.2 is much more comfortable for me.


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## OctavianH

SonicTrance said:


> This is not a good sign. Sounds like the tube is leaky if the current isn't stable.



This happened at first try when 1 GEC weak and 1 Genalex weak were inserted, and happened to the Genalex. With GEC nothing like that, just the "brrr" sound.
I remember a few years ago I had a similar problem on Elise. I tried to use WE 421A with Siemens C3G and had the same issue, a sound on one of the channels (the same right channel). At that time I was using the T1.2. So I think it might be an issue with bias/gain or something.


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## hpamdr

UntilThen said:


> The WildTurkey Longreach is new and will be open tonight for a birthday celebration. The other 2 Japanese ones I have to keep.... Glenfiddich 18 yrs old was bought in 2018 coming back from a holiday in Taiwan.


I like a lot WildTurkey Longranch but it is like Jack Daniels a Bourbon (corn whiskey).  The Japanese whisky are made with a lot of precision and i find then a bit over-priced and a bit dry for may taste.  I prefer much more Islay whiskey with a strong smokey taste like Laphroaig Triple wood... (300b taste vs SS taste for Japanese)


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## hpamdr

OctavianH said:


> This happened at first try when 1 GEC weak and 1 Genalex weak were inserted, and happened to the Genalex. With GEC nothing like that, just the "brrr" sound.
> I remember a few years ago I had a similar problem on Elise. I tried to use WE 421A with Siemens C3G and had the same issue, a sound on one of the channels (the same right channel). At that time I was using the T1.2. So I think it might be an issue with bias/gain or something.


To me this is more an issue with some NOS tube you got from part-time tube seller. One on a pair is  just a bit defective and you are unlucky ! 
Seller was honest to say that the tubes are untested and do not accept return... This is normal risk taking even if it taste bad but really common in quality measurement or risk analysis when you cumulate not so good paths.


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## OctavianH (May 8, 2021)

hpamdr said:


> To me this is more an issue with some NOS tube you got from part-time tube seller. One on a pair is  just a bit defective and you are unlucky !
> Seller was honest to say that the tubes are untested and do not accept return... This is normal risk taking even if it taste bad but really common in quality measurement or risk analysis when you cumulate not so good paths.


Yes, I agree. I only try to understand, same pair of C3G worked in other combinations, the WE421A the same on Elise. Now, this pair of KT77 works on Elise.

As a side note, these KT77 get quite hot on Elise, similar with KT88. I have a personal heater here near me.


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## UntilThen

OctavianH said:


> Aha, nice. You know why there is not picture with a bottle of beer and a headphone on any reseller?
> Because all drink it and keep the whiskey. LOL (was a joke, I hope you don't mind).
> 
> When I look at LCD-4 and Abyss 1266 I see the same thing: more than 600g. Verite Open has 430g and I think it is too heavy. T1.2 is much more comfortable for me.



Having Korean beer and wagyu beef now. After the bourbon whisky I can wear the LCD4 all night.


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## UntilThen

This is Korean 300b tube.


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## OctavianH

And this is KT170, new shipment arrived:


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## OctavianH (May 8, 2021)

I bet you guys wanted some action, isn't it? Too many beers, steaks, off topic. So, let's have some action and there is no better and more beautiful action than tube rolling!

So, for this Saturday I said, let's have something exotic, let's forget about my principle of "no adapters, no top cap". Let's make something beautiful, something *RED* guys!





Ok, here we are, Philips EL3N in dual adapter to 6SN7 with Mullard EL32 on output in adapter to 6V6! That's the most uncommon combo until now.
What was really strange is that I was expecting around -7.5V at 180V/4mA according to the datasheet of EL3 (couldn't find graphs for EL3N but I think these are similar)





Well, the bias went around -6.3V this making possible the use of this dual EL3N input combination at my fixed grid bias set for 6J5.





Regarding the signature, this takes Eternity a little bit towards the OTL style of sound, romantic, euphonic, less detail, more tubey than analytic. EL32 is a very special tube for me, very emotional, I was always using it to compensate some 6AS7G or even KT tubes on Elise. I miss the punchy articulated bass, but the voices and piano are better, and overall it is a warm sound. Cannot say I dislike it, I was hoping to add some romance to my table with KT77 but the story from yesterday was not so successful. I will not use this on a daily basis, it was only a demonstration and I wanted to verify my bias voltages, but dual EL3N can be a solution to 6V6 or 6L6 lack of power. Today I remembered the beauty of the EL tubes on neutral/analytical amplifiers. These bring back emotion at the price of clarity and detail. On Elise which was a warm amplifier I never wanted to use these, even if I have 8 pieces of EL3N. Here on Eternity, EL tubes are definitely a nice experience.

*Grid biases:*
2 x EL3N -> 6SN7: -6.3V (180V/4mA)
EL32 -> 6V6: -17V (200V/20mA)


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## OctavianH (May 9, 2021)

Going back halfway to EL32 and L63, half of the euphony was gone but a more clean sound came back. Eternity is responsive to tube rolling. I think a bigger quantity of that euphony was caused by the EL32, because outputs seem to be a little bit more pronounced influence in overall tone, but even in this case the inputs have for sure, their own influence. So both stages affect the signature and tube rolling makes sense on both levels. Problematic are the adapters, I will think if it makes sense to buy EL3N->6V6, EL11->6V6 and so on. Or maybe just a pair of 6M6G. Having countless of possibilities I think I have to focus, if possible, on "no adapter" combos. And in the end, I wanted an amplifier for KT66, so a driver to make the sound more emotional while the output remains KT66 is one of my main goals.


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## OctavianH (May 8, 2021)

Last try for today, EL3N with KT88.





It is a little bit too warm for me, the same as with KT66. But might be a very nice combo for more neutral headphones like HD800. I would not use this on T1.2.
Conclusion of today's experiments is that Eternity is a good place to try EL tubes, EL3N sounds good, warm, melow and EL32 in output is also a quite good solution.

What next? Well, I might try sometimes in the future EL38 as output, another thing would be EL34 and then some more 6J5/6C5 variants. But of course, we will see.
In the meantime I hunt a pair of Psvane KT88T2 to have a spare part, these are so good I do not want to part with them and @UntilThen is making them famous.
More than this, I think Psvanes are not produced anymore, let's hope I'll find a new pair. If not, these should last me a lifetime at 200V/20mA how we use them in Eternity.

Ok, too much on topic, back to Beer mode. I've turned my Tube rolling switches OFF, EL3N (in dual adapter to 6SN7) works perfectly with my fixed bias and this pair of KT88 biases the same as KT66. Tube rolling off means beer rolling on. We will see in the next days what will happen,  I wait for the next Eternity to be released so a more wise and experienced guy will come into the light of the stage. If we both have the same grid bias points for several tube types I'll update the first post and table with some values we consider decent to be used in Eternity for people without a tube tester. Let's hope we will be right, but about this we will know more in the next months.

Now, time for me to go drink a beer with this guy:


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## UntilThen

I have a pair of Mullard EL32 coke bottle smoke glass but not sure if I get to use it again. I intend to keep Odyssey look clean and smart.


----------



## SonicTrance

@OctavianH 
Nice to read your impressions and that you're having fun tube rolling!  



UntilThen said:


> I have a pair of Mullard EL32 coke bottle smoke glass but not sure if I get to use it again. I intend to keep Odyssey look clean and smart.


Not in Odyssey you can't. At least not as power tubes.


----------



## UntilThen

SonicTrance said:


> Not in Odyssey you can't. At least not as power tubes.



No worries, I am not concerned about wanting to use EL32 in Odyssey. If I could use no other power tubes but just KT88 and EL34, I'm perfectly fine with that. These tubes are the nucleus on which the others spin around in orbit.

I'm on the other hand more engrossed with how I want the front panel of Odyssey to look. I'm debating....  hard decision here. I need Jon Iver. 

A


B


C


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## hpamdr

I like the simplicity of C just missing output headphone plug also on front... unless you want it on top or use your speaker wire only..

If you want output signal meter, both A/B have on common that the meter is in front of the input/driver tube. 3 knobs Volume, and two function switches.  
If you do not have two additional switches, you can also group meters side by side, then knob, then plugs ... 





@SonicTrance Tomas is for sure better than me and next to the design, you have the usability to take in consideration. 

What i see from @OctavianH photo is that the nice glow of the meters add visual enjoyment and balance the light. It is not useful for me for me but very nice to see !


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## OctavianH

UntilThen said:


> I'm on the other hand more engrossed with how I want the front panel of Odyssey to look.


It depends on how many elements you want to have on the front panel. I personally think Eternity looks better than Citadel by alternating switch with meter. 

Regarding tubes, well, you may be surprised with how some tubes work on these amplifiers. My core tubes were KT66 and 6J5 and now I use KT88 and EL3N.


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## hpamdr

OctavianH said:


> It depends on how many elements you want to have on the front panel. I personally think Eternity looks better than Citadel by alternating switch with meter.


Citadel is larger than Eternity and in both configuration the meter is in front of an input tube for each side... For your compact eternity the best match is he one you have 


OctavianH said:


> Regarding tubes, well, you may be surprised with how some tubes work on these amplifiers. My core tubes were KT66 and 6J5 and now I use KT88 and EL3N.



Next try should be EL11 if you have tube and adapter to 6J5 and with KT88 (this is in Euforia a good and powerful match).
And next try 6SL7 with EL32 with relaxing music.... or some 60/70 pop like :


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## OctavianH

I do not have any EL11 adapters except single 6SN7 which is not usable. 6SL7 with EL32 would be possible soon.


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## OctavianH (May 9, 2021)

hpamdr said:


> Citadel is larger than Eternity and in both configuration the meter is in front of an input tube for each side... For your compact eternity the best match is he one you have


Yes, meter in front of a tube socket is more a matter of finding space on the inside for the meter. My small chasis created a lot of problems, because I also have the stepped attenuator which is quite big. Tomas was a magician to fit all these inside that small chasis.

Later edit:

Morning coffee with a view, EL3N + KT66:





This combo adds some distortion and bite to the electric guitar. For sure not for classical or pop, but on specific genres which are more aggressive, the polished and clean sound of Eternity and 6J5 is not the perfect choice. Well, this one is the solution in that case.

*As a sidenote about this specific EL3N double adapter to 6SN7 and EL3N in Eternity:* This adapter is a monstrosity, I broke one using it 2 times in Elise years to have that 6 x EL3N everyone tried and now I have only this one. Besides the fact that the EL3N socket itself is hard to use, these cheap plastic ones are even harder. But, the adapter allows rotation of the 6SN7 base and in this particular case of an amplifier with the guiding pin of the tube sockets on the left (as you look on it) it is very useful.
Now, regarding EL3N, if I turn the volume to 0 I hear a very small hum. But this is a problem of my EL3N tubes or maybe adapters, I had the same on Elise. I do not think this will damage in any way Eternity as it is barely hearable, but I thought it is worth mentioning. Eternity is dead silent, but this double EL3N combo is not. EL32 were dead silent too.

And in the end, since we are at the EL3N chapter some fine things to read:

EL3N Single Ended Sakuma style

and some nice comments here:

Old Europian Pentodo Philips EL3N


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## hpamdr

OctavianH said:


> Yes, meter in front of a tube socket is more a matter of finding space on the inside for the meter. My small chasis created a lot of problems, because I also have the stepped attenuator which is quite big. Tomas was a magician to fit all these inside that small chasis.
> 
> Later edit:
> 
> ...


Some El3N tubes are prone to heating noise but usually not loud enough to be very annoying.
Yes EL3N add some kind of echo/harmonic when used as driver/input this is even more accentuated with KT66 or EL3N as output. But it add some distortion that some find nice and specially because it create an effect that could enhance soundstage at least in Elise.. 
The one that use dynamic and sensitive headphone can find it a bit "too much" but at the end it is all a personal choice/taste and synergy.


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## OctavianH (May 9, 2021)

hpamdr said:


> Some El3N tubes are prone to heating noise but usually not loud enough to be very annoying.
> Yes EL3N add some kind of echo/harmonic when used as driver/input this is even more accentuated with KT66 or EL3N as output. But it add some distortion that some find nice and specially because it create an effect that could enhance soundstage at least in Elise..
> The one that use dynamic and sensitive headphone can find it a bit "too much" but at the end it is all a personal choice/taste and synergy.


Yes, EL3N add some distortion which in my specific case is needed. And you were right when you advised me to try 6L6 with EL3N or EL11. If 6L6 felt underpowered with 6J5/6SN7 with EL3N as input it starts to sound better. So yeap, EL3N is not very detailed, not very clean, somehow a warmer variant of EL11, but in some cases, when the other pair sounds dull or it is too polite, well, it does the trick. Honestly these still sell at around 25 EUR/piece at Acoustic Dimension in Holland which seems to me a decent price for what they can do. I never liked these because Elise was too warm for them. I guess they were better in Euforia or more neutral amplifiers. In my case, EL3N + Elise + T1.2 was for sure the wrong path. Now I start to reconcile my relationship with them. Not spectacular but useful to have at home.


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## UntilThen

Cheers


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## UntilThen

What tube should I roll now?


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## hpamdr

OctavianH said:


> Yes, EL3N add some distortion which in my specific case is needed. And you were right when you advised me to try 6L6 with EL3N or EL11. If 6L6 felt underpowered with 6J5/6SN7 with EL3N as input it starts to sound better. So yeap, EL3N is not very detailed, not very clean, somehow a warmer variant of EL11, but in some cases, when the other pair sounds dull or it is too polite, well, it does the trick. Honestly these still sell at around 25 EUR/piece at Acoustic Dimension in Holland which seems to me a decent price for what they can do. I never liked these because Elise was too warm for them. I guess they were better in Euforia or more neutral amplifiers. In my case, EL3N + Elise + T1.2 was for sure the wrong path. Now I start to reconcile my relationship with them. Not spectacular but useful to have at home.


If you like 6L6/6V6 with EL3N, just try to get good adapter to 6J5 and same for EL11 Your amp deserve better stuff. (_I also dislike the dual adapter with plastic and pcb and it is one of the worse about durability and build quality. I'm even not sure that the G2-A wire have a resistor)_.


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## OctavianH (May 9, 2021)

UntilThen said:


> Cheers


So the unbelievable happened and you opened the whiskey bottle.

Then, it is time for me to tell you which burger is the best burger in town, of course Bitburger. Cheers.





Coming back to our activities, I try now EL3N with 6V6 and sounds good, it seems EL3N saved 6V6 and 6L6 in Eternity.
Of course, these are not beating KT66 or KT88 but now they have a word to say.





And another thing I've observed is that after more hours of use, EL3N starts to raise the current:





Yesterday at -6.3V had 4.2mA and now it goes towards 4.5mA. I am still fine, but I do not want to exceed 5mA. Maybe these are still in the burn in phase and start to awake and go to the expected bias? I have to be careful, the first pair which starts to behave differently in terms of bias/currents, this means I have to watch from time to time these meters even if I was on the good operating point some hours ago.

Soundwise, Philips EL3N + Tronix 6V6G (I still do not know who manufactured these, might be GEC/Brimar) has a strong bass and sounds quite good. Voices sound great with this one. A great combo, never thought that 6V6 will sound like this on Eternity. I think I'll try later some other brands of 6V6 because all of them sound different and I want to hear them.


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## UntilThen

Oh gawd if you only know how good this Brimar 6L6GA sound...


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## OctavianH

hpamdr said:


> If you like 6L6/6V6 with EL3N, just try to get good adapter to 6J5 and same for EL11 Your amp deserve better stuff. (_I also dislike the dual adapter with plastic and pcb and it is one of the worse about durability and build quality. I'm even not sure that the G2-A wire have a resistor)_.



I will add this to my "To do" list. For some tests, to see how things are going, this is fine, but yes, as a "test device".
I can measure to see if they put a resistor BUT this means I have to remove EL3N from the adapter and we know how a big mistake it would be, this is how I broke the other.

@UntilThen If you have Alec Baldwin in your livingroom drinking your whiskey you should definitely roll 300B.


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## hpamdr

UntilThen said:


> What tube should I roll now?


This is time for Jack Daniel's 'Single Barrel' Special Release !


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## UntilThen

By far the most beautiful looking and sounding tube hic.



cheers


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## OctavianH

UntilThen said:


> cheers



You switched to white wine? Don't mix them because at the next glass you'll have Alicia in your room.


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## UntilThen

I didn't mix them. Does this look like it's 1/3 gone?

WHat's the next song !


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## UntilThen

I'll play you the next song


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## OctavianH

UntilThen said:


> I'll play you the next song




I was at this one:



But you definitely made a good choice. I have this AC/DC CD somewhere, but if I start to look for it we hear tomorrow. Good that youtube saved us. LOL


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## UntilThen

The night just started


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## OctavianH (May 9, 2021)

UntilThen said:


> The night just started




Do not forget Back in Black. I think it is their best one. Especially Hell's Bells.


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## OctavianH (May 9, 2021)

Ok, let's talk about different brands of the same tube type and their impact on Eternity. Someone before told us that basically the electrical paramaters of a tube matter and all brands should sound more or less the same. Well, up to a point. Today I tried 3 different 6V6G in Eternity with 2 x EL3N as inputs. Each pair sounds differently. OK, we can say that in general terms, synergy is good and overal signature is close, BUT even the tube brand matters. For example, first pair I described here has the best bass, most articulated, biggest quantity and smaller soundstage. Next try was Westinghouse 6V6G which was more towards neutral, unexciting for me compared to the first one. And the third was David and Goliath:





Sylvania 6V6GT/G, smaller in size and brighter, typical Sylvania sound (similar with Sylvania 6SN7 in terms of signature). Brighter, more detailed, wider soundstage. Totally different from the other 2. And even those were different one from each other. OK, first 2 pairs are ST shaped bottles, with different coating, this one is different, but I say even rolling different 6V6G makes sense and provides a difference. Synergy is good for all of them, but we have different sound based on what we choose.


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## hpamdr

UntilThen said:


> I didn't mix them. Does this look like it's 1/3 gone?
> 
> WHat's the next song !


you got sword back !


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## UntilThen

hpamdr said:


> you got sword back !



You have no idea.... after a bit of whiskey how I manage to take such pictures.


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## OctavianH (May 9, 2021)

Guys, just found out that KT55 exists. There is a pair selling on Ebay in US at a small price compared to KT66.
I think this might be compatible with Eternity but biases at -30V for 20mA/200V?




I have to admit I never heard about this tube before.

Later edit: WOW 50 Volt heater?


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## triod750

50 volt heater?


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## OctavianH

triod750 said:


> 50 volt heater?



This is exactly what I was looking. I have to admit that looking at the picture and pin layout I did not pay attention to the Vh. 52V. WOW.


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## hpamdr

OctavianH said:


> Guys, just found out that KT55 exists. There is a pair selling on Ebay in US at a small price compared to KT66.
> I think this might be compatible with Eternity but biases at -30V for 20mA/200V?
> 
> 
> I have to admit I never heard about this tube before.


Just have to heat at 52V, hope you did not clicked on the ebay link !


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## OctavianH

hpamdr said:


> Just have to heat at 52V, hope you did not clicked on the ebay link !



Absolutely not. I was looking and when I saw the picture said to myself "hmm, these look identical with GEC KT66 grey glass". Then I saw the KT55 on the boxes and googled it, found the datasheet on Valve museum and looked a little bit on the pinout, seemed similar to KT66. What I have not done because I was not paying attention, was to look at Vh. I have to admit my brain somehow associated the shape to KT66 and never thought that these are not 6.3V. Interesting anyway.


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## triod750

But you could afford 52 volt, could you not? You are full of volt, ampere and beer. This isn't much of a problem!


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## OctavianH

triod750 said:


> But you could afford 52 volt, could you not? You are full of volt, ampere and beer. This isn't much of a problem!


I would not combine beer with volts or ampere, can be dangerous.


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## triod750

OctavianH said:


> I would not combine beer with volts or ampere, can be dangerous.


Just remove the ampere then .

I know that you are careful.


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## OctavianH

Gaining confidence in EL32 from the previous experiment with the Mullards, I have decided to measure and try the Marconi EL32. I have 4 pieces of these and I remembered from the past that these sound different than the others, towards a more neutral sound. With EL3N these were harsh, but with 6J5 they start to sound better.





What was strange measuring these 4 pieces was that 3 of them were around -16.x and one measured -18.5V for 20mA. It was not a problem for me to find a matched pair, but the question arises: If we plan to make a table with recommended values for each tube type and the tube tolerances are so wide, how can we be sure someone will not damage the amplifier? I mean, that tube measuring -18.5 at the -17V which I would propose as bias, would exceed 24mA. If we raised the value of bias around -18V to be sure no pair exceeds the limit these go much under what we desire. According to the datasheet, these should bias around -17V.


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## OctavianH (May 9, 2021)

Victory!





After hours of thinking, measurements and so on, I managed to make one mixed pair of KT77 work safely in Eternity! KT77 works! It is the strong pair, biased so both tubes are in decent range and no danger for the amplifier is possible. I monitor via the meter the stronger piece from the pair.





And what a beautiful tone, KT77 are incredible! Warm and relaxed, yet very rich in tone, exactly like I was hearing on Elise on Friday. But on Eternity this kind of tone complements the analytical/clean sound of the amplifier and sounds much better than on the already warm Elise.

Ok, I will stop here, today I learned several things, it was a day full of surprises and experiences. Now it is time to relax and listen to ... the music.


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## OctavianH (May 9, 2021)

I have to come back with some more details about the GEC KT77 in Eternity at 200V/20mA. It seems these reach over 100C and even the logo starts to degrade. These were NOS but it seems after several hours at 100C the logo starts to burn slowly. I carefully monitor the temps and also the currents, the amplifier works fine, however, these seem to be the hottest tubes used by me until now.





The logo looks darker and with some black points on it compared to yesterday, this is the reason so many have no logo at all on Ebay or other collections:





The glow is incredible, these are some of my most beautiful tubes. I love them. The sound is creamy, warm but very rich in the mid section, emotional and lively. I start to become very curious about EL34 because it has to be in the same area and I start to realize I am totally into this kind of magic. I remember what @UntilThen said yesterday on the Destiny thread that he liked most the RFT EL34 and then KT88. I start to think if he was also enjoying such kind of sound I hear now and honestly, tops everything I heard until now. Ok, might be excitement of the moment because I wanted so much to listen to KT77, but I think it is also a very good synergy of this clean and fast amplifier with a very creamy and romantic tube. Many wrote on different forums that EL34 is incredible, I have a feeling I start to understand.


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## hpamdr

OctavianH said:


> I have to come back with some more details about the GEC KT77 in Eternity at 200V/20mA. It seems these reach over 100C and even the logo starts to degrade. These were NOS but it seems after several hours at 100C the logo starts to burn slowly. I carefully monitor the temps and also the currents, the amplifier works fine, however, these seem to be the hottest tubes used by me until now.
> 
> 
> 
> ...


Glad you fixed the issues with KT77, so many experiment is really great ! 
My excitement to get my amp increase so much... _(I will not experiment with so "aristocratic" tube as i do not have any   but my list of potential good combination still grow.)_

Rolling with manual bias seems to not be so painful if you use the right parameter ! Eternity is a flexible beast in fact 

Finally the conclusion is that Eternity gives precise, cleaner and more dynamic sound than Elise. But it is a bit more sensible to tubes as sonic is less hidden by too warm tonality.


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## OctavianH

hpamdr said:


> Glad you fixed the issues with KT77, so many experiment is really great !
> My excitement to get my amp increase so much... _(I will not experiment with so "aristocratic" tube as i do not have any   but my list of potential good combination still grow.)_


 I would say you should not worry because your pair of NOS Tesla EL34 might be the best possible output in the world. KT77 destroys everything in it's path and it is, in my view, a good EL34. The amplifier sings, there is life in every note, I never heard something like this in my life. I am totally blown away. Lightwise, I have no words:





The GEC L63 inputs are very clean and full bodied and somehow complement the KT77 even if I would have said before trying them that a good match would be a more neutral input. I will try these with other variants in the next days, at the moment I cannot stop and change anything.


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## UntilThen (May 9, 2021)

A GEC KT77 is a worthy contender for the best sounding tube category but it has to compete with other equally famous siblings, namely GEC KT88, KT66, Mullard EL34 xf2, Telefunken EL12 spez, Tung Sol 6550 1960s, RFT EL39, Psvane Classic Mkii kt88. Don’t forget the Radiotron 807.

Then you step into 300b and 2A3 tubes.


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## OctavianH

UntilThen said:


> A GEC KT77 is a worthy contender for the best sounding tube category but it has to compete with other equally famous siblings, namely GEC KT88, KT66, Mullard EL34 xf2, Telefunken EL12 spez, Tung Sol 6550 1960s, RFT EL39, Psvane Classic Mkii kt88. Don’t forget the Radiotron 807.
> 
> Then you step into 300b and 2A3 tubes.


300b and 2A3 are above my price range so I doubt I will ever try them. But the results from yesterday gave me confidence that EL34 and EL38 might be as well very good on Eternity. What I heard with KT77 and EL32 gave me this feeling. KT77 is good, but it is too rare, expensive and to find a matched pair is not easy, a real winner would be, in my opinion, a tube which is easy to find at a decent price and still provides almost the same sound quality. Tesla EL34 or RFT EL34 might be the answer.


----------



## hpamdr

OctavianH said:


> 300b and 2A3 are above my price range so I doubt I will ever try them. But the results from yesterday gave me confidence that EL34 and EL38 might be as well very good on Eternity. What I heard with KT77 and EL32 gave me this feeling. KT77 is good, but it is too rare, expensive and to find a matched pair is not easy, a real winner would be, in my opinion, a tube which is easy to find at a decent price and still provides almost the same sound quality. Tesla EL34 or RFT EL34 might be the answer.


In fact your judgement is only based on NOS or NIB tubes.. For 300B you can find reissues that sound really good around 300€. As the amplifier design is in general only focused  only on 300B or 300BXLS you do not have to roll anymore and just have to get a good matched pair... With Reissue you get it matched if not you can return ! 
You can still want to roll rectifier tube this is up to you, as you can also chose to use SS rectifier.

I personally do not go in this path because one of my my hobby is to roll and the excuse is to find good combination. It fact this is an hobby by itself ! 
Many people just stay with original tube and get some spare using new production and still enjoy listening music...

About Tesla and RFT EL34 this is a kind of lottery _(much less if you are really careful_) as the production quality is not the same depending of year and place.. And for holly grail metal base EL34 it is really expensive and you can still have some measuring surprise if you only get a single pair...


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## OctavianH

hpamdr said:


> I personally do not go in this path because one of my my hobby is to roll and the excuse is to find good combination. It fact this is an hobby by itself !
> Many people just stay with original tube and get some spare using new production and still enjoy listening music...


My musial collection contains albums from garage recordings to ones with a clean and nice production. I was never able to find a combination of tubes which pleased me on all of them. More than this, from time to time, changes in the rest of the line needed adjustments also on the amplifier to compensate. So I guess my path is an adjustable amplifier to be able to roll 2-3 pairs based on my listening needs.


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## hpamdr (May 10, 2021)

OctavianH said:


> My musial collection contains albums from garage recordings to ones with a clean and nice production. I was never able to find a combination of tubes which pleased me on all of them. More than this, from time to time, changes in the rest of the line needed adjustments also on the amplifier to compensate. So I guess my path is an adjustable amplifier to be able to roll 2-3 pairs based on my listening needs.


I have some old swing recording, you have the feeling that in was recorded with a yogurt cup instead of a microphone... Low D.R. some reverb and crackle no tube combination can change it... I still like to listen to it from time to time anyway...
I never listen with my DAC/Amplifier from any online source and usually prefer to listen a complete album. For some bad recording, I just go with dynamic EQ/filter on player or on music converter...
Music converter have the advantage to not have to be processed anymore !


----------



## UntilThen

OctavianH said:


> 300b and 2A3 are above my price range so I doubt I will ever try them. But the results from yesterday gave me confidence that EL34 and EL38 might be as well very good on Eternity. What I heard with KT77 and EL32 gave me this feeling. KT77 is good, but it is too rare, expensive and to find a matched pair is not easy, a real winner would be, in my opinion, a tube which is easy to find at a decent price and still provides almost the same sound quality. Tesla EL34 or RFT EL34 might be the answer.



Depends on which 300b tubes you buy. Gold Lion sounds great and cost only $400. 

What I found out comparing the 300b and KT88 amps these few days... 

The 300b amp is not necessary better than the KT88 amp in terms of slam, punch and dynamics. Where these things are important, I actually prefer the KT88 amp. 300b amp though is unsurpassed when I listened to vocals, male or female for that matter. 300b also has astonishing sub bass that goes deep.

Having 300b and KT88 amps would be ideal.  So sail on Odyssey... sail on down under. There will be a grand reception. I will open a bottle of Hennessey XO Cognac this time.


----------



## OctavianH

Today  I do not have anymore time for rolling because I have to work, however I am able to listen to music and I have decided to continue to listen to KT77. This morning I observed something which I think makes sense to share. But before that I have to explain a little bit the context. Eternity allows a tolerance of 15-24mA for the outputs where KT77 are installed. Since my pair, which consists of 2 non identical tubes (one GEC and one Genalex), is not properly electrically matched, there is a difference of around 4mA between them at the same grid bias. Being careful not to exceed the maximum allowed 24mA I have decided to keep them in the lower part of the interval. This means 16mA for the weaker one (GEC) and 20mA for the stronger one (Genalex). All set and done. I start the amplifier and the currents start to raise slowly. Since I have only one mA meter for output stage I have set it to monitor the Genalex tube, since this one will have the highest current. When the currents raise around 21mA (I always set 1mA more than the value where I want to keep them because in the first 5-10 minutes the tubes draw more current and then when they are properly heated they go back around 1mA lower and stabilise) I think to myself "one is 20mA, other has to be around 16mA so all is fine and I am safe, I can start working". But after around 1 hour I have a feeling that there is lack of clarity in the left channel. Of course, a very slight feeling, which I am unsure about. I say, let's look again at the meters and see that the stronger tube has only 19mA. So it seems KT77 is a different animal than KT66 for example. KT66 draws around 1mA more in the first minutes and then stabilises itself. KT77 seems to draw more current in the beginning and then goes back to around 2mA. This made my weaker one go to 15mA and this is the reason I think I felt that lack of detail in the left channel. Raising the current in both tubes so now the Genalex has around 22mA and the GEC has 18mA provided me benefits in both cases. So I solved the lack of clarity of the left channel but to my surprise it also improved the clarity of the right channel. What I think it happens is that these KT77 like to operate at more than 20mA and sound better in that area. This makes me very curious to read how these work in Infinity which has output stage set to 40mA.


----------



## hpamdr

Got a new pair of GL KT66 (bias around 22V), made some experiment and found a nice sounding input tube Russian 6s5s (6C5G equivalent) 
Curently KT66 are still new and need some hours before giving the best.

This is a USSR/Russia set I plan to test on Eternity once first test with GU50 will be done !


----------



## UntilThen

When my Elekit TU-8200 was still working, the Genalex Gold Lion KT77 current production tubes sounded good on it. This is a picture my supplier send me of the pair of GEC KT77 which he now decides that he won't sell because when he tried it again, it was too sweet to his ears.  Much to my sadness of course but it's not like I have no other good tubes. Having heard many on Elekit, I do not think that the KT77 is the best but it's one of many.


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## OctavianH (May 13, 2021)

I was lucky enough to be able to try both reissues (Genalex Gold Lions made in Russia) and NOS for both KT66 and KT77 and I can say that the reissues are doing a good job. I have to admit I prefer the NOS ones but you are safe to buy a reissue and you will, most probably, be very happy. I do not know why these GEC KT77 are so rare compared to, for example KT66.

I think the 1 million dollar question is now: How are EL34 sounding on Eternity? I hope I'll be able to answer it during the weekend.


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## OctavianH (May 14, 2021)

Some more stuff today. Time for 6SL7GT, Brimar CV1985, a very neutral, clean and nice sounding tube.





And the volume knob goes to 10PM from 12PM in this case.

But today, because of the very low bias of the 6SL7GT I found that my only tube of this type barely reaches a decent amount of current.





With the trimmer at minimum I barely obtain 2.8mA. The tube is perfectly matched internally, but since my trimmer does not go to less that -0.4V I cannot raise more the current in the tube. Tomas advised the 6SL7 to be run at a special operating point of 3mA, I am close, cannot go higher. So warning, maybe my tube is measuring low, but there might be problems with the 6SL7 in Eternity.

And in the end, Friday beerday, cheers!


----------



## OctavianH (May 14, 2021)

Next in line, Cossor 6C5G. These are interesting, need more time with them. Sound quite good.




I think these are rebranded, I had no time yet to investigate and learn their story. As far as I know Cossor is similar with Colomor, UK tube company which rebranded many tubes from different manufacturers. One of my GEC KT66 is rebranded Colomor, identical sounding with GEC. We will see what is the story of these ones.
If someone knows more, please share.


----------



## SonicTrance

OctavianH said:


> Tomas advised the 6SL7 to be run at a special operating point of 3mA, I am close, cannot go higher. So warning, maybe my tube is measuring low, but there might be problems with the 6SL7 in Eternity.


That tube is a little weak but totally fine to use.


----------



## OctavianH

SonicTrance said:


> That tube is a little weak but totally fine to use.



I have observed that tubes work in input stage even under 3mA. So the tolerance of 3-5mA might be extended to -2.5mA? I quite like it, very neutral and detailed, might be a good pair for KT88 and KT77, but today I wanted to try more the KT66 so I just checked it to measure its bias and put it in the box.


----------



## SonicTrance

OctavianH said:


> I have observed that tubes work in input stage even under 3mA. So the tolerance of 3-5mA might be extended to -2.5mA? I quite like it, very neutral and detailed, might be a good pair for KT88 and KT77, but today I wanted to try more the KT66 so I just checked it to measure its bias and put it in the box.


Yes, 2.5mA is completely fine. Especially for the 6SL7 👍


----------



## OctavianH

Nothing newer on the Eastern Front. Just some light pr0n. Quite some lightning here today with these 6C5G clear glass (and some photo effects, of course). 






And these Cossor 6C5G are quite nice, beautiful tubes:


----------



## UntilThen

OctavianH said:


> Some more stuff today. Time for 6SL7GT, Brimar CV1985, a very neutral, clean and nice sounding tube.



Ah the 6SL7.... a tube I'm keenly interested in. I have 3 different types now. My supplier can get me another Brimar 6SL7 in red letters at the base which according to him is very nice. Also an Amperex 6SL7 which he say is the king of 6SL7 ...   

Further tempt me with Philips Miniwatt double D getters brown base and metal base EL34. These are not going to be cheap. I'll have to defer buying these. 

You have some very nice drivers there in the Cossor 6C5G. Congrats.


----------



## UntilThen

These Tung Sol 6550 arrived yesterday and they have incredible mid and bass. I can see how these differ from their British cousins GEC KT88.

My pair are grey plates with single O getter on top and 2 O getters on the sides. There are rarer TS 6550 in black plates with D and O getters. The earliest version from 1950 is the black plates with just a single O getter on top and these fetch a very high price now.

Don't stare too hard at my reflection in the tube because you will see Clarke Gable.


----------



## OctavianH

UntilThen said:


> Don't stare too hard at my reflection in the tube because you will see Clarke Gable.



Nice hat!


----------



## hpamdr

SonicTrance said:


> Yes, 2.5mA is completely fine. Especially for the 6SL7 👍


A variation of 6SL7 with same amplification (70) factor is the 6SC7 witch should bias a bit better in eternity...
If you want High amplification factor you can also use the triode part of 6AV6 / EBC91 but you will need an adapter to 6j5 _(this is the input tube of standard Eternity)_


----------



## OctavianH

hpamdr said:


> A variation of 6SL7 with same amplification (70) factor is the 6SC7 witch should bias a bit better in eternity...
> If you want High amplification factor you can also use the triode part of 6AV6 / EBC91 but you will need an adapter to 6j5 _(this is the input tube of standard Eternity)_


I do not see a real advantage for 6SL7 on 6SN7 or a pair of 6J5/6C5 soundwise. And since I keep my volume at half with Verite and at 60% with T1.2 I doubt high gain can provide me other advantage. I was curious, but I will not go further on the path of 6SL7. I will let others discover it. I wanted only to try one, I've tried it and now I'll stick to my path trying to explore more from 6J5 with my main outputs KT66/77/88. 

By the way, I was quite disappointed by Langrex. I asked them to measure and provide some matched pairs since they had many items in stock, which they verbally agreed, but they have done nothing. I was quite lucky to have 4 pieces of what I ordered and matched them decently by myself, but I was expecting more from those guys. Judging by the fact that I have to pay 20% more for what I order from UK I'll buy from now on only previously tested tubes with good readings.


----------



## OctavianH

Regarding these Cossor 6C5G misterious tubes:





Thinking about a date code or manufacturer, I see an "N II" or "N 11" and another N near the logo.


----------



## SonicTrance

hpamdr said:


> If you want High amplification factor you can also use the triode part of 6AV6 / EBC91 but you will need an adapter to 6j5 _(this is the input tube of standard Eternity)_


The 6AV6 is indeed the stock tube but yours and Octavians amps have been redesigned to use different tubes. So the 6AV6 can't be used as it's max plate dissipation is only 0.5W. You can however use the 12AX7 as that's a 1W tube and still mµ of 100. I'd run the 12AX7 at 2.5-3mA in Eternity.


----------



## OctavianH

SonicTrance said:


> The 6AV6 is indeed the stock tube but yours and Octavians amps have been redesigned to use different tubes. So the 6AV6 can't be used as it's max plate dissipation is only 0.5W. You can however use the 12AX7 as that's a 1W tube and still mµ of 100. I'd run the 12AX7 at 2.5-3mA in Eternity.


By the way Tomas, since you advise to use different tubes at different operating points in the same circuitry, it is not clear to me if the 3-5mA range is advised to have the tube in the "more linear" zone or if the circuit itself does not work at less that 3mA. For example, 6SL7 seems to work fine at 2.5-3mA and it seems 12AX7 is in the same situation.


----------



## OctavianH (May 15, 2021)

A normal Saturday evening with Eternity. KT66 + L63. This evening on fixed bias because we relax.


----------



## SonicTrance

OctavianH said:


> By the way Tomas, since you advise to use different tubes at different operating points in the same circuitry, it is not clear to me if the 3-5mA range is advised to have the tube in the "more linear" zone or if the circuit itself does not work at less that 3mA. For example, 6SL7 seems to work fine at 2.5-3mA and it seems 12AX7 is in the same situation.


The circuit works optimally at 4 and 20mA respectfully for input and output stages. That's where the current ranges comes from. The gyrators are most "happy" at 4 and 20mA. They do however still work at say 2.5mA and 25mA, just not optimally. Now, if you can hear that difference is another matter. Most likely not.

Regarding the 6SL7 and 12AX7 they need to run at slightly lower current as they're weaker tubes with a max anode dissipation of 1W. So, to not put too much stress on those tubes I recommend the lower current.


----------



## OctavianH (May 16, 2021)

This evening is dedicated to Draconian. This swedish band is incredible, the last album made me listen on repeat several weeks on Elise and it seems it does the same on Eternity. This is not for everyone, but it is top class.



Eternity glows and sounds incredible.


----------



## SonicTrance

OctavianH said:


> This evening is dedicated to Draconian. This swedish band is incredible, the last album made me listen on repeat several weeks on Elise and it seems it does the same on Eternity. This is not for everyone, but it is top class.


I usually don't listen to this kind of metal music but really liked this song actually. Another Swedish rock band I listen to sometimes is Sabaton!


----------



## hpamdr

SonicTrance said:


> I usually don't listen to this kind of metal music but really liked this song actually. Another Swedish rock band I listen to sometimes is Sabaton!



I prefer this swedish citizen


----------



## OctavianH (May 16, 2021)

SonicTrance said:


> I usually don't listen to this kind of metal music but really liked this song actually. Another Swedish rock band I listen to sometimes is Sabaton!




Sabaton are ok, except those socialist symbols they always like to put on their covers. I do not listen to them but I've seen them live a few times and they do a nice show.

Edit: The Vintage Caravan are incredible. What they are doing with those guitars is some killer stuff. This is a song for KT66.


----------



## OctavianH

These Cossor 6C5G are somehow lighter than the GEC L63 (both versions) and pair better with KT88. Warmer inputs are adding to much bass to KT88, sometimes of worse quality, but these are neutral enough to let KT88 shine. This is a combination I will keep in my mind.






PS. Today Elise left my house to meet another owner. An era has ended, another era continues. Let's hope I will decypher more from the mysteries of Eternity.


----------



## hpamdr

OctavianH said:


> These Cossor 6C5G are somehow lighter than the GEC L63 (both versions) and pair better with KT88. Warmer inputs are adding to much bass to KT88, sometimes of worse quality, but these are neutral enough to let KT88 shine. This is a combination I will keep in my mind.
> 
> 
> 
> PS. Today Elise left my house to meet another owner. An era has ended, another era continues. Let's hope I will decypher more from the mysteries of Eternity.


You should try the regular 6J5 full metal normally easy to find or European 6J5MG...






// i have a preference for the 6J5MG just because I can get Visseaux tubes


----------



## OctavianH (May 19, 2021)

I'll let on my "to do" list the 6J5MG. Now I am handling more interesting things.





And these are the Tesla EL34.





These can be found at good prices, with a little effort, on Ebay. I was lucky to find a pair which is electrically matched under 10%, almost 5%. Having a little bit unde 2mA between them on the amplifier let's me play a little bit with the Bias and keep them at around 19mA/21mA without being so stressed about the +3mA bump at startup. Because these behave similar to what I was reporting about KT77 (hot tubes, draw up to 3mA more at startup then slowly decrease and stabilise after 15-20 minutes). These are also muscular tubes, in the first seconds nothing happers, the inputs reach 4mA and only after some seconds start to raise the current, in the first seconds slowly but from 10mA->20mA raise fast, you panic a little bit, then again slower draw more and more). Hard to tame beasts.





Soundwise, clean and energetic tubes with very good dynamics and quality bass, towards KT77 but not as refined as GEC KT77. For the price, I would say a "wow". I like this sound, for sure GEC KT77 remains for me the best I have found on Eternity, but since those are so rare and usually unmatched, I would say that these might be a best buy on Eternity, at least for the sound I am looking for. I will keep these for several days because they were NOS and need burn in, but I have a feeling these have 70% of the magic of GEC at the 25% of the price. Good catch, EL34 on Eternity.


----------



## OctavianH (May 19, 2021)

Something interesting about these EL34: the pins are thicker than other tubes. So the grip on the sockets is quite big. I think I'll use socket savers with these, just to be sure I am not damaging amplifier sockets. Anyone else saw something like this?





Said and done:





And now Eternity looks like a mosque from Istanbul LOL


----------



## OctavianH

Lightwise all good. But with these socket savers I have a feeling there is more noise. That's life, you cannot have all. I have a slight feeling that the bass is not so punchy and precise, there is a slight slow down in the overall dynamics and somehow a little bit less overall detail. But most probably my brain is messing with me, sometimes we hear what our brain tells us to hear. I had the same feeling on Elise and LittleDot amplifiers when I have used the same socket savers, but I was never convinced it is not Placebo.


----------



## SonicTrance

OctavianH said:


> Lightwise all good. But with these socket savers I have a feeling there is more noise. That's life, you cannot have all. I have a slight feeling that the bass is not so punchy and precise, there is a slight slow down in the overall dynamics and somehow a little bit less overall detail. But most probably my brain is messing with me, sometimes we hear what our brain tells us to hear. I had the same feeling on Elise and LittleDot amplifiers when I have used the same socket savers, but I was never convinced it is not Placebo.


Try one channel with socket saver and one channel without. See if you hear a difference.


----------



## UntilThen

I will use socket savers from day one until I’m settle down with tube rolling.


----------



## hpamdr

OctavianH said:


> I had the same feeling on Elise and LittleDot amplifiers when I have used the same socket savers, but I was never convinced it is not Placebo.


The socket saver i use are ceramic socket. You just have to be careful as you do not have center pin. 
For sure you do not have any loose connection nor too small wire !
This is the one i use you can even discuss price if you want than one but avoid the one with larger ring in the pin.


----------



## UntilThen

I'm very sorry I've not send out the tubes Mr Tomas. I will at the latest on Sat morning. Been busy at work but I'm thinking of Odyssey. 

I want it to have some bite in the top end, lucid and textured mids and luscious, gut hitting tsunami bass. Soundstage as wide as the Opera House and symphony sound like the Beethoven 9 from this orchestra.


----------



## UntilThen

And saxophone to sound like this saxophone. With the waterfalls and beautiful scenery of course. That's a given right, Tomas?


----------



## hpamdr

UntilThen said:


> And saxophone to sound like this saxophone. With the waterfalls and beautiful scenery of course. That's a given right, Tomas?



For the scenery, I'm pretty sure Tomas will let you take picture of odyssey on the beach.... or near _Lake Burley Griffin 
_


----------



## OctavianH (May 20, 2021)

SonicTrance said:


> Try one channel with socket saver and one channel without. See if you hear a difference.



I do not want to insert EL34 directly in Eternity, I have done this yesterday and I think the grip was a little bit too much.

The socket savers I use are decent, for me they look similar with the teflon sockets:





And my tube rolling journey is approaching to the end, I have done what I have said will do, tried the EL38:





From 3 pieces of EL38 I was able to make a matched pair, one double O-getter and one double cup getter. EL38 sounds good, very emotional for piano, voices. A kind of EL32 on steroids with bigger and bolder sound. But for me I would say it does not match the EL34 or KT77. I think I will stop here with the rolling, now I will focus only on what I need, KT66/77/88/EL34. Others have to come and continue.

As a small recap, I was able to try on Eternity:
- input: 6SN7, 6F8G, 6SL7, 5692, 7N7, 6J5 (L63), 6C5, 6N7G
- output: KT66, KT77, KT88, KT150, EL3N, EL32, EL34, EL38, 6L6, 6V6
Now comes the best part, to listen to music and not my amplifier.


----------



## hpamdr

I promise I will try EL39 EL12spe and GU50 ... and many small tube in input..
This will not be done with artistic photo but will try to picture it anyway. I will also try to get better output measurement with my old e-mu tracker pre if i'm able to use it with windows 10 

But i will enjoy a bunch of track i've selected to try Eternity my headphones and different set of tubes.


----------



## SonicTrance

OctavianH said:


> Now comes the best part, to listen to music and not my amplifier.


This is what it's all about in the end! I'm glad you've found your preferred tubes!


----------



## UntilThen

OctavianH said:


> As a small recap, I was able to try on Eternity:
> - input: 6SN7, 6F8G, 6SL7, 5692, 7N7, 6J5 (L63), 6C5, 6N7G
> - output: KT66, KT77, KT88, KT150, EL3N, EL32, EL34, EL38, 6L6, 6V6
> Now comes the best part, to listen to music and not my amplifier.



All lovely tubes no doubt. Every owner of a tube amp will go through that journey of self discovery. Thanks for sharing. At the end of tube rolling comes the best part as you've said. Just enjoy the music.

After 5 years and many tube amps, I'm kind of over with rolling tubes but the best part of Odyssey is that I already know what certain power tubes will bring. More exciting will be the fact that I have dedicated slots for EL11 and I'm looking forward to alternating that with either 6SL7 or 6SN7. 

These few weeks I've been very content not to tube roll with Destiny and Oblivion and that pattern will soon settle in for Odyssey.


----------



## OctavianH

hpamdr said:


> I promise I will try EL39 EL12spe and GU50 ... and many small tube in input..
> This will not be done with artistic photo but will try to picture it anyway. I will also try to get better output measurement with my old e-mu tracker pre if i'm able to use it with windows 10
> 
> But i will enjoy a bunch of track i've selected to try Eternity my headphones and different set of tubes.



I think you will like EL39. I liked a lot EL32 and EL38, those are good but not for my musical tastes, where EL34 or KT77 are better. About GU50 I have no idea, that is the one I am mostly interested to read.

PS. My photos are made with a simple android phone, then just maybe a filter. That's it, nothing fancy.


----------



## UntilThen

Today I made the executive decision after consultation with Tomas that my amp front panel will be similar to the silver Citadel. What goes on top is Odyssey's unique look. I'm happy with that. With the visuals out of the way, I wait in anticipation for the arrival of Odyssey and to sample her sonics.

I too use a iPhone 11 Pro Max for all my pictures. Even the night shots. You'll get better pictures with Sony Alpha A7 III and a good lens but the humble iPhone will do for now.


----------



## OctavianH (May 20, 2021)

While reading this page from JAC Music my mind went to you @hpamdr when I reached this part:





So besides that you will be able to try these in Eternity, it seems that you can "hammer a nail in the wall with this tube". Seems a good advice for the pieces in your stock which do not measure properly. Then you'll need a Rembrandt to put on that nail. LOL

Edit: In my case, I was reading about the Tesla EL34, which I like a lot, and what they write is interesting.





Mine are the same, double halo getter, angled:


----------



## OctavianH

New picture of the latest mosque from Instanbul. I've become a fan of EL34.


----------



## UntilThen

There’s a lot to like about EL34. My first encounter with that tube was when I first listen with Blue Hawaii Se way back in 2016.


----------



## OctavianH

UntilThen said:


> There’s a lot to like about EL34. My first encounter with that tube was when I first listen with Blue Hawaii Se way back in 2016.



I never knew too much about EL34. I always heard it is a "mid centric" tube loved by several people. For me this was not enough to have an opinion. But on Eternity EL34 combines what I love on KT88 and KT66 and adds a little bit of liquid on it. This is for me the best combination. Of course I have always to remember that my taste is different than the majority. For example now I am listening to this track:


----------



## UntilThen

EL34 in Auris Nirvana is simply beautiful sounding. Smooth, relax and powerful.... all in the one sentence.


----------



## OctavianH (May 20, 2021)

UntilThen said:


> EL34 in Auris Nirvana is simply beautiful sounding. Smooth, relax and powerful.... all in the one sentence.


I never had the chance of listening to Auris Nirvana. But EL34 sounds perfect on Hearts on Fire.



I learned this song on Wacken Open Air camping area. I was trying to sleep with while some sweeds were listening to heavy metal at maximum at their tents. They were drinking all night and listening to this song on repeat. After half night of trying to sleep I said "I'll go talk with them" and finished drinking beer and listening to it. Now it is one of my favourite songs, they were right, one should not sleep while the hearts are on fire. Great memories, I love this song!


----------



## hpamdr

OctavianH said:


> While reading this page from JAC Music my mind went to you @hpamdr when I reached this part:
> 
> 
> 
> ...


Good buy ! 
Chase another pair of edicron or tronal or .... Tesla just give a lose look to the construction before auction.

If you like JAC Music publication, you can also give a look to EL50 tube ! EL39 is very close to EL50 but lasting more and is more effective at low voltage.


----------



## OctavianH (May 21, 2021)

hpamdr said:


> Good buy !
> Chase another pair of edicron or tronal or .... Tesla just give a lose look to the construction before auction.
> 
> If you like JAC Music publication, you can also give a look to EL50 tube ! EL39 is very close to EL50 but lasting more and is more effective at low voltage.


I read a little bit about EL34, more to understand the history behind my pair. On the Edicron website they mention some stock of late 70s:





Edit: EL50, ah no, that socket. I remained at no adapters/no top cap philosophy and I prepare to sell all my tubes in that category with 2 exceptions (one pair of EL32 and EL38).
Why I would need those when I have EL34? 

Edit2: There are tubes like 4699, seem like EL34 metal base with EL3N base type, what a nightmare:


----------



## hpamdr

OctavianH said:


> I read a little bit about EL34, more to understand the history behind my pair. On the Edicron website they mention some stock of late 70s:
> 
> 
> 
> ...


As you can see these are the oldest Tesla EL34 tube they branded... These are really the best of all the list 
The link was not to point out on EL50 but more to give you an idea of EL39...


----------



## whirlwind

OctavianH said:


> New picture of the latest mosque from Instanbul. I've become a fan of EL34.


Killer amp.....EL34 are my favorite tubes also....happy listening and enjoy


----------



## hpamdr (May 21, 2021)

Let's prepare a set for Eternity...
Power: Ultron EL34 _(Tesla same construction as @OctavianH Edicron)_
Input: 6s5s russian 6C5G.


----------



## UntilThen

For a history of EL34, this is a must read. From page 16 to 21, every EL34 aficionados must read these pages twice and memorize it. 

https://worldradiohistory.com/Archi...m-Tube-Valley/Vacuum-Tube-Valley-Issue-16.pdf


----------



## UntilThen

And another article on the difference between EL34, 6CA7 and KT77.

https://www.tubesforamps.com/el34-6ca7-kt77-differences


----------



## UntilThen

Now I'm also interested in KT88 as Odyssey is biased on it. This is again a must read from page 4 to 8.

https://worldradiohistory.com/Archi...-Vacuum-Tube-Valley/Vacuum-Tube-Valley-19.pdf

and on page 11... *Why NOS tubes are better*.


----------



## OctavianH (May 21, 2021)

Excellent resources. I will, in time, read them. Thank you @UntilThen


----------



## UntilThen

Another good source of information on KT88.
http://www.jacmusic.com/KT88/kt88.htm

Some weekend reading to do.


----------



## UntilThen

I'm sending my precious tubes to Tomas. This is the start of Odyssey coming home.   

All NOS NIB. Sail on. Sail safely to Sweden.  That's my Mullard GZ34 double D getters, 132 / 122mA, f33 / LIJ 1961 Bruxelles MAEDA.

and no I don't have cheaper tubes.


----------



## triod750

I will be there before Tomas and snatch them away. Nobody will know what happened,or how. Just sayin...


----------



## UntilThen

triod750 said:


> I will be there before Tomas and snatch them away. Nobody will know what happened,or how. Just sayin...



But you didn't know that I'm sending 2 Pit Bulls together with the parcel.... and Bcowen is escorting and he knows karate.


----------



## triod750

UntilThen said:


> But you didn't know that I'm sending 2 Pit Bulls together with the parcel.... and Bcowen is escorting and he knows karate.


My sloughi will eat those pit bulls for breakfast. They will never know what happened either. But Bcowen is scaring me, karate or not. I might give up the idea or just go for the pit bull breakfast.


----------



## UntilThen

Sloughi lol. Didn't know that breed until now.


----------



## triod750

UntilThen said:


> Sloughi lol. Didn't know that breed until now.


And the touaregs have had them for thousand years or more. I've seen black and white photos of a sloughi taking down a jackal in full speed. From first decade of the previous century. I get speed tickets for mine. 60+ km/h.


----------



## UntilThen

If I keep talking sloughi I will not pack the tubes in time and the Post Office will close in less than 2 hours time !


----------



## hpamdr (May 22, 2021)

UntilThen said:


> If I keep talking sloughi I will not pack the tubes in time and the Post Office will close in less than 2 hours time !


Do not rush.. The tubes have to cross half of earth flying over Ocean, Iraq, Turkey,  Romania/Ukraine,... 
_Edited -- I'm not sure Postage works great on Sunday. I'm always in the same situation sending end of week and letting parcel stay stationary for a day in sorting office..._


----------



## UntilThen

Tubes are sent off to Sweden. Chilling down playing Tangerine Dream 'Out of this world' LP and listening with LCD4. Destiny on duty.

Not too long now before Odyssey build begins. I look forward to using vinyl with Odyssey. Not a pop or crackle in my setup.


----------



## OctavianH

Now it is my time to chill. Yesterday I was off to beer garden, I took Friday Beerday seriously and went to celebrate it.
But this morning, waking up and listening to some Empire from Queensrÿche with EL34 makes my blood flow through my veins.
What an incredible tube is EL34, especially for rock...


----------



## OctavianH

UntilThen said:


> I'm sending my precious tubes to Tomas. This is the start of Odyssey coming home.
> 
> All NOS NIB. Sail on. Sail safely to Sweden.  That's my Mullard GZ34 double D getters, 132 / 122mA, f33 / LIJ 1961 Bruxelles MAEDA.
> 
> and no I don't have cheaper tubes.


Ah, we have stuff to do next week. Well, okay


----------



## OctavianH

Saturday morning. Hard choices. Eternity and EL34.





And EL34 at startup, bias set for 20mA when they stabilise.


----------



## OctavianH (May 22, 2021)

Ah, did anyone called for the Iron Maiden? No? Maybe it was all in my head then.






I always knew I have too many albums of this band (and this is just a part of them). But everytime I want Iron Maiden I choose Seventh Son of a Seventh Son.

And the OCD guy nightmare, to make again Eddie look right on your shelf. LOL





Today I'll have a lot of fun with Eternity. Let's hope I'll not search for Megadeth or Blind Guardian discographies otherwise I'll just arrange CDs on my shelf in the following month.


----------



## UntilThen

You sure have a lot of metal CDs


----------



## OctavianH (Nov 14, 2022)

Time for me to listen to Children of the Grave:



And yes, @UntilThen I have a big collection of metal CDs. I choose CDs because metal is sometimes underground, they do not have money to press vinyl. I had a huge tape collection but this is nowadays stored somewhere in my parents house. I took only my CDs with me when I left.


----------



## OctavianH

And I reached what I call the most extreme part of Black Sabbath. Here Ozzy screams and performs the most intense parts of its early career. Dirty Women was always a special track for me, it says so much about life, about me, about everyone. And the solo of Tony Iommi is absolutely killer, here EL34 takes its place to provide me the ultimate pleasure. Here is a live recording, but the album one is much better:



I love Ozzy, I love Tony, they changed my life.


----------



## OctavianH

I will not make this thread about music, I know I have already been off topic a lot. But I cannot help myself posting this.
Harakiri for the Sky are one of the best metal acts of today's scene. They are just killer. I love a lot their intense sound and emotional touch.
I watched this for hundreds of times, and I cannot stop it. This makes me feel alive.


----------



## OctavianH

What an incredible day guys, full of Black Sabbath and EL34. I think I'll try a good white beer because now I have time for it.





And now it is time for War Pigs. Eternity got some dust on it, most probably my wool carpets.


----------



## UntilThen

Octa, I'll be with you when I come home from the Sunday market. In the meantime rock on !


----------



## OctavianH (May 22, 2021)

I have moved from the rainy islands of UK to Portugal. Here Moonspell is ruling. The latest album is incredible, more progressive and melodic but still retaining their core.
EL34 is doing what it has to do, providing that natural sound of electric guitar, that beloved distorsion.


----------



## OctavianH

Returning to Germany, UDO is always the best. Being a huge Accept fan, I can only return to Germany with a good dark beer and this song.


----------



## triod750

OctavianH, you are wild and crazy - I enjoy your ride. Your waiting for this amp was worth it, wasn't it. You didn't come to Tomas empty handed - you were an educated customer.


----------



## OctavianH

triod750 said:


> OctavianH, you are wild and crazy - I enjoy your ride. Your waiting for this amp was worth it, wasn't it. You didn't come to Tomas empty handed - you were an educated customer.


Thank you for your kind words @triod750 I respect you a lot and you have a lot of experience, your words mean a lot to me. I am just a "kid" enjoying heavy metal.
I started with LittleDot MK2 and then moved to Elise. They were great amps for me, helping me to learn and understand more. Now Eternity is providing me a new journey.
I try to stay on topic, but I think a little bit of personal touch helps, so I try to show the person behind the journey, thinking that maybe this will help people to understand more of my personal opinions. We love our amps, our tubes but in the end we are normal persons, loving music. I love heavy metal, but I am just a normal person.


----------



## OctavianH

I cannot listen to UDO without going back to Accept songs. I know, he is great doing his own work but Accept is a part of his story.
And what can be better for a Saturday evening than Neon Nights?


----------



## OctavianH

And as an evening has to end, it cannot end without Manowar. This is what I expect from US. Pure madness.


----------



## OctavianH

After the marathon of the last 2 days I reached 50 hours on EL34 and they evolved a lot. In the beginning I was reporting that they sounded a little bit harsh to me. Now, after the burn in, they stabilised and do not have anymore that harshness I was complaining. However, they are sounding differently than my GEC KT77 which remain my favourite outputs. While KT77 are warm and liquid, these Tesla EL34 are more towards a neutral sound, somehow more natural. What I prefer? Honestly KT77, even if I know that the sound those are presenting is artificial. But for the price we are able to find these EL34, they are, for sure, winners in the price/performance category.





Ah, and I just observed that using the socket savers these are colder with around 5C. I just measured 106C compared to 111C I was measuring without them.
A very special and interesting tube, we are lucky to find it at decent prices and we should, of course, give it more attention because it is incredible.


----------



## hpamdr

Got a new Heddphone to pair with Eternity... Still on the way to home !
Listening Chris Jones_ (Great voice and guitar for Headphone Demo)_


----------



## OctavianH

hpamdr said:


> Got a new Heddphone to pair with Eternity... Still on the way to home !


I am very curious what you will say about them, I am still trying to get used with ZMF Verite Open which from time to time is too heavy for my taste, and these seem bigger and heavier. I've read recently this review.


----------



## UntilThen

hpamdr said:


> Got a new Heddphone to pair with Eternity... Still on the way to home !
> Listening Chris Jones_ (Great voice and guitar for Headphone Demo)_



What headphone did you get? He1000se and LCD4 is what I have and I don't need no more. These 2 headphones will pair very well with Odyssey. 

I have that Chris Jones album on audiophile CD but I prefer listening to Eva Cassidy on Roon/Tidal or on my 4 LPs Nightbird album.


----------



## hpamdr

UntilThen said:


> What headphone did you get? He1000se and LCD4 is what I have and I don't need no more. These 2 headphones will pair very well with Odyssey.
> 
> I have that Chris Jones album on audiophile CD but I prefer listening to Eva Cassidy on Roon/Tidal or on my 4 LPs Nightbird album.


It is an heddphone _(Demo Version)_ from Hedd Audio. This fit my mid-range listening preferences and my bull neck 
It is just not so easy to drive as it needs current oriented amplifier. It have same sensitivity and impedance than Abyss 1266.

I do not have any Tidal/Roon/... online collection never used LP since more than 30 Years.. Just CD/SACD  I rip or loseless files.  The only exception id BandCamp where i listen some new artist and download tracks...
What i like about Chris Jones Albums, is the great recording quality and some nice effect really fitting well with headphone listening.


----------



## UntilThen

My fav... Alan Taylor and Chris Jones on Tennessee Waltz. I had this on CD... from when I was into car audio comp.  




Also have this CD... some of the best female audiophile singers.


----------



## triod750

OctavianH said:


> We love our amps, our tubes but in the end we are normal persons, loving music. I love heavy metal, but I am just a normal person.


Absolutely, you are a normal person and so am I and a couple of others. Then we have the rest....


----------



## UntilThen

OctavianH said:


> We love our amps, our tubes but in the end we are normal persons, loving music. I love heavy metal, but I am just a normal person.



Nah you're all abnormal. I'm the only sane one here. Odyssey is as sane as can be. I think Tomas is putting in the first screw.


----------



## jonathan c

UntilThen said:


> Nah you're all abnormal. I'm the only sane one here. Odyssey is as sane as can be. I think Tomas is putting in the first screw.


Celine wrote: “tout le monde est ne fou, il y’en a quelque qui y reste” [ everyone is born crazy, some stay that way ]


----------



## OctavianH

I guess the sanity and its rules changed a lot recently. On Sunday I just found about this guy:



After I found that he is a "celebrity" and that those guys he talks about are real, I definitely regained some trust in my sanity. LOL


----------



## hpamdr

jonathan c said:


> Celine wrote: “tout le monde est ne fou, il y’en a quelque qui y reste” [ everyone is born crazy, some stay that way ]


In fact, the citation is from *Samuel Beckett *: 
"Nous naissons tous fous. Quelques uns le demeurent."
@OctavianH, Just Enjoy !


----------



## OctavianH

@hpamdr I think you can try your new Heddphone with the soundtrack of Domina.



I watched recently the first season, quite good. Now I enjoy the music. More about the fight for power and politics, than wars or conquests.

PS. Shocking isn't it, to see me recommending something which is not heavy metal. LOL


----------



## hpamdr

OctavianH said:


> I watched recently the first season, quite good. Now I enjoy the music. More about the fight for power and politics, than wars or conquests.
> 
> PS. Shocking isn't it, to see me recommending something which is not heavy metal. LOL


Nothing shocking, I like a lot Joanna Forbes. She was soprano in the "The Swingle Singers" a wonderfull a capella band for all kind of music.

(The last Metal CD i bought was Moonspell : the Butterfly FX) in previous century ...


----------



## OctavianH

When they released Sin/Pecado and Butterfly FX I was unsure about the direction they were taking. But all went well in the end.
I think you might like also this performance:



It is funny the comment:





I completely agree. Eternity and EL34 sound killer on these soft acoustic songs.


----------



## hpamdr

About the comment: What is present in this live recording and not on the CD version is a huge room reverb. It is pleasent to listen and add specific live soundstage effect. This was probably recorded in place with minimum acoustic treatment and not multi channels from mixing table ! 
For live in stadium with wall of amplifier, you have rolling/spining reverb which is specific to Arena. This make bootleg recording noisy and full of decay ...


----------



## OctavianH

Today I wanted to play a little bith with EL34 and T1.2 and realised that things are a little bit more complicated than expected.





Rolling a few pairs of inputs I realised that I could not obtain exactly what I wanted, in short terms a wider soundstage and a more agressive sound. EL34's forgiving nature, that fuller sound, is somehow too much for me combined with T1.2 similar nature, and the inputs have not enough power to change things in a radical way. If Verite Open sounded incredible with EL34 and almost all inputs, T1.2 needs something different. I liked it more with KT66 or KT88. But in the end, conclusions of today were very pleasing because I never wanted to own 2 similar headphones, I always wanted different signatures, to have more playground.

Eternity becomes addictive when you start to know it, because you will start to be able to predict changes. In my case with T1.2 it was hit and miss, but the game remained a pleasure. I will have to give more time to these headphones.


----------



## OctavianH

And indeed, with T1.2 we need to use different tubes. So I said to try an all brown setup, using 6SL7 as input. This tube is very easy to bias, in my case just putting the inputs at minimum which is my case is around -0.4V, this taking it to around 2.6mA. But one thing I have observed, is that the tube flashed at startup, then in 1 second just reduces the glow. I guess the problem is that it has a very low bias value, and my amp at strartup draws for one second a bigger amount of current, which I can see also on the VU meters as a slight jump. Everthing is almost instantaneous, but I hope I'll not damage my 6SL7 by giving it too much current at every startup.


----------



## SonicTrance

OctavianH said:


> And indeed, with T1.2 we need to use different tubes. So I said to try an all brown setup, using 6SL7 as input. This tube is very easy to bias, in my case just putting the inputs at minimum which is my case is around -0.4V, this taking it to around 2.6mA. But one thing I have observed, is that the tube flashed at startup, then in 1 second just reduces the glow. I guess the problem is that it has a very low bias value, and my amp at strartup draws for one second a bigger amount of current, which I can see also on the VU meters as a slight jump. Everthing is almost instantaneous, but I hope I'll not damage my 6SL7 by giving it too much current at every startup.


Some tubes have that flash at startup. There are different opinions on what it actually is. Some say it's a built in feature of the tube. Others that it's a sort of malfunction. I tend to believe it's some sort of malfunction. But, I've had several tubes that does this and never had an issue with them otherwise.


----------



## UntilThen

Beyer T1.2 must be experienced with an amp with power. Hearing it with my previous Sansui 907mr is a revelation.This late model Sansui has a more hifi tone as compared to older and warmer Sansuis like the 717. It's quite incredible that I sold off the T1.2 cheap. 

What 6SL7 did you have there Octa? 6SL7 will play a big part in Odyssey because of the higher gain. I'll also be experimenting with 12AT7 and 12AX7. If I wanted to dial back then I'll fall back on EL11, 6SN7 or 12au7. Going through my correspondence with Tomas, he told me that full power with KT88 can be achieved with all these drivers but with varying degrees of the volume knob turn.


----------



## OctavianH (May 25, 2021)

UntilThen said:


> What 6SL7 did you have there Octa? 6SL7 will play a big part in Odyssey because of the higher gain. I'll also be experimenting with 12AT7 and 12AX7. If I wanted to dial back then I'll fall back on EL11, 6SN7 or 12au7. Going through my correspondence with Tomas, he told me that full power with KT88 can be achieved with all these drivers but with varying degrees of the volume knob turn.



I do not know much about 6SL7, but I always wanted to try the Brimar CV1985 because I read about it in several places. I always liked neutral driver/inputs combined with warmer powers. So I bought one in the past. I like it, very neutral and transparent, a good tube to tame the KT88, and I am glad that you also mention about this combination.






But what I like more is the Fivre brown base 6C5G! Wow how nice are pairing these with GEC KT66 and T1.2. They have a quite big extension on high frequencies and are complemeting somehow the rest of the setup. Other tubes sound somehow "muffled" but these inputs are perfect.


----------



## UntilThen

I must chase down that Brimar CV1985. I have this red lettering Brimar 6SL7 and I have not heard it. In fact I have not heard any of the 6SL7 I bought except the pair of NOS NIB Tung Sol 126sl7gt black glass round plates that I use in GOTL.


----------



## UntilThen

How can I forget that Mullard ECC35 is also a 6SL7 type. Do you have this tube Octa? I going to buy another ECC35 again. Had this tube with GOTL !


----------



## OctavianH

UntilThen said:


> How can I forget that Mullard ECC35 is also a 6SL7 type. Do you have this tube Octa? I going to buy another ECC35 again. Had this tube with GOTL !



No. But I would like to have a pair or at least one Mullard ECC31. Anyway, judging by how good 6C5G/6J5G sound, I will never invest in them.
I started to sell my 6SN7/6AS7 collection, at the moment spare parts, to keep some tubes for 2045 when Tomas will build me the amplifier for Black Sabbath 75 anniversary.


----------



## UntilThen

Mullard ECC31 isn't the same as ECC35. Had both of them and much prefer ECC35. ECC33 is also very good.

I need Odyssey first to determine if I prefer using 6SN7 type or 6SL7 type. Difference in gain is huge.


----------



## OctavianH (May 25, 2021)

UntilThen said:


> Mullard ECC31 isn't the same as ECC35. Had both of them and much prefer ECC35. ECC33 is also very good.


Mullard ECC31 was a wish of mine during Elise days, but I never had the chance to try those. As far as I know they are similar with 6N7G (pinout) and should work natively in Eternity. Anyway I already have 3-4 pairs of 6C5/6J5 and also KT66/77/88 and EL34. I do not need anything else, honestly.


----------



## UntilThen

You keep talking about ECC31. I'm talking about ECC35. Try that and it will blow your 6J5 away. I'm willing to bet $5.


----------



## OctavianH

UntilThen said:


> You keep talking about ECC31. I'm talking about ECC35. Try that and it will blow your 6J5 away. I'm willing to bet $5.


I am convinced those are good, but I'll wait for you to discover more of their misteries on UltraSonic amps. 
By the way I need an additional filer on Ebay, "European Union - Italy" to get rid of these guys like this one:





Honestly, I am tired of seeing tubes sold in Italy at 10x the price of others.


----------



## UntilThen

Here I give you more of the Italians you love.  
https://www.ebay.com.au/itm/123939079244?hash=item1cdb58444c:g:L48AAOSwhvpdpBMH

I hope I don't go nuts with 6SL7 because there are many good ones. 

However I still have to buy at least one 5U4G rectifier. This one's nice but what a price tag.
https://www.ebay.com.au/itm/264961008822?hash=item3db0e824b6:g:n-gAAOSw~nFfx3oZ


----------



## OctavianH (May 25, 2021)

Yes, let me give you an example of patience: Fivre 6N7G. I searched for long for these, and in the end I found them.





I bought a pair from Germany, unopened and untested for 31 EUR. I took a risk, they work perfectly. I put some time ago pictures with those on Eternity.
Now, let's search for a pair of these:





Interesting, isn't it? I am not saying one should find these at 31.5 EUR, but I would say a fair price would be up to 100 EUR / pair. Those are good, I like them, make sense.
But what these guys sell is crazy and Ebay is flooded by them.

If I'll find some good ECC35 you like at this price I'll try them.


----------



## UntilThen

I'll make you my tubes purchaser.


----------



## hpamdr

About 6SL7 in non aristocratic area, you can get a russian equivalent 6n9s. The best ones are the Meltz metal base from the 50's _(you can find some for decent price from time to time just have to be patient)._ If you want to go with adapter, you also have 6sc7 which you can strap as single triode adapted to 6j5 (or directly to 6SL7 adapter pin3/1 but with common cathode).
I personally plan to use 12SL7 tungsol and fivre with Eternity if it land.......


----------



## OctavianH

UntilThen said:


> I'll make you my tubes purchaser.


Even if my job in the latest years has become less and less engaging (to be polite), to be a tube purchaser for all your current and future amplifiers is a very big hat. I do not have courage to engage in something like this and I strongly think it is one of the most difficult positions one can be hired on. But I can make a recommendation:





This guy seems to have some vision, it might be a good tube purchaser between his other activities


----------



## OctavianH

hpamdr said:


> About 6SL7 in non aristocratic area, you can get a russian equivalent 6n9s. The best ones are the Meltz metal base from the 50's _(you can find some for decent price from time to time just have to be patient)._ If you want to go with adapter, you also have 6sc7 which you can strap as single triode adapted to 6j5 (or directly to 6SL7 adapter pin3/1 but with common cathode).
> I personally plan to use 12SL7 tungsol and fivre with Eternity if it land.......



Yes, I plan to try a pair of:






with a:





But I will do this later, first I have to use what I have and to drag some conclusions. There is no hurry even if I have to admit I am quite curious about those "coin based" tubes and their glow.


----------



## UntilThen

No worries Octa. I have employed Bcowen. He comes highly recommended. Great knowledge in tubes.


----------



## hpamdr

OctavianH said:


> Yes, I plan to try a pair of:
> 
> 
> 
> with a:


If you are lucky, you can get special (1540) 6p3s-e from 60's which sound better..


----------



## UntilThen

Odyssey will have a drivers selector switch now. Back panel will look as good as the front. 😋


----------



## hpamdr (May 27, 2021)

UntilThen said:


> Odyssey will have a drivers selector switch now. Back panel will look as good as the front. 😋


Do you mean socket selector (EL11 / ECC35 ) or driver voltage or .. selector ?
Will you ask to have headphone plug on the top to have same L&F as Destiny ?


----------



## UntilThen

hpamdr said:


> Do you mean socket selector (EL11 / ECC35 ) or driver voltage or .. selector ?



Selector switch for either EL11 or 6SL7 or together. So 3 positions rotary knob. 

Back panel will have:-

Two rotary switches:
Input RCA select
Input tube select

One toggle switch:
Triode or Ultralinear operation.

Rotary switches similar in appearance to the front 2 rotary switches.



hpamdr said:


> Will you ask to have headphone plug on the top to have same L&F as Destiny ?



No way


----------



## OctavianH

UntilThen said:


> Selector switch for either EL11 or 6SL7 or together. So 3 positions rotary knob.
> 
> Back panel will have:-
> 
> ...



This means you will need to allow enough space and visibility of the back panel in order to operate it correctly. In my case I have 3 on/off switches and I can easily change them without looking directly, being placed and wired wise, but in your case it might be different.


----------



## hpamdr (May 27, 2021)

UntilThen said:


> Selector switch for either EL11 or 6SL7 or together. So 3 positions rotary knob.


Do you plan to use both at same time ?
if Yes, EL11 is not really compatible with 6SL7 so you should be very careful and Ask @SonicTrance about what should and what should not be done...
I have in my CTH broken some tube with dual // adapter... my curent statement is to never mix driver/output tube anymore !


----------



## UntilThen

Easy I can operate switches with my eyes closed.  I have a foot and a half of space behind rack. Input tube switch cannot be operated when amp is on.


----------



## UntilThen

hpamdr said:


> Do you plan to use both at same time ?
> if Yes, EL11 is not really compatible with 6SL7 so you should be very careful and Ask @SonicTrance about what should and what should not be done...



Tomas don't see a problem with both tube types operating together but I probably won't after trying it out. It will only add more distortions according to Yoda.


----------



## UntilThen

The only thing I resisted adding is preamp out as I can't see how I will use Odyssey as a preamp.

For lesser gain, I'll use EL11 or 6SN7 or 12au7. For more gain, I'll use 6SL7 or 12at7 or 12ax7. That should be enough variations.


----------



## SonicTrance

UntilThen said:


> The only thing I resisted adding is preamp out as I can't see how I will use Odyssey as a preamp.
> 
> For lesser gain, I'll use EL11 or 6SN7 or 12au7. For more gain, I'll use 6SL7 or 12at7 or 12ax7. That should be enough variations.


I will say though that I'll use feedback in Odyssey to tame the KT88's some. So, the difference in gain between say 6SN7 and 6SL7 won't be as huge as the numbers might say, mu 20 vs 70. There'll still be a difference of course.


----------



## UntilThen

Taking stock of my tubes before Odyssey's arrival.

Drivers
GE 5691 x 2
Tung Sol 6SU7gty
Brimar 6SL7
Ken Rad 6sn7gt black glass
Tung Sol 6F8G x 2
Sylvania 6sn7gtb
RCA 6sn7gt smoke glass
Raytheon 6sn7gt black glass
Brimar 12au7 long plates
Mullard 6201 / 12at7
Telefunken EL11
Siemens EL11

Powers
GEC KT66
Tung Sol 6550 1960s
Philips Miniwatt 6CA7 double O getters
RFT EL34 single O getter
Radiotron 807
Sylvania 807
La Radiotechnique EL39
Telefunken EL12 spez
Tesla EL12 spez
Genalex Gold Lion KT88
Psvane KT88 Tii classic
Shugang KT88 50 years treasures
Genalex Gold Lion KT77
EH 6L6GC

Rectifiers
Mullard GZ34
Sittard GZ34
Mullard GZ32 x 2
Cossor 53ku


----------



## UntilThen

Not enough! Need to get more aristocratic tubes.


----------



## hpamdr

As I'm waiting for an Eternity...
Just rediscovered a nice recording with Heddphone (Euforia with EL39 + 6j49p gold pin selected for Eternity) :



As said i have a bull neck so heddphonne can be used for long time  The slap and the sweep of the Drums, the low frequencies and the "attack" of the organ and the pitch of the guitar are really great with this combo.


----------



## OctavianH (May 28, 2021)

hpamdr said:


> As I'm waiting for an Eternity...


So you are still waiting. 

By the way guys, let's not forget that there are 2 nice things to roll, tubes and...






Friday Beerday!


----------



## SonicTrance

OctavianH said:


> So you are still waiting.
> 
> By the way guys, let's not forget that there are 2 nice things to roll, tubes and...
> 
> ...


I have to wait a few more hours for beerday, unfortunately. Working afternoon shift is a pain. Especially on fridays lol.


----------



## OctavianH (May 28, 2021)

SonicTrance said:


> I have to wait a few more hours for beerday, unfortunately. Working afternoon shift is a pain. Especially on fridays lol.


I know, I would summarize it "working is a pain". LOL
Here it rains for 2 days already, so nothing better to do than some EL34, reading and a good beer.





After several days of playing with both T1.2 and VO I could not find a combo which will make T1.2 get close to VO with EL34 and L63. The synergy between them is incredible, especially for rock music. So T1.2 went on the shelf and VO remained here.


----------



## SonicTrance

OctavianH said:


> I know, I would summarize it "working is a pain". LOL
> Here it rains for 2 days already, so nothing better to do than some EL34, reading and a good beer.
> 
> 
> ...


Nice! At least the weather i good here, 15C and sunny! 🌞

Did someone ever make an ST shape EL34? Would be sweet. I like ST bottles


----------



## OctavianH (May 28, 2021)

SonicTrance said:


> Did someone ever make an ST shape EL34? Would be sweet. I like ST bottles


Nope, only straight glass. No problem, I love them regardless of the shape. Butterfly's "Doorways of Time" sounds incredible. 
Listening to this album with EL34 and VO is an experience. Very clean and tight production, and that guitar...


----------



## OctavianH (May 28, 2021)

Eternity is incredible, EL34 makes me think I'll never want something else. There is only one thing I am missing, Tung Sol 5998.
Here were half of my each pair of "domino" tubes. I have sold the left one, O-getter, but I still have the rest and I will keep them for a future OTL.





On the one with white print, second from left, I have around 3000-4000 hours. I never heard any difference between the three ones from left. But WE 421A is another animal, a very special tube for me. It will come a time when these will power another OTL and that one will have a rectifier: WE 422A. I have no idea when, but it will happen. It will have 2 x 5998, 2 x 6SN7 and one rectifier. Sounds good?

PS. I think these are the most beautiful tubes ever made. At least for me.


----------



## SonicTrance

The 5998's are very good tubes. I still have a few myself. I did build an Eternity type circuit using the 5998's in the past but it was noisy. Then I tried the 421A's in the same amp, dead quiet! 



OctavianH said:


> It will have 2 x 5998, 2 x 6SN7 and one rectifier. Sounds good?


Definitely doable! =)


----------



## OctavianH

SonicTrance said:


> The 5998's are very good tubes. I still have a few myself. I did build an Eternity type circuit using the 5998's in the past but it was noisy. Then I tried the 421A's in the same amp, dead quiet!


I would say you keep them, they seem to become hard to find recently. I was not thinking about a modern design for these, more a classic one, but first, let's see what Odyssey can do and then we will see.


----------



## OctavianH (May 29, 2021)

By the way guys, in my quest of searching for the best EL34 I found about this guy:



Not sure if these are Mullards or RFTs but they sing nice. It's incredible what Google Search can do. LOL


----------



## UntilThen

OctavianH said:


> I would say you keep them, they seem to become hard to find recently. I was not thinking about a modern design for these, more a classic one, but first, let's see what Odyssey can do and then we will see.


Odyssey can do everything.


----------



## OctavianH

Too much silence on the Western Front.


----------



## triod750

The Empyrean Quintet!


----------



## UntilThen

OctavianH said:


> Too much silence on the Western Front.



That's because I'm on the Eastern Front with the 6SN7 thread.


----------



## OctavianH

I found yesterday a pair of RFT EL34s at 28 EUR (used, measuring over 90%). I had to take them, after all I am quite curious to see where the new production tubes (90s) is situating compared to my Tesla EL34. Rebranded as Siemens, "94A04", I think these were manufactured by RFT. But were they still producing these in the 90s? Well, we'll see.


----------



## hpamdr (Jun 1, 2021)

Today experiment :
Output: 6p6s (6V6 equivalent) bias -16V
Input: 6Ж49П-ДР (ugly in house adapter, bias - 3V)
The input is probably stressed a bit, but it sound really great !

Output tubes are not as dynamic as GU50 but gives a good result for close on air recording (Ancient music, Jazz, Pop where you can feel the air around microphones). GU50 are still my preferred tube for drums, organ and piano.... every good recording.




Pairing with HD800S, Heddphone,...K701 but T1 pair much better with Euphoria ???
_// i also got a new pair of EL34 double OO getter, genuine Tesla yellow marking mesure above 100% but not in box ... (next test for today afternoon) _


----------



## OctavianH

hpamdr said:


> Pairing with HD800S, Heddphone,...K701 but T1 pair much better with Euphoria ???


I wanted to ask you how you feel about T1 and Eternity but in the end I decided to wait for you to say something. I spent 2 days with T1 trying to find a good combo and honestly, I was not able to obtain what I wanted. VO with EL34 and L63 are miles away. If I remember correctly, T1 sounded better on Elise, do you have the same feeling? The best I obtained for T1 was KT66/KT88 with some clean neutral input as Brimar 6SL7GT CV1985, Fivre 6C5 or some very neutral towards SS 6SN7 like Psvane CV181T2. I know that in the beginning I was quite fascinated about T1, but I guess it was more related to Eternity's capabilities and resolution/dynamics than the headphone itself, after I heard VO with EL34 I realised T1 was under my expectations.


----------



## hpamdr

OctavianH said:


> I wanted to ask you how you feel about T1 and Eternity but in the end I decided to wait for you to say something. I spent 2 days with T1 trying to find a good combo and honestly, I was not able to obtain what I wanted. VO with EL34 and L63 are miles away. If I remember correctly, T1 sounded better on Elise, do you have the same feeling? The best I obtained for T1 was KT66/KT88 with some clean neutral input as Brimar 6SL7GT CV1985, Fivre 6C5 or some very neutral towards SS 6SN7 like Psvane CV181T2. I know that in the beginning I was quite fascinated about T1, but I guess it was more related to Eternity's capabilities and resolution/dynamics than the headphone itself, after I heard VO with EL34 I realised T1 was under my expectations.


My feeling about T1 is that it is far from HD800s/Heddphone in terms of precision for low frequencies. Even if it sound great it seems that the warmer sound of Eudora match better T1 and comparing with other headphone it seems a bit veiled on Eternity.


----------



## hpamdr

Test for this afternoon:
input : 6J5 (KR VT94 bias -7V)
output: Tesla EL34 bias -16V




The synergy between EL34 and 6J5 is really great and better than with 12SL7 witch make sound not as clean. 

Sound is clean, well articulated with warm flavor.  This is not as dynamic as GU50 but it is a bit more tubey.  (The slap of the bass does not kick, but vibrate a bit more)
This combo is great with many pop, blues and classical music. 
This combo is also a good match with HD650 and Heddphone ! _(did not try all the headphone around)_


----------



## OctavianH

Exactly, and if you add some GEC L63 to the table which are also bold and rich in tone, you get a quite tubey thick sound without harshness, bold, clean, as you say articulated and precise. This is definitely my endgame, EL34 and L63 (6J5). Incredible synergy with Verite Open and I foresee some good synergy with Auteur based on what I know about those, but for this we will need to wait until somebody tries it. I cannot get enough of EL34.


----------



## UntilThen

From my time with Elekit TU-8200, I find the core power tubes sounding brilliant. Genalex KT88, Philips Miniwatts 6CA7, RFT EL34, GEC KT66, Genalex KT77, EH 6L6GC. With 2 exceptions, EL12 spez and Radiotron and Sylvania 807. These are very good too. Drivers I use are the Brimar 12au7 long plates.


----------



## OctavianH

It's Friday and @hpamdr is not telling us anything about his new beautiful amp. No problem, I will tell you that I have not rolled anything in the last week. EL34 is perfect for me in output position. I just listen to the amp daily and read Pasquale Russo's Guide to EL34.


----------



## UntilThen

Hpamdr is probably too busy enjoying his amp to post any impressions.   Since you like EL34 so much, perhaps it's time to remove the socket savers and just leave them in the base sockets permanently.

What about the GEC KT66 though? Do you not like them just as much as or do you prefer the EL34 now?

I'm waiting on Odyssey and also on my Elekit TU-8200 to be restored. So I've no amps to roll in my KT88, KT77, KT66, 6550 and EL34... and EL39, 807 and El12 spez. So many tubes waiting to have a go.

So I just spend time with Destiny and Oblivion instead. Fortunately they are great amps with my headphones and I ain't complaining too much.


----------



## OctavianH

UntilThen said:


> What about the GEC KT66 though? Do you not like them just as much as or do you prefer the EL34 now?


I like KT66 more with T1.2 but the headphone fails behind Verite Open in certain aspects. For Verite Open I definitely prefer EL34.
However, I will keep them with the socket savers because the grip was too tight on the amplifier sockets and I am afraid to damage something.


----------



## UntilThen

OctavianH said:


> I like KT66 more with T1.2 but the headphone fails behind Verite Open in certain aspects. For Verite Open I definitely prefer EL34.
> However, I will keep them with the socket savers because the grip was too tight on the amplifier sockets and I am afraid to damage something.



I see you have fat pins on your EL34. When Destiny was new, the sockets were very tight too. Almost broke into sweats first time I try to remove the drivers.  For the last 3 weeks, I did not change tubes. Not that there's any tubes to change on the 300b amp except maybe the rectifier, which does not affect the tone much. GZ34 is the best rectifier to use in there. I suspect it will be the same for Odyssey. Although Tomas told me to use 5U4G for EL39 and EL12 spez.


----------



## OctavianH

I have no idea why those pins are like that, it is the first time for me to see a difference between tubes, I thought it was a standard. But I prefer to let those in the socket savers instead of forcing my sockets.


----------



## OctavianH (Jun 5, 2021)

Summer time is a good time to return to T1.2. The reason is that Verite Open in summer becomes, at least for me, more uncomfortable. When the temperature raises in the room I start to feel more and more its weight and those leather pads start to annoy me. Putting T1.2 on the head is like a breath of fresh air, but now comes the challenge to make this one sound decently on Eternity.





And the 1M $ questions remains: What high end headphone might provide me the sound quality of VO with the comfort and durability of T1.2?

I looked a little bit at Kennerton Thekk which has around 390g and seems reliable enough. But I am not sure I'll ever want a wooden headphone again, too sensible in my opinion. I never cared about the looks of a headphone, I am not seeing it when using it, I just want to forget it is there and be able to enjoy my music. And when I work or forget to pay attention and it fails on the floor I want to be more worried about the floor than the headphone. This happened with T1.2 which honestly is quite indestructible, it fell several times on the floor and nothing happened. Well, my future headphone will be in the same category if I'll ever buy another one.

PS. I like more T1 with the Impedance on High-Z than on Low-Z even if the volume is not a problem, with High-Z I keep it around 1PM and with Low-Z around 3PM. But the High-Z position is slightly warmer and on some passages has less harshness. Or maybe I am just crazy and hear what my brain tells me to hear.

PS2. My second double EL3N -> 6SN7 adapter broke after I've used it 2 times. So think twice before you buy that from Ebay.


----------



## SonicTrance

OctavianH said:


> PS. I like more T1 with the Impedance on High-Z than on Low-Z even if the volume is not a problem, with High-Z I keep it around 1PM and with Low-Z around 3PM. But the High-Z position is slightly warmer and on some passages has less harshness. Or maybe I am just crazy and hear what my brain tells me to hear.


Impedance matching can be important. What's the impedance on the T1's? 300? 600? 
What the impedance switch does is changing the turns ratio of the OT to get higher output impedance. This creates more distortion but also more power into high impedance headphones.
There's no right or wrong setting on the switch. The right setting is what sounds best to you 🙂


----------



## OctavianH

SonicTrance said:


> Impedance matching can be important. What's the impedance on the T1's? 300? 600?
> What the impedance switch does is changing the turns ratio of the OT to get higher output impedance. This creates more distortion but also more power into high impedance headphones.
> There's no right or wrong setting on the switch. The right setting is what sounds best to you 🙂


T1.2 has 600 Ohm. For me it sounds better on High-Z and maybe the "more power" effect is helping even if it creates as you say more distortion.


----------



## SonicTrance

At 600 ohms it won't create much more distortion. It's mostly at lower impedances the distortion increases with higher Z output. 
It makes sense you like the high Z setting better with those headphones.


----------



## OctavianH

SonicTrance said:


> At 600 ohms it won't create much more distortion. It's mostly at lower impedances the distortion increases with higher Z output.
> It makes sense you like the high Z setting better with those headphones.


Yes and I found the ultimate playground. Tubes with different gain levels combined with different positions of the impedance switch! This is something new for me, honestly I never had the chance to do this on my previous amplifiers. Being a total noob I always associated the gain switch with the volume knob and when I wanted to order Eternity I was planning to remove it from the build, what a mistake! Thank you that you stopped me doing this. 

I try now some 6SL7GT with KT66 and the High-Z setting and it is quite interesting. Volume knob went to 11PM but it is not about the volume position, the timbre and signature has some slight changes which I like. It might be that the impedance switch on UltraSonic amplifier will make T1.2 and other high impedance headphones sound better. I never observed this with Verite Open which has 300 Ohm. On that one both impedance settings were for me the same, just different volume.





I would be curious to try Eternity with some low impedance headphones, 32 Ohm for example, but I do not have any.


----------



## OctavianH (Jun 6, 2021)

Today I had a full day of Eternity. I had to work and spend my time near my PC which is also my source for music. So I had also time for Eternity. As usual, I started with new music, more extreme genres and later I returned to roots and listenend to some of my all time favourites. I think this is the way everyone does. A highlight of the morning was the new Typhonian EP which honestly can stand near the "gods" of the genre. An incredible effort. Later I moved to more progressive areas with the new Dordeduh album. Both these are on my short list of buying physical CDs. But later I returned to old school stuff, and Accept is always something without age for me. UDO is incredible.






But what is most important today is that Dark Tranquillity, one of my most loved bands, took the Swedish Grammys (metal section)!


----------



## triod750

OctavianH said:


> Today I had a full day of Eternity. I had to work and spend my time near my PC which is also my source for music. So I had also time for Eternity. As usual, I started with new music, more extreme genres and later I returned to roots and listenend to some of my all time favourites. I think this is the way everyone does. A highlight of the morning was the new Typhonian EP which honestly can stand near the "gods" of the genre. An incredible effort. Later I moved to more progressive areas with the new Dordeduh album. Both these are on my short list of buying physical CDs. But later I returned to old school stuff, and Accept is always something without age for me. UDO is incredible.
> 
> 
> 
> ...



And I didn't even know that they exist. Which country did you say they come from?


----------



## UntilThen

OctavianH said:


> Today I had a full day of Eternity



That sounds like a never ending day.  My fav listening cave.


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## OctavianH (Jun 6, 2021)

triod750 said:


> And I didn't even know that they exist. Which country did you say they come from?


Ah, do not worry, 99.9% of the world's population does not know about them.



UntilThen said:


> That sounds like a never ending day.  My fav listening cave.


In 2019 I would have said "nice amps" but in 2021 I have to say "nice video card". Most probably due to current cryptomining and shortages that one is the most expenssive one from the picture. LOL

By the way, after watching a few episodes from Netflix "Sweet Tooth" I have decided to stop complaining about headphones and comfort. I only think what earcups and headband would fit this kid:


----------



## UntilThen

OctavianH said:


> but in 2021 I have to say "nice video card"


What's your idea of a nice video card? I'm not a serious gamer so a 2070 super is sufficient for me. My custom PC is not even one year old but it's like yesterday's news.   I'm ok with it though. It's got enough grunt to do anything I want. Most of all it's my interface to my music. It's my Roon core. I can read news, participate on Head-Fi, listen to Youtube Premium if I want. The RGB has lost it's shine but it doesn't bother me. It's still quiet and that case... just love it.  

My PC configuration

AMD Ryzen 7 3800X CPU 8 Core 3.9GHz (Boost 4.5GHz) AM4, 105W TDP, 3Yrs Wty - Inc. AMD Wraith Prism RGB Cooler
AMD AM4 Ryzen Gigabyte X570 AORUS ELITE WIFI AMD AM4 ATX Motherboard
DDR4 3600MHz 16GB (4x8GB) Corsair Vengeance RGB Pro [CMW16GX4M2Z3600C18] 
2000GB Seagate ST2000DM008 Barracuda 7200rpm SATA3 HDD
Gigabyte 1TB Aorus M.2 PCIe NVMe Gen 4 SSD
M.2 Crucial 500GB P2 NVME SSD
DEEPCOOL PEC300 Riser Cable 
Gigabyte GeForce RTX 2070 Super 8GB Windforce Video Card [GV-N207SWF3-OC-8GD] 
MS Windows 10 Home 64-Bit Operating System DVD OEM
750W Deepcool DQ750-M-V2L 80 PLUS Gold Fully Modular Power Supply Black
NZXT H710i Smart Tempered Glass Mid-Tower E-ATX Case - Matte Black 
Case Fan 140mm NZXT AER RGB Black x 3 
CPU Cooler Corsair iCUE H115i RGB Pro XT (CW-9060044-WW), 280mm Radiator, Dual 140mm PWM Fans, Software Control 

Acer Predator X34P monitor


----------



## OctavianH (Jun 6, 2021)

UntilThen said:


> My PC configuration
> 
> AMD Ryzen 7 3800X CPU 8 Core 3.9GHz (Boost 4.5GHz) AM4, 105W TDP, 3Yrs Wty - Inc. AMD Wraith Prism RGB Cooler
> AMD AM4 Ryzen Gigabyte X570 AORUS ELITE WIFI AMD AM4 ATX Motherboard
> ...


Your PC looks very close to mine, except that I have 3900X with 4 more cores but your video card is a little bit better. I have 1080Ti and you have 2070. Ah, and I have double RAM. Well, I would like to upgrade to at least RTX 3080 but since they sell at around 2000 EUR I will definitely wait to 2023 to let these miners do their stuff. PC components are some of the worst investments. I would say you do not touch your PC because it is still fine.

PS. Something is wrong on your description, you cannot have 16GB ram (4x8)


----------



## UntilThen

Is this seller on crack? Selling Acer Predator x34p for $3031. https://www.amazon.com.au/dp/B079FV...l-22&linkCode=osi&th=1&psc=1&m=A3BJGXDIUWURPI

I only paid $1100 for mine.


----------



## UntilThen

OctavianH said:


> Your PC looks very close to mine, except that I have 3900X with 4 more cores but your video card is a little bit better. I have 1080Ti and you have 2070. Ah, and I have double RAM. Well, I would like to upgrade to at least RTX 3080 but since they sell at around 2000 EUR I will definitely wait to 2023 to let these miners do their stuff. PC components are some of the worst investments. I would say you do not touch your PC because it is still fine.
> 
> PS. Something is wrong on your description, you cannot have 16GB ram (4x8)



Don't worry I won't touch my PC. It will last another 7 years.   

Yes I bought another 2 x 8gb a week later. So I have 32gb ram now but for what I need it for 16gb would be plenty.


----------



## UntilThen

There's the 4 x 8gb of ram because I want more RGB then.


----------



## OctavianH

UntilThen said:


> There's the 4 x 8gb of ram because I want more RGB then.


It looks good. In my case I do not care about RGB. It's just a black box under my desk and from time to time I have to clean it from dust.

By the way, I might have a good deal on a pair of LCD-3. I have to be strong to resist it.


----------



## OctavianH

UntilThen said:


> Is this seller on crack? Selling Acer Predator x34p for $3031. https://www.amazon.com.au/dp/B079FV...l-22&linkCode=osi&th=1&psc=1&m=A3BJGXDIUWURPI
> 
> I only paid $1100 for mine.



If that one is on crack, check this out:





As I said, 2021 means "nice video card". I have a similar Acer Predator, but a smaller version than you, 27" (2560x1440) and my 1080Ti barely handles in in games like Cyberpunk 2077, so no new monitor for me before I'll secure an RTX 3080/3080Ti/3090. Or I'll just stop thinking and play older games. For example Valhalla, where I have to conquer England and then bring back Langrex in EU to avoid additional VAT when ordering tubes. The conqueror of tubes.


----------



## triod750

OctavianH said:


> Ah, do not worry, 99.9% of the world's population does not know about them.


I think you forgot a 9 there; 99,99%...


----------



## OctavianH

Still on my quest of finding a good combination for my T1.2.


----------



## triod750

Is that Fivre 6C5G? And 6SL7? Eternity Quintet?


----------



## OctavianH

triod750 said:


> Is that Fivre 6C5G? And 6SL7? Eternity Quintet?


Yes, it is the Fivre 6C5G brown base, sold by Langrex here. In the middle it is a Philips 6SN7WGTA. But it is only for "glow" purposes, I use only 2 x single triodes or 1 x double triode at the same time. At the moment I have selected Single Triode on the input switch so the one in the middle has the plate and grid unconnected. It lights and looks like I have 3 inputs but in truth, only 2 of them are used now. I know my pictures are misleading, one might think I use all 3 since all 3 glow. I have tried yesterday some 6SL7.


----------



## triod750

So it is a quartet with two pentodes and two triodes and no trumpet then. You know the trumpet is made from Metal, don't you? 

Is it safe for the longevity of a tube to run the heaters for more than pre-heating? I have heard or read something on that topic but don't remember the details. I suppose that you only do it for the photo?

Another question; This Fivre 6C5G - is it really a mesh anode or is the mesh part som kind of screen as they often are, whatever people call them?


----------



## OctavianH

triod750 said:


> So it is a quartet with two pentodes and two triodes and no trumpet then. You know the trumpet is made from Metal, don't you?


If the trumpet is made from Metal, it is fine in by book, however, the guitar is made from wood and remains my favourite.


triod750 said:


> Is it safe for the longevity of a tube to run the heaters for more than pre-heating? I have heard or read something on that topic but don't remember the details. I suppose that you only do it for the photo?


Tomas told me that normally the tube should not be damaged. I asked this when we discussed about this feature of having all tube sockets populated at the same time and glowing. However, I never keep for long amounts of time expensive tubes in the slots I am not using for listening. I have some tubes which are not measuring properly or were very cheap and I just use them for display purposes.


triod750 said:


> Another question; This Fivre 6C5G - is it really a mesh anode or is the mesh part som kind of screen as they often are, whatever people call them?


On the website of the seller it is marketed as "mesh anode" but this does not make me fully convinced it is not only a screen. Now the tubes are on the amplifier and I am not able to make a picture and try to look inside to see more. I do not have other pair to inspect, but when I will remove them I will try to check what can be seen inside the glass and maybe I will understand more. If not I'll just make a picture in proper light and post it here so maybe somebody else can take a look.


----------



## OctavianH

I was able to make some detailed pictures for the Fivre 6C5G "mesh anode".


----------



## triod750

OctavianH said:


> If the trumpet is made from Metal, it is fine in by book, however, the guitar is made from wood and remains my favourite.


The guitar is a wonderful instrument, whether acoustical or electric, as are all string instruments - not least the piano. Horns have to be played very well for me to enjoy them. Has to be the Metal part, I think.


OctavianH said:


> Tomas told me that normally the tube should not be damaged. I asked this when we discussed about this feature of having all tube sockets populated at the same time and glowing. However, I never keep for long amounts of time expensive tubes in the slots I am not using for listening. I have some tubes which are not measuring properly or were very cheap and I just use them for display purposes


Better safe than sorry then. Good move. I have a manual pre-heating mode on my main amp with the use of a separate button and I take care not to pre-heat it more than a few minutes before giving full throttle. I was advised to follow that practise.



OctavianH said:


> On the website of the seller it is marketed as "mesh anode" but this does not make me fully convinced it is not only a screen. Now the tubes are on the amplifier and I am not able to make a picture and try to look inside to see more. I do not have other pair to inspect, but when I will remove them I will try to check what can be seen inside the glass and maybe I will understand more. If not I'll just make a picture in proper light and post it here so maybe somebody else can take a look


I followed your link to the seller but wasn't fully convinced either. I would appreciate if you could smash one bottle and take high quality photos of the innards and then explain to me what I see .


----------



## triod750

OctavianH said:


> I was able to make some detailed pictures for the Fivre 6C5G "mesh anode".


You posted this while I was writing my post. I forgive you for not smashing the bottle 'cause you didn't know by then. Good photos!!  The anode must be the grey metal thingy inside the mesh screen, don't you think? If I will learn a lot more I will still be miles away from being an expert. I am pretty good at asking questions but worthless att answering them. Make no mistakes about that. My most important knowledge is that I know that I don't know that much.


----------



## OctavianH

triod750 said:


> You posted this while I was writing my post. I forgive you for not smashing the bottle 'cause you didn't know by then. Good photos!!  The anode must be the grey metal thingy inside the mesh screen, don't you think? If I will learn a lot more I will still be miles away from being an expert. I am pretty good at asking questions but worthless att answering them. Make no mistakes about that. My most important knowledge is that I know that I don't know that much.


I am not experienced and never really cared about tube construction, except the cases when I wanted to identify properly one to avoid buying a fake. From what I see here looking at the connections, the anode has to be the grey metal plate, inside we can see the grid and in the middle it has to be the cathode. However, this "mesh" (even if the word mesh means something else for me, this is not knitted) is connected to one of the pins and also connected inside:


----------



## triod750

OctavianH said:


> I am not experienced and never really cared about tube construction, except the cases when I wanted to identify properly one to avoid buying a fake. From what I see here looking at the connections, the anode has to be the grey metal plate, inside we can see the grid and in the middle it has to be the cathode. However, this "mesh" (even if the word mesh means something else for me, this is not knitted) is connected to one of the pins and also connected inside:



Well, yes, the nomenclature is diffuse to me but I agree that it is no mesh and not the anode but possibly some kind of 'screen' or 'shield' or what you call it. I am not fond of sellers using diffuse descriptions but I enjoy the A2293 tubes I bought from him. You often read about 'mesh anodes' but I don't think that they are very common either as mesh or anodes.


----------



## L0rdGwyn (Jun 7, 2021)

OctavianH said:


> I am not experienced and never really cared about tube construction, except the cases when I wanted to identify properly one to avoid buying a fake. From what I see here looking at the connections, the anode has to be the grey metal plate, inside we can see the grid and in the middle it has to be the cathode. However, this "mesh" (even if the word mesh means something else for me, this is not knitted) is connected to one of the pins and also connected inside:



It's a shield, grounded to pin 1, the gray plate is the anode.  Sellers on eBay know true mesh plate tubes are desirable, hard to say whether or not they are aware that the shield isn't the "plate", but probably not.


----------



## triod750

L0rdGwyn said:


> It's a shield, grounded to pin 1, the gray plate is the anode.  Sellers on eBay know true mesh plate tubes are desirable, hard to say whether or not they are aware that the shield isn't the "plate", but probably not.


There are sellers and then there are experienced sellers.....

An amp designer told me once that mesh anodes were abandoned because they weren't that durable. This could be true - I don't know. But they look hot in service. Or cool, if you prefer that description.


----------



## UntilThen

OctavianH said:


> Yes, it is the Fivre 6C5G brown base, sold by Langrex here. In the middle it is a Philips 6SN7WGTA. But it is only for "glow" purposes, I use only 2 x single triodes or 1 x double triode at the same time. At the moment I have selected Single Triode on the input switch so the one in the middle has the plate and grid unconnected. It lights and looks like I have 3 inputs but in truth, only 2 of them are used now. I know my pictures are misleading, one might think I use all 3 since all 3 glow. I have tried yesterday some 6SL7.



That's how Odyssey will be. Either EL11 or 6SL7 on at any one time. The driver input rotary knob will now have only 2 positions. Either EL11 or 6SL7. Decided not to have the 3rd position where both EL11 and 6SL7 are working at the same time.


----------



## OctavianH (Jun 8, 2021)

I am glad that we clarified the situation of the mesh plate of Fivre 6C5G without the need to smash the tube with a hammer. I have only one pair and I quite like them. One thing I do not quite like is that these tubes are a little bit microhponic. If I bring the volume to 0 or touch the glass with my finger I hear a "glass" noise in my headphones. It is the only pair of tubes which does like this, however if you do not touch them and leave volume alone they are fine. Eternity is dead silent on every combo I tried, except the problems I mentioned before, which are related to the tubes. In the last weeks I also heard some crackling when EL3N were heating, but that was happening exactly the same with them on Elise. Since all my adapters broke and I am faithful to my principle of "no adapter, no top cap" I do not think I will use them too soon.

But what I will use a lot, because I consider them the great winners of my rolling activities, are the EL34. I was lucky to find at decent prices a few pairs, so now I will be able to try and observe differences in sound between several brands/models. For example, I was able to find a pair of Philips xf5 with date codes similar "L1L", double D getter manufactured in 1961. After reading about them here I got the courage to bid for them and honestly it was one of my best decisions. Next in line are a pair of RFT and one Mullard xf2. And with these I am done, these 4 pairs will keep me busy a long time and help me understand more about this wonderful tube.





I will not say more about them now, because I need more time, but these are a little bit different sounding than my pair of Tesla EL34. More to come, about EL34.


----------



## OctavianH

Good morning, a good coffee is always better with some 6C5G and some 6F8G. I listen to the 6C5G at the moment and the VT-99 is only for display purposes and glow. I spent the last 2 days with T1 and this combination of Philips EL34 xf5 and Fivre 6C5G brown base and I can say that I am quite pleased about what I hear. For me, T1 sounds good on Eternity in this combination. It cannot surpass the VO at the resolution, dynamics and quality of bass, this is no surprise for anyone, but in the end the difference is not so big to stop you enjoying them. And I realised that on my list of favourite combos, which is under development, there is not 6SN7. For me the double triode socket is only for 6SL7, 6F8G or 7N7. The 6SN7 is only for display purposes to keep all sockets filled. And the 6J5/6C5 are almost all the time winners. I guess the time of the 6SN7 is gone for me, and I think in time more and more amplifiers will have 6J5 wired sockets. Let's see when the tube market and prices will align accordingly.


----------



## UntilThen

Octa you just keep the tube rolling flag flying till I join you with Odyssey.  

I think good 6SN7 will play a big part in Odyssey. I have Melz 1578 lined up already. Possibly Sylvania 6sn7w. Aside from that maybe a Mullard ECC33 but I'm more interested in ECC32 and ECC35. 

There is a Brimar 12ax7 black plates.... tempting. Might look at expanding the 6SL7 family. Then one 596 rectifier with Woo Audio adapter and possibly one 5U4G. That's about it.

Oh I do want a pair of WE300b tubes for next birthday !!!


----------



## OctavianH

Well, I like to discover every different flavour. Rolling is like cooking for me. You add this, you add that and in the end you obtain a mixture of aromas. But later you learn that some ingredients are stronger than others and will always have a bigger influence. And some of them are not quite mixing properly with others. This is already what an experienced cook has to know. Not a very scientific explanation, but this is my level. I have a long way ahead to become Michelin certified. LOL

My strategy of mixing ingredients is that I have no strategy, just instinct and I always try to mix ingredients which have totally different tonalities. So usually warm with neutral, bold with thin, and so on. Contrasts attract and match better. Because Philips EL34 xf5 are for me more neutral, detailed, with highs a little bit rolled off, less harsh than Tesla EL34 I have decided to combine them with these Fivre 6C5G which are warm but with a very good extension on high frequencies. I think that the strong point of one type compensates the weak point of other, and here we need to add that a bigger influence, especially in the lower frequencies area, have the outputs. So you need first to decide what output tube you want to use, for the general structure of the signature, then just add some colour with the input. Well, like cooking, you decide the main ingredients, then just add some condiments.

I have no idea if what I wrote here makes any sense, but anyway.

PS. I have some thoughts about ECC35 (you told me about) and EL81. I have no idea why, these come often into my mind.


----------



## UntilThen

OctavianH said:


> I have some thoughts about ECC35 (you told me about) and EL81.



Why are you thinking of EL81 ? These are the power tubes used in Oblivion. I have 2 sets of Siemens EL81. 

I have settled down with tube rolling. I've done too much in the past. Way more than you. Having gone through Darkvoice 336se, Elise, Euforia, La Figaro 339 three times, Glenn OTL amp, Studio Six, Wa22 and recently Elekit TU-8200 and McChanson KT150 amp. I'm really done with tube rolling. 

These days I just power on Destiny and Wa22 with whatever tubes are on hand. Looking at Wa22 now I have Mullard GZ32, Sylvania 6sn7gtb and Mullard 6080 and I'm ok with that. He1000se sound good with it and LCD4 sound great with Destiny. I'll be returning to Canberra this weekend and I'll see Yggdrasil and Oblivion again. 

I think I'm slowing down on this hobby. I don't think about it so much anymore. However I have one more unfinished business. That is to hear Odyssey live.


----------



## OctavianH

UntilThen said:


> Why are you thinking of EL81 ? These are the power tubes used in Oblivion. I have 2 sets of Siemens EL81.


I do not know exactly why, I remember I read somewhere something interesting about them. This is how my brain collects information, I read a lot of forums and articles in search of some specific information but find by mistake different opinions about other stuff. I do not pay attention to them being focused on something else but some things remain in my mind as being nice. This is the case of EL81. Of course, if I'll ever decide to try these I'll do some research on them.

For me tube rolling is not a hobby but a necessity. I usually do it to find 2-3 good combinations for each headphone I own and then stop. But from time to time I have to exchange my headphone or the amplifier and then all starts again. I bought the VO when Beyerdynamic released T1.3 and discontinued T1.2 Since my pair has several years I realized it will have to be replaced by something. I do not make amp rolling or headphone rolling, my purpose is to have one amplifier flexible enough for all my music collection and, if possible, one headphone. I switched back to T1 from VO because last week, while being hot in the room in the summer, I prefered them to VO being much more lighter and having velour pads instead of those leather pads. So necessity, not something else. If I'll ever find a lighter headphone, with the sonic performance of VO and comfort of T1.2 I'll gladly switch to it and sell/renounce on these 2.


----------



## UntilThen

I have specific goals in my head-fi journey. I wanted 2 contrasting high end headphones without going over the top. I got them in He1000se and LCD4. HD650 and HD800 are still around and I usually don't count them. I wanted 2 dac but I got 3. Yggdrasil is in Canberra and M51 is here in Sydney. Bifrost 2 has been 'borrowed' by my son. 

I wanted 3 tube amps with contrasting tone and design. I got them in Oblivion, Destiny and Odyssey. That's pretty much it for me. Except for a nice pair of Tannoy.  I wanted Odyssey as a very capable headphone amp but I think it's speakers capability will surprise me.

Oh there's still Elekit TU-8200 and Woo Audio Wa22 with the very good tubes. These are spares.  

Another thing about me. I kept almost all the pictures I took of my head-fi gear, all the way back to 2015 when I started. My 1st headphones is the Beyer DT880 Pro 250 ohms and my 1st amp/dac is the JDS Lab O2/ODAC.  I bought these new. 2 weeks later I bought the HD650.

So these are my spare NEC 6AV6 drivers and Siemens EL81 power tubes for Oblivion. Something about the NEC 6AV6. It didn't arrive 4 months after it was shipped. I wrote to the seller who promptly refunded my money. 6 months later the tubes arrived !!! I wrote to the seller, telling him that it finally arrive and I would like to pay him the money but he replied - don't worry about it. It's yours ! So the super cheap NEC 6av6 is mine for free.


----------



## OctavianH

UntilThen said:


> I have specific goals in my head-fi journey.


Your head-fi retirement plans are perfectly fine for me with 2 exceptions:
- you are very passionate about this hobby -> you want to try everything you find out about
- you are very ambitious to be the best -> you want to be better than others and have more than others
Therefore you will never stop buying equipment or tubes. You will, for sure, take breaks, but then you will come back. Do not understand me wrong, this is not a problem, I look forward to your journey. You tried and you will try more equipment than others ever dreamed of and I am sure it was rewarding. I am just not confident that Odyssey will be the end.


----------



## UntilThen

Never. This is never about being better than others. It's always for myself.  I don't have the budget of some on head-fi where buying a DCS Bartok doesn't require a 2nd thought.  Besides I love the custom tube amp journey. Been through Glenn, Eric and Tomas. It's all a wonderful experience.

Just somehow I didn't get to try Eddie Current and Donald's amp. I'm sure if I wanted I would have got it but there's so many tube amps to try and I'm already looking at the best of them.


----------



## UntilThen

Maybe just maybe there might be room for another 2a3 amp like this.



or a 845 amp like this.   



This is where I transition to HiFi.


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## OctavianH (Jun 10, 2021)

Wooden knobs? That looks brutal, like the amp is filled with red wine and you just have to open it and drink a glass. LOL


----------



## OctavianH

It seems my pair of Mullard EL34 xf2 has to wait, since the seller decided to send me some cheap tubes and then claim "it was a mistake, I do not know where we send your tubes, you get full refund". The real reason was that he was not happy about the auction price. But, now I got 4 Tungsram KC1 and I have no idea what to do with them. The seller told me to keep them, he does not want to pay shipping back, most probably because shipping back is more than these value.





Avoid this seller people.


----------



## jonathan c

OctavianH said:


> Your head-fi retirement plans are perfectly fine for me with 2 exceptions:
> - you are very passionate about this hobby -> you want to try everything you find out about
> - you are very ambitious to be the best -> you want to be better than others and have more than others


This last part is completely off the mark. In this personal audio / headphone system journey, there is only one pair of ears (ex Van Gogh) to satisfy. What does that may or will change over time...


----------



## triod750

https://www.radiomuseum.org/tubes/tube_kc1.html

2V and 0,065A. You will have to stack them. Just buy some more!!


----------



## OctavianH

triod750 said:


> https://www.radiomuseum.org/tubes/tube_kc1.html
> 
> 2V and 0,065A. You will have to stack them. Just buy some more!!


No thanks. I think I'll donate these if someone is willing to pay shipping costs. If not, they go to a box which will be opened in 100 years.


----------



## OctavianH

jonathan c said:


> This last part is completely off the mark. In this personal audio / headphone system journey, there is only one pair of ears (ex Van Gogh) to satisfy. What does that may or will change over time...


I was not trying to criticize anyone, I was just saying some people are passionate and ambitious, they will be always curious to try new things so renouncement is not an option to them. I know how personal is the listening experience to everyone. In my case, even when I think I am done I always read or find about something new which makes me again curious, so this is why I think the journey will never end.


----------



## OctavianH (Jun 10, 2021)

triod750 said:


> https://www.radiomuseum.org/tubes/tube_kc1.html
> 
> 2V and 0,065A. You will have to stack them. Just buy some more!!


Ah, thinking again, I always wanted to have a tube lamp in my room. This could be a good DIY project for me. At least to connect some heaters and make some light I should be able to do, even if I am one of the most unskilled people in crafting. 4 x these light bulbs might be nice and look steam punk 
I can even build my own amplifier:


----------



## SonicTrance

OctavianH said:


> It seems my pair of Mullard EL34 xf2 has to wait, since the seller decided to send me some cheap tubes and then claim "it was a mistake, I do not know where we send your tubes, you get full refund". The real reason was that he was not happy about the auction price. But, now I got 4 Tungsram KC1 and I have no idea what to do with them. The seller told me to keep them, he does not want to pay shipping back, most probably because shipping back is more than these value.
> 
> 
> 
> Avoid this seller people.


I'm sorry to hear that! 
But, the KC1 is a directly heated triode! You know like the holy grail types, 300b etc. And it's globe shape! You might have gotten some nice tubes after all. The 2V heater is not a problem as you need regulated DC filament supplies for DHT's anyway. It's looks decently linear on the datasheet as well. It might make a nice input tube.


----------



## OctavianH (Jun 10, 2021)

SonicTrance said:


> I'm sorry to hear that!
> But, the KC1 is a directly heated triode! You know like the holy grail types, 300b etc. And it's globe shape! You might have gotten some nice tubes after all. The 2V heater is not a problem as you need regulated DC filament supplies for DHT's anyway. It's looks decently linear on the datasheet as well. It might make a nice input tube.


Hmm, I do not quite know how to use this. Any help? I think I'll need external power for 2V heaters.


----------



## SonicTrance

OctavianH said:


> Hmm, I do not quite know how to use this. Any help? I think I'll need external power for 2V heaters.


You need a new amp, or severe redesign for it to work in your Eternity. That tube operates at max 150Va and about 1mA current. Just saying it can be a nice sounding tube.


----------



## OctavianH

SonicTrance said:


> You need a new amp, or severe redesign for it to work in your Eternity. That tube operates at max 150Va and about 1mA current. Just saying it can be a nice sounding tube.


Ah, well, no new amp can be better than this one:


----------



## UntilThen

OctavianH said:


> It seems my pair of Mullard EL34 xf2 has to wait, since the seller decided to send me some cheap tubes and then claim "it was a mistake, I do not know where we send your tubes, you get full refund". The real reason was that he was not happy about the auction price. But, now I got 4 Tungsram KC1 and I have no idea what to do with them. The seller told me to keep them, he does not want to pay shipping back, most probably because shipping back is more than these value.



This is so dodgy. You can and you should complain to ebay. You won the auction for the EL34 tubes and now the seller tells you he doesn't know where he send your tubes and try and appease you with tubes you have no use for. 

I have never seen a seller like this. Incredible.


----------



## OctavianH

UntilThen said:


> This is so dodgy. You can and you should complain to ebay. You won the auction for the EL34 tubes and now the seller tells you he doesn't know where he send your tubes and try and appease you with tubes you have no use for.
> 
> I have never seen a seller like this. Incredible.


Yes, this seller was my first experience of this kind. I have no time or energy for fighting, I just want to warn the community against this one and this kind of behaviour. I have not lost any money, just time and some hope to be able to try Mullard xf2 with Philips xf5 EL34. But I am patient and I will be able to get a pair of Mullard xf2 sooner or later. Let's hope others will no be caught in traps like this one.


----------



## UntilThen

OctavianH said:


> I was not trying to criticize anyone, I was just saying some people are passionate and ambitious, they will be always curious to try new things so renouncement is not an option to them. I know how personal is the listening experience to everyone. In my case, even when I think I am done I always read or find about something new which makes me again curious, so this is why I think the journey will never end.


It's because I understand you. You may not express it very well in English but I'm ok with that.

I just need to clarify. Nothing I buy is just a passing fad. I research most of the items before purchasing them. LF339, Wa22, TU-8200, GOTL, Studio Six, Oblivion.... ah Oblivion.   This was pure chance. Tomas approach me to do a review.

Secondly it's never about competition with anyone. I could care less what others buy. It's all for my own enjoyment and ears. I buy within my means and after careful consideration. Which is why I have not gone the route of Chord Dave or TT2 which many have. Why? Because I am happy with Yggdrasil. Simple as that. And I have auditioned TT2 + M'Scalar with Auris Nirvana and Susvara at the shop.


----------



## UntilThen

Now to change the topic. Was watching this video and this old tube amp from Philips factory is very interesting !


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## OctavianH (Jun 10, 2021)

UntilThen said:


> It's because I understand you. You may not express it very well in English but I'm ok with that.


Yes, I have to say that English is not my mother tongue. I speak it up to a level, more technical let's say, but sometimes what I try to express is a little bit off road when written in english. I realize this after I read comments and see how people perceived it. I respect everyone on these forums, after all we are here just characters on a journey, and respect and willing to help should be a priority for each one of us.

Later edit:

Hmm, 4 x 10A fuses? EL34 as drivers? And that blue light. Let's not forget those 2 big tubes at the top. I'll need a second job only for the Electricity bill for this one.


----------



## OctavianH

And we discussed about tubes, about sellers, about people with passion, about people with ambition and in the end, after the coffee from this morning the night came...


----------



## OctavianH

And if we have the night, the glow, what do we need more? The gods!



The drum solo in the beginning sounds killer on EL34 and T1. Mindblowing.


----------



## jonathan c

OctavianH said:


> Yes, I have to say that English is not my mother tongue. I speak it up to a level, more technical let's say, but sometimes what I try to express is a little bit off road when written in english. I realize this after I read comments and see how people perceived it. I respect everyone on these forums, after all we are here just characters on a journey, and respect and willing to help should be a priority for each one of us.
> 
> Later edit:
> 
> Hmm, 4 x 10A fuses? EL34 as drivers? And that blue light. Let's not forget those 2 big tubes at the top. I'll need a second job only for the Electricity bill for this one.


Two eyes...midsection...intestines...it must be a Tubot !...


----------



## OctavianH

And since I've switched from my FLAC source to Youtube to watch Judas Priest's Painkiller, I've decided to listen to a song I've not listened in 25 years. During high school I was quite a big fan of Type O Negative. Since then I've forgotten them, but there is always a time to remember. I've seen them last time live around 10 years ago, Peter was totally drunk as always, but his voice was all the time above many others. That's the problem of the rock stars, they never know when to stop.



Anyway, this was a very good test for my distorted guitars on Eternity and EL34.


----------



## UntilThen

OctavianH said:


> And we discussed about tubes, about sellers, about people with passion, about people with ambition and in the end, after the coffee from this morning the night came...



My passion is slowly seeping away lol. After Oblivion, I thought it's almost gone and that was it. However I came back with a vengeance. Lost count how many amps after Oblivion. Dabbling in mid tier solid states has been interesting. It shows me what Taurus, Mjolnir 2, Questyle CMA 12 and v280 can do. On the mid range tube amps front, LF339i, Wa22 and TU-8200 are all very good but there are better.

Eternity does look good (haha pun intended) and you should enlarge that photo and hang it up.


----------



## UntilThen

My tubes have been safely delivered to Tomas ! Send on 22nd May and delivered on 10th Jun. There's still no news from Sowter.


----------



## OctavianH

UntilThen said:


> Eternity does look good (haha pun intended) and you should enlarge that photo and hang it up.


Eternity is an incredible little amp, with a lot of potential.

A few days before receiving Eternity, while Tomas was still building it, I was writing to him that I would like to personalize Eternity and paint the logo of Slayer on the round transformer. And Tomas told me "Do it". I told him I would never do this because the reselling value will drop drastically. Now, I do not really want to sell it, I love it. So painting the Slayer logo on it might become a reliable wish.


----------



## OctavianH (Jun 11, 2021)

Eternity can be considered medicine after a full day of work. I've listened to it the whole day but because I had a huge amount of stuff to do my mind was elsewhere and the music was just in the background. Now in the evening I can focus again and I am, as usual, surprised about how effortless is the presentation of Eternity. This is the word: effortless. I cannot describe it, it is something you perceive but it is hard to come with arguments and scientific explanation.





On Elise from time to time I had the feeling that the sound quality was fluctuating. I was always thinking about the USB connection to my DAC, or maybe that I am tired and because of that perceive the signature differently than on the previous day. On Eternity I never got this feeling of fluctuation, the sound signature is presented constantly in the same form, let's call it "stable". It might be an effect of the CCS and the new design, compared to the classic OTL. I have no idea, I just know that I like this.


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## UntilThen (Jun 11, 2021)

OctavianH said:


> Eternity can be considered medicine after a full day of work. I've listened to it the whole day but because I had a huge amount of stuff to do my mind was elsewhere and the music was just in the background. Now in the evening I can focus again and I am, as usual, surprised about how effortless is the presentation of Eternity. This is the word: effortless. I cannot describe it, it is something you perceive but it is hard to come with arguments and scientific explanation.



I've spend countless days with Oblivion in this manner. After work everyday, I have to power it on and listen to music with my headphones. Usually it's background listening but every now and then, I do nothing but just listen to music. That's when I say wow. 

Now it's 2 weeks since I use Oblivion but I'm sure I'll be wow again when I return to Canberra with my LCD4 and He1000se.


----------



## UntilThen

Sydney on a sunny winter day.


----------



## UntilThen

This is life after tube amps. 😜


----------



## OctavianH

UntilThen said:


> Sydney on a sunny winter day.


You are lucky to call that winter, here we have large amounts of snow and temperatures below 0C with a quite good margin.


----------



## UntilThen

OctavianH said:


> You are lucky to call that winter, here we have large amounts of snow and temperatures below 0C with a quite good margin.



I had an incredible day. Was worth going out and leaving my head-fi behind for a day. Such a beautiful day spent with close ones.


----------



## UntilThen




----------



## OctavianH

Sydney is a beautiful town, thanks for sharing. I love these towns near the water, maybe because I live here in the mountain area. So everytime I have a chance to travel I choose towns where I can see some water and ... ah well, find some good beer. I like Hamburg for example.


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## OctavianH

Not as nice as Sydney, but for sure tasty. A musical beer.


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## SonicTrance

Beautiful pics! @UntilThen I wish Sweden had winters like that!


----------



## OctavianH

I was looking a little bit on Ebay for KT170, quite expensive. And they are not available in Europe. So I'll have to wait, at those prices you get a nice pair of Mullard EL34 or a quad of RFT EL34. So not paying something like that for new production tubes.


----------



## UntilThen

OctavianH said:


> I was looking a little bit on Ebay for KT170



Can Eternity use that?


----------



## OctavianH

UntilThen said:


> Can Eternity use that?


Yes, why not, it can use KT120 and KT150 so I do not see why KT170 would be a problem. But honestly KT150 sounded very artificial for me, so I doubt I will ever want KT170.
I've just received the money from the seller who cancelled my order for the Mullard xf2 EL34, so now the hunt for another pair begins.


----------



## UntilThen

OctavianH said:


> Yes, why not, it can use KT120 and KT150 so I do not see why KT170 would be a problem. But honestly KT150 sounded very artificial for me, so I doubt I will ever want KT170.
> I've just received the money from the seller who cancelled my order for the Mullard xf2 EL34, so now the hunt for another pair begins.



Tomas told me he sees no reason why KT170 cannot be used in Odyssey although he cannot confirm because he cannot find specs for it yet. In the time I've with KT150, I'm not that convinced it's great with headphones. It sounds big... literally but notes are not that precise like you get when you use KT88, EL34. Maybe I need more time with KT150. 

Octa, live with and listen with KT150 for 3 months then tell me what you hear. Not just for a few hours or days. Take it into weeks and months. Then tell me what you hear. In this tube rolling game you need time and impatient person need not apply.


----------



## OctavianH

UntilThen said:


> Octa, live with and listen with KT150 for 3 months then tell me what you hear. Not just for a few hours or days. Take it into weeks and months. Then tell me what you hear. In this tube rolling game you need time and impatient person need not apply.


I know, but the problem is that if I do not like a combo I do not have any energy to listen to it. In my case KT150 was nothing interesting from the first minutes. And it reminded me about KT88 on steroids, so, not quite my type. When I have KT66 and EL34/KT77 it is hard for me to listen to KT150. I have a pair here but I keep it just for collection.


----------



## UntilThen

Octa, at some point I would like to try EL156. It's called the dream of all audiophiles and one of the best tubes in the world.  

After that, I'll retire from the tube world. I've been watching too many kung fu movies. You know in the movie, the sword fighter gives up his sword and retire from killing and hacking.... and live happily ever after with a beautiful dame? 

https://tubeguru.eu/el156-se/


----------



## OctavianH

UntilThen said:


> Octa, at some point I would like to try EL156.


Then you'll need these.


----------



## UntilThen

OctavianH said:


> Then you'll need these.



Ah not so soon because the latest pictures of Odyssey gave me heart palpitations. Besides EL156, I'm thinking GEC TT21 if not the GEC KT88. However I should really put my money on an Abyss 1266 TC instead of expensive tubes. That's next year.


----------



## OctavianH

What's so special about Abyss 1266 TC? I read about them, never listened to them, so ...


----------



## UntilThen

OctavianH said:


> What's so special about Abyss 1266 TC? I read about them, never listened to them, so ...



It makes your brains bigger !


----------



## OctavianH

The weekly post about Eternity during evening.






And the one about tube glow.





No rolling, just some inputs to burn them in, 60 hours each pair. In the meantime I ordered some spare parts to repair my T1.2 (a leather headband and some earpads). It is old and needs some attention from my side.


----------



## OctavianH (Jun 17, 2021)

What do we have here? I'll tell you what we have: stuff to do. Philips EL34 xf5 double D-getter vs Mullard (rebranded Valvo) xf2 double O-getter.
The battle of the Giants! Oh, how I waited for this, more than the France - Germany football game! (I am not a football fan, but that was quite good on Tuesday).





I had to put back my VO to be sure I am able to assess these properly. Also checked a little bit how are the currents going on Eternity, and things are fine and similar to what was measured. All looks good.





I plan to keep these Mullards some time on Eternity and check them with different inputs, but from the first hours I can say that these xf2 have a darker nature, with high frequencies roll off. I read a lot about EL34 and these were also my expectations. From the first hours, even if the xf2 have a very organic and bold sound, I prefer somehow the xf5. That one is more neutral, somehow with better mids and highs. I was never a bass freak. After I will get to know better these 2 pairs and how are these are comparing on several records, genres and so on, I'll put them to the final battle: the KT77. My mixed pair of GEC/Genalex KT77 remained to me the best I was able to hear on Eternity and in my whole life in this hobby. Now we will see how KT77 stands in front of some very nice and interesting EL34 pairs. And of couse, let not forget the Tesla EL34 with double angled O-getters which can sit without problems at their table. It is close. It is a pleasure for me to listen to every pair of EL34, every minute is special, all pairs having their own idenity and a very nice signature.





And I have a very good companion in my journey, the latest Helloween album!


----------



## OctavianH (Jun 17, 2021)

And speaking of kings, I could not resist to try again my pair of GEC/Genalex KT77.





I decided for this session to try the latest Sweet Oblivion album, Relentless, which I was listening before on the Mullard xf2 OO-getter. And yes, NOS KT77 kicks ass of every pair of EL34 I have. Not as dark as the mullards, but those liquid mids and the overall level of details and emotion is just better, for me, than every pair of EL34. Kings will remain kings. However, EL34 remains a strong competitor, in some cases better, because it compensates some production problems on several albums. But for the best sounding ones, at least for me, KT77 remains on top, it is alive, vibrant and emotional, with an incredible level of detail. The ultimate EL34 like someone was saying on this thread some time ago.

This was just an experiment, I had to compare the xf2 to the kings, just to see if I remember correctly, now I'll go back to the xf2 to learn more about their nature. But the reference remains GEC KT77. They are rare, they are expensive, they are the best.

In the end, my EL34 army:


----------



## OctavianH

And the GEC KT77 is the beauty king. It has the best glow and with that short brown base and round top is special. This is my endgame.


----------



## UntilThen

The Philips 6CA7 double D getters with brown base were the ones I would get if I have to get another pair of EL34. Of course my supplier tease me with the metal base base.

I'm resting on my tubes purchase because I'll put my money on another pair of headphones if I wanted to . . . and speakers  Picking up a pair of Dali next week. Heavens help me if I started rolling speakers.


----------



## OctavianH (Jun 18, 2021)

UntilThen said:


> The Philips 6CA7 double D getters with brown base were the ones I would get if I have to get another pair of EL34. Of course my supplier tease me with the metal base base.


I am not brave enough to think about the metal base versions, I'll let others to decypher their mysteries. I'll focus on the "affordable" versions. I still consider the EL34 the big winner for this amplifier, at least for my taste. I like the NOS KT77 more but those fail on the price/performance ratio.



UntilThen said:


> Heavens help me if I started rolling speakers.


Ah, hmm, your wallet might be in danger. I read this.


----------



## OctavianH

I returned again to the Mullard EL34 xf2 double O getter and on specific albums I quite like this laid back sound, it adds weight to the music, especially on older recordings from the 90s which were suffering from a very thin production. Even if I will always prefer a more linear sound, with well extended highs, I have to admit that I quite like this sound on specific records. Every flavour of EL34 is nice and compensates something, you just need to know when to use it.


----------



## whirlwind

OctavianH said:


> I returned again to the Mullard EL34 xf2 double O getter and on specific albums I quite like this laid back sound, it adds weight to the music, especially on older recordings from the 90s which were suffering from a very thin production. Even if I will always prefer a more linear sound, with well extended highs, I have to admit that I quite like this sound on specific records. Every flavour of EL34 is nice and compensates something, you just need to know when to use it.


Very nice....a laid back sound with great weight to the music is my preference with my type of music.

So you can bias your tubes in ?


----------



## UntilThen

Hello fellows, it's the weekend. I can't roll my EL34 in but I'm using my 300b tubes.  And Octa I'm starting off cheap with speakers. Let's see how high I can go with tube amp friendly speakers.  

Next pair of speakers I'm getting next weekend are the Dali Concept 6. Dirt cheap and 91dB sensitivity into 8 ohms and requires only 30 watts. I reckon Odyssey will drive it well.


----------



## OctavianH

whirlwind said:


> Very nice....a laid back sound with great weight to the music is my preference with my type of music.


This comes at the price of a rollof in the high frequecies which is, for me, on some specific albums, a deal breaker. I listened yesterday to some poorly produced albums which were also remastered, and honestly the remaster did not help at all. In this case, this laid back sound made them sounding better on this amplifier which can be sometimes picky because it is focused on soundstage and detail and those might show you in your face the problems from the recording. But going to better produced albums I started to feel the disadvantage of the bold weighty sound. Of course, these can be paired with brighter inputs so you can reach equilibrium.


whirlwind said:


> So you can bias your tubes in ?


Yes, the amplifier allows grid bias adjustment per stage (for both tubes in each input/output stage). I have a trimmer for inputs and one for outputs and I adjust the negative voltage. But I have also a range in which I have to keep the current so the circuitry (gyrator, CCS and so on) will work properly. In the case of the output stage where the EL34 are used the range is 15-24mA, tubes working optimally around 20mA. Now, with beasts like these, which draw at startup around 3-4mA more, you need to have quite matched tubes to be able to use them in this amplifier without stress. In my case, these xf2s have 3mA between them at the same grid bias. So I adjusted the grid bias to keep the stronger one when properly heated at 19mA and the weak one around 16mA. But at startup, these beasts draw 23mA/20mA:





So, yes, I can bias my tubes, per stage not per tube, but I have to be careful to keep both of them in the allowed range at startup (first let's say 15 min) and also during normal use. This makes me always search for electrically matched pairs, and I use a tube tester to check each tube before using it in Eternity. Since I have one mA meter/stage and a switch to set it to measure left/right channel, I always determine the strong one from the pair with my tube tester, then set the meter for the socket where I will insert this one (usually left) and then knowing the difference in mA between them I estimate the current from on the other channel.
The amplifier has a 50mA fuse for the output stage, which normally limits the current to 25mA if both tubes are electrically matched, but if not one might draw more than the other before the fuse blows (here I hope I understood well the design from Tomas, he can correct me if I said something wrong).


----------



## SonicTrance

OctavianH said:


> Tomas, he can correct me if I said something wrong


You didn't say anything wrong. What I will say though, just so others know, is that you don't have to have a tube tester and match the tubes for use in Eternity. Matched tubes helps of course but it's not a necessity.


----------



## OctavianH

Eternity has already 2 months. I received in in the morning of 20.04. Since then I had the chance to listen to it around 800 hours. More to come.





When it will reach 1 year I will rewrite my review about it, and do it properly. Until now it was a sketch.


----------



## UntilThen

Glad that it’s coming along nicely and you’re keeping dates. 😊


----------



## OctavianH

I found a very good synergy between my pair of Fivre 6N7G and the Mullard (Valvo) EL34 xf2. So I guess a few days I will remain on these. In the meantime I put all my other outputs in the box, so now I have only my pairs of EL34 and the 6J5/L63 or 6N7G in the drawer. This tells me clearly my days on the 6SN7 path are gone. I do not even care about trying those.


----------



## SonicTrance

OctavianH said:


> I found a very good synergy between my pair of Fivre 6N7G and the Mullard (Valvo) EL34 xf2. So I guess a few days I will remain on these. In the meantime I put all my other outputs in the box, so now I have only my pairs of EL34 and the 6J5/L63 or 6N7G in the drawer. This tells me clearly my days on the 6SN7 path are gone. I do not even care about trying those.


I see you have found your special preference of tubes! =) I might have to get some EL34's


----------



## UntilThen

SonicTrance said:


> I see you have found your special preference of tubes! =) I might have to get some EL34's


I would like you to try EL11 and EL12 spez later and tell me what you think. 😊


----------



## OctavianH

SonicTrance said:


> I see you have found your special preference of tubes! =) I might have to get some EL34's


That might be one of your best decisions.


----------



## SonicTrance

UntilThen said:


> I would like you to try EL11 and EL12 spez later and tell me what you think. 😊


Oh I will! I actually have already in Levi's Infinity. But his EL11's were noisy. I had to use a dual EL11 to 6SN7 adapter as well, maybe the adapter was at fault. 
The operating point will be very different for the EL12 spez in Odyssey than it was in Infinity though! I'm looking forward to trying it out!  



OctavianH said:


> That might be one of your best decisions.


I'm also looking forward to hearing the 300b Infinity! I'm doing the chassis work today!


----------



## UntilThen

SonicTrance said:


> Oh I will! I actually have already in Levi's Infinity. But his EL11's were noisy. I had to use a dual EL11 to 6SN7 adapter as well, maybe the adapter was at fault.
> The operating point will be very different for the EL12 spez in Odyssey than it was in Infinity though! I'm looking forward to trying it out!



I've never heard the EL11 and EL12 spez combination in an amp build to use them. The closest I got was using them in Feliks Audio Elise and Euforia but those amps were not build for those tubes.

So yeah I'm dying to hear this combination where the operating points are correct. Might resurrect the Klangfilm amps of yesteryears. 



SonicTrance said:


> I'm also looking forward to hearing the 300b Infinity! I'm doing the chassis work today!



Curious about a 300b Infinity too.  Is this for a client or yourself?


----------



## SonicTrance

UntilThen said:


> Curious about a 300b Infinity too.  Is this for a client or yourself?


It's for a client


----------



## OctavianH

SonicTrance said:


> It's for a client


And after that one, what plans do you have?


----------



## SonicTrance

OctavianH said:


> And after that one, what plans do you have?


I'm wide open after that one!


----------



## UntilThen

SonicTrance said:


> I'm wide open after that one!



Strangely someone message me and say that he's saving for an Odyssey.


----------



## UntilThen

Lots of space now both in the room and racks. When Odyssey comes, I'll reshuffle the components.


----------



## OctavianH

Your room looks very nice. I am sure Odyssey will be a very nice addition. I just got home and after a full day with a lot of sun I need a break, so a beer is always welcomed.





Listening currently to the latest Sorcerer album. I am old school, only listening to full albums, sometimes discographies, when possible. I am burning in my Fivre 6N7G which are a very good pair to the Mullard (Valvo) EL34 xf2. The only problem I have is that I would like to own a light and comfortable headphone with a decent amount of detail to please me. I was looking at Audio Technica ATH-AWAS but I am not sure if it is a good choice. Closed back, seems decently warm, some consider it good for rock music.


----------



## OctavianH (Jun 24, 2021)

How far away is able a song to take you. Sometimes you think you know everything because you've listened to it 100 times. But there are special songs, those ones which are different every time depending on your mood and ablility to adapt to their meaning. Such a song for me is Megalomania. This one has no age, does not need any presentation, if you do not know it, you know why. But it has something to say every time you listen to it. Incredible.


----------



## UntilThen

OctavianH said:


> I was looking at Audio Technica ATH-AWAS but I am not sure if it is a good choice. Closed back, seems decently warm, some consider it good for rock music.



I go through some cycles. From loving details and clarity to warm and cosy. So it's a back and forth between LCD4 and He1000se for me. I also spend more time with speakers now. It's not planned. It just happen. Probably because I can listen to speakers now anytime I want and I've rearrange the room to suit speakers now.

So a month ago, I was planning mentally on Susvara or Abyss 1266 TC but now it will have to take a back seat because I really enjoy listening with speakers powered by the 300b amp. I know Odyssey has even more power to drive speakers. So am looking forward to that.


----------



## OctavianH

Yesterday I had 25C in my room, so it was a good time to measure again some temps on the chasis of Eternity. To my surprise, everywhere I measured (on the trafo, near the exhaust holes) I had the same 37C as I measured in Spring. Impressive, Eternity is a nice and cool amplifier. 

I also adapt to warmer or more neutral setups and start to prefer them after a while. At the moment I am on the "dark side" with these EL34 xf2. I read a little bit about Abyss 1266 TC (there is an offer on the Classifieds from Europe) and it seems an interesting headphone. Also the LCD-4 seems to be good. Too many nice headphones, too little time.


----------



## UntilThen

I would have thought that LCD4 or Abyss 1266 TC would suit metalheads to a T.


----------



## OctavianH

UntilThen said:


> I would have thought that LCD4 or Abyss 1266 TC would suit metalheads to a T.


Every metalhead has a wallet which is not metal.  But I have hard times to forget about them.


----------



## UntilThen

You might even love the Meze Empyrean. It's a more relaxing tone and has to be the most comfortable headphone around.


----------



## UntilThen

I have some time now and I spend it with comparing these 2 pairings...

Oblivion > He1000se

Destiny > LCD4

Both fed by Yggdrasil and on the same song... 

I really love the contrast of both setup. I love both. Incredible tone. Music sound live and real.


----------



## OctavianH

UntilThen said:


> You might even love the Meze Empyrean. It's a more relaxing tone and has to be the most comfortable headphone around.


How is Empyrean compared to LCD-4? I thought those are close in signature (dark, relaxing and so on).


----------



## UntilThen

OctavianH said:


> How is Empyrean compared to LCD-4? I thought those are close in signature (dark, relaxing and so on).



Empyrean is darker.  LCD4 bass goes deeper too. LCD4 high end is more revealing than Empyrean but at that level, you hear everything. There's no lack of details in Empyrean. The best thing to do is to hear it for yourself, preferably with your own dac and amp.

Anyhoo, here's another shot of the setup.


----------



## OctavianH

UntilThen said:


> Empyrean is darker.  LCD4 bass goes deeper too. LCD4 high end is more revealing than Empyrean but at that level, you hear everything. There's no lack of details in Empyrean.


Thanks, this is how I was thinking. You just confirmed me I would prefer LCD-4 instead of Empyrean.


----------



## UntilThen

OctavianH said:


> Thanks, this is how I was thinking. You just confirmed me I would prefer LCD-4 instead of Empyrean.



Don't be so sure. Empyrean has an an easy, relaxing tone that is very enticing. I can very clearly remember auditioning Empyrean with Ampandsound Encore (poor man's 300b amp). If you're a details lovers, you won't like it but this is just smooth, warm and organic. 

I do much prefer my own setup though.  

Meze Empyrean with Ampandsound Encore.


----------



## UntilThen

Listening to 'Five Finger Death Punch' A decade of destruction now.  Pretty good on both setups of mine.


----------



## UntilThen

I was listening to this on Roon / Tidal then I switch to Youtube and this video is just mad. 122 million views.


----------



## OctavianH

I am not very much into what these guys are doing, but they have a song with Rob Halford and they even performed it live with him.


----------



## Yetiman72

Have a Listen to these Matt, ( Rag'n'Bone Man )


----------



## UntilThen

Hey Shane, good choice. It's been a while since I sit and just listen to music and I've 2 setups now to alternate. It's a cold night but cosy indoors and perfect for music enjoyment.


----------



## Yetiman72 (Jun 25, 2021)

Hey Matt, Yes I just stumbled onto them and think there Great this is two songs off two different Albums of there's .


----------



## OctavianH

Friday Beerday! 27C in the room. Luckily I have liquid cooling. Hell, I feel every gram of the Verite Open but I still cannot stop listening to them.


----------



## OctavianH (Jun 26, 2021)

@UntilThen I found an amplifier for your future Abyss 1266 TC.


----------



## OctavianH

I've got an obsession with the latest Helloween album. I cannot stop listening it for 2 days. I thought these end in highschool.
Anyway, what really matters is that I was not pleased about the sound when using Beyerdynamic T1.2 until I paired Mullard EL34 xf2 with Fivre 6C5G brown base from Langrex. I start to think these are some of my most special drivers. I guess I have to buy several more pairs, because these sound incredible with many EL34 pairs and the synergy of EL34 with 6J5/6C5 is very good. The magic is the classic recipe, laid back outputs with some warm inputs with good extension on high frequencies, but what these do for the T1.2 si quite incredible. I would like to listen more to Verite Open which is a superior headphone but at 27C in the room the T1.2 is a much more comfortable solution.


----------



## hpamdr

After almost a month without tube amp nor good headphone (except bose quiet comfort)....
I'm back to home Eternity is still dead silent and found a good setup with T1 EL39 and 6J5.  EL39 is a bit less tubey than EL34 and with a flatter response than KT66 and KT88. Pairing with 6J5 and 6C5 gives the sound i like for T1. With Heddphone i still prefer GU50 as output as it give the extra current to be extremely tight and dynamic ! (but HD800s and T1 are more suitable for Summer)



The option to have no Output is really what i advise to anyone choosing rolling option.. It is much comfortable for me than unplugging headphone !


----------



## SonicTrance

hpamdr said:


> After almost a month without tube amp nor good headphone (except bose quiet comfort)....
> I'm back to home Eternity is still dead silent and found a good setup with T1 EL39 and 6J5.  EL39 is a bit less tubey than EL34 and with a flatter response than KT66 and KT88. Pairing with 6J5 and 6C5 gives the sound i like for T1. With Heddphone i still prefer GU50 as output as it give the extra current to be extremely tight and dynamic ! (but HD800s and T1 are more suitable for Summer)
> 
> The option to have no Output is really what i advise to anyone choosing rolling option.. It is much comfortable for me than unplugging headphone !


I see you got the "no-touchy" type of anode cap!


----------



## hpamdr

SonicTrance said:


> I see you got the "no-touchy" type of anode cap!


This anode cap wire can be used for all kind of cap size and for sure i do not touch it while the amp is on !
I made it for EL11Spez but it seems that my tubes are not as silent as the EL39 are !


----------



## OctavianH (Jul 1, 2021)

I am circling through different pairs of EL34 combined with different pairs of 6J5 and the Beyerdynamic T1.2 because of the high temperatures during summer.
Each pair of EL34 has a common ground but also some differences, and it is incredible to try each of them with complementary pairs of 6J5. These are fine tunings but I enjoy them a lot.

*1) Philips EL34 xf5 (code L1L, double D getters, brown base)*
This is the most neutral and technical pair, the most "audiophile" one, providing best resolution, less bass but more details and a more linear sound. It might sound a little bit dry or towards solid state, but very dynamic, definitely the best in terms of technicality and analytical sound.
*2) Mullard EL34 xf2 (code B1J5, double ring getters, blackish brown base)*
This is the laid back one, king of bass and holographic sound. Punchy and very well defined bass in detriment of roll-off in high frequencies area, a bold tube and very charismatic for those who prefer a warm and laid back sound.
*3) Tesla EL34 (double angled ring getters, brown base)*
I left this one at the end not because of the price, but more because I find it retaining something from both pairs above. It is warmer than the first one, with better high frequency rendering but also somehow more aggressive. Some might have a problem with that but in my case, with T1.2 which is very polite and warm on Eternity, that aggressive edge just makes it more pleasant. So Tesla is somehow in the middle, combining the sound of both pairs above and adding a level of aggressivity.

Here are the Philips EL34 xf5 and the Mullard EL34 xf2:




These are some personal opinions, strongly related to current setup and headphones. But still, I hope they will let anyone have an idea about how different pairs of EL34 are sounding on Eternity. The winner is, for sure, Tesla EL34, because the price/performance ratio is incredible (you can find a pair around 80 EUR). Of course, both other pairs have their advantages, the Philips being maybe for the audiophile seeking details and a linear sound, the Mullard being for the one seeking a more tubey and holographic sound.

I like all of them, but I had to split them into categories and then assess their qualities and defects. No EL34 pairs sounds wrong on Eternity and no pairing with 6J5 is wrong. These are just flavours and match different setups, but the overall synergy remains great. For me EL34 and 6J5 remain the great winners for this amplifier.

And here is the Tesla EL34, on Eternity, being my currently preferred pair:



Why I prefer it now? Because it has enough bass and warmness to make T1.2 sound good but not too bloated, and because the high frequency extension and that aggressivity I was mentioning are complementing a little bit the signature of the T1.2. I tried with it several pairs of 6J5 and kept 2 as reference, the GEC L63 clear glass brown base from the picture and the ST shaped grey glass one (older version). Both are good, both are nice, I alternate them depending on the album I listen, currently listening to old Iron Maiden albums like Somewhere in Time (1986) or Seventh Son of a Seventh Son (1988), this one being my all time favourite.

Later edit:
I tried to make a picture with the grey glass L63, but evening came, tried the Night mode:


----------



## hpamdr

OctavianH said:


> I am circling through different pairs of EL34 combined with different pairs of 6J5 and the Beyerdynamic T1.2 because of the high temperatures during summer.
> Each pair of EL34 has a common ground but also some differences, and it is incredible to try each of them with complementary pairs of 6J5. These are fine tunings but I enjoy them a lot.
> 
> *1) Philips EL34 xf5 (code L1L, double D getters, brown base)*
> ...


What i have observed with Eternity is the ability to reveal more the qualities/defaults of headphone i comparison to Euforia. T1 paired perfectly with almost all tube combination on Euforia. It seems more demanding on Eternity. 
With 6J5 / 6C5: 
I did a try with EL34,KT66,KT88 and finally prefer EL39 which are less tubey and make T1 great again !
With HD800s i like more KT66 and EL34 to have better bass and not as much hight
and GU50 with Heedphone and T500rp...  wich is a dynamic booster with these headphones.


----------



## OctavianH

Yes, I have observed the same. At first I thought that maybe for a SET amp the preferred impedance is around 100 Ohm, and the 600 Ohm of the T1.2 is a little bit too much, but in the end I found combinations where T1.2 does not seem unpowered, after all the volume knob is at half when I listen to it.


----------



## hpamdr

OctavianH said:


> Yes, I have observed the same. At first I thought that maybe for a SET amp the preferred impedance is around 100 Ohm, and the 600 Ohm of the T1.2 is a little bit too much, but in the end I found combinations where T1.2 does not seem unpowered, after all the volume knob is at half when I listen to it.


You are right and probably not a power issue but more a current/voltage distribution. 6J5 drivers with amplification Factor of 20 for 4mA -7v/180V and EL34  or EL39 seems to fit well with T1 and High ouput position. KT88/GU50  with same drivers makes T1 not as flat ( Bass are deep but not clean and highs a bit too aggressive...).

@SonicTrance  do you have any Idea if the output Voltage / Current orientation can be guessed   ?


----------



## SonicTrance (Jul 2, 2021)

hpamdr said:


> @SonicTrance do you have any Idea if the output Voltage / Current orientation can be guessed ?


I don't have the figures with me right now as I'm on vacation. But, if you present a load that's 200+ ohms to Eternity, the amp will run out of current before voltage. The voltage at the output into high Z is around 13Vpp (high) and 7Vpp (low) before clipping. The current can be calculated using ohms law.

Edit correction: The amp will run out of voltage before current if the load is 200+ ohms. It will run out of current before voltage if the load impedance is low.


----------



## hpamdr

SonicTrance said:


> I don't have the figures with me right now as I'm on vacation. But, if you present a load that's 200+ ohms to Eternity, the amp will run out of current before voltage. The voltage at the output into high Z is around 13Vpp (high) and 7Vpp (low) before clipping. The current can be calculated using ohms law.


Enjoy vacation ! 
*When you will be back* can you look if output tube can influence a bit those figures for a big load ?


----------



## SonicTrance

hpamdr said:


> Enjoy vacation !
> *When you will be back* can you look if output tube can influence a bit those figures for a big load ?


Thanks!
The only difference is that if you have an output tube with lower mu you have to turn volume up to let a bigger signal through to the input stage to amplify. So a bigger signal will be present at the grid of a low mu output tube vs a high mu output tube for the same amount of volume. The output voltage and current will remain roughly the same in the end because we manually adjust the operating point to the same amount of current for every tube.


----------



## OctavianH

Some Tygers of Pan Tang in the evening. Put this band in my playlist by mistake but it was a wise choice.


----------



## OctavianH (Jul 4, 2021)

Sunday, end of the weekend. Listening to some very old Judas Priest recordings, some studio live from BBC.



I keep my T1.2 for the listening session, but VO are close.


----------



## hpamdr (Jul 8, 2021)

*Small driver test Wowwwwwwwwwwww *_using old chinese adapter _ecc88 2 6SN7 *!*

Using inexpensive *6BQ7A *Philips dual triode very well balanced bias at -3.65V (4ma at 180V) mu is around 38 (heating voltage is around 6.95/13.9V at home).
The 6BQ7 is an European model of 1951 RCA 6BK7 or  Raytheon 6BZ7 which can be a replacement for chinese 6N1 with higher mu (38 vs 33). Fivre used RCA pattent do build 6BK7 in Italia but not as good (IMO) as the Philips ones.
Most of Philips, Miniwatt, Mazda,... have been built from the 50" to late 70" in Mazda plant and are usually well balanced and with less microphonic and rfi sensibility than the US/Italian version.








With GU50 or KT88 as output it s a joy for acoustic instrument and voice.


----------



## hpamdr (Jul 9, 2021)

Today some work for EL12spez adapter and test !
El12spez are very good tube same league as EL39/EL34 . I do not have balanced pair biasing at at -8V one is around 17mA the other at 23mA.
With Eternity you have a very full and rich tubey sound and very detailed at the time. It is not as dynamic as GU50 but a very good compromise like EL39.
El12spez is a bit more tubey and as detailed and almost as dynamic as EL39. This is a wonderful tube very close to EL39 and for me a better than Tesla EL34 for precision and micro-details.



Good match with ECC31 (darker tone), 6J5 K.R. (Neutral), 6BQ7A (Neutral).
-- Edited
with ECC31 the sound is just a bit darker but much more than other input tubes. To what i have curently observed input tube just gives a flavor when the output tube gives the taste !


----------



## OctavianH

hpamdr said:


> with ECC31 the sound is just a bit darker but much more than other input tubes. To what i have curently observed input tube just gives a flavor when the output tube gives the taste !


This is exactly what I was trying to say but your words are much better. I have not rolled anything in the last week but what I read makes me think twice.

In the meantime, just finished work so Friday Beerday and a blue filter. LOL





PS. I'm hunting a pair of Telefunken EL34 but I will decide next month what to buy, this months I am over my budget.
PS2. An EL34 story. For german users: Die EL-34-Story. For english ones Google Chrome is our best friend (right click -> Translate to English).


----------



## UntilThen

Keep the impressions coming guys. There are only a few of us. Reminds me of the early days of Elise, Euforia and GOTL.  

Octa, blue filter creates a nice effect.


----------



## UntilThen

Dipping my toes in Apple Music despite having Tidal HiFi.


----------



## OctavianH

UntilThen said:


> Keep the impressions coming guys. There are only a few of us. Reminds me of the early days of Elise, Euforia and GOTL.


And a few will remain, I have no ideea if other amps with rolling addon are ordered.


----------



## whirlwind

OctavianH said:


> This is exactly what I was trying to say but your words are much better. I have not rolled anything in the last week but what I read makes me think twice.
> 
> In the meantime, just finished work so Friday Beerday and a blue filter. LOL
> 
> ...


Nice story, thanks for posting. I am a huge fan of Mullard xf2's EL34.

@leftside bought the history of EL34 book , I  think like 365 pages.....I have been tempted.


----------



## OctavianH

whirlwind said:


> @leftside bought the history of EL34 book , I  think like 365 pages.....I have been tempted.


I have also bought it, it is a very nice book.


----------



## hpamdr (Jul 10, 2021)

EL11 + EL12sp !
I finished EL11 -> 6j5 adapter.
EL11 i have bias around -8v to get 4mA at 180V with amplification factor around 21.

EL11 + EL12sp pair very well adding subtle "harmonics" to the sound. This is a great combination with Eternity and planar headphone.





*-- edited*
EL11 needs a bit more time than 6j5 driver to get hot and stabilized (2-5 minutes). With the tube I have, when starting the amp, i can hear mechanic (microphonic) noises comming from the internal elements and the glass. Once hot and as usual with Eternity all stabilize and is deadly quiet !


----------



## UntilThen

hpamdr said:


> EL11 + EL12sp !
> I finished EL11 -> 6j5 adapter.
> EL11 i have bias around -8v to get 4mA at 180V with amplification factor around 21.
> 
> EL11 + EL12sp pair very well adding subtle "harmonics" to the sound. This is a great combination with Eternity and planar headphone.



This will sound different on Odyssey.


----------



## whirlwind

OctavianH said:


> I have also bought it, it is a very nice book.


Nice.

What voltage is on the plates of those EL34's ?


----------



## OctavianH

whirlwind said:


> Nice.
> 
> What voltage is on the plates of those EL34's ?


200v, we keep them at 20mA.


----------



## whirlwind

OctavianH said:


> 200v, we keep them at 20mA.


Thanks much.....tubes should last a very long time.


----------



## OctavianH

whirlwind said:


> Thanks much.....tubes should last a very long time.


Yes, on guitar amps I think they keep them around 500v.


----------



## hpamdr

whirlwind said:


> Nice.
> 
> What voltage is on the plates of those EL34's ?


As said by Octavian, on Eternity and Infinity the plate voltage is 200V for output tubes and 180V for input Tubes. All tubes are strapped as Triode and plate voltage is fixed for all tubes, manual bias maintain 20mA for Eternity and 40ma for Infinity (25% of tolerance with fuse protection in output) 4ma in input. 
Fo comparison, Euforia and Elise use even lower plate voltages 100V in input and 140V for Output but bias is automatic...


----------



## UntilThen

Should I buy this?

https://www.stereonet.com/forums/topic/507197-fs-mullard-el38-quad-el34-adaptors/


----------



## OctavianH

UntilThen said:


> Should I buy this?
> 
> https://www.stereonet.com/forums/topic/507197-fs-mullard-el38-quad-el34-adaptors/


I have no idea about the price, but I tried EL38 in Eternity and quite like it at that time. Now, if these would sound the same in Odyssey I have again no idea.


----------



## hpamdr (Jul 12, 2021)

UntilThen said:


> Should I buy this?
> 
> https://www.stereonet.com/forums/topic/507197-fs-mullard-el38-quad-el34-adaptors/


If you do not have EL39 and price is ok for you, this could be interesting to try !
To what i have read, el38 have similar construction as EL39 but was not built as audio tube. Some firends are happy with it but most admit that EL39 is better ! To what i have tested, EL12spez is also a better tube. If you have already EL12Spez and your goal is not to roll tubes, just stay with what you have !


----------



## UntilThen

OctavianH said:


> I have no idea about the price, but I tried EL38 in Eternity and quite like it at that time. Now, if these would sound the same in Odyssey I have again no idea.





hpamdr said:


> If you do not have EL39 and price is ok for you, this could be interesting to try !
> To what i have read, el38 have similar construction as EL39 but was not built as audio tube. Some firends are happy with it but most admit that EL39 is better ! To what i have tested, EL12spez is also be a better tube. If you have already EL12Spez and your goal is not to roll tubes, just stay with what you have !



I have a new pair of EL39 and several pairs of NOS EL12 spez  but still thinking of that quad EL38 which comes with adapters too. 

Also dying to try the Radiotron 807 in Odyssey.  Also the GEC KT66, Philips Miniwatt 6CA7 and Tung Sol 6550 and assortments of different brands of KT88. My fingers are getting itchy to roll. Every day is a day closer to the Sowter transformers getting to Tomas.


----------



## hpamdr

Today one more test :
VT94 (bias -7v)+ EL32 (bias -17V)
This is a "romantic" sound which is good for acoustic music and specially harpsichord this is not the most dynamic nor the warmer tube. It is mid to high presentation ! 
I personally like the sound and it is a better match in Eternity than in Euforia. It keep the amp quite cool and is great with HD800s and T1 Summer choices !




 




_ // I use old adapter 6J7 -> 6J5 directly in place of EL34 socket. R100 from A->G2 is inside pin 4 is omitted.  Top Cap is connected to G1 (pin 5 the only needed  re-routing)
_


----------



## UntilThen

I still have a pair of Mullard EL32 smoke glass NOS NIB. Can I use this as power tubes in Odyssey, Tomas?

He's probably going to say, 'Why would you want to do that'.


----------



## SonicTrance

UntilThen said:


> I still have a pair of Mullard EL32 smoke glass NOS NIB. Can I use this as power tubes in Odyssey, Tomas?
> 
> He's probably going to say, 'Why would you want to do that'.


No you can't. The EL32 has plate dissipation of 8W max. It wouldn't last very long in Odyssey.


----------



## leftside

whirlwind said:


> Nice story, thanks for posting. I am a huge fan of Mullard xf2's EL34.
> 
> @leftside bought the history of EL34 book , I  think like 365 pages.....I have been tempted.


Latest version has input from yours truly


----------



## OctavianH

Since we are discussing about this book, I want to add a small remark: the purpose of the book is not to present a vast history of these tubes but more to describe with pictures the construction details and help you correctly identify different types. It describes a little bit every manufacturer and has some infos about each one of them but the main part are pictures and comparisons of different EL34 tubes.


----------



## hpamdr

OctavianH said:


> Since we are discussing about this book, I want to add a small remark: the purpose of the book is not to present a vast history of these tubes but more to describe with pictures the construction details and help you correctly identify different types. It describes a little bit every manufacturer and has some infos about each one of them but the main part are pictures and comparisons of different EL34 tubes.


I do not have the book, but to what i have understood it helps a lot if you want to buy and/or identify  tubes. It is paid by itself when getting a good catch on rebranded tube on ebay.


----------



## OctavianH

hpamdr said:


> I do not have the book, but to what i have understood it helps a lot if you want to buy and/or identify  tubes. It is paid by itself when getting a good catch on rebranded tube on ebay.


Exactly, this is the main purpose and area where it helps. I wanted to mention this to let people have proper expectations. The content and some excerpts can be found here.


----------



## UntilThen

OctavianH said:


> Since we are discussing about this book, I want to add a small remark: the purpose of the book is not to present a vast history of these tubes but more to describe with pictures the construction details and help you correctly identify different types. It describes a little bit every manufacturer and has some infos about each one of them but the main part are pictures and comparisons of different EL34 tubes.



Where do I buy this book? At the moment I have only 2 pairs of EL34. A Philip Miniwatt 6CA7 xf2 double O getters and a RFT EL34. The book mention EL11... interesting. Why no mention of EL12 spez or EL12 ? Or EL39 ? There's mention of EL38.


----------



## OctavianH

UntilThen said:


> Where do I buy this book? At the moment I have only 2 pairs of EL34. A Philip Miniwatt 6CA7 xf2 double O getters and a RFT EL34. The book mention EL11... interesting. Why no mention of EL12 spez or EL12 ? Or EL39 ? There's mention of EL38.


I mailed the author on the e-mail address mentioned in the link above and he gave me a Paypal account, I put the sum on it and he gave me a download link. Fast and simple.


----------



## UntilThen

Ok thanks. I took out my tubes for Odyssey today and inspected each one again. They are pristine.  I don't need more tubes for a while. They should take me a year to go through thoroughly. I stop at the Tung Sol 6550 and remembered how it sound on Eric's amp.


----------



## hpamdr

Today Experiment with HD650mod..
6J49P-DR tubes as input (a bit over stressed bias at -3.7V ) and still EL32 as output. The driver is very dynamic and with good amplification factor pairs well with EL32 (also EL34).
I use low output and turn the pot a bit more 9 O'clock, all is clear and cool even after 2 hours of listening..
Frédéric Alarie Mega Bass album in HD is really fantastic for headphone listening... Bass, Bass, Bass, Persuasions  full of details and very well recorded !


----------



## UntilThen

HD650 mod.  I had a HD650 mod but I sold it to a friend cheap because I did not like the DIY look from the outside.  Now I have an original HD650, which still surprise me time and again when I use Oblivion and Destiny to drive it. Mind you this original HD650 sounded awesome driven from my previous behemoth Sansui 907mr.

I have to try that Mega Bass album.


----------



## OctavianH

I start to regret that I have sold my HD600 and HD650. Well, you cannot keep every headphone you buy.


----------



## UntilThen

There are some nice headphones that I regret selling off. Such as my Eikon and Atticus and Verite Open. There will be a ZMF headphone later but I'm eyeing a Susvara or Abyss TC first. 

I had a short audition of Aeolus and Auteur and thought they sounded great. I like Empyrean too.


----------



## OctavianH

I am listening to T1.2 for 3 weeks since here we have more than 30C outside, in my room around 27C and I cannot use Verite Open anymore for my long listening sessions (keep in mind I use Eternity while I work and I work sometimes 12 hours/day).
I am looking for a light headphone with a warm/detailed tone and started to read this incredible review. I might give a try to the AWAS, sooner or later. I do not know other light headphone which would sound as I expect. Any recommendations? (<400g if possible and light headband).


----------



## UntilThen

I wouldn't wear a headphone for 12 hours a day.  That's why I have speakers.

You really need to try the headphones for yourself with your own setup. First hand experience is better than any reviews because we're all unique human beings.


----------



## UntilThen

I received great news for Odyssey. Tomas has received the Sowter transformers. I thought the joy of waiting for a new tube amp has worn off on me but I've never been more excited in all the years of this hobby.


----------



## OctavianH

I know, each of us has different usage scenarios. I listen to my headphones sometimes 16 hours per day and this is why comfort of a headphone is mandatory to me. For example today I started around 8AM and now it is 8:30PM, Eternity is still on near me. When I listen to music while working or studying on specific topics I am interested, I can concentrate better. I have some near field monitors on my desk but I never use them, maybe once per month, I think to reounce on them and buy a 49" ultrawide monitor instead like for example this one. It would be much more useful to me than these speakers which are decent (Adam Audio A5X).


----------



## UntilThen

Oh yeah a 49" monitor is on my Christmas wish list even though I have the 34" Acer predator now. I can keep one in Sydney and the other in Canberra.

Light and comfortable headphones I've tried are Meze Empyrean and Dan Clarke Ether 2. Both very light and comfortable. Empyrean probably more to your taste of warm and relaxing whereas the Ether 2 is light in weight and tone but it's very clear though.


----------



## UntilThen

Odyssey G9 monitor. Now wouldn't that pair very nicely with my Odyssey amp.


----------



## OctavianH

Those Ether 2 are interesting, but 16 Ohm are OK for UltraSonic amps?


----------



## OctavianH (Jul 13, 2021)

Some late night listening session, at least now the sun took a break and allowed me to have less than 27C. I know I told this several times, but look guys what Meteoblue reserves me, and I have a tube amp near:






I know others live in Australia but for me the Global Warming is real, 20 years ago we had 25C during Summer. And I have this near me on for 14 hours already:





But as wise men said, we do what we have to do. During evening when my work is done I can enjoy some live recordings and from time to time I let youtube enlighten me. For example today I watched this incredible Blind Guardian show from 2016. I was always a huge fan of the 90s scene of german speed/power/thrash bands, so the song Imaginations from the Other Side was greatly appreciated. And yes, Hansi is incredible on vocals but I also like that drummer. That guy is good.


----------



## hpamdr

OctavianH said:


> I start to regret that I have sold my HD600 and HD650.* Well, you cannot keep every headphone you buy.*


Well this is what i do.... but I'm not a compulsive buyer 
The HD650 need to be very well driven to give it's best... The mod i have is a light one, it was done by a friend. He just remove some foam, cut some plastic back to the driver and add some damping material like used for car sound system in the cup.


----------



## UntilThen

OctavianH said:


> Those Ether 2 are interesting, but 16 Ohm are OK for UltraSonic amps?



I don't see why Ultrasonic amps cannot handle low impedance headphones. Do you have an impedance switch on your Eternity? 

I have an impedance switch on Oblivion and my He1000se (35 ohms) and LCD-X (20 ohms) runs perfectly on it.

I was listening to the Ether 2 on AmpandSound Encore. Was great there.


----------



## UntilThen

hpamdr said:


> Well this is what i do.... but I'm not a compulsive buyer
> The HD650 need to be very well driven to give it's best... The mod i have is a light one, it was done by a friend. He just remove some foam, cut some plastic back to the driver and add some damping material like used for car sound system in the cup.



Yup that's the mod I did to mine. It became clearer and the bass tightens up.


----------



## hpamdr

OctavianH said:


> Those Ether 2 are interesting, but 16 Ohm are OK for UltraSonic amps?


Eternity should be fine with Ether 2 on low impedance position and with driver tube with medium to low amplification factor to ensure lowest noise.


----------



## SonicTrance

hpamdr said:


> Eternity should be fine with Ether 2 on low impedance position and with driver tube with medium to low amplification factor to ensure lowest noise.


Absolutely! Down to 4 ohms is fine


----------



## hpamdr

Rusian tubes with deaf-dumb-blind album.!

Driver 6C5s old russian batch. (bias around -6.5V (for the tube i have).  
Output GU50 (Heat 14V, bias -32V ).

Headphone HD650, K701, low output (4 Ohms tap)


----------



## UntilThen

hpamdr said:


> Rusian tubes with deaf-dumb-blind album.!



I'm listening to this album on Apple Music.  

Sometime next week, Odyssey would be in an operational state.


----------



## hpamdr

Got a pre-owned pair of EL34 Telefunken single O getter black base paired with 6C5s.. Warm and detailed sound of EL34 but a bit dryer than the Tesla...
Good match with T1 using high output (8 Ohms tap)...

Listening Maggie Reilly best of with T1 . (_for the one remembering Mike Oldfield in the 80's _) and then Mike Oldfield - Return to Ommadawn..


----------



## OctavianH

I wonder how these Telefunken EL34 sound, because from what you describe they are towards my Philips EL34 xf5.


----------



## UntilThen

I bet they have the Telefunken house sound of clarity and sparkly highs.


----------



## OctavianH

Just watched the new Iron Maiden song with Eternity. I guess it's a premiere.


----------



## OctavianH

Anyone with blues and EL34? I think I might have something for you.



This is not exactly my cup of tea, but sounds good.


----------



## UntilThen

OctavianH said:


> Anyone with blues and EL34? I think I might have something for you.



I listen to this using 2 different setup. Oblivion > He1000se and Destiny > LCD4. Both just as good. Against this backdrop I'll be evaluating Odyssey.

EL34 is an important power tube for me. EL12 spez is a predecessor of it and have similar DNA.


----------



## OctavianH

Cycling to the same tubes, I keep only EL34 as output and roll different 6J5 and my only pair of 6N7. all sound good, but I start to think I might need to get a pair of EL3N->6J5 and EL11->6J5 adapters. We will see, I think I'll need to expand a little bit my army of inputs.


----------



## UntilThen

Strapped pentodes as triodes gives off a different pleasing sound that is vivid and punchy. Such as EL3N, EL11 and c3g. Go ahead try it. As for me, I have EL11 and I can't wait to use that in a custom setup.


----------



## OctavianH

UntilThen said:


> Strapped pentodes as triodes gives off a different pleasing sound that is vivid and punchy. Such as EL3N, EL11 and c3g. Go ahead try it. As for me, I have EL11 and I can't wait to use that in a custom setup.


I've sold my Siemens C3g with Elise, but I still have a pair of Valvo EL11 and 3 pairs of Philips EL3N. So, why not, I'll think about it. I'll have to break my rule of "no adapter is best adapter" and this requires judgement and decision.


----------



## UntilThen

Should check with Tomas whether you can use those tubes in Eternity.


----------



## OctavianH

I think I can, I tried EL3N with a dual adapter EL3N -> 6SN7 and worked well, but the adapter broke, was a chinese stuff, if I'll try those again I'll use some single adapters to 6J5.


----------



## UntilThen (Jul 16, 2021)

Tomas, can I use this in Odyssey's EL11 slots?

https://www.ebay.com/itm/133818207948?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=233149&meid=b9396c261ec345298908a472e6e97854&pid=101195&rk=5&rkt=12&sd=114871438717&itm=133818207948&pmt=1&noa=0&pg=2047675&algv=SimplAMLv9PairwiseUnbiasedWeb&brand=TELEFUNKEN&_trksid=p2047675.c101195.m1851&amdata=cksum:133818207948b9396c261ec345298908a472e6e97854|enc:AQAGAAACAJy%2BdyQ97b94TMJCsf4Cs84RqMwHkOFhDKLLmDX8yXVBx7aHFS3Dx7w2rY2Mk6AYQ6IMMA7Xm48lCcODMqLbDePhFvpDwU1RZzrrXEmY7bm05i2MweDE42lYlffOGk82wt%2FI5GE4%2FQOvvUBX5nHwGHz%2BP4O2VYeJiZu12meDfqHaf%2BiKWgtPV0QdmWm7genSEeAagkUSpF3kYZBPJ%2FwCXLYh1RnKl2m2Kg4rVU6XbAJho2xnI39Nj6AJHYvJzLwostKeMVLY6%2BS8pKrPCmZAzn00yydXLHBTvTC0nj6BP17oHuzpD%2BPnxMZ1mowYtoySF5PsBn35Ext9uPdbJH%2BuF6uUvg9w3NC1wHBhj7gqwCotQps8uAe9Q%2BSu6U7c6sa7WRM5jbae%2FikGNlnGcWc8WM9Wo0qDwFrknYQnXOc32Blvm3ENMDwD0fpCJUy%2FTWo%2BN3MsgLYWp5CzHnhSJ9qK63O25Ql5yTiqM3nHiXfSJ1KmCzGI2rUie3%2FRYGsr5vwlg%2BSPSPde0feh2%2BMFQwFNRnll0zQUiIQUUnPX81N07p5KKNXG8STi%2FBOWQHO%2FW%2FDOvBrPxWxKoH%2BFIrV65vuByWASNcNyEjIUtBM5kOca3ZGMdK2B7Up1sg56D%2BX%2FDYO0KN7GzAvitV8TCC%2F0xSrOxVpC4sNwzRyK2HkaqsjGqw%2Fg|ampidL_CLK|clp:2047675


Or the EF11  
https://www.ebay.com/itm/203397047279?hash=item2f5b68a3ef:g:R0MAAOSwPrlgh0CK


----------



## SonicTrance

UntilThen said:


> Tomas, can I use this in Odyssey's EL11 slots?
> 
> https://www.ebay.com/itm/133818207948?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=233149&meid=b9396c261ec345298908a472e6e97854&pid=101195&rk=5&rkt=12&sd=114871438717&itm=133818207948&pmt=1&noa=0&pg=2047675&algv=SimplAMLv9PairwiseUnbiasedWeb&brand=TELEFUNKEN&_trksid=p2047675.c101195.m1851&amdata=cksum:133818207948b9396c261ec345298908a472e6e97854|enc:AQAGAAACAJy%2BdyQ97b94TMJCsf4Cs84RqMwHkOFhDKLLmDX8yXVBx7aHFS3Dx7w2rY2Mk6AYQ6IMMA7Xm48lCcODMqLbDePhFvpDwU1RZzrrXEmY7bm05i2MweDE42lYlffOGk82wt%2FI5GE4%2FQOvvUBX5nHwGHz%2BP4O2VYeJiZu12meDfqHaf%2BiKWgtPV0QdmWm7genSEeAagkUSpF3kYZBPJ%2FwCXLYh1RnKl2m2Kg4rVU6XbAJho2xnI39Nj6AJHYvJzLwostKeMVLY6%2BS8pKrPCmZAzn00yydXLHBTvTC0nj6BP17oHuzpD%2BPnxMZ1mowYtoySF5PsBn35Ext9uPdbJH%2BuF6uUvg9w3NC1wHBhj7gqwCotQps8uAe9Q%2BSu6U7c6sa7WRM5jbae%2FikGNlnGcWc8WM9Wo0qDwFrknYQnXOc32Blvm3ENMDwD0fpCJUy%2FTWo%2BN3MsgLYWp5CzHnhSJ9qK63O25Ql5yTiqM3nHiXfSJ1KmCzGI2rUie3%2FRYGsr5vwlg%2BSPSPde0feh2%2BMFQwFNRnll0zQUiIQUUnPX81N07p5KKNXG8STi%2FBOWQHO%2FW%2FDOvBrPxWxKoH%2BFIrV65vuByWASNcNyEjIUtBM5kOca3ZGMdK2B7Up1sg56D%2BX%2FDYO0KN7GzAvitV8TCC%2F0xSrOxVpC4sNwzRyK2HkaqsjGqw%2Fg|ampidL_CLK|clp:2047675
> 
> ...


That's a no on both. They can't handle the voltage and they also have way too high internal resistance. Only use EL11 in the EL11 sockets.

Btw, I had first listen to Odyssey today! I have to say I'm really liking the sound! It sounds big and full! Lots of authority but very smooth as well! Tomorrow I'll make power measurements!


----------



## UntilThen

SonicTrance said:


> That's a no on both. They can't handle the voltage and they also have way too high internal resistance. Only use EL11 in the EL11 sockets.
> 
> Btw, I had first listen to Odyssey today! I have to say I'm really liking the sound! It sounds big and full! Lots of authority but very smooth as well! Tomorrow I'll make power measurements!



O M G..... don't worry about EF11... I'm now super excited about Odyssey. Sounds big and full !!!

I'm thinking this


----------



## hpamdr

OctavianH said:


> I've sold my Siemens C3g with Elise, but I still have a pair of Valvo EL11 and 3 pairs of Philips EL3N. So, why not, I'll think about it. I'll have to break my rule of "no adapter is best adapter" and this requires judgement and decision.


I've used 6J7, EL11 and  6Z49P-E / 6Z43P-E in Eternity ! 
6J7 give same type of sound as 6J5 the strapped pentode as triode euphonic is not present !
6Z49P (6J49) and 43 version gives very good result tube are built for 150V anode but woks at 180V.  
EL11 have the pentode flavor adding some harmonics to the sound which is very enjoyable specialy with Eternity as it is not as pronounced as Elise/Euforia.  
I will try EL3N when i will build adapter for it !

The EL34 Telefunken I have are like UT pointed, clear with some high extend I can place them between the Tesla EL34 and the EL12spez.

Today I've paired with Russian 6Н6П with same adapter as ECC88 to 6SN7 Mu at 180V is around 14 bias is at -15.5V for 4mA.
I like a lot the small double triode with EL34 on Eternity..


----------



## OctavianH

You've bought a box of those russian tubes? This is what I call investment.

I'll keep an eye on a pair of Telefunken EL34 and also fortify my stash of Tesla EL34 because from time to time you can find those at very good prices.


----------



## UntilThen

Octa, keep your eyes on these metal base.


----------



## hpamdr (Jul 17, 2021)

OctavianH said:


> You've bought a box of those russian tubes? This is what I call investment.
> 
> I'll keep an eye on a pair of Telefunken EL34 and also fortify my stash of Tesla EL34 because from time to time you can find those at very good prices.


I was part of a group buy with local fellows long time ago 100 pieces.... I just kept 6 tubes used at the time on garage hybrid amp ! _(the photo is not mine )_
About EL34 tubes you can get good rebranded tube for descent price but not the one pointed by U.T. those one cost like diamond on top of gold !
If you can get EL39 you should really test it !


----------



## OctavianH

hpamdr said:


> I was part of a group buy with local fellows long time ago 100 pieces.... I just kept 6 tubes used at the time on garage hybrid amp ! _(the photo is not mine )_
> About EL34 tubes you can get good rebranded tube for descent price but not the one pointed by U.T. those one cost like diamond on top of gold !
> If you can get EL39 you should really test it !


I know that the metal base are above my budget and I do not want to invest too much, because these Tesla EL34 are excellent. Being more harsh sounding and aggressive are somehow compensating the polite and forgiving signature of T1.2. The other pairs of EL34 I have are better technically but do not pair so well with this headphone.


----------



## OctavianH

Ok guys, let's have some fun. I told you a few days ago that I was looking for a light comfortable headphone which complements the Verite Open and can be used during summer. I was also telling you that T1.2 is a little bit off focus on Eternity, and even if I found a decent compromise for it, I felt something was not perfect. But we all know there is no perfect headphone, so we need to carefully choose different types which are complementing each other and obtain all the flavours we need.
So I decided to try the almost unknown Audio-Technica ATH-AWAS. Closed back, 40 Ohms, warm yet detailed signature. A musical and fun headphone.





This headphone has 395g without cable, the headband and earpads are synthetic leather, the headband is light and you barely feel it during summer. The earcups might not be better than the velour pads of T1.2 in terms of comfort but are still decent during high temps. But how is the sound? Well, this is a smooth sounding headphone, a mid centric one similar with T1.2 but not so veiled or sleepy as it was T1.2 on Eternity. It is warm, yet decently detailed, the high frequencies are quite delicate, much less fatiguing than on the Beyers (here I miss a little bit those because I got used with them) and the bass is present, punchy but of less quantity than on T1.2. What to say, a very interesting headphone, which has something special. I'll play with it in the next day and decide if I keep it or return it and try the bigger brother AWKT.





And a good thing is that AWAS sounds quite good on different tubes than the rest of my headphones. So, a little bit of diversity. I am quite enjoying some 6SN7 and KT88.
I know I am an awful describer of what I hear, but this review is excellent and tells exactly what I am missing to describe.


----------



## OctavianH

Continuing my journey with these ATH-AWAS. A very interesting headphone, tuned somehow for acoustic music from an analogue source, or at least this is how I perceive them. Slightly warm and energetic, a very dynamic headphone which is quite good on rock music because it is able to transfer the energy from the music to your ear. Less bass than all my other headphones, but more detail and focus than on T1.2, and being somehow brighter than the Verite, make some acoustic/vocal passages to shine. I paired it with my Forza AudioWorks Noir Mk2 copper cable which I still have from the times I owned the ADX5000 and put some more laid back tubes like Mullard EL34 xf2 with the GEC L63 grey glass. These add a little bit of weight on the signature, everything becoming quite emotional, if I might say. I really like what I hear and I think I'll keep these in my collection. They have something which no other headphone I had the chance to own or listen during the years was able to provide me: a combination of raw energy with intimate detail. Sounds crazy, but usually if a headphone has one, does not have the other or at least this is how I thought it was until I discovered these.





These are definitely not for electronic or modern music, but for jazz or classic blues or rock I would say, if they are paired properly, these might do the trick. I'll try them on the TT2 just for curiosity, but at the moment Eternity keeps me busy. They are not perfect, but always compensate with something else when I feel something is missing. Might be a quality to be able to provide me always something in exchange when I miss something else. I still have 12 days to decide but today they were a winner.


----------



## UntilThen

Eternity is looking good !


----------



## OctavianH

Yes, Eternity is a beautiful amplifier.


----------



## OctavianH

This is good for Friday:


----------



## OctavianH

Today is a sad day for me, a good day for science. After listening 3 days to the Audio-Technica ATH-AWAS which was very close to what I am looking for, I realized I cannot use it in my usage scenario of listening to 12-14 hours per day to music. And even if this scenario is not common, I think the most important thing is to listen to our music as long as we can, not to own expensive gear which reveals a lot but makes you tired after 5 hours of listening. AWAS was great, compensating exactly what I am missing on my other headphones but somehow not usable on my scenario. So today I returned them and decided to try also the Dan Clark Audio Ether 2, which after the recommendation of @UntilThen became very interesting for me. I read several reviews and I want to try it. I found a used but good condition pair in Europe and bought it, after a few weeks it will arrive here and I will be able to try Eternity with some very low impedance headphones, like the 16 Ohms Ether 2. Let's see what this will bring to the table.

Currently listening to something nobody ever listened on head-fi:



PS. In the meantime I wait to try some 6CA7. Won some very good auctions on Ebay and I'll soon try some. Good times ahead guys.


----------



## UntilThen

OctavianH said:


> So today I returned them and decided to try also the Dan Clark Audio Ether 2



I hope you like it.  It's Dan Clarke's top model. Light and airy in both weight and tone. Should be super comfy. I only had one audition of it with Ampandsound Encore. I remember holding it and thinking to myself that it is very light and well made.


----------



## OctavianH

UntilThen said:


> I hope you like it.  It's Dan Clarke's top model. Light and airy in both weight and tone. Should be super comfy. I only had one audition of it with Ampandsound Encore. I remember holding it and thinking to myself that it is very light and well made.


I have no idea if I'll like it but it is interesting enough to try it. If not, I'll assume 10% loss to sell them and I will remain with a very nice experience, hopefully. AWAS was great, much more than what I was expecting from a close back, but still I was not convinced to keep them. I am not a headphone roller, I just want to try some comfy headphones because I need something for the summer and long listening sessions and the T1.2 are in that area but their time is limited. The model is discontinued and my pair is old and the headband and earpads are not in perfect shape, I'll replace them but I realize that the headphone has to go some time in the future. So I look for a comfortable alternative which will be easy to wear and easy to listen on Eternity in times when Verite Open is too heavy. Verite Open will remain for me the "reference" headphone.


----------



## UntilThen

The DCA Ether 2 is 293 grams while my LCD4 is 708 grams. Just to give you an idea of the weight difference. One reviewer sums it well with a description of 'open, transparent and spacious'. I'm really intrigued by it because it's very different to what I've experience before. I live with Verite LTD Open for more than a year so I know that signature very well and I sold the LCD3 because of it. I know now never to dismiss a headphone after a year because your preference can change, especially when you change your gear.


----------



## OctavianH

I fully agree. This is the reason I decided to try the Ether 2 because it is incredible light, but still has some very nice comments and reviews, it is something I have to try. If I'll like it I will be able to say in around a month. I will keep Verite Open for my main listening sessions, I was able to get an Empyrean at a good price but I do not really think I need it, what I need is a light headphone and Ether 2 might do the trick. At the moment for 3 weeks I use T1.2 and it is quite OK for what I need.


----------



## UntilThen

My headphone quota is 2 or max 3. I had He1000se only January of this year and LCD4 is only 3 months ago. The same with my 300b amp. I'm still enjoying them you could say. In fact, I'm very content at this stage but I know that I'm already tempted with the Abyss 1266 TC, which I will be getting a home demo pair once lockdown is lifted. Now the Abyss is not a headphone that you want to wear for 12 to 16 hours.  Neither is the LCD4.

In fact I could not wear a headphone for more than 8 hours now. 6 hours is probably max but who knows when Odyssey comes.  

However I also want to try Susvara with Odyssey and I cannot find a home demo pair.  I might have to bring Odyssey to Minidisc. Nah...no way I will carry that amp all over. I expect it to be at least 20 kgs.


----------



## OctavianH

I know, my usage scenario is a little bit strange. I work in the software industry and I have some quite long listening sessions. While I am in some meetings I keep my amplifiers on, but usually at least 6 hours I get per day, sometimes much more. It is an advantage or a disadvantage, I have no idea, I just know I need a comfortable pair of headphones to use all day long.
I have 2 pairs of headphones at this time: T1.2 which I own for many years (my second pair actually) and Verite Open which I own for around 1 year. T1.2 will have to go in the near future, so I want to replace it with something light, yet detailed, to be able to wear all day long and during summer when temps are high. With Verite Open I was sweating during summer under the leather headband. I need something lighter, as an alternative. Plan is to own only 2 headphones in the near future.


----------



## OctavianH (Jul 23, 2021)

Back to music, after I listened to the latest Necrophobic album and I remembered their show at Wacken 2019 which was the latest open air I have attended I have decided to go back to older stuff.



Honestly these guys were incredible, a lot of energy and a quite decent show. I wonder what are eating these guys in Sweden to be able to provide this energy after all these years.

Now back to more older stuff, Children of the Sea:


----------



## UntilThen

My contribution for this morning. I was searching for 'Imagine' because that's what was played at the opening ceremony of the Tokyo Olympics. Nothing was on Youtube yet but there's Emmanuel singing with Coldplay instead. I was listening with LCD4 powered by Destiny and I'm sure John Lennon would have approved.


----------



## OctavianH

UntilThen said:


> My contribution for this morning. I was searching for 'Imagine' because that's what was played at the opening ceremony of the Tokyo Olympics. Nothing was on Youtube yet but there's Emmanuel singing with Coldplay instead. I was listening with LCD4 powered by Destiny and I'm sure John Lennon would have approved.



I quite like your song and this reminds me about my trip to Prague. Prague is a beautiful city which has a John Lennon Pub.










If you visit Prague, try it, quite nice.


----------



## UntilThen

What the... a John Lennon pub. He would have been proud ! If I could one day visit Prague.


----------



## OctavianH

UntilThen said:


> What the... a John Lennon pub. He would have been proud ! If I could one day visit Prague.


The "lockers wall" from the first picture is a bridge, if I remember correctly, which leads to the pub. Those are the lovers markings, many lovers in Prague it seems or at least many who travelled there. The pub is nice, it has the "Yellow Submarine" in several places, I had some snacks and a few beers there, only Beatles music, a nice place.


----------



## OctavianH

And since I've started to listen to Black Sabbath with Dio I cannot miss the Sign of the Southern Cross:



I remember seeing Dio in 2009 before his passing. I cannot say how much I've felt it.


----------



## OctavianH

And if we are in "Gods area" why not listen to some Perfect Strangers live France:


----------



## triod750

OctavianH - you are a true lover of music yourself! I can see your lockers all over youtube. And what could be more appropriate than a hard rocking amp from Sweden? Just Imagine!


----------



## UntilThen

triod750 said:


> OctavianH - you are a true lover of music yourself! I can see your lockers all over youtube. And what could be more appropriate than a hard rocking amp from Sweden? Just Imagine!



Yeah I can't keep up with his metal heads ! Now Odyssey will be the hard rocking amp from Sweden.


----------



## OctavianH

Ah, this weekend Odyssey will be finished. So we will have pictures.


----------



## SonicTrance

OctavianH said:


> Ah, this weekend Odyssey will be finished. So we will have pictures.


That was the plan! It's not going to happen though. That's because I've, mistakenly, ordered the wrong switches for Odyssey! Was going to start wiring them up yesterday evening when I noticed it.. It's very frustrating! (for me, @UntilThen is cool fortunately  So, further delay on Odyssey. 
I'll give you a peek on the somewhat completed amp though!


----------



## OctavianH

Wow, that looks quite gorgeous.


----------



## Magol79

Very nice! Clean and classy. Nice work.


----------



## UntilThen

Omg Bcowen get me a drink please. I'm seeing Odyssey in the flesh with Sowter output transformers.


----------



## UntilThen

SonicTrance said:


> That was the plan! It's not going to happen though. That's because I've, mistakenly, ordered the wrong switches for Odyssey! Was going to start wiring them up yesterday evening when I noticed it.. It's very frustrating! (for me, @UntilThen is cool fortunately  So, further delay on Odyssey.
> I'll give you a peek on the somewhat completed amp though!



No worries Tomas. It's hard to visualize how Odyssey will turn out when we discuss at the beginning using the silver chassis but I'm more than pleased, seeing it now. The Sowter output transformers blend in with the Hammond mains transformer.


----------



## SonicTrance

OctavianH said:


> Wow, that looks quite gorgeous.





Magol79 said:


> Very nice! Clean and classy. Nice work.


Thanks guys!  



UntilThen said:


> No worries Tomas. It's hard to visualize how Odyssey will turn out when we discuss at the beginning using the silver chassis but I'm more than pleased, seeing it now. The Sowter output transformers blend in with the Hammond mains transformer.


Yes! The endbells we got for the Hammond mains tranny is exactly the same as the Sowters. It's a perfect match! I'm glad you like it!


----------



## UntilThen

Tomas, can Odyssey use this KT170 ?


----------



## SonicTrance

UntilThen said:


> Tomas, can Odyssey use this KT170 ?


Yes, you can. It's at the upper limit of what the heater supply can handle but still ok. You got 6A total of heater current.


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## OctavianH (Jul 25, 2021)

Hmm, Yngwie Malmsteen has a new album. Interesting! Eternity, we have stuff to do.



This album would have been very good on AWAS with that incredible tuning for guitars. But AWAS is gone now, we have to deal with what we have.


----------



## UntilThen

SonicTrance said:


> Yes, you can. It's at the upper limit of what the heater supply can handle but still ok. You got 6A total of heater current.



Alright. It's AUD$420 a pair. As much as a pair of Genalex Gold Lion 300b tubes.


----------



## UntilThen

Elekit TU 8200 arriving today. Out of action for 2 to 3 moths.


----------



## SonicTrance

UntilThen said:


> Elekit TU 8200 arriving today. Out of action for 2 to 3 moths.


Congrats!


----------



## OctavianH

UntilThen said:


> Elekit TU 8200 arriving today. Out of action for 2 to 3 moths.


You found the problem with the 807? Will you try them again on it?


----------



## UntilThen

OctavianH said:


> You found the problem with the 807? Will you try them again on it?



Never found out the real problem. Could be tube but it's a new pair. When I told my supplier about it, he was very apologetic and surprised ! Said he tested the tubes before he send it to me. In return he gave me a new Sylvania 807. I won't use 807 in the amp again because I want to play it safe and not damage it on the 1st day it came back to me.   Besides I have so many other power tubes so why just obsessed with 807.

The fact Tomas told me to use 807 in Odyssey with 5U4G which has a lower voltage drop may be the clue. 

However, I received the 8200 today and I was so eager to try it especially when Jules did not listen to it with headphone. I had inserted very simple current production Psvane 12au7 and EH 6L6GC tubes. Very gingerly I powered it on. Blue power light came on and tubes lighted beautifully. I plug in my He1000se. If it blows, I can kiss my HiFiMan goodbye.  With no music playing, there was absolute zero noise, even when I turn the volume to max. Jules must have done something right ! He replaced with Mundorf caps, some resistors and of course the FET. Even left me a bag of FETs. Said he had to order a whole bunch. They don't sell single or 2 or threes FETs.

Anyway, I selected my music and press play. The next few seconds was one of astonishment. I have never heard the TU-8200 sound so good. The tone is amazing. I was more than impressed ! So what happened in the interim of 2 to 3 months. I don't really know. Over the next few days, I'll roll in other driver and power tubes and also compared it again to Oblivion and Destiny. I had initially wanted to repair the 8200 and then sell it but I won't now. It even drives speakers amazingly well. Now I really look forward to Odyssey arrival so I can compare it to the 8200 because it uses similar power tubes.


----------



## UntilThen

To say that I love this pair of KT88 is an understatement. Can't wait to try it in Odyssey. Anyway have to cut short the listening enjoyment as I have to go out for dinner. To be continued.


----------



## OctavianH

I am very glad that you consider these Psvane KT88-T2 so good. I also consider them exceptional. I've had the chance to listen to some Ayon KT88 (manufactured in China for Ayon amplifiers) and also the russian reissue of Gold Lions KT88 and honestly, for me these Psvane are above both others.


----------



## UntilThen

The magic continues with Tung Sol 6550 and Shuguang Treasures KT88. I discovered that my Brimar 12au7 long plates are the culprit for the static, hissing sound I get on the left channel. Which is a shame as the pair of Brimar is NOS NIB. When I switched to Psvane 12au7, it is quiet.

I'm prepping the tubes for Odyssey.


----------



## OctavianH

Found a pair of Sylvania 6CA7 matched 5%. This is rebranded MESA STR416.






It is also quite strong, stronger than my EL34 pairs which are around -15.5-16.5V:





At first I thought this is an american EL34 equivalent and has to sound the same, BUT I was wrong. 6CA7 does not sound the same, it has a very special and refined sound combining KT66 + EL34. I like this:





I am quite impressed about these. 6CA7 has a chance to become one of my favourite types.

And in the end, I finished my stash of Tesla EL34, which I found very cheap compared to what they provide, in years these will go up a lot, the double angled getters:





Now all I have to do is measure and match and enjoy.


----------



## UntilThen

Sylvania 6CA7 fat boy are different from Philips Miniwatt 6CA7/EL34. Fat boy can also be branded GE or RCA. I will get a pair of Fat Boy to try for myself.

Meanwhile once I've selected a pair of quiet Psvane 12au7 drivers, all power tubes I roll in now are just so quiet. That makes me very happy. It's the Philips Miniwatt 6CA7 in the power slot now.


----------



## OctavianH (Jul 27, 2021)

UntilThen said:


> Sylvania 6CA7 fat boy are different from Philips Miniwatt 6CA7/EL34. Fat boy can also be branded GE or RCA. I will get a pair of Fat Boy to try for myself.


It is my first time I hear 6CA7. I like these a lot. I'll get another pair at a cheap price, Shuguang Black Treasure Z 6CA7 and compare them.

Later edit: While reading several guitar amp forums I saw an interesting comparison for Sylvania "fat bottle" 6CA7: a combination of 6550A + 6L6GC.


----------



## UntilThen

Tested 3 more pair of power tubes. They are all quiet and sound incredible. I can't wait to try them in Odyssey. As I said before, Elekit TU-8200 is the test bed for my tubes.  

GEC KT66


Shuguang Treasures KT88 Z


Tung Sol 6550 1960s


----------



## OctavianH (Jul 27, 2021)

UntilThen said:


> Shuguang Treasures KT88 Z


How are those Shuguang Tresures Z? The 6CA7 I'm receiving are similar.





In the meantime I start to burn in my perfect pair of Tesla EL34 double angled getter. I made measurements today and made 2 perfect pairs (less than 1mA between) and one decent pair (2mA). 2 are unmatched, candidates for future pairing. These Tesla EL34 are incredible, for me are better than the Mullard xf2. I am glad that I made my stash, now I do not care anymore about the prices.

The angled getters:





These tubes are selling rebranded as Edicron EL34 for less than 50 EUR/piece and for me are absolutely incredible. The Mullard xf2 are laid back and refined, but these have better treble and almost the same bass, with a little bit of harshness in the mids, however, for me and T1.2 these are perfect. For the price, absolute winners.


----------



## UntilThen

OctavianH said:


> How are those Shuguang Tresures Z? The 6CA7 I'm receiving are similar.



Might be what you're after. More laid back than Gold Lion or Psvane KT88. The term laid back is only use here to compare with the other KT88 types because you can never accuse the KT88 of being laid back. 

EL34 is more relaxed than KT88. Relax is a term I rather use than laid back because even EL34 is not laid back. It's just more relaxed and comforting.

I'm still listening with GEC KT66. This is a beautiful tube in Elekit TU-8200 with He1000se but so are the other power tubes. With the 6as7 / 6080 types, I know straight away what the different variants sound like but with KT88 / EL34 / KT66 / KT77, I'm still coming to grips with it but I certainly prefer the latter group of tubes (KT88 / EL34)  for their dynamics, punch and bigger and more powerful sound signatures.


----------



## triod750

UntilThen said:


> Might be what you're after. More laid back than Gold Lion or Psvane KT88. The term laid back is only use here to compare with the other KT88 types because you can never accuse the KT88 of being laid back.
> 
> EL34 is more relaxed than KT88. Relax is a term I rather use than laid back because even EL34 is not laid back. It's just more relaxed and comforting.
> 
> I'm still listening with GEC KT66. This is a beautiful tube in Elekit TU-8200 with He1000se but so are the other power tubes. With the 6as7 / 6080 types, I know straight away what the different variants sound like but with KT88 / EL34 / KT66 / KT77, I'm still coming to grips with it but I certainly prefer the latter group of tubes (KT88 / EL34)  for their dynamics, punch and bigger and more powerful sound signatures.


But you are comparing OTL with output transformers now, aren't you? Not only the tubes?


----------



## UntilThen

triod750 said:


> But you are comparing OTL with output transformers now, aren't you? Not only the tubes?



Nope. I use 6as7 / 6080 in Wa22 and that's transformer coupled not OTL.


----------



## UntilThen

The only 2 OTL that I feel have enough grunt and power are the La Figaro 339i and GOTL with 6 x 6bx7gt configuration.


----------



## OctavianH

UntilThen said:


> Might be what you're after. More laid back than Gold Lion or Psvane KT88. The term laid back is only use here to compare with the other KT88 types because you can never accuse the KT88 of being laid back.


I have a feeling those are similar with Ayon KT88. Here is an old picture, in 2019 when I last tried them. As far as I know those were manufactured by Shuguang for Ayon to sell with their amplifiers and your sound description matches what I remember.


----------



## UntilThen

It’s probably the same except my pair has a silver metal base whereas yours is gold.


----------



## OctavianH

Yes, I bought them from someone who owned an Ayon speaker amplifier and upgraded to KT120. So he sold these at a basic price to get rid of them. There is an article about these on a polish website here. I will put here an excerpt:



> Maybe it was meant to be so, although I am not a fatalist. Just a few days before our guest’s visit I received tubes from Ayon, the KT88sx – a brand new product of Gerhard Hirt. I knew something was cooking because I reviewed the Orion II amplifier which used the KT88s, a Chinese product modified by Gerhard, sold with his company logo. I asked about his plans and it turned out that the KT88s will only be used in the basic Ayon amplifier; the more expensive ones will use completely new KT88sx tubes instead of the KT88 Shuguang Black Treasure. The KT88sx is a development version of the Black Treasure, designed according to Gerhard’s plans and manufactured by Shuguang. And the Austrian has vast experience in making vacuum tubes.
> And here they are, beautiful, brilliantly made KT88sx Ayon Audio. Their sockets are made from gold plated metal, just like the pins. The glass is covered with carbon particles (Shuguang talks about a polymer alloy) to help with focusing the electrons in the anode. Another material used in their construction and called Super Alloy helps maintaining the tubes electrical parameters for prolonged period of time. It took three years to develop this technology and Shuguang is probably the biggest company in the world manufacturing vacuum tubes. You can find 65 differences between their tubes and KT88 from other companies. Gerhard made sure that there are even more of them…


----------



## UntilThen

Sound impressive. I almost bought the Shuguang 300b tubes.  

Rolling in the RFT EL34 tonight. Another quiet pair. When it's quiet in the tube amp, it's like heaven. There's a sweetness and euphony from the EL34 and variants. 

A little about RFT ...

RFT stands for Rundfunk- und Fernmelde-Technik - a group of state-owned technology companies in the former German Democratic Republic (East Germany). This company produced valves for Telefunken and Siemens and made the famous Siemens EL34. These valves are of very good quality and have excellent consistency.


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## OctavianH (Jul 29, 2021)

Shuguang 6CA7 Black treasure, wam, full, forgiving but still soemhow similar with the other pair of 6CA7 I tried. I like these for a warm forgiving signature, with more neutral inputs. But the bass is not as tight like on EL34, they compensate somehow on mids which are sweeter, if you prefer that kind of sound (reminding on KT66). Another disadvantage for me would be a little bit of recession in the high frequencies area, I always liked clean detailed highs.









I found these used in Germany, matched by Tube Amp Doctor. I have to say are perfectly matched (less that 0.5mA). The build quality is not as impressive as on the Psvanes KT88 which are heavier and have that ceramic base dressed in aluminium, these look cheaper, but glow nice and are light as a feather.


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## OctavianH (Jul 29, 2021)

Going back to the Sylvania 6CA7 "fat bottle" I realize I like these more than the Shuguang 6CA7 Black Treasure Z. But my reasons are subjective up to a point. I still use the Beyerdynamic T1.2 which are headphones much more suitable to more neutral, detailed and with extended highs tubes. Thinking that last week I was listening to AWAS, those headphones were much more in need of a warmer and relaxed signature like the chinese ones have. And we have to think also about the price difference, the new ones being cheaper than the NOS ones. As usual, the older, the better, and as someone said, the "fat bottle" Sylvanias are different than the usual 6CA7. Well, different but very good.






I read a little bit about them, mine are double getters like here. A lot of nice pictures, postcards and nice stuff on this link. I hope you'll enjoy it as much as I do.

Listening to Revolution from the new Heavy Water album, Red Brick City, a combination of rock, alternative and some blues (my own assessment, I have no idea in what genre they call themselves), these sound incredible:


----------



## OctavianH

Thank you for the music!


----------



## UntilThen

Octa, good observation there in recognising that when sampling tubes, headphones and system setup will influence preference. That is the reason for tube rolling. We're trying to tailor the ideal sound for our own unique system. 

That and also our ears and brains. We're all wired differently.  I'm pretty sure I'm single ended triode and not push pull.


----------



## UntilThen

OctavianH said:


> Shuguang 6CA7 Black treasure, wam, full, forgiving but still soemhow similar with the other pair of 6CA7 I tried. I like these for a warm forgiving signature, with more neutral inputs. But the bass is not as tight like on EL34



I'll just comment on this statement of yours. Surprisingly I had the same thoughts when I switch from Genalex Gold Lion KT77 to RFT EL34. The latter wins here for me because the East German EL34 has that sweet treble and tighter overall sound, especially in the bass region.

My Philips Miniwatt 6CA7 (it's really a Mullard EL34 - in the same sound signature I'm pretty sure) is more expensive than the RFT EL34 but I'm liking both at this point in time. When I get the Philips Miniwatt double D getters brown base and metal base, then I'll evaluate the different EL34s. Again in the context of my system.

My supplier told me that the reason he wouldn't sell me the GEC KT77 is because when he tried a quad of GEC KT77 in his Leak amplifier, it sounded better than even the EL34 metal base. No amount of persuasion now will make him sell me a pair. Well he only has a quad and he needs them in his amp.


----------



## UntilThen

I'm just curious about RFT EL34 and Tesla EL34. They're both East Germans tubes. Do you have both? How are they different. I think I have to get myself a pair of Tesla EL34.


----------



## triod750

UntilThen said:


> I'm just curious about RFT EL34 and Tesla EL34. They're both East Germans tubes.


It's my understanding that Tesla EL34 was manufactured in Czechoslovakia, not East Germany.


----------



## UntilThen

triod750 said:


> It's my understanding that Tesla EL34 was manufactured in Czechoslovakia, not East Germany.



Oh my bad 😀


----------



## triod750

UntilThen said:


> Oh my bad 😀


Be my guest.


----------



## mordy

My next tube, I mean car, is going to be a Tesla.


----------



## UntilThen

mordy said:


> My next tube, I mean car, is going to be a Tesla.



Yup that’s a nice e-car. A friend here got one. I think it’s about $70,000 plus Aussie dollars. 😀


----------



## mordy

Waiting for the price to come down - the least expensive here in the US are around 40K.


----------



## OctavianH (Jul 30, 2021)

UntilThen said:


> I'm just curious about RFT EL34 and Tesla EL34. They're both East Germans tubes. Do you have both? How are they different. I think I have to get myself a pair of Tesla EL34.


No, I do not have any RFT. And yes, GEC KT77 are the best, no EL34 is a match for them, at least for me.

Later edit: Some words about Tesla EL34. 

The prices are misleading on Ebay, the ones branded as Tesla are quite expensive, others identical can be found as Edicron EL34 or even Marshall. The ones I have all all Edicron EL34 found in Germany for less than 50 EUR/piece. All have brown base, double angled O-getters and sound the same, even if I have 2 date codes on them and I cannot decypher (E9LP8 and G9LP8). The brown base has some small differences, some of them look to me darker and some of them brighter (the colour) but the internal construction is the same. I like them more than the Mullard xf2 if you can imagine, because they have a decent bass, close to mullards but better extension on high frequencies which make them more "balanced" for me. I have no golden ear but for me those are better. Now, on Ebay:




I looked to the pictures and that quad is identical to my Edicron EL34 and the price is around 100 EUR/piece. The one above is similar, and it is 20 EUR.

And some Marshall, all double angled O-getter:





What to say, you need to make a small research to find these at a decent price, which is for me, around 40 EUR/piece.


----------



## OctavianH (Jul 30, 2021)

Ok, and because some pictures make more than 1000 words, I made some pictures at 2 of my Tesla EL34 bought rebranded as Edicron.
Here you can see that they have the same construction, you can also see small differences in the brown base colour:




The one from left has E9LF8 date code and the one from right has G9LP8. If the first letter is a year, it might be that these have been manufactured at 2 years distance? (E-F-G). I have no idea, just guessing. Two days ago while listening to these I had a feeling that the left one has better bass than the other, but on normal music you cannot see the difference. So I tried with this youtube video:



It's definitely not a very scientific test, next would be to put them reversed in the amplifier (move the left one to right and vice versa). If the difference would still be heard, in this case on the right channel, I'll make another test, with pairs matched with date, like 2 x E9LP9 and 2 x G9LP9 just to see if indeed, there is a difference in sound. However, it is like 10% let's say, a little bit of harder kicking, so most probably I am crazy or my right ear has a small different perception.


----------



## UntilThen

Left side sounds louder. It's a dud video.


----------



## OctavianH

UntilThen said:


> Left side sounds louder. It's a dud video.


Ah, I have to say I thought about this also. Thanks! Then, identical sound on both tubes.


----------



## UntilThen

OctavianH said:


> Ah, I have to say I thought about this also. Thanks! Then, identical sound on both tubes.



Ask Bcowen to listen. He has sharp ears.


----------



## OctavianH

UntilThen said:


> Ask Bcowen to listen. He has sharp ears.


I guess these guys are the best audiophiles around here, judging by ears:


----------



## UntilThen

That’s Bcowen family.


----------



## OctavianH

Hmm, I took my bow and went hunting for some RFT EL34, if I find them at my price range, I'll compare them with Tesla EL34.
In the meatime I think I'll sell some 6SN7/6AS7 because I do not need them. Or I need them? Hmm.


----------



## OctavianH

I found a good pairing of the Sylvania 6CA7 with the GEC L63 grey glass. I like a lot this pairing and it is by far the best one for T1.2, somehow tightens all frequency areas and makes them sound better than on all others I've tried. Good catch these.




The 6CA7 is an interesting flavour and it cannot be ignored on Eternity, it has its own identity and might be useful for specific setups.


----------



## UntilThen

OctavianH said:


> Hmm, I took my bow and went hunting for some RFT EL34, if I find them at my price range, I'll compare them with Tesla EL34.
> In the meatime I think I'll sell some 6SN7/6AS7 because I do not need them. Or I need them? Hmm.



Don't get rid of the 6sn7 and 6as7 so quickly. I regretted selling off some of my 6sn7. Could have use them now on Odyssey. Like the mint Sylvania 6sn7w metal base, Mullard ECC33 and ECC35. Selling off the GEC 6as7g pair was also a mistake and also the GEC U52 rectifier. Priceless now.


----------



## UntilThen

In the early stages of Odyssey design, I had a choice of EL11 or 6J5 / L63 as drivers. Decided to go with EL11 because I have only one shot at getting a custom amp build for those tubes as drivers and using those Yamamoto's sockets.


----------



## OctavianH

Well, you might be right even if I never listened to any 6SN7 and 6AS7 in my last year with Elise. There are better options and Eternity can use them, basically this was the reason I wanted Eternity.


----------



## OctavianH

The Sylvania 6CA7 kept me busy all the weekend. I cannot replace this for T1.2, it makes wonders to these headphones.





It is an exceptional all rounder, providing a middle way for both good produced and bad produced records.


----------



## OctavianH

What do we have here?


----------



## UntilThen

Oooo yeah. You will enjoy it with Eternity.


----------



## OctavianH (Aug 4, 2021)

UntilThen said:


> Oooo yeah. You will enjoy it with Eternity.


I am still discovering and trying to understand these headphones. They are, for sure, very interesting but also very different than my other pairs. I have to admit that I bought them from curiosity, finding a pair of headphones around 300g with 3 sets of earpads and that interesting system of exchanging them fast (peelable earpads) was a decision factor. Now, we will see where this goes, what I can say now is that:
- they are light and comfortable, but might not be for anyone, if you have a Sponge Bob head look elsewhere, also if you are an Elf, so depending on the shape of the head and the size of the ears these might not be for everyone. In my case, I never had problems with Beyerdynamic T1.2 which many considered they have small earpads. Another problem might be with the clamp force, but for me that is also fine, a little bit on the tight side but I'm sure this will adjust
- the earpads are dramatically adjusting the sound, for me they are quite at the level of tube rolling, and the swaping mechanism is simple, in 5 minutes you have new earpads without worrying too much or needed any kind of skills
- the cable is flexible, not microphonic, not as good as the T1.2 Cardas one but it is better than what I have received with my previous Sennheiser, Audio-Technica or ZMF headphones (here I heard they upgraded for Verite the cable, I received the older version)
- build quality is top class, looks sturdy and reliable
- now, about the sound, I do not have an opinion yet because I am in the process of discovering it, it is not a warm headphone, but somehow has a darker nature, the high frequencies being a little bit rolled off, or presented in a "delicate" way so most probably many others might consider them rolled off. And I have a feeling that these are evolving, or at least I am evolving in getting used with them, so I am convinced my opinion will change in time. We will see in around 100 hrs, I am in no hurry since I cannot return these, if I'll decide I do not like them I'll have to sell these.

At first I was recluctant to 16 Ohms headphones, I have no idea about Eternity's output impedance, but Tomas assured me it is very low, so the rule of "eight" which I know has to apply to match a headphone to an amplifier has to be fine. Anyway, I can try these on another 2 amplifiers, TT2 and a cheap one I still  have around, audio-gd NFB11.28 which is rated at 15-600Ohm.


----------



## UntilThen

Dan Clarke Audio Ether 2 may be unique but it's not for me. I'm very selective of the headphones I want and I want no more than 3. Not counting the HD800 and HD650.  
I settle on He1000se and LCD4 because I like those 2 tonally and they are contrasting. The next and last headphone will be audition first. That's the Abyss 1266 phi TC. I am not sure if that's for me but we will see.


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## OctavianH (Aug 4, 2021)

I have no idea if it is for me either, but I know that I do not want to buy other 500g+ headphones with full wide leather headband. My Verite Open is great, but I am not using it for one month because of the heat in summer. In my long listening sessions I start to sweat because of it. Empyrean might be nice with a different headband, something synthetic or perforated. I will try and search until I will find a headphone suitable for me, we will see which one will be.

A little remark on serviceability and a short story:

My pair of T1.2 is old, pleather headband dissintegrates and leaves small pieces of black pleather on your hand/head. Velour earpads are also weared because I wear a beard. No problem, I have a replacement headband of real leather (bought for T1.1 but compatible) and also a replacement pair of earpads. But if you look into T1.2 service manual to exchange them, well, the earpads might be simple (even if I am sure it cannot compare to ZMF or DCA) but the headband, well, is doable with a percentage of risk. Well, headband on DCA seems interchangeable via 2 screws:




Also the headband secure mechanism can be adjusted from there. I haven't tried, but I'll have to do this soon for the Beyers. What to say, I like simple things and reusable and serviceable things. These give you confidence that you will be able to repair something. Well, now try this with your mobile phones which cost the same as this one. LOL


----------



## OctavianH

Already 12 hours of listening to DCA's Ether 2. I've put the Mullard EL34 xf2 because those have the best bass from all my pairs and also the Fivre 6N7G which has a warm tone and also extends a little bit the soundstage having a more airy presentation. With the stock pads these headphones sound quite tight and this tight sound needs a little bit of air to become enjoyable. The reason to use this combo is that yesterday I had a feeling that these are a little bit light in bass. Well, today I feel them to be quite warm, a darker tone and I have a feeling that soon I'll want to reduce the bass quantity. My question is if these change so much in only 12 hours or my brain is able to adjust so much. I never had such an experience with other pair of headphones, where things were more or less like in the beginning with some evolving in some areas. Here, the change is dramatic and I have no idea if it is me or them.





During my long listening sessions, it is hard to follow each album and each track and make assessments to each of them. I follow a very unprofessional way of letting myself listening to the music for hours and then, at the end, trying to find a conclusion. Well, I am a little bit confused about the very different presentation of these headphones, but I quite like what I hear now. These have that darker sound which is a little bit immersive, it grows on you. While waiting for delivery I read the whole Ether 2 thread and many were claiming about this. Well, now I am experiencing the same thing. But these are not as fast as expected, compared to what planars shoud be, I do not feel incredible fast sounding headphones, what I feel is an organic sound, bold and quite well articulated. It might be the consequence of this darker tuning, audiophiles have to know more not me. I do not care about octaves, fancy words or measurements, I just want my music to sound good. And these are quite promising in that area.


----------



## OctavianH

Wanting to get a little bit of that tight dark area, I went again for the Tesla EL34. I told you guys many times about how good these are, at least on Eternity. The bass is not as tight, we receive a boost in the high frequency area. Exactly as expected, so my tubes behave somehow similar, and I know them. Now I can add my condiments in my cooking recipe and obtain the flavour I want, the only unknown variable is the Ether 2 but I start to decypher it.






Now I just have to listen to music, have a nice cold white beer from Mannheim. Germany, and wait. I will keep these, I am more and more sure about that. They do not check all the possible boxes, but they check more than others. Now, my rule is to have 2 headphones, and it is hard to sell any of the others, Beyerdynamic T1.2 being one of my all time favourites and ZMF Verite Open being the best of all three, in terms of sound. Comfortwise, DCA Ether 2 rules and closely followed by the Beyerdynamic T1.2. My listening session started today 11 hours ago because I had to work today. So, I guess I'll keep all three, I have time to decide until Ether 2 reaches 100 hours. That is my self imposed deadline.


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## OctavianH

Not sure about others, but I evaluate gear in a very personal way. Others measure, test with the same tracks or do some voodoo. I am not that kind, I am not burning in during night with noise or stuff, I am just listening to music. But I listen a lot, tens of hours, hundreds, all the time. Sometimes I dream about songs while not listening, so in my brain the listening experience is 24/24. And for every new piece I try my final test: the first Black Sabbath album.





For Ether 2 after I put my Tesla EL34 I went for the thing which makes me understand: Wicked World! If the guitar of Tony Iommi and the drums of Bill Ward are ok, I am ok. On the third place in this song comes Geezer Butler. Because the bass usually sounds good. And latest Ozzy. But if all are good, I am good.


----------



## UntilThen

OctavianH said:


> Already 12 hours of listening to DCA's Ether 2. I've put the Mullard EL34 xf2 because those have the best bass from all my pairs and also the Fivre 6N7G which has a warm tone and also extends a little bit the soundstage having a more airy presentation. With the stock pads these headphones sound quite tight and this tight sound needs a little bit of air to become enjoyable. The reason to use this combo is that yesterday I had a feeling that these are a little bit light in bass. Well, today I feel them to be quite warm, a darker tone and I have a feeling that soon I'll want to reduce the bass quantity. My question is if these change so much in only 12 hours or my brain is able to adjust so much. I never had such an experience with other pair of headphones, where things were more or less like in the beginning with some evolving in some areas. Here, the change is dramatic and I have no idea if it is me or them.
> 
> 
> 
> During my long listening sessions, it is hard to follow each album and each track and make assessments to each of them. I follow a very unprofessional way of letting myself listening to the music for hours and then, at the end, trying to find a conclusion. Well, I am a little bit confused about the very different presentation of these headphones, but I quite like what I hear now. These have that darker sound which is a little bit immersive, it grows on you. While waiting for delivery I read the whole Ether 2 thread and many were claiming about this. Well, now I am experiencing the same thing. But these are not as fast as expected, compared to what planars shoud be, I do not feel incredible fast sounding headphones, what I feel is an organic sound, bold and quite well articulated. It might be the consequence of this darker tuning, audiophiles have to know more not me. I do not care about octaves, fancy words or measurements, I just want my music to sound good. And these are quite promising in that area.



Nice picture. You do need time with a new gear, especially a headphone. I had just one listening session with Ether 2 on the Kenzie Encore and that's right after the Meze Empyrean. However that one short session pique my interest. Holding the headphone in my hands and the tone. It's very new for me but it left a nice impression on me.

The other thing is I listen to it with the Kenzie which is the poor man's 300b amp and the tone is warm and dark. Kind of match there.


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## OctavianH (Aug 5, 2021)

UntilThen said:


> Nice picture. You do need time with a new gear, especially a headphone.


You are right.

Later edit:
To avoid too many spam posts, even if I am the spam king here I'll edit and post this in this already existing one.
There is a strange feeling with these Ether 2, something I haven't experienced with other headphones. When I put them on my head after a break I have the feeling that they are somehow dark tuned with highs rolled off, after a few minutes of listening, I am somehow taken by this sound and I do not feel the same anymore and these seem warm but balanced. After another break this happens again. Strange is our brain.


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## OctavianH

What's more fun than tube rolling? I'll tell you, pads rolling. And the Ether 2 System comes with 3 sets of pads: Standard, Perforated and Suede. All change the presentation by quite a margin. So now you have 2 levels of tweaking, tubes then pads. Another variable in the equation, another possibility to have fun. And to make things worse I've ordered a Forza Noir Hybrid cable. Pad rolling is extremely easy, you just need 2 minutes because the pads have some "sticky" material inside and glue themselves on the carbon of the driver surface and they claim this works for hundreds of times. If the sticky material is not sticky anymore, just some alcohol and will work. I have my doubts, but I am sure 10-20 times will work until I'll understand these.


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## SonicTrance

Try pad rolling on Audeze headphones! They have the worst mounting system, 3M tape! Not reusable, lol.


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## UntilThen

That's the thing I hate about Audeze. Changing pads. Abyss has a very good system.


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## OctavianH

I know Audeze glues them, I have no idea why. If you look in the Classifieds for used Audeze, you see a lot with the pads damaged. I look from time to time on Classifieds not to buy stuff, but to learn faults about stuff. A very educative activity on head-fi. However, ZMF are good at this, pads are nice, provide a changed signature and are easy to replace. One thing I do not like at ZMF, after some time they start to rotate on the headphone.


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## OctavianH (Aug 11, 2021)

I have observed that I prefer these Ether 2 with 6SN7/7N7/6F8G instead of 6J5/6C5 in the input sockets. This does not mean those are not pairing well, but somehow I find a better combination which checks more boxes with these. No problem, I have plenty from my Elise years, and the good part is that I need here only 1 piece. So I have backups for almost all of them.





After some RCA 7N7 some Ken-Rad 6F8G. Both good pairs for Sylvania 6CA7.


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## UntilThen

OctavianH said:


> I have observed that I prefer these Ether 2 with 6SN7/7N7/6F8G instead of 6J5/6C5 in the input sockets. This does not mean those are not pairing well, but somehow I find a better combination which checks more boxes with these. No problem, I have plenty from my Elise years, and the good part is that I need here only 1 piece. So I have backups for almost all of them.



That is the beauty of Eternity and Odyssey. They only need one good double triode tube. Imagine buying a pair of Mullard ECC32 now. It's more expensive than ginseng !


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## OctavianH

UntilThen said:


> That is the beauty of Eternity and Odyssey. They only need one good double triode tube. Imagine buying a pair of Mullard ECC32 now. It's more expensive than ginseng !


Yep, nothing to complain about. By the way I read on the Euforia thread that they plan to release a new amp with KT88 as powers. Good that we made our stashes before this, when a mass production amp switches to a tube type, well, prices and availability change, or at least this is what I am expecting.


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## UntilThen

OctavianH said:


> Yep, nothing to complain about. By the way I read on the Euforia thread that they plan to release a new amp with KT88 as powers. Good that we made our stashes before this, when a mass production amp switches to a tube type, well, prices and availability change, or at least this is what I am expecting.



They are not producing a KT88 amp. They are planning on a 300b amp is what I learned.


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## OctavianH

I think this was what I read. I have to admit I would be curious to listen to Euforia with KT88 natively, and also to know if it will support EL34. But in the last months I got used with Eternity and I doubt I'll want another amp.


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## UntilThen (Aug 12, 2021)

OctavianH said:


> I think this was what I read. I have to admit I would be curious to listen to Euforia with KT88 natively, and also to know if it will support EL34. But in the last months I got used with Eternity and I doubt I'll want another amp.



There's the answer to your question. https://www.head-fi.org/threads/feliks-audio-euforia-a-wolf-in-sheeps-clothing.831743/post-16493504

They are not doing a KT88 amp. I've not seen a KT88 being used in a OTL amp and I doubt it's possible or there would be one already. It's always as transformer coupled.

The way KT88 and EL34 is used in an OTL amp like Elise and Euforia is very strange. It won't sound the same as when hearing KT88 / EL34 in a transformer coupled amp.


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## SonicTrance

KT88 is not suitable for OTL amps. It has too high internal resistance. If you parallel two, or preferably three or more, per channel it can be done. There are much better suitable tubes for OTL use than KT88.


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## UntilThen

SonicTrance said:


> KT88 is not suitable for OTL amps. It has too high internal resistance. If you parallel two, or preferably three or more, per channel it can be done. There are much better suitable tubes for OTL use than KT88.



Thanks for confirming Tomas. I don't want to spoil the fun in the Euforia thread, hence I said nothing.


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## OctavianH

SonicTrance said:


> KT88 is not suitable for OTL amps. It has too high internal resistance. If you parallel two, or preferably three or more, per channel it can be done. There are much better suitable tubes for OTL use than KT88.


If they put 2 x KT88 in parallel per channel, I wish luck to those wanting to try GEC KT88 and will search for a quad.


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## OctavianH

I put after 2 months my pair of Verite Open on the head to make some A:B with Ether 2 and after 2 minutes I realized I do not want to wear them. Too heavy and uncomfortable after you get used with some real comfortable headphones. So these go for sale or trade with Empyrean in the same condition. Soundwise are better, at least for my taste, than Ether 2, a little bit different tuned but this just does not matter anymore to me, I want to wear Ether 2 or similar headphones in weight.


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## UntilThen

I set out to recommend you this headphone but I became very interested as a result. Read some of the reviews online.


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## OctavianH

UntilThen said:


> I set out to recommend you this headphone but I became very interested as a result. Read some of the reviews online.


Ah no, Grado! I owned a pair from them, very uncomfortable and the earpads start to dissintegrate fast. I kept it in the box 1 year and they were looking like I used it. It was a cheap model, but all are somehow similar in terms of comfort. Mine was 325is I think, piercing highs, a fast headphone. The cable was not detachable and quite thick and heavy. I sold them many years and and Grado is on my list of "no go". This is their top model I think, well, for me it fails on the design.


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## UntilThen

Have you put it on your head? Those with the big ear cups? I'll briefly audition the GS2000e and it's very comfortable.


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## OctavianH

This one not, but even if it seems to have bigger earpads than the one I had, it has the same headband and the earpads from the same material. I remember it was a kind of sponge, which became firm in time, and when I took them out from the box to sell, after around one year, well, it was looking awful. Nope, Grado is not for me.


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## UntilThen

Even I got used to the weight of LCD4. Now I'm about to try Abyss. Probably the weirdest headphone on planet earth.


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## OctavianH

I think that one is a very good headphone, but it has 640g and it is important to adjust everyting to fit on your head on a specific position. If it moves, sounds differently, at least from what I've read, well not for me. Let's hope you will like it.


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## OctavianH

The last two days were the days of unfulfillment. I've switched through pads, tubes, headphones and nothing convinced me it is the end game.




There are moments when you think nothing is perfect or as you expect. Let's hope the next days will change my mind because at the moment I am willing to sell all my headphones.


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## triod750

You just have to reset your mind. It could be tired. You have put it through a lot of work. Rest your brain for a while. Things are never so good or so bad we sometimes believe they are.


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## OctavianH

triod750 said:


> You just have to reset your mind. It could be tired. You have put it through a lot of work. Rest your brain for a while. Things are never so good or so bad we sometimes believe they are.


Yep, you are, as always, a wise man. I have rolled a lot, struggled a lot to understand new pairs and new headphones. But I reached a point when nothing makes sense. Most probably a break is the wisest thing to do and then reset and take it all again from scratch. I have circled through all pads of Ether 2, all having some pros and cons, but in the end realized that the stock ones provide the most coherent sound. It is somehow the expected conclusion that they released this in the most linear possible configuration and then just released some other pads to fulfil others expectations. The Ether 2 is very different from my other headphones, everything being in front of me. This might be good or bad, they are a more direct and aggressive headphone. Maybe this is why I feel it is not exactly what I expect. But then, other are also missing something. I need a reset.


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## triod750

Sometimes I become overwhelmed by some new tubes or equipment. They seem to fulfil a deep need. After a while I get a subtle feeling that something is missing. Sometimes that feeling disappears and all is well in the world but other instances it just keeps on growing and become unbearable. Time is needed to find out what is happening. Your brain needs time to adapt to changes too. 'Burning in' is often to give the brain time to adapt. When that is done, you often can't remember what was bothering you.


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## SonicTrance

triod750 said:


> Sometimes I become overwhelmed by some new tubes or equipment. They seem to fulfil a deep need. After a while I get a subtle feeling that something is missing. Sometimes that feeling disappears and all is well in the world but other instances it just keeps on growing and become unbearable. Time is needed to find out what is happening. Your brain needs time to adapt to changes too. 'Burning in' is often to give the brain time to adapt. When that is done, you often can't remember what was bothering you.


Well said Mr triod, well said.


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## triod750

SonicTrance said:


> Well said Mr triod, well said.


Tack för det, Tomas.


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## OctavianH

triod750 said:


> Tack för det, Tomas.


Thanks for that. Swedish seems easy to learn.


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## OctavianH

Sleep is good after long listening sessions. It seems easy to listen 16h/day to music but sometimes you need a break.






These Ether 2 somehow remind me about HD600 or HD650, but on steroids, much faster and with better resolution. But somehow these sound similar, in terms of signature. This is not something bad, many still claim HD600 is one of the best headphones around and honestly, I've owned them and loved them. However, they were somehow aggressive to me on long listening sessions.


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## UntilThen

OctavianH said:


> Sleep is good after long listening sessions. It seems easy to listen 16h/day to music but sometimes you need a break.



You do indeed need to take a break. I had to stop and climb a hill yesterday after 2 days with Odyssey.


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## OctavianH (Aug 15, 2021)

UntilThen said:


> You do indeed need to take a break. I had to stop and climb a hill yesterday after 2 days with Odyssey.


I'll do this soon.


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## OctavianH

Enjoying some GEC KT66 with some GEC L63 clear glass this evening. Actually, when I started to think about a new amplifier, this was the pairing I was hoping to be the end game, but in the end I found that this was not a very good combo for my other headphones. With Ether 2 things stand a little bit differently.


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## triod750

OctavianH said:


> With Ether 2 things stand a little bit differently.


You can't stop there! How little and in what way?


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## OctavianH (Aug 18, 2021)

triod750 said:


> You can't stop there! How little and in what way?


My history with the KT66 starts a little bit in the past and in order to explain myself I have to tell the whole story. During 2019 while things on the Elise thread were quiet I was following the Euforia thread to see what people are listening to. During those times it was a marathon of new discoveries, one surpassing the other: EL32, EL38, EL39 and later KT66, KT77, KT88 and in the end GU-50. At that time I was not rolling anything, I was happily enjoying the Tung Sol 5998 with Psvane CV181T2 and my T1.2. All was fine but I had sometimes the feeling that things were a little bit harsh sounding, especially some albums with a "thinner" production. When I first listened to the Gold Lions russian reissues of KT66 I was blown away. Everything sounded much more cleaner, refined, soundstage was wider and the guitar solos were exceptional, alive. GEC KT66 and GE 7581A/KT66 (as drivers, Elise alows it) became my new standard somehow surpassing the old one. I tried KT77 and KT88 and those were no match for me and KT66. When I started to discuss with Tomas about Eternity, my plan was to ask him to build an amplifier for KT66 but since on UltraSonic amplifiers the usage of tubes like 7581A on input is not possible, I had to imagine which could be a good alternative. This is always how our brain works, you always compare what you have or know to what you would like to have, it is hard, at least at my limited experience, to imagine from scratch a completely new amplifier with something I only read about. So I needed a reference to what I was already using. In the end I have decided to use 6J5 / 6SN7 as inputs because this was for me the most flexible solution. Reading a lot on the dedicated 6J5 thread (which is incredible) I realized that a possible dream combo would be the GEC KT66 with the GEC L63 clear glass which everyone was considering warm, rich, decently detailed. So my plan for Eternity was this one, and this is why I have my stock bias settings set for these. During my waiting time for Eternity, I continued to follow several threads and many were complaining about KT66 on Euforia, the bass was bloated and they were totally unimpressed. When I received Eternity, my first listening sessions were with Verite Open and all went smooth. However, I had a feeling that KT66 was not the perfect output because Eternity is much more clean sounding (less distortion) than Elise and it is also more to the neutral side with wide soundstage. But things got worse when I tried T1.2 with KT66. There was a feeling of lack of focus, bass was not clean and I started to remember what people were complaining on Euforia thread. In the end I discovered EL34 which was for me a much better solution for the headphones I owned at that moment in time. Besides the lush and warm sound, with a very good bass extension, which is typical for EL34, I had the chance to discover the Tesla EL34 angled O-O getters which honestly, at around 80 EUR/pair, was for me better than GEC KT66. So I started to explore a lot the EL34 area seeing it not only a good rolling option but more an oportunity which had to be explored fast, until other manufacturers are starting to build amplifiers and make the prices increase. When I bought Ether 2, mostly in my search for a comfortable headphone for summer time, I observed from the beginning that it has a darker nature, and it is somehow differently tuned from Verite or T1.2. With the stock pads, the soundstage is not so wide, it has that kind of "in your face" sound I remember from HD600, but it is more detailed, bass goes deeper and everything is very fast, articulated, tight. My first tries to understand this headphone were with EL34 which paired well, I do not think you can go wrong with EL34 on Eternity and any headphone, honestly. But yesterday I got a different idea, to give KT66 another chance. And voila, KT66 sounds much better with Ether 2. For me this tube is widening the soundstage, reducing somehow harshness from mid frequencies area (this is why on Elise I was always mentioning sweetened mids) and in conjunction with a direct and relatively linear headphone, which has also great bass, can be a very good solution. So, this is why things are a little bit differently with KT66 and Ether. I hope I was able to describe a little bit how Ether 2 sounds compared to my other headphones and also what was my problem with KT66 on Eternity. A good find for me, which puts back on the table a range of tubes I was not able to enjoy until now: KT66/6V6/6L6. I'll have to try these with Ether 2 because they will not sound underpowered or weak as on my other headphones.


----------



## triod750

Thank you for the rich explanation. Back to the old truth; it's all about synergy. There are many ways to do things right - or wrong - and you have to find what works well for you.


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## OctavianH

Yes, it's about synergy and the tube has the same core sound on different amplifiers but it is also influenced by the house sound of the amplifier. Here I have failed to predict. It's like those guys who claim that measurements predict the sound of a headphone, so they look at frequency graphs and think they know all, when in truth, there is much more than that.


----------



## OctavianH

I think @UntilThen will appreciate this logo:





Unfortunately only one of the pair has the logo visible, but what is most important is that both are matched and in very good condition.





Now my EL34 journey comes to an end. Only a pair of RFT EL34 is missing from my collection. All EL34 are exceptional, in my opinion, in Eternity.


----------



## UntilThen

Telefunken holds a special meaning for me. My EL12 spez and one pair of EL11 are branded Telefunken. 2 pair of EL11 are branded Siemens. Unfortunately none of my EL34 are Telefunken. The EL156 coming are Telefunken.  

EL34 are smooth, warm and euphonic. I've Tung Sol 6550 in Odyssey now.


----------



## OctavianH

UntilThen said:


> EL34 are smooth, warm and euphonic. I've Tung Sol 6550 in Odyssey now.


These are more towards neutral and very detailed with sparkling highs, as you said in the past about Telefunken sound. You were right. I think these are the best sounding from all my collection. But of course, it is too early for an opinion, I just gave a hint about some initial impressions. What to say, people of the world send me all your Telefunken EL34 and I'll take care of them for you. Don't be shy.


----------



## UntilThen

They all have their purpose. From the warmer sounding Mullard to the more neutral Telefunken. It's the reason I like the Berlin setup.


----------



## OctavianH

Switching tubes and pads can be fun but it is also a little bit too extreme. You always have a feeling you need to switch something and each variant misses something.





Anyway, I have to say that Ether 2 is definitely not a perfect headphone, but from the engineering point of view, well, it is above many. 
Currently listening to some folk/medieval stuff:


----------



## UntilThen

That's the same cable I use for my Hekse.


----------



## OctavianH

UntilThen said:


> That's the same cable I use for my Hekse.


I have Noir Hybrid for all my headphones. For Audio-Technica I bought the copper one, Noir HPC MK2 because those are brighter. I quite miss my ATH-AWAS, sadly I've returned them but they had something special.


----------



## Magol79

OctavianH said:


> I have Noir Hybrid for all my headphones. For Audio-Technica I bought the copper one, Noir HPC MK2 because those are brighter. I quite miss my ATH-AWAS, sadly I've returned them but they had something special.


Have you tried the ath-adx5000? It's open back and very light. Maybe it's the headphone for you.


----------



## OctavianH

Magol79 said:


> Have you tried the ath-adx5000? It's open back and very light. Maybe it's the headphone for you.


I owned a pair of ATH-ADX5000 and sold it when I bought the Verite Open. It is indeed very light and comfortable (well, some might experience problems with the headband but for me it was fine). It is a kind of HD800 on steroids, more detailed, analytical with wide soundstage, very neutral and natural sounding. For classical or jazz it is perfect, but for me was a little bit bright. It is indeed a very good headphone, well, if you exchange fast the cable which is awful, long, not flexible and microphonic. And the connectors are proprietary (A2DC or something). So even a custom cable was not easy to find.

I guess the perfect headphone for me does not exist. So I'll wait for it to be built by someone.


----------



## OctavianH

Listening to some heavy metal during evening. The new track of UDO sounds like AC/DC LOL.



Some nice combo for this:


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## OctavianH

To Rock or to Bock? That is the question in Tallinn.





I've went to a local store to check some local beers. At first, I was looking at name, price, quantity and trying to read about it, when seeing a beer with ROCK on the name I've just bought some. Marketing done right, if ROCK is the name I buy it without questions asked. I did not care about price or quantity. Same with audio, some builders just make you upgrade. Right or wrong? Well, for rock I'll never ask questions.


----------



## OctavianH

The last episode of my EL34 journey. As every story, it needs an end. I'll let the metal base ones for braver people.


----------



## UntilThen

I'll start talking about my tube rolling journey on Odyssey here. One combination a week. Should finished in a year's time.  

First combination is shown in the picture. Right in the centre in front is the GE branded 5691 made by RCA. It's a 6SL7 equivalent. Flanking it is a pair of Siemens branded EL11 made by Telefunken. These are the alternative drivers to the 6SL7 and they are pentodes but used as strapped triodes here. Right behind the GE 5691 is the Mullard 5u4g made in USA. It's probably a Sylvania or a RCA and it's of the hanging filament type. Flanking the 5u4g rectifer is a pair of La Radiotechnique (RT) EL39 power tubes.

Both EL11 and 5691 are crystal clear and revealing. I almost like them equally but have just a slight preference on the EL11. The RT EL39 are famous for their bass but I find that it is equally glorious in their mids and high frequencies. Very special tubes indeed and could be my favourite of the lot in my chest.

This review is based on using EL11 with EL39 and the 5u4g on duty. Sound is tight and bass is deep and weighted. Nice tempo and fast transients. It's unusual to get crystal clear top end and a lush yet tight tone. Coupled with the best bass on the planet that is tight and controlled, it's an addictive tone. Everything that you long for in a nice tube tone is here but it's never flabby or loose. Mark Knopfler's guitar magic is crazily good on these. These deserved to be heard, especially on Odyssey because it's that good.

For point of reference, I am using Yggdrasil and He1000se and also LCD4 for this listening session and that will be the case in all subsequent tube combination showcase.

I'll give the EL11 and EL39 a score of 9.9 out of 10. Why not 10? Because I'm mean.


----------



## hpamdr

UntilThen said:


> I'll start talking about my tube rolling journey on Odyssey here. One combination a week. Should finished in a year's time.
> 
> First combination is shown in the picture. Right in the centre in front is the GE branded 5691 made by RCA. It's a 6SL7 equivalent. Flanking it is a pair of Siemens branded EL11 made by Telefunken. These are the alternative drivers to the 6SL7 and they are pentodes but used as strapped triodes here. Right behind the GE 5691 is the Mullard 5u4g made in USA. It's probably a Sylvania or a RCA and it's of the hanging filament type. Flanking the 5u4g rectifer is a pair of La Radiotechnique (RT) EL39 power tubes.
> 
> ...


Very nice amp the sockets, the transformers and the design are amazing 
I'm also very pleased with this combination on Eternity. Dis you tried to power your speaker with the same combination ?


----------



## UntilThen

hpamdr said:


> Very nice amp the sockets, the transformers and the design are amazing
> I'm also very pleased with this combination on Eternity. Dis you tried to power your speaker with the same combination ?



Oh Chris, where have you been. Speakers have been given a workout with this combination and it's just as good... The Axis Voicebox is very clear and natural and produce a full on sound that belies it's size. With the floorstander Boston, bass and body tone is more prominent. Would love to try Odyssey with my main floorstanders Axis LS88 back in Sydney in time to come. There's a lot more headroom on Odyssey. It's hardly pushed.

This not the only combination that is good. There are others that are so close but this combination has just the slight edge.


----------



## hpamdr

I've been on long long vacation visiting family.... without amp nor any time to give a look on forums..
Just back with tons of work to plan... 
Currently listening "Daniel Lanois / Heavy Sun" Album with EL39 + NR73 on Eternity (I really missed Eternity and so good sound  )


----------



## OctavianH

While you guys are listening to your beautiful amps I had to put my 2 left hands at work. I always told you how much I appreciate serviceability and comfort on a headphone. Well, today in 10 minutes I've exchanged the headband of T1.2 and the earpads with some spare parts bought online. All I needed was a screwdriver. Nice isn't it? Well, this is what I expect from every headphone manufacturer.





Nothing fancy, nor hard. I mean, if I was able to do this in 10 minutes its clear.





Basic stuff.





Cleaning inside the drivers was also very easy, but I've done it with care, of course. Simple, clean, nice. We have an almost new headphone with a new real leather headband (for original T1.1 but compatible with mine) and new earpads. Why to use service and shipping for this? I love T1.2.





Now try this on other flagships which cost several thousand euros. LOL. T1.2 will never leave my house, the rest of my headphones are for sale. What will come next? I have no idea.


----------



## UntilThen

hpamdr said:


> Currently listening "Daniel Lanois / Heavy Sun" Album with EL39 + NR73 on Eternity (I really missed Eternity and so good sound  )



Thanks for this. Enjoyed 'Power' and 'Way Down'. It's interesting on Odyssey.


----------



## UntilThen

Had T1.1 and T1.2 before. It's in the past now. Wish I could change the pads and leather band of my He1000se so easily.


----------



## OctavianH

Well, I do not claim to put T1 in the same boat with HE1000SE but something happened in the last years: price of a flagship went from 1000 EUR to several thousands and they are harder to mantain or repair but anyway all buy them and discuss more about the color scheme than the sound signature...


----------



## UntilThen

Not sure which flagship you're referring to but Susvara and Abyss owners have generally given intelligent feedback.


----------



## OctavianH

UntilThen said:


> Not sure which flagship you're referring to but Susvara and Abyss owners have generally given intelligent feedback.


Not those, it does not matter.


----------



## UntilThen

Just purchased these Miniwatt EL34 metal base. I ask my supplier (and friend  ) for a newer pair and I was given. According to @leftside, they are 4th generation of EL34 metal base.


----------



## leftside

UntilThen said:


> Just purchased these Miniwatt EL34 metal base. I ask my supplier (and friend  ) for a newer pair and I was given. According to @leftside, they are 4th generation of EL34 metal base.


Yes very nice. 1956 light brown lower base from Eindhoven. Single disc getter at top. Welded plates. Look in good shape. This was the last metal base version made. It went on for one more year to 1957.


----------



## UntilThen

leftside said:


> Yes very nice. 1956 light brown lower base from Eindhoven. Single disc getter at top. Welded plates. Look in good shape. This was the last metal base version made. It went on for one more year to 1957.



Thanks, you're my source of information of these tubes. Perhaps you should start a thread on KT88, EL34, 6550, 6L6GC, EL156 etc. so we have somewhere to share.


----------



## OctavianH

You are lucky to own metal base, but I am not sure if those are exactly my type, I am not looking for the most laid back ones. Anyway, exactly when I said EL34 saga is over I found a pair of Sophia Electric EL34-ST. But these are, for sure, my last ones. I was very curious about them so I couldn't resist since they were not expensive.





They look nice isn't it?  Now I will wait to receive and try them. Blue...


----------



## UntilThen

Leftside have you seen this link? http://www.tube-classics.de/TC/Tubes/Valvo EL34/EL34.htm

I examine my pair. One is SV1 and the other SV0. One is ultra rare and the other very rare.


----------



## leftside

UntilThen said:


> Thanks, you're my source of information of these tubes. Perhaps you should start a thread on KT88, EL34, 6550, 6L6GC, EL156 etc. so we have somewhere to share.


Maybe I should. I managed to complete the KT61/KT63/KT66/KT77/KT88 with boxes collection this week.


----------



## leftside (Sep 2, 2021)

UntilThen said:


> Leftside have you seen this link? http://www.tube-classics.de/TC/Tubes/Valvo EL34/EL34.htm
> 
> I examine my pair. One is SV1 and the other SV0. One is ultra rare and the other very rare.


Yes that is a great source of info. Note what he says about the DD versions.

I think there is a mistake on his site though. I believe “L” to be Brussels (and “X” is Sittard). I’ll double check later.

Your tubes are the 1956-1957 versions. He doesn’t even mention an SY1 for those (“1” is the batch code), so probably ultra ultra rare 🙂 I think you mean “Y” and not “V”.


----------



## UntilThen

leftside said:


> Maybe I should. I managed to complete the KT61/KT63/KT66/KT77/KT88 with boxes collection this week.



Do it.   I know your collection will be superb.  At this stage I'm only buying to use. If it comes with original boxes great. If not I'll still get it if it's in good condition. 



leftside said:


> Yes that is a great source of info. Note what he says about the DD versions.
> 
> I think there is a mistake on his site though. I believe “L” to be Brussels (and “X” is Sittard). I’ll double check later.
> 
> Your tubes are the 1956-1957 versions. He doesn’t even mention an SY1 for those (“1” is the batch code), so probably ultra ultra rare 🙂 I think you mean “Y” and not “V”.



I was paying so much attention to the metal base I didn't read about the DD versions but now I saw. I'm getting them next and after that the expensive KT88.

He did mention 56X/57/X SY0/1 so both mine are SY0 and SY1 in that category. Which means just very rare lol and not ultra rare.  Well at the good price I buy it for, no complains. I did mention V instead of Y by mistake.

I also managed to identify my Miniwatt GZ34 metal base. It's TV1 56H. The 3rd one on that page. Again bought that from another friend for a give away price.


----------



## leftside

UntilThen said:


> I also managed to identify my Miniwatt GZ34 metal base. It's TV1 56H. The 3rd one on that page. Again bought that from another friend for a give away price.


You have the Eindhoven 1956 metal base complete set! I also run the EL34/GZ34 metal base combo most of the time in my preamp. The silver metal bases matches the chrome finish of the chassis


----------



## hpamdr

Next try with Eternity will be 6p7s ( Russian octal 807) adapter is needed and should be done next week..
The tubes i have (Foton 1965) provide 20ma at 200V for a bias around -18V amplification factor is near 7.8. Measure quite well and have 3 matched pairs !

I will give my impression once tested.
@SonicTrance Thomas do you have any clue about good  input tubes for this 6p7s with Eternity ?

// Today i use GU50 + EL11 listening "By Myself" album from Inger Maria Gundersen  on HD650mod. Sound is very dynamic, clear with deep bass and light to wear !


----------



## UntilThen

807s are one of my fav tubes but I have so many favourites now lol. I'm using Tung Sol 6su7gty with Tung Sol 6550 from the 60s. A Tung Sol evening tonight !


----------



## SonicTrance

hpamdr said:


> @SonicTrance Thomas do you have any clue about good input tubes for this 6p7s with Eternity ?


Just use whatever input tubes you like. Remember, the input tubes doesn't drive anything in Eternity so it really doesn't matter. You should get the same "flavor" from say a Ken-Rad 6SN7 regardless of output tube chosen. The 6P7S is a great sounding tube though!


----------



## hpamdr

SonicTrance said:


> Just use whatever input tubes you like. Remember, the input tubes doesn't drive anything in Eternity so it really doesn't matter. You should get the same "flavor" from say a Ken-Rad 6SN7 regardless of output tube chosen. The 6P7S is a great sounding tube though!


From the first try 6p7s is really a good sounding tube same league as KT66 with solid bass and sweet tone, highs are sot as clean as EL39 and not as dry nor punchy as GU50.
Coupling with (russian) 6C5G give a good sound listening Belcea quartet with T1 !


----------



## UntilThen

807 is ok in my books but I'd place quite a few tubes above it.  

A new thread has been started on Pentode tubes discussion. https://www.head-fi.org/threads/the...el51-el39-4654-4699-kt63-kt61-6v6-etc.959519/


----------



## hpamdr

New experiment with border line pentode as input (bias -18V) i got some Visseaux 6U7G in a lot of EL32. This tube used as input with 6p7s give very clean sound even if it is not very powerful.. Nice listening with Madi Diaz "Do it Now"   song (last track of "History of a feeling" Album)
--- With Eternity all sound great ! 
--- Thx Thomas..


----------



## mordy

hpamdr said:


> New experiment with border line pentode as input (bias -18V) i got some Visseaux 6U7G in a lot of EL32. This tube used as input with 6p7s give very clean sound even if it is not very powerful.. Nice listening with Madi Diaz "Do it Now"   song (last track of "History of a feeling" Album)
> --- With Eternity all sound great !
> --- Thx Thomas..


I have tried a bunch of different 6U7G (US and Australian made) in the Glenn OTL with an EL32 adapter. Can be found very inexpensive. 
I have persistent problems with hum to the point that most of them are unlistenable, but overlooking the hum the sound is very nice with great mid bass.
When you look at old radios using this tube you often see a full metal shield around the tube. You can see such shields in the middle of this picture - the shield comes in two halves:



 I don't have such shields, but tried aluminum foil and a Faraday cage but could not eliminate the hum enough to make these nice sounding tubes usable.
Any suggetions?


----------



## hpamdr

mordy said:


> I don't have such shields, but tried aluminum foil and a Faraday cage but could not eliminate the hum enough to make these nice sounding tubes usable.
> Any suggetions?


Hi Mordy, the Visseaux 6U7G I use in Eternity are very silent even with HD650mod. Eternity is very silent with most tubes  more than Elise. 

What I was doing in Euforia was to add a faraday cage made with a small metal soup can with ground wire/contact. But usually this is well working for RFI noise but not with heating hum.  I also added magnet cylinder on the cap wire near the base (the one you can clip are a bit too big but good for a try).

Some tube have hum due to glass vibration propagated from the filament, the only way I found was to add some  ring on the glass. (You can get inexpensive Teflon ring/seal working as good as the one sold for vacuum tube. _I know you like inexpensive stuff to have more to try just like me . I measure tube diameter and remove 10 to 15% to find internal ring diameter and choose 4 or 5 mm thick seal _).


----------



## OctavianH

I took a break of almost 1 month from Eternity. I travelled a lot and forgot about electronics, audio and, most important, work. Now after all this time I came back and just started Eternity with the tubes I left one month ago on it and the Beyerdynamic T1.2 freshly refurbished before I left. It sounds incredible, more towards neutral side than I was remembering. Maybe the new pads? Maybe my brain? Maybe just a long break makes you settle your mind? I will  never know, for sure the new pads are a little bit different in the first hours until they get used with my head, but it is not only that.





Currently listening to the new Portrait album, a true masterpiece.



I missed music. I missed Eternity. But I also attended a fest and saw some very good bands, some of them unknown to me, so it was a time of discovery.


----------



## OctavianH

And the EL34 which does not look like EL34: the Sophia Electric EL34!





Now we need a blue chasis and some blue inputs for it. Looks nice and sounds good, towards neutral like the Telefunkens, with extended highs and very detailed. The EL34 which does not look or sound like EL34, but still sounds good. Damn I love that blue.


----------



## SonicTrance

OctavianH said:


> And the EL34 which does not look like EL34: the Sophia Electric EL34!
> 
> 
> 
> Now we need a blue chasis and some blue inputs for it. Looks nice and sounds good, towards neutral like the Telefunkens, with extended highs and very detailed. The EL34 which does not look or sound like EL34, but still sounds good. Damn I love that blue.


It's nice to hear you still enjoying Eternity!


----------



## OctavianH

SonicTrance said:


> It's nice to hear you still enjoying Eternity!


Of course I am enjoying it. I think Eternity has a great potential.

This evening I investigated a little bit the glow of the Sophia Electric EL34 and I was a little bit disappointed.





The blue glass does not have any effect on the glow, so that's it guys, normal lightning. Now back on Mullards and some well deserved heavy metal.


----------



## UntilThen

The glow comes on at midnight on a full moon.


----------



## OctavianH

UntilThen said:


> The glow comes on at midnight on a full moon.


I live in Transylvania but the werewolves are not fixing my glow. I'll fire them.

In the meantime I have to admit I cheated. No heavy metal tonight, just some cheesy rock music 





Anyway, this album is spectacular.


----------



## UntilThen

Nothing cheesy about classic rock ! 😀

LCD4 into Odyssey and even Jimmy Barnes is in awe.


----------



## OctavianH

I'll tell all one secret: I've always been into G'N'R. These guys were special to me since I was 12. I have no idea why 
And one of the songs I've always had on my top 3 was Coma.



I listen to Coma for tens of years and it remains in present. This song tells so much.


----------



## UntilThen

My fav is November Rain. November is my fav month. 😊


----------



## OctavianH

Mine is December, I was born in it.  November Rain is a very good song and I've listened to it thousands of times but I am aging and I start to loose patience. 10 years ago I was able to listen to it, now I have no patience. It is too slow for me. There is a funny story, when I was a kid I was listening to 30% classical and 70% metal. I was always joking with my friends that when we age, I'll be 70% on classical and 30% on metal. But things got out of control and I am now on 100% metal. Why? Hell knows. I still like classical and if I have a chance I listen to it but I became with age more and more addicted to heavy metal. I still love and know my symphonies but I always prefer fast intense music. Maybe I feel that time is running out. Hell knows, that's what it is.


----------



## triod750

Some years ago I read about a study of musical preferences and IQ. It showed that people with preference for faster 'heavy rock' music in general had a higher IQ. That is not my kind of music - I want silence between notes to build up the yearning for more. To me, the silence is as important as the sound. Some would call me dumb or slow. Some would understand. We are all moving towards death and I am not in a hurry.


----------



## OctavianH

I doubt that the study was right. I also read about higher IQ on heavy metal but this is just a story. I was on this "scene" for more than 30 years and met a lot of people, some smart and some just enjoying a beer. And in the end, what means to be smart? This is also a question. I would say we just enjoy our life and have fun.

But we speak and in the real life stuff is happening and this is Judas Priest playing live in 2021. I make efforts to catch them live this year, we will see.


----------



## UntilThen

Higher IQ with metal ? Hahaha


----------



## triod750 (Sep 10, 2021)

Agree - IQ studies are often way off mark. I just wanted you to feel comfortable and special  .
At least you are special.

Edit. This reply was aimed at you, OctavianH.


----------



## OctavianH (Sep 10, 2021)

Now, well, honestly, UT if you consider higher IQ with classical you are off topic, in my humble opinion. 

Edit: 
I do not want to promote any genre of music. I am fully convinced that all are equal and we just need to enjoy.
I know that I have promoted heavy metal as personal opinion and I will stop doing this. It was just a personal touch on Eternity and what I am doing with it. I will try to stick with objective thread stuff.


----------



## OctavianH (Sep 10, 2021)

I will end the evening with a story. We had debates about IQ or music genres which I consider irellevant. I was born in a musical family. One of my uncles was singing at cello in the local philarmonic orchestra. Now he is dead and I live in his house writing this story. As a kid I went many times to my uncle house. My father was more progressive with music but my uncle was not so. My uncle had brothers singing at several instruments like piano, violin and so on. And they all worshipped classical music. So I've grown with Beethoven, Mozart and many others. I  was never a fan but I started to grow my own list. I liked a lot Tchaikovsky. Maybe he was more accessible to me, I have no idea but when my uncle was playing at cello I was loving it. Later I grew and started to like the Planets of Holst or maybe the 1st of Brahms. I love Brahms, hard to say why but I feel him close. I had a time when I loved baroque music, Albinioni, Vivaldi, Pachelbel or maybe Bach. I never studied or searched for music but I always had a feeling of time. I knew that was before that. And my uncle always helped me. He told me if that was before that and I was mistaking. I was just a kid. But in my heart I always felt need for speed, for intensity and this is why I started to love metal. I always found metal as a faster and more intense part of a chamber orchestra. I have no idea why, I always saw metal as the modern classical offering. Now I am a metal fan, I listen to heavy metal and drink a lot of beer. Besides that I have a career in IT and a beautiful family life. Why I have told this story? Because I felt I have a duty to explain my place here, my heritage and also why I consider heavy metal equal to classical music. You will judge me.


----------



## jonathan c

OctavianH said:


> I will end the evening with a story. We had debates about IQ or music genres which I consider irellevant. I was born in a musical family. One of my uncles was singing at cello in the local philarmonic orchestra. Now he is dead and I live in his house writing this story. As a kid I went many times to my uncle house. My father was more progressive with music but my uncle was not so. My uncle had brothers singing at several instruments like piano, violin and so on. And they all worshipped classical music. So I've grown with Beethoven, Mozart and many others. I  was never a fan but I started to grow my own list. I liked a lot Tchaikovsky. Maybe he was more accessible to me, I have no idea but when my uncle was playing at cello I was loving it. Later I grew and started to like the Planets of Holst or maybe the 1st of Brahms. I love Brahms, hard to say why but I feel him close. I had a time when I loved baroque music, Albinioni, Vivaldi, Pachelbel or maybe Bach. I never studied or searched for music but I always had a feeling of time. I knew that was before that. And my uncle always helped me. He told me if that was before that and I was mistaking. I was just a kid. But in my heart I always felt need for speed, for intensity and this is why I started to love metal. I always found metal as a faster and more intense part of a chamber orchestra. I have no idea why, I always saw metal as the modern classical offering. Now I am a metal fan, I listen to heavy metal and drink a lot of beer. Besides that I have a career in IT and a beautiful family life. Why I have told this story? Because I felt I have a duty to explain my place here, my heritage and also why I consider heavy metal equal to classical music. You will judge me.


Roll over, Beethoven!….🎸🎸🎸…


----------



## leftside

I saw a few metal bands in the early 90's when I lived in London. Back then there was no internet, but we'd see band posters for tours go up. As soon as we saw them being put up, we'd check out the London venue and head straight to the venue to get tickets. I'm not really a metal fan, but I did get tickets for Iron Maiden, WASP and a few underground metal bands. Have to admit I had fun at the concerts. I do like Motorhead and have seen them quite a few times. People who like metal are very passionate about the music, and its great to see that passion. It's not music that people grow out of.

In the early 90's I was more a fan of new wave, goth, alternative and then electronic music and festivals, underground raves and clubs. It was a great time to be in England for all of that. And I haven't grown out of any of that music either


----------



## hpamdr

What is good with Ultrasonic Amp is that everyone can find the tone that match his preferred music style...Even with inexpensive tube (and a bit of luck) you can get great/addictive sound.  

@OctavianH
To be honest, the tube sound is so enjoyable that each time i have to leave far from my amps it is always the same.  When I'm back and can turn on tube amp it is always a joy. Currently it is Eternity and a year ago it was Euforia and same joy to be back to my setup with good headphone !  
What i can tell, is that is not not the same wow effect with SS amps for me !


----------



## OctavianH

leftside said:


> I saw a few metal bands in the early 90's when I lived in London. Back then there was no internet, but we'd see band posters for tours go up. As soon as we saw them being put up, we'd check out the London venue and head straight to the venue to get tickets. I'm not really a metal fan, but I did get tickets for Iron Maiden, WASP and a few underground metal bands. Have to admit I had fun at the concerts. I do like Motorhead and have seen them quite a few times. People who like metal are very passionate about the music, and its great to see that passion. It's not music that people grow out of.
> 
> In the early 90's I was more a fan of new wave, goth, alternative and then electronic music and festivals, underground raves and clubs. It was a great time to be in England for all of that. And I haven't grown out of any of that music either


I didn't knew you left England for Canada. Indeed you had interesting times. We were lucky maybe, now in the Covid times everything changes.


----------



## OctavianH

hpamdr said:


> What i can tell, is that is not not the same wow effect with SS amps for me !


I've just sold my Beyerdynamic A2 and I still have the TT2 integrated amplifier. From time to time I try some of my headphones on that (usually when I get something new). I never felt that Elise or Eternity had a counterpart. From time to time I wonder why I have upgraded from Qutest to TT2 since I use half of the TT2 features. Well, upgraditis. Whenever I recommend something I always say "Qutest".


----------



## OctavianH (Sep 11, 2021)

triod750 said:


> Agree - IQ studies are often way off mark. I just wanted you to feel comfortable and special  .
> At least you are special.
> 
> Edit. This reply was aimed at you, OctavianH.


I am not special at all, just a guy wanting to obtain more from its relaxation hours with music. Luckily my job allows me to listen to music most of the time (well, except meetings which in our "homeworking" times are more and more often and less efficient). And I am not smart enough to make a triple quote LOL.
I sometimes mix personal stuff with music or our hobby just to create a bond between our experiences and the person behind, of course keeping a little bit of anonimity. I have a feeling that in order to understand ourselves we need in first place to know ourselves a little bit. Every opinion here is very personal, based on expectatios and personal taste and then strongly biased by our listening chain. This is why I always say just a few words about a tube combo like "more neutral" or "warmer". I have a feeling that even I say more we are far away from a similar perception. Another reason for letting others say more in terms of audio is that I am not a native english speaker as many here, I can describe to tell a story but when coming tu nuances or tone I feel I cannot express the thing I hear in proper words. It is a limitation which people like me, coming from a latin language, are facing toward the native english speakers from these forums.

Later edit: 
A good example of perception is the Sophia Electric EL34. Reading here I get mixed feelings about them. Many praise their musicality and richness while in my ears these are more on the neutral / tight side of things (of course compared with other EL34). Maybe they compare them with tubes in general and indeed, they are rich and musical, but compared with other EL34 tubes these are a kind of "Psvane CV181T2 vs other 6SN7" and I find them neutral, detailed and very clean, with low distortion and a lot of extension in the treble area (on my Beyers they were a little bit fatiguing on specific tube combos). Now, comparing what I hear with the website, well, a matter of perception.


----------



## triod750

Everybody is special - even you OctavianH. In that way we are all similar, or the same. We might prefer different music but we all love music. No musical form or genre is better than the rest. We can sample it all and choose what we prefer. I grew up with acoustical music, just like you, and that tone speaks to me a lot. Some music is boring to me, no matter what genre, other music is engaging. I can fully understand the similarity between classical music and metal and had I been younger (I have been), metal could have been my choice. I guess there is a period in life that makes us pick our choice.

I feel the same difficulties as you when it comes to expressing nuances in a foreign language. This is extremely annoying.


----------



## OctavianH

Music is a form of art and everyone perceives it differently. As every form of art I associate it with emotion. But I have no idea why for me emotion has to be directly proportional with intensity and speed. It might be adrenalin, like those drivers who feel happy only on the road. Because there are a lot of slow and emotional songs which normally should provide the same feeling. Someone said that if you read 100 books you live 100 lives. I think that this is valid also for our hobby, trying to roll and change and listen to all these types of equipment is helping us enjoy the same song in 100 ways. Rock music cannot match the complexity of an orchestra. But at the level of emotion and intensity might generate similar feelings. I guess emotion and those feelings matter not the source of them.

In the last month I was away of amplifiers, I doubt I will ever need more than Eternity which is very flexible and can provide a good experience also with cheap tubes. As I said in many posts I guess you can be 95% happy with the Tesla EL34 and the GEC L63 clear glass, these being sold around 40 EUR / piece. For me these have a great synergy. But because if you let something go something else takes your sight, I started to read several headphone threads. Of course, I could not miss the Meze Elite one, the headphone being announced around 2 weeks ago. But unfortunately the thread has not convinced me to try it. What convinced me was the Kennerton thread and the Thekk model. So we will have soon a new chapter in Eternity's story, the Thekk on a tube amplifier. Let's see what this will bring us to the table.


----------



## OctavianH

@SonicTrance I found on Oblivion thread a remark that on the other Eternity Low-Z is a 4 Ohm tap and High-Z is a 8 Ohm tap. Is this valid also for me right?


----------



## SonicTrance

OctavianH said:


> @SonicTrance I found on Oblivion thread a remark that on the other Eternity Low-Z is a 4 Ohm tap and High-Z is a 8 Ohm tap. Is this valid also for me right?


It's 4 and 16 ohms actually for both. But, it also depends on what load is on the primary. But around that anyways. As you see by the power output measurements most power is had at 8 ohms. It's not important anyway.


----------



## OctavianH

Enjoying my recently refurbished Beyerdynamic T1.2. I hope the leather headband will last longer than the original one.






Listening to the latest Leprous album, quite a surprise and something different from what I am usually listening (so don't be afraid to try it, you might like it LOL).


----------



## OctavianH

@SonicTrance Am I allowed to use EL156 in Eternity? I see no problem but better to ask.


----------



## SonicTrance

OctavianH said:


> @SonicTrance Am I allowed to use EL156 in Eternity? I see no problem but better to ask.


I see no problems either. That's the beauty of Eternity with tube rolling add-on. You can use pretty much any tubes you like. You just need to find the correct bias voltage.


----------



## OctavianH

I already checked the datasheet and I expect them bias around -15V. No problem, almost the same as EL34.


----------



## hpamdr

OctavianH said:


> I already checked the datasheet and I expect them bias around -15V. No problem, almost the same as EL34.


EL156 need around 2A by tube at 6.3V as the heating transformer is oversized no issues. You will need an adapter not too hard to build or to find. EL12N is easy to find and not expensive and have same pinout as EL156. (_But it is not as elitist_)


My own preferences as today:
Preferred output tubes are EL39 and GU50... But many other are not bad at all.

For input tubes, let say that pentode/tetrode el11, el3N, 6U7G have some swing (euphony) that pair very well with EL34, KT66, 6p7s, EL12sp, EL39 this is a very enjoyable tone !

6C5, 6J5, NR73 pair with everything and with KT88, KT77, GU50 Eternity is precise, fast and detailed and a bit dryer than with previous sets. 

Depending of the mood and the music 🎶 we can fine tune our amp to have different sonic signature (_*Joy of tubes in well designed amp.*_..).


----------



## OctavianH

I enjoyed a lot today the T1.2. Since I've exchanged the headband and earpads I could not let these down. No colour scheme, no special woods, no limited edition, no painted versions. Just a headphone, but I love it and I will never sell it.


----------



## triod750

OctavianH said:


> I enjoyed a lot today the T1.2. Since I've exchanged the headband and earpads I could not let these down. No colour scheme, no special woods, no limited edition, no painted versions. Just a headphone, but I love it and I will never sell it.


Could you please give it away then? I promise not to pay for it!!!


----------



## OctavianH

triod750 said:


> Could you please give it away then? I promise not to pay for it!!!


T1.2 has a place in my heart. I cannot give it away. This is also the reason I repaired it, but since the model is discontinued I doubt it makes sense to invest anymore in it. I said several times that this is my 2nd pair, the reason is that the first pair had a dead driver. The left one. So crap happens also at Beyerdynamic. The good part was that they provided 5 years warranty and I was able to repair them in service free of charge and then gave them to a friend. I bought the 2nd pair because I could not live without them during repairing.


----------



## hpamdr

l have a T1 first gen, it is taking also a special place in my collection. Many would say that it is not the best sounding not the most detailed, not the most dynamic but to me it stay a very good compromise and very musical. You can use it during hours, it is very comfortable and the only goal it reach is to make the music enjoyable !
It was an headphone I got at same time as my first F.A Elise...
@OctavianH what kind of earpad did you got as replacement ? 
I replaced mine with original velour version when I bought the headphone as it was a demo version.


----------



## OctavianH (Sep 16, 2021)

I have ordered standard T1 earpads (velour normal ones) on Amazon. Now I try to look into the account history and I cannot find them. Strange, I'll edit this post when having more information.

Found them, I ordered these. Yesterday I was looking on amazon.de and I ordered from amazon.com. LOL


----------



## triod750

OctavianH said:


> T1.2 has a place in my heart. I cannot give it away.


You could at least try!

You know I was just kidding. They must be good phones for you. You should get another used pair.


----------



## OctavianH

triod750 said:


> They must be good phones for you. You should get another used pair.


They are and what I like is that they are quite indestructible, well, except the moment the driver dies. I cannot say the same for my other headphones.


----------



## OctavianH

So it begins. Interesting times on Discovery channel.


----------



## OctavianH (Sep 17, 2021)

Almost weeked. Some cable rolling. I prefer silver or hybrid cables for these. The full copper ones are for me too much, almost making them sound veiled. Of course, the tube amplifier is also contributing here. But a decent silver cable or the FAW Noir Hybrid are a good match. Original copper cable is, as usual, below expectations.





And then some tube rolling. Tried 6-7 combos but I was not quite pleased until...





...I stopped at 6SL7 + KT66. Brimar 6SL7GT CV1985 + GEC KT66. A very nice and pleasant sound: clean, warm, full bodied. Wiser and more experienced people advised me to avoid high gain tubes for low impedance headphones but in this case I do not hear any distortion or have a feeling that this combo if affecting sound quality. Thekk have 42 Ohms, I set Eternity's impedance switch to low and I am around 10PM with the volume knob. Not bad. In terms of comfort and build quality these are great, no more mousepads to avoid paint falling off as on my other wooden headphones.


----------



## UntilThen

If the Thekk is anything like the Kennerton that I heard from @Yetiman72 , then it's a sound signature that I would like. If that is the case, your choice of 6SL7 and KT66 is spot on because warm and full bodied suit the headphone's more linear and tight presentation. There's also quite a bit of talk on the Rognir model. The Kennertons are beautifully constructed.


----------



## OctavianH

From what I have read on several threads, each Kennerton model has its own signature and you cannot consider one model an upgrade above other. The flagship is the Thror but it has that classic leather headband and it is 100g heavier than Thekk. I was looking for a light headphone with a decently warm signature to be easy to listen for long periods. The Thekk is the warmish open back model, the Thror is more towards neutral and the most famous one is the closed back Rognir which I do not know where to put between these, being a closed back it was not in my focus. Soundwise, there are a lot of very good explanations here about Thekk, I'll try just to say how I perceive these from a personal perspective. 

From the first time I put these on my head I had a feeling that they are very clean sounding, no distortion, almost the same feeling I had when listening for Eternity for the first time coming from Elise. No harshness, echo, sibilance or anything. Somehow soulless but very precise. I knew from the beginning that Eternity has a word to say in this signature. These are clearly not for bass heads, they lack subbass and in some tracks I have a feeling about lack of punch but in rest, these are nice clean and warm sounding headphones with an energetic and dynamic sound. Very easy to listen and get lost in them, also very polite. I made a few corrections to the "stock" signature by choosing a silver cable which added a little bit of life to them.

Now, I judge a headphone based on several things: sound, comfort and handling and in the last year while working from home during the hottest summer of the century I started to appreciate more and more the last 2 aspects. I'll explain. Since the sound is perfectly described in the thread I've mentioned above I'll say a little bit more about comfort and handling. 

Comfortwise these are almost perfect, having around 390g and very nice leather earpads. BUT, they have a problem which I honestly do not quite understand at this price level. The suspension mechanism of the headband is made from a combination of plastic + some elastic material which for me is a minus. I mean they speak about aerospace grade aluminium on their website, leather and wooden finish and they put this kind of cheap stuff on one of the most important parts of the headphone? And even ignoring the materials, this kind of elastic suspended headband puts all the time a pressure on your head and tends to lift up the earpads. Ether 2 is miles above in terms of engineering and comfort of the headband. Anyway, all in all, I consider these easy to wear for long periods of time.





Now, handling. Nobody speaks about this anywhere. Nobody cares about this but I'll explain why for me is important. Handling for me is how easy you remove these from your head with one hand while working or needing to enter in a call. How fast you put these on the desk, how fast you put these back on your head during a busy working day. I also take into consideration how good are these isolating and how tight are these fixed on your head while working with several monitors or moving near your desk. Another aspect is if the earpads are rotating on the headphone or are remaining always in the desired position. Yep, I know, I have some strange needs which are important for me on a headphone and here Thekk gets almost maximum score. Very compact, tight. Durable in the areas which touch the desk, so you just put it without using a mouse pad, cloth or treating it as a piece from a museum. Earpads are fix, always in the good position you put them. You take these off fast, put them everywhere, you take and put these back fast, no adjustments needed.

So, soundwise good, comfortwise good, handling excellent. Now, there is no perfect headphone soundwise, and maybe this is why we use these amps and roll combos on them, to compensate. My job would be in the next day to see how these react on specific tube combinations and decide in the end if these are the headphones I am looking for. We will see.

PS. Ah, another minus is that Kennerton does not accept transfer of warranty. I bought these from classifieds from a very nice felow head-fier, so if the suspension headband has a problem, I'll repair these myself. Another thing I do not understand at this price level.


----------



## hpamdr

Today 12V set !
New experiment with FDD20  (12.6V heat, bias at -2.7 for 4ma et 180V amplification Factor 33,5 ) and GU50... Sound is between 6N7G and NR73 but need more time to burn tube and finalize listening experience with multiple headphone.  At first it is a very clear and neutral sound with some bass extension.

Listening one of my favorite jazz singer Patricia Barber, last album is Clique !


----------



## OctavianH

Damn you wake up early. I've just made the coffee and you are already rolling. And here it is CET+1. LOL

After reading @UntilThen post on Oblivion thread which compares different power tubes I've went back to KT88.





KT88 is a good match for these Thekk which using the Noir Hybrid are already sweet enough and quite warm.


----------



## UntilThen

Kind of strange. We're separated by almost 12 hours difference (it's Sunday 19th Sept 5 pm here) and here I am listening to music with Psvane KT88 Tii. Comparing it to the Genalex KT88. Don't think I will have an answer until a week later but the Psvane are doing very well. Very smooth and clear with a lovely texture. I honestly don't know how many hours are on my KT88 tubes.


----------



## hpamdr

UntilThen said:


> Kind of strange. We're separated by almost 12 hours difference (it's Sunday 19th Sept 5 pm here) and here I am listening to music with Psvane KT88 Tii. Comparing it to the Genalex KT88. Don't think I will have an answer until a week later but the Psvane are doing very well. Very smooth and clear with a lovely texture. I honestly don't know how many hours are on my KT88 tubes.


To what I experienced, KT88 need a burning period > 50h to give it best... This is also the same with GU50 but it also need at least 15 minutes of heating to stabilize and sound really great. New GU50 are a bit dry but after burning period and heating wait sourd is much more neutral and all the spectrum is more articulated without sibilance and still deep and controlled bass.


----------



## UntilThen (Sep 19, 2021)

hpamdr said:


> To what I experienced, KT88 need a burning period > 50h to give it best... This is also the same with GU50 but it also need at least 15 minutes of heating to stabilize and sound really great. New GU50 are a bit dry but after burning period and heating wait sourd is much more neutral and all the spectrum is more articulated without sibilance and still deep and controlled bass.



Both my Psvane KT88 Tii and Genalex KT88 are not brand new. Got the Genalex with the Elekit TU8200 and bought the Psvane from a friend. My guess is that they are low hours because they look newish.

My EL156 is certainly used.


----------



## OctavianH

But I guess you already know that the best sound of the Psvane KT88T2 is obtained with an orange coffee mug near and orange VU meters.





This is a very energetic combo close to solid state. Some do not appreciate these Psvane CV181T2 exactly because it is a little bit sterile towards solid state, but used wisely it is unique, none of my other 6SN7 is able to do this.


----------



## UntilThen

I need to get a Psvane CV181T2 for color coordination.


----------



## OctavianH

By the way, if you look here on the pictures of this Ebay listing you will see EL156 in a voltage converter?


----------



## UntilThen

It was used in LP mastering labs to drive cutting lathes.


----------



## OctavianH (Sep 19, 2021)

After several tries to sell the Verite I renounced. So Verite will remain and Ether 2 and the Thekk will have to go, to fulfil my principle of 2 headphones.
Sad but true, I could not sell these at a decent price to make sense, so I decided to keep them. Love by force, it seems. I'll listen to them during winters and T1.2 during summers. In the end, both headphones are nice.





But one thing I have learned during my planar journey was that there is a certain harshness in all my dynamic headphones. When you have it, you try to get rid of it sweetening all with some tube combinations, when you do not have it you miss it up to a point. The virceral impact of Ether 2 bass was incredible, Verite cannot compete with that. The overall warm and clean sound of the Thekk is also something nice up to a point and cannot be matched by any of my dynamic headphones. And I also appreciated the precision and separation of the planars, but these Verite have some analogue sound which is, indeed, addictive. Not as precise, not as clean, but somehow retro sounding, at least for me.

I'll try to listen more to both Thekk and Verite in the next days, to understand more about each of them in comparison with the other.


----------



## UntilThen

That’s why I’m left with 2 planars.


----------



## hpamdr

OctavianH said:


> After several tries to sell the Verite I renounced. So Verite will remain and Ether 2 and the Thekk will have to go, to fulfil my principle of 2 headphones.
> Sad but true, I could not sell these at a decent price to make sense, so I decided to keep them. Love by force, it seems. I'll listen to them during winters and T1.2 during summers. In the end, both headphones are nice.
> 
> 
> ...


Planar and Dynamic have their own personality and are all addictive in some aspect... 

You should just have one set for winter and one set for summer to just have two headphone under your eyes at each season... 

One Dynamic and one Planar Like T1.2 + Ether 2 for hot season and Verité and Thekk for Winter or mix European when the sun shine  / US when it is cloudy !


----------



## UntilThen

It's Bon Iver afternoon with this setup for me. Will be using EL12 spez for a while because it's the coolest tube and sounds good. LCD5 is supposed to be coming out but I don't chase the latest TOTL headphone.  LCD4 sounds amazing to me.


----------



## OctavianH

hpamdr said:


> One Dynamic and one Planar Like T1.2 + Ether 2 for hot season and Verité and Thekk for Winter or mix European when the sun shine  / US when it is cloudy !


Unfortunately I am not a headphone roller, I usually prefer to have one good enough. Anyway I do not think I missed a comfy model in my trials except Empyrean. But Empyrean on tubes is not quite what I would do, that one is warm and tuned to remove harshness and provide a romantic feeling on a solid state. Or at least this is how I see it. And it is heavily overpriced as well. From the Thekk and Ether 2 I would choose Ether 2. Honestly. But not on a tube amplifier.


----------



## hpamdr

I'm rolling headphone between conf call and music session all the day


----------



## UntilThen

I don't roll no more. I'm free ! From the urge to roll. I listen to music while I work and Roon helps me discover music. It's as good as it gets.


----------



## OctavianH

hpamdr said:


> I'm rolling headphone between conf call and music session all the day


Ah yes, Slack calling, the latest trend in Hi-Fi. 


UntilThen said:


> I don't roll no more. I'm free ! From the urge to roll. I listen to music while I work and Roon helps me discover music. It's as good as it gets.


Let's see how much I'll listen today, yesterday I was able to use Verite 2 hours. We will see today. Damn it's heavy.


----------



## OctavianH

During my planar journey I started to like more and more the 6SL7. Now, on Verite, I realize these remain very good.
That's not good people, I do not want to start again a wild hunt for tubes, mostly because these are already expensive.


----------



## hpamdr

OctavianH said:


> During my planar journey I started to like more and more the 6SL7. Now, on Verite, I realize these remain very good.
> That's not good people, I do not want to start again a wild hunt for tubes, mostly because these are already expensive.


I also have the same feeling, the high mu tubes sound better with planar than with dynamic.

About 6SL7, you can find russian equivalent : Melz 6N9S metal base you should have a dedicated dealer for rusian tubes.
Another test is to use 6N7G in place of 6J5 (if you have the special wiring made by Thomas  )


----------



## OctavianH

hpamdr said:


> I also have the same feeling, the high mu tubes sound better with planar than with dynamic.


Aha! Thanks for confirming this, I was unsure if it is not all in my head.


hpamdr said:


> About 6SL7, you can find russian equivalent : Melz 6N9S metal base you should have a dedicated dealer for rusian tubes.
> Another test is to use 6N7G in place of 6J5 (if you have the special wiring made by Thomas  )


I have the wiring, you deserve a beer for that. And yes, 6N7G with triodes in parallel sounds nice with planar.


----------



## UntilThen

OctavianH said:


> During my planar journey I started to like more and more the 6SL7. Now, on Verite, I realize these remain very good.
> That's not good people, I do not want to start again a wild hunt for tubes, mostly because these are already expensive.



Brimar 6SL7 red letters sound very good on Odyssey. Rivals the EL11. Gain of 70 is nice. I'll PM you a place where you can buy just one. You don't need many. Just one will do. You will be surprised how many types of Brimar NOS tubes there are in that site.


----------



## UntilThen

I don't change my drivers now. I have EL11 and Brimar 6SL7gt red letters there. I switch to use the EL11 or 6SL7 occasionally.


----------



## OctavianH

Almost a week without tube rolling. No change needed. I know so well the Verite Open so I do not need to change anything. I just put a combo and that's it.





It is an addictive and nice tuning, a great headphone if you can pass over some comfort issues which seems to be problematic only for me (no one is complaining abot ZMF headphones and all the other models are similar). Musicwise same situation, I listened all day to the latest Iron Maiden album, not bad, it has some parts which really impress me.


----------



## UntilThen

I would to hear what you're hearing with Eternity compared to my Oblivion and Odyssey. Also @hpamdr Eternity. Just how much is similar and and how much is different.


----------



## OctavianH

UntilThen said:


> I would to hear what you're hearing with Eternity compared to my Oblivion and Odyssey. Also @hpamdr Eternity. Just how much is similar and and how much is different.


I think it is very hard to make a comparison. Oblivion is the most neutral and it is balanced. Odyssey is warm I think, full bodied but clean sounding and keeping the UltraSonic house sound which is top class, a premium amplifier with premium components like the Sowter transformers and so on. Eternity is a tube rolling amplifier for experienced rollers (you need to measure and manually adjust bias, so you need to have an idea about what you are doing). Eternity is on the warm, full bodied side compared to Oblivion and Citadel. But I consider it a chameleon, because with the tube rolling add-on you can change a lot its signature. Wide soundstage and detail remain a part of the house sound, but more than this, hard to say. I would also like to see all 3 on a table and some experienced user to give some impressions but since one Eternity is in Romania, one is in France and there is only one Odyssey in Australia it is not quite simple. Let's hope more and more users will come. Also transport is not easy, these are heavy stuff.


----------



## UntilThen

It’s just wishful thinking from me at 5:30am on a Sat morning.   I solved my 3rd world problem by having Odyssey and Oblivion on the desk. Now I can plug from one amp to the next easily. How I miss the convenience of the rack.


----------



## OctavianH

You are lucky to have 2 complementary amplifiers with the same house sound. You can play a lot with your headphones.
What I was expecting was that you use more Oblivion with LCD-4 and Odyssey with Hekse because I would pair a more neutral amplifier with a more forgiving headphone.
But I have seen that you have also praised Oblivion with Hekse which I consider more neutral, so it seems my assumption is wrong.

Here it is almost 12PM, a good time for one more beer and some more Iron Maiden.

This video is very nice, I love it.


----------



## UntilThen

OctavianH said:


> What I was expecting was that you use more Oblivion with LCD-4 and Odyssey with Hekse because I would pair a more neutral amplifier with a more forgiving headphone.
> But I have seen that you have also praised Oblivion with Hekse which I consider more neutral, so it seems my assumption is wrong.



I was going through a phase... the last few days LCD4 has more head time with both amps. Both amps sound really good with both headphones ! Yet I'm itching for a 3rd headphone sometime early next year. I'll let the dust settles on LCD5 first. Then I'll see if there's a new Abyss model. Susvara is the leading contender at this stage. 

You have your Iron Maiden. How do you like my Shogun?


----------



## UntilThen

OctavianH said:


> 2 complementary amplifiers with the same house sound



You have no idea how accurate that statement is. There's 80% common DNA between Odyssey and Oblivion but the 20% difference is significant.


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## OctavianH (Sep 24, 2021)

I quite like it a lot. That one is a beautiful bottle of whiskey. I do not like whiskey but all my friends like it, so it has to be special.
I have some irish whiskey somewhere in the house but for more than 1 year I had stored it somewhere, so I have no idea where it is. I am a beer guy, I tried whiskey more than 10 years ago.





Nothing beats a good Jever bitter beer on a Friday evening.


----------



## OctavianH

Nice! I found a decently matched pair of Telefunken EL156 on Ebay. I ordered also some adapters. 
Since I broke my principle of no adapters, I do hope these will worth my efforts.


----------



## UntilThen

OctavianH said:


> Nice! I found a decently matched pair of Telefunken EL156 on Ebay. I ordered also some adapters.
> Since I broke my principle of no adapters, I do hope these will worth my efforts.



Nice. If it didn't meet your expectations, just blame Bcowen.


----------



## hpamdr

OctavianH said:


> Nice! I found a decently matched pair of Telefunken EL156 on Ebay. I ordered also some adapters.
> Since I broke my principle of no adapters, I do hope these will worth my efforts.


I hope you will be pleased with the TFK EL-156. 
During last weekend I have made new adapters for EL3N in input/output. 
Some tubes were noisy in Euforia and dead silent with Eternity.
Pairing with 6p7s give good result specially with blues-rock. The high are a bit less present than with El11 but the lower frequencies tighter...


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## OctavianH (Oct 1, 2021)

hpamdr said:


> I hope you will be pleased with the TFK EL-156.


I do not really think you can go wrong with EL156. I have to try this.


hpamdr said:


> During last weekend I have made new adapters for EL3N in input/output.
> Some tubes were noisy in Euforia and dead silent with Eternity.
> Pairing with 6p7s give good result specially with blues-rock. The high are a bit less present than with El11 but the lower frequencies tighter...


So you used EL3N in input socket. Unfortunately my dual adapter broke, we will see if I will obtain others in the future.
I liked what I heard with 2xEL3N in the 6SN7 slot and EL32 in the output.

Later edit 1:
A nice article for the ones who want to read more about EL156.

Later edit 2:
It seems there is another possible manufacturer for EL156 but I have no idea who that one is. They are rebranded National, made in USA. Some pictures here from some website. These do not appear to be chinese, I'll dig also for these.













If anyone knows more about these, please share.


----------



## UntilThen

OctavianH said:


> A nice article for the ones who want to read more about EL156.



Yup I link that article in the main thread when I first got the EL156. Not much is written about it but those who build their own amps were very impressed with it. 

This guy talk a fair bit about it.
http://www.single-ended.com/EL156amp.htm


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## OctavianH (Oct 1, 2021)

Another 2 pictures of the "National" EL156.








I have a feeling these are some russian rebrands because many National tubes I've seen had russian origin, but I have no idea if russian manufacturers ever made this kind of tubes with this socket. And the overall construction, well, reminds me of Telefunken.





We need Columbo.


----------



## UntilThen

They sure look different from the Telefunken EL156. No idea how they sound.


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## OctavianH (Oct 1, 2021)

UntilThen said:


> They sure look different from the Telefunken EL156. No idea how they sound.


We will find out, just bought a quad. I'll pair them in 2 pairs and try one. Then sell one pair. They were cheaper than Telefunkens and Telefunkens were cheaper than the normal price they sell, I was on a hunt this week.

Later edit:
From what I see all chinese EL156 (for example made by Shuguang) have octal socket.


----------



## hpamdr

@OctavianH 
I suspect your tube to be russsian made, the construction is not TFK as top ring getter are missing and for me closer to 6L6GC equivalent.

You should give a look on the bottom of the tube and look  for a typycal russian getter "Flying saucer" square or round like pictured..


----------



## OctavianH

hpamdr said:


> @OctavianH
> I suspect your tube to be russsian made, the construction is not TFK as top ring getter are missing and for me closer to 6L6GC equivalent.


Indeed, when I saw the shape of glass and what's inside I thought immediately about these 6P3S:




However, even if I know that many claim EL156 was manufactured exclusively by Telefunkens, I also doubt russians ever made tubes with Y10A socket.
It is, for sure, a mystery and I will solve it. I bought them just to make a sacrifice on the altar of science, and who knows, maybe I will discovery something.
I will measure them and pair them, and comparing grid bias with other tubes I have I think I will find out something. At least I will not risk anything in Eternity because I will check first what bias to set, then if all goes well I'll put them on the amplifier.

I will also make detailed picture and share them here, so everyone will see the details, and we will hopefully find the answer.
This will, of course, take a few weeks until the tubes and adapters will be delivered. No hurry, EL34 is perfect for me.


----------



## OctavianH

Next episode on Discovery Channel. If you look here on Richardson Electronics website you will find a datasheet of the EL156. The only problem is that the last page with the straight glass shape is added to an older datasheet. However, this mistery tube is called EL156:





I will attach the files for everyone who is interested. So russian, chinese or whatever, I am really curious about these.


----------



## hpamdr (Oct 1, 2021)

The datasheet you share is in German ???
National should only provide English one. I got fake El39 national union just 6p3s with new relabel. About the socket, this is a mistery unless it is manually done.


----------



## OctavianH

It's in German/English but anyway the last page (post above) is added to this:




Ok, fake tube, BUT a fake tube does have a datasheed uploaded on a website? I can accept those are fake but why those have a datasheed on this website.


----------



## OctavianH

The EL156 will definitely be my last investment in output tubes. But I want to try some more inputs, some I never tried like Fivre 6SL7GT and Mullard ECC35.


----------



## UntilThen

I have just spend a week on cheap Mullard, Tesla and Mazda tubes for Oblivion. The improvement is more than subtle and really makes me question why I'm spending lots on NOS tubes. So my decision is to stop buying anymore expensive tubes and prepare my wallet for the Abyss 1266 TC.  

Both Odyssey and Oblivion are sounding pretty amazing now.


----------



## hpamdr

OctavianH said:


> The EL156 will definitely be my last investment in output tubes. But I want to try some more inputs, some I never tried like Fivre 6SL7GT and Mullard ECC35.


I have 12V version Fivre 12SL7GT and i like the sound with heddphone and modded th-500rp but it pair much better with el39 than EL34 or KT66 for me. (I only have rebranded tesla and rft).


----------



## OctavianH

I think Fivre are very nice tubes. I have only a pair of 6N7G and one of 6C5G but both have something in common. And I like to think that the 6SL7GT will be a nice addition to my collection. Also the Mullard ECC35. I think to pair them with KT88 or EL156, but we will see. I hardly wait to receive them.


----------



## OctavianH (Oct 5, 2021)

@hpamdr I think we can try 6G6G on output on Eternity. I've seen some very cheap ones on Ebay. They seem directly compatible, and I expect them to sound close to 6V6. If I drank enough coffee already and read correctly the datasheet bias should be around -11V. Maybe suitable also for input with adapter?


----------



## hpamdr (Oct 5, 2021)

OctavianH said:


> @hpamdr I think we can try 6G6G on output on Eternity. I've seen some very cheap ones on Ebay. They seem directly compatible, and I expect them to sound close to 6V6. If I drank enough coffee already and read correctly the datasheet bias should be around -11V. Maybe suitable also for input with adapter?


@OctavianH* 6G6G are closer to EL32 than 6V6*, you should note that maximum plate voltage is 180V, this is for me a candidate as input tube and on the high limits for output !

Fo using it in input, a minimal adapter is needed to connect g2 [4] to A[3] (100R )// g3[1] to K[8] (not needed if you also keep pin 1) only pin 2,7, 3,5,8 should be connected !


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## OctavianH (Oct 5, 2021)

hpamdr said:


> @OctavianH* 6G6G are closer to EL32 than 6V6*, you should note that maximum plate voltage is 180V, this is for me a candidate as input tube and on the high limits for output !


When I looked on the datasheet I took the max value as fine, but you are right that it is recommended around 180V.





I need to learn more about how to read a datasheet and how to interpret different parameters.
The Datasheet I used is here. What I see there now and I missed is the Plate Current = 11mA


----------



## hpamdr

OctavianH said:


> When I looked on the datasheet I took the max value as fine, but you are right that it is recommended around 180V.
> 
> 
> I need to learn more about how to read a datasheet and how to interpret different parameters.
> The Datasheet I used is here. What I see there now and I missed is the Plate Current = 11mA


I got a Sylvania datasheet from Radiomuseum but it is a bit different. See attachment...

On the datasheet you have it state 11ma at -12V for grid voltage and 180V plate. From the triode graph on the pdf i got from r-type,_(RCA same as you) _you can reach 20ma biasing around -10.5V for 200V. (but you should measure)

*So i apologize and yes you could use it in output at 200V. *
 just measure the bias and pair tubes... What you have to be careful is the max plate dissipation 3.5W so you should unbias around 15-17 ma instead of 20... like for EL32 !


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## OctavianH

hpamdr said:


> *So i apologize and yes you could use it in output at 200V. *
> just measure the bias and pair tubes... What you have to be careful is the max plate dissipation 3.5W so you should unbias around 15-17 ma instead of 20... like for EL32 !


You should not apologize, I have to thank you for helping me and double checking my assumptions. In this way I make sure I do not make something stupid.

Today it has to be an interesting day on the altar of science. I might receive the "mistery" EL156 tubes. I do not have adapters yet, but I will make some pictures, and try to find out more information about the internal construction. I will keep you updated guys, I am really curious.


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## hpamdr (Oct 6, 2021)

OctavianH said:


> Today it has to be an interesting day on the altar of science. I might receive the "mistery" EL156 tubes. I do not have adapters yet, but I will make some pictures, and try to find out more


One of the first check you should do is to verify the heating current just using _f f pins_ on the tube ! (I do not know if you can get heating current from the analyser if not, just heat at 6.3 from the analyzer or anything else and use multimeter in serie. You should get around 1.9A

[----edit---]
for reference on heating current: 
EL32 0.15A
6V6   0.45A
6p3S 6L6 EL3N EL11 0.9A, 
EL12N / EL12spe 1.2A , 
EL39 EL50 1.35
KT88 1.6A, 
KT120 1.8A


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## OctavianH (Oct 6, 2021)

Ok, so the mistery tubes are indeed russian. Regarding the base, if it was manually applied or not, hard to say, I would say it might be. I will attach some detailed photos.

Here we can see that one has "Made in U.S.S.R" while others are marked as USA.





The saucer getter:





And some other details of the internals:











Now, the yellow glue on the base might be a proof of a base manually attached? If yes, what is the original tube designation? I have no idea. I let these pictures here.
I received an invoice, I can return these, I have no idea if I want to do this or not.

Later edit: It might be that those are like these.


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## hpamdr

@OctavianH like i said next step is to measure heating current as you do not need any adapter just plug the 2 F F pin middle of 4 pin serie to get an idea...
I have one mazda 6L6GC and my fake EL39 with similar construction..._ (heating current near 1A)_


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## OctavianH

Yes, I'll do it but not today because I am very tired.

Now, the Fivre 6SL7GT story.





This tube sounds incredible, reminds me of the Fivre 6C5G pair I already have. So the "house sound" of tubes, something I recently learned about, remains a valid point. But this tube, besides the qualities of the other pair, brings back the defects. My pair of 6C5G is microphonic. This means if you put the volume to 0, you hear a glass sound in the headphones. Same if you touch the glass of the tubes. At first I thought it is a specific thing of that pair. Well, the Fivre 6SL7GT has exactly the same behaviour and more than this it is not perfectly silent. I hear some very low hum. Besides this, well, killer sound, warm and clean. I have a feeling less warm than the CV1985 but it is too early to say. I just tried this and wanted to tell you that all my brown base Fivre tubes are microphonic on Eternity. Maybe also a house thing? I will know for sure if I will ever try other type of Fivre. The black base Fivre 6N7G do not have this problem. Maybe I have bad luck, however, not a big deal.


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## OctavianH

In the end I agreed with the seller to return those, so the experiment of measuring the heater current to compare with some known values will not be made anymore. I know, it would have been interesting, but I did not want to risk damaging the tube or making some smoke on the glass or anything since they will be returned. I keep my opinion that those are some 6P3S with a manually exchanged base (is that even possible?).

And, in the end, the video of the day, 6J5 + 5998. Very cool in my book, and a guy with a Motörhead T-Shirt will always get my attention. LOL


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## hpamdr

OctavianH said:


> I keep my opinion that those are some 6P3S with a manually exchanged base (is that even possible?).


I also suspect the same. Manually exchanging the socket is very doable and hypnos1 from Elise...Euforia thread do it to convert Pentode to Triode inside the socket. 
The easiest is to unsoldier from the pin, be carefull when removing old socket. Add some insulated wire you can pull when soldering and use use cyanolite or super-glue or .. to cement the new socket !


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## OctavianH

Yep. In the meantime, the real deal:





Damn, these are big, just look at the poor EL34 sitting like a small child near them.


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## OctavianH

What can you do when your EL156 adapters are still on the road? Well, beer rolling. Never needs an adapter and it is always the good combo.





But I've done also an 1:1 of the Verite vs Thekk and remembered what I like on dynamic vs planar headphones. However, Verite wins for me.


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## jonathan c

OctavianH said:


> What can you do when your EL156 adapters are still on the road? Well, beer rolling. Never needs an adapter…


Does your midsection need an abdapter?…


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## OctavianH

jonathan c said:


> Does your midsection need an abdapter?…


Thankfully not. No adapter and no top cap regardless the section.


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## OctavianH (Oct 11, 2021)

It seems I wil miss Wacken Open Air in 2022, it is already sold out and I could not get a ticket. I waited in line in vain. But I will attend Summer Breeze 2022 with Blind Guardian headliner. Fair enough, these times were hard for all of us. I watch now the anniversary show for Imaginations From The Other Side and I do hope they'll remain in the same form for the next summer.


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## hpamdr

Made a new adapter this week-end to be able to use 6M6G in input (This will also target 6G6G, 6V6 ...).
6M6G tube is close to EL3N, the pair I have is made by Visseaux and bias at -7.8V at 180V for 4mA Mu is around 20 like 6J5, 6SN7...

Currently listening it paired with 6p7s in output  and T1 a nice album for sad day !


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## OctavianH

I was planning to use 6M6G in output instead of EL3N but since the prices are quite high and I have 6 pieces of EL3N, well I will stick to these. 
Let's hope soundwise are the same. I'll obtain soon some adapters, no hurry, today is ECC35 day.


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## hpamdr

OctavianH said:


> I was planning to use 6M6G in output instead of EL3N but since the prices are quite high and I have 6 pieces of EL3N, well I will stick to these.
> Let's hope soundwise are the same. I'll obtain soon some adapters, no hurry, today is ECC35 day.


Mullard ECC35 are not in the democratic side of the wallet but I hope that you will have good matched tube. This is  
I got the 6M6G for 20€ a quad (long time ago in garage sell) good old time !


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## OctavianH (Oct 11, 2021)

hpamdr said:


> Mullard ECC35 are not in the democratic side of the wallet but I hope that you will have good matched tube. This is
> I got the 6M6G for 20€ a quad (long time ago in garage sell) good old time !


You were lucky.

Now, regarding the ECC35, mine is rebranded as Zaerix and was not so expensive, but it is not perfectly matched either. Let's say "it works".
With Bias around -1.3V I get 2.6mA / 3.3mA. Not good, not bad either.




Soundwise, well, warm and polite, but I will need more time with it. From Fivre 6SL7GT / Mullard ECC35 and Brimar CV1985 I prefer the last one. At least now and with Tesla EL34.





I start to think that there are similarities of the Mullard ECC35 with the Mullard EL34 xf2. Same for the Fivre 6SL7GT and the Fivre 6C5G. I guess that's the house sound, different types but something in common, somehow. A good addition to my collection, but now I stop. Next step: adapters for EL156 and that's it. I take my popcorn and let others continue the crusade.

A picture with all 3, from left to right: Mullard ECC35 (rebranded Zaerix), Brimar CV1985 and Fivre 6SL7GT.


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## OctavianH (Oct 13, 2021)

@hpamdr You said some day ago that you tried EL3N. Have you tried by chance an "all" EL3N setup (with adapters to 6V6/6J5)? I plan to do that since I have 6 pieces.

Some nice read about EL3N.


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## hpamdr

OctavianH said:


> @hpamdr You said some day ago that you tried EL3N. Have you tried by chance an "all" EL3N setup (with adapters to 6V6/6J5)? I plan to do that since I have 6 pieces.
> 
> Some nice read about EL3N.


In fact i did a pair of adapter EL3N -> 6J5 (_I dislike dual adapter_). including 100 Ohm resitor. this adapter is also usable in output side. 
This is not to hard to build (this is the recipe)
- you mark with a pen FF AGK  from EL3N socket to 6J5 base
- using a mini grinder to male hole from top to midle of  in front of marks.
- use colored/numbered wire you solder to 6J5 base pins and out to the right holes
- add a small spacer or grid more space in 6j5 base to insert/remove tubes from socket.
- solder wire, add resistor  and insulate all with thermo tube or good electrical rubberband...


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## OctavianH

You are several levels above me in this area. I know the theory but I have 2 left hands and I am quite busy in this period, so I went on the easy path and asked Deyan to build me a few adapters. So in the next season on Eternity we will see:
- 2 x EL156 in the output section
- 4 x EL3N
- 2 x C3g in the input sockets
Stay tuned.


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## OctavianH (Oct 17, 2021)

Eternity received a well deserved dust clean-up. On Wednesday, 20.10 it will have 6 months (since I've receive it). Thinking on the past 6 months I am quite surprised that nobody went on the same path and there are only 2 amplifiers of this type. No problem, mine is here to stay.





In the meantime, as a preparation for some input rolling, I double checked maximum negative voltages I am allowed to set on input/output.


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## OctavianH

Evening. The artist in me wanted to make a picture. Fivre 6N7G + Mullard EL34 xf2.


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## OctavianH

Fun continues on Discovery Channel. Mullard ECC35 with Mullard EL32.





These EL32 are widening the soundstage, compared to EL34, bass not as tight, but with ECC35 these are a decent combo. I wanted to listen more to ECC35 but Mullard EL34 xf2 was a liitle bit too much for it. So I had to switch to EL32 to obtain a good synergy. A warm relaxing tone, very pleasing to my ear, almost liquid as I remember GEC KT77 were. Interesting find. With Eternity possibilities are infinite.


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## hpamdr

OctavianH said:


> Fun continues on Discovery Channel. Mullard ECC35 with Mullard EL32.
> 
> 
> 
> These EL32 are widening the soundstage, compared to EL34, bass not as tight, but with ECC35 these are a decent combo. I wanted to listen more to ECC35 but Mullard EL34 xf2 was a liitle bit too much for it. So I had to switch to EL32 to obtain a good synergy. A warm relaxing tone, very pleasing to my ear, almost liquid as I remember GEC KT77 were. Interesting find. With Eternity possibilities are infinite.


EL32 is what i call romantic tube, it add emphasis and give you sweet tone with sensation of very large scene.. 
This is the kind of tube i like with easy listening, small chamber ensemble and calm session the drawback it the pairing with hungry headphone where you can miss a bit of juice.. 

// Combo of today 6M6 an EL12spe and hedd


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## OctavianH

Another very good combination for Mullard ECC35 is the Sylvania 6CA7. All these tubes are "fat bottle".





These 6CA7 have the bass of KT88 and the mids of KT66, and somehow wider soundstage than EL34. Not as romantic as EL32, good bass and incredible mids. Excellent for electric guitar. This combo is one of the best I've heard on Eternity, at least for the genres I am listening to.


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## OctavianH

For the ones intersted in EL156, careful what you buy. I saw by mistake today this Ebay listing, EZ150 which from the pictures looked close to EL156. However, according to Radiomuseum these are full wave rectifiers. So EZ150 is different from EL156. Now I'll look twice on any listing to be sure. LOL


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## triod750

OctavianH said:


> For the ones intersted in EL156, careful what you buy. I saw by mistake today this Ebay listing, EZ150 which from the pictures looked close to EL156. However, according to Radiomuseum these are full wave rectifiers. So EZ150 is different from EL156. Now I'll look twice on any listing to be sure. LOL


If you stay away from eBay you will make less mistakes. Simple!


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## OctavianH (Oct 22, 2021)

triod750 said:


> If you stay away from eBay you will make less mistakes. Simple!


I fully agree with you! I wanted to warn people about tubes with deleted prints, where similar form and base might be misleading.


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## triod750

OctavianH said:


> I fully agree with you! I wanted to warn people about tubes with deleted prints, where similar form and base might be misleading.


And I was only joking at your expense. I am a bad person, beware!


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## OctavianH

triod750 said:


> And I was only joking at your expense. I am a bad person, beware!


I do not believe you. Well, mine seem legit.


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## OctavianH

I was looking today at my Mullard (Valvo) EL34 xf2. I have 7 pieces with different date codes (2 x B2J5, 2 x B3J2, B5K1, 2 x B7B1). Even if internally these a looking identical, I've observed some differences in the base. For example B7B1 misses pin 6 compared to B2J5.







No big deal, but I did not knew that and I have them for some time already. Who knows what I'll discover next time I look at them.


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## hpamdr

Pin 6 is not used so it does not harm  
No small profit !
// in 6L6 GC even pin 1 is missing


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## OctavianH

hpamdr said:


> Pin 6 is not used so it does not harm
> No small profit !
> // in 6L6 GC even pin 1 is missing


Yes, only those B7B1 have the pin missing, they made some cost reduction in 1967. According to this very nice link are these:


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## OctavianH

No change for almost one week. Or more? I cannot remember and in the end it just does not matter. The pairing of Verite with Sylvania 6CA7 and Mullard ECC35 in Eternity is for me almost perfection. I do not call it perfect only because I do not believe in such a thing. No need to roll, just listen.


----------



## OctavianH

When my beer pint discusses with my headphones it means it is Friday Beerday.





I have to admit I am quite bored, my EL156 adapters are blocked in customs and nobody understands what is happening there, a kind of Area 51. Let's hope I will have soon new stuff to contribute. For example EL156 or EL3N or C3g. I hardly wait.


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## OctavianH

After 2 weeks I need a change. Even if I like a lot a specific combination, after some time I feel I need to try something new or to revert to an older combo. I love this flexibility, because each of these have something to say. There is no right or wrong here, flexibility means you can watch the same scene from different angles. This is why I will never buy an amplifier without adjusting capabilities or what we call here tube rolling.


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## hpamdr

Listening a lot of blues with 6M6G and GU50 HD800S. 
I also got a new toy rpi4 with pi2AES using piCore player and sounccheck special tweaks for squezelite-custom...
Eternity is still fascinating me for it's ability to render music with huge dynamics and natural.


----------



## OctavianH

hpamdr said:


> Listening a lot of blues with 6M6G and GU50 HD800S.


There are some good discounts here for HD 800S. How do you see it on Eternity? Bass is enough? Speed? Detail? Does it make sense to add it to my collection, now that I sold all my other headphones except T1 and Verite. I still search for a comfy headphone to replace Verite but still retain some of its sonic qualities.


----------



## hpamdr

OctavianH said:


> There are some good discounts here for HD 800S. How do you see it on Eternity? Bass is enough? Speed? Detail? Does it make sense to add it to my collection, now that I sold all my other headphones except T1 and Verite. I still search for a comfy headphone to replace Verite but still retain some of its sonic qualities.


I personally like HD800S even if some argue that Bass are not "right", it is a good complement to T1 and you can find it for fair price. 
It is more detailed and is more on the hight side and more dynamic than T1. I like it a lot with vocals (but not as much as heedphone). It is light and very comfortable and you can have support in Europe direct from Germany ! 

Eternity drive it wondefully on low gain at 25-50% of volume. It pairs well with dynamic tubes like GU50, EL39  in my setup, with KT88 you should add some darkness if you miss deep BASS.  I'm not able to compare with Verité as the only audition i did was not in good condition.


----------



## OctavianH

hpamdr said:


> I personally like HD800S even if some argue that Bass are not "right", it is a good complement to T1 and you can find it for fair price.
> It is more detailed and is more on the hight side and more dynamic than T1. I like it a lot with vocals (but not as much as heedphone). It is light and very comfortable and you can have support in Europe direct from Germany !


Yes, this is what I like at these old german companies, support. My T1.2 looks incredible with the new headband and earpads, and works as a charm. Even for HD 800S you can find easily parts if needed. Now, try this with other more expensive boutique headphones... But I always considered HD 800 tuned somehow for classical music and with my genre preferences I always considered it too bright. I never heard the HD 800S, but I guess it is close to HD 800. I will think about this.


----------



## whirlwind

OctavianH said:


> After 2 weeks I need a change. Even if I like a lot a specific combination, after some time I feel I need to try something new or to revert to an older combo. I love this flexibility, because each of these have something to say. There is no right or wrong here, flexibility means you can watch the same scene from different angles. This is why I will never buy an amplifier without adjusting capabilities or what we call here tube rolling.


Same here...I don't roll much anymore, but every couple of weeks I will throw a different combo in just for a different flavor. 
Great pic and great looking amp


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## hpamdr

The *S* is not as bright than the original HD 800 but brighter than T1. It takes a little time to get used to it anyway, once trained you feel it more natural and feel wider sondstage than T1  ! _(I do not listen Metal nor Electro and i'm a bit older than you  )_


----------



## OctavianH

hpamdr said:


> The *S* is not as bright than the original HD 800 but brighter than T1. It takes a little time to get used to it anyway, once trained you feel it more natural and feel wider sondstage than T1  ! _(I do not listen Metal nor Electro and i'm a bit older than you  )_


Well, that very large soundstage is worrying me a little bit. I do not know why but I associate the soundstage of a headphone also with the genre one is listening. For example, a large orchestra in a large hall needs audio equipment with wide soundstage to sound its best. A rock band performing in a limited size stage might not sound so good on a very wide soundstage because the overall impression looses intimacy. This is why I always considered the HD 800 tuned for classical and large venues, while T1 being more romantic somehow to pubs, bars or smaller concert venues where a 4-5 piece band plays. Of course, I might be wrong. Another thing which makes me skeptical about HD 800 is the brightness, I am fully convinced it is detailed and analytical, but I am unsure about its presentation for example for electric guitar. I have a feeling these kind of instruments need a little bit of warmness to shine: electric guitar, piano, vocals. However, I have learned to play a little bit with soundstange and level of warmness on Eternity by choosing specific combos. I will think, you gave me a serious subject!


----------



## OctavianH

New stuff to try: Ken-Rad 6J5GT/G. Nice sounding ones.


----------



## OctavianH

Black Sabbath has no age. I love it. Bill Ward has to be there. This is the quintessence of music for me.


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## OctavianH

And after that I went to Empire...


----------



## OctavianH

Yesterday I went on the nostalgia path. It is fine, there are bands you followed your entire life and they are, indeed, the best. But I always search, as in tube rolling, for new experiences. There are so many good new bands which sound killer, thanks to new production levels, and are in a way, the same as these big bands were sounding in their earlier career. I love Black Sabbath, I love Queensrÿche and the same for all the good old bands like Motörhead or Judas Priest. A big part of my life went for them and also for the bands in the more "extreme" area like Obituary, Morbid Angel or Death. I also listen to extreme metal. But this morning I decided to go back to new territory and one of the bands I love and recommend is Striker. These guys are killer.



I like a lot the new wave of heavy metal which for the last 5 years brought us a lot of incredible bands. Heavy metal is coming back, from the 80s and we are here, to follow. Striker, Enforcer or Wolf are a good example of post 2000 bands which still have a lot to say on this genre. But I will stop here, this thread is about tubes not rock music.


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## OctavianH

Now more on topic but not quite. The reason I chose Tomas to build me a tube amplifier was that I've seen that he has vision. He designs tube amplifiers which are compensated (if this is the right word) by newer technology and work properly because of the new tricks. These tricks are well known for the experienced listeners of tube amps (not me) and many use CCS, MOSFETs and stuff like these. The output is a more cleaner, precise sound, more details but still, not solid state dry sound we all, the tube lovers, hate. A kind of more detailed sound, cleaner and with less distortion but with the beloved harmonics. But this is what Tomas explains much better than me on his website.

The reason I make a new post here is that I want to say again how important is the source on what we listen. We always pay a lot on tubes, on amplifiers or headphones but sometime we forget about power cleaners, filters or source optimization. I will tell you my story, which will be hopefully helpful for someone even if it is somehow off topic. I listen to music from my PC because Foobar is the most comfortable way for me to listen to hundreds of albums. I have a wall of CDs but who has time or wants to search for something? (remember, here we have a heavy metal fan). I listen for CDs from time to time but I work on my PC 12-16 hours a day, when needed, and I need my music to be close to me and I want fast searching on my collection. But as we all know, PC brings problems, USB transmission and jitter and other stuff. I have tried to improve this for the last 3-4 years trying many tricks like iFi products or Uptone USB Regen, but for me the best was the JCAT USB Femto. It is expensive, around 400 EUR, but it makes miracles. It is a PCI express USB board and you just plug it in your PC PCI Express 2.0 or newer port and power it externally via an Sbooster linear power supply or other 5V power source and thats it. Your DAC will evolve a lot, like my previously used Qutest or currently TT2. BUT JCAT released last year a new model called JCAT USB XE. It is, as expected, more expensive, but it brings a lot of improvement soundwise. Well, my post does not want to make any marketing to JCAT products, but want to express more about how important is our source, about how and what we feed to our DAC and then how much better a custom made amplifier can sound when using these simple tricks of feeding the DAC good data. I use here TT2 and MScaler. The Mscaler is known for its merits, all can read a full thread of it. But when I upgraded my JCAT USB card from the normal Femto to XE I went up to a definitely new level. It is incredible to find out that using TT2 and Eternity and Verite you can still find an improvement. Well, source matters, never forget about this guys!

Sorry for off topic, sorry for heavy metal links, somehow a thread is alive when people are alive and it is hard for me to split audio and music from the things I love. But I try to be objective, to speak about what is in the benefit of others and to bring new information, if it is possible, to help others decide better when they spend some money. We all love music otherwise we will not be here, let's hope I am helping someone sometime to make a better choice for his/hers audio system.

Now, I go back to my Striker listening session. Respect Canada for bringing us such a great band!


----------



## OctavianH

Today it was a day for music, how lucky I am. And I have listened all day to Eternity, and one of the bands that stood out was Unto Others with their lates offering Strength. But one song made me think a lot, more exactly Hell is for Children. It is a cover version of Pat Benatar.



Listen to it guys, it is not rock or heavy metal. But it says a lot about life, values and more. Never forget to protect the ones you love, never forget to report any child abuse or look on the other side when something is not right. We have amps, we have tubes and we are lucky, but this crap is happening near us and we need to take action.


----------



## UntilThen

OctavianH said:


> I do not believe you. Well, mine seem legit.



Well did you try the EL156 in Eternity?


----------



## UntilThen

OctavianH said:


> After 2 weeks I need a change.



I have stabilised. I hardly change tubes now. I'm mainly using EL11 with EL12 spez. This is the best combination for me. I can go weeks with this combination.  I've also gotten the HD800S. Love both the HD800 and HD800S with Odyssey.

Took a picture of Odyssey on the 13th Nov 2021 because it's Odyssey 3 month anniversary. That McDonald coke is to remind me of the event.


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## OctavianH (Nov 14, 2021)

UntilThen said:


> Well did you try the EL156 in Eternity?


Not yet, I still wait for my adapters. But I will try it soon.

I thought a lot to get the HD800S at the offer they have now, it is a good price, but I decided to remain on Verite, I think HD800S will be too bright for me. I had in the past a headphone I liked more than HD800, the ATH-ADX5000 from Audio Technica and sold it for the same reason. Even with the most "romantic" tubes I was not getting what I expected. It is true that I never heard HD800S, but I think I have an idea about how it sounds.


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## OctavianH (Nov 15, 2021)

Hmm, Monday morning and things are happening on head-fi! The new Feliks Audio 300B amp is here, nice piece of furniture with wood and everyting people like, and we have also a new headphone from Meze? A kind of Empyrean for the poor, made of plastic (I guess actualy it is magnesium)?





Well, at 2000 USD which will translate to 2000 EUR in Europe, I start to regret not trying the HD800S at almost half the price. I foresee how this thread will end: in 5 years we will not listen to anything because we will not afford any headphone and Eternity has no outputs for speakers. LOL

Later edit: Ah! They changed the mini-XLR connectors, so we need another cable for this.


----------



## hpamdr (Nov 15, 2021)

OctavianH said:


> ..........I work on my PC 12-16 hours a day, when needed, and I need my music to be close to me and I want fast searching on my collection. But as we all know, PC brings problems, USB transmission and jitter and other stuff. I have tried to improve this for the last 3-4 years trying many tricks like iFi products or Uptone USB Regen, but for me the best was the JCAT USB Femto. It is expensive, around 400 EUR, but it makes miracles. It is a PCI express USB board and you just plug it in your PC PCI Express 2.0 or newer port and power it externally via an Sbooster linear power supply or other 5V power source and thats it. Your DAC will evolve a lot, like my previously used Qutest or currently TT2. BUT JCAT released last year a new model called JCAT USB XE. It is, as expected, more expensive, but it brings a lot of improvement soundwise. Well, my post does not want to make any marketing to JCAT products, but want to express more about how important is our source, about how and what we feed to our DAC and then how much better a custom made amplifier can sound when using these simple tricks of feeding the DAC good data. I use here TT2 and MScaler. The Mscaler is known for its merits, all can read a full thread of it. But when I upgraded my JCAT USB card from the normal Femto to XE I went up to a definitely new level. It is incredible to find out that using TT2 and Eternity and Verite you can still find an improvement. Well, source matters, never forget about this guys!
> .........


Yes files, source and DAC matters when you have good amplifier and headphone !
All the game is to assemble a good match from DAC, Amplifier (tubes), Headphone. Chasing perfection could be a a non ending game with extensible wallet.
It turns for me  that Eternity is a really good amplifier and depending of tubes you can get many flavor and sound signature which make headphone and DAC pairing much more flexible.

I'm also using my PC for work a lot unfortunately even if I have spent a lot on usb cleaner and better power supply and jitter optimization at the end I have switched to a much lighter players.  About jitter and usb isolation for me it turned to be more an issue due to not have a dedicated player unit and a not so well implemented usb (isolation/clock) on DAC. So i decided to not invest anymore on my work PC for music listening. I have  professional NASs where work and music data are stored which makes my life easier !

I use Rpi4 PiCore player with  Pi2AES hat or daphile on a dedicated nuke PC/laptop. I have a huge collection of music file (No Roon, No Spotyfy, No Tidal...) and stream from bandcamp from time to time.  Streaming from LMS from NAS with Web based UI and is easy to use from my work laptop and allows to control multiple players in home.
I've also many DACs some that measure well and some I finally likes better ! The Soekris ones sounds incredible for the bucks and matches my needs ! 

With most DAC in a Chip  (mostly the one that measure well) I use oversampling with SRC filters and with Soekris i use no oversampling and let the DAC do it's job with some customized filters.   

All this is only audible if at the end you have a good amplifier with a good headphone !

Currently I'm so happy with Eternity, Soekris 2441 and rpi4 (with SoundCheck kit) + pi2AES that I even just switch some tube combination depending of my mood and music.
I sill have other DAC/player/amps in other rooms but i do not personally listen as much as the previous one !
So finally many thanks to Thomas, Soren, Michael, Klaus  to makes me pause in purchasing new stuff ... Now it time to just enjoy listening music !


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## OctavianH

hpamdr said:


> I'm also using my PC for work a lot unfortunately even if I have spent a lot on usb cleaner and better power supply and jitter optimization at the end I have switched to a much lighter players.  About jitter and usb isolation for me it turned to be more an issue due to not have a dedicated player unit and a not so well implemented usb (isolation/clock) on DAC. So i decided to not invest anymore on my work PC for music listening. I have  professional NASs where work and music data are stored which makes my life easier !


I was quite surprised about the Jcat USB XE vs the previous model Femto. If I would try to describe what I hear, well, it is not about details but more about coherence of sound, if this makes any sense. But there is a big difference if you power such an USB card internally from the PC's ATX power supply (usually a MOLEX connector) or if you power it externally via a linear power supply. And now we came about the elephant in the room: it does not quite make sense to buy only the USB card, you have to buy at least an Sbooster 5V for it. Difference is quite big, audible. I have thought a lot to go for a dedicated music server, or a small Macbook on battery, but in the end I decided to continue to use a PC for the times while I work or play something while listening to music. That's it, you cannot try all of them, you need to find your best scenario.


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## OctavianH

Finally some action: Mullard ECC31 in the 6J5 slots of Eternity, with triodes in parallel. Bias around -4.4V @180V/4mA.






So now I can try something I wanted for a long time: Mullard ECC31 + Mullard EL34 xf2. This one is a good one, it will keep me busy for a while.





Thinking a little bit on the last 6 months with Eternity, I have to say that I derived a lot from the path I was expecting to follow. I wanted to move from 6SN7/6AS7 to KT66 and 6J5 natively on the amplifier, with manual bias to be sure all works as I expect and here I am: EL34 and ECC35/ECC31 and CV1985. In the meantime I made some cost saving selling a lot of the old tubes (even 2 pairs of 5998 which I never thought I'll do). So my collection is smaller but the sound and satisfaction is greater. I do not regret at all, these types I've mentioned are for me much better than the older types and, at least EL34 and 6J5, are also much cheaper. Now I guess the next logical step would be ECC32 on inputs and EL156 on outputs. We will see. I have a feeling that ECC31/35 and the CV1985 will replace more and more in my listening sessions my 6J5 which, at a point in time. will leave my collection. Which is my favourite? Well, CV1985 but it is hard to make a top, all being spectacular on Eternity. And this is why I have to try ECC32.

Good times ahead. The new Dream Theater album sounds "colossal", if I can say this, on this 4 x Mullard combo.

PS. I could not find graphs for ECC31 but DuoVac saved me. It was one of the best acquisitions I've made helping me many times to pair tubes or to check the situation before doing something stupid on the amplifier. It's my guardian angel and because of it I never burned an output fuse. So it deserves all my consideration.


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## hpamdr (Nov 17, 2021)

OctavianH said:


> Finally some action: Mullard ECC31 in the 6J5 slots of Eternity, with triodes in parallel. Bias around -4.4V @180V/4mA.
> 
> 
> So now I can try something I wanted for a long time: Mullard ECC31 + Mullard EL34 xf2. This one is a good one, it will keep me busy for a while.
> ...


ECC31 and the Navy version NR73 is one of my favorite driver/input tube paired with GEC 6080 on Euphoria or EL39 on Ethernity. ECC32 are very close to ECC31 but much more expensive (5 times).. You can use only one on Ethernity in 6SN7 socket, with adapter it could be the same with ECC31.

Using dual triode tube in input socket is less precise but change amplification factor and it add some hysteresis wich could be very pleasant and musical, it also allows to use unballanced T1/T2 tube.

About DuoVAC, I totally agree having an easy to use  measurement tools is a very good complement for precise manual bias amplifier. It makes you much more confident and prevent to plug exhausted or totally unmatched pairs. Even taking into acount deltas due heating voltage and gyrator you can guess good bias value and know for sure that every tube is unique  !

Curently listening : (Wilco : Ode to joy [2019])



And give a look on track (4) .....


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## OctavianH

hpamdr said:


> ECC31 and the Navy version NR73 is one of my favorite driver/input tube paired with GEC 6080 on Euphoria or EL39 on Ethernity. ECC32 are very close to ECC31 but much more expensive (5 times).. You can use only one on Ethernity in 6SN7 socket, with adapter it could be the same with ECC31.


ECC2 prices are crazy, so this will remain only a plan at the moment. I never tried ECC31 on Elise, I guess at Ih=0.95A I was a little bit above 6.5A with 6080 (2x2.5 + 2x0.95=6.9A). But this has to work fine on Euforia. I never liked 6080 (at least the Mullard I had several pairs) so for me are almost unknown, but I remember they were getting quite hot on the amplifier, I touched one during usage by mistake and remember that. LOL


hpamdr said:


> Using dual triode tube in input socket is less precise but change amplification factor and it add some hysteresis wich could be very pleasant and musical, it also allows to use unballanced T1/T2 tube.


So you prefer to use ECC31 in the 6SN7 slot vs a pair in the 6J5 slots? You find the sound to be more precise? I will try this soon because I am also curious. I'll do this also for the Fivre 6N7G.


hpamdr said:


> Curently listening : (Wilco : Ode to joy [2019])
> And give a look on track (4) .....


The track is called "Quiet Amplifier". Nice one.


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## OctavianH (Nov 19, 2021)

Friday workday. No beer today for me, just took the 3rd vaccine jab, but a lot of fun otherwise.





This means C3g in input and then EL3N in both input output positions. Nice! And measuring C3g is fun, you do not see anything. I usually look if something lights up, but here, black box.





On the amplifier, well, with a grid around -3 you are fine, BUT I've seen these jump a lot in current with the smallest grid adjustment. These are dangerous tubes for Eternity. I've seen around 1mA with 0.1 increase or decrease of the grid bias on the tester. More than this, these are "slow starters", I needed 10-15 minutes for these to stabilise. Unlike 6J5 or 6C5 which are in 1-2 minutes stable and measure the same, these need some time like the output tubes, for example EL38. On the amplifier things are smoother, however I am very careful with these. So caution guys, when you try these. Soundwise I will not say more, they sound as I remember them, quite clean and incissive, a little bit towards solid state, but very transparent. But these will take forever to burn in and I am not sure if this sound is my favourite with EL34. I would put something warmer on outputs for these.





Next would be EL3N measuring. Busy day guys.


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## hpamdr

just for your information for El3N : this is my measurement (_each tube measure different) _but this is a good sample.
This give:
 -8.1V g-bias for input (4ma at 180V)
-6.1V g-bias for output  (20ma at 200V)


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## hpamdr

About ECC31 or 6N7G in 6SN7 socket, this is the most conventional is to use single triode in input to have less distortion and noise. 
Anyhow i like my viseaux 6N7GT better in 6J5 socket this make the sound a bit more punchy but a bit less precise in the high. With ethernity this is very subtile..


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## OctavianH (Nov 19, 2021)

hpamdr said:


> just for your information for El3N : this is my measurement (_each tube measure different) _but this is a good sample.
> This give:
> -8.1V g-bias for input (4ma at 180V)
> -6.1V g-bias for output  (20ma at 200V)


Your EL3N measure a little bit better than mine (some of mine, because I have 6). I was unpleasantly surprised to find out that some of them are measuring quite differently.





After almost 2 hours of fighting, trying and so on I made 2 decent pairs. I measured each at 2 operating points (4mA @ 180V and 20mA @ 200V) and found that one which is stronger at one operating point is not as strong on other. You would expect that you measure all once and then just change voltage and that's it, direct proportionality. Well, crap happens. NOT! So I had to try a lot of combinations to see how these pair better. Anyway, the best compromise was for me, this measured directly with the Voltmeter on the amplifier:
- input -6.4V for 4mA (on Duovac I had a little bit more, like -6.5)
- output -5 for 20mA. (on Duovac I had a little bit more, like -5.5)
Other 2 measured stronger, but not close. One was indeed around -8 like yours and one -7.x... I do not remember.

Anyhow, the picture which makes our eyes smile:





The tube on the front in the left was "cosmeticized" by me by removing red paint which started to fail on the base to look nicer. It can be seen before in the other picture on the left. So yes, I HATE this red paint. I also hate the socket these use, the only advantage I can see is that you cannot put a tube wrong in the adapter because it is asymetrical, otherwise, nothing.

Soundwise, of course, not enough time, I barely found time to measure and pair and test and so on. I liked what I heard with EL3N with EL34 on the output, I will investigate this more. This 4 x EL3N combo is for display. This is too much for me in terms of romanticism and a kind of fake soundstage these provide. The rule of contrasts is good here, so I will try to make other combos and not use them like this.

Well, that's it for today, I have listened until now to my equipment, now I will start to listen to music. But first I'll make something with these to fix the signature, so one of the pairs has to go.

PS. I've read about some Tungsram EL3N on these threads, at other amplifier builder, but the people who tried them definitely prefer the Philips, so I guess that's it with EL3N. I am a little bit curious about EL3 (straight glass) but I will not invest a lot in these, at least not with this kind of base.


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## hpamdr

OctavianH said:


> Your EL3N measure a little bit better than mine (some of mine, because I have 6). I was unpleasantly surprised to find out that some of them are measuring quite differently.
> 
> 
> 
> ...


The paint is protection against RFI it is also a Philips "Red tube" marker. 
For me EL3 are not as good as EL3N they also use more current for heating. The Philips and Dario are the most reliable and usually with a constant building quality. About Tunsgram and Mazda many tube measure different and the slope of the curve can differ (more than Phillips) so making a good pair is tricky without measurement tool or curve tracer.  The one I own are also more sensible to RFI than the Philips one.
Phillips and Miniwat green paint are my preferred, after visseaux 6M6


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## OctavianH (Nov 25, 2021)

After a few days wandering on EL3N and C3g territory I have returned to different combos based on EL34. It is clear to me that the best I could obtain for Verite and my musical preferences was always gravitating around EL34. This time the Philips EL34 xf5 doube-D getter (L1L date codes) with Mullard ECC35 (rebranded Zaerix, no date code visible or at least I could not find it).





This is a combination I like a lot, the xf5 being detailed but a little bit dry and here ECC35 comes with a warm somehow euphonic presentation and brings back what I call equilibrium. And when I am bored with this, the Tesla EL34 double angled O-getters comes into play, but those are more aggressive and somehow musical, so we need to put the Brimar 6SL7GT CV1985 into play. Less warm than the ECC35 and more mid forward, compensates what the Tesla EL34 adds. As usual, every combo is a compromise, you add something, substract something, and somehow in the end the result is in equilibrium. I was never a story teller, nor a good describer, but these 2 combinations are, most probably, the endgame for me. The rest of the tubes are just there for other headphones to try or just for experimenting. I can live with these 2 combos forever, at least for these headphones.

What next? Well, I have some homework left to do: EL156 and 807. Then maybe 6C4 via adapters to 6J5? Someone tells me those make sense to be tried. We will see, at the moment things are perfect with these 2 combos I've mentioned. I am at the end of the road in trying new types, I do not want to explore more because I found what I was looking for at the beginning. In this hobby it is important to know when to stop, or at least to try this. New Year resolution? Well, enjoy more the music and not your equipment. Sounds good, until next time I start to dig on Ebay. LOL


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## mordy

It is a very happy feeling when you finally find what you were looking for.
But...
Then perfection becomes the new normal.
And then it gets a little boring.
And then the upgrade bug bites again.
IT NEVER ENDS!

But if you have willpower, you could stop at that stage.
At least for a while LOL!


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## OctavianH

You are right. I say more than this, there is no perfection. I think these are only different faces we put to our music. Most probably these are different than what the production engineer wanted, than the band wanted and even than other listeners want. But for us, at a point in time, it is the best we think we hear. After some time, this becomes boring and indeed, we start all over again. Even in time, we start to hear differently or want something else, and the same combination will not have the same effect.


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## mordy

OctavianH said:


> Your EL3N measure a little bit better than mine (some of mine, because I have 6). I was unpleasantly surprised to find out that some of them are measuring quite differently.
> 
> 
> 
> ...


I do want to point out that the EL3N requires an enormous amount of time to burn in - something like 400 hours!
And don't bother with Tungsram made EL3N - dull and boring sounding.


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## mordy

OctavianH said:


> You are right. I say more than this, there is no perfection. I think these are only different faces we put to our music. Most probably these are different than what the production engineer wanted, than the band wanted and even than other listeners want. But for us, at a point in time, it is the best we think we hear. After some time, this becomes boring and indeed, we start all over again. Even in time, we start to hear differently or want something else, and the same combination will not have the same effect.


I didn't want to sound discoureging at all - music gives us all tremendeous pleasure, even in situations where the sound isn't even near perfect.


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## OctavianH (Nov 25, 2021)

mordy said:


> I do want to point out that the EL3N requires an enormous amount of time to burn in - something like 400 hours!
> And don't bother with Tungsram made EL3N - dull and boring sounding.


This means I am far away from the real potential of EL3N. I have to admit I never exceeded 60 hours with any pair (input or output). No problem, I have them here and I will continue to listen to them because there is something I like about them. Thanks for letting me know about this, I never read about such long burn in for EL3N even if I read almost everything I found about them.


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## triod750

mordy said:


> And don't bother with Tungsram made EL3N - dull and boring sounding.


Maybe they just need 4000 hours of burn in? Try it - you might like it!


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## mordy

triod750 said:


> Maybe they just need 4000 hours of burn in? Try it - you might like it!


I read somewhere that the Elrog 300B tubes never burned in....


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## mordy

triod750 said:


> Maybe they just need 4000 hours of burn in? Try it - you might like it!


Sorry - dull and boring and stays like that.


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## triod750

mordy said:


> Sorry - dull and boring and stays like that.


So you used them for 4000 hours to be sure? I'm impressed by your dogged style!


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## OctavianH

Being very busy with my gaming rig which suffers dramatically changes and upgrades, I have kept Eternity off for a few days. So this is a rare photo where Eternity is not turned on.


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## OctavianH (Nov 27, 2021)

Well, we should not let such a nice amplifier unused. So today I will give him some attention (by the way, question for native english speakers: Why do you call your amps "she"?).





I decided not to promote heavy metal again but I will post a nice track which is a symphonic version of a track on the latest Swallow the Sun album, quite good one:



This is a great finnish band and this reminds me of Helsinki, which I have visited this summer. I remember I walked into the first pub somewhere near Senate Square and it was Black Sabbath with Ozzy at maximum level. Near the bar there were some Iron Maiden branded pinball machines. I had to try 3-4 beers there. Nice town and nice musical preferences of the inhabitants.


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## OctavianH (Nov 29, 2021)

In Venice there is still summer. A good reason to abandon Eternity for a few days.





But when I return many things will happen: EL156 adapters are close.

Later edit: These boats they call "gondola" with a chair inside them were always a little bit strange to me, but others seem to enjoy them.


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## David222

OctavianH said:


> Being very busy with my gaming rig which suffers dramatically changes and upgrades, I have kept Eternity off for a few days. So this is a rare photo where Eternity is not turned on.



Dark Roast ?


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## OctavianH

David222 said:


> Dark Roast ?


If dark roast is a black coffee then yes.


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## OctavianH (Dec 5, 2021)

After a week of pause it is a good time to put Eternity to work again. And my CD Transport needs also some attention. Several months I have listened exclusively from my PC via the JCAT USB card.





Every time after I take a break for more than 2-3 days, when I return, I have a feeling that nothing sounds as it should. I hear lack of coherence, everything sounds dull, unexciting and somehow diffuse. I always start to investigate and in the end the only conclusion is that I need some hours to get used again with my headphone line. And this happened almost after every vacation. At first I thought it is the DAC USB connection which might be problematic, it is a good excuse, then maybe the tubes need some time to settle again, tube amps are vintage technology and need after all some time to sound as their best. But in the end, in the latest years I realized that our brain takes a break and needs again time to adjust. I think this is the major reason for the differences in expectation vs what I hear after a holiday. I have no idea if others have this problem or if someone found a scientific explanation. I just know that I needed 2 days to start enjoying again my music and this was not the first time I had this problem. Of course, another thing which is important to mention is that holiday involves travel and when you return you are tired and this might again adjust your perception.

Now, regarding CD playback vs USB playback. Well, in the past (Qutest and 2Qute era) I was putting Toslink from the CD Transport on the 1st place vs FLAC via Foobar on USB input of the DAC. I use here a QED Reference Toslink purple cable. Later, when I switched to TT2 and M Scaler, I started to enjoy more the USB input. I have no idea why, but now I think I prefer USB vs optical from the CD. For me it sounds more "musical" while the optical input sounds more clinical and lifeless. But judging how much our brain adjusts I have no idea if I really hear what I hear. I guess it just does not matter as long as you're happy.

All is good when it ends good. And tomorrow I will try the EL156 in Eternity. I really look forward.

Later edit:

Incredible artwork on the latest Iron Maiden album. Really good stuff.


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## OctavianH (Dec 6, 2021)

The story of EL156 will take longer than expected. I bought adapters from Deyan and also some ceramic ones from Ebay. The reason was that I wanted to compare them. These ceramic ones are good for "heat management" and I wanted to have as spares to the ones Deyan makes. Today I've received the adapters from Hong Kong and their quality is below my expectations. From 4 pieces only 1 adapters fits the tube properly. More than this, all have a small PCB inside for wiring which some purists normally avoid.





Here can be seen the problem of 3/4 adapters:





The reason is, at least what I was able to see looking inside the adapter, that they wired on top of the PCB so I think that a part of the wires are obstructing the tube pins. Well, I will not put these on my amplifier and wait for the pair from Deyan. I can start to fix these, but honestly I am dissapointed. So be careful guys when ordering adapters. The problem of this seller was, in my opinion, that the made these without trying an actual Telefunken EL156 in it. So he wired, measured and said "works". But also this kind of socket is problematic, like the EL3N one, it reminds me why I wanted an amplifier with octal sockets and no adapters, and I was wise for that.

*Later edit: *The wires are not obstructing the pins, I was wrong assuming this. Answer is 2 posts below: a resin inside the adapter obstructing guiding pin of the tube.


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## UntilThen

I've no problem with these made in China ones. Tubes go in with a nice click and extraction is easy.


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## OctavianH (Dec 6, 2021)

UntilThen said:


> I've no problem with these made in China ones. Tubes go in with a nice click and extraction is easy.


Yours seem fine. Well, then I just advise people to avoid ceramic ones. If 3/4 have a problem, I think it makes sense to warn people. I will open them and try to fix them when I will have some time in the next days. However, all these sockets have the same Y10 socket:





I would not remove these adapters from the tube often, better to buy as many as tubes you have, because that grip becomes problematic. I had this problem at some EL11 sockets in the past and I had to use a small screwdriver to make them connect better after 1-2 tube removals.


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## OctavianH (Dec 6, 2021)

I have investigated further and found the problem. It is not related to the Y10 socket itself, but to a resin he put inside on top of the PCB most probably for electrical isolation. That resin obstructs the guidance pin of the tube to enter complelety. I tried to open the adapter, but everything is so tight glued so I have no chance.





I will think further how to make that hole deeper so the central guidance pin of the tube will fit properly. Anyway, I have a feeling I will damage these during my actions. So beware guys, those metal base from here are better, it seems.

*Later edit:* The resin is almost undestructible. So "drilling" in it is not very easy. But this Y10 socket is also wrongly designed, because it allows people to make "shorter" adapters without forcing them to mantain the guide key length.


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## OctavianH

The day of the Fivre! The Fivre 6SL7GT with Telefunken EL34.





Telefunken EL34 are crystal clear but too audiphile for me, so we add some sugar on top. Some italian sugar. The Fivre 6SL7GT has a lot in common with Fivre 6C5G. So I am more and more into "house sounds" instead of tube type sounds. I find more and more similar different GEC/Fivre/Mullard tubes regardless of their type. Hell knows if I am right or wrong since there is no right or wrong in this hobby, everyone hears differently.


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## triod750

OctavianH said:


> So I am more and more into "house sounds" instead of tube type sounds.


Gibosi often mentions this.


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## triod750

And the question is; from what emanates house sound?


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## OctavianH

triod750 said:


> And the question is; from what emanates house sound?


Well, my assumption is that the manufacturing process or maybe some materials used. I do not know enough about tube manufacturing to tell this. All I can say is that I found similarities between several tube types from the same manufacturer.


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## triod750

OctavianH said:


> Well, my assumption is that the manufacturing process or maybe some materials used. I do not know enough about tube manufacturing to tell this. All I can say is that I found similarities between several tube types from the same manufacturer.


Agree about the probable causes but this is not enough. I want to know exactly what and why. Go back and research and return with a complete answer. You have the rest of the week to come up with this, so take your time   .


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## OctavianH

triod750 said:


> Agree about the probable causes but this is not enough. I want to know exactly what and why. Go back and research and return with a complete answer. You have the rest of the week to come up with this, so take your time   .


I am, unfortunately, on a dead end here. So thinking as a project manager, I have to save resources which will be spent in vain. So I will just continue to listen to this very nice combo, while drinking a beer, instead of starting something which will, for sure, fail. But I am also very curious about this, let's hope someone will enlighten us.


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## triod750

Welcome to the club, Octa, very welcome!


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## OctavianH (Dec 15, 2021)

I gave around 60 hours to Fivre 6SL7 and the Mullard EL34 xf2 and realized these complement each other in a very special way.






Mullard EL34 xf2 have some laid back sound, combined with some "velvet mids" of the Fivre 6SL7. A nice and pleasant sound, cozy somehow. That feeling of a jazz evening in your favourite pub. Well, misses some of the "bite" of the Tesla EL34 which are more aggressive but still, a nice combo on Eternity. For a Sunday evening this is perfect, but tomorrow I'll throw some Tesla EL34 to bring us some aggression.


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## OctavianH (Dec 15, 2021)

For the KT88 experts, I see already a second pair of Gold Lion KT88 sold on Ebay, for example this one. The previous pair went around 2xx EUR but I think that the pair is a chinese one like this and not an english NOS one. We can see here some decent pictures of a NOS Gold Lion KT88. I have not investigated a lot, I am not interested in them, but something is "fishy" here about these Gold Lions NOS KT88. Does anyone know more?

Later edit: I think there is a dedicated thread about these. I forgot about it. I'll post there maybe someone knows more.


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## OctavianH (Dec 16, 2021)

The moment of remembrance. Yesterday one year ago, on 15th of December 2020, I have wrote my first message to Tomas to advise me about a new amplifier. Because I did not knew exactly what I wanted from him to build, I tried to describe what I am searching for. There were several ideas, like an Oblivion or Citadel with KT66 as outputs. In the end the result was Eternity, which I think is quite unique on the line-up of UltraSonic Studios: tube rolling with manual grid bias. At that time I had no idea what this means.





Later edit:

On 20th of April 2021 I was comparing these:


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## OctavianH (Dec 17, 2021)

Friday Beerday! And after a week full of stuff I definitely need one. This evening I will spend some time with the EL34 which does not look like an EL34.





These Sophia Electric EL34 are a little bit clinical and dry. I guess they want to provide that low distortion precise sound, but for me it misses something. Even the build quality does not impress me, the plastic base seems cheap, these are very light tubes, like a feather. Compared with the Telefunken EL156 which are big, heavy and built like a tank these seem to be a joke. But they are beatiful with that blue glass.

Clinical and dry? This means today I'll add some nice Mullard ECC35 trying to bring things a little bit in the middle of both. Let's see where this goes. It is my only EL34 pair which I think it is still on production, so let's hope I'll find a nice input combination for it. We need to give a chance to the newcomers.

Later edit: The ECC35 could not warm enough and bring some life into the Sophias. Damn, I had big expectations from it. Well, no problem, we need bigger weapons and since we have some blue, we need to add some red. If I was a painter combining these I would most probably obtain the colour of 2022! Very Peri.





Yep, now things seem to be better and since EL3N biases the same in 6J5 slots as 6J5 tubes, I can use these on my fixed bias setting. So we press a button and EL3N works, magic! This was one of the best custom features I asked from Tomas. To have a tube rolling amplifier which has a fixed bias switch. For some tubes you know that bias similar with the 6J5, you just switch to the predefined bias setting and that's it. No voltmeter needed. I know I have there -6.2V on input and -21.4V on output and that's it.


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## OctavianH (Dec 18, 2021)

The parade of the shinny grey glasses. Philips EL3N and Psvane KT88-TII.





I was not happy about the Sophia Electric EL34. Tight and low distorted sound but somehow lifeless. When I added EL3N it sounded better, warmer but condensed somehow. I always perceive the "wideness" and "airy" presentation somehow related to high frequency reproduction. That combo was good but lacked in the top area. So I have decided to put some KT88 on outputs. This reminded me how different we can train our brain to evaluate. I will explain: I have tried the same combo in May and said that it was too warm. Now it seems perfect. The only difference was that in May I used a double adapter to 6SN7. I expect that tubes sound similar in 6J5 slots or in double adapters to 6SN7 as far as the operating point remains similar. But... now I like this better than in May. And another thing which is interesting is that I like the High Z position of the impedance switch more than the Low Z position I always used for Verite.


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## OctavianH

Heavy duty.


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## OctavianH (Dec 18, 2021)

Good and bad news. The good news is that my adapters for 807, EL156 -> KT88 and ECC31 -> 6SN7 arrived.





The adapters from Deyan are very good quality. Nothing to object here, above expectations. The fit of EL156 is perfect, the wire for anode top cap of 807 is very flexible, the top cap inserts very nice, much better than all my other adapters with top cap where the wire was of lesser quality and the top cap was smaller and the fit was not as good. I am very pleased about them and you know me that I am picky and always complain. Here nothing to complain about. The socket for 807 has no guiding pin but because of the placement of the 5 pins you cannot wrongly insert it so it is fine.

So, after inspecting these, I measured my EL156 and found a perfect pair.





Bias for 200V/20mA is around -13V. I had -12.4V/-12.9V/-13V/-13.5V so I guess assuming a -13V as a medium value is true. But after I measured and put these on the amplifier some things happened which made me postpone the listening session. First, the current in them was raising fast but not uniform, around 10mA decreased a bit, then started again to grow. With the headphones removed I wanted to check both channels and used the meter switch, this made the needles of the meter jump a lot in both directions.  I said "Fine", this happens also with EL34. So I have decided to insert the headphones and put some music. The sound was extremely powerful, fast and full of energy. A little bit dry but somehow I felt they fit in the "house sound" of the Telefunkens (similar somehow with EL34 but here we are in a Ferrari on a highway while with the EL34 we are in a Buick enjoying a glass of wine). A fast powerful sound, a little bit dry but I have not heard such an energetic sound since KT150. Of course, take this with a grain of salt, these are not impressions, just a small description of 1 minute of listening because very soon I started to hear crackling in the headphones, then some electric noise. I tried also to switch from Low-Z to High-Z and again big variations of current on the meters. I started to have the feeling that everything I touch impacts that. So I set volume to 0 and the amplifier was stopped. I will postpone my EL156 journey until further investigations are made, to be sure Eternity does not take any damage or that I am missing something.

@SonicTrance Do you have any idea why EL156 are acting like this on the amplifier? Why impedance switch impacts current through the tubes?

And now the nice part: RCA 807! This are a gem guys. For 200V/20mA I need around -19V so these bias close to KT66 (more or less around -20V).





But about the sound: guys, these have KILLER bass. Fast, punchy and articulated. It hits hard and fast. Verite rarely sounded as articulated in the low frequencies area. The overall tone is relaxed, warm but the bass is incredible. I hear double pedal and every hit of the drummer in my head. I think these remind me of EL39 but I don't have at the moment an EL39 pair to compare. I wonder how this bass can sound on a planar, but I have no planars at the moment either. Of course Philips EL3N are not a good pair for these, these need neutral inputs, but at the moment this is what I had on the amplifier. Great tubes these 807, I will let them here and check them again after around 100 hours. For sure, I have some preliminary impressions, but I doubt this bass will disappear during the next hours, it will only improve. After hearing these I have decided to check also the 5933 type. I think 807 (and maybe 5933 because they seem to be in the same family) are a very good match for the signature of Eternity warming it a bit and adding very good quality bass. I would pair these with some "incisive" neutral tubes to obtain a more equilibrated signature than with EL3N. But this will be done later, at the moment I will enjoy this fast laid back sound.


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## SonicTrance

@OctavianH 
Different tubes won't affect the output impedance of the amp. But, output tubes with low rp will drive the OT primary better than tubes with higher rp. As long as rp is under 1k (triode strapped) it's fine.

If the current meters aren't stable I'd not use those tubes! They're most likely leaky. Meaning they have low resistance from one element to another. You might be able to test that on your tester?
Anyway, don't use them is my recommendation. If one of them shorts out completely it can definitely hurt the amp.


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## OctavianH

SonicTrance said:


> @OctavianH
> Different tubes won't affect the output impedance of the amp. But, output tubes with low rp will drive the OT primary better than tubes with higher rp. As long as rp is under 1k (triode strapped) it's fine.


Interesting.


SonicTrance said:


> If the current meters aren't stable I'd not use those tubes! They're most likely leaky. Meaning they have low resistance from one element to another. You might be able to test that on your tester?
> Anyway, don't use them is my recommendation. If one of them shorts out completely it can definitely hurt the amp.


Yes, I will be very careful, I have tried here hundreds of tubes and no pair caused problems when using the impedance switch. I will read the manual of the tester to see what I can measure and how, until now I used it only to determine grid bias.

Thanks for answer!


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## OctavianH

Trying to investigate if I am crazy or these 807 really deliver incredible bass I have started to roll inputs. And yes, the bass is there, belongs to 807, it is tight and punchy. The amplitude of the punch is controlled also by the nature of the input. EL3N being warm were adding to the already great bass of 807. With more neutral counterparts amplitude decreases but the signature remains there. Great tubes, I was never so excited in a long time.

But back to more interesting things. When I was discussing with Tomas the socket placement of the input tubes, because of the small footprint of the amplifier and the VU meter placement on the front panel, we agreed that the 3 input sockets (single and dual triodes) will be close and I will not be able to use 3 ST shaped inputs. In all my pictures until now I have combined straight glass and ST-shaped. But today, since my ECC31->6SN7 arrived, I was able to try a combo of ST-shaped 6J5 with Mullard ECC31. Due to the fact that these are smaller, they fit.





My Fivre 6N7G will not fit here because it has the size of the Mullard ECC31. But Cossor 6C5G sits nicely near the ECC31 which is on top of the adapter. Ok, I will move on to other inputs, just wanted to show you that 3 ST-shaped tubes might work in Eternity if the double triode sits on an adapter. And I have a feeling GEC L63 grey glass works the same. Now, it does not make sense to keep such expenssive tubes on the amplifier in normal listening sessions, because depending on the input switch some of them are just lightning. But from time to time, it is nice to use some beautiful tubes. In this picture, only the central ECC31 is combined with the 807. The 2 single triodes are just lightning to look nice.


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## OctavianH

Ok, enough about 807. I tried several inputs and stopped at ECC35 which complements them very good. But for a nice picture I've chosen Fivre 6N7G.






And the low light test:


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## triod750

SonicTrance said:


> They're most likely leaky. Meaning they have low resistance from one element to another. You might be able to test that on your tester?


How do you test for this? What kind of tester is needed and how is the test performed?


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## SonicTrance

triod750 said:


> How do you test for this? What kind of tester is needed and how is the test performed?


Most old tube testers have this feature. It's either called "leakage test" or "shorts test".  
On my Heathkit TT1-A the leakage test is done at 125VDC with a internal ohmmeter in series with the elements under test. You then switch between all elements while testing. The meter can detect as high as 10Mohms. It should be infinite resistance between all elements of the tube so any meter deflection indicates some leakage.


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## OctavianH (Dec 20, 2021)

SonicTrance said:


> Most old tube testers have this feature. It's either called "leakage test" or "shorts test".
> On my Heathkit TT1-A the leakage test is done at 125VDC with a internal ohmmeter in series with the elements under test. You then switch between all elements while testing. The meter can detect as high as 10Mohms. It should be infinite resistance between all elements of the tube so any meter deflection indicates some leakage.


My tester has a short-circuit led, and in the manual I have:





It is true that for all 4 EL156 the led flashes, but there is no steadily light. But flashing happens to almost all my tubes. I tried yesterday to use the other pair of EL156 and I had problems again, not like those but current somehow started to rise, decrease, rise. I stopped and removed them, it is not so important to me to use all possible tubes in the world. I suspect it might be a compatibility problem of EL156 with this hybrid modern/classic tube design instead of having 4 tubes with problems. They were tested by the seller and also look fine on my tester (even if it is a small and simple one). I will store these tubes and wait to see if others can use this type on other amplifiers, the problem is that as far as I know there are only 2 Eternity built and 1 Infinity which are candidates and I doubt somebody will try these. If these work on Odyssey it does not completely convince me tubes are faulty, that's a completely different design.


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## SonicTrance

OctavianH said:


> My tester has a short-circuit led, and in the manual I have:
> 
> 
> 
> It is true that for all 4 EL156 the led flashes, but there is no steadily light. But flashing happens to almost all my tubes. I tried yesterday to use the other pair of EL156 and I had problems again, not like those but current somehow started to rise, decrease, rise. I stopped and removed them, it is not so important to me to use all possible tubes in the world. I suspect it might be a compatibility problem of EL156 with this hybrid modern/classic tube design instead of having 4 tubes with problems. They were tested by the seller and also look fine on my tester (even if it is a small and simple one). I will store these tubes and wait to see if others can use this type on other amplifiers, the problem is that as far as I know there are only 2 Eternity built and 1 Infinity which are candidates and I doubt somebody will try these. If these work on Odyssey it does not completely convince me tubes are faulty, that's a completely different design.


Your tester only tests plate to other elements. That doesn't tell you if it's leaking from grid to cathode for example.

All tubes, that can have the operating point 200Va, 20mA, work in Eternity. Nothing special about the EL156. I still say it's bad tubes.


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## OctavianH

SonicTrance said:


> Your tester only tests plate to other elements. That doesn't tell you if it's leaking from grid to cathode for example.
> 
> All tubes, that can have the operating point 200Va, 20mA, work in Eternity. Nothing special about the EL156. I still say it's bad tubes.


No problem, I can accept that. Good that Eternity works well and has not suffered any damage from them, this is what it matters to me.

Back to RCA 807, in this case with Siemens C3g. This is a good pairing. To sell a pair of C3g is a beginner's mistake and I've done it. These take forever to burn in and if you sell them, you will for sure want them back and wait an Eternity to make these sound ok on Eternity. So never sell any Siemens C3g. Simple.


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## OctavianH

Christmas has to be spent in the family. My tubes agree with that. RCA 7N7 with RCA 807. The RCA family.


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## OctavianH

Circling through drivers, to get a taste of these 807. Now Ken-Rad 6F8G. This amplifier is quite neutral, clean sounding so warmer and full bodied tubes like 807 are complementing its signature very good. I start to wonder how a Citadel would sound (the "cleanest" design from UltraSonic Studios) with 807 as outputs. 

@SonicTrance Is it possible to build a Citadel with 807 as outputs?


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## triod750

Your commitment to no adapters and no top contacts is showing in full glory. Congratulations!!


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## OctavianH

triod750 said:


> Your commitment to no adapters and no top contacts is showing in full glory. Congratulations!!


You are, as usual, right! I am not proud of that and honestly this is exactly the thing I am thinking for already 3 days. I will enjoy these 807 which are an incredible match for Eternity and then most probably return to EL34. I still dream about an amplifier with octal socket and a user which does not need any adapter. But my curiosity made me try these, and here I am. I still consider octal socket the best and no top cap as optimal.

As the proverb says: Curiosity killed the cat.


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## triod750

It is the result that counts, not the way to get it. Enjoy your tubes and your music whatever it takes!


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## SonicTrance

OctavianH said:


> Circling through drivers, to get a taste of these 807. Now Ken-Rad 6F8G. This amplifier is quite neutral, clean sounding so warmer and full bodied tubes like 807 are complementing its signature very good. I start to wonder how a Citadel would sound (the "cleanest" design from UltraSonic Studios) with 807 as outputs.
> 
> @SonicTrance Is it possible to build a Citadel with 807 as outputs?


Definitely possible! I use 6P7S's at the output in the silver Citadel. The 6P7S is very close to the 807.


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## OctavianH (Dec 21, 2021)

As many observed, I avoid to make statements, more to give hints about what I like or not. The reason is that I think more and more that every system sounds in a different way, that everyone's preferences differ and in the end you cannot make a purchase based on an impression of someone or a review. I stopped reading reviews several years in the past and I do not regret it. I never read something which matched my perception. But I am a honest person, I usually say what I think about tubes and equipment. I do this because I think the reason we are here and we write is that we need to help each others, and if we start to be polite with several brands we loose this reason. I am not polite, but I try to be not rude. In the end, let's hope we all get what we expect from our equipment.

For me the biggest victory is not to find out that a very expensive tube sounds good. In the end this is what we expect when we buy it. The biggest victory for me is to use a cheap tube on a good amplifier and obtain the sound I dream about. I strongly think that the price of tubes is based on demand and stock and not on sonic quality and a tube nobody gives a "heck" can be in the same league as the most expensive one. This is why I love Tesla EL34, those rock on proper amplifiers. And this is why I started to love RCA 807. I have no idea if other 807 sound the same, but this pair, even if it needs an adapter with top cap which is a minus for me, is cheap and has something I will not renounce. This is a pair I will never sell, a pair which tells me something and I will aways keep close on this amplifier.

Oh yes, during holydays I start to be more philosophical. I guess it is related to the new year achievements and so on. I always think at the end of the year about what I have done, what I wanted to do and what I will do from now on. Last year I decided to write to Tomas about a new amplifier, and this year proved me I was not wrong. Let's see what my self introspection will bring me this year.


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## triod750

It's inspiring to follow your achievements. Keep on keeping on! And don't stop thinking and sharing...


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## OctavianH (Dec 21, 2021)

triod750 said:


> It's inspiring to follow your achievements. Keep on keeping on! And don't stop thinking and sharing...


This thread was somehow my personal blog. I started it before owning the amplifier and then just shared my personal opinions about something nobody was able to test. There is a very nice and experienced user of Eternity, which has a more evolved version than mine, which can use 12V tubes and he enjoys it. But besides that, we are 2 persons in the world using this type of amplifier. It is directly derived from Infinity, somehow similar with Oblivion and Citadel, but still different. And very much different from Odyssey. I am fully convinced all these are great amplifiers and each of them have their own merits. I want to thank a lot to everyone reading this and had enough patience for my off topic way of sharing information. In the end we are what we are, we love music and, in my case, beer and we want to combine fun with pure information. I consider this a hobby and try to approach in a relaxed way. I have a full time job where I need to be very precise and sobre, I hope at least when listening to music I can allow me to drink a beer or speak for fun. But in the end I guess people enjoyed my journey and let's hope other people will learn something or avoid mistakes while reading my experiences. This is what it matters in the end: fun but also some educative purpose.

I plan to write again about Eternity on April, after one year, and bring some impressions about long term sound, tube rolling and overal impressions. I will also remove some parts of the "story" which are not so important for other people. Let's hope it will be readable and useful. Until then I will prepare myself by trying more and more and learning more and more.


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## jonathan c

OctavianH said:


> Christmas has to be spent in the family. My tubes agree with that. RCA 7N7 with RCA 807. The RCA family.


Since it is the Christmas season, any tubes with little snow villages inside?…


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## OctavianH

jonathan c said:


> Since it is the Christmas season, any tubes with little snow villages inside?…


I guess this is a GE 6SN7 but I will try it. I know many of you like GE tubes.


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## OctavianH (Dec 21, 2021)

I tried "someting different" just to see how that sounds:





Well, this is good but it is not my speed, intensity nor type of music. This makes me realize how far I am from others expectations, when describing something. I like a lot Michael  Jackson and Depeche Mode, but honestly when I describe something here I am around this kind of sound:



So this tells me how irrelevant are my impressions to others.


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## triod750

Even if your music should be irrelevant (mind you, I don't say it is), neither you or your impressions are. We can always learn from each other, and do.


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## OctavianH

triod750 said:


> Even if your music should be irrelevant (mind you, I don't say it is), neither you or your impressions are. We can always learn from each other, and do.


I fixed the problem going back to EL3N as inputs. Even if Tomas advised me to use tubes as they were intended to be used, EL3N in input is incredible, especially on these neutral amps.


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## OctavianH

Merry Christmas! Ah, it is tomorrow, well not for everyone.





My quest for planars continues, this time the japanese D8000. The unpacking is an experience, it is a big box composed of several smaller boxes. It was a complete puzzle for me to put those back and reform the box to store it. I tried this year the Ether 2 and Thekk. Now it is the time of D8000 to be tested. From what I hear results are promising, but as always, only time tells the truth. More to come.


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## OctavianH (Dec 23, 2021)

Trying to decypher a new pair of headphones is always a challenge but also a pleasure. I will have a definitive opinion on these in months, but I can say from the start these are close from what I expect from a headphone. I am on the neutral-warm side and these are somehow close to the Verite. The timbre is better on Verite, that wood sound is growing on you and makes you feel a more lifelike sound. But the speed and bass of D8000 is better. Somehow this is more a dynamic vs planar issue. Mids are sweeter on Verite, darker, somehow a more cozy sound while the D8000 is more in your face and aggressive. Resolution is great on both, but I will keep a final opinion until I will try these with a proper cable. I am more on the silver cables and these D8000 with stock cable sound more on the copper area for me.





Coming to build quality, D8000 beats Verite. But this is a more personal approach. I was never into wood or colours and limited editions. I always prefered solid headphones which make you feel they are indestructible and D8000 looks like that. It is built like a tank and comes with a solid headphone stand which is excellent. By the way, I never understood the carying case for other high end over ear headphones, since I would never take such a pair on the road with me. So a headphone stand is a much better choice in my case. The cable is decent and flexible, while the 6.3mm has 3m and it is a little bit too long for them in my setup. It is copper and does not please me a lot but I will replace it soon with a Noir Hybrid from FAW. And I have a problem also with the earpads, the fabric is strange and they do not quite feel sturdy. But the rest is rock solid.

In short, very interesting headphones, I strongly think to add these to my stash but since my quota of headhpones is 2, which one will go? T1.2 has a historical meaning to me and since it is newly refurbished with leather headband and new earpads it looks like brand new. Verite sounds great and it has great timbre but I have a comfort issue with it. Time will tell, I can keep all three but I will think about it. Idea was to have a planar and a dynamic to combine advantages from both worlds.

PS. One more thing I have observed with planars vs dynamics is that planars sound more equilibrated a low levels of volume while dynamics need a decent lever to shine.


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## triod750

Suggestion: change your hp quota. One amp, three pairs of headphones and five tubes .


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## OctavianH

Here's the trick: I never put a quota on tubes.


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## OctavianH (Dec 26, 2021)

Christmas morning with a big cup of coffee. Some music goes well with this and also some writing. So it is a good time to share some thoughts about these D8000. I will not be on the technical side analyzing graphs (I do not believe graphs can perfectly describe a headphone anyway) nor compare songs and other headphones and so on (except some minor remarks at the end in relation to VO). There are more experienced people to do this and this has been already done at a very good level here or on the D8000 thread for example here. I am just an amateur and I focus on impressions, perception and so on. I will not say a lot about the sound either because it much too early, but I will, however, share some impressions which will be useful also for me in the following months to compare. And all related to, of course, a part of the subject of this thread: UltraSonic Studios Eternity and its synergy with them.

*The amplifier*

At the moment the headphones have around 30 hours and I am fully convinced these are not in the point I completely understood them nor they are not evolving anymore. Many claim on the product thread that they needed hundreds of hours and some of them even months to fully understand and assess these. And I believe them, after 6 months of Eternity I only scratched the surface, there is much more left for me to investigate than I was able to do until now. In the first 2 months I only rolled different tubes and because some of them were NOS I was only able to let them burn in. So I am also far away from a complete vision about the amplifier. However, what I understood about it is that it can be a very resolving amplifier if it is properly paired. Since the signature is on the clean/neutral side, without almost any harshness or excessive distortion, most probably a consequence of the new design, it sounds better with warmer tubes, especially in the output section. The input is only adding a flavour to an already defined taste set by the outputs. So Eternity is like a beef steak with pepper sauce. With different outputs you can make it medium/rare or well done but with the inputs you are just adding a sauce on top. You can exchange the sauce, but the beef steak will remain a beef steak. Yeap, I know, my comparison sounds crazy but this is what I am, the worst story teller complemented with mediocre english skills. And when this is combined with a big cup of coffee instead of a beer I start to write science fiction. But why I told you this: because the signature of the amplifier makes me prefer it with warmer outputs, which add some "flesh to the bones" and also silver interconnects which improve details, soundstage and somehow make these warmer outputs sound more natural to me. I have tried to replace my Neotech NEI-2001 custom made interconnects with some silver plated coppers and the difference was big, in the wrong direction. I know that many do not believe in burn in, interconnect differences and so on and claim that a good cable with a proper electrical connection is enough. In my case Eternity is a different amplifier when interconnected to TT2 by silver.

*Build quality and comfort*

And now back to D8000 after we spoke a little bit about the amplifier. When deciding to add a planar to my collection, and most probably renounce on one of my other dynamic headphones I own (T1.2 and VO), I was a little bit worried about the capability of the amplifier to drive low impedance headphones, synergy of an already clean sounding amplifier with some "synthetic" sound of these type of headphones and in the end, why not, excessive bass which covers the other frequency ranges. Since the amplifier works the best with warmer outputs (EL34, 807, EL3N) I was wondering how a planar respected by all because of its bass quality and quantity can suit on top of these. Ah, and last but not least how this headphone will react to different tube combos.





So these were my thoughts on Thursday evening when the courier arrived at my door. After the unboxing event (which is trully an event if you will ever see the packaging - it took me 20 minutes to be able to put all the small boxes in the same order back into the big box and make them fit) I was quite surprised about the build quality and sense of total customization these show from the moment you take them from the box. Besides the somehow "steam punk" aspect, these have very solid, compact cups and slim earpads and come with a heavy custom shaped stand designed to accomodate them perfectly. The best way I can describe the initial impression when putting them out of the box is: these do not look handcrafted or boutique level equipment, but more a product realized on complex and very precise equipment. Japanese craftsmanship at its finest level. If other headphones look like made in a garrage by a very skilled technician, these look made in a laboratory with very performant equipment. And all seems modular and designed to fit properly and be easily replaceable. So the feeling that you can really repair it or at least replace it builds you trust that this product can be a good long term investment.
But ok, let's discuss also what I do not like about them and this is a very important point since it can be the value I add to the community when describing something. The pros are everywhere in the professional reviews, but the cons sometimes are missing.
First of all the earpads, the fabric these are made of does not please me. I doubt after 2 years of intenssive usage (2 years being the warranty period) these will remain in perfect condition and since this product is not easily found in Europe I will have to see, if I will own them at that time which I will most probably do, where I can get some replacements. Marketed as "expanded foam body with superior breathability and special polyurethane fibres" here it looks to me more as a kind of elastic fabric put over a sponge instead of a memory foam like many other vendors use in the same price range. And besides the durability problem these slim round earpads might not properly accomodate everyone's ears nor be enough comfortable especially if you wear glasses. In my case they are fine but I can understand if others complain or have problems with these. The original owner of the headphones was not able to use them more than 12 hours because of comfort issues. So beware if you know you usually have such problems and to have a better idea I tried to compare them with my T1.2 and honestly these are similar or even an idea smaller inside:





And from the picture we can see also that this kind of fabric attracts dust. When looking to them in normal light you cannot see it but in picture it always shows something. That's it, the earpads are of a lesser quality based on my personal opinion, but they have a good part avoiding heat collection and making these headphones usable during hot summer. A good thing is that they are decently priced, other vendors ask crazy prices for replacements. I have not measured them, I am careful not to touch the earpads with anything made of metal because of the magnetic nature of these drivers and the fear of damaging something. Another thing to be mentioned is that the earcup is moving enough to isolate properly.
The headband is leather and good quality, looks nice and I have nothing to complain about, it is much better in my view (here many might disagree) than the "suspended" ones where you usually have a thick leather which takes the form of your head. I have very short hair and during summer I feel like I wear a leather hat on my head. This one is thinner and more compact, I can wear it a little bit on the back of the head and just forget about it.
Another point is the cable and here I also have a problem which I will present. The headphones come with 2 cables, both OFC, the 6.3mm with a lenght of 3m and the 3.5mm with a length of 1.5m. While being incredible flexible and not microphonic (or at least for me) they are thick, the 6.3mm is too long and heavy. Because I listen closely to my amplifier (and in my case having an amplifier with manual bias adjustment built for tube rolling it is recommended to keep it close and take a look from time to time at those currents or adjust if needed) it happened not once that it hanged on the stand or on my chair handgrip and so on. Since it is heavy and slippery it tends to fell off the surface you put it on. And, in the end, being OFC it does not properly complement the headphones. I have a strong feeling that these headphones with a full bodied and organic presentation would benefit more from a silver cable. In my defense, when Final released the PRO version they replaced the earpads with more durable ones and upgaded the cable, so I guess my complains match the general consensus.
The last point is the headphone stand and here, besides quite liking the idea of a fully custom headphone stand for this uncommon form of headband (the lower metallic part where the cups are sliding) I have 2 problems with it: first is that you need to be quite precise when handling and second that the headphones might fell off it easily. It will take you 2-3 seconds until you properly fit the headphone and if you roll or work like me and listen to music, you make this 10 times per day. And the second part is that the headphones sit on it based on the clamp force and it has no "stopper" in front so if you use a heavy or, in my case, too long cable like the stock one they included, in my usage scenario, you might drag them off.





But besides these, it is decently build, stable and sturdy and half of my problems with it might disappear while replacing the stock cable with one of proper length and weight. This is why, at the moment, I prefer to put them from time to time directly on the table and use the stand only when I take bigger breaks.

And in the end my personal view about the overall level of comfort. Many know that I always complained on this thread about weight and comfort of different headphone brands. Some of my headphones cannot be used during summer because of the suspended type of headband and thick leather which sits on a big part of your scalp. Others had an elastic mechanism which was constantly rising the headphones from my head and I had to adjust them several times during the listening session. So different tries and different problems, at least for me. Surprisingly, these at 523g are the heaviest headphones I have tried in the recent years but still, proved to be decently comfortable, at least at the same level with other headphones from my collection. The reason is that the classic headband and compact earpads make them fit nicely on my head without collecting heat or move when I work at my office. They also do not press or create any kind of discomfort, therefore they pass my comfort cryterias and surprise me judging their weight. Here of course everyone has a different preference and this is strictly related to my perception. If the earpads are not too small or thin for you, I guess you can consider these comfortable and suitable for long listening sessions.

*First 30 hours of listening*

Being almost new, these headphones can be still considered in the burn in process (or brain adjustment, if others prefer to call it like this). I was able to obseve major changes in the first 20 hours and I am fully convinced I am only at the beginning of the road. For burn in skeptics and also in my defense I will describe how the first 10 hours passed. While being busy with Christmas preparation and my last working hours for 2021 I listened to these around 2-3 hours on the same album (not relevant but I will mention it, german thrash metal band Bonded with the new album Into Blackness) and observed some harshness/sibilance in the high frequency area on a specific track. I made a small note about the track and then let them on the stand while doing stuff around. After a few hours I put them back and observed that the midrange and treble smoothened a lot and the bass is more articulated. I said ok, might be, might be not and this is what everyone tells about every headphone. But when that specific track started I remembered the passage and expected to hear the harshness and nothing. I put back the same track and again nothing. So burn in or brain adjustment, these evolve a lot in the first hours and the changes are not subtle. I never observed such big differences on other headphones from my collection in the first hours and I strongly advise extreme patience to anyone who will decide to try them. After hearing how much these evolved and read again others impressions on the product thread, I realized that I will need another 2-3 months to be sure I am able to hear these at their full potential and that my initial impressions with the stock cable are not relevant on the long term. Do not consider to buy these without listening a decently used pair on a headphone show or if you do not plan a long term assessment.

I will not say more about the signature and synergy with Eternity at the moment, except that these have a full bodied and warm sound (some call them neutral-warm but these are quite on the "lightly warm" area on tubes based on my perception) which makes them suitable for long listening sessions but more in the middle for those craving for detail and pure analytical sound. Most probably these sound different on SS amps but I was not curious until now to put them on TT2. Somehow in this matter they are close to VO which I consider a very technical headphone which is able to present you the technicality in a relaxed and pleasant way and D8000 does the same. I read somewhere a very good description that these are somehow "bottom to top" headphones, most probably because of the very tight and punchy bass you first encounter while listening to them. Their signature goes very well with Eternity and the impact of the warmer tubes is not making these sound bloated. I can say more, that these have some kind of transparency which shows more of the nature of each tube than my other headphone pairs, this making them more "picky" with the amplifier or tube combo but also scale more based on the rest of the chain. Being a planar magnetic I was always afraid of a synthetic sound or lack of realism but these proved to be quite "organic" sounding. They are not at the level of refined timbre of the VO but they are close to that and still feel quite "emotional" and euphonic sounding when amplified by Eternity. And they win on bass texture, speed and even slightly on resolving skills. Both are close in the detail retrieval, but these seem to surpass VO and the moment I had this feeling was when trying Siemens C3g with RCA 807 last evening. We know that C3g can be very transparent and resolving in the high frequency area and they added an incredible level of details for me in some acoustical guitar passages or drum solos with cymbals and so on. But while I was impressed by the previously mentioned technicalities, I missed VO on the lifelike presentation of the piano or some female vocal passages. Difference is not big, but here VO wins for me and most probably it is that kind of timbre and natural presentation where it cannot be beaten. Regarding volume levels, I listen to long sessions at around 75dB to avoid fatigue and Eternity can provide that on Low Impedance setting at around 40% of the volume knob. So I am most of the time around 11 o'clock and I am fine.

These are early impressions, I will add a FAW Noir Hybrid to these headphones which will, for sure, take them to another level. I expect a decrease in bass quantity but a wider soundstage (even if the soundstage is still evolving and increasing at the moment and it is decently wide) and more resolution in the treble area. I wonder where these will go with C3g and a silver cable, it might be the best I have heard on a headphone my whole life. I also wonder how these would sound with the PRO earpads because the comparison made on the product thread here made me think it is a useful upgrade. But at the moment I could not find the G-type pads available in Europe. I might invest more time in this after holidays. At the moment I try to focus on the stock provided accessories to have a starting point in assessing upgrades.

What I understood today? That I need a beef steak with pepper sauce, medium rare if possible.
What you should understand is the risk of missing New Year's Eve by reading the whole post.
Over and out. I do hope at least a part of this will be useful to someone.


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## OctavianH (Dec 29, 2021)

The 807 saga continues: the 5933!





Similar with 807, thicker base and straight glass, bias the same and sounds the same, which means good. There are some small differences in sound, more related to "RCA house sound" vs "Sylvania house sound" but that's it. A little bit less bass (do not worry, bass is there but hits not so hard), more extension on high frequencies, maybe a little bit wider soundstage. Anyway both are close, sound quite good, bias at -18.5V on Eternity. Small differences in currents are related to the tubes themselves.





Compared with my pair of RCA 807, these Sylvania 5933 are an "uglier" versions which I bought cheaper but they are in the same league. From what I've read these are a rugged version of 807, otherwise electrically identical, therefore replaceable with the same adapters.





*Later edit:* Since 807 and 5933 are very close to 6L6 (different base with anode top cap but same bias) I wanted to revisit my 2 pairs of 6L6. Result was that 6L6 is good but these are, at least for me, much better. I tried also some 6V6 to remember how I see them. Nope, 807 and 5933 are a different animal, much better for me and this amplifier. 6L6 (at least those I have) and 6V6 do not sound at the same level. Sad but true.


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## OctavianH (Dec 30, 2021)

I investigated today how much "headphone dependant" is Eternity and regarding synergy with different headphones, in my case Verite/T1.2/D8000 things are more or less the same. So basically the same tube combos (or tubes) I prefer for a specific stage remain in top for all headphones. Of course, I might prefer one above the other depending on the headphone I use, but for sure the tube types I put in my top 3 remain in top 3. And I tried before several other headphones (Ether 2/Thekk/AWAS/ADX5000) but I felt the same. You can somehow "force" the signature with some tubes, but you loose sound coherence. Top 3 remains top 3 and those will sound the best with any other headphone. Or at least this is my conclusion for today, of course considering my own rest of the chain.


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## mordy

OctavianH said:


> I investigated today how much "headphone dependant" is Eternity and regarding synergy with different headphones, in my case Verite/T1.2/D8000 things are more or less the same. So basically the same tube combos (or tubes) I prefer for a specific stage remain in top for all headphones. Of course, I might prefer one above the other depending on the headphone I use, but for sure the tube types I put in my top 3 remain in top 3. And I tried before several other headphones (Ether 2/Thekk/AWAS/ADX5000) but I felt the same. You can somehow "force" the signature with some tubes, but you loose sound coherence. Top 3 remains top 3 and those will sound the best with any other headphone. Or at least this is my conclusion for today, of course considering my own rest of the chain.


This has been my experience as well - great sounding tubes sound good with a lot of equipment and with all different kinds of music as well.


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## OctavianH

Happy New Year! 

With 5 days delay... I took a well deserved break.





While still evaluating 2021 I am also making some small plans for early 2022. So, what's next? Well, I'll try some russian 807 because these sell around 10 EUR/piece and I have a feeling they have a lot to say in Eternity's equation. Then, I cannot ignore GEC E3375 which I recently remembered while reading this thread which is an incredible resource for our amplifier. Last step would be for me to try some "small" 9 pin tubes, on input mainly. Here I have no clear idea yet but I am documenting and a starting point is exactly this thread to see what others used and liked. A very big mistake from the past (selling all my tubes for LittleDot MK2 as a bundle with the amplifier) put me in the situation to own 0 tubes of this type. But I'll choose 2-3 cheap ones with potential and try. Ah, since I have around here 4 pieces of Valvo EL11 I guess I'll try them. Good, now that we have a plan, let's stick to it.

A good year, filled with new experiences, to all of you!


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## Isaacc7

OctavianH said:


> Happy New Year!
> 
> With 5 days delay... I took a well deserved break.
> 
> ...


I have a pair of Russian 807 tubes labeled CV124 and sold under the name Firenti. I was led to believe that they were British and was disappointed to find out they are Russian. I tried them anyway and I think they sound great. In my amp they have a big, warm sound with decent bass. Here’s what they look like.


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## OctavianH

Isaacc7 said:


> I have a pair of Russian 807 tubes labeled CV124 and sold under the name Firenti. I was led to believe that they were British and was disappointed to find out they are Russian. I tried them anyway and I think they sound great. In my amp they have a big, warm sound with decent bass. Here’s what they look like.


Some sellers are marketing them as Western Europe but the inverted cup getters are somehow typical for russian tubes. These seem similar with the ones I am waiting to try and I expect them to be delivered on Friday. I have big expectations that these will sound good. At the moment enjoying RCA 807 and I have also a pair of Sylvania 5933 (direct replacement) which sound good and bias the same. These 807 are a gem!


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## Isaacc7

OctavianH said:


> Some sellers are marketing them as Western Europe but the inverted cup getters are somehow typical for russian tubes. These seem similar with the ones I am waiting to try and I expect them to be delivered on Friday. I have big expectations that these will sound good. At the moment enjoying RCA 807 and I have also a pair of Sylvania 5933 (direct replacement) which sound good and bias the same. These 807 are a gem!


I own 2 pairs of Sylvania 5933 but haven't listened to them. Not sure why I haven't tried them out yet. Actually I do, been enjoying the other tubes I own too much! I think those Russian 807 tubes are very good, especially considering what they cost! 807 tubes are a great value overall, seems like even the cheap ones are really good. I run mine in single ended pentode mode but I've heard they are great in triode mode as well.


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## Isaacc7

OctavianH said:


> Some sellers are marketing them as Western Europe but the inverted cup getters are somehow typical for russian tubes. These seem similar with the ones I am waiting to try and I expect them to be delivered on Friday. I have big expectations that these will sound good. At the moment enjoying RCA 807 and I have also a pair of Sylvania 5933 (direct replacement) which sound good and bias the same. These 807 are a gem!


One other thing, the 6bg6 is an octal 807. So essentially a 6l6g with a top cap. The trick is that later versions of the tube had all sorts of more powerful guts stuffed into them. There are versions with Sylvania black plate 6l6gc guts and some with 7027 innards. They use a different adapter than the 807 of course.


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## OctavianH (Jan 6, 2022)

Isaacc7 said:


> I think those Russian 807 tubes are very good, especially considering what they cost! 807 tubes are a great value overall, seems like even the cheap ones are really good. I run mine in single ended pentode mode but I've heard they are great in triode mode as well.


Here these are triode strapped but they sound very good and your remarks match my expectations.



Isaacc7 said:


> One other thing, the 6bg6 is an octal 807. So essentially a 6l6g with a top cap.


I guess for now I'll stick to 807. In the future, who knows.

Later edit: I tried here 2 pairs of 6L6 and did not quite like them. I was expecting that 807 is close to 6L6 in sound but I think there is quite a big difference. Or maybe I have not tried the "right" 6L6. Anyway, price/performance ratio is much better on 807.


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## OctavianH

What do we have here? The russian 807.






I tried to make some pictures, first with the RCA 807 - RSD 807 (russian):





And some details:





These bias more or less the same as the RCA807 and Sylvania 5933, but as every russian lot of tubes I tried, tolerance is not great. So with russian tubes you have 2 options if you want a decently matched pair: buy more and pair them yourself or ask someone to measure these. In my case, I was able to make 2 decent pairs from 5 pieces and preferred to buy cheaper than to buy more expenssive and pay for matching. Anyway, these were around 10-15EUR/piece and with a little bit of research you can take them cheaper.





Now soundwise, these are a little bit more sterile and towards neutral than both RCA 807 and Sylvania 5933, but retain some of the 807 sound. I'll keep these more hours because are listenable. However, I doubt these will make me renounce on RCA ones which are better and also decently cheap. Anyway, everything is according to my expectations. I'll report later about these.


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## OctavianH (Jan 7, 2022)

A website I found by mistake in a Friday afternoon while searching for excuses to start my weekend earlier. I've seen some really nice stuff, so I will share it.
I have no idea if it is well known or not, I did not knew about it.

Glow in the Dark Audio

(Tubes / Amps / Opinons sections are quite nice)

Later edit:
In the amps section there is a part dedicated to Elekit TU-8200 and there are some 807/5933 remarks (here).


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## OctavianH

And because I read earlier about Sylvania 5933WA I could not resist to return to it.





This is like the story of the beauty and the beast, these 5933 are damn ugly but sound very good. I have a feeling Sylvania 807 is exactly the same, but I have here no Sylvania 807 so I have to deal with what I have. And these are quite nice, a level on top of the russians, more lifelike and euphonic. These are one of the best power tubes I tried on Eternity. However, I will keep close the russian counterparts because those are not so bad, and for the price are quite good. Their story has not been told yet, we just take a break for the next season.

I will make a bold statement but I cannot avoid it, I think about it for some time already: 807 and EL34 are my favourite outputs for Eternity and I have a feeling these are one of the best for several models from UltraSonic studios. This is only an assumption because I have not heard other model except this one, but still, my instinct tells me that because every review I read about other models points me to the same "house sound" (of course here I talk about modern models and not Odyssey or Telemachus, those are other recipe). This amplifier opened me infinite possibilities in a land far above what I was used to. Being able to use natively on output all these tubes like KT66/KT77/KT88/6L6/EL34 and with adapters 807/5933/EL3N and also on input natively 6J5/6C5/6N7/6SN7/6SL7 and with adapters 7N7/C3g/6F8G and many others besides those mentioned made me reach higher grounds. Also the feeling of manual bias, where you measure, you check, you have control helped me gain confidence and I have a feeling this type of bias provided me a more controlled sound, which in the past in my former amplifier with auto cathode bias was not possible. I remember that at that time I had moments when after some change the amplifier needed time to settle, or things did not sound as expected. Here that feeling is gone, you measure, you set, you wait but in the end works fine and it is rock solid. It is harder at the beginning but later you start to know the amplifier and "feel" if I can say like this what you have to do. Because I know my tubes very well I am not measuring all the time, just roll more or less voltage because I got the "feeling" of how much I have to add/substract to reach desired bias (Disclaimer: do not do this at home!). I start to think I do not want to go back to automatic bias.


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## SonicTrance

I'm very glad you're having so much fun with Eternity! This is what the tube rolling add-on was supposed to be!


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## OctavianH

SonicTrance said:


> I'm very glad you're having so much fun with Eternity! This is what the tube rolling add-on was supposed to be!


Honestly it is very fun and rewarding but I guess it is not for everyone. You need to take care and spend time and be patient. But if you are organizing yourself it is incredible fun and the experience and taste you get using these I have a feeling it will help also in the future if you will use future amps. Time will tell where I will be in 10 years from now on, at the moment, I am here with the tube rolling add-on.


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## OctavianH

Going on a classic path today. 6H8C + 5933. Not bad.





Ah yes, that dust. Damn, I need to clean Eternity a little bit later.


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## OctavianH

Some 6SL7 CV1985 with 5933. The RCA 807 is bolder sounding, does not match so good with some of the inputs, but these Sylvania 5933WA are quite good with almost everything you combine them with. Ugly but get the job done, very good outputs. And the 6SL7 goes well with planars, my D8000 love them.


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## OctavianH

And to close my evening in style, I could not smash better my principle of "no adapters, no top cap" than with 6F8G.





These 5933WA work nice with 6SN7 and equivalents and also 6SL7. Not bad. We need diversity.

And I found another blog to read:
http://truefi.blogspot.com/


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## OctavianH

And here I end my Sylvania 5933 journey. Mullard ECC31.





What I have learned today is that these 5933 (and most probably all 807 since I consider these similar) like a lot double triodes with a decently warm sound. Best results I had with Foton 6H8C or Mullard ECC31. I liked all combos I tried today but somehow these shine with warm full bodied inputs. A little bit surprising because I usually combine in contrast. Well, if you try to put these with a tube on the other side of the spectrum, well, they do not sound so good. EL3N was fine because they sound quite warm and forgiving in input on Eternity, but other more colder inputs did not made so well with these. This is a matter of synergy and most probably amp dependant, I have no idea. But what I have learned today is that I need to use these with decently warm inputs. No problem, we have such. Of course, these are very personal opinions, in the end, in this hobby all is personal.


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## OctavianH (Jan 12, 2022)

I've spent the last few days with the russian 807. Their sterile presentation, compared to the RCAs, can be easily compesated by a carefully chosen driver. So I tried this with Foton 6H8C ('55) and what I hear is very nice. These are detailed and clean sounding, they only miss that lifelike/natural sound the others provide. But for the price you pay, honestly these are a steal. Just put there a warmer and more euphonic input/driver and these will rock. I do not really feel the need to change this combo.





And since we started to discuss about 807 more and more Ebay listings appear. This is a funny one and I'll post a picture from it:





We have here GEC, Brimar and Zaerix branded tubes, but all are identical in construction with my russian 807. If you look on the GEC logo it states "made for" and on Brimar "foreign". So it seems these made the world tour. Mine are branded as RSD, identical with these. Langrex sells these as Ferranti here and here as Marconi. I've seen also some "RCA England" tubes here which are the same.

I'll continue with these more days, to see where this goes.


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## OctavianH

In July 1942 RCA was publishing the Guide for Transmitting Tubes (source here) calling the 807 "The Little Magician" (page 8). List price 2.5$.





80 years later my beer pint looks at them. Future is different than many imagined.


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## OctavianH

When Sunday gets closer you put your Sunday tubes. GEC KT66!






My D8000 with FAW Noir Hybrid cable are definitely the best headphones I ever had the chance to listen and the amount and quality of bass allows me to listen to a wider range of tubes and also to enjoy some poorly recorded records. Advantages of a warmer signature. KT66 sounds spectacular on Eternity in this combination, and this reminds me that the tube combo is just a link in the whole chain, headphones and every piece of it matters in the synergy. The good part is that D8000 remains a very technical headphone, in my humble opinion, even if it provides this generous bass I was mentioning. Nothing bloated, nothing blurry, all as it should be. Maybe a little bit more bass than I would normally listen to but this enhances a little bit the euphonic and organic sound. This planar does not sound like a planar, nor like a dynamic, for me it is in the middle of both worlds and the fact that it allows me enjoy KT66 is a strong plus. In the end Eternity, was built for it.


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## OctavianH

A topic about furniture. Yeap, from the SF department of audio affairs. But first let's look at this picture:





That's my Feliks Audio headphone stand, made from wood and around 3-4Kg. Yeap, it's heavy. Anyway, I am posting this because of a fun fact. Today I wanted to store my T1s which do not get too much attention because of the D8000s. Because the stand was useless I put it also to storage. And now comes the interesting part, D8000 started to sound a little bit different. Less bass, less punch and more airy. Well, I said, what happened. Of course, not a night and day difference, but audible. After some visual inspection, nothing moved, nothing changed, all good. And then I thought about vibration isolation, heavy wood and so on. My TT2 is on rubber feet on top of M Scaler and M Scaler on rubber feet on the desk. I remember when I put them like this I had the feeling both sounded better but I never spent time on this. Now back to our problem, I put back the stand and the bass and old sound was back. I said I am crazy, made a coffee. Repeated 5-6 times the exercise. Same feeling every time. Well, now we have an empty headphone stand on TT2. I know, sounds crazy, but before spending thousands on the most expensive tubes maybe check your backyard for a piece of wood. You might obtain something. LOL

PS. As I said, a subtle difference, but audible. If Feliks would knew what quantum technology they have in this stand, I could never have afforded it.


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## OctavianH (Jan 27, 2022)

There are things in life you are afraid to do. Because you might be dissapointed. The same feelings I have when I add something to the headphone line and I have to test it. Depending on the component type, I am more or less afraid, but headphones are always on the top of the list. D8000 was a brave addition and I had very good results with the normal listening sessions, but I never put them to test to some very special albums I consider to be mandatory for me. I usually delay such listening sessions, always feel I am tired, I do not want to take a decision and so on. But today it was a big day, the day I had to try D8000 with Black Sabbath first 8 albums. I always consider this a test which will make me take a final decision when evaluating a product.





And the answer was that Verite is better for this type of recording. D8000 has more details, speed and precision but on this type of album looses the real natural timbre of the Verite. Here we have a decently slow type of music where we do not need the separation or resolving skills of the D8000, and the more intimate and emotional sound of the Verite is taking the throne. I am sure I can compensate up to a point the signature, but we are sure that here Verite wins over D8000. It is not a night and day difference, both sound good but if we make a ranking we need to specify the winner. D8000 sounds a little bit drier compared to Verite. Of course, there are several album editions available and each one of them might add something, but overall this is my conclusion.

I will continue to investigate the D8000 in the realm of classic rock albums. In the meantime I guess these guys are interested in the result.





*Later edit:*
I fixed 90% of my problem by changing some inputs. The main problem here is not the D8000,which at first seems drier, it is in fact more transparent showing more from the recording and rest of the line. Verite adds a veil, their house sound, which makes jazz/classic rock older recordings sound better. But this house sound masks some imperfections of the record and also hides some nature of the tubes. D8000 does not add anything, showing you more from your chain. At first it seemed D8000 is inferior, but being more transparent makes rolling more effective. On the long term, D8000 will help me enjoy and tune more and make me use Eternity more efficient. So the short term looser might be a winner on long term. Of course, this can be an advantage if you have enough tubes to roll, otherwise a more forgiving headphone might be the better choice.


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## OctavianH (Jan 28, 2022)

After I understood that basically D8000 is not drier, but more transparent and shows more from the tubes, recording and production than Verite it was no problem for me to fix the missing magic of the old rock recordings. I was on a wrong path in the past assuming that what I was hearing was the headphone signature, D8000 does not quite have a signature, and this is a very good thing if you have a very flexible amplifier like Eternity. Because with such a headphone you can make almost everything you want. Do not understand me wrong, I am not trying to minimize Verite's qualities. Verite is a magic headphone, somehow tuned for jazz or classic rock. On timbre you cannot beat it. Verite makes bands like Black Sabbath sound phenomenal with almost every tubes you throw on it and this is very good. But it does that having a special house sound which many including me are loving it. Switching to D8000 you start to hear faults in production, effects of remix, sound might loose some coherence and so on. But this happens only on poorer recordings, because it is more unforgiving. That transparency costs you, you hear also what you would not want to. Anyway, there is always a solution and for me it was KT66. KT66 is an incredible tube, especially for guitars, but what it does on Eternity is that it adds a little bit of "veil" and compensates D8000. On Verite these were a little bit too fuzzy for me because their effect was on top of the "house sound", but on D8000 and these kind of recordings they are just perfect.





Black Sabbath sounds phenomenal in this combination, with KT66 and some detailed 6SL7 like this CV1985. Maybe it is a good time to go to Led Zeppelin first 4 albums. I've not listened to them since pandemic started.

*Later edit:*
I like a lot this. A very nice post. My only remark is that while I fully agree with what he says, that energy of D8000 is mandatory for rock music. He listens to electronic music and bass reproduction is more important to him. I will not hide my personal opinion that Empyrean is a headphone which makes the experience on a solid state amplifier more tube like. I always had that feeling. That emotion, lifelike and all they describe is for me what I hear on a tube amp and this is why I started this path. Of course, I might be wrong, but I am more and more convinced that a flexible amplifier like Eternity and a transparent and energetic headphone like D8000 is my perfect match. Time will tell. The difference of owning Empyrean and a solid state amp and Eternity and D8000 is that in the first case you have a very nice flavour while on the second case you have 100 flavours if you know well your tubes. And Eternity being hybrid is fast, detailed and does not carry the "classic design" flaws. So it has best of both worlds for me. On top of that D8000 sounds quite technical and analytical while never making me tired. Or at least until now, but here the tube amp might have a word to say.


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## OctavianH

One thing which started to happen since I have started to use D8000 for my listening sessions is a more often need to change or adjust the tube combo. I praised this headphone for its transparency and also considered it very suitable for such an amplifier, because it shows more from the nature of the chain and, therefore, the nature of the tubes. And in the end this is what we do here, we change tubes and exploit the potential of this flexible amplifier. But there is a disadvantage, it is more unforgiving. And if you have many ways to adjust, you'll want that more often. Today I wanted to change my tubes 3 times. I had a feeling that one combo matched perfectly one album, but was not as good on the other. With the Verite this was not happening, all was more or less the same. It is true that having more room for rolling, you can tune everything closer to what you want, but this will also require more effort. It is good? It is bad? Each one has to decide based on its own preferences.





I switched from RCA 807 to Sylvania 5933WA black plates. Both are good, bias the same, but sound different enough to make sense owning each. I cannot say which one are the best, honestly both are great sounding on this amplifier and are a strong recommendation from my side, alongside Tesla EL34, and it seems I am not the only one enjoying them. I read today what I could find about these and reached here.

My journey on the path of 807 is nearly its end. I have no wish to continue or invest, I have a few pairs of decently measuring RCAs and 2 pairs of Sylvania 5933WA black plates. I like them a lot and I will keep these close to me for a long time, they worth every penny. I also have a few russian G-807 which are not far and I have no problem to use and enjoy. In a short period of time these reached position 2 in my preferences for output tubes on this amplifier and I think I can say these will be a good choice for other UltraSonic builds, because I doubt Oblivion or Citadel are far away on signature. And speaking about other amplifiers I have to admit I thought for a while about what would make sense to be my next tube amplifier. But these are just thoughts because I cannot say I am missing something at the moment. Anyway, if I would want a complementary amplifier that would be a Citadel with 807 on outputs and 6SL7 on inputs. I expect that one would use 4 outputs and 2 inputs, as the currently available models, and this was the reason I wanted at least 2 pairs from RCA 807 or Sylvania 5933. If I would go with the 5-pin base of these I would be very limited on tube rolling, but I doubt I want to roll also on that one. I can go again for my octal socket no top cap philosophy of "simplicity" and that would allow a quad of EL34 or KT66. But I always like to have complementary products, so maybe a simple Citadel without any grid adjustments will be enough. Why 6SL7? Because these are more clean and energetic with D8000, and sounded good also with Dynamic headphones. I tried several 6SN7/6F8G/7N7 and in the end realized I use more 6SL7 on Eternity. Even 6J5 are not so often used. But this is just free thinking on a Sunday evening. Honestly 2 flexible amps are too much for me, 2 amps in general are too much for me because I have in this one 100 flavours to choose from.


----------



## OctavianH

The GEC E3375 burn in started. These are far from sounding decent, but they have good pedigree. Honestly these remind me more about KT77 than EL38 but there is too early to say something. I'll let these at least 100 hours and then try to compare. In the meantime, I read this. He's right, these bias like EL38, around -10V grid on Eternity at 200V/20mA.


----------



## triod750

Looks like too much of GEC there. I would change the input tubes since I've read several times that GEC with GEC might be too much of a good thing. But what do I know?
Your continuing journey never loses interest. Happy travel!


----------



## triod750

http://www.r-type.org/exhib/acl0353.htm Here I found the explanation I have been looking for:
The GEC label to the right - the GEC brand was used for professional valves whereas Marconi and Osram were the consumer brands of M-OV.​This thanks to you, Octavian!! So just keep on experimenting and educating us...


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## OctavianH (Jan 31, 2022)

You're right, I do not like for example GEC KT66 with GEC L63 clear glass.
And this is exactly what I have done (I'm using the double triode in the center). But I've changed that to this one:





This one has to be a Tung Sol 6SU7GTY. And yeap, this is a nice tube. I'll have to learn more about these 6SU7/6188 tubes because I have to admit, I do not know almost anything. I am not educating anyone, at least I try to educate myself, let's hope one day I'll have the level to understand things better because I feel I am far away from that.

*PS:* The E3375 is not my discovery, I have to thank @leftside because he has done a remark in the Beam Tetrode thread here. This reminded me that at the times I was reading about GEC KT66 I've got upon a very interesting thread where a former GEC employee was discussing with another person some of the company history and the E3375 was mentioned. At that time I made a small note on a personal document "to be searched for, E3375" but later forgot about it. The reason for the note was that I had some Mullard EL38 in the Elise years and liked it, so any GEC equivalent was something I would normally like to try. I had no idea at those time that the construction of these is somehow similar with KT77.


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## OctavianH

I'll dig into these 6SU7GTY. In the meantime some pictures, because this is exactly what I am missing when reading about these to understand more.


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## OctavianH

And now we test the most important quality one must have in this hobby: patience.


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## whirlwind

OctavianH said:


> After I understood that basically D8000 is not drier, but more transparent and shows more from the tubes, recording and production than Verite it was no problem for me to fix the missing magic of the old rock recordings. I was on a wrong path in the past assuming that what I was hearing was the headphone signature, D8000 does not quite have a signature, and this is a very good thing if you have a very flexible amplifier like Eternity. Because with such a headphone you can make almost everything you want. Do not understand me wrong, I am not trying to minimize Verite's qualities. Verite is a magic headphone, somehow tuned for jazz or classic rock. On timbre you cannot beat it. Verite makes bands like Black Sabbath sound phenomenal with almost every tubes you throw on it and this is very good. But it does that having a special house sound which many including me are loving it. Switching to D8000 you start to hear faults in production, effects of remix, sound might loose some coherence and so on. But this happens only on poorer recordings, because it is more unforgiving. That transparency costs you, you hear also what you would not want to. Anyway, there is always a solution and for me it was KT66. KT66 is an incredible tube, especially for guitars, but what it does on Eternity is that it adds a little bit of "veil" and compensates D8000. On Verite these were a little bit too fuzzy for me because their effect was on top of the "house sound", but on D8000 and these kind of recordings they are just perfect.
> 
> 
> 
> ...



Awhile back I went through my Led Zeppelin library, which is pretty much everything.  I saw them in 1977, The Presence Tour.

I had not listened to them in sometime and what wonderful couple of weeks that was.  

Man I loved these guys.   Have fun with Zep


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## OctavianH

whirlwind said:


> Awhile back I went through my Led Zeppelin library, which is pretty much everything.  I saw them in 1977, The Presence Tour.


I was not even born in '77. But some bands have no age. Luckily for us there are a lot of newcomers sounding quite good. For example The Vintage Caravan.


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## OctavianH (Feb 4, 2022)

I've spent some time with my "6SL7 division". Luckily for me, Eternity needs only one of these, compared with my previous amplifier, so finding one at a decent price was not a problem. I do not have many, but I like a lot the ones I have. I find them clean and more energetic sounding than the 6SN7. I know, not a very scientific explanation. It might be a consequence of the design of the amplifier, I have no idea. But I like these and I'll add a few more to my collection.





A nice article to read about them here.


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## Tonyaudio

OctavianH said:


> I have a pair of original Genalex Gold Lion KT77, the one from which they made the reissue, and it is a very warm and forgiving tube, on Elise. Warmer than KT88 or KT66.
> From what I have read, it seems EL34 might be the same, but I never had the chance to try those. I will do it on Eternity.


I have a quad of original Genalex Gold Lion KT77's also and switch between them and some original Mullard EL34's. Like them both!!


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## OctavianH

You are lucky to have a quad, these are rare nowadays. And the problem is that you like them, I like them and everyone likes them. So nobody is selling and the sellers are asking crazy prices. I've seen a quad of GEC KT77 on Ebay for 1200 EUR. Incredible. It was in Italy, the tube prices on Ebay at sellers from Italy are usualy double than normal but in the end what is normal in this hobby? I was lucky to buy 2 pairs in the past, one GEC and one Genalex and they will never leave my collection. I was also lucky to secure a few GEC E3375 which are, in my opinion, sounding similar. These are the best I was able to use on my amplifier and also better than every EL34 I have tried. But it is in the end a matter of synergy, taste and so on. So do not expect to obtain the same synergy on every amplifier. What is happening at the moment on D8000 with GEC E3375 and Siemens C3g is incredible.






I am currently listening to the latest Ashes of Ares album and maybe it has a production level which puts this combo and the D8000 in advantage. But for example on this track I will put a link below, the separation and level of detail is astounding. This song puts accent to a very technical drummer, and here the texture and organic bass of D8000 comes into play. You can almost feel every beat and the sound is so natural that you almost feel you are in the recording studio. But things do not stop at the drum level, the bass does not cover the other instruments, everything D8000 renders is perfectly coherent even if the songs contains a lot of intense passages. Vocals, guitars, drums sound perfect. It is a very precise sound, you hear everything which is happening with accuracy but you do not feel you are tired, nothing is exagerated, sibilant or sterile. This is what I was searching for when I started into tube amps and here I am after a long road.



I tried the D8000 also with my solid state amplifier, the integrated one from TT2, but honestly it could not match Eternity. I do not feel with Eternity any loss of detail, speed or anything, I can say both are at the same level but Eternity adds an additional layer of emotion. If TT2 makes everything sound precise, tight and clean, Eternity makes it clean, tight and lively. And this is why I will never be able to remain faithful to a solid state amplifier. The same thing I am trying to describe here I have already read on the Empyrean/Elite threads. This is why my opinion is that the magic of Empyrean and Elite is the ability to sound on a solid state amplifier in the same way as some headphones on a tube amplifier. But yeap, in that case you have a flavour, in my case you have 100. I strongly advise any D8000 owner before selling these headphones to try them on tubes.


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## Tonyaudio

OctavianH said:


> You are lucky to have a quad, these are rare nowadays. And the problem is that you like them, I like them and everyone likes them. So nobody is selling and the sellers are asking crazy prices. I've seen a quad of GEC KT77 on Ebay for 1200 EUR. Incredible. It was in Italy, the tube prices on Ebay at sellers from Italy are usualy double than normal but in the end what is normal in this hobby? I was lucky to buy 2 pairs in the past, one GEC and one Genalex and they will never leave my collection. I was also lucky to secure a few GEC E3375 which are, in my opinion, sounding similar. These are the best I was able to use on my amplifier and also better than every EL34 I have tried. But it is in the end a matter of synergy, taste and so on. So do not expect to obtain the same synergy on every amplifier. What is happening at the moment on D8000 with GEC E3375 and Siemens C3g is incredible.
> 
> 
> 
> ...



I know what you mean as I can not bring myself to sell most of my tube collection also. I keep telling myself that I will buy another piece of gear to use them in again and maybe I will. Others I will use occasionally then put back on the shelf. It feels good knowing that these pieces of history have been preserved for the future.


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## OctavianH

I am playing a little bit with 6SL7. I think there is a lot of potential in Eternity using these and we are lucky we can still find some at very good prices.





And as usual, there is always a nice story to read at the morning coffee.


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## OctavianH (Feb 11, 2022)

Switching between several 6SL7 is a pleasure, all of them are sounding nice on this amplifier. But in the end I usually return to the same "usual suspects": CV1985 or ECC35.





Recently a third model became one of my favourites: Tung Sol 6SU7GTY. With these 3 on input and GEC E3375, RCA 807 or Tesla/Mullard EL34 I can live forever.
I guess these are my favourites at the moment, but I am keeping close Sylvania 5933, GEC KT66 and on input Fivre 6N7G or GEC L63 clear glass. A special mention deserves also the Sylvania 6CA7. All these are excellent and I was lucky to discover them.


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## OctavianH (Feb 14, 2022)

If the bass sounds right here, I usually think it is fine and this is a good test for me for my D8000 Pro headphones. D8000 is also close here to check.


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## OctavianH (Feb 14, 2022)

Testing my D8000 Pro with Black Sabbath. There is no Black Sabbath without Bill Ward. Never.



Later edit: 13th of February was first album's 52 anniversary. I have forgot about this, but somehow returned to them exactly in these days. Nice.


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## OctavianH (Feb 14, 2022)

Soon 1 year since I have received the amplifier. But last few days were for me a kind of rediscovery of its potential, and this was caused by D8000 Pro. How much a well designed headphone can improve your listening experience and overall satisfaction in this hobby.


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## OctavianH (Feb 16, 2022)

What to do with 20 EUR in 2022? Well, you can buy a Marshall 6SL7WGT which is manufactured by Sylvania. Most probably if it was branded Sylvania it would have been more expensive, but who cares. This tube sounds excellent and is perfectly balanced. Even the prints and everything looks as new after around 55 years since it was manufactured.










I could not find a 6SL7 which does not sound good on Eternity and all are different enough to make sense owning. I have around 5-6 and I can recognize each of them when used on the amplifier. And most probably these sound nice on all UltraSonic modern design amplifiers which I think are not that different.

Next step, Tung Sol 6SU7, I guess it is impossible to find a pair which looks in the same way here, but I expect all these sound identical (the one in the right is the "6188" one). These are the OCD guy nightmare, nothing similar, even if these should be the same tube. Well, we'll find out about this in the next weeks.


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## Isaacc7

OctavianH said:


> What to do with 20 EUR in 2022? Well, you can buy a Marshall 6SL7WGT which is manufactured by Sylvania. Most probably if it was branded Sylvania it would have been more expensive, but who cares. This tube sounds excellent and is perfectly balanced. Even the prints and everything looks as new after around 55 years since it was manufactured.
> 
> 
> 
> ...


Yeah, the brown base Sylvania 6sl7 are great tubes. I slightly prefer the bottom getter cylindrical plate JAN 6sl7 Sylvania but I made sure to get a handful of these brown base ones as well. Has anyone seen a 12sl7 version?


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## OctavianH

I was late to the 6SL7 party but better late than never. I have no idea why I never tried these on my previous amplifier. At least now I need singles and not pairs. The black base older versions from 50s might be a little bit better but I prefer to save the money. I am fine with these 60s brown base.


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## OctavianH

No discrimination here at Tube Rolling pub. After so many nice brown base 6SL7 we'll take into dance the black base ones.





The one I am the most interested in is the Fivre 6SL7GT and the reason is that I have a brown base one which looks identically except the base colour. That one sounds very nice but it is microphonic. This means when you start the amp you hear some crackling while tube starts to draw some current. If you touch it or if you play with volume when the knob reaches the lower stopper again a small sound. Anyway, usable, nice sounding, but it has this problem. And a similar problem I have with a pair of Fivre 6C5G brown base. Identical issues. So I've start to think it might be related to some common construction of these. I also have a pair of black base Fivre 6N7G which do not have this problem. So the 1M $ question is: Is the Fivre 6SL7GT black base similar? Or not? As Hamlet was saying "To be or not to be, microphonic?". I'll check this today in the evening.


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## UntilThen

OctavianH said:


> Recently a third model became one of my favourites: Tung Sol 6SU7GTY.



I'm swinging with one now.  Haven't bought a single tube for a while.


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## OctavianH (Feb 18, 2022)

UntilThen said:


> I'm swinging with one now.  Haven't bought a single tube for a while.


You are a man of taste. That one is a nice one. Too nice to be true almost.

I bought a few 6SL7, just to have some flavours I remembered I liked in the past while using 6SN7. My 6SN7 collection decreased a lot, a part of the money were reinvested in a few 6SL7 but the results are above expectations. And 6SU7 are, I guess, one of the best ever built. Also my 6AS7 collection is gone, I have one pair of TS 5998 and that's it. For collection purposes, nothing more. Maybe I'll use my tinkering skills to build a lamp of it oneday to display it near my audio line as a piece of history.

Later edit: The one you have I guess is the famous 6188. But I am not convinced there is any sonic differences between this one and 6SU7 or 6SL7. I think there are only selected tubes with matched sections. More a matter of quality check than electrical design. I'll study a little bit more about these.


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## OctavianH

Ok, curiosity killed the cat. I've tried the Fivre 6SL7GT black base and the issue I was mentioning before is 70% solved. Meaning I heard it, but almost undiscernable. And wow, how these sound is incredible. I've always put Fivre after british tubes for this sweet nice tone with a lot of detail. I love it.





I tried to find out something about the date codes but it has nothing on it, or it was deleted, except the stamp. And on the stamp I see 8/5. I guess that's the only clue I have. I doubt the markings on the stamp match production date, they have to be a later date, but can be a clue about a range of years. I need to dig on these. Most probably by searching for similar pictures, with similar stamp type and construction and see if others have identified a date code on them, then consider these manufactured in the same period. In the end, what matters is that I like them.





And another discovery. RCA 6SL7GT. These remind me of RCA VT-231 but have that energy I love in these 6SL7. Some call it slam, others in different way, it is most probably the sound of 6SL7 mixed with the house sound of RCA.





On another note, I was not so impressed about Tung Sol VT-229 black glass or Ken-Rad VT-229 (first 2 from left from here) but this is most probably because I like this sweetened british sound. So a matter of taste more than a matter of the tube itself. Ken-Rad was as expected, great bass but a slight loss in detail, that one reminds me of Ken-Rad VT-231 I had in the past. Conclusion is, after trying 6-7 types of 6SL7, that I like them in the same way I liked the 6SN7 counterparts. This matching my theory that if you start with 6SN7 and discover what you like, switching to other type and knowing a little bit about each manufacturer's signature you know directly which one you'll like.


----------



## UntilThen

OctavianH said:


> The one you have I guess is the famous 6188. But I am not convinced there is any sonic differences between this one and 6SU7 or 6SL7.



Well you know more about these tubes than I do. I don't even know the significance of 6188 but it is.


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## OctavianH

UntilThen said:


> Well you know more about these tubes than I do. I don't even know the significance of 6188 but it is.


As far as I know Tung Sol 6188 and Tung Sol 6SU7GTY/WGT/whatever are all 6SL7GT tubes. But they are selected for low microphonics, sections matched, they are rugged versions. So this is why I expect that soundwise are similar, but maybe these were the "premium grade" ones selected from the normal production, the ruggedized versions being intended for use in specific appliances. I have no idea exactly. Anyway, that's a great tube and I expect it sounds wonderful in Odyssey.

Here are my 3 pieces and the one from right is similar with yours:


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## UntilThen

I like the black glass one in the middle.


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## OctavianH

UntilThen said:


> I like the black glass one in the middle.


If you want one I can tell you who might sell you a pair. I'll PM you.


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## UntilThen

OctavianH said:


> If you want one I can tell you who might sell you a pair. I'll PM you.



Thanks but my next purchase will be a ECC35.


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## OctavianH

Since I've listened all day to different 6SL7 I wanted also to measure health of several pieces. I wanted to do this in the past but I reached a point when I was not convinced my procedure is the right one. I will explain. Well, different tube testers measure in different conditions the tube and assume 100% health at different emission levels. For example my Duovac has the following specs for 6SL7:





All simple, you just have to make some connections, place the tube and measure one by one triode the plate current.
But now comes the problem, if I look in the datasheet I see the following:





And we see that my tester manual says to measure at Va=300V/Vg=-2A and 100% is 3.2mA while the datasheet says Va=250V/Vg=-2 and 100% is 2.3mA.
Other testers like the Roetest which is, as far as I know, the best one available on the market provides a report where the health is related to the datasheet values.





If I look at the graphs, well the Roetest and also the datasheet tell the same thing:





You see in red the 2.3mA at 250V/-2V. At 300V/-2V we should have 3.4mA and not 3.2mA as my tube tester manual tells me. So this is why I have no idea exactly which of the both measurement conditions is the right one for 6SL7. But I've done it in both ways for 2 tubes:





Brimar 6SL7 CV1985 was bought NOS from Langrex recently, as we see, measures around 80% according to the tester manual and around 75% according to datasheet.
Marshall 6SL7 is just a Sylvania 6SL7GT I choose randomly just to see how it behaves (I put some pictures with it recently). So now the 1M $ question is: *how do we measure correctly 6SL7 health? *@SonicTrance I know you have a tube tester, at which test conditions you measure 100% a 6SL7? I expect it is a mistake in the tables of my tube manual.

*PS.* This is not happening for all tube types, some of the testing conditions match datasheet (for example I measured 5998 without problems with dataset from tube manufacturer)


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## SonicTrance

OctavianH said:


> how do we measure correctly 6SL7 health?


You should measure like your tester is telling you. Not all testers will test at the same operating point. As for the 0.2mA difference I wouldn't worry about it. Remember that tubes are high tolerance devices and the curves were hand drawn. Maybe if you look at a different 6sl7 datasheet and try to find the exact same operating point it fails. Close is close enough


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## OctavianH

I've contacted the tube tester manufacturer and he confimed me that my theory is fine, and the 0.2mA difference was because he used curves not so precise (or different) than the ones from the datasheet I have checked. So in the future I'll measure according to datasheet and double check with what a Roetest will measure (most probably always what the datasheet specifies). A small step for science but a huge step for me in understanding how things work. Now the weekend can start.


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## SonicTrance

OctavianH said:


> Now the weekend can start.


Where's the beer?


----------



## OctavianH

SonicTrance said:


> Where's the beer?


Guilty. I'll have soon a beer, in the meantime congrats for the sense of observation. When Tube Rolling ends, Beer Rolling starts. As always.


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## OctavianH (Feb 19, 2022)

It had to be done. Now time for some Black Sabbath.

Later edit:

This guy knows:


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## SonicTrance

OctavianH said:


> It had to be done. Now time for some Black Sabbath.
> 
> Later edit:
> 
> This guy knows:


Haha! Awesome!


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## UntilThen

My ciders 😉


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## jonathan c

SonicTrance said:


> Where's the beer?


Maybe you can build for @OctavianH a headphone amplifier that features output stage pintodes…


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## OctavianH

jonathan c said:


> Maybe you can build for @OctavianH a headphone amplifier that features output stage pintodes…


And input stage ciders. Then I'll drink it, or drink to it... LOL


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## OctavianH (Feb 20, 2022)

One leftover of 2021 was the Telefunken EL156. I failed to use these in Eternity and the root cause seemed to be a damaged tube. However, all the tubes were looking decently on my tube tester. Of course, not new, but usable and in good shape. Today I wanted to take over again and after hours of extensive measuring and checking I was able to find that one of the tubes was from time to time acting strangely on the tester. Curent was jumping to 341mA without reason, sometimes G2 (which is at +14V in my case while measuring the pentode strapped as triode, according to my tube tester manual) was going to 0. This happened only for one of the tubes and needed a lot of patience to reproduce. Hell knows what is exactly the cause, what is more important is that the other 3 were fine, and the remaining problem was only to pair 2 of the remaining ones. Said and done.





After I decided which pair I will use, of course, again a lot of tests and checks and so on. I was a little bit afraid of these and wanted to exclude anything which might damage the amplifier. During this process 2 long coffees needed to part away with us, so you can understand the effort. So the big moment arrived, headphones disconnected, volume set to 0, measurements in place, all steps double checked.





In the end I was able to use these in the amplifier and everything worked as expected. Damn, I was afraid of these.





The Telefunken EL156 datasheet contains some graphs. What interest us in Eternity seems to be this one:





From this graph and considering what I learned yesterday related health measurements, normal bias for these on Eternity should be around -14.5V for a 100% measuring tube. Well, mine goes for -12.5V so the tubes are around 85% health. Most probably more than I will ever need.

Now, I guess, what is interesting for others is the sound. This tube is a power horse:





I don't really understand why we would need a 50W pentode in a headphone amp but well, I have not experienced as much as others with hungry headphones or as many amps. This is my third tube amp and for the house sound of Tomas, "clean, wide and fast" I would prefer some british sweetness or warmer output tubes like EL34. But this is me. So my expectations, based on what I know about Telefunken sound from EL34, which goes to neutral/dry but very detailed and precise, well, my expectations were moderate.





The first 2 hours I paired these with what I had on inputs from my previous listening sessions, more exactly Sylvania 6SL7WGT. My focus was on the currents and monitoring of these small monsters. But after things settled and all seemed fine, I realized that the Sylvania 6SL7WGT was not a good pair for my taste. Being airy, clean and somehow thin sounding was somehow accentuating the dryness and sterile sound of the Telefunken EL156. It was, indeed, a very fast and tight bass, solid state like precision, extremely muscular and powerful sounding, somehow reminding me of the Tung Sol KT150. But here the sound is more refined, more detail and less "synthethic" sounding. A kind of NOS KT150 sound, or at least how someone would imgagine it (KT150 is a newly designed tube so you cannot find any NOS but if you try to imagine how those would sound, based on other reissue vs NOS comparisons, this would be the sound).
So my next try was to warm these and add some british sweetness to them. So the first choice would be Mullard ECC35 or maybe some GEC L63. In the end I went for the ECC35 and things went more in my direction of preference. The sterile sound went to a level I can accept. The punch and speed remained there, and the overall signature was the same. Anyway, the Telefunken house sound is still there and you can like it or not. In my case, being sold to the UK sound I still felt I was missing something. Of course, my impressions are amplifier related, here the main signature is chosen with the outputs and inputs only add some "condiment" to it. In other desigs these might sound different.
In conclusion, these go towards KT88/KT150 type of sound, but they retain that Telefunken "audiophile" sound. Definitely these are good, for the ones who like the previously mentioned tubes, but for my musical preferences where the guitar plays an important role, GEC KT77 remains the undisputed king. Sweeter, more rounded, more natural for the electric guitar. These might be the sound of power. GEC might be the sound of the 70s UK rock albums. Everyone perceives this differently, everyone likes something else. I will continue to listen to understand more, in the end I put a lot of effort to reach this point and I hope I've helped others to know more about these.

A nice article I've found during today's tests was this one. A good read for people wanting to dig more in the Telefunken EL156 land.

Longer post than expected, I wanted to cover a little bit the sound but also some technical impediments I had on the road. This was for me an important milestone. That's it.


----------



## OctavianH

The return of the mighty RCA 807.






And for the sake of some tube pron, 2 Brimar 6SL7 which look identical to me, except the base. The one in the right is the one on the amp above.


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## UntilThen

I've not use my 807 for a while. On my GEC KT66 now.


----------



## OctavianH

These RCA 807 are indeed beautiful and the sound is excellent. Top class tube.


----------



## UntilThen

OctavianH said:


> These RCA 807 are indeed beautiful and the sound is excellent. Top class tube.



I think so too when I first heard it. For the price, they are value for money. Has the DNA of 6L6.


----------



## OctavianH

Morning coffee with a view. A good way to start a day of work.


----------



## OctavianH

OctavianH said:


> Here are my 3 pieces and the one from right is similar with yours:


I made today some tests with these. Well, all sound different even if I was not expecting this. The grey glass is the most "creamy", while the one in the left the most dry/analytical. The 6188 is somehow in the middle, I need more time with it. What it matters, these 3 have their own flavour. There is no better or worse, all are good in their own way.


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## triod750

Of course they sound different - their mica shape is different and everybody knows that the sound lives in the mica .
You'd better shape up!


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## OctavianH

triod750 said:


> Of course they sound different - their mica shape is different and everybody knows that the sound lives in the mica .
> You'd better shape up!


Contrary to my expectation, which was that all 3 are sounding identical, today I heard quite big differences between the clear/grey glass. Now ok, both clear glass might be close, and I'll try this again another day, but...


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## OctavianH (Feb 24, 2022)

The story of Red Riding Hood? I have to admit I never really apreciated these even if many praise them.









But who knows, they'll find their purpose sometime. Much overpriced for what they offer in my opinion. However. they are, indeed, beautiful.


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## mordy

OctavianH said:


> The story of Red Riding Hood? I have to admit I never really apreciated these even if many praise them.
> 
> 
> 
> ...


Based on what I read, the red base RCA 5692 is a severely over rated tube. If memory serves me right, there was a dealer sitting on a large stock of the red base 5692 tubes, and he started an ad campaign to present them as supertubes with the concomitant high prices.
My theory is that the average person cannot distinguish too much between different tubes, and if there is an easily identifiable characteristic, it helps the efforts to hype it up by unscrupulous sellers. Everybody knows that black glass tubes are better sounding than clear glass, brown base is better than black base, and curved base GEC tubes sound better than straight base etc etc. And red base? Wow!


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## OctavianH

mordy said:


> Based on what I read, the red base RCA 5692 is a severely over rated tube. If memory serves me right, there was a dealer sitting on a large stock of the red base 5692 tubes, and he started an ad campaign to present them as supertubes with the concomitant high prices.
> My theory is that the average person cannot distinguish too much between different tubes, and if there is an easily identifiable characteristic, it helps the efforts to hype it up by unscrupulous sellers. Everybody knows that black glass tubes are better sounding than clear glass, brown base is better than black base, and curved base GEC tubes sound better than straight base etc etc. And red base? Wow!


These small red base tubes sound for me soulless. It is a kind of "low distortion" sound with rolled off highs which tells me nothing. Dull, unexciting. Many praise them for long life time (10000 hours) but in both amps I've tried these are running quite hot. Most probably because of the small glass where everything fits tight? Anyway both 5692 and 5691 got quite hot on both Elise and Eternity. I do not know exactly the operating point of Elise but on Eternity I run 5692 at 180V/3mA this leading me to a plate dissipation of  0.72W, which is seriously below 1.75W from the datasheet. For 5691 it would be 0.54W below 1W from the datasheet. So I do not think I force these in any way. I'll measure some temps next time I will use them. Maybe the rugedized nature of these makes them need very long burn in time? I have no idea because I doubt I'll ever have enough patience for them.

Regarding black and grey glass tubes, I never considered them superior, even if these are older than clear glass, but I've observed that usually these coated tubes are warmer and more "euphonic" than the clear glass counterparts. However, there are several cases where I prefer clear glass tubes because they sound cleaner and clearer to me. A good example is GEC KT66 grey glass vs GEC KT66 clear glass. I had the chance to listen to both a lot and all the time went for the newer version.


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## OctavianH

RCA 6SL7GT. A good pair for RCA 807.


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## OctavianH

A nice BW one. RCA 807 with Mullard ECC31. Most probably from 1960 when I was listening to Eternity.


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## OctavianH (Feb 28, 2022)

We live unfortunate times when War Pigs become reality. Sad times. Let's hope we will get better.


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## OctavianH

My relationship with the Fivre tubes is special. While I appreciate the house sound and always find them a good pair to many of my output tubes, often something happens and I decide to put them back in the box for a while. A few weeks ago I was complaining about them being microphonic, today one 6SL7GT almost blew the fuse on Eternity. I always watch currents raise to both stages, this is a proof for me that all goes well. Everytime one stage starts to draw very fast current or the meter goes backwards from a point I know something is wrong. It happened with EL156 before finding the problematic tube, which was not operating properly, it happened with some EL38 some months ago and it happened again today. After inserting the Fivre 6SL7GT in the input socket and turned on the amplifier, the needle started to move normally until let's say 10mA, then the RCAs 807 started to draw much faster current and in the end stabilized at 20mA where they should be. I thought it's only that but in a few seconds the needle jumped to maximum. I've stopped immediately the amplifier and thought I had to change output protection fuses and so on. I was lucky. Nothing happened and the amp works perfectly with ECC35. But my Fivre 6SL7 went to the box and I'll do some extensive measurements with it. In the meantime, the only Fivres allowed to remain near were 6N7G and 6C5G. Eternity is a strong amplifier, I am surprised how reliable it is after several small incidents.





While I never read anything about Fivre as being of a lesser quality I cannot ignore some incidents I had: microphonic tubes, one dead at arrival from the shop (might be the shop in this case) and now some crippling and problems with one of my 6SL7. I might be not very lucky with this brand, I do not try to blame them, just mention that in my case I'll be very careful with these, even if I like a lot how they sound.

I spent the last days with RCA 807 and rolled a lot of inputs, I am preparing to make some comparisons between several 807 brands and see where this will go. For me RCA 807 remains a challenge, a tube which sounds incredible but needs a little bit of sweetness to be perfect. This is a different situation than what I was usually doing. Using GEC or Mullard on output I was able to pair them with RCA/Ken-Rad/Tung-Sol easily. But now, these outputs are forcing me to find new recipes. Even in this situation, I will not renounce on these, because the bass and overall signature is very close to what I call endgame.


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## OctavianH

Going a little bit to british territory with a Mullard 807 branded as Philips QE06/50.






But the date codes are Mullard, Blackburn, October 1966 (xk1 B6J4):





And yes, now we have an 807 with a british sound, exactly what I was looking for. The structure of 807 with the flavour of Mullard. Damn, this is incredible.





But there is another episode to this story, and that one next week.


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## SonicTrance

Very nice tubes you got there!


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## OctavianH

SonicTrance said:


> Very nice tubes you got there!


Somebody has to love the unloved tubes, while all others love only 300B or EL156. Unloved tubes are the most precious to me.


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## Isaacc7

OctavianH said:


> Somebody has to love the unloved tubes, while all others love only 300B or EL156. Unloved tubes are the most precious to me.


I'm the same. Love my 14n7 and 7c5 tubes! Part of me wants to have an amp built that allows me to use 2e26, 6146, or other "boat anchor" tubes for no other reason than to make use of them lol. Doesn't make any sense but I love the idea of using tubes that others pass by. Think I'll be ok once I get my amp that allows me to use 6v or 12v output tubes. 12v6, 14c5, 12aq5, gu50, and maybe even 12av5 tubes oh my!


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## OctavianH (Mar 4, 2022)

Isaacc7 said:


> I'm the same. Love my 14n7 and 7c5 tubes! Part of me wants to have an amp built that allows me to use 2e26, 6146, or other "boat anchor" tubes for no other reason than to make use of them lol. Doesn't make any sense but I love the idea of using tubes that others pass by. Think I'll be ok once I get my amp that allows me to use 6v or 12v output tubes. 12v6, 14c5, 12aq5, gu50, and maybe even 12av5 tubes oh my!


The purpose of a tube rolling thread is experimentation. We need to try stuff, otherwise we would not be here. Of course, in limits of time and budget and, let's hope, common sense. It is not possible to try everything in the world. But you can focus and research for some of them and then have some fun. There is no glory in buying the most expensive amplifier and the most expensive tube pair and then say "It sounds good". LOL. It's like buying a Ferrari and then say "I have a good car". I guess everybody knows that. I was reading yesterday about Western Electric 91E, at 15K $ (they offer some preorder 10% around 13.5K $). I expect it sounds good, it has to. LCD screen on front, this will be a strong selling point in 2022. The next level is to provide software updates to the amp and new themes monthly.

I think 807 lost a lot because of the socket (5 pin) and 300V max screen voltage. Many, I guess, preferred to use something else in their designs. But what I hear here is on the same league with the celebrities, at least the ones I've tried, while paying a fraction. Of course, personal opinion, nobody has to believe me and might not be a general consensus for every amplifier. In the end these very expensive types everyone praises now were not all designed for audio and were at the same price level when all started. This is why I put all tubes on the same potential level and never ignore a forgotten one.

I have one more trick in my hat related to 807, this will happen next week if those tubes will light. I bought last 2 sets of 807 used, untested and in a not so good condition. From 4 x Mullard 807 one was dead, one was 25% and the last two were NOS 100% or more. At the price I've paid I am happy, but there was a risk. I've done the same with what I'll present next week. I have 3 pieces, if 2 work fine and are decently electrically paired to be usable, we'll have some fun, if not, that's it.

PS. I wanted to try also 6BG6 but availability in Europe is limited, ordering from US might involve higher shipping + VAT and I'd need a new pair of adapters, so I'll stick with 807 and let others try it.

PS2. What amp you want to get?


----------



## OctavianH

I've spoken a lot about 6SL7 recently. Mostly about Mullard ECC35, Brimar CV1985 or Tung Sol 6SU7GTY. I've said something also about Sylvania 6SL7WGT.
But I forgot to mention one special tube:





The RCA 6SL7GT grey glass. I have 2 pieces, one with date code KV (which if I'm not wrong is '58) and 59-48. Both look and sound identical. Why I am mentioning it? Well, after the ones I've mentioned before, this one is also special. I find it relaxing, airy and in the middle between technicality and euphony. It somehow reminds me of RCA VT-231 grey glass, which I still have somewhere in a box. I liked it from the first time I tried it, with RCA 807 and now, with Mullard 807 it is the same, a very good pairing.

What is important to me is that all these 6SL7 versions are different enough to make a difference, different enough to provide a different experience and compensate something else. Soon Eternity will have 1 year and I'll have to write again my impressions and I am not a good writer. But I think the most important Eternity era findings were EL34, 807 and 6SL7. Luckily to me these were some of the cheapest tubes I've bought. In the past, while deciding to upgrade from my former amplifier, I've read a lot about "amplifiers designed to sound best with cheap tubes". I was reluctant. Elise, and most probably Euforia, scales a lot with expensive tubes, and you just feel it sounds better when using unicorns. I loved Tung Sol 5998, GEC KT66 and also Western Electric 421A. I liked a lot GEC 6AS7G even if they were a little bit too polite for my musical taste. But my wallet did not love them. I've started my Eternity journey with the same mindset that expensive is better, because this is why it is expensive in the end. But I had along the way a few surprises. One of them was Tesla EL34, another was RCA 807. It is also true that I was blown away by GEC KT77 which is not cheap, but the difference between these is not night and day. All are different (even if KT77 is a kind of premium EL34 for me soundwise) and all need a proper pairing to shine. The last surprise was Sylvania 6SL7GT and I think the root cause here is related more to the new design of UltraSonic studios. There are many tube parameters we do not understand or ignore, but which might have an impact on the final design, for example rp. Uneducated users, like myself, speak about gain, heater current or check a simple curve to understand how to set the bias for properly operating the amplifier. Those other parameters do not "ring a bell" for us and therefore we ignore them. Maybe the trick of using cheaper tubes and obtaining a good sound is to compensate or mitigate effects of other tube parameters. Maybe the trick is the gyrator or the mosfets in my amplifier. The tube are doing only what they do best, so a cheap 20 EUR piece is able to provide me the same sonic benefit like a unicorn. Or maybe just a cleaner power supply or, why not, something else. Let's hope during time I'll understand more and find also the scientific explanation of my experimental findings.

Weekend is coming, it is Friday Beerday. I need a beer.


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## Isaacc7

OctavianH said:


> The purpose of a tube rolling thread is experimentation. We need to try stuff, otherwise we would not be here. Of course, in limits of time and budget and, let's hope, common sense. It is not possible to try everything in the world. But you can focus and research for some of them and then have some fun. There is no glory in buying the most expensive amplifier and the most expensive tube pair and then say "It sounds good". LOL. It's like buying a Ferrari and then say "I have a good car". I guess everybody knows that. I was reading yesterday about Western Electric 91E, at 15K $ (they offer some preorder 10% around 13.5K $). I expect it sounds good, it has to. LCD screen on front, this will be a strong selling point in 2022. The next level is to provide software updates to the amp and new themes monthly.
> 
> I think 807 lost a lot because of the socket (5 pin) and 300V max screen voltage. Many, I guess, preferred to use something else in their designs. But what I hear here is on the same league with the celebrities, at least the ones I've tried, while paying a fraction. Of course, personal opinion, nobody has to believe me and might not be a general consensus for every amplifier. In the end these very expensive types everyone praises now were not all designed for audio and were at the same price level when all started. This is why I put all tubes on the same potential level and never ignore a forgotten one.
> 
> ...


I've been talking to @SonicTrance about an amp. Not sure what it will be called. I'm aiming for a push pull amp, fully balanced so no phase splitter and xlr inputs. He assures me that I can get what I want even though that is quite a bit lol. switchable 6v/12v for both input and output tubes, adjustable B+ and manual bias so I can use anything from 6f6 to el38, triode and ultra linear output etc. I'm hoping to use transformers from Monolithic Magnetics. I really only listen to speakers but will also get a balanced output for headphones. I'm in the saving process right now, that amp will consume the entirety of my hifi budget for the year!


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## OctavianH (Mar 5, 2022)

Isaacc7 said:


> He assures me that I can get what I want even though that is quite a bit lol. switchable 6v/12v for both input and output tubes, adjustable B+ and manual bias so I can use anything from 6f6 to el38, triode and ultra linear output etc.


Sounds very interesting and for me it looks like a kind of Citadel with some tube rolling stuff on top. Will you go for octal sockets and use all others via adapters? I'm not sure if you follow the other thread but I've wrote something about a similar amp here. Not with 12.6/6.3V switch, but in rest I guess there are some similarities. I doubt that I will ever order it because I am pleased about mine, but I am *VERY* interested in what you plan there.


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## Isaacc7

OctavianH said:


> Sounds very interesting and for me it looks like a kind of Citadel with some tube rolling stuff on top. Will you go for octal sockets and use all others via adapters? I'm not sure if you follow the other thread but I've wrote something about a similar amp here. Not with 12.6/6.3V switch, but in rest I guess there are some similarities. I doubt that I will ever order it because I am pleased about mine, but I am *VERY* interested in what you plan there.


Yes, octal sockets with adapters. My idea which this amp is that it be a kind of love letter to tube rolling and push pull amplifiers. I don’t need much power, I figure it will top out around 30 watts per channel running el38 tubes in ultra linear and go down to around 5 or 6 using 6aq5 or even 6k6 in triode. I love tubes and I love making them sing in different combinations and using oddball ones. My intent is to use a wide variety of input tubes including the 2c50, 12sx7, 6bx7, 6bl7, 6c8g, 6f8g, 7n7, 14n7, 14af7, 6/12sl7 and the good old fashioned 6/12sn7. I’ll even try 12j5 with suitable adapters.  I’m already sitting on a ton of these from different manufacturers, all American though. The European stuff has just gotten too expensive unless I can luck into some 12v versions. 

I have a bunch of output tubes in mind. I have a good supply of el38, 6ar6, 14c5, 6v6, 6aq5, 807/5933, 6bg6, and 12av5. The 12av5 supposedly has a resemblance to the 2a3 when run in triode and I have always been interested in trying them. I think I would like to try a variety of 12v6 tubes and gu50 as well. I’ve been told that the amp can have a variable voltage and biasing points to allow all of these different tubes it be used. Not sure that isn’t a more common feature if it is doable. Maybe other companies don’t want to risk their customers blowing things up lol. 

My current amplifier is a Dennis Had KT88 Firebottle. It is a SEP amp and is quite lovely. It also allows me to use just about any pentode or tetrode as long as the screen grid can take 260 volts or higher. The plate voltage is varied by changing rectifier tubes. The input tube can be just about any double triode other than the 6080 family. I’ve had a blast mixing and matching various combos of input and output tubes. Oh, and my preamp (a Supratek Cabernet) adds another level of tube rolling on top of that. I love music but the hobby part of audio is exploring vacuum tubes and what they can do.  It’ll take me at least a few more months of saving before I’m ready to get in the queue. I will admit to day dreaming about though, it’s my dream amp.


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## OctavianH

Many tube types you mention are unknown to me. However, 6AR6 is something I would like to try and the reason is the article here. I agree with him on several tube types I tried and I have a feeling 6AR6 would be a good addition to my collection. I will keep an eye on several offers and maybe I'll buy a pair.


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## Isaacc7

They really are nice, especially for the price People have said that they compare well to the original Tungsol 5881 or at least that the plate structure looks the same. I wouldn’t know, I’m too cheap to buy those lol. Even with the price of adapters figured in the 6ar6 are bargains. If you like the 6l6 family sound you’ll like the 6ar6 Let me know if you have questions about any of the other tubes I mentioned, always happy to geek out about tubes 


OctavianH said:


> Many tube types you mention are unknown to me. However, 6AR6 is something I would like to try and the reason is the article here. I agree with him on several tube types I tried and I have a feeling 6AR6 would be a good addition to my collection. I will keep an eye on several offers and maybe I'll buy a pair


.


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## OctavianH (Mar 8, 2022)

If we end an important chapter, the 807, we need to end it in style. And the best way is with GEC ATS25. I knew very little about this tube, for me it was a mistery, but I was able to find 3 pieces used and untested at a very competitive price. I took the risk and all worked fine, unlike the Mullards where 2/4 were dead. This is the risk you take when you search in forgotten corridors for tubes nobody cares about or has the possibility to test. My curiosity about them raised when reading here.





I was not able to see any markings or date codes on these except "ATS 25 N". But I tried to make some decent pictures of the areas I consider important.





Are these GEC ATS25? A premium version of 807? They seem to be, one of them was branded "Cossor - British Made". But this is not telling me enough. Soundwise these sound british, a little bit richer than the Mullards but not far away. Or it might be Placebo, because this is what I expect them to sound... Time will tell.

Of course, these were awaken from a long sleep, need time, but I can say from the beginning that these do not sound like the RCAs I tried quite a lot recently and are closer to the Mullards.





And this is the end of the 807 chapter. A terrible journey, with dead tubes, with plans for other amplifiers, with a lot of reading on several forums. Now comes the time to settle and take each pair one by one and decypher. The hunt is over, now we need to spend time and understand.

As a preliminary conclusion, I can say that RCA 807, Sylvania 5933, Mullard 807 or GEC ATS25 are all great tubes. One of the best I was able to use on this amplifier. All of these are eletrical matching 807 specification, bias the same, work with the same adapters, are more or less in  the same "line" of sound. But they are also very different. All 4 sound different enough to make sense owning a pair, and also to make sense using an amplifier built for them. For bass and tightness I would go for RCA. For a more airier and wider sound for Sylvania. The british versions, all sound cleaner and more delicate, less bass but sweeter on mids. I am awful at descriptions but when I think about the Mullards I always think somehow at Mullard EL38. I cannot say why, they have something in common as flavour. When I listen to thes ATS25 I think about the inputs from the picture, the GEC L63 clear glass I have near the RCA 6SL7GT grey glass. Also maybe these go a little bit towards GEC KT66 but with more bass and authority. So, if you know those maybe you'll have an idea where each of these stands. I will keep close all 4 types and play with inputs to see how far I can come to what I consider for me end game. I will not be hard to pair these, all sound good. It is more a matter of taste or rest of the line to choose a winner. In my specific case, well, I always liked british sound.


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## OctavianH (Mar 9, 2022)

First low light listening session with ATS25 and I've seen that both tubes have a blue glow. Well, the one on the right a little bit more than the other. But both work well and measure well, nothing spectacular. I've read here a little bit, let's hope I should not be worried.





Later edit:

It's actually very beautiful. GEC glow is always the best.


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## triod750

This is an indication that you should listen to blues and not your prefered music. But you are a big guy and make your own decisions. Just ignore it!


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## OctavianH

triod750 said:


> This is an indication that you should listen to blues and not your prefered music. But you are a big guy and make your own decisions. Just ignore it!


Well, maybe at least Blue Oyster Cult.


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## OctavianH (Mar 11, 2022)

After spending time with 6SL7 and 6J5 it came the time to show some love to 6N7.






Later edit:

The superstar of today: RCA 6N7GT clear glass.





And some reading.


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## OctavianH

I had a lot of fun with the RCA 6N7GT clear glass from the picture above combined with GEC ATS25. Warm and decenly relaxed, it also provides a quite powerful signature and brings back something from bass and tightness of the RCA 807. These GEC ATS25 are more romantic, rich sounding, but lack a little bit of the bass and forwardness of the RCA. Using this input you quite combine the signatures of GEC and RCA and obtain a nice mixture. If you want to go more for speed, energy and tighter and punchier bass, all you have to do is to put an RCA 6SL7GT VT-229. This one:





With this tube as input the drummer was in the center, bass was incredible fast, tight and textured. A very energetic sound. But for a Friday evening it was a little bit too much. So I have returned to GEC L63 grey glass, one of the tubes I wanted to use in Eternity since the early days of planning.





The sound you obtain with this GEC combo is wide, rich and emotional. Vocals, piano and acoustic guitar sound incredible. In my case there is a problem on the tone of the electric guitar which is a little bit dry, but if you do not listen to rock music you do not care about this and this combo might be your endgame. And if you listen to rock you can live with it in slower and more atmospheric songs. And if you want more, well you can go to the 6N7 or 6SL7.

After almost one year of Eternity I realised that things are not so complicated when deciding what to combine. On outputs the clear winners for me are EL34 and 807. These are the best, KT66 and KT88 just cannot bring me the same level of enjoyment. And the reason might be that this detailed and less distorted sound Eternity is providing needs a little bit of emotion and warmness, and these 2 tube types (alongside 5933, KT77 or 6CA7 which derive from them) are basically doing exactly that. On inputs, the clear winners are 6SL7 but this is subjective, I prefer fast and intense music where their energy is useful. But there are times when 6J5 or 6N7 which are more relaxed have an important role. 6SN7 remains on the last position in my preferences.

Friday Beerday. Now I need a beer.


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## OctavianH (Mar 12, 2022)

I am thinking why I prefer 6SL7 > 6N7 > 6J5 > 6SN7 and one thing might be the gain. 70 > 35 > 20 >= 20. In the case of the last 2, I find 6J5 cleaner and better sounding than 6SN7. This is a common preference, everyone usually prefers single triodes instead of dual triodes and 6J5 is a half of 6SN7. Or at least this is the conclusion when reading the dedicated reference thread. Another reason might be the house sound because it is almost impossible to find british dual triodes at a decent price, while 6J5 GEC or Brimar are still up to some point "affordable". Most probably GEC B65 sounds good but I'll never afford it. LOL. 6J5 is the only single triode in these 4 types. So, gain is the answer?





Later edit:

I found a website which explains at my level of understanding. Or at least I hope so. Ah, they explain gyrators and tube rolling. I have no idea if I'll understand more, but at least I'll drink for sure more coffee. And this guy is located in "Wauwatosa, Wisconsin, USA (suburb of Milwaukee).  Wauwatosa is the Potawatomi word for firefly." Damn, it seems besides electronics, geography was not my strong point in high school, I am able to read those words almost at the same level I understand tube parameters.


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## OctavianH

I could not change for a few days the GEC ATS25 + RCA 6N7GT  combo. I guess that says something.


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## Isaacc7

I have a few RCA clear glass 6sn7. I find them to be a bit wild and woolly in my amp. Might be a good combo with the 12j5gt Sylvania tubes I’ve put into my preamp. They make the system open and clear but maybe I need a little wildness to balance everything out? I am enjoying the RCA 6bx7 in the amp right now. Not all amps can use them due to their heater requirements but it is a powerful sounding tube.


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## triod750

OctavianH said:


> I could not change for a few days the GEC ATS25 + RCA 6N7GT  combo. I guess that says something.


Octavian, don't be so lazy - you have to make an effort. How hard can it be to change some tubes?


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## triod750

Isaacc7 said:


> I have a few RCA clear glass 6sn7. I find them to be a bit wild and woolly in my amp. Might be a good combo with the 12j5gt Sylvania tubes I’ve put into my preamp. They make the system open and clear but maybe I need a little wildness to balance everything out? I am enjoying the RCA 6bx7 in the amp right now. Not all amps can use them due to their heater requirements but it is a powerful sounding tube.


Are you using the 6BX7 as input or output tubes? With what do you combine them?


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## Isaacc7

My amp (Dennis Had Inspire KT88 Firebottle) allows me to use 6bx7, 6sn7, or 6sl7 for the input tube. The output tubes are run in single ended pentode. I can use just about any pentode/tetrode that can handle 260v on its screen. Plate voltage varies depending on which rectifier I use. I've used a ton of different output tubes... 6f6, 6v6, 807, 6ar6, 7185a, kt66, el34, el38, and soon I will try 6aq5 and 6bg6ga. The amp is a tube roller's dream! 

My preamp is a Suprtek Cabernet. I had a switch added that allows me to switch between 6sn7/12sn7. I just got some adapters that allows me to use a pair of *j5 tubes instead of the normal *sn7. So between my preamp and power amp I can really change the sound of my system with tube changes. 

Right now I am listening to some live Clifford Brown. My preamp is using Sylvania 12j5gt tubes. I've switched the input on the amp to the same clear glass RCA 6sn7 and I've got some Firenti labeled, Russian 807 as the output tubes. The RCA added back some warmth and lower midrange wallop to the equation. I'll let my ear get used to it over a few nights and see if I'll let it stay that way. I tend to switch things up every week or so because I've got more tubes to try. 

Next up on the tube rolling front I've got some JAN Tungsol 12j5gt for my preamp. I've got some cool stuff coming for the amp. I'm expecting some Tungsol 6c8g tubes this week. Later on I'll get a big shipment of 6aq5 tubes made by Mullard, Telefunken, and some French brand I can't remember. As you can imagine, swapping one set of tubes can cause a ripple effect across the gear. It's a lot of fun!


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## OctavianH

Isaacc7 said:


> Right now I am listening to some live Clifford Brown. My preamp is using Sylvania 12j5gt tubes. I've switched the input on the amp to the same clear glass RCA 6sn7 and I've got some Firenti labeled, Russian 807 as the output tubes. The RCA added back some warmth and lower midrange wallop to the equation. I'll let my ear get used to it over a few nights and see if I'll let it stay that way. I tend to switch things up every week or so because I've got more tubes to try.


These russian 807 are not bad at all. They sound a little bit dull compared to RCA but that can be compensated with some Sylvania 6SL7 and you are good to go. In my case I prefer warmer inputs for them and 6N7 is a very good candidate. I'll have to turn my attention again towards them in the future. One thing I really appreciate at the 807 is the fact that it was produced by many manufacturers in Europe and US and with a simple pair of adapters you can obtain 4-5 flavours which are different enough to make sense owning. Because all bias the same, you can build a simple amp with fixed bias and just roll 4-5 pairs and have a lot of fun. If in the past I was chaotically trying tubes, lately I start to think about the tube type and also about the manufacturer and then decide if I'll go into that direction. For me the tube type is the shape of sound while the manufacturer is the colour of it. So a tube type with the proper shape (bass/mids/highs/gain/others) needs to have also enough options of flavour (GEC/Mullard/RCA/others) to become of interest. Applying this kind of thinking I postpone, for example, 6AR6 or EL39 because using those I might not obtain all the results I am expecting.

My next chapter will have novals in the spotlights, but higher gain ones since I've started to prefer them in my current configuration (D8000 Pro + Eternity). So 12AT7/12AX7 most probably. But I postpone this since I am really having fun with 6N7 and 6SL7 at the moment. The pleasure is the road and not the destination. Afterwards I'll do what?


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## OctavianH (Mar 18, 2022)

Friday Beerday! When is a better moment to make some rolling? I wanted today to put the GEC KT77 in the amp again to check them against my newer discoveries. But they did not wanted to compete today, made some awful noise in the amp and I have decided to leave them in the box. That's it, some tubes, if are stored for a longer period of time, become grumpy and need some time to be usable again. This is not the only pair which caused me such issues. This reminds me about an article where someone claimed that if you store a tube for 1-2 months you already need to re-burn it and wait a few days for any assessment. Well, hell knows, for sure this is not a GEC KT77 day. Nor a good day for GEC KT77 vs GEC E3375 comparison, which is, in fact, the reason I wanted to use these.

But, since I got here, I decided to go again to EL34 path and Mullard EL34 xf2 is always a good companion. This time with RCA 6SL7GT clear glass. Excellent bass, detail and dynamics. One combo which brings something to the table. EL34 remains in top 3 in my output preference list for Eternity. And Mullard and Tesla are the ones I like the most.





With EL34 and 807 I do not miss anything on this amplifier. KT88 or KT66, even if they are very good, miss something. KT88 is for me a little bit sterile while KT66 lacks some bass and authority. Of course, personal preferences. In KT88 case I never listened to the famous GEC KT88, I have only new production, but that goes out of my budget and I am fully convinced it cannot beat for me these already mentioned.


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## OctavianH

And the picture in good light.


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## OctavianH

Many consider a tube amp expensive. Others, like me, tend to buy and try more than needed. But in fact, the tube amp is my biggest saving strategy. I have 100 amps in one and I can play with them and I never get bored. If something is missing there will always be a combo to compensate. Of course, you get something and you loose something, there is no perfect combo, no perfect headphone or equipment. But as long it is flexible you are happy. I was on a long term run to tweak my headphone line but now I am happy. The D8000 (pro or non-pro) are excellent for transparency and are very responsive to equalizers. And after all, these tube amps are a kind of hardware equalizers (many will hate me for saying this). So a good Saturday means beer, means GEC ATS25 and GEC E3375. Currently listening to the latest Dark Funeral album with Mullard EL34. Brilliant!


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## OctavianH

If you wonder if tube rolling makes any sense after you found the perfect tuning the answer is yes. There is in the end no perfect tuning, we listen to what we think is the sound they wanted, but we were never in the studio with them, we do not hear like them and do not share the same brain. And they are the band we love. I always said I am a huge Black Sabbath fan, but this does not matter, music is music and everyone perceives differently. The reason I am mentioning them is that today I've listened to the first album on Mullard EL34 xf2 after a long period of GEC ATS25. It is not better, it is different. I know every bit of that album, I cannot say one combo beats it. It is true that I am a fan of the GEC sound as many are on these forums, but Mullard EL34 xf2 nails it in a different way. EL34 and 807 are my winners, personally chosen, on this specific amplifier which is built in 2 pieces, but I can say each roll of these 2 types of tubes makes me feel the album differently. Roll people, buy flexible amplifiers, sustain the community of rollers, we are able to listen to music in many different ways and this makes sense. This is the reason I will never buy a fixed bias amplifier, I loose all these "faces" of music. I want to change, to have control, to roll and to obtain what I dream of.


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## OctavianH

Late evening with EL34. These are indeed incredible on mids. But in the end I miss my ATS25. Do not understand me wrong, EL34 are killer on a fast detailed amp like this one. What Tomas makes is magic using his new design on tube amps. But if we speak about winners, for me ATS25 and 807 in general is a better tube in terms of detail retrieval or synergy. It might be the trick of GEC vs Mullard, but I have no GEC EL34 to compare. Mullard EL34 xf2 is my best bet (after Tesla) but still I prefer 807.


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## OctavianH

10 days without any change. No rolling, no need to change, just music. Will this be the end of the tube rolling? I doubt. But it is for sure an important milestone for my understanding of this amplifier. A similar point was reached by me several years ago with Elise when using GEC KT66 with GE 7581A. I used that, I guess, over one year and it dethroned for me the Tung Sol 5998 with Psvane CV181T2. Of course, quite different both combos to compare 1:1.





The last rolling weekend brought underwhelming results, because the reassessment of EL34 made me switch back, in the end, to ATS25. And this is the proof that my brain is not able to properly assess the incremental upgrades. I switched from EL34 to 807, to explore several manufacturers. After american ones I was able to obtain 2 european made pairs. I liked these a little bit more and, in the end, I stopped at GEC ATS25. Every change seemed small, more a matter of taste, but returning several steps back showed me how much the signature changed. EL34 and 807 will remain my winners and favourite tubes. I doubt something can dethrone these, but ATS25 is for me the king and the nature of its superiority is confirmed more and more after hundreds of hours when you listen to more and more from your catalogue, tracks you forgot or never considered important which now have something special, something you never heard before. This is the real value of a special combo, the ability to let you smile after hundreds of hours when you think you have heard everything.

What next? Well, it remains the noval chapter. The small tubes. But I will not explore too many, I picked already a few types and I'll try 2-3 types of each. And I might do one more interesting thing, but about this later, when we will have tubes, adapters and some nice pictures. There is no hurry, pleasure is the road not the destination.


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## OctavianH

And the incredible GEC ATS25 blue glow. Damn, I love this.


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## Krassi

Thanks for this lovely thread with all those detailed infos about the perfect 807 tube!
i was really looking for exactly this since i was lucky to get my hands on a great 807/6sl7 Tube amp and was looking for some awesome tubes for this!

I have got a pair of new horn speakers loaded with vintage Coral drivers (BK 202 with Coral 10L-60, Fostex H425 with Coral M-100 and Coral H-70)
And was looking for something that makes them shine. 

So i shot me 5x valvo QE06/50 tubes on the german-bay for the start (two smoked glass could be mullards) together with a nice nos 6SL7WGT SYLVANIA.
But of course tube rolling will be a mandatory for this new tube amp  !

Since 807 are not so boutique prized as 300b it makes it lis ess bank braking to try some more.

So i stumbled on your description of the GEC ATS25 wich seems to be what i really really want to try!
I also followed your link to michael and lets see what he can offer.

i really cant wait to get my hands on this new tube amp and hope to share some insights about 807 tubes.

Great stuff keep up your work and enjoy the music!


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## OctavianH (Mar 31, 2022)

Krassi said:


> Thanks for this lovely thread with all those detailed infos about the perfect 807 tube!


There is another great resource where I put some pictures to show construction of different 807 and equivalents here. Take a look maybe you will find something useful. I was not able to find enough information, I tried here to show them. I have 2 types of RCA 807, slightly different but not enough to picture there, so I put only the older one. Soundwise, identical, at least to me.


Krassi said:


> i was really looking for exactly this since i was lucky to get my hands on a great 807/6sl7 Tube amp and was looking for some awesome tubes


Can you tell us more about this great amplifier? Can we see it somewhere?


Krassi said:


> i really cant wait to get my hands on this new tube amp and hope to share some insights about 807 tubes.


Please do that, I am very happy someone else is enjoying the 807 with 6SL7.

*Later edit:*
Regarding Valvo, these usually rebrand Mullards or even russian tubes. For example here these look like my RSD branded russian 807. Not bad at all, but ATS25 will blow you away. Instead of ordering russian ones at 55 EUR I'll definitely go for RCA 807 which has deeper bass and sounds fuller. Even the highs are better, but it is not so sweet as the european counterparts. Show us some picture with your smoked glass ones. I do not have those.


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## Krassi (Mar 31, 2022)

Hi!

Thanks for all the Infos!

Here is a picture from the 807 tubes. I should get them next week since they come from germany.
Really a bargain for 39 bucks all together and tested good.




Yesterday i did some more doomscrolling with google and found some more 

-1x NOS RCA 6SL7GT smoky glass cheap from Croatia
-2x unlabeled NOS RCA 807 tubes for 19 bucks!


Well the Tube amp is still a mystery for me but its on its way from Poland and should arrive next week.
Regarding that Amp.. well i was really interested in a 807 amp after not being able to get a ultra amazing one from a guy from cologne (in the neighborhood).
That started my interest in 807 and i wanted to find someone who can build me one.

But suddenly i stumbled on this kleinanzeigen offer from poland after my daily hifishark, kleinanzeigen, bay search cycle 
"boom headshot".. 380bucks for a very simple but great crafted amp with 2x 807 and 1x 6sl7... i was really amazed since its such a simple design with a minimum number of tubes in a great crafted case.

So my belly told me "go for it and lets buy this!"  ... the person that build it seems to be an old guy with lots of knowledge about tube amps and after some wonky comunication with german to polish translation i got some infos about like 6 wats per channel and 8 ohms.

I have no clue what transformatiors are used but i guess those are not cheap chinese ones. Well no hashimoto, tango, hammond or similar but he told me it has no humming and sounds great.

Well with just 3 tubes it should be direct as hell 







I already have a nice super simple super compact custom amp that a guy from germany built for me.
it uses cheap russian video tubes and can do anything from XLR in/Out, MiniXLR in, RCA in, Headphone jack and speakers! In a case that is half of a paper! I wanted it for my AKG K340 in the first place and speaker output was "just an extra" 

And because i use this one for speakers only at the moment i have a tube amp only for my headphones.
It was a bijou tube amp prototype from the same guy that build an amp to drive the AKG-K340 to the mars and back ))

This thing can still go XLR in/out and RCA in and blast the crap out of my K-340 with 800ohm!
Its totally linear from zero to 100%!!

Holy sht since i never tried tube rolling this could be also interesting since it uses 4 tubes.
i Actually dondt even have a clue what tubes it uses !  i have a spare set for both amps since the guy really knew what he built and what tubes to use.

The black one is the headphone amp and the white one drives my speakers with 4 wats.. i was still to lazy to put another mahagoni wood knob on this one and still have a skweaking crap plastic knob still on it )


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## OctavianH

Krassi said:


> Hi!
> 
> Thanks for all the Infos!
> 
> ...


Very interesting. I doubt those are Mullards but might be similar with these. The ones on the right I guess are RCA. We will see when you receive them and maybe take a better look on them. Let us know what do you think of each pair 

Regarding the amps I have no idea, but I am very glad that I find more and more about 807 and others who might enjoy them as much as me.


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## Magol79

@OctavianH 



I just got these as my first pair of 807s. Do you have experience with Brimars?


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## OctavianH (Apr 1, 2022)

Magol79 said:


> @OctavianH
> 
> I just got these as my first pair of 807s. Do you have experience with Brimars?


Ah, so you bought them.  I was expecting this  I have no Brimar here and I was watching them. Nope, you are the pioneer, let us know what you think.
I guess you will like these, on Euforia these should sound nice, if Euforia is how I imagine it to be.

PS1. I doubt you can go wrong with 807, but if you do, sell those to me.

PS2. I doubt all these manufacturers produced them, I think some of them rebranded. Here I found a picture of a different one with "Brimar" printed on the base which looks quite different:





I guess we need to investigate more in this area. Yours look close, but no identical with my RCA.


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## OctavianH

I was saying a few days ago that I have several pairs of RCA (or at least labelled) 807. I made some decent pictures of 2 different ones to show.














As you can see, bought have slight differences. I wonder what "MBA" stands for under the 807 square. On british tubes (GEC and Brimar) I've seen "foreign" mentioned and those were tubes rebranded. I think this is the direction we have to investigate, to see exactly what types are available, who made them and who rebranded them.


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## hpamdr

Long long time since no post...
After some months of test and listening Eternity and comparison with SS, Euphoria, and MoodWright KWA-150se with magnepan for main system..
I have selected some combos which i like a lot depending of music session... (The music types drives generally different sound engineers ways of working..)


For solo piano, organ music and large symphonic ensemble my choice goes to GU50 as output tubes and single NR73 in input... The GU50 need long burning times to loss the dry but after many listening hours it is keeping dynamic on steroid ... Crystal clear sound, precise, dynamic all that could make a SS lover agree that Tube amps are ultra-precise (Thx to Tomas !)

For jazz, pop and small ensemble EL39 or EL12sp and dual NR73 or (Viseaux) 6N7G gives great amplification factor and works with all headphone adding a bit of boost in low and medium... If i had to keep only one combo flavor, this is the one I like with everything (Music, Headphone, DAC)

For electric pop, acid jazz, trip hop ..... I like a lot EL34, 6P7S, (still EL39) as output and EL11, EL3N 6M5 or 6SL7 as input with HeedPhone. This add some euphonic and darker tone which make tube sound with a specific flavor that no SS amp can compete !

For very small ensemble with female voices, i like a lot EL32 or 6V6 as output and single 6BQ7A or rca VT-94 with T1 or HD800s this gives some romantic sound...

I still have many tubes combo to test. I finally stopped to get new tubes  and just enjoy music a lot. 
I currently think that Eternity is one of the best audiophile purchase i did in the last 10 years but if i did not put my feet with first 500 bucks Elise, my path could have been totally different...


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## Krassi

Well i really love to search like crazy once you find something interesting.
Starting point was the new set of big speakers and the weird idea "lets look out for a new tube amp that can drive them to mars and back" 

Since i buy lots of stuff from yahoo Japan auctions you directly got totally blown away by those tons of sick vintage tube amps that are on auction all the time.
So you see lots of 300b and 2A3 and other weird stuff with freaking expensive Sansui Output transformers and lots of weird stuff. 

And since a tube amp builder that i asked also directly wanted to build something with 807 i thought "maybe those are really good!" 

I never thought about rolling tubes before because i was happy with the sound of my amps.
But with those really ok priced vintage 807 its really nice to instantly get lots of stuff to try without the risk of spending 200+++ bucks for chinese boutique stuff.

with a set of 3x different 807 and 3x different 6sl7 i should be able to try out lots of combinations! 
And as you mentioned you got one Amp and can customize it to fit the mood or music with just changing the tubes!

I also hope they glow blue ! would be some nice moody acid lightning.


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## OctavianH

hpamdr said:


> I currently think that Eternity is one of the best audiophile purchase i did in the last 10 years but if i did not put my feet with first 500 bucks Elise, my path could have been totally different...


This is a very strong statement which I think describes a lot your experience. Eternity is also one of my best purchases, alongside Final D8000 Pro and JCAT usb cards.


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## OctavianH

Friday Beerday, a good moment for a small change. I have decided to return, for a while, to GEC KT66 and see how these sound with the RCA 6N7G. I never had the chance to try this before. Let's see where this goes.


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## OctavianH (Apr 1, 2022)

The previous combo was good, KT66 on this amp benefits from a warmer driver and this is what I did not had at the time I played with them in the beginning of last year. This gave me confidence to try more, so a natural choice for me was the Tung Sol 6SU7GTY grey glass. In my limited experience with grey glass tubes I always find them a little bit warmer and more euphonic than the clear glass counterparts. And yeap, good catch. Even if you already have your favourite combos it is always a good practice to revisit some tubes and try to pair them with something you have not tried at that time. You might have a surprise.





I will not hide that I will go back to KT88 just to see how these behave with 6SL7. I never tried that. Unfortunately I do not have a pair of GEC KT88 and I do not plan to invest in one. So I might try the 2 pairs I have here, a Shuguang Black Treasure and a Psvane one.


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## hpamdr

Just a remark about chasing 807 tube, keep also your mind opened to try a Russian tube "6p7s" you can get several tubes and do the best match yourself.




I got some from an Ukrainian vendor, he is specialized in Russian military electronic ( capacitor (like inside some amplifier), knob, rotary switches, .... tubes).
Eternity seems to work quite well with this as output tube, amplification factor is very good and i like those with rock and electronic music...


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## OctavianH

hpamdr said:


> Just a remark about chasing 807 tube, keep also your mind opened to try a Russian tube "6p7s" you can get several tubes and do the best match yourself.


The 6P7S is the equivalent of the 6BG6 and I wanted to go this path but unfortunately these are not so easy to find cheap in Europe. There are 2 tube types I have in mind but never got to try 6BG6 (including the russian counterpart) and 6AR6. In the end I went for 807 and I am at the moment considering it my favourite output type. Since these are quite cheap and you can easily find in Europe 2-3 different manufacturers (including russian G-807 which sounds very good for the price), it was a good decision. Now, the 1M$ question is how is 6BG6 sounding compared with 807 on Eternity? Amplification factor is for both 8, heater Voltage and current the same (6.3V/0.9A) so... similar electrical specs, more or less?


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## hpamdr (Apr 2, 2022)

OctavianH said:


> The 6P7S is the equivalent of the 6BG6 and I wanted to go this path but unfortunately these are not so easy to find cheap in Europe. There are 2 tube types I have in mind but never got to try 6BG6 (including the russian counterpart) and 6AR6. In the end I went for 807 and I am at the moment considering it my favourite output type. Since these are quite cheap and you can easily find in Europe 2-3 different manufacturers (including russian G-807 which sounds very good for the price), it was a good decision. Now, the 1M$ question is how is 6BG6 sounding compared with 807 on Eternity? Amplification factor is for both 8, heater Voltage and current the same (6.3V/0.9A) so... similar electrical specs, more or less?


Russian 6p7s or G-807 are electrically equivalent (for the datasheet I have), to my knowledge @SonicTrance have some experience with 6p7s and even used some in the past. When i bought mine directly to an Ukranian seller it was not so expensive 5€ by tubes for 1960 Foton. (Latest price i got from 2021 was <= 8€, but it is now a bit compromised to get stuff out of Kyiv/_Kiev_)


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## OctavianH

Switching to GEC E3375 I went more to an EL34 type of sound. But what is really interesting to mention is that after trying several inputs I stopped at RCA VT-229. So I find again good synergy in the GEC + RCA combination and this confirms my theory. Regardless of tube type, which depends on your taste, you'll find better synergy in specific "manufacturers pairing". In my case, GEC always goes well with RCA. That's an interesting finding, I was usually combining british outputs with american inputs, now I go more specific with GEC - RCA.

GEC ATS25 + RCA 6N7G
GEC E3375 + RCA VT-229 (6SL7GT)
GEC KT66 + RCA 6N7G.

Hmm.


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## OctavianH

A small preview of what's to come. 





But we need to wait for adapters, to measure. This time I'll go around Vgrid=-40V for these. We will see.


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## Isaacc7

OctavianH said:


> Switching to GEC E3375 I went more to an EL34 type of sound. But what is really interesting to mention is that after trying several inputs I stopped at RCA VT-229. So I find again good synergy in the GEC + RCA combination and this confirms my theory. Regardless of tube type, which depends on your taste, you'll find better synergy in specific "manufacturers pairing". In my case, GEC always goes well with RCA. That's an interesting finding, I was usually combining british outputs with american inputs, now I go more specific with GEC - RCA.
> 
> GEC ATS25 + RCA 6N7G
> GEC E3375 + RCA VT-229 (6SL7GT)
> ...


Interesting. I have several Sylvania 6sl7 and a Tungsol 6c8g but no RCA 6sl7. In my system the e3375, and especially the Mullard el38 don’t pair well with my 6sl7.


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## Krassi (Apr 4, 2022)

I got a lot of stuff today including the amp.
First of all.. WOW! i am amazed by the 807 sound.

Really interesting compared to my old triode amp with 6P15P-EB tubes.

i directly switched the russian 807 and unknown 6sl7 against a pair of smoked glass mullard 807 and a sylvania 6sl7wgt.
Well so far so good !

I guess i need some time and comparing to get the different styles of all those tubes.. its lovely that they cool down fast and can be changed pretty easy.
well more pictures to come! And this stuff doesnt break the bank like 300b

i also scored me two used ats-25 super cheap and maybe 2 new more for a bargain price...
Well crap! collecting tubes will be my next money grave and i need a rack to store them


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## OctavianH

Isaacc7 said:


> Interesting. I have several Sylvania 6sl7 and a Tungsol 6c8g but no RCA 6sl7. In my system the e3375, and especially the Mullard el38 don’t pair well with my 6sl7.


My impressions might be subjective. Take all with a grain of salt, all might be amp dependant.


Krassi said:


> First of all.. WOW! i am amazed by the 807 sound.


I am really glad you enjoy them. Tell us more.


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## Krassi (Apr 4, 2022)

Well soon 
i couldnt turn up the music as much as i wanted after 22:00 but first impression was that the bass in sounded more solid and live music seems more vivid when i listened to some songs that i listen to often. i was to tired so changing 4 pairs of 807 would be the first thing to try out tomorrow 

i will also make some closeup shots of the tubes. they look all the same on the first glance but all have different details.
So more to test tomorrow .. my coral horn speakers really enjoy this new amp.


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## OctavianH

Krassi said:


> Well soon
> i couldnt turn up the music as much as i wanted after 22:00 but first impression was that the bass in sounded more solid and live music seems more vivid when i listened to some songs that i listen to often. i was to tired so changing 4 pairs of 807 would be the first thing to try out tomorrow


Take your time, the biggest virtue in this hobby is patience not the number of pairs you try every day. From time to time I loose it and later I realize that I was wrong.


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## Krassi

Well you are right and i cant stop smiling after listening to it today. 
The sound is on steroids.


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## Krassi (Apr 6, 2022)

Holy moly.. i couldnt believe it first but i can recognize a real difference in the sound when i changed the 6sl7 tube!

i had the combo 2x RCA 807 tubes that you described as "more bass" tubes.
                           1x Silvania 6sl7 wgt. yesterday.

i got a RCA 6sl7 gt smoked glass today and changed its with the silvania..
the difference is quit noticeable. Bass is much more energetic and i can really feel my sofa is vibrating more from it 

Very interesting RCA 807 and RCA 6sl7 gt is much bass heavier than before. But lacks a bit the clarity from the silvania and punches more 

Pretty amazing. seems like the 6sl7 does make a lot of coloring on my amp. The owner of my amp also told me to experiment with 6sl7 tubes.
Might be some placebo since i was tired as **** since the last days.
Well but the RCA 6sl7 gt smoked glass seems like a bass booster and did what i expected from your description of it.
A bit like "Bassbucket".

"The Necks - Hanging gardens" is pure goosebumps energy with this combo. Strings from bass are really kicking.

But its actually to much for me.. well ill get two more 6sl7 and thought about gettin a 6188 Philips and whatever i can shoot on the bay or find in european old stocks. 





Also look what i got today


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## OctavianH

Krassi said:


> But its actually to much for me.. well ill get two more 6sl7 and thought about gettin a 6188 Philips and whatever i can shoot on the bay or find in european old stocks.


You can try to combine RCA 6SL7 with other pairs of 807 with less bass. I usually prefer to combine in contrast.

Regarding ATS25, well mister you just entered the aristocratic league. Enjoy and let us know what you think of it.


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## Krassi

Yep ill try this.... well tomorrow. its to late right now and the amp is in silent mode to not kill the neighbors 
I plugged in the sylvania again right now. Even with low volume my hornspeakers sound great.

Its just one. it was in a big bundeswehr (german military) stash of 15 tubes for all together 10 euros! 
second one incoming so i can try a pair 
i will get the last 2 from a belgium shop for 41 bucks including shipping also!

Whats interesting is that they again look different in detail than all the other 807 tubes that i got. ill do some closeup shots once i got them all.
Those ceramic bases are really much nicer than plastic.

Well its damned fun to change the color of the amp with tubes. And collecting them is a bit like pokemon


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## OctavianH

Krassi said:


> I plugged in the sylvania again right now. Even with low volume my hornspeakers sound great.


RCA 807 + Sylvania 6SL7 are a great combinations, both complementing each other very well. Remember that if you want to do the reverse combination, you can go for Sylvania 5933 + RCA 6SL7. I have here 2 pairs of Sylvania 5933 and I quite like them.


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## OctavianH

An evening with style with ATS25.


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## jonathan c

OctavianH said:


> An evening with style with ATS25.


Definitely with style!…Stein?


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## OctavianH

jonathan c said:


> Definitely with style!…Stein?


Better than this, Dr. Stein.


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## OctavianH

A little bit of fun and a nice idea, EL3N with ATS25. Definitely not bad, powerful sounding.


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## OctavianH

Ah, Friday Beerday. Well, let's start with 6N7 because I liked what I heard with my RCA 6N7GT.





If I have a pair, I usually listen to these in the 6J5 slot. I have to admit I am not yet aware of the differences between these in the 6J5 sockets with triodes at 2mA in parallel or in the central double triode socket via adapter at 4mA. I'll have to dig into this.


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## Krassi

Here is teafriday with ATS-25 and some wonky miles davis albums.

Will do some nonstop sofa testing today 

Actually this was really unexpected! I got one tube from a german seller. Well since i was very friendly (well as usual because there is no reason to be like a butt) he wanted to send me "a gift"..

..Well the gift was another matched ats-25  . well thats nice!
...well one seems wrecked ;( well thats not nice, but i still have another one here to try later. 

had to check first with some valvo 807 that not my dac or cables are broken.


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## OctavianH

Krassi said:


> Here is teafriday with ATS-25 and some wonky miles davis albums.


If you make tea friday I'll help the german economy. No problem. LOL


----------



## OctavianH

The exercise of today proved me that if a type of tube is in good synergy with another, most probably the manufacturer is just another flavour. I liked ATS25 with 6N7 and all my 6N7 from my collection went well. Of course, some were better than the others but all were more or less nice. I have to explore more from 6N7.





It is hard to understand why many ignore the 6N7. Not a lot of information, not many using these. No problem, I am here.


----------



## triod750

6N7 is not a fancy tube. ECC31, 32, 35 are fancy tubes. Ignorance is no bliss to your wallet. Money is a bliss to your stash. Life is full of choices. Safe bets are safe. I could go on and on...
Cheers...


----------



## OctavianH (Apr 8, 2022)

triod750 said:


> 6N7 is not a fancy tube. ECC31, 32, 35 are fancy tubes. Ignorance is no bliss to your wallet. Money is a bliss to your stash. Life is full of choices. Safe bets are safe. I could go on and on...
> Cheers...


From time to time I read also "DIY" forums where people knowing much more than me, at least from electrical side, discuss their designs and so on. I do not understand everything they write but many were recommending 6SN7 instead of 6N7 or 6SL7. Most probably there are some electrical advantages, but in my case I can say the 6N7 and 6SL7 work perfectly on my amplifier and I prefer them to the other more expensive types. I am lucky.


----------



## triod750

OctavianH said:


> From time to time I read also "DIY" forums where people knowing much more than me, at least from electrical side, discuss their designs and so on. I do not understand everything they write but many were recommending 6SN7 instead of 6N7 or 6SL7. Most probably there are some electrical advantages, but in my case I can say the 6N7 and 6SL7 work perfectly on my amplifier and I prefer them to the other more expensive types. I am lucky.


As with pudding, the proof is in the eating. If you like what you are hearing, what more is there to ask for?


----------



## Krassi

Ahh its the RCA inputs that are wonky on my amp.. well some foam fixed this and now they work! 

Well but strange thing is once i put them back in after a minute one channel is dead again when i plug in the ATS-25
Thats some weird sht. Unplug and some 807 RCA in and everythings good again.

Need to test more at least my amp is not fkd or something.

Well cheers!


----------



## OctavianH

Krassi said:


> Well but strange thing is once i put them back in after a minute one channel is dead again when i plug in the ATS-25
> Thats some weird sht. Unplug and some 807 RCA in and everythings good again.


One thing I would do, to isolate the issue, is to put the same tubes reversed (the one you had on the left socket on the right one and so on). Then if the problem reproduces on the other channel is the tube, if not maybe an internal problem of the amplifier. If it is the tube, then you can replace that one with the 3rd one and repeat. I am not sure if this process is not damaging the amplifier in any way, maybe you can call the one who built it? This seller tested those tubes? I have here 5 pieces and all work fine.


----------



## Krassi

Yes of course. An i have a third one i can also try and mix. My amp really has some pretty wonky rca connections that i need to fix in the future.
Well if this doesnt work than its also no problem. i am pretty happy with the tubes i have at the moment


----------



## hpamdr

OctavianH said:


> The exercise of today proved me that if a type of tube is in good synergy with another, most probably the manufacturer is just another flavour. I liked ATS25 with 6N7 and all my 6N7 from my collection went well. Of course, some were better than the others but all were more or less nice. I have to explore more from 6N7.
> 
> 
> It is hard to understand why many ignore the 6N7. Not a lot of information, not many using these. No problem, I am here.


6N7/G/T are very similar I had heating noise issues with some 6N7. I personally do not have anymore any 6N7 I only own 6N7GT Visseaux, Fivre and Haltron and the aristocratic ECC31 (NR73). What is very interesting with Haltron (UK rebranding company) is that you can get for similar box multiple constructions from manufacturer like Mullard or Phillips but also some Russian equivalent so if you buy only get the right picture....
On Eternity what i observed is that dual 6N7GT works really great in place of 6J5 !_ (I have some tube a bit unbalanced which can be perfectly paired and used this way ! )_


----------



## Krassi

I tried something new today.

Haltron 6sl7 GT together with RCA 807

Very nice so far quite similar to my Sylvania 6sl7 wgt in terms of clarity.
Wich is then pretty damned good 

really a nice pick. Should be a military version


----------



## hpamdr

Krassi said:


> I tried something new today.
> 
> Haltron 6sl7 GT together with RCA 807
> 
> ...


The construction seems to be "made in England" and usually you can get it for a reasonable price.
The 6N7GT (cv1958) is for less than 10$ a real bargain...


----------



## Krassi

Yep! "made from england" made me want to get one. It was 30 bucks and pretty ok if you consider most new ones start from 30 bucks. 
There is so much 80year old NOS stuff you can find and ill try to get some stuff so i wont have the problem that iam out of tubes in the next years


----------



## UntilThen

hpamdr said:


> I still have many tubes combo to test. I finally stopped to get new tubes and just enjoy music a lot.



These 2 statements deserve a comment from me. I've been focussing on quality tubes for Odyssey. While my collection hasn't been exhaustive, it is enough. There leaves only the GEC KT77 I would like to get my hands on but for now enough. Just enjoy the music as you say.



hpamdr said:


> I currently think that Eternity is one of the best audiophile purchase i did in the last 10 years but if i did not put my feet with first 500 bucks Elise, my path could have been totally different...



In 2019 when I review Oblivion (https://www.head-fi.org/showcase/oblivion-amp-by-ultrasonic-studios.24108/reviews), I made this statement

_@SonicTrance has created an amp that not only looks beautiful but also sounds great.
My prediction is that it will take off as more people come to know of it. Highly recommended !_

Since then, he has built more custom amps that are very interesting and worthy of best audiophile purchase. For me, that experience culminated with Odyssey. To this day, only 3 other persons have heard it. I'm very possessive of it.  My son, @xtiva and Simon has heard it. @audiargent will get his own black Odyssey soon and @DecentLevi will have Infinity custom remodelled to be a very close Odyssey.


----------



## OctavianH

Another small preview of what's to come. I could not resist the temptation, of course, because of @UntilThen


----------



## UntilThen

Haha you bought 2? Mine should be here tomorrow together with the TFK ECC81s.


----------



## OctavianH

UntilThen said:


> Haha you bought 2? Mine should be here tomorrow together with the TFK ECC81s.


Yes, I wanted to have a matched pair and Tom was very nice and matched them for me. I am thinking in the future to try a balanced Citadel, so I will need a few pairs of double triodes for the input section. I already have several quads of EL34/807. Of course, nothing is decided but I preferred to have 2.


----------



## OctavianH (Apr 21, 2022)

Yesterday it was Eternity's anniversary. Not 1 year since it was finished, but 1 year since I've received it.
Around 4000 hours of listening. Hundreds of combinations of tubes I've never listened  before.
Hundreds of posts here and hundreds of beers.





Since then my tube collection changed a lot. Mostly all 6SN7/6AS7 went away, including 6080/7236/5998 and so on. KT66/77/88 remained and the new comers started to appear: EL34/807/6N7/6SL7/6J5. I've changed also several  headphones, luckily I found what I was looking for in just one year. It is a performance, based on how many models are available and how hard it is to be able to listen and test them. In my case, reproducing my headphone line in a showroom is impossible, my amplifier is custom built and unique. My interconnects are also custom. But all is good when it ends good.

We will see where this new year will bring us. I am very busy lately with my personal life, so less time to experiment, I prefer to listen to music. I am still waiting for some adapters, then we start with A2900, 12E1, ECC81/82/83 and who knows what. To be sure I will not be bored I bought also adapters for 6BG6 and 6AR6. So nice times ahead. The only problem is that ATS25 is really hard to be removed from the amplifier. When I removed them I start to miss them, so let's hope I'll find another recipe to make me experiment more.

Here is the first time I've used it, checking the fixed bias voltages to be sure all is fine.


----------



## UntilThen

It's that how it came in, all wrapped up? I too haven't use my Woo Audio Wa22 with all the good power tubes for a while. It's sitting on the floor in the spare room.  

I shouldn't buy anymore tubes for Odyssey. There's enough to last zillion years.


----------



## OctavianH

UntilThen said:


> It's that how it came in, all wrapped up?


I think it makes sense to post all the pictures regarding the unboxing. Yes, it came like that but in a double box, external one was huge.





To have an idea about the size:





So around 600x600x600 mm. And inside, anti catastrophic packaging. LOL





The box where Eternity was stored is the one inside, so it looked like this the first time I saw it:





The next picture was the one from the previous post. It has some sets of fuses, it has 2/3 types inside for protection. And then my amps at that time side by side:


----------



## UntilThen

Eternity is a very attractive looking amp. Next to Feliks Audio Euforia which I once had.


----------



## OctavianH

Another thing which happened around 8 months after I've received it was to write some childish story about my purchase (attached). Do not take it too seriously, do not spend too much time with it, with high expectations about an "audiophile" revelation and analysis. It's just a story of a purchase from someone who clearly did not knew exactly what he was doing nor exactly what he was writing. But I have to say I find it funny because it's childish. What I plan to do is to try it again, after 1 year, to think again about how is see now the amplifier, how it paired with 4-5 headphones I had the chance to exchange during this year, what I would change to it, what it really made a difference. But for this I need time and this is exactly what I do not have now. And to practice my writing skills. Let's hope I'll do it. 

Ok enough with this, the past remains in the past and we need to live in the present times.



UntilThen said:


> Eternity is a very attractive looking amp. Next to Feliks Audio Euforia which I once had.


I have to admit that the new Feliks Audio Envy looks good with wood and so on but it is ... 300B.


----------



## UntilThen

That's the first time I've seen the Envy. It's an expensive amp. With addons it's over 7,000 euros. It's a beautiful looking amp.


----------



## OctavianH

UntilThen said:


> That's the first time I've seen the Envy. It's an expensive amp. With addons it's over 7,000 euros. It's a beautiful looking amp.


They've launched it recently, I think 1.04. But it was not a joke, seems a damn fine amplifier for those seeking for 300B. We will see in time how it compares to others.
In my case I prefer one much more flexible and which can use cheap tubes. With Envy we all know we have to buy in the end the WE 300B LOL.


----------



## hpamdr

OctavianH said:


> They've launched it recently, I think 1.04. But it was not a joke, seems a damn fine amplifier for those seeking for 300B. We will see in time how it compares to others.
> In my case I prefer one much more flexible and which can use cheap tubes. With Envy we all know we have to buy in the end the WE 300B LOL.


Thomas is also able to build 300B or 2A3 amplifier, Tubes are a bit expensive but not that much if you compare with rolling all kind of GEC output tubes 

As i'm very conservative, i still use my Euforia with GEC or MULLAR 6080 and 6J5 or Sylvania VT231 as input tubes as second amplifier setup and did not changed tube combination at every listening session since months.

On Eternity, I've tested 6BQ7A as input and 6M6 as output tube and it is a very good surprise when pairing with heddphone... 
I've also found some old ECC81/CV455 boxes and will have to test and mesure before trying in amplifier...


----------



## UntilThen

I do not desire other amps after Odyssey because that is the pinnacle for me in terms of audiophile sound.


----------



## triod750

UntilThen said:


> I do not desire other amps after Odyssey because that is the pinnacle for me in terms of audiophile sound.


----------



## UntilThen

triod750 said:


>



The world according to UntilThen.


----------



## Krassi

Nice unboxing pictures!

I stumbled upon 6c8g tubes and i wanna find out if the sound nicer then my 6sl7 tubes.
A china adapter for putting them in my 6sl7 slot and lets see how it sounds in some weeks.

Its so much fun to try so much stuff especially if those tube are not so damned expensive.


----------



## OctavianH (Apr 22, 2022)

Krassi said:


> Its so much fun to try so much stuff especially if those tube are not so damned expensive.


Yes, this hobby is very rewarding. I think you can try much more than those but first you need to find out more about your amplifier from the one who built it. It seems a custom model so there is no information or manual available. Check with him, ask about bias or other limitations, then you can try a lot. Maybe you will be able to go for 6N7/7N7/6F8G or even 6J5/6C5 via double adapter. 6SN7 can be nice but these are much more expensive so... first find out what you can do, then just find adapters. For these you have a nice offer here and he is very trustable, I also buy from him and he does almost everyting. Or you can go DIY and just buy parts and make your own ones, it depends on your crafting skills. In my case I have 2 left hands so so I let others help me.

PS. Have you solved your ATS25 problem?


----------



## hpamdr

Krassi said:


> Nice unboxing pictures!
> 
> I stumbled upon 6c8g tubes and i wanna find out if the sound nicer then my 6sl7 tubes.
> A china adapter for putting them in my 6sl7 slot and lets see how it sounds in some weeks.


*About 6c8G*, amplification factor is "only" 40 depending of your amp what makes 6SL7 nice sounding is low grid voltage and high mu... But all depend to you amplifier design !
A similar tube to 6SL7GT is the 7F7 (loctal), in Germany you can get some from old US stocks in old radio club.


----------



## Krassi

Well i havent tried those ats-25 since then .. ill try that sooner or later.

I asked the guy that build my amp and he said "no problem works with 6c8g but 6sl7 are the best sounding tubes on this amp in his opinion."
So it will be no Problem and i have ordered a nos 6c8g from rca to try this out.

i also read that those have less amplification than 6sl7 and are those predecessors.
Well its try and error and 3 "big Coke Cans" would look even more amazing on the amp.

i found a lot of sources for 6sl7. At least those are not so rare. 6c8g is pretty hard to find.
I think i already found what i was looking for with those jan  Sylvania and Haltron 6sl7 tubes and this confirms what the guy is telling me.


----------



## UntilThen (Apr 23, 2022)

I shall talk more about tube combinations that I like in Odyssey. There are many combinations that I like so I have to be selective. First on the list...

*Telefunken ECC801S and GEC KT66.*
Rectifier is GZ34. I have several GZ34 and I'm using Sittard now.

This combination gives the revelation and clarity of the TFK ECC81S with the GEC full body tone of KT66. It's the best of German and Great Britain house sound. Particularly enjoyable with vocals where the mids are forward projecting. The tone just kind of pop right at me. Piano chords are vibrant and vivid.


----------



## OctavianH

Well, I never tried until now Psvane KT88 with my beloved RCA 6N7GT. Not bad, not better than ATS25. Less sweet, drier. This is a combo to remember.





GEC remains magical, so I hardly wait to try 12E1 and also A2900. Soon.


----------



## OctavianH

And I've just realized I never tried KT88 with 6SL7. When I started my 6SL7 journey I was already on 807 so I never went this path. Good to know, we have to try this.


----------



## OctavianH

If other brave warriors of the Tube Rolling Order managed to put these on Elise, I had to return again to them, this time with a plan to evaluate more of their capability to reach my top list. Very transparent and clear, these were a little bit too analytical and synthetic sounding for my taste, but I guess they have a chance with a bit of sugar to reach the point I like. So ladies and gentlemen, Telefunken EL156 + Mullard ECC35.





Definitely not bad, even if a little bit bright for my taste. I wonder how these will look with the small GEC A2900. David and Goliath.

I am returning to several tubes I had not enough time to try in the past, making again a tour to assess them in context of my Final D8000 Pro.

PS. On the warm Elise I guess these are a killer match.


----------



## OctavianH

I played a lot with EL156 yesterday, passing through a few 6SL7/6N7 I considered warmer. One thing I like is the soundstage, everything is clean and wide. But the Telefunken sound remains and for me, this kind of signature cannot beat 807. It sounds "audiophile" but I never searched for that. Lacks emotion. Tight, clean, correct, but soulless. It is a good alternative from time to time but I remain for that emotional sweetness. I liked a lot ECC35 and CV1985 for them, a very good pairing. Also RCA 6N7 clear and grey glass.





I guess for classical these are killer, with that soundstage, they put the orchestra in front of you and all sounds clean and fine. But for blues, jazz or rock, well you might want more bass or a more cozy atmosphere. I have the same feeling when listening to Telefunken EL34 after Mullard EL34 xf2.


----------



## hpamdr

Even if i do not have EL156, this is exactly what i fell since many years TFK/Siemens/Sylvania tubes are precise, clear and usually dynamic but this kind of sound is more for SS lovers or for classical music.
For Rock, pop, ... the sound can be a bit too dry and not as emmotional than other brand like GEC, Mullard, KR, RCA...

Curently with Eternity I'm back with EL3N as output and CV455 or 6BQ7A in input listening a lot of blues  (sad mood)


----------



## OctavianH

I tried to force a little bit their signature but from my experience forcing is not always providing the best results. A good example is this RCA 6N7 grey glass which is boldening a lot all the frequency range, but the sound obtained is not natural.





In the end I realized they have a different signature and I need to keep them more or less in the same area.


----------



## OctavianH

But when the weekend comes, you put your weekend tubes. ATS25.





And next one on rolling... Doppelbock Dunkel. Good one, I like this one. After all it is Friday Beerday but this one does not share Telefunken/Siemens signature, this one has emotion and taste. LOL


----------



## OctavianH

Hmm, what to choose? Tough Saturday evening choices.


----------



## triod750

Pick a tall bottle 7N7


----------



## OctavianH

Hmm, I have only one RCA 7N7...


----------



## triod750

OctavianH said:


> Hmm, I have only one RCA 7N7...


Sorry; too short. You would need a taller   .  It's always something out of reach that counts...

Lacking that, you would have to pick something you have. Poor sod!


----------



## OctavianH (May 1, 2022)

triod750 said:


> Sorry; too short. You would need a taller   .  It's always something out of reach that counts...


In the Elise years when I was searching for 6SN7 and equivalents I had problems to find 7N7 in Europe. In the US these were selling very cheap (less that 10USD/piece) but in Europe there were only a few offers and much more expensive. I guess is the same now with 6BG6.

Later edit:

Does anyone know more about Thomson tubes made in France? For example this pair of 5933?


----------



## JazzVinyl

Likely 70's vintage:

https://en.wikipedia.org/wiki/Thomson-CSF


----------



## JazzVinyl

OctavianH said:


> Hmm, I have only one RCA 7N7...



Pretty sure all 7N7's (except some National Unions) were made by Sylvania - regardless of branding...


----------



## OctavianH (May 4, 2022)

JazzVinyl said:


> Pretty sure all 7N7's (except some National Unions) were made by Sylvania - regardless of branding...


At least soundwise my RCA branded 7N7 sounds like a Sylvania. But not only, for example these top markings, here near a Sylvania 6SL7:


----------



## OctavianH

I missed the clarity and soundstage of EL156. So I decided to give them more time. Unfortunately, my 6SL7 sounded a little bit harsh, so I had to go again for 6N7.





For acoustical music these are excellent. For electrical guitar a little bit too dry, and overall less forgiving than ATS25. You need to pair these carefully and most probably you will not find a combo to please all your collection. But specific records will sound spectacular.


----------



## triod750

I would want to know how these EL156 sound with triode wired EL42, made in Blackburn .


----------



## hpamdr (May 4, 2022)

For the ones who wants to support Ukrainian Market and like Russian Tubes : https://docs.google.com/spreadsheets/d/1SY4atOFrYfHkQOoZMmm9amvhuYP9EvxKu1ZXRc45fcY/edit?usp=sharing


adamkasumov55@gmail.com


----------



## OctavianH

triod750 said:


> I would want to know how these EL156 sound with triode wired EL42, made in Blackburn .


As long as adapters are doable, and most probably are, and the grid bias for 4mA @ 180V is under -13V I can do it.


----------



## hpamdr

OctavianH said:


> As long as adapters are doable, and most probably are, and the grid bias for 4mA @ 180V is under -13V I can do it.


To my experience, el32 (predecessor of el42) do not sound that good in Eternity than in Euforia. Bias is around -20V for some tubes... 

For input tube:
I really think that single 12AT7 league is a good compromise. Double 6N7/G/T a very permissive alternative.
For output:
I still like a lot EL39 with every style and find EL3N having a wonderful tone for Blues/70's Pop...


----------



## OctavianH

Finding pairs of 6N7 very cheap is not very easy, but I found a few singles so I'll have soon more. I really like these and you can obtain them for almost nothing.
Next step is ECC81/82/83 and maybe some 6C4. I have a few surprises planned, but I need to wait more before revealing them.


----------



## OctavianH

Hmm,  not bad at night.


----------



## OctavianH (May 8, 2022)

hpamdr said:


> I still like a lot EL39 with every style and find EL3N having a wonderful tone for Blues/70's Pop...


I followed your advice and indeed EL3N is very nice and full bodied for blues/rock. Guitars sound nice. I left the Fivre 6N7 on input but I plan to take these EL3N to the 6SL7 territory to see what is happening, a little bit of energy from 6SL7 will complement the EL3N relaxed sound and I expect a very nice flavour.





I never tried EL3N in output with D8000 Pro and I like a lot what I hear. This was a good suggestion. Bias is around -4.4V for 20mA but works well.

Later edit: one remark related to EL3N + 6SL7. Gain is a little bit too much here. Volume knob almost at minimum with Low Gain setting.


----------



## triod750

Would be interesting to know how 6C4/CV133 would perform as input there  .


----------



## hpamdr (May 9, 2022)

triod750 said:


> Would be interesting to know how 6C4/CV133 would perform as input there  .


The predecessor 6L5/G would be more interesting here but being back to the standard 6SN7 or 6J5 gives good result for me (even siemens e188cc) 
Amplification factor <= 20 is OK (with two 6N7, we have around 40 and 6sl7 around 70)


----------



## OctavianH (May 9, 2022)

What amplification factor has EL3N? I cannot find it in the datasheet.

In EL3 I see 28? (later edit, typo, wanted to write 23)


----------



## hpamdr

OctavianH said:


> What amplification factor has EL3N? I cannot find it in the datasheet.
> 
> In EL3 I see 28?


I measured for Eterrnity points (4mA/180V/-8.15V) and (20mA/200V/-6V)  Amplification factor goes from 19 to 22 we could consider 20 as a good compromise !
// This is also why EL3N in input or driver gives good results for 6J5 tuned amplifier 

See graph and measure for EL3N stripped as triode.




measure for Input:




measure for output:


----------



## SonicTrance

hpamdr said:


> I measured for Eterrnity points (4mA/180V/-8.15V) and (20mA/200V/-6V)  Amplification factor goes from 19 to 22 we could consider 20 as a good compromise !
> // This is also why EL3N in input or driver gives good results for 6J5 tuned amplifier
> 
> See graph and measure for EL3N stripped as triode.
> ...


Well done! Good info to have!


----------



## OctavianH

triod750 said:


> Would be interesting to know how 6C4/CV133 would perform as input there  .


This will be soon doable. If you have a preference for output to try with these tell me. These are my 2 pairs of 6C4, I am really curious about them because the prices are nice.


----------



## hpamdr

I personally mark the pairs on the back instead of painting a leprechaun hat on the top 
You will also have to cleanup the pin a little.


----------



## OctavianH

This is how the seller sent them. But I guess they work fine and this is all that matters. I had no involvment in any markings on them.


----------



## triod750

I suppose these are Swiss military markings? The Hivac manufactured pair sounds good in some combinations. Haven't heard the STC/Rochester.


----------



## OctavianH

For the fans of GE tubes, I have a surprise


----------



## hpamdr

Do you have type and datasheet ?
ECC82, ECC83, ? ?


----------



## OctavianH

hpamdr said:


> Do you have type and datasheet ?
> ECC82, ECC83, ? ?


Yes, these are 12A*7, I'll check all via DuoVac before using, so I will determine the grid bias. They have to work in Eternity in input socket via 6SN7 adapter. These work for both 12.6V and 6.3V heater.


----------



## OctavianH

EL3N in the evening, glow only on top.


----------



## hpamdr

I hope you enjoy EL3N in output with just  6J5 or GEC L63 in input give a try to Crusader from Saxon 
You will ear that it is a much better sounding tube in eternity than in Elise and if you want High Volume, you have plenty of power !


----------



## OctavianH

Yes, I like EL3N with D8000 Pro which is a much better headphone for this amplifier than Verite. I know all Saxon discography very well, one of my favourite bands.
I listen to Philips EL3N with some RCA 6SL7. Very good combo, 6SL7 adds some energy to EL3N and I find it pleasing. Good combination for rock music.

By the way, I was listening to Heavy Water, Red Brick City, it is Biff Byford from Saxon with his son, incredible band:



And as far as I've know they are already recording 2nd album. Damn, I need it!


----------



## OctavianH

Every new tube types need a little bit of preparation and today I had some time to take a look. I've said a few weeks ago that I will try a few noval small tubes and then stop. I am done with Eternity and I have tried almost everything I wanted. I am happy. Of course, after I said that I realized I'll add 2-3 more as a bonus because this is how it always happen. OK, said and done, I bought a few tubes tubes and since I liked a lot 6SL7 and 6N7 which have higher gain than what I was expecting to use (6SN7/6J5) I said it is fine to try the ones with higher gain from the 12A*7 family. Today I wanted to  understand a little bit what is happening with these. So I started to look at the datasheets of ECC81/82/83. From these, the highest gain is the ECC83/12AX7, followed by ECC81/12AT7 and in the end we have ECC82/12AU7. All seem to need the same adapter. All should work at 6.3V in the 6SN7 slot.

1) For ECC82 - 12AU7 I saw:




I think this might bias around -8V at 180V/4mA which I will use them. So it seems it is no problem.

2) For ECC81 - 12AT7 I saw:





This also seems doable, around -2.xV at 180V/4mA.

3) But things get more complicated for ECC83 - 12AX7 which has the highest gain and the bias should be very close to 0:





Now, I guess this can work fine at 180V/3mA and in that case bias should be around -0.4V. @SonicTrance What do you think about this?

Then said and done, I put a Tesla ECC83 on my tester to check it and measured -0.4V needed for 4mA (this specific tube tests a lot above 100%):





So it might be I'll need to keep these ECC83/12AX7 at 3mA to be able to bias them on Eternity or even 2.5mA. But it is very beautiful, I like it. Old Tesla EL34 were awesome so my expectations for this one are big.





I will  have to read more and ask advices, I am new to this territory and I am not sure I fully understand what I have to do.


----------



## SonicTrance

OctavianH said:


> Now, I guess this can work fine at 180V/3mA and in that case bias should be around -0.4V. @SonicTrance What do you think about this?


I'd use it at 3mA bias.


----------



## OctavianH

SonicTrance said:


> I'd use it at 3mA bias.



Thanks for confirming, this was also my assumption. I'll wait for the adapters then report what I hear when listeninig to these 3 types of small tubes, I am really excited because I think I am on a good path here to find nice things. 

But, until then, the fun has to continue and we cannot stop at RCA 6N7 or Fivre 6N7 because there are others selling cheap and sounding extraordinary. For example the Sylvania 6N7.

Here some pictures near my RCA clear glass 6N7:






Almost similar, I am not wise enough to read construction details and deduce the manufacturer, soundwise sounds like a Sylvania.





And getters:





And there is no better scenario to try these as EL156 or, later ATS25. But let's start!





Nice sound, Sylvania sounds thinner than RCA (as expected) but clean and coherent, I think the 6N7 warm sound complements nice the Sylvania style, and this tube will soon become special to me. I like it! Now since it is Friday, then only missing thing is the ... beer.


----------



## OctavianH

And a close picture in action. I'll wait for the night to see how it looks in low light. Damn how much I like these 6N7 nobody cares about. This warm full bodied yet delicate and energic sound which is able to bring life into EL156 which are technically unbeatable but lifeless when not paired properly. No problem, 6N7 is here and we are here to listen to it. Excellent finding was this tube.


----------



## OctavianH (May 14, 2022)

Next on Dallas, CBS/Hytron and Teleka 6N7.





These will be tried in the future, I have no idea about Teleka, it is clear to me it is not a manufacturer but a rebrander. Let's hope I will find out more about these. This is just a teaser. I am on a hunt for 6N7 and I love it.

Another later edit:

It seems this black glass tube is in fact a Tung Sol 6N7GT, and it sounds quite like a Tung Sol to me.





Later edit: RCA 6N7 and CBS/Hytron 6N7 grey glass:





Almost similar but not identical.


----------



## OctavianH (May 13, 2022)

Said and done. Weekend, we need ATS25.





Currently listening to the first Black Sabbath album, song The Wizard.

Later edit:

CBS/Hytron 6N7:





Not bad but I prefer Sylvania, somehow similar but Sylvania is special.

And the "Blackie" which honestly I like better than the CBS/Hytron:





This remains under evaluation, sounds quite nice and airy. Glow is killer.


----------



## triod750

You made me install my Tung Sol 6N7GT/G. It's an interesting tube. It is more forgiving to 'Me and Mr Johnson' (Clapton, E.) than Ken-Rad 6C5 are. With Adzam/Blackburn EL42 I get even more smoke .

(The 6N7GT/G on the glass is difficult to see on my tube and the glow isn't as strong as in your 'blackie').

Thanks for the inspiration.


----------



## OctavianH

Speaking of Blackie. Well, some Brimar 6V6G with the Tung Sol 6N7GT/G.





I wanted to revisit the 6V6 collection in the context of D8000 Pro. With Verite I did not like these, but with D8000 Pro things stand differently. This is another confirmation that, at least for me, D8000 Pro is a much better headphone more suited to my activities. And yep, an "all black" combo, quite classy.


----------



## OctavianH

Today is 20.05, exactly 13 months since I have received Eternity. And today is the day my last chapter of rolling will start. I measured, read, prepared and today we go live.
GEC A2900 with GEC 12E1 (CV345). Of course, this combination is only to get an idea about both types, new to me until now. But the result at first try is quite impressive.





A2900 needs a Vgrid = -2V at Vplate = 180V to reach Iplate = 4mA. But the fun part starts with the 12E1 which goes around Vgrid = -44.5V at Vplate = 200V for Iplate = 20mA.
Anyway, really nice sound from these, I'll evaluate it later, now I just wanted to check how and if these work fine. I stored them for a while, now I am able to use them.


----------



## OctavianH

Next test: Tesla ECC83 (12AX7). I was worried about this one because it requires grid around -0.4V for 3mA. But seems to work fine with bias set at minimum.





I have to dig a little bit about the gain here, because I was expecting that this one will need much less from the volume knob, now it is around the same level as 6N7 and I have to see why. Most probably at this operating point the gain is lower than in other conditions. However, the sound is nice, but about the sound later because now is only testing phase. 12E1 is very promising and this was important to me, because they are a part of a possible future plan, and I needed them to sound good. But more about this later.


----------



## triod750

I like the shape of this Tesla. That's all I can say  .


----------



## OctavianH

triod750 said:


> I like the shape of this Tesla. That's all I can say  .


Yep, I find it also funny. But Tesla EL34 NOS tubes impressed me and this one is not bad either. I do not understand much now, my focus is on the voltages/currents/adapters to check if all works fine, but none of these sounds bad. So, Tesla remains a nice brand in my book.


----------



## OctavianH (May 20, 2022)

OK, so measurements are done. 12AU7/6C4 need around -7V for 4mA... close to what I set for 6SN7/6J5/6C5. 12AT7 go around -2V and 12AX7 around -0.4-0.6V, here for 3mA only. As expected according to the datasheets.





Brimar ECC82 and a lot of light.





Now, it's time for a beer.


----------



## triod750

OctavianH said:


> Now, it's time for a beer.


Make it two, tonight!


----------



## OctavianH

triod750 said:


> Make it two, tonight!


Damn, only 2?


----------



## triod750

Two for every one you intended. Happy now?


----------



## OctavianH (May 21, 2022)

A sunny morning.






This 12E1 looks brutal.





And the small one:





And 12E1 from another angle, I find these tubes incredible beautiful.


----------



## triod750




----------



## OctavianH

triod750 said:


>


I remember I've read somewhere about these, but I cannot remember where. Help me.


----------



## triod750

I can't. Just saw the photo...


----------



## OctavianH (May 21, 2022)

triod750 said:


> I can't. Just saw the photo...


I think this was it:
https://forum.psaudio.com/t/telefunken-g73r/27693

Some claim these work 40000 hours and the sound seems ... nice


----------



## OctavianH

These small tubes glow nice. Now it's time for A2900. The full "GEC" setup.


----------



## OctavianH

Playing with more novals. Telefunken ECC801S.





I'll need months if not a whole year to understand these. But there is no hurry. Every step is a pleasure.


----------



## OctavianH (Jun 3, 2022)

My energy for rolling was at a historical minimum in the last 2 weeks because my "full GEC" combo of 12E1 with A2900 sounds very good to my ears. It is not a perfectly correct sound, a little bit too fat and too mid forced, but this forced sound is pleasing me. For rock and metal these guitars sound good in this scenario and everything goes well. However, I plan to have some rolling activities during the weekend. Tube rolling and also beer rolling.





But June brought some nice results:
1) I was able to test D8000 Pro with an average temp in my room of 23C and I had no problems because of the heat like I had with Verite and that full leather headband.
2) I started to understand something from the sound of these small noval tubes. I think these are warm and a little bit less detailed than 6N7 but the more tubey sound is pleasing. But here I am only at the beginning of the road, I will need months to reach a final conclusion. Again the 12AX7 and 12AT7 were for me better than 12AU7, most probably because of the higher gain, and the "sweet spot" was 12AT7. I will investigate more into this direction.

And in the end, I need to plan a tinkering session. I had stored somewhere a pair of NOS top cap for EL38/12E1 which look gorgeous. I plan to adapt my 12E1 adapters using these. Just look how beautiful these are:









Excellent. I like these a lot and I'll hope I'll find more and make all my adapters with this kind of top caps. These are looking much better than the white ones from the adapters we can currently order. The guy who sent me these for free when he shipped me some tubes, in the past, told me they were originally used on EL38.

Later edit:

Or maybe keep these for a possible upcoming amp, with detachable top cap connectors. 12E1 natively connected to a 6V6 output stage and these top cap connectors. Nice!


----------



## triod750

I could wear such a nice top cap myself and claim to be pope 2.0  .


----------



## hpamdr (Jun 4, 2022)

OctavianH said:


> Excellent. I like these a lot and I'll hope I'll find more and make all my adapters with this kind of top caps. These are looking much better than the white ones from the adapters we can currently order. The guy who sent me these for free when he shipped me some tubes, in the past, told me they were originally used on EL38.
> 
> Later edit:
> 
> Or maybe keep these for a possible upcoming amp, with detachable top cap connectors. 12E1 natively connected to a 6V6 output stage and these top cap connectors. Nice!


Anode Top Cap plug is really great for EL38, EL29, EL12spe, 6P7S... It is just more convenient for as my favorite tube is EL39 and in this case, i do not need adapter.
I have made my own adapters for Euphoria and also EL32 I have used both ceramic (Chinese) top cap and old "3 lips" from UK stock nude or with brown cap. I will not use anymore the ceramic ones they becomes lousy.
If you want to change it, try to keep the cable as long as you can and always try to verify that it is long enough to plug and unplug once the tube is on the adapter before soldering. If you have to change the cable, the best is to do it from the base and add a very small ferrite core on top of the soldier to minimize RFI noise...
Dismantling the adapter can be too risky..


----------



## OctavianH (Jun 4, 2022)

hpamdr said:


> Anode Top Cap plug is really great for EL38, EL29, EL12spe, 6P7S... It is just more convenient for as my favorite tube is EL39 and in this case, i do not need adapter.


I am strongly considering it for my next amplifier. 12E1 is a very good tube and the pinout compatibility with 6V6 (like EL39) makes me want to use it natively.
I also consider SS / tube rectification switchable and if possible triode mode and ultralinear. Not sure if this works on a balanced Citadel but until 2025 I have time to find out. Of course it would be nice 12/6V switch but... I think I want too much.


hpamdr said:


> Dismantling the adapter can be too risky..


I was thinking only to replace the existing top cap of the adapter with this one, I am not very motivated since the adapter works perfectly, so the benefit would be only to look better which honestly, it too superficial to make me start tinkering.

A picture from last evening. These top caps Deyan used on the adapters are hand made by him, not bad because you can fix them with a screw on the tube. However since that is plastic it reaches around 90-95C and in summer when I have around 24C in my room can be problematic. I do not expect it to melt, but you have to be careful when touching.





Anyway, this discussion reminded me that during summer we need water cooling. LOL


----------



## UntilThen

OctavianH said:


> My energy for rolling was at a historical minimum in the last 2 weeks because my "full GEC" combo of 12E1 with A2900 sounds very good to my ears.



Similarly, I found the GEC A2900 and GEC KT88 combination to be supreme. It just sound so right.


----------



## OctavianH

UntilThen said:


> Similarly, I found the GEC A2900 and GEC KT88 combination to be supreme. It just sound so right.


I cannot change GEC A2900 with GEC 12E1 for 2 weeks. Today I came with big plans of tube rolling because I want to try several things, but with 24C in the room and a good cold beer and this combo which checks mostly all of my boxes I cannot find energy to change and assess and so on.

A2900 is killer. A game changer in terms of input tubes.


----------



## UntilThen

OctavianH said:


> A2900 is killer. A game changer in terms of input tubes.



My only regret is that I bought just one tube and not a pair.


----------



## OctavianH (Jun 4, 2022)

UntilThen said:


> My only regret is that I bought just one tube and not a pair.


I think Tom can help you. As far as I know he has more.

Later edit:

A picture with this A2900 does help. We discuss about:


----------



## OctavianH (Jun 4, 2022)

Interesting discussions made me gather enough curiosity and energy to start rolling. This is the beauty of a custom made amplifier. It is very close to your needs and also very flexible. At first sight it might be more expensive than others made in higher numbers, but in the end, it is the cheapest solution. Because you own 100 amps in one and if you like tube amplification (this might be a factor) you can tune everything as you like. Today I had more time for music but I was lazy. In the end summer, beer and weekend. Everyone wants to rest and enjoy. But I wanted to listen to one of my favourite bands, Harakiri for the Sky. The band is not important, what is important is that this band needs a little bit of what I call "bite" on the higher frequencies area to sound as good as possible and here my full GEC combo was lacking something. GEC is aristocratic, rich and full bodied, killer sounding on mostly of the records I am listening to, but here ... well... I wanted a more sharp and aggresive sound. No problem, we have Tesla 12AX7 which is exactly what I need.






Some know that I always considered NOS Tesla (70s or 80s) a very good choice. I have around 8 pieces of Tesla EL34 bought rebranded and very cheap which are somewhere in top of my preference list. Actually they are second favourites after Mullard EL34 xf2. And Tesla is sharper, more aggressive sounding. What this Tesla 12AX7 (ECC83) made for me? Well it removed some warmness of the GEC A2900 and added a more crisp/sharp sound. This makes my Harakiri for the Sky sound good.

This is tube rolling, a way to tune, a hardware equalizer which makes you never get bored about your amp. It requires effort, it requires patience, might sound complicated if you use manual bias like me but in the end I control everything, I can check everything and I can reinvent my amp every time I need it. On Solid State I was not able to do this. I owned several nice amplifiers, Beyerdynamic A2 or Chord TT2 integrated one, they are no match for Eternity. Period.


----------



## OctavianH (Jun 4, 2022)

I am the king of off-topic so I can afford 2 more pictures. Telefunken ECC801S:





And Eternity with Tesla ECC83 and the GEC A2900 near just for fun:


----------



## UntilThen

Telefunken ECC801s is what I am using right now.   It's Sunday 5th June 2022 @1:07am. I had just woken up from sleep.


----------



## OctavianH

Here Sunday has just began. It is 1 AM. Timezones.





I am impressed about this Tesla ECC83. So my personal opinon that Tesla NOS tubes around 70s or 80s are a great value remains valid. This tube sells around 20 EUR (the most expensive ones) and less if you are looking carefully. It does not match the richness of A2900 but I think it really sounds great and can be a very nice complement to some warm outputs when you need a little bit of sharpness. Old Tesla tubes never disappoint me.


----------



## UntilThen

OctavianH said:


> I am impressed about this Tesla ECC83. So my personal opinon that Tesla NOS tubes around 70s or 80s are a great value remains valid. This tube sells around 20 EUR (the most expensive ones) and less if you are looking carefully. It does not match the richness of A2900 but I think it really sounds great and can be a very nice complement to some warm outputs when you need a little bit of sharpness. Old Tesla tubes never disappoint me.



My exact same impressions on the Tesla EL81 power tubes used in Oblivion. They were recommended to me by Max. I also have the Tesla 6AV6 drivers. There's a sweet clarity from these tubes and they certainly help if you're toning down the warmth in your system or you want to dial up clarity in your setup.

EL81


6av6


----------



## OctavianH

My Tesla ECC83 which is now on the amp has the same yellow logo. A very good tube. I also have a lot of Tesla EL34 which sound great to me. Tesla NOS are incredible value. If I am not mistaken, I read somewhere that early Tesla EL34 were made on Mullard equipment on Czeh republic. So basically they share the same pedigree as XF2 we all love. For me Tesla sounds harsher, but has a better extension on higher frequencies area. GEC and Mullard are aristocratic but polite, when you want to add some sharpness Tesla never disappoints.


----------



## UntilThen

Sadly my Tesla EL12 spez are humming and hissing like Monty Python. I had wanted these to sing but they make too much noise Now if only I could find a quiet pair.


----------



## OctavianH

Maybe the adapters? I had a small hum on GEC E3375 when I used them in my EL38 adapters but I have now a new pair of adapters made by Deyan. I did not had time to try them but I will report if the hum is gone. Eternity is a very silent amplifier, I barely had problems and even when I heard something it was not quite disturbing.


----------



## UntilThen

It's not the adapters. I use the same adapters with the quiet Telefunken EL12 spez.

My other problem is with one of my EL39 top anode cap. It keeps coming off even after I put superglue. Now I need to buy another EL39 because that tube has a very unique and great bass tone.


----------



## OctavianH

Do you find EL39 better than 807? For me RCA 807 is a bass king and sounds spectacular.


----------



## UntilThen

OctavianH said:


> Do you find EL39 better than 807? For me RCA 807 is a bass king and sounds spectacular.



Yes definitely and I'm not alone. @hpamdr loves EL39. You should get yourself a pair to try while NOS still exist for them.

https://www.ebay.com.au/itm/265079940208?hash=item3db7fee470:g:AW8AAOSww9BgRNhr


----------



## OctavianH

I might do that but for me 807 and 12E1 are incredible, so I am not really motivated. I advise all UltraSonic amplifier users to try ATS25 or 12E1 if their amps allow this.


----------



## OctavianH (Jun 4, 2022)

I made a promise not to take musical genre into this thread because it has no purpose. We love our amps regardless of the music we listen to.
However, I'll break that promise for this song. Avantasia and Tobias Sammet is so good that I cannot help myself sharing it. We have here helping a vocal from Norway, damn he is incredible. Mr. Jørn Lande. And let's not forget we have Hansi Kürsch from Blind Guardian. German heavy/power metal was always a delight for me.



I will stop here, music is just music but this is above normal level. I was listening today to a lot of bands, some aggressive and some soft. Avantasia always remains.
For curious people I tried today a lot of stuff, Mayhem, Marduk, Deserted Fear, Entombed, Hammerfall, Black Sabbath but in the end decided to switch to Avantasia.


----------



## UntilThen

Rolling in the Amperex 12ax7 and Philips Miniwatt 6CA7 double O getters. These power tubes are the cheapest in my NOS collection but they still cost $350 a pair.

Odyssey in this setup hits the notes right, with the NOS EL34 sounding so sweet and yet with sufficient tightness and control.


----------



## OctavianH

I remained on the Tesla 12AX7. I use it at 3mA because bias is close to 0V. The plan is to keep it around 50-60 hours and then make an assessment about it.


----------



## hpamdr

Currently i found a good compromise with 12AT7/ECC81/CV455 as input Tube.  It gives wonderful result with EL39, 6P7S,... _(All output tubes i bought for 25€ by pair)_


----------



## OctavianH (Jun 7, 2022)

Even if I do not have here EL39 for me the 807 sounds closer to it, according to what I hear and what I read during the years about EL39. So I guess we both are somehow exploring similar paths. I had a lot of nice things to say about Tesla ECC83 (12AX7) on Saturday, but leaving it for more 20-30 hours on the amplifier (yeap, on Sunday I listened almost all day long to it) made me observe a huge improvement. I was sounding nice, but now it is sounding spectacular.





While listening to it I read several threads or comments to different shop listings, for example here. According to the markings on it I see "DP" which means as far as I know May 1960. From the link:



> Seems like Tesla sourced the tube internals from RFT E. Germany and evacuation/production was done in former Czechoslovakia.


----------



## OctavianH (Jun 7, 2022)

I finally had a chance to get a taste of 6C4. These are almost suitable to my fixed bias setting, measuring around -7.1V for 4mA.





Nice and spacious sound, it will be a fun experience. First impression is: delicate and wide. Less energy or sharpness than others but these compensate on other level.
Yeap, now it makes sense to me to dig and understand more. I have one pair CV133 KB/FD (on the amp) and one CV133 KB/H.

@SonicTrance How dangerous are 5mA for my input stage? On my fixed bias setting these go at startup around 5-5.1mA which is around the upper limit of what you advised. I can, of course, put these on manual bias and tune a little bit down but it is comfortable to keep them on fixed bias if 5-5.1mA are not damaging anything of those MOSFETS and what I have there.


----------



## SonicTrance

OctavianH said:


> I finally had a chance to get a taste of 6C4. These are almost suitable to my fixed bias setting, measuring around -7.1V for 4mA.
> 
> 
> 
> ...


5mA is fine but don’t go any hotter than that. I guess they settle at less than 5mA anyway?


----------



## OctavianH

SonicTrance said:


> 5mA is fine but don’t go any hotter than that. I guess they settle at less than 5mA anyway?


Yes, after 15-30 minutes they go around 4.8mA.


----------



## hpamdr

Disconova is nice album very refreshing. Back to GU50 / CV455 and HD850s. I really appreciate the CV455 as input tube unfortunately i only got some from UK which is a nightmare about import taxes in most European country.


----------



## OctavianH

I do not have the CV455 which many prefer but I play here with a Philips 12AT7WA which for me looks identical with a Mullard CV4024.





Most probably it is identical with one of these. In my case it is the brightest I have tried from these tiny ones but has potential.


----------



## OctavianH

If at first I kept the 12E1 fixed in the output position and tried several tiny 12AT/AX7 tubes, this week I made things in the reversed way. I tried GEC A2900 with several output and results were above expectations. For example the Telefunken EL156 which I always considered a little bit dry and synthetic sounding for my taste were nicely sweetened.





Good results I had also with RCA 807. It was a good week.


----------



## OctavianH (Jun 10, 2022)

Continuing on the same line: RCA 807 + Tesla ECC83. Exceptional sound, NOS Tesla never disappoints.





Or RCA 807 with Brimar 6C4.


----------



## triod750

Rolling instead of beering this Friday?


----------



## OctavianH

triod750 said:


> Rolling instead of beering this Friday?


Guilty! But I had a glass of wine. I'm getting older.


----------



## hpamdr

I got a glass of Cognac X.O. to celebrate a painful week.. And waiting for a quad of 12E1 brown base made in England for STC.


----------



## OctavianH

hpamdr said:


> I got a glass of Cognac X.O. to celebrate a painful week.. And waiting for a quad of 12E1 brown base made in England for STC.


Wow! A quad of 12E1. 😮


----------



## hpamdr

OctavianH said:


> Wow! A quad of 12E1. 😮


Yes made in England for STC by AEI  Black Plate/Brown Base .... But not GEC


----------



## triod750

Just add this...


----------



## UntilThen

hpamdr said:


> I really appreciate the CV455 as input tube unfortunately i only got some from UK which is a nightmare about import taxes in most European country.



I have one CV455 Footscray incoming from Langrex. At the recommendation of @jonathan c.
https://www.ebay.com.au/itm/274128808004


----------



## UntilThen

Sunday listening pleasure with EL11 and EL12 spez.


----------



## hpamdr (Jun 12, 2022)

UntilThen said:


> Sunday listening pleasure with EL11 and EL12 spez.


Sometimes, it is good to be back to the "reference set up". I think it was your goal to have an optimized amp for this particular combination and Thomas probably did a good job to reach all your expectations.


----------



## UntilThen

Tomas did indeed. This is indeed my reference setup and probably the only modern amp to use dedicated EL11 as drivers.


----------



## hpamdr

I got the 12E1 tubes, and made a British setup wit dual NR73 as driver and 12E1 as output.... (12E1 bias with Vg pretty low near -48V and with anode plug, no need for adapter  )
This is just a first round so I need more time to have detailled impression. But seems warm and detailed with good bass.


----------



## OctavianH

Yes, this is how I imagine EL39 on Eternity but with British flavour. 12E1 is for me an excellent output tube. I also wait for some STC metal base 12E1C so I will soon report more about this type.


----------



## Isaacc7

hpamdr said:


> I got the 12E1 tubes, and made a British setup wit dual NR73 as driver and 12E1 as output.... (12E1 bias with Vg pretty low near -48V and with anode plug, no need for adapter  )
> This is just a first round so I need more time to have detailled impression. But seems warm and detailed with good bass.


I was reading on DIYaudio about how 12e1 can go into thermal runaway. It was suggested that maybe they are safer in an amp with cathode bias because of that. Sounds like small changes in the screen grid voltage can cause larger swings on the anode. I’m not enough of a tech to know if running them in triode is enough to mitigate that or not. Anyway, might be worthwhile to keep an eye on them. I have avoided ordering 12e1 or derivatives because of my worry of fixed bias on my upcoming Odyssey. I’m going to live vicariously through you and see how they go!


----------



## OctavianH (Jun 14, 2022)

Isaacc7 said:


> I was reading on DIYaudio about how 12e1 can go into thermal runaway. It was suggested that maybe they are safer in an amp with cathode bias because of that. Sounds like small changes in the screen grid voltage can cause larger swings on the anode. I’m not enough of a tech to know if running them in triode is enough to mitigate that or not. Anyway, might be worthwhile to keep an eye on them. I have avoided ordering 12e1 or derivatives because of my worry of fixed bias on my upcoming Odyssey. I’m going to live vicariously through you and see how they go!


I've used them for around 2 weeks in sessions of more than 8h. Can you give me the link?


----------



## hpamdr

Isaacc7 said:


> I was reading on DIYaudio about how 12e1 can go into thermal runaway. It was suggested that maybe they are safer in an amp with cathode bias because of that. Sounds like small changes in the screen grid voltage can cause larger swings on the anode. I’m not enough of a tech to know if running them in triode is enough to mitigate that or not. Anyway, might be worthwhile to keep an eye on them. I have avoided ordering 12e1 or derivatives because of my worry of fixed bias on my upcoming Odyssey. I’m going to live vicariously through you and see how they go!


On many DIYaudio thread, amplifier are built for speaker output with different load and chasing output power and linearity. Generally with high output voltage and not designed for Large Tube Rolling capability.  

With Eternity, the output tube is used  in triode mode (K-G3 and G2-A with 100Ω) (This should be the same in Odissey unless you have also option for UltraLinear ?). We also use fixed grid bias and running only at 200V on the anode controlled by gyrator circuit. A good practice on eternity  is to wait for "stabilized" output current at 20mA. 
I have seen on some tube variation during the first 30minutes usually going up and down until tube reach internal Temperature, on Eternity it is not a huge variation (20%) as the Gyrator is also doing it job.

On Odyssey, this is not the same. You run with more voltage, more current and the bias is automatic. The only one that could respond about technical point is Thomas @SonicTrance. If you can afford getting a pair of GEC KT88 or Original GL no reason to go in 12E1 path. (Unless you like rolling and tube experiment)  

The comment we have about tube in Eternity is probably not the same on Odyssey due to technical difference and running not at the same point.


----------



## UntilThen

That's right. Technically @Isaacc7 amp is not Odyssey because Odyssey is cathode or auto bias. He needs a new name.   Maybe Penelope.


----------



## SonicTrance

hpamdr said:


> On many DIYaudio thread, amplifier are built for speaker output with different load and chasing output power and linearity. Generally with high output voltage and not designed for Large Tube Rolling capability.
> 
> With Eternity, the output tube is used  in triode mode (K-G3 and G2-A with 100Ω) (This should be the same in Odissey unless you have also option for UltraLinear ?). We also use fixed grid bias and running only at 200V on the anode controlled by gyrator circuit. A good practice on eternity  is to wait for "stabilized" output current at 20mA.
> I have seen on some tube variation during the first 30minutes usually going up and down until tube reach internal Temperature, on Eternity it is not a huge variation (20%) as the Gyrator is also doing it job.
> ...





UntilThen said:


> That's right. Technically @Isaacc7 amp is not Odyssey because Odyssey is cathode or auto bias. He needs a new name.   Maybe Penelope.


@Isaacc7 Odyssey will be a slightly different animal! It will have a grid biased output stage and have variable B+ (anode voltage) from around 250-400V. So, he can pretty much choose whatever operating point he wants within reason and current capability of the mains transformer. It’s also a push pull version of Odyssey.


----------



## Isaacc7

SonicTrance said:


> @Isaacc7 Odyssey will be a slightly different animal! It will have a grid biased output stage and have variable B+ (anode voltage) from around 250-400V. So, he can pretty much choose whatever operating point he wants within reason and current capability of the mains transformer. It’s also a push pull version of Odyssey.


I do wonder if the runaway situation I read about was due to unregulated screens or ultra linear operation where the screen voltage can vary. The more I think about it the more I think that running them in triode should solve that problem, right? I remember seeing a data sheet from GEC or Osram of one of the more exotic KT tubes and they said it should only be used with cathode bias due to how small changes in screen voltage can lead to big changes in current. @SonicTrance do you think that running tubes like that in triode will eliminate those dangers even if I’m using fixed bias?


----------



## jonathan c

UntilThen said:


> That's right. Technically @Isaacc7 amp is not Odyssey because Odyssey is cathode or auto bias. He needs a new name.   Maybe Penelope.


Iliad?


----------



## UntilThen

jonathan c said:


> Iliad?



The challenge is on to help Isaac find a name for his amp. Imagine a plague that has that 'name' on the amp. It becomes personalized.  

Now how exactly do you pronounce IIiad?


----------



## Thaddy

@UntilThen, where did you get those adapters for the EL12 Spez tubes?  May have to add those tubes to my list for my upcoming Odyssey.


----------



## Isaacc7

SonicTrance said:


> @Isaacc7 Odyssey will be a slightly different animal! It will have a grid biased output stage and have variable B+ (anode voltage) from around 250-400V. So, he can pretty much choose whatever operating point he wants within reason and current capability of the mains transformer. It’s also a push pull version of Odyssey.


My current amp, Dennis Had KT88 Firebottle, is cathode bias and is specifically designed to roll all sorts of tubes. Some people on other forums dismiss that kind of design because ”You can only optimize for one set of tubes.” That makes some sense if by optimize you mean maximum power at lowest distortion. It’s my understanding that when it comes to ”mismatching” tube output impedance with transformers the compromise manifests by lowering the maximum output power you can get at a particular distortion level. For example, with a badly mismatched set of tubes and transformer you might get 1% distortion at 1 watt but 15% at 10. Doing some math I realized that with my speakers and listening habits I am rarely ever going over a handful of watts. That’s probably why my current amp “sounds” so good and why I think that my Odyssey will too. Obviously headphone listening falls into the same power envelope. Running inefficient speakers at high volumes is a very different task. 

That’s my theory at least @SonicTrance do I have it about right? I am curious about your naming conventions. Is Odyssey the name for all custom “old school” amps or is there more to it?


----------



## UntilThen

Thaddy said:


> @UntilThen, where did you get those adapters for the EL12 Spez tubes?  May have to add those tubes to my list for my upcoming Odyssey.



https://www.ebay.com.au/itm/201784316782?

However Jack Woo said he could make me EL12 spez to KT88 adapters using nice teflon. I'm just too broke to get back to him after buying Susvara.


----------



## Isaacc7

jonathan c said:


> Iliad?


I might call it Persephone because of how my tube collection tends to grow in spurts and then I settle down for a while lol.


----------



## UntilThen

Isaacc7 said:


> My current amp, Dennis Had KT88 Firebottle, is cathode bias and is specifically designed to roll all sorts of tubes. *Some people on other forums dismiss that kind of design because ”You can only optimize for one set of tubes.” *That makes some sense if by optimize you mean maximum power at lowest distortion. It’s my understanding that when it comes to ”mismatching” tube output impedance with transformers the compromise manifests by lowering the maximum output power you can get at a particular distortion level. For example, with a badly mismatched set of tubes and transformer you might get 1% distortion at 1 watt but 15% at 10. Doing some math I realized that with my speakers and listening habits I am rarely ever going over a handful of watts. That’s probably why my current amp “sounds” so good and why I think that my Odyssey will too. Obviously headphone listening falls into the same power envelope. Running inefficient speakers at high volumes is a very different task.
> 
> That’s my theory at least @SonicTrance do I have it about right? I am curious about your naming conventions. Is Odyssey the name for all custom “old school” amps or is there more to it?



To that I say they have cotton wool up their ass. When Tomas has done with Odyssey with autobias, I hear nothing but bliss with any of the tubes I roll in. 

One other thing, you can have any name. As long as it's not Bcowen. You can get sued.


----------



## Isaacc7

UntilThen said:


> To that I say they have cotton wool up their ass. When Tomas has done with Odyssey with autobias, I hear nothing but bliss with any of the tubes I roll in.
> 
> One other thing, you can have any name. As long as it's not Bcowen. You can get sued.


If my thoughts are correct than both perspectives are right. If you’re only generating fractional watts then any distortions will be well below audibility. On the other hand if you are trying to squeeze every watt out of the tubes than the mismatch can cause real problems. 

I stumbled across this idea while reading some of George’s (tubelab) tests on DIYaudio. Some of his tests with the 6av5 showed different power output at 5% distortion depending on the load presented to the tube and the different kinds of feedback he used. He wants maximum volume though, I’m happy with a few watts.


----------



## SonicTrance

Isaacc7 said:


> That’s my theory at least @SonicTrance do I have it about right?


As for optimizing for a specific tube they’re referring to bias point and tube load (choke, transformer or resistor/gyrator/ccs..)
Regarding bias point your amp can be optimized for many tubes as you can adjust both the negative bias voltage as well as B+. 
The OTs have high enough primary impedance to not cause distortion with most tubes out there. 



Isaacc7 said:


> Is Odyssey the name for all custom “old school” amps or is there more to it?


No but your amp is close enough to original Odyssey! Granted it’s a push pull version with different bias scheme.


----------



## hpamdr

SonicTrance said:


> No but your amp is close enough to original Odyssey! Granted it’s a push pull version with different bias scheme.


@Isaacc7 @SonicTrance I'm pretty sure that the name will not affect the sound quality ! 
You should even call it "UltimaTe Odyssey" paying a little extra to get larger name plate


----------



## OctavianH (Jun 15, 2022)

I played a little bit today with GEC KT77 and these still remain my #1 preference for Eternity. They are for me in another league compared to all I have.






Even if I have several pairs, each of them is quite at the end of life or has, from time to time, problems (hum, noise, currents fluctuating and so on). This means I am not able to make a proper 1:1 and roll too much. These are very precious to me and I avoid to stop/start the amplifier several times per day when using them. Yesterday I tried to make a comparison with E3375 and 12E1 and after several sessions one of them refused to light again. I waited and today all works fine again but I will avoid as much as possible to roll when using them. I only hope these will still work for as many hours as possible and when they leave me they will not damage the amplifier in any way. But even if they do, I prefer to repair Eternity than to deprive myself from such an experience. Most probably reparation costs will be under the price of a new pair. LOL

Soundwise, well even if there is some similarity with E3375, those are no match for these. These are louder and more articulate, more bass, fuller sound which, while it is somehow liquid, remains very detailed and wide. It is sweet but does not have the defects of a sweet sound, it is forgiving but does not hide detail, it rounds somehow the sound but still keeping each small micro detail. It makes everything sound better. I guess is my ideal type of sound, very analogue somehow, the one I always try to obtain using other combos, but in those cases everytime I get closer I find a flaw. Here, well, all sounds good and you forget about the amp.

I did not thought anymore, after all my new discoveries, that these are so good, I remembered I liked them a lot when I first tried them but thought the difference should be smaller today. The only difference is that at that time I tried another pair, 7904 vs YH, so according to my date code table 12 years in between. I doubt there is a difference between older and newer produced GEC KT77, most probably they sound the same and the initial impression remains.





And another interesting thing is that I prefer EL34/KT77 with 6C4/12AU7 while 807 or 12E1 goes better with 6SL7/12AT7/12AX7. Most probably if I'll put these on a table with gain and so on I'll realize there is a connection between parameters which justifies my choice. And of course this depends on my preference and other components from the headphone line.

Future plan? To investigate and try to find out why my other KT77 pair made an incredible noise in one of the channels and I stopped using it. And pray this pair will work fine many hours from now on with only 1 ON/1 OFF per day.


----------



## hpamdr

When rolling on Eternity it is not as just unplug, calibrate, plug you really need to have all the capacitors well discharged between each step to be safe and let the tubes reach stabilized point. Another thing I've seen for me is that it is safer to unplug all tubes before biasing and do fine tuning for all when tubes are plugged. 
And yes input tubes and output tubes need a kind of synergy to make a great combo... 
About tube that do not light sometime, as a first guess you could verify it it is not due to poor connection  looking closely to the pin and lead soldering.


----------



## OctavianH

I always wait 5 minutes between each phase, for capacitors discharging, but you are right that from time to time I do not always remove both stages (if I roll outputs I leave inputs in place). I will be more careful with KT77, these are very special tubes for me. I doubt my actions are problematic, tubes are old and the problem appeared without removing them from sockets, I just replaced some inputs with the same bias (switched 2 pairs of 6C4). Anyway, you are right, I'll be more careful.

In the meantime I'll measure and check these extensively, then try them.


----------



## hpamdr

GEC KT88, you turned to be a real GEC afficionados KT66 KT77 KT88...

_(I only tested GL reissue to support Russian Economy)_KT66 have for me a real special tone but probably not as dynamic as you whish and KT88 are tighter and brighter those pair well with heedphone but less with HD850s to my ears and listening habit.


----------



## OctavianH (Jun 15, 2022)

hpamdr said:


> GEC KT88, you turned to be a real GEC afficionados KT66 KT77 KT88...


I always liked GEC but I never paid crazy prices on them. However, if I see a good offer, even untested, I usually bid and then measure. Until now I found quite good tubes if I took some risk. With DuoVac I do not really have a problem, because I do not put these directly on the amp. These are used, measure around 70% (if my measuring process was correct, I am still investiganting this, I measured: Vplate = 250V, Vg2 = 250V, Vg1 = -15V and considered 140mA as 100% with the tube connected as tetrode). I will search more to see if what I have done is right, according to this procedure I had 71% and 72% for these tubes. The other 2 are around same values.





And yes, I was able to try @UntilThen 's combo and I can say it is quite nice. Wide, neutral, somehow similar with EL156 when listening with A2900 but not so dry. Good combo, majestic I would say. This is the audiophile sound, KT77 is the blues sound. Here we need an orchestra and on KT77 we need an electric guitar.

What to say, with KT88/EL156/KT77/ATS25 I am done. I do not need anything else. My job is done, now I will wait to see what others are trying. This is The End for me.

Later edit: 

This tube looks brutal inside:


----------



## Thaddy

Very excited that my supplier has some nice power tubes in stock for the Odyssey I have on order.  I'll be getting, all NOS, GEC KT66's, Mullard xf2 EL34's, and some Tungsol 6550's.


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## hpamdr

OctavianH said:


> With DuoVac I do not really have a problem, because I do not put these directly on the amp. ...
> 
> This tube looks brutal inside:


@OctavianH what is your bias point measured with Duovac for these (200V / 20mA) ?


----------



## OctavianH

hpamdr said:


> @OctavianH what is your bias point measured with Duovac for these (200V / 20mA) ?


Because these are used I have to bias them around -20V for 200V/20mA (plate). A NOS KT88 should be around -25V.


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## OctavianH (Jun 16, 2022)

My rolling activities will end for a while. I am happy I was able to try all those tubes and get an idea about each one of them on my amplifier. I might continue in the future, but at the moment I reached the point I was announcing, to try some noval tubes and add 12E1 as a bonus. I am happy I've done it and I still consider 12E1 a great option for this amplifier. The GEC KT88 was also a surprise for me, not planned, just an offer I could not refuse.

I will go back to this combo, majestic. Bass strikes hard, when needed, vocals are in front and guitars are extremely fluid, especially solos. There is no high frequency rolloff like for example I head on Mullard EL34 xf2, which I call a "laid back" sound. Vibrant, rich but not exagerated, natural timbre yet thick and powerful. This is my endgame and I have foresaw this in the first months when I started to use the amplifier. While being somehow warm, it does not hide any detail, just rounds everything to sound good. Separation is excellent. Some might call it a tubey sound, but I call it an extremely technical tubey sound, rounded but very articulated and precise.





(input can vary, KT77 is bringing mostly of the sound shape while the input is only adding some nuance, important but not changing whole signature).

Now the plan is to see why the other KT77 pair made problems, because it worked fine one year ago.


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## UntilThen

Thaddy said:


> Very excited that my supplier has some nice power tubes in stock for the Odyssey I have on order.  I'll be getting, all NOS, GEC KT66's, Mullard xf2 EL34's, and some Tungsol 6550's.



I approved.  You're off to a flying start.


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## UntilThen

hpamdr said:


> GEC KT88, you turned to be a real GEC afficionados KT66 KT77 KT88...



I can't think of anyone not loving these GEC tubes, aside from the price. They are royalty. 



OctavianH said:


> And yes, I was able to try @UntilThen 's combo and I can say it is quite nice. Wide, neutral, somehow similar with EL156 when listening with A2900 but not so dry. Good combo, majestic I would say. This is the audiophile sound



Glad we're hearing the same thing. I use my GEC KT88 sparingly now. I can wear out the other tubes but I would want to keep these as new as possible.



OctavianH said:


> My rolling activities will end for a while.



As soon as I say that, a new tube arrived. The Footscray CV 455 just arrived. After 2 hours, I know that it is a top tube amongst my 12AT7s. As good as the A2900 and TFK ECC801S. I need more time to properly compare them.

Susvara arrives tomorrow. Then it's tube rolling all over again to find the best combination for this headphone.  

I've never regretted going auto bias. The convenience far outweigh the desire to get the bias 100%. In my view autobias gets close to 90 - 95 % and my ears wouldn't be able to detect otherwise. Besides my tubes run cooler and will last longer.


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## OctavianH

I think I'll keep the manual grid bias if I'll ever order another amp. While I fully understand its convenience, I remember the times when using Elise and changing different tube types, the amp needed to "settle" and sometimes was sounding right only after 2-3 ON/OFF and pauses. I guess the circuitry was adjusting and that bias was causing this. I have no idea how auto bias works on UltraSonic amps but since I've learned to use this manual one, I am all in for it, I never had that problem on this amp. I also like to have control. (Of course, subjective opinion, auto bias might be perfectly fine)


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## UntilThen

Yes everyone is different. You choose to do what you want. Isn't that the purpose of a custom amp?


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## hpamdr

I found a very good tube in my CTH tube box. A wonderful 6189 made in France in 1967 by RT in Suresne for Navy.
This tubes pair very well with 12E1 specially with Vocals (Listening Melody Gardot "Entre Deux" album).


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## OctavianH (Jun 16, 2022)

These tiny tubes have a lot to offer. I observed that I like KT77 with lower gain ones while 807 with higher gain types. 807 has gain 8 while KT77 is around 11. This is something interesting. I guess there is a formula behind which justifies this. A combination of gain for both stages. Because I liked Brimar 6C4 CV133 KB/FD I decided to try this Brimar ECC82 (12AU7) and it is nice.





But I have to behave today, I broke the rule of not stopping Eternity for rolling when using KT77.


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## hpamdr

I have a bunch of "small" tubes i used with my CTH and as i did not always get pairs the box was taking dust and i recently recovered it for the best 
With Eternity, it is a real pleasure to listen them again and pairing with different output tubes.
@OctavianH About some formula about good match between input and output tube @SonicTrance Thomas can give some about total gain and output power.


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## OctavianH

The real problem with these tiny novals is that the good ones are expensive. People know them and many amplifiers are using them, so many are selling at crazy prices. If I look into my whole activity since I have received Eternity, the greatest discoveries were 807, 12E1, 6N7 or 6SL7. These were tubes nobody cared about and sold almost for nothing. If I look at some 12A*7 I see prices above 6SN7. So the lucky ones have already some of them, others will only dream of. In my case, I'll stick with what I have, from which Tesla ECC83 is incredible value for the price.


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## SonicTrance

hpamdr said:


> I have a bunch of "small" tubes i used with my CTH and as i did not always get pairs the box was taking dust and i recently recovered it for the best
> With Eternity, it is a real pleasure to listen them again and pairing with different output tubes.
> @OctavianH About some formula about good match between input and output tube @SonicTrance Thomas can give some about total gain and output power.


Output power won’t change with different gain tubes. Different gain only changes how much you need to turn the volume knob to reach certain volume. Output power will stay the same regardless as the bias points are the same in Eternity.


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## OctavianH (Jun 16, 2022)

Evening with GEC KT88. I stopped again Eternity and removed the KT77 to let them rest after around 12h of use. I find GEC KT88 very polite sounding, balanced, wide and clean but very polite. I compare always with TFK EL156 which are somehow the same type of sound but those are more aggressive, bass punches harder and the overall energy makes those more lively. However, GEC KT88 has a very polite and aristocratic sound, and 3D placement is top class. I guess this is what makes these special.


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## OctavianH (Jun 22, 2022)

Today it was a very rewarding day for me, I was able to experience a piece of history. An unboxing of a quad of tubes from 60s unopened (well, one of them was opened by the seller to check them, the rest were my pleasure). So let me present you guys the STC 12E1C:





So take care, Glass! The box opened on the sticker side was the one opened by the seller. I was smarter to try to open them on the other side so the rest of the boxes look better. 3 have matching dates on the sticker while one is different, but when we look at them, here near one of my GEC 12E1 for comparison, we see that not all 4 are identical. First of all, the left and right ones have a slightly bigger glass. The one on the right seems to have an additional spacer. However, the rest seems identical.





In rest, all 4 very strong, I measured on my DuoVac around -48V for 200V/20mA and I was a little bit stressed not to exceed maximum negative voltage Eternity is able to provide which is around -54V as far as I remember. Some detailed photos, these are incredible beautiful tubes and they are in absolute perfect condition:









And in the end, around -47V on Eternity and these work like a charm. Of course, I will need many hours to assess them, but even now after 1h all I hear is very nice, good bass and very clean sounding, excellent tubes. I can listen to them 100 hours without having any regret, burn in is a pleasure. After one hour current started to decrease, so I have lowered several times the bias. I am checking them often so see how they evolve.





12E1 are incredible, nobody cares about them and sell almost for nothing, at least now, but sound on top with maybe the best tubes I have tried and here on Eternity are one of my favourites. Being compatible with 6V6 wiring except the anode top cap are making them a strong contender for a future amp. And yes now I regret I have not added optional anode top cap to my amplifier, this adapter would not be needed. Well, I can at least think I keep my amp internals cooler.

Ok, that was it, a piece of history. I was lucky to get these 2 types of 12E1 and I hope I'll have them near me for many years. I never had the chance to open tubes in such condition, so I had some emotions. I will remember this day. And people will start to hear more and more about 12E1.


----------



## UntilThen

Looks beautiful. So they are 6v6 equivalent? That's a pity because I can't use those in Odyssey.


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## OctavianH (Jun 22, 2022)

UntilThen said:


> Looks beautiful. So they are 6v6 equivalent? That's a pity because I can't use those in Odyssey.


I doubt these have something in common with 6V6. They bias totally different. I think these are on their own. 12E1C is the successor of 12E1. I have no idea if these work on Odyssey, and even if these work you will need adapters first. What is compatible is the pinout, you can use 12E1 on the same socket as 6V6 if you have anode top cap. This is very convenient because you can have an amp wired like mine and use all KT66/77/88/6V6/6L6 and so on and also these or EL39 without any adapter. This is the beauty of 12E1, and soundwise it is ... well I'll let other say it. 

By the way, I see on youtube several amps using these, interesting.



Translated with Google:







Hmm, interesting.

Later edit:

The first youtube video has some links in description to some korean blog:





Thank you Google, now I can read korean.


----------



## UntilThen

I cannot use 6L6 on Odyssey because the voltage is too low compared to KT88, EL34. Auto bias has it's limit. Can't cater to the whole spectrum of tubes. However I have enough to satisfy my needs.


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## DecentLevi (Jun 22, 2022)

I meant to post this to the main Ultrasonic Studios thread. See post here.


----------



## Thaddy

Personally, I don't understand how isolation feet can reduce hum.  I also don't understand why you use *so many *ferrite chokes, internally and externally.  But it if sounds better to your ears, I suppose that's all that matters.


----------



## DecentLevi

For anyone not on the other thread, I posted a good explanation here.


----------



## Isaacc7

OctavianH said:


> Today it was a very rewarding day for me, I was able to experience a piece of history. An unboxing of a quad of tubes from 60s unopened (well, one of them was opened by the seller to check them, the rest were my pleasure). So let me present you guys the STC 12E1C:
> 
> 
> 
> ...


FYI the s11e12 looks like the same tube without a top cap. Apparently the 12e1 and 6dq6 have the same pin out for what it's worth. The 6dq6 is a sweep tube and the 12e1 was designed as a pass element for voltage regulators (like the 6as7/6080!) so they are very different types of tubes.


----------



## Isaacc7

UntilThen said:


> I cannot use 6L6 on Odyssey because the voltage is too low compared to KT88, EL34. Auto bias has it's limit. Can't cater to the whole spectrum of tubes. However I have enough to satisfy my needs.


Aren't the 807 tubes essentially a 6l6a tube?


----------



## UntilThen

Isaacc7 said:


> Aren't the 807 tubes essentially a 6l6a tube?



They are but there's a difference between 6L6 and 6L6GC.


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## OctavianH (Jun 23, 2022)

Isaacc7 said:


> 12e1 was designed as a pass element for voltage regulators (like the 6as7/6080!) so they are very different types of tubes.


Indeed. This morning I thought about what you said you read on the DIY forums about 12E1. I will explain why. I have set grid bias for 12E1 to reach 20mA and usually at amp startup tubes draw a little bit more current than normal. But this goes around 2-3mA and after 15 minutes or around they start to draw constantly a little bit less. So since I am allowed to have on my output stage currents in range of 15-24mA I usually set tubes to draw at startup 23mA and let them when they are heated to stabilise around 20mA. This strategy went perfectly with GEC 12E1, no problem after some weeks of usage. BUT this morning I saw these STC 12E1C dropped in 2-3 minutes from 23mA -> 17mA. The pair is very balanced and I have no stress using them but I wonder why 6mA difference. I started to read and found this:






I do not really understand the part with "oscillating tubes". Can anyone advise why these are behaving like this? GEC pair works perfectly and even this one can be used but with the remark of the current drop around 6mA from startup until they stabilise.


----------



## hpamdr

OctavianH said:


> do not really understand the part with "oscillating tubes". Can anyone advise why these are behaving like this? GEC pair works perfectly and even this one can be used but with the remark of the current drop around 6mA from startup until they stabilise.


I cannot explain why but just confirm the same behavior in my side with 12E1 (AEI made for STC), it is also the case with some GU50 I have. Something even stranger, it starts a bit low, increase during next minutes and then decrease until they are ready (hot) 5 to 15 minutes after.  I just give a look and refine bias and wait a bit before listening 
Those tubes give a very warm sound with nice bass but not as clean than EL39 and not as Dynamic as Gu50 but as all is compromise it is good with Rock and Electric Blues. 
I found an old Gramont 6BQ7A which pair well specially with sweet female voices.


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## OctavianH (Jun 24, 2022)

Thanks a lot for confirmation. I switched back to GEC 12E1 and the problem is gone. 2mA maximum decrease after 15 minutes or so. I am very happy about this pair.


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## OctavianH

I tried the GEC 12E1 with Mullard ECC31 (in 6J5 slots) and also Fivre 6N7G (in the same 6J5 slots) with very good results.





So not only the tiny novals are a good options for these. We have plenty of options and possibilities. But well, today is Friday, Friday Beerday. Cheers!


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## UntilThen

Odyssey sound great with all tubes. These days I just do the rotation and get on with enjoying the music.


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## OctavianH (Jun 30, 2022)

Yes, it is true. However, there are several types which are favouring amp's signature. I am also in the rotation mode: KT77, 12E1, 807 and from time to time EL34, EL156 or KT88. On input I mainly remained with the same 6SL7, 6N7 or 12AX/AT7. In the last days 6C4 became more and more attractive to me. What is interesting is that none of these types were my focus when I ordered Eternity. Conclusion is that it is very hard to foresee how an amplifier would sound. It is the best way to wait and try it with some tubes you already have, then move step by step towards the desired direction. I do not advise to make a stockpile because most probabily when you will receive it you will start to make another one. It will not sound as you expect with the tubes you already know and for me KT66 was the lesson.
Patience, as always, is the most valuable thing we have in our hobby.


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## OctavianH (Jul 1, 2022)

Tube hall of fame, a good topic for me to pursue after my rolling activities have, more or less, ended. And today I have to give a prize to a very nice surprize I had a few days ago, when I received a bunch of tubes from a trade. I did not knew exactly what I will receive, I let the other person surprise me. And damn, I was surprised. Besides the tube pairs we agreed I have received a pair of ugly looking "Azdam ECC81". Pins were a little bit bent, what to say, I was reluctant to use these in my amp. But after a few minutes of cleaning when the logo and everything had to go, I was able to restore them in almost perfect condition.





And now the fun starts. I measured these biasing for my amp (180V/4mA) around -2.2V (both very balanced) which confirmed me these are 12AT7 (ECC81). But that's all I knew about them. In the amp the sound was solid, full bodied and somehow laid back, but without the high frequencies rolloff I usually expect at such a signature. Thick and extended on both higher and lower frequencies. So I had to research a bit to see what are these very nice unknown tubes. After the cleanup the only remaining markings on the glass were:

TK1
47F (4=triangle)

So, after some googling I found these are Philips made in Heerlen. Later I asked and I was told "This is the very first production Philips Heerlen ecc81." So my assumptions were right. And then, these became soon one of my favourites. I currently pair them with GEC KT77, so you can guess in which category are for me.

A picture to show a little bit more, for people interested:





And here a link which might be related:





Date and manufacturing codes seem similar. We have no side hole in plate and we have a D-getter with cross bar. Exceptional tube which still sells around 20 EUR.


----------



## hpamdr

12AT7 - ECC81 - CV455 -  sound really great in eternity. I have CV455 and phllips ECC81 this match well with almost all output tubes except EL3N or 6M6 which I prefer with medium mu tube. (*6C5* 6J5 NR73 6SN7 *7N7* ... around 20)  
You have a good amplification factor ~60 and a correct bias value < -2V and i think this is a spot point !


----------



## OctavianH

Yes, I learned that pairing is also a game of gain. I did not like 12E1 (5) with 6C4 (20) but I found good synergy with 12AT/AX7 or 6SL7. These 6C4 work nice with EL34/KT77. Of course, 2 posts above I was pairing KT77 with 12AT7 which might be an exception. How I perceive these 6C4 is much wider soundstage and more relaxed sound. Maybe because of better channel separation? I have no idea, but Brimar CV133 KB/FD is a killer tube. I will soon dwell more into this territory because I have bought more 6C4 pairs.
CV455 is also on my short list, can you advise about a specific construction? I've seen doube and tripple mica, halo and square getter and so on.


----------



## hpamdr

Unfortunately I do not have a huge collection to advise you on specific tube construction.
I personally do not have enough sensibility to make many difference between tube with almost same spec. What i have experienced is that slightly used tube sound a bit more  natural to me than the one i pull out of the box. 

I will got a tube lot with EC900 6HQ5 and 6AV6 to experiment higher mu. (I need to get B9G socket to do solid adapters) this should be good with 6V6 And 6L6 output tubes...


----------



## triod750

According to Valve Museum, 12AT7 was introduced in 1947. ECC81 is the European version. Does this mean that your pair is from 1947 or 1957?

Your tube is supposed to be marked Tk, not TK which means UCH42. (Sorry for being picky).


----------



## OctavianH

triod750 said:


> According to Valve Museum, 12AT7 was introduced in 1947. ECC81 is the European version. Does this mean that your pair is from 1947 or 1957?


I have no idea, but I have thought about this.


triod750 said:


> Your tube is supposed to be marked Tk, not TK which means UCH42. (Sorry for being picky).


Yes, it is most probably Tk. It is barely visible and I had to look several times on both pieces to see it. I'll share a picture.


----------



## hpamdr

OctavianH said:


> I have no idea, but I have thought about this.
> 
> Yes, it is most probably Tk. It is barely visible and I had to look several times on both pieces to see it. I'll share a picture.



This should be according to <here>: 
Tk1 first batches of ECC81     (Tube Type Tk + 1 as variant)
4 is heerlen 

*June 1948 (Batch 7) (Month F)*  or June  1957 post 1955 notation  (Tk3 started around 1957 for Blackburn )


----------



## UntilThen

This is where I bought my Brimar CV 455 KB/FB Footscray.
https://www.ebay.com.au/itm/274128808004


----------



## UntilThen

6SL7 is the highest gain tube in my amp and Tomas biased the driver on it. I've been using 6SL7 with a variety of power tubes for Susvara. Volume knob is no more than 12 noon which is less than half of max power in the logarithmic volume used in Odyssey.

This combination has been on for 2 days. Using the Psvane KT88 Tii as a daily power tubes so as to preserve the other nos tubes.


----------



## OctavianH

UntilThen said:


> This is where I bought my Brimar CV 455 KB/FB Footscray.
> https://www.ebay.com.au/itm/274128808004


Ah, Langrex. Nice. But I do not order anymore from them. I'll search for one elsewhere.


----------



## UntilThen

OctavianH said:


> Ah, Langrex. Nice. But I do not order anymore from them. I'll search for one elsewhere.



You could also try this. More expensive but I bought the socket savers from them and delivery was prompt.
https://pulsetubestore.com/products...4-12at7-factory-tested-plug-play-ready-to-use


----------



## OctavianH

I'll search for CV455 first in Europe, then I'll decide. There is no urgency. Many thanks for the link.

Continuing on my Hall of Fame I have to add here the GEC A2900. This is maybe the best input tube I own and ever heard. It is detailed, rich, vivid and natural sounding. I love to pair this with GEC 12E1 and call it my full GEC setup. There is only one thing I have against this tube: the price. So I cannot call it a winner. We all know my opinion, extremely expensive tubes are most probably sounding good, because otherwise nobody will pay for them. But the real winners are the forgotten, inexpensive ones which are close.





I have 2 types of this tube, or at least 2 types of GEC logo, because there is no difference between them. There is a more rare type, triple mica, which some claim it is better. Probably I'll never have the chance to hear it. But if it is better than this, I doubt I can imagine it.

OK, enough with halls of fame. I need a beer!


----------



## triod750 (Jul 1, 2022)

hpamdr said:


> 4 is heerlen


Yes, it's Heerlen but only if it is not a 4 but the sign for 'delta'. https://frank.pocnet.net/other/Philips/PhilipsCodeListAB.pdf
There are several versions of this list. This is pretty modern. See also https://tubedata.tubes.se/other/Philips/PhilipsCodeList.pdf
According to this, 4 would be Philips Eindhoven afd 22023 (2023). I don't know, it might be a 4 and Eindhoven. Myself, I would consult with @gibosi...

Edit. Checked the photo and to me it is the delta sign for Heerlen.


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## OctavianH (Jul 1, 2022)

triod750 said:


> Edit. Checked the photo and to me it is the delta sign for Heerlen.


Yes, it is the delta sign. This tube is way above my expectation and day by day I like it more.

Later edit:
It is very interesting how A2900 are described in this classifieds add. Nice!


----------



## triod750

If they are that good, why didn't he ask for $301?


----------



## OctavianH

triod750 said:


> If they are that good, why didn't he ask for $301?


Well, a matter of marketing. But those are that good, if you ask me. Personal opinon of course, I do not want anyone to judge me.


----------



## triod750

OctavianH said:


> Well, a matter of marketing. But those are that good, if you ask me. Personal opinon of course, I do not want anyone to judge me.


----------



## hpamdr

triod750 said:


> Yes, it's Heerlen but only if it is not a 4 but the sign for 'delta'. https://frank.pocnet.net/other/Philips/PhilipsCodeListAB.pdf
> There are several versions of this list. This is pretty modern. See also https://tubedata.tubes.se/other/Philips/PhilipsCodeList.pdf
> According to this, 4 would be Philips Eindhoven afd 22023 (2023). I don't know, it might be a 4 and Eindhoven. Myself, I would consult with @gibosi...
> 
> Edit. Checked the photo and to me it is the delta sign for Heerlen.


To be really picky, this is not a delta sign (Δ) but a lower right triangle (◿)  which the sign 4 is not that far ! (The picture of @OctavianH  was explicit enough).



You are right we should have asked to @gibosi to be sure.._ (One of the few tube master and collector I appreciate on Head-Fi)_

And as @Octavian said about UK dealer I Ordered many tubes in Great Britain in the past and now it is now a nightmare in France. Each parcel is opened and i have to pay Import Taxes and Carrier fee..


----------



## hpamdr

Today Visseaux day !
6J5 MGT as input and 6M6G as output all bias around -6.5V.


----------



## triod750

hpamdr said:


> To be really picky, this is not a delta sign (Δ) but a lower right triangle (◿) which the sign 4 is not that far ! (The picture of @OctavianH was explicit enough).


You are of course right but if you call it delta you will not mix it up with four which is another production unit in another city. Same company but different place. From now on, lower right triangle it will be .


----------



## OctavianH

hpamdr said:


> 6J5 MGT as input and 6M6G as output all bias around -6.5V.


6M6G and EL37 are types I wanted to try and renounced because of the price.

But it is interesting that 6M6G works for you at -6.5V. I always considered these electrically identical to EL3N and my EL3N work on output at -4.4V and on input (6J5 slot) at -6.4V.


----------



## OctavianH

Hmm, I think I'll have a fun week.


----------



## hpamdr

Have fun to measure and pair with duovac


----------



## OctavianH (Jul 5, 2022)

hpamdr said:


> Have fun to measure and pair with duovac


I am lucky that a very nice gentleman has already paired them. But I bought a bunch of others which I'll have to measure. For example a PCC189 tube which according to him sounds very good and works also on 6.3V heater even if it was designed for 7.6V as seen here. It seems compatible with my 6922 -> 6SN7 adapter so I'll give this a try.





While I do not want to buy any more tubes, I'll still have some fun with some cheap unknown ones. I am sure I'll have some surprises.

Later edit:

It seems I have to postpone my activities with this PCC188 because it measures totally different here than what the seller told me. So it needs investigation.

However, I wanted to try something new today so I went for 6CG7. This biases identically with 6SN7 so I can used this on my fixed bias setting.





6CG7 is very comfortable to be used on my amp, I have a fixed bias set for 6SN7 and I just press a switch and that's all. Soundwise? Well, this reminds me of 6SN7. But I might be wrong. What I wanted to report here is that 6CG7 works fine, at the same bias with 6SN7, as expected. Nothing new, but nice try.


----------



## OctavianH (Jul 8, 2022)

For the last 3 days I let my EL3N - KT88 combo to play. I need something warmer for these KT88 to be closer to my preferences. I also want to reach 150-200 hours with EL3N because I have the feeling these need more time to reach optimal peformance. so, a warm laid back sound and a nice picture. Bass is excellent with these.


----------



## OctavianH (Jul 21, 2022)

I had a lot of fun with the amp in the last days. The best times with such an amplifier are after the time you spend exploring, when you just try stuff based on what you listen, from the existing combos you've already learned about. At these times, you cannot go wrong because you already have an idea about the sound. I explored KT88 with some 6SL7 and liked them.





Then I've went back to ATS25 and check it a little bit agains my tiny noval ones.





And today I remembered  I have somewhere some E3375. A tube I've found out about by mistake, but it was one of the luckiest mistakes I've made. Exactly like discoverying the ATS25.





This summer is a fun one because D8000 Pro does not cause me any discomfort with the temperature, so no problems Iike I had with Verite last year. And this means more music. What I did not had time was to explore more from the 6C4 pairs I've obtained. But it is a good thing we still have a to do list.


----------



## Isaacc7

OctavianH said:


> I had a lot of fun with the amp in the last days. The best times with such an amplifier are after the time you spend exploring, when you just try stuff based on what you listen, from the existing combos you've already learned about. At these times, you cannot go wrong because you already have an idea about the sound. I explored KT88 with some 6SL7 and liked them.
> 
> 
> 
> ...


Tell me about the ats25, is it similar to an 807? Agree that the e3375 is amazing. Pretty much unobtanium these days though. It's weird, they seem to have disappeared but they never got very expensive.


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## OctavianH (Jul 21, 2022)

Isaacc7 said:


> Tell me about the ats25, is it similar to an 807? Agree that the e3375 is amazing. Pretty much unobtanium these days though. It's weird, they seem to have disappeared but they never got very expensive.


Yes, somehow. It is richer, more aristocratic sounding like a normal 807, but in my opinion it has the same sound shape of an 807. You can imagine a GEC 807, but somehow more towards the sound of the GEC L63 ST shaped grey glass (because there are 2 types of GEC L63 I have, the straight clear glass one and the grey glass ST shaped). It sounds soft, but still have great bass, a very special sound for me. I do not think something else can match it in that area. It is hard to describe, but you can hunt a pair, you won't regret it.

I'll try to explain more, it is towards this type of sound, if you can imagine an 807 shaped sound of this type:





These are my GEC L63 grey glass, quite different from the L63 clear glass brown base ones. Well, somehow in my mind I associate the ATS25 with these, something similar. But in an 807 approach. Well, if you can imagine that, you'll know how ATS25 sounds.


----------



## Isaacc7 (Jul 21, 2022)

OctavianH said:


> Yes, somehow. It is richer, more aristocratic sounding like a normal 807, but in my opinion it has the same sound shape of an 807. You can imagine a GEC 807, but somehow more towards the sound of the GEC L63 ST shaped grey glass (because there are 2 types of GEC L63 I have, the straight clear glass one and the grey glass ST shaped). It sounds soft, but still have great bass, a very special sound for me. I do not think something else can match it in that area. It is hard to describe, but you can hunt a pair, you won't regret it.
> 
> I'll try to explain more, it is towards this type of sound, if you can imagine an 807 shaped sound of this type:
> 
> ...


I've never heard a GEC L63... I have seen at least two GEC labeled 807, I stocked up on one of them. The Cossor 807 is a dead ringer for the GEC VT-60 and that's the one I have. In my system it is open, clear, and has prodigious bass. I have only seen ceramic based GEC VT-60 but the Cossor is available in both ceramic and a regular base. The plate looks identical so it might be worth looking for the cheaper brown based one. The way you describe the ats25 makes me think of the Mullard 807, another tube I have stocked up on. I see a smattering of ATS-25 tubes on ebay but not from sellers I recognize. I'll need 4 of them for my new amp so the price starts to become a factor too.

Edit: I should say that it's possible to find brown base Cossor 807 that have the same plates as the VT-60. Some other Cossor brown base look like the Brimar at a quick glance


----------



## OctavianH

I have a plan to revisit 807 in the next weeks. I am circling through EL34/KT77, 807/ATS25 and KT88. I have a pair of Mullard 807 here (xk1 B6J4):





I'll put this pair agains ATS25 to see how I see it. I remember I liked both but for me ATS25 was much better. At the moment I'll stick to this which sounds incredible:


----------



## OctavianH (Jul 26, 2022)

When you think all is over, things are happening and all starts again. I was able to measure 3 new types of tubes for Eternity. Unfortunately one pair is not usable at the moment for me, but I will report the measuring values because mabye @hpamdr will be interested in this type (at the end of the post), he can use it on his build of Eternity.

First try was Fivre 76. This is a very important tube because for me sounds close with my Fivre 6C5 brown base, but does not suffer from microphony like all my Fivre brown base tubes. This looks close to my 6N7G pair and it dead silent. For people with manual bias like me, my pair measured *grid = -9V for plate = 180V/4mA*. So do not consider it direct 6C5 replacement if you have manual bias. My 6C5 measure around grid = -6.xV for the same operating point. So be careful. I was 99% sure it is direct replacement and Voila. Good that I measured these before putting them to my stock bias setting and jump over 6mA.





Next try is something I never knew existed, but wiser and more experienced people offered me the chance to learn. So I was able to measure and try the 6L5 (G and full metal versions). At first, when seeing them, I said "ah, might be similar with 6L6" and how wrong I was. 6L5 is pinwise compatible with 6J5/6C5. It even biases close with those. Both my pairs were around grid = - 7.5V for the same plate = 180V/4mA. So an idea stronger like my 6J5/6C5, similar bias with my 6C4, for example.





Here is Visseaux 6L5. Nothing fancy to look but very good sounding. I think these are also close to 6C5/6J5 soundwise but I need more time, I never heard Visseaux before, it is brighter than Fivre for sure.

In the end I was able to measure a pair of RCA 37 and for Eternity this needs around grid = -15V for plate = 180V/4mA. My amplifier goes at maximum to grid = -13.xV on input but on output goes much more, over grid = -50V. I cannot put these on input, what I can do is to try these on a future amp. One mistake I've made with Eternity was to renounce on some output pentodes on input (like for example EL32). At that time I considered a grid of -12V to be enough for me. Well, this pair of RCA 37 which looks gorgeous contradicts me today. No problem. There is another Eternity where this can be an option, this is why I mentioned it.





That's all from the front line. Summary is:



> - 6L5 works and sounds fine with around -7.5V grid bias (on Eternity)
> - 76 works fine and sounds fine with around -9V grid bias (on Eternity)
> - 37 works on one of the Eternity builds around -15V grid bias



And now we enjoy Visseaux 6L5. These brighter/sharper tubes should be phenomenal on 807/12E1. On GEC E3375 I want back my 6N7 or warmer inputs.

Later edit:

I looked again at the post with the Visseaux 6J5 biasing around -6.5V. Well, those look in picture very close due to the metal body.


----------



## OctavianH

When you are a noob like me, Radiomuseum is here to teach you. This is why 6L5 biases the same as 6C4? Might be. Anyway good catch.


----------



## OctavianH

And a small remark related to ECC32. Works fine, grid = -3.3V for plate = 180V/4mA. For me sounds almost identical to ECC31 but maybe that's just me.


----------



## Thaddy

Does anyone have experience with Telefunken and RFT EL34's?


----------



## OctavianH (Jul 26, 2022)

Thaddy said:


> Does anyone have experience with Telefunken and RFT EL34's?


I have both in my collection, but barely used them. I tried them only on my amp and both are towards neutral/bright sound (well, compared with other EL34s).


----------



## Thaddy

OctavianH said:


> I have both in my collection, but barely used them. I tried them only on my amp and both are towards neutral/bright sound (well, compared with other EL34s).


So considering I already have a pair of Mullard XF2 EL34's they don't seem worth tracking down...


----------



## OctavianH

Thaddy said:


> So considering I already have a pair of Mullard XF2 EL34's they don't seem worth tracking down...


Depending on what you search for. Mullard EL34 xf2 is what I call laid back sound. Telefunken and RFT are for sure brighter.


----------



## OctavianH

I am quite impressed about these Visseaux 6L5. Very clean and crisp sounding, a little bit on the solid state direction for my taste but I have solutions for it. Anyway, interesting sound from some quite ugly tubes.






One thing I observed is that these have a little bit less gain than 6J5/6C5. I need around 10-15% more volume when using them and with tubes like 12E1 I go around 65% of Eternity's volume. So I prefer to use them with KT77/E3375 or EL34.


----------



## triod750

What are they like, compared to Siemens C3g?


----------



## OctavianH

triod750 said:


> What are they like, compared to Siemens C3g?


I would put them in the same category with Siemens C3g or Sylvania 7N7. But these are more relaxed and maybe an idea brighter.


----------



## OctavianH

I like a lot what is happening with GEC KT77 and GEC CV133 KB/Z. Going towards 6C4 instead of remaining on 12AU7 helped me to obtain a lot of british flavours at a decent price.





I will definitely keep this combo in mind, great synergy and overall, all my 6C4 sound quite good with KT77/EL34. For 807/12E1 I prefer higher gain ones. Combining tubes is definitely also a game of gains.


----------



## OctavianH

Violent storms are forecasted in my area and I am quite happy about that. Temperatures were too high for a few weeks already and I hope this wil bring things back to normal. But the weather forecast made me think a little bit about the current summer, which seems similar to what we will have from now on, and my listening sessions. Luckily for me the D8000 Pro never created me big problems. Even with 28C in the room I was able to listen to them around 16h/day. This is impressive. The pandemic changed the context of remote work for IT professionals and I had to learn to deal with it. But in the end, one advantage is that you are closer to your amplifier than before. And Eternity had no problem with the heat, tube sockets fixed on top of the upper plate are excellent in heat dissipation. I measured some temps through the ventilation holes and nothing was spectacular. Eternity is built to last even during long listening sessions during summer.





Several friends told me that only one pair of headphones and one amplifier is not enough to obtain the full experience. Well, my answer was simple that I try to reduce the variables around me while taking advantage of Eternity's flexibility, I want to tune more from the tubes and not roll headphones or change source. Ok, I can do that but I have only one life not 9 like the cat. So focusing on a particular direction is nothing wrong, when you know what you want from it. And might be cheaper.
I was always fascinated by the "holy grails" with prohibitive prices, but recently I learned that a different design and maybe unknown tube types might provide the same or a bigger pleasure. I still use KT77 and KT88 which  I consider expensive, but besides that 807, 6N7, 6SL7, 6C4 or EL34. Pairs of these are under 100 EUR. How they sound? Well, these are my favourite types for almost one year.

Storm is coming? No problem, we have beer!


----------



## OctavianH

No real reason to change something, but I was bored. These Mullard 807 make distorted guitars sound heavier. The Fivre 76 are just calming things a bit.


----------



## triod750

One gets so used to changing so even a change to different or even less good can be rewarding.....not?


----------



## OctavianH

triod750 said:


> One gets so used to changing so even a change to different or even less good can be rewarding.....not?


Being more relaxed with the amp lately I started to think more about the reasons I use it in the way I use it. I realized I get bored, and this was the cause I wanted more headphones or other amps in the past. After 1-2 weeks of something about which I cannot have anything against, I start to think about how others would sound. And I start to read and so on. The only looser is the wallet. Because a new equipment will bore me in the same way after some time. One root cause can be that many albums I like are produced very differently and cannot shine on the same type of sound. Other cause might be that I can enjoy exactly the same song while listening it from several angles. Each time I find something new, or I invent something new in it. A wise man once said and I fully agree with him: the only ones who really know how a song has to sound were the band in the studio. We are just guessing, with different amps, headphones and tube and so on. In my case I am lucky I can switch some tubes when I am bored, otherwise I'll buy some equipment ... and then try to sell it. LOL


----------



## triod750

Agree. I can make my amp sound very good with a recording and enjoy this very much. When I change for some other music the magic is gone, or might be. By changing input or output tubes I might be able to bring the magic back. It doesn't always work but quite often. There are plenty of lousy recordings out there, even if the music is interesting...


----------



## OctavianH

One thing I've observed with Eternity vs Elise was that this amplifier is somehow more unforgiving with certain recordings. With Elise things were more simple, it was adding a kind of warm tubey veil on everything and the effect was more or less the same on every record. Of course, there were specific songs benefiting more from it than others but all in all you could be happy without changing anything when you have reached equilibrium. Eternity is different, here there is no generic situation. There are 3-4 combinations which are more or less the best, but to obtain all you can from a record you need to choose a specific combination every time. I am not doing like this, but I have periods when I listen to 2-3 bands from the same genre/area and then I stay on the same combination. Later I move on to something different and need to change. Of course, this is a personal opinion and I listen only to rock music. My biggest challenge in a tube amp is the electric guitar tone. It is very hard to find a combination which will make it sound natural on a solo or riff. Those are very different types of, let's call it, tone. The solo has to be liquid, dreamy while the riff has to be crunchy and distorted but up to a point. Now, if you add the acoustical guitar, piano or vocals to the tables, more and more variables have to be considered.


----------



## triod750

Music is too complicated to push into an amp!!   

Wherever you turn there are drawbacks. We do our best to manage anyway and we enjoy the ride.


----------



## jonathan c

triod750 said:


> Music is too complicated to push into an amp!!


…and to pull out of an amp, to cram into headphone drivers/earcups…🥵🤣…


----------



## triod750

But via loudspeakers into a room are even more difficult to get right...
Right?


----------



## jonathan c

triod750 said:


> But via loudspeakers into a room are even more difficult to get right...
> Right?


…oh my…vibration nodes…asymmetric absorption & reflection…😳


----------



## triod750

Push-pull music is hard work...


----------



## OctavianH

To live transformer coupled or output transformerless, that is the question.


----------



## SonicTrance

OctavianH said:


> To live transformer coupled or output transformerless, that is the question.


Just to let you know there’s another Eternity build scheduled for December with tube rolling add-on. He will have lots of information in this thread!


----------



## OctavianH

SonicTrance said:


> Just to let you know there’s another Eternity build scheduled for December with tube rolling add-on. He will have lots of information in this thread!


It will have same manual bias settings and so on? Or it will go for automatic bias?


----------



## SonicTrance

OctavianH said:


> It will have same manual bias settings and so on? Or it will go for automatic bias?


It wouldn’t be an Eternity if going with cathode bias. Grid bias all the way!


----------



## OctavianH (Aug 5, 2022)

A glass of dry red wine always goes well with Eternity. This time we have to decypher the latest Soulfly album, Totem. Friday Wineday!






While I usually prefer 6SL7 with 807 I try now to experiment with some 6C4. It is soft, but I want to see if I can get comfortable with this.

Later edit: I wasn't happy, soft. RCA 807 + Sylvania 6SL7, my 90 EUR combo fixed all. That's what I paid for all and are perfect.


----------



## OctavianH

Motto of today: *Almost 3 weeks without Eternity... are an eternity*. After a longer break, when I had all my filtering and power conditioning off, I find the amplifier sounding spectacular. Might be my brain, might be something else. I will never know, but I will investigate in the future what happens if from time to time I stop these filters.


----------



## OctavianH

While I am not experimenting anything anymore, I still enjoy Eternity every day. Being so flexible it allows me to find more and more combinations. For example yesterday I tried some GEC 12E1 with Fivre 76 but because of the low gain of 76 (a little bit lower than 6C5) I had to push the volume close to 75%. Yep, it is more clear to me that there is a "minimum sum of gains" which is a decent value for me to enjoy a combo. There was no problem to listen at 75% of the volume knob, but I had the feeling that the sound was a little bit forced. I used the gain switch and with the "high" position I lowered volume around 50%. I felt a little bit more relaxed sound, an idea more bass, but still it was not an optimal sound for my taste. Going to GEC E3375 (british EL38 prototype) things went a lot in my expected direction.





While I have not bought a tube in months, my focus is now into a different area. To find out which gains are somehow optimal for my taste, maybe to experiment more with things I never tried during my journey and so on. Because, as we all know, we have listening phases and if you buy a tube in that period of time, you will, most probably, combine it with what you recently liked more. Well, now we try what we forgot to try and the fun fact is that I have no favourite combo, I oscillate between several nice ones and more than this, I am still discovering new things. That's a good point for me.

Thinking about a future amp and what I would like to have, well, my initial idea of a balanced Citadel involves quads of outputs and pairs of inputs and I have become very comfortable with my single double triode on input. I have some quads, but definitely only a few pairs compared to the rest of my collection. Same for the input matched pairs. And I do not want to renounce on the manual grid bias, I like it, I feel I have more control and all sounds tighter and more predictible. So I still want to remain on manual bias, I want to use these gyrator/CCS and I am not really sure how much I will be able to roll on that one. 

If I'll ever decide to move from this amp I'll add for sure:
- 6.3/12.6 on both stages (maybe in this way I'll listen until I die to GU50 which many praise and maybe I'll try some 12SN7/12SL7, many of my 12A*7 should also work)
- I'll ask for a bigger trimmer on input (at first I decided to avoid going for output designed tubes on input, but I quite miss to try 6V6 and EL32 on input because they were very nice on Elise and might be interesting here)
- maybe I'll go for both SS and rectifier, even if I am reluctant in this area, we open another Pandora box here
- and yes I'll have to choose a bigger chasis (at first I wanted a small amplifier, but with 12/6 stuff I guess I'll have to switch to some Telemachus chasis)

Thoughts and thoughs, I have time a few years to decide. Well, a good time for a cold beer.


----------



## Isaacc7

OctavianH said:


> While I am not experimenting anything anymore, I still enjoy Eternity every day. Being so flexible it allows me to find more and more combinations. For example yesterday I tried some GEC 12E1 with Fivre 76 but because of the low gain of 76 (a little bit lower than 6C5) I had to push the volume close to 75%. Yep, it is more clear to me that there is a "minimum sum of gains" which is a decent value for me to enjoy a combo. There was no problem to listen at 75% of the volume knob, but I had the feeling that the sound was a little bit forced. I used the gain switch and with the "high" position I lowered volume around 50%. I felt a little bit more relaxed sound, an idea more bass, but still it was not an optimal sound for my taste. Going to GEC E3375 (british EL38 prototype) things went a lot in my expected direction.
> 
> 
> 
> ...


In a fit of “why not?” I ordered my amp with 6v/12v option on both input and output. Thinking about it a little bit, the gu50 many be the only 12v output tube that is either only available in that voltage or Substantially cheaper. Most 12v output tubes have 6v versions. Unlike the input tubes, the 6v versions are usually pretty cheap. The only 12v output tubes I can think of are 12v6, 12aq5, 1625, GU50, TT22, N34, and a variety of TV tubes like the 12av5, 12dq6, etc. With the exception of thje TT22 , possibly the N34, and the aforementioned GU50, all of the equivalent 6v tubes are fairly inexpensive. The N34 is less than the KT61 but not by that much especially when you take into account the necessary adapters. The thing is, you are only supposed to run the KT61 with auto bias and my amp is manual, Boo! On top of that, all of the more desirable (European) versions of the 6v6, 807, and 6aq5 weren’t made in 12v. Not sure if spending the money on 12v outputs is worth it. If you do want to use odd output tubes you can also use an external power supply for the heaters. That can be used with multiple amps and potentially multiple heater voltages. I bought a variable voltage supply to use 12v input tubes on my current amp but have also used it to use an 11v tube. I might try some 4v output tubes in the future. 

12v for the input tubes is a no brainer for me. I have done very well with 12sn7 and 12j5 and there are bound to be other ones I haven’t stumbled across yet.  It cost me a bit to get both my preamp and amp to use 12v input tubes but the price of the better 6sn7 tubes means it has paid off.


----------



## OctavianH

Nothing beats tube rolling except lamp rolling. Yeap, you heard me right. I bought a new desk lamp for my office setup. And we have a bigger and nicer warm light. So now my beer looks better in pictures! Good catch. Thanks IKEA.





On the other hand I have not changed the tubes for almost one month. And this says something. But exchanging lamps made me modify the position of the TT2 + M Scaler combo on the desk. And you know what is funny, when I put them closer to my monitor I hear some missing detail in the higher frequency area. when I move it closer to the wall all is back. Crazy? I am crazy, most probably. I'll stop here because now the Noise Denying Inquisition will come after me.

Back to my new Ozzy album. Found it yesterday and it is incredible. Cheers.


----------



## triod750

Cheers/skål/skaal.


----------



## OctavianH

triod750 said:


> Cheers/skål/skaal.


This lamp was called SKURUP.





Hmmm. :|


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## triod750

Skurup is a place in southern Sweden. I can't understand that translation. It's totally without relevance. As proper as translating Brasov to person.


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## OctavianH (Sep 9, 2022)

triod750 said:


> Skurup is a place in southern Sweden. I can't understand that translation. It's totally without relevance. As proper as translating Brasov to person.


Found the problem and it was me. Anyway "scurf" does not say more to me. LOL.






This lamp is like a sun in my room, light everywhere. So now I see every piece of dust on Eternity. Damn.


----------



## triod750

Skurup will take you through the winter like a breeze...


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## triod750

Scurf????

Not even close. If you want to translate Skurup to english it becomes skurup and Stockholm becomes stockholm. Träd becomes tree. Sol becomes sun. We take the rest some other time. (Ljud becomes sound).


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## jonathan c

OctavianH said:


> This lamp was called SKURUP.


Stock Keeping Unit   Resale Under Pressure 🤣🤣🤣🤣


----------



## OctavianH

jonathan c said:


> Stock Keeping Unit   Resale Under Pressure 🤣🤣🤣🤣


I'll suggest them to call it Slayer. We all know it is better.


----------



## triod750

Can't hear you, Sunshine...


----------



## triod750

LED lamps are supposed to give electrical disturbance...


----------



## OctavianH

triod750 said:


> LED lamps are supposed to give electrical disturbance...


But for sure they make the tubes look nicer, at least this new one which is placing light from the front and I am able to show all 5 tubes in detail.





This combo sits there for around one month and I have no energy of changing it. Let's hope that now, after summer has passed, I'll have more energy to experiment. I still have some novals I never tried or not tried enough. So there is more to go. More than this, I never got to try 6BG6 and 6AR6 even if I already have the adapters. So we still have stuff to do at around 17 months since I've received Eternity.


----------



## Isaacc7

OctavianH said:


> But for sure they make the tubes look nicer, at least this new one which is placing light from the front and I am able to show all 5 tubes in detail.
> 
> 
> 
> This combo sits there for around one month and I have no energy of changing it. Let's hope that now, after summer has passed, I'll have more energy to experiment. I still have some novals I never tried or not tried enough. So there is more to go. More than this, I never got to try 6BG6 and 6AR6 even if I already have the adapters. So we still have stuff to do at around 17 months since I've received Eternity.


When you dive into the world of 6bg6 I recommend looking at the 6bg6ga, the newer ones. As far as I can tell, the 6bg6g tubes are essentially the same as the 807 tubes while the GA tubes have a good chance of being a newer 6l6 variant like the 6l6gc or 7581a.


----------



## OctavianH

Isaacc7 said:


> When you dive into the world of 6bg6 I recommend looking at the 6bg6ga, the newer ones. As far as I can tell, the 6bg6g tubes are essentially the same as the 807 tubes while the GA tubes have a good chance of being a newer 6l6 variant like the 6l6gc or 7581a.


I wonder if 6BG6 or 6BG6GA are more of interest to me, honestly 807 sound killer here while a pair of 6L6 and another pair of 7581A are sitting in a box. I know that many of you consider 807 the 6L6 of the poor and that they are direct related, but I could not find yet a preference for the 6L6 over 807. It might be that the manufacturers of the pairs I have listened were the reason, could be. I do not have a 6L6 and 807 from the same manufacturer to compare.


----------



## Isaacc7

OctavianH said:


> I wonder if 6BG6 or 6BG6GA are more of interest to me, honestly 807 sound killer here while a pair of 6L6 and another pair of 7581A are sitting in a box. I know that many of you consider 807 the 6L6 of the poor and that they are direct related, but I could not find yet a preference for the 6L6 over 807. It might be that the manufacturers of the pairs I have listened were the reason, could be. I do not have a 6L6 and 807 from the same manufacturer to compare.


I’ve been looking at the 6bg6 and 807 a little more closely. Both the 807 and 6bg6g are essentially the 6l6gb of the manufacturer. As far as I can tell that holds true across both tube types for the most part. Some manufacturers of the 6bg6, GE and Sylvania/Philips in particular, ended up swapping 6l6gc parts in the 6bg6ga. Well, I know that Sylvania/Philips did, looks like they are actually 7027a internals which are the most powerful they ever made and are well loved by guitarists. The GE is a little more complicated. First, I don’t have any of them in my hands to really confirm this. The second thing is that GE did make some 6bg6ga with what looks like their 6l6gc (also well regarded) but with black plates instead of grey.  I have seen at least two versions of the GE, one with the big plates as I mentioned and one with smaller. I think the smaller are the same as the 6l6gb. In any case, I think they sound great and are super cheap. 

If the 6bg6g and 807 are basically the same which adapter should you buy? Both have their upsides and its why I have both. One of the big things about the 807 is that European manufacturers made them. So if you want Mullard, GEC, Mazda, etc. you want the 807. There are two reasons to get 6bg6 adapters. First, even though the 6bg6g and 807 American tubes look  to be essentially the same tube, the 6bg6g are inevitably less expensive. The other reason is that you can get the equivalent of American 6l6gc tubes cheaply, Sylvania definitely and GE probably. Sylvania/Philips did the same thing with the 807 but those are much more difficult to find and are noticeably more expensive. Unfortunately it doesn’t look like RCA did. I really want to hear RCA blackplate 6l6gc but I don’t want to pay the premium. Oh well, I guess I’ll leave them to the guitarists.


----------



## OctavianH

Isaacc7 said:


> If the 6bg6g and 807 are basically the same which adapter should you buy? Both have their upsides and its why I have both. One of the big things about the 807 is that European manufacturers made them. So if you want Mullard, GEC, Mazda, etc. you want the 807.


I am evaluating a tube type based on what manufacturers produced it, price and electrical characteristics (up to the point I understand them). In my case 807 is a much better deal than 6BG6, which are not easy to find in Europe anyway. I have RCA/Mullard/GEC (a variation, not 807 but works with same adapter and biases the same, you know it, ATS25). For Sylvania I have 5933 which are very nice for the price. And if you really want to optimize as much as you can the price/performance ratio you can try some russian G-807. Very good for the price, a little bit more sterile than others but still, same type of sound.

At the moment I am in phase 3 of understanding Eternity. Phase 1 was: roll all with all to have an idea about each one. Phase 2 was: find some favourite combinations or at least some basic rules to improve synergy when combining (gain, type x with type y, manufacturer x with manufacturer y, stuff like that). Now I am in Phase 3: to use for weeks a combo which remained in my mind in Phase 1 and 2 and understand more about the small details which make them shine.

Today I try GEC ATS25 with Telefunken ECC801S and I really like what I hear. While I know that no one can easily predict how a combination will sound, there are some "guidelines" which can help you obtain synergy and desired effect with less tries. That's what I tried to find in Phase 2. Now, in Phase 3 we go for the final assessment.





PS. Paint on my tubes starts to wear off, I have to make some pictures or understand more about internal construction before I will not be able to identify them anymore, if  I put them in the same drawer without a properly marked box. LOL


----------



## Isaacc7

OctavianH said:


> I am evaluating a tube type based on what manufacturers produced it, price and electrical characteristics (up to the point I understand them). In my case 807 is a much better deal than 6BG6, which are not easy to find in Europe anyway. I have RCA/Mullard/GEC (a variation, not 807 but works with same adapter and biases the same, you know it, ATS25). For Sylvania I have 5933 which are very nice for the price. And if you really want to optimize as much as you can the price/performance ratio you can try some russian G-807. Very good for the price, a little bit more sterile than others but still, same type of sound.
> 
> At the moment I am in phase 3 of understanding Eternity. Phase 1 was: roll all with all to have an idea about each one. Phase 2 was: find some favourite combinations or at least some basic rules to improve synergy when combining (gain, type x with type y, manufacturer x with manufacturer y, stuff like that). Now I am in Phase 3: to use for weeks a combo which remained in my mind in Phase 1 and 2 and understand more about the small details which make them shine.
> 
> ...


I’ve been thinking about the 6bg6 vs 807 thing a bit more. The general consensus is that they were initially the same tube but with a different pin out. I’m not so sure anymore. Early RCA and the 6bg6 look the same Most 807 I have seen has a prominent part just below the bottom mica. Usually a curved piece of metal either shiny or black though I have seen some solid black blocks on some of them.  None of the 6bg6 I have seen have it. Now maybe that doesn’t have anything to do with how it performs with audio (or TVs I guess) but it does mean the tubes were made differently. I only have a few kinds of 6bg6 tubes but don’t have the same manufacturer in 807 to put it to the test. I’ll get around to testing that at some point. 

Anyway, my long, rambling point is that by the book these tube types should be “the same” but we aren’t using them as horizontal deflection amplifiers or as RF finals so I think all bets are off 

The 6bg6 was a North America only thing I think so you won’t get the European brands with it. I do think that the USA made some legendary output tubes and the 6l6 family is example number one. Like I’ve mentioned before, the 6bg6ga did see manufacturers get a little more creative towards the end of the tube age. You can find updated internals in them but the 807 mostly stayed the same, probably because there were so many of them on the surplus market it wasn’t worth messing with.


----------



## Isaacc7

OctavianH said:


> I am evaluating a tube type based on what manufacturers produced it, price and electrical characteristics (up to the point I understand them). In my case 807 is a much better deal than 6BG6, which are not easy to find in Europe anyway. I have RCA/Mullard/GEC (a variation, not 807 but works with same adapter and biases the same, you know it, ATS25). For Sylvania I have 5933 which are very nice for the price. And if you really want to optimize as much as you can the price/performance ratio you can try some russian G-807. Very good for the price, a little bit more sterile than others but still, same type of sound.
> 
> At the moment I am in phase 3 of understanding Eternity. Phase 1 was: roll all with all to have an idea about each one. Phase 2 was: find some favourite combinations or at least some basic rules to improve synergy when combining (gain, type x with type y, manufacturer x with manufacturer y, stuff like that). Now I am in Phase 3: to use for weeks a combo which remained in my mind in Phase 1 and 2 and understand more about the small details which make them shine.
> 
> ...


Did you see this article from the Valve Museum about the 807? http://www.r-type.org/addtext/add029.htm

Basically it says that the Brits had a very difficult time making a tube as good as the RCA 807. Their attempts were all over the place and they ended up creating a variety of tube designations to signify how hard they could be run and which equipment could use them. Apparently audio use was fine but RF was an issue as they tended to be run much harder. 

The “Cossor” tubes that I love so much were actually made by Edwinison-Mazda and are the second ones linked in the last paragraph as a VT60. I have tubes with exactly the same construction marked as VT60, 807, and ATS25.


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## OctavianH (Sep 17, 2022)

Isaacc7 said:


> Did you see this article from the Valve Museum about the 807? http://www.r-type.org/addtext/add029.htm
> 
> Basically it says that the Brits had a very difficult time making a tube as good as the RCA 807. Their attempts were all over the place and they ended up creating a variety of tube designations to signify how hard they could be run and which equipment could use them. Apparently audio use was fine but RF was an issue as they tended to be run much harder.
> 
> The “Cossor” tubes that I love so much were actually made by Edwinison-Mazda and are the second ones linked in the last paragraph as a VT60. I have tubes with exactly the same construction marked as VT60, 807, and ATS25.


I've seen it and I've seen also many other comments on different threads. I doubt that what we hear when using them is related to what they called in those times "high performance valve" or "dubious". These were designed for a different usage than ours and were also categorized by different criterion that what we now need. Now I keep 807 at 200V plate biased to provide 20mA which is a joke compared to maximum ratings it has to provide. So many of the remarks relating optimizations I doubt are ever relevant to our amps.

PS. I've posted this link several pages ago, page 8 & 9 is related to 807, "The Little Magician".


----------



## Isaacc7

OctavianH said:


> I've seen it and I've seen also many other comments on different threads. I doubt that what we hear when using them is related to what they called in those times "high performance valve" or "dubious". These were designed for a different usage than ours and were also categorized by different criterion that what we now need. Now I keep 807 at 200V plate biased to provide 20mA which is a joke compared to maximum ratings it has to provide. So many of the remarks relating optimizations I doubt are ever relevant to our amps.
> 
> PS. I've posted this link several pages ago, page 8 & 9 is related to 807, "The Little Magician".


Heh, I think I posted it in the pentode thread. Yeah, 200v and 20mA is just loafing for them.


----------



## OctavianH

Isaacc7 said:


> Heh, I think I posted it in the pentode thread. Yeah, 200v and 20mA is just loafing for them.


Yep so most probably the "dubious" ones are sounding exactly the same as the rest of them. LOL


----------



## DecentLevi (Sep 21, 2022)

It's nice to see the Ultrasonic tube rolling thread is still around. A lot has changed since my last time posting here.

I've recently had the chance to try my first 6SL7 tubes on my custom Infinity-Odyssey amp I call Finyssey. Unfortunately for me that meant a much louder hum.
_(note: this relates to my 15 watt hefty Sowter transformers that are said to have a noisefloor, especially with sensitive headphones. I have spent months and all known and some unknown tricks to remedy it, this is not caused from me)._
Realizing that the 6SL7 has a gain factor of 70 as compared to 20 with 6SN7, no wonder. While I wasn't expecting a correlation between hum and input tube gain factor, this may actually turn into a good thing!

Now I believe my solution to finally remedy this would be to find input tubes with _lower _gain! I would be interested to know if any of you can recommend a tube that is compatible with 6SN7-class (or 6J5) either by drop-in replacement or via adapter that has less than 20 gain, and sounds good? Gain is shown as µ = (x) on the tube's datasheet. Ideally somewhere around 6-15 gain factor.
This may be a question that @mordy @gibosi @MIKELAP would know.


----------



## mordy

DecentLevi said:


> It's nice to see the Ultrasonic tube rolling thread is still around. A lot has changed since my last time posting here.
> 
> I've recently had the chance to try my first 6SL7 tubes on my custom Infinity-Odyssey amp I call Finyssey. Unfortunately for me that meant a much louder hum.
> _(note: this relates to my 15 watt hefty Sowter transformers that are said to have a noisefloor, especially with sensitive headphones. I have spent months and all known and some unknown tricks to remedy it, this is not caused from me)._
> ...


How much current can the driver socket handle in your amp?


----------



## gibosi (Sep 21, 2022)

DecentLevi said:


> It's nice to see the Ultrasonic tube rolling thread is still around. A lot has changed since my last time posting here.
> 
> I've recently had the chance to try my first 6SL7 tubes on my custom Infinity-Odyssey amp I call Finyssey. Unfortunately for me that meant a much louder hum.
> _(note: this relates to my 15 watt hefty Sowter transformers that are said to have a noisefloor, especially with sensitive headphones. I have spent months and all known and some unknown tricks to remedy it, this is not caused from me)._
> ...



As per Mordy's comment above, if your amp can handle drivers drawing as much as 1.5A, these come to mind. If I think of others, will update this post.

5687        mu16     .9A
6BX7GT  mu10    1.5A
6BL7       mu15    1.5A
BL63       mu12    1.3A


----------



## gibosi

gibosi said:


> As per Mordy's comment above, if your amp can handle drivers drawing as much as 1.5A, these come to mind. If I think of others, will update this post.
> 
> 5687        mu16     .9A
> 6BX7GT  mu10    1.5A
> ...



Running a pair of single triodes as drivers, for example, a pair of Type 76 with a mu of 13.8, might be worth considering....


----------



## Isaacc7

gibosi said:


> Running a pair of single triodes as drivers, for example, a pair of Type 76 with a mu of 13.8, might be worth considering....


The 31 tube uses the same pin out so you could use them as well as the 76 with the same adapters. Both the 76 and 31 also have the benefit of being pretty cheap as well.


----------



## DecentLevi (Sep 21, 2022)

mordy said:


> How much current can the driver socket handle in your amp?


@SonicTrance It looks like you said input tubes can handle 3-4mA of plate current. Unless I'm mistaken 6SN7's are 0.6mA so I could theoretically go up to 6.5x higher plate voltage, and the likes of 6BL7 with 1.5mA would be good. I know the voltage of my socket is 6.3. Incidentally I already have a handful of good 6BL7's laying around I could try. Looks like the pinout is the same as 6SN7's and it's pentode instead of dual triode.

And once more please clarify what is the formula to calculate the recommended cathode bias setting for a tube based on the datasheet?
(my amp uses manual grid bias by multiturn knob measured with Volt-o-meter)
I have what you told me that to find the operating points for correct settings calculate the max plate dissipation by multiplying anode voltage times current and you gave me a formula 180V, times abode current, 4mA. 180*0,004=0,72W. But I'm really not sure which sections to look for on the tube datasheet since they use special symbols for those values? Maybe you can give a practical example with the values of 6BL7. Is 0.72W the min. value?


----------



## mordy

DecentLevi said:


> @SonicTrance It looks like you said input tubes can handle 3-4mA of plate current. Unless I'm mistaken 6SN7's are 0.6mA so I could theoretically go up to 6.5x higher plate voltage, and the likes of 6BL7 with 1.5mA would be good. I know the voltage of my socket is 6.3. Incidentally I already have a handful of good 6BL7's laying around I could try. Looks like the pinout is the same as 6SN7's and it's pentode instead of dual triode.
> 
> And once more please clarify what is the formula to calculate the recommended cathode bias setting for a tube based on the datasheet?
> (my amp uses manual grid bias by multiturn knob measured with Volt-o-meter)
> I have what you told me that to find the operating points for correct settings calculate the max plate dissipation by multiplying anode voltage times current and you gave me a formula 180V, times abode current, 4mA. 180*0,004=0,72W. But I'm really not sure which sections to look for on the tube datasheet since they use special symbols for those values? Maybe you can give a practical example with the values of 6BL7. Is 0.72W the min. value?


The 6BL7 is a dual triode with the same pinout as 6SN7 and it draws 1.5A.


----------



## DecentLevi

I'll wait for Tomas to chime in. If the 6SN7 is 600mA then it might mean my amp handles 300-400mA of current for input tubes, otherwise that would make it 0.003-0.004mA.


----------



## JazzVinyl (Sep 22, 2022)

@DecentLevi - congrats on your new custom amp!

Tubes use two voltage circuits with different voltage/current amperage needs....let's take a look at the 6SN7 data for example:

The heater circuit uses 6.3 volts (AC or DC) @ 0.6 amps.  That is a little more than a 1/2 of one full amp of current.  In Milliamps 0.6 amp is expressed as 600ma (1000ma = 1 amp)

https://www.convertunits.com/from/milliamps/to/amps

The Plate voltage for a 6SN7 says 250 volts of DC @ 20ma (milliamps) which is 0.02 amps.


====
The Heaters use low voltage but at much higher current to make the heaters warm up (which makes the electrons flow inside the tube).

The Plates (actual audio signal processing) use a much higher voltage,  but with a really minuscule amount of current behind that voltage.

Hope that helps...


----------



## DecentLevi

Thanks for your help everybody! Gibosi and Mordy for recommending lower gain tube types, and JV for his explanation. 

I would like to try some of the recommended input tubes, but first @SonicTrance or maybe even @OctavianH please help clarify how I calculate the recommended cathode bias settings? My input section is manual bias adjustment via multi-turn trimmer. As I understand, I would multiply the anode (or plate) voltage by the current. Per the above example I got a value of 0.72W and it would be 1W for 6SN7. But what do I then do with that number to get the estimated bias value setting?

Also how much current can the input sockets of my amp handle?


----------



## OctavianH

DecentLevi said:


> I would like to try some of the recommended input tubes, but first @SonicTrance or maybe even @OctavianH please help clarify how I calculate the recommended cathode bias settings? My input section is manual bias adjustment via multi-turn trimmer. As I understand, I would multiply the anode (or plate) voltage by the current. Per the above example I got a value of 0.72W and it would be 1W for 6SN7. But what do I then do with that number to get the estimated bias value setting?


I am not sure if your input stage is biased in the same way as mine. But in my case, I calculate the bias in the following way:
- I know the optimal operating point of the input stage: Vplate = 180V and Iplate = 4mA (the audio signal) (however, Tomas told me 3-5mA are fine)
- I know that for example 6SN7 has 2.5W plate dissipation (from the datasheet)
- I look at the triode graphs from the datasheet and calculate which value for Grid I need to select with the multiturn trimmer to obtain 4mA at 180V.

For example:






In this 6SN7 graph showing Plate current/volts I make an intersection of 4mA (current, vertical axe) to 180V (voltage, horizontal axe) and I see that the point of intersection is between the -6V and -8V curvers almost at the middle. These values are the optimal operating point mentioned above.

- after determining the grid voltage value as above, I start the amplifier without any tube inserted
- I set on the amp with the voltmeter a grid voltage of -7V and then I stop it (I expect this -7V will make my 6SN7 reach 4mA when inserted)
- I wait for 5 minutes for the output capacitors to discharge and then insert the tubes and start the amplifier
- the mA meter for input stage should display a value close to 4mA (if not we can fine tune the grid bias via multiturn trimmer to reach it)

Basically after every tube change or grid adjustment I wait around 5 minutes. 

Because 6SL7 has 1W plate dissipation (much lower than 6SN7) I use it at 3mA to keep it cool enough (Tomas advised me to use 6SL7 and 12AX7 at 3mA instead of 4mA because of the plate dissipation, so in their case the operating point used to calculate grid bias is 180V / 3mA, procedure remains the same as above). 

That's all I do. I do not know anything about other limitations, and on my amp the heater winding is up to 14A so I doubt I'll ever reach that value regardless of the tube types I use. As I said, this is valid for Eternity. On F.A, amps there is a limitation for sum of heaters around 7A (this is why they always calculate to remain under the value), here with 14A I do not really care about it.


----------



## SonicTrance

@OctavianH Thanks for the explanation! Levi's input stage is configured exactly like yours so same applies to him!

@DecentLevi Please, have a look at the first page in our, very long, pm thread. Where I explain this and even drew load lines with operating points on 8 different tubes! Granted that was output tubes but you need to learn how to read datasheets and setup your amp properly to a new tube. That is crucial!

Available heater current for your amp, Levi:
Power tube sockets (KT88 etc.): 5.4A
Dual triode socket (6SN7 etc.): 2.5A
Single triode sockets (6J5 etc.): 3.8A

I had three different 6.3V windings at hand so instead of paralleling them all I did it like that.


----------



## DecentLevi

Thanks again guys. I've now got a grasp on how to figure out the how to bias a tube for my amp (4mA 180v) based on the datasheet curves. I was able to find a close value to what was recommended by Tomas for 6SN7 and VT-96 (6N7), but when it came to 6BL7 the closest bias value for my amp I could get was around -12.5.V, is that about correct? The 6BL7 has a peak cathode current of around 210mA so it seems weird that it would only use 4mA on my amp so I hope that doesn't cause any issues. In comparison to 6SN7 with a peak cathode current is showing as 7mA but the curves show values up to about 16mA.

@OctavianH 
would you also tell me how to calculate the input tube bias setting for tubes that don't show the curves? This would also give a more precise value.

For output tubes, since mine is auto bias, looks like I just need to make sure the datasheet curves show an intersection between 200V plate voltage (Va) and 50mA plate current, and that the current for both tubes does not exceed 5.4A.


----------



## SonicTrance

DecentLevi said:


> For output tubes, since mine is auto bias, looks like I just need to make sure the datasheet curves show an intersection between 200V plate voltage (Va) and 50mA plate current, and that the current for both tubes does not exceed 5.4A.


Your output stage is not biased at 200V 50mA anymore since the rebuild, remember? Like you say it's now cathode biased with anode voltage 400V!


----------



## Isaacc7

Boys, my fever may have broken. Since the US dollar is doing so well against the Pound I figured I'd check out Billington. I can't find anything I want to order! Have I satiated my tube hunger? Not quite, but the ones I am still interested in getting are all available  domestically. I'm simply not going to buy the expensive tubes I don't have like original kt66, kt77, kt88, etc. It doesn't help that I need 4 of them at a time. I feel like a weight has been lifted from me lol.


----------



## OctavianH

DecentLevi said:


> Thanks again guys. I've now got a grasp on how to figure out the how to bias a tube for my amp (4mA 180v) based on the datasheet curves. I was able to find a close value to what was recommended by Tomas for 6SN7 and VT-96 (6N7), but when it came to 6BL7 the closest bias value for my amp I could get was around -12.5.V, is that about correct?



In my opinion you are OK with -12.5V. We are using these tubes at much below average characteristics.








DecentLevi said:


> @OctavianH
> would you also tell me how to calculate the input tube bias setting for tubes that don't show the curves? This would also give a more precise value.



The only way is to determine it via curve tracer or tube tester. You measure with grid set to much more than what you expect and lower grid until you reach 4mA. After that you set the same value on the amplifier. Or you find a friend to measure/determine it for you. If there are other ways, I have no idea. I measure here for those.


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## OctavianH (Sep 24, 2022)

One more thing: the reason you need such high negative voltage on 6BL7 compared to 6SL7 for example is because you try to use tubes designed for output in input stage. An input tube is high gain and low plate current, output tube is low gain and high plate current. Heater current does not have anything to do  here, the lower the better and I think it matters only as a metric of efficiency. Another consequence is that using low gain tubes on input you will lower the overall gain of the amplifier.

Later edit: It is always better to set a bigger value on grid voltage than what you determine, in this case you ensure a lower plate current if the tube is "too strong". For example instead of that -12.5V I'll try first with -13V and then fine tune via trimmer.


----------



## Isaacc7

Isaacc7 said:


> Boys, my fever may have broken. Since the US dollar is doing so well against the Pound I figured I'd check out Billington. I can't find anything I want to order! Have I satiated my tube hunger? Not quite, but the ones I am still interested in getting are all available  domestically. I'm simply not going to buy the expensive tubes I don't have like original kt66, kt77, kt88, etc. It doesn't help that I need 4 of them at a time. I feel like a weight has been lifted from me lol.


Err... Nevermind lol. Should have seen that coming. Thought of a few tubes that would be nice to have. If he has them in stock I'll do a last Billingham order after all.


----------



## DecentLevi

OctavianH said:


> One more thing: the reason you need such high negative voltage on 6BL7 compared to 6SL7 for example is because you try to use tubes designed for output in input stage. An input tube is high gain and low plate current, output tube is low gain and high plate current. Heater current does not have anything to do  here, the lower the better and I think it matters only as a metric of efficiency. Another consequence is that using low gain tubes on input you will lower the overall gain of the amplifier.
> 
> Later edit: It is always better to set a bigger value on grid voltage than what you determine, in this case you ensure a lower plate current if the tube is "too strong". For example instead of that -12.5V I'll try first with -13V and then fine tune via trimmer.


The lowest my multi-turn goes is -10.6v, just measured it. I think I'll try it that way because I usually have to increase the amount again after turning it on anyway.


----------



## DecentLevi

Luckily there were no issues with 6BL7 at -10.6v bias. I actually had to turn and turn a few times up until about -8.5v in order for the mA meters to barely reach about 3mA. I could've continued turning up until about 4-5mA but I hope that won't be pushing it? The sound was actually quite great, and not quite as bright which was welcome. Background was a bit quieter than the 6SN7 I compared it to, but not by much. Looks like I'll be trying the 6BL7 with more output combos. But man these sure get HOT hot!


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## mordy

Isaacc7 said:


> Err... Nevermind lol. Should have seen that coming. Thought of a few tubes that would be nice to have. If he has them in stock I'll do a last Billingham order after all.


IT NEVER ENDS!


----------



## Isaacc7

mordy said:


> IT NEVER ENDS!


I know, laugh at me. I do however see an end in sight for me. I have so many tubes now. Most of them unloved, forgotten types by the mainstream. The only way I see myself going beyond my plans is if I purchase an amp that needs different kinds of tubes altogether. Doubt I’d do the triode thing unless I came into a lot of money. I could imagine an amp that uses lower voltage pentodes, like 250v and lower. Probably parallel single ended. Or an amp that can use sweep tubes with a low screen voltage, also probably single ended. Not that I’ve thought about these possibilities at all…


----------



## mordy

Isaacc7 said:


> I know, laugh at me. I do however see an end in sight for me. I have so many tubes now. Most of them unloved, forgotten types by the mainstream. The only way I see myself going beyond my plans is if I purchase an amp that needs different kinds of tubes altogether. Doubt I’d do the triode thing unless I came into a lot of money. I could imagine an amp that uses lower voltage pentodes, like 250v and lower. Probably parallel single ended. Or an amp that can use sweep tubes with a low screen voltage, also probably single ended. Not that I’ve thought about these possibilities at all…


Nobody laughs at you for buying more tubes - we are all in the same boat! I am trying to restrict myself by setting a dollar limit on how much I can spend per tube, but it doesn't always work lol...
Re forgotten and unloved tubes - you never know when someone will come up with a good sounding combination that uses just such tubes!
You may want to ask a custom amp builder about the feasibility of using different kinds of tubes.


----------



## Isaacc7

mordy said:


> Nobody laughs at you for buying more tubes - we are all in the same boat! I am trying to restrict myself by setting a dollar limit on how much I can spend per tube, but it doesn't always work lol...
> Re forgotten and unloved tubes - you never know when someone will come up with a good sounding combination that uses just such tubes!
> You may want to ask a custom amp builder about the feasibility of using different kinds of tubes.


I've got one on the way from Ultrasonic Studios that allows me to use any number of tubes in the "normal" range. So things like 6sn7 and other twin triodes and 6v6/6l6/el34/kt88 and everything in-between on the outputs. It's a push pull amp with variable plate voltage and manual bias on the output tubes. Oh, and I can use either 6v or 12v on both output and input tubes. As it is I already plan on using some oddball tubes like the GU50, 12av6, and maybe even 2e26. I already have adapters for 6f8g, 7n7, 7c5, 807, 6bg6, el38, and 6aq5 to octal sockets. If I had another tube amp made it would be for tubes much further afield than even those! 4v British tubes, sweep tubes, etc. If I hit the lottery I'm sure I would order some crazy single ended triode amp using Eimac or other high voltage stuff lol.


----------



## mordy

Isaacc7 said:


> I've got one on the way from Ultrasonic Studios that allows me to use any number of tubes in the "normal" range. So things like 6sn7 and other twin triodes and 6v6/6l6/el34/kt88 and everything in-between on the outputs. It's a push pull amp with variable plate voltage and manual bias on the output tubes. Oh, and I can use either 6v or 12v on both output and input tubes. As it is I already plan on using some oddball tubes like the GU50, 12av6, and maybe even 2e26. I already have adapters for 6f8g, 7n7, 7c5, 807, 6bg6, el38, and 6aq5 to octal sockets. If I had another tube amp made it would be for tubes much further afield than even those! 4v British tubes, sweep tubes, etc. If I hit the lottery I'm sure I would order some crazy single ended triode amp using Eimac or other high voltage stuff lol.


I always wanted to try the GU50 Russian tubes which are modeled on the Telefunken LS50 tubes.
I think that LordGwyn tried some early 4V tubes in the past.


----------



## Isaacc7

mordy said:


> I always wanted to try the GU50 Russian tubes which are modeled on the Telefunken LS50 tubes.
> I think that LordGwyn tried some early 4V tubes in the past.


The GU50 has to be the ugliest tube going. They're so cheap and they have a great reputation. I couldn't resist! If your amp can provide 12v for the heaters you can use an external power supply just for the heaters.


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## OctavianH (Sep 25, 2022)

DecentLevi said:


> Luckily there were no issues with 6BL7 at -10.6v bias.


You were lucky but do not try this too often. Your 6BL7 was heavily used and this is why you were able to use it at around 70% of the datasheet specs. But this is not always the case. For short periods of time I guess it is fine (you stop the amp if you see that the current raises too much and that's it) but look at this 6SL7 graph. We would need around -0.7V for 3mA. Right?





Well, check one of my Fivre when measured. I have here 2 situations I want to show you. First, the tube is above 100% (according to datasheet) because it has 3mA at around -1V (30% above?) and it is also unbalanced internally. When I set on my amp -1V grid bias one of the triodes goes to 2.6ma while the other is around 3.7mA.





And you can see that for around -0.1V I have a variation of 0.2mA. This delta parameter can vary and I know it has a name, but I am a noob and forgot it. Doesn't matter, numbers speak for themselves. In short words, what I am trying to say is, never think "has to work with +2V of bias because the trimmer does not go so low or it worked once". And always check both channels, this Fivre on one channel might have 4mA and on the other 5.1ma but there are worse scenarios.

And another thing that I have learned during time while measuring these, is that it is no rule that a tube which measured 100% at a specific seller (if he tells the truth LOL) will be at 100% in our amps. Because they measure in specific conditions, taken from datasheets and measurement's device manual while we use them in totally different conditions. We would expect a linear variation with plate voltage? Well, I had surprises. Tube measured perfectly according to the datasheet was not as expected at 180V and so on. And this discussion might go more and more into what means 100%, what means matched pair and so on. For me nothing, except 2-3 persons I trust and from which I buy with confidence, the rest we measure and put in a box if does not work as expected or sell to people with automatic bias. I bought tubes measuring 70% from Langrex as "NOS", and electrically matched in tolerance of 15% and was told it's fine.

Later edit: For output tubes I use exactly the same method to determine the grid bias, I just look at "Triode connection graph" because outputs are triode strapped on the amp. So same stuff, just be careful to search for the proper graphs otherwise things might go crazy (this is valid only for Eternity).

Later edit 2: I went to people smarter than me here and learned that the parameter I was mentioning is the gm (transconductance, this case ratio but anyway).


----------



## mordy

OctavianH said:


> You were lucky but do not try this too often. Your 6BL7 was heavily used and this is why you were able to use it at around 70% of the datasheet specs. But this is not always the case. For short periods of time I guess it is fine (you stop the amp if you see that the current raises too much and that's it) but look at this 6SL7 graph. We would need around -0.7V for 3mA. Right?
> 
> 
> 
> ...


Somebody said that tube testers are only good in telling if a tube is bad but not for measuring tubes…


----------



## DecentLevi

Thanks again for your help Octa and Tomas. I actually had no memory of the output tubes handling being changed to 400v but I've taken note. Took me until just yesterday to learn how to read the simple graphs, anything more than that may be a challenge. In my school days I could still never grasp _pre_-algebra after two full semesters, one of my mental handicaps as a special-ed student. Ironically I am brilliant with schematics in relation to audio signal processing as a sound design artist / producer.

Actually it turns out -10.6v was the perfect staring point for 6BL7 on my amp. I have 4x mint condition nearly NOS 6BL7 tubes with two lettering variations, and all needed at least 3-5 half turns of the milti-turn trimmer to finally get up to at least 3mA on the meters. I'm still staying closer to 3mA to not push it too much. They have (one at a time) been performing solidly with no part of the amp overheating, even with multi-hour sessions and a movie. The sound I'm getting is vivid, full, sweet, weighty and a downright sublime first class experience. The pairing with EL38 output tubes is really special! EL39 are aplomb also and darker.

Now to rustle another feather... I checked the brand and of these are all GE. I guess even GE can sound good sometimes.


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## DecentLevi (Oct 7, 2022)

Per the other recommended lower gain input tubes. Cathode adjustment needed is specific to my amp.

*6BX7*: would need around -18v but mine only goes to -10.6v so I better skip this one.
*BL63 *This tube looks nice but I couldn't find any curves for it on the datasheet. I also checked equivalents CV1102 and VR102. They're costly though.
*76 & 37* tubes: around -10v for me. Wow those look great and are available. I will probably get two 76 to 6J5 adapters.
*5687*: around -10.6v perfect, but I would need a special adapter. Any recommendations for miniature tubes compatible with the E80CC (12A*7) or E88CC (6DJ8) pinout with lower than 20 gain? I have adapters for those types.
*12BH7*(A): -9v. Here's a miniature tube I came across with a gain factor of 16. According to the equivalents it looks like it's compatible with E80CC which is intriguing since it's a 6v tube(?)


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## Isaacc7

DecentLevi said:


> Per the other recommended lower gain input tubes. Cathode adjustment needed is specific to my amp.
> 
> *6BX7*: would need around -18v but mine only goes to -10.6v so I better skip this one.
> *BL63 *This tube looks nice but I couldn't find any curves for it on the datasheet. I also checked equivalents CV1102 and VR102. They're costly though.
> ...


You could also look for a 6ah7 or 7ah7. Same tube, different base. You'd need an adapter for either one. Not as common as the 12v versions but not too expensive when you find them. Mu of 16.


----------



## JazzVinyl

DecentLevi said:


> Per the other recommended lower gain input tubes. Cathode adjustment needed is specific to my amp.
> 
> 
> *5687*: around -10.6v perfect, but I would need a special adapter. Any recommendations for miniature tubes compatible with the E80CC (12A*7) or E88CC (6DJ8) pinout with lower than 20 gain? I have adapters for those types.



ECC804 has gain of 18.  In the Glenn OTL it sounded a lot like a pair of C3g to me (minus the metalic tinged treble). Uses the same adapter as a 6922/ECC80 (I believe). 

@gibosi turned me on to this tube.   It is a goodie...there are examples by Mazda and by GEC (both appear to have been made in the same factory)?
Not expensive, most commonly found in the UK (and the pound is way way down right now).

A quick look at the curves, it appears it will be right in your "sweet spot" range of cathode bias perfection...

http://www.r-type.org/exhib/abo0077.htm


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## DecentLevi

Isaacc7 said:


> The 31 tube uses the same pin out so you could use them as well as the 76 with the same adapters. Both the 76 and 31 also have the benefit of being pretty cheap as well.


Are you sure the 31 & 76 tubes can use the same adapter? I'm having a custom adapter made to 6J5, but he said the sockets are different. Is it just that the 31 has less pins?


----------



## gibosi

DecentLevi said:


> Are you sure the 31 & 76 tubes can use the same adapter? I'm having a custom adapter made to 6J5, but he said the sockets are different. Is it just that the 31 has less pins?



Your adapter maker is correct. The 31 will not work in the same socket as the 76. But I think it is a typo. Instead of 31, it should be 37.


----------



## Isaacc7

gibosi said:


> Your adapter maker is correct. The 31 will not work in the same socket as the 76. But I think it is a typo. Instead of 31, it should be 37.





gibosi said:


> Your adapter maker is correct. The 31 will not work in the same socket as the 76. But I think it is a typo. Instead of 31, it should be 37.


Whoops! You're so right. Sorry about that!


----------



## mordy

JazzVinyl said:


> ECC804 has gain of 18.  In the Glenn OTL it sounded a lot like a pair of C3g to me (minus the metalic tinged treble). Uses the same adapter as a 6922/ECC80 (I believe).
> 
> @gibosi turned me on to this tube.   It is a goodie...there are examples by Mazda and by GEC (both appear to have been made in the same factory)?
> Not expensive, most commonly found in the UK (and the pound is way way down right now).
> ...


The ECC804 has the same pinout as the 6DJ8 family. The 6CG7 also has this pinout, so an adapter that says 6CG7 to 6SN7 will work.
There are inexpensive Chinese adapters available but Deyan will make one of better quality. On the other hand you probably already have this kind of adapter.


----------



## OctavianH

As far as I know 6922/E88CC/6DJ8/6CG7/ECC804 work with the same adapter but never tried all these.


----------



## OctavianH

I've been incredibly busy recently but this weekend I managed to find equilibrium. So, we prepare for an evening with Eternity.






And the way my beer pint looks at my headphones is like:


----------



## mordy

OctavianH said:


> I've been incredibly busy recently but this weekend I managed to find equilibrium. So, we prepare for an evening with Eternity.
> 
> 
> 
> And the way my beer pint looks at my headphones is like:


Can you tell what kind of (exotic) tubes you are using? And what the beer is looking at?


----------



## OctavianH

mordy said:


> Can you tell what kind of (exotic) tubes you are using? And what the beer is looking at?


Absolutely, there is nothing exotic there. I use a pair of GEC ATS25 for output and a Telefunken ECC801S for input (the one in the middle). The 2 GEC L63 (6J5) are just for looks since my input selector is set to double triode. These GEC ATS25 are seen by many as a premium version of 807, a tube I am fully proud of. The Telefunken ECC801S is a type of 12AT7 I like a lot for clarity and high frequency extension. It pairs very well with the GEC full bodied sound provided by the ATS25. The headphones are Final Audio D8000 Pro. These are my end game, I have sold all my headphones since I have bought these. I am fully convinced I might find something better, but at a much higher price (Susvara or maybe 1266 TC) but I do not need more. These are the ones I was looking for since I was born


----------



## UntilThen

What is the unit under Eternity? Your layout at the end of the table was where I had mine before. It's now on racks for me. To free up space for another monitor and my printer.


----------



## OctavianH

UntilThen said:


> What is the unit under Eternity? Your layout at the end of the table was where I had mine before. It's now on racks for me. To free up space for another monitor and my printer.


Under Eternity I have a Cambridge Audio CXC CD Transport. I am not using it a lot lately so I might renounce on it. It was intended for CD playback but... I listen mostly to my digital collection.


----------



## UntilThen

OctavianH said:


> The headphones are Final Audio D8000 Pro. These are my end game, I have sold all my headphones since I have bought these. I am fully convinced I might find something better, but at a much higher price (Susvara or maybe 1266 TC) but I do not need more. These are the ones I was looking for since I was born



You don't need more. I heard the Final D8000 Pro is good. I stop lusting for the Abyss 1266 TC because I remember I didn't like the Abyss 1266 Phi which I heard several years ago with Ragnarok and Woo Wa5le.


----------



## OctavianH

UntilThen said:


> You don't need more. I heard the Final D8000 Pro is good. I stop lusting for the Abyss 1266 TC because I remember I didn't like the Abyss 1266 Phi which I heard several years ago with Ragnarok and Woo Wa5le.


Well I guess I'll never listen to it. For me the D8000 Pro is enough and I do the rest with tubes. They are very transparent and lively, so I can tweak them a lot with tubes. Perfect for me and what I do.


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## OctavianH (Oct 1, 2022)

It is very hard to change something in the phase 3 of my experiments. All the combos are good enough to let you forget about the equipment and listen to music. And when you listen to music you do not really care about equipment, if it sounds right. This is why my activities are delayed. One of the plans was to revisit all my EL34 collection and assess it based on my new discovieries, the novals. Today I found some energy to switch my outputs from GEC ATS25 I was praising last evening to Mullard EL34 xf2. If you start with EL34, these are always the first choice. In my opinion these are the best, but they are followed close by old Tesla EL34 production. So here we are, Mullard EL34 xf2 with Telefunken ECC801S.






Soundwise these are clearly more relaxed that 807 and are somehow towards the KT77. But the good thing is that the Mullard EL34 xf2 is creamy, laid back, and masks some imperfections from the recording era. On this very clean sounding amplifier this is a quality, because you can go more towards that "analogue" sound many praise and mask a little bit from the imperfections of a pure solid state reproduction. Nothing is dry here, nothing scratches the surface, Mullard EL34 xf2 remains one of the best outputs for UltraSonic amplifiers because it provides what we need here, a laid back and solid sound.

So here starts my journey of reassessing EL34. I have a lot of tubes of this kind and I am fully convinced I'll have very interesting results with these tiny 12A*7 but the real challenge is to change something. Everything is so good you just want to open a new beer or work on something.

Later edit: I called EL34 a kind of KT77. Well, many consider KT77 a premium version of EL34 but for me these tubes are in their own category. I will explain. KT77 is for me the best I have ever heard on Eternity, and even if maybe electrically can be related to EL34, I keep them as a separate tube. I should do the same for ATS25 because it is not quite 807, it is much more even if it derives from it. It is the same like Mullard ECC35, all call it a premium 6SL7, but for me it is in a different league, it even biases differently, much stronger than the casual 6SL7. I am sold to british tubes, these are the sound of music for me and ECC35, ATS25 or KT77 are for me reference. Maybe because I was born and followed the british heavy metal from 80s and I am a huge fan of older stuff like Black Sabbath? For me everything started from Black Sabbath, Led Zeppelin or Iron Maiden, maybe this is biasing my assessment and this is the reason I praise these british tubes. I will let you decide.


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## OctavianH (Oct 1, 2022)

The dark brown base of the Mullard EL34 xf2 is incredibly beautiful. No picture can make it justice, but I have tried.





I am very pleased about EL34 and I consider it a very good option for Eternity. Being able to use so many types of tubes natively (EL34, 6V6, 6L6, KT** and so on) is a strong point of this amplifier and if we look on the market, more and more vendors are releasing amplifiers wired for these. If we just look on the Cayin HA-3A or the rumors that the future Feliks Euforia amps will be wired to use KT88 in the output stage it is a clear point that these tubes are the future. I was lucky enough to understand this before the point when people start to buy these types and raise the prices and I have a good stock of EL34 and 807. I was also lucky that I got in contact with Tomas when UltraSonic was almost unknown and he was able to build me this wonder of an amplifier. His vision of the modern design of tube amps is also the future, and more and more people start to realize this and go into this path. I really think these amplifiers are the future and that UltraSonic will become a very big brand soon. I do hope I will also find time and enough reason to build the "ultimate Citadel" I was writing about on several topics. Why Citadel? Well, I always wanted to experiment different things and Citadel is for me the most appealing model. But not the common build, a Citadel wired to use the tubes I have mentioned (6V6 family with 6SL7 as input) and which will be able to find an operating point and accomodate the whole family. A tube rolling fully balanced amp with 12.6/6.3V heaters. But about it we have plenty of time to talk.


----------



## UntilThen

OctavianH said:


> The dark brown base of the Mullard EL34 xf2 is incredibly beautiful. No picture can make it justice, but I have tried.



Is that double O or double D getters? They are both good but D is just a bit more special sounding. My fav.


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## OctavianH (Oct 1, 2022)

UntilThen said:


> Is that double O or double D getters? They are both good but D is just a bit more special sounding. My fav.


Mine are double O getters. I have some Philips xf5 double D getter but are more towards neutral sound (like Telefunkens). These are thicker and warmer sounding, I like these a lot but I will revisit the other types as well soon.

Later edit: I found a picture of the Philips double-D getter near this pair of Mullard (branded Valvo) xf2 double-O getter.


----------



## UntilThen

OctavianH said:


> I have some Philips xf5 double D getter but are more towards neutral sound (like Telefunkens).



Unless we're talking about different tubes, my Philips Miniwatt EL34 xf4 double D getters have the best tube tone. Definitely not neutral. 

Anyway, I'm rolling in these metal base now for a listen - again. I don't find Philips tubes neutral leaning like Telefunkens. Not even these Philips Miniwatt metal base. It's just tighter than the D or O getters but still a very good tube tone.


----------



## OctavianH

UntilThen said:


> Unless we're talking about different tubes, my Philips Miniwatt EL34 xf4 double D getters have the best tube tone. Definitely not neutral


Yes, you have the Philips metal base ones, the most rare and expensive. Mine are these:





There is a website which describes types, very useful for me. Here.


----------



## UntilThen

OctavianH said:


> Yes, you have the Philips metal base ones, the most rare and expensive. Mine are these:
> 
> 
> 
> There is a website which describes types, very useful for me. Here.



I know because I posted this link before. These double D getters are the ones I have and they are definitely not neutral leaning. I put them on the same standing as the metal base in terms of euphony.


----------



## OctavianH

This means I will have to take a look on them again. They are stored in my tube boxes but I will bring out all my EL34 tubes to try. I find a very good synergy with 12AT7 and I am really enjoying them. This is much more above 6SN7 or 6SL7. It seems EL34 loves 12AT7 on UltraSonic amplifiers.


----------



## DecentLevi

Incoming yesterday was the 12BH7A by Philco, a miniature tube that uses an E80CC / 12A*7 adapter. It worked as expected with the manual bias settings I plotted for it. I was getting a vivid, dynamic and and quite transparent sound, possibly bright. Later the brightness gradually became more apparent, so I switched to another tube I'm more familiar with, and it hit me how much low end and overall body I was missing. Chalked it up to being a first listen of my system for the day, maybe I should've started a fresh listening session with a familiar point of reference. I hope to not discriminate (LOL), but I'm not sure the 12BH7's in general have what it takes. There's a lot of other brands and designs of these, but overall miniature tubes have their place - namely in dynamics, sweet tone, vividness and clarity, but usually seem to fall short on the likes of soundstage and presence or instrument separation - save for select rare holy grail gems. 

This tube was part of the journey I'm on testing a theory that lower gain tubes are able to reduce the amps' background hum. Much testing with both this and 6BL7 has confirmed to me that while that is possible with a quiet enough tube and on low gain settings, the tendency is to increase the gain knobs to make up for the lower gain of the tube - thereby achieving equal performance with perhaps 3rd (of 4) gain setting of what I would have achieved on 2nd gain setting with a normal gain tube - so any benefits of having a quieter tube now cancelled out by increasing the gain which also equally increases the hum.


----------



## OctavianH

DecentLevi said:


> This tube was part of the journey I'm on testing a theory that lower gain tubes are able to reduce the amps' background hum.


It is sad to hear you are still facing hum issues. My amp is dead silent regardless of the headphones I use or the tube types I try. I've had headphones in range of 20-600 Ohm and I never heard anything more than music.


----------



## UntilThen

OctavianH said:


> It is sad to hear you are still facing hum issues. My amp is dead silent regardless of the headphones I use or the tube types I try. I've had headphones in range of 20-600 Ohm and I never heard anything more than music.



Likewise both my Oblivion and Odyssey are quiet with no music playing. I don’t understand Levi’s amp. I think he has ground loop problems in his home.


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## OctavianH (Oct 6, 2022)

A little bit of blue in the morning. But for a short period of time because I never got to like these Sophia Electric EL34. Besides the build quality which for me is under the NOS variants (light plastic bases, overall feeling fragile in hand), the sound is also under my expectation for EL34. I will try to explain, these are thin sounding for me, detailed but somehow sterile. I can compare them somehow to the Psvanes CV181T2 which are sold with Euforia. If you like those you can imagine these in the same direction. On my amp definitely not a good pairing, and I am unsure if someone searches for this type of sound from EL34, usually we want a more holographic and warm presentation.





So I went to some brown towards afternoon and chose the Philips EL34 xf5 (date code L1L, double-D getter). These are indeed exceptional and my task is to decypher them when used with some 12AT7. Clearly more detailed and less sweet than Mullards xf2, but still nice and full sounding. I was lucky to get these because they are quite rare.





On input there is another special one for me, a Philips 12AT7 (date code Tk1 Δ7F - Heerlen).


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## DecentLevi (Oct 25, 2022)

So, people think the hum on my amp is my fault. It's not, and here's why. Innumerable trials and troubleshooting have shown the issue is internal. After reading the below list you will see I have likely tried everything that is known and even into the unknown.
TLDR: My amp is a unique build I requested (probably erroneously), and I do not recommend this specific design I call Finyssey. Go for auto-bias instead.

Hum reduction remedies I have tried:

Touching the ground connection, RCA jacks, outside of transformer and chassis with my bare hands. Normally for a ground loop issue, the hum would have been momentarily quelled or reduced by this way
Power conditioner: My system goes through a Furman IT Ref-15i. This is a heavyweight TOTL performer is in great shape and is worth over $3k
Aftermarket AC cables. Tried 2 different types with thick gauge, and even combined it with an additional inline power filter
Faraday cage: created a makeshift faraday cage with tin foil that fully wrapped around the Sowter transformers with a non-conductive inner shielding to not touch any metal
Tube rolling: Tried many dozens of combinations, including brand new factory sealed & tested KT88s paired with multiple trials of perfectly matched and tested input tube combos. Some were the same combos that were silent on previous amps. There is some variance of hum/buzz level depending on the tubes but only around 1/4th of the noise coming from the tubes, with the remaining approx. 3/4th of the noise 100% constant from the amp regardless of configuration
Fuses: cleaned all internal/external and AC power supply fuses (5x) with isopropyl alcohol applied a thin layer of contact enhancer
Ferrite clamps: tried them on: Tubes with top cap wires, around a dozen on key wires internally on the power section, and elsewhere on my chain (fidelity improved in many areas, but not hum)
External inline headphone volume limiter: had to reduce the volume by 50% to not hear it, and by then everything good about the sound had been squished / compressed
2x external ground loop noise isolator units connected to my 'dummy' sockets that are connected to the ground signal of the amp
Vibration absorption feet under the amp + stacked with sorbothane sheet. Reduced the hum by a bit, and improved the sound performance! Alas, not enough reduction by a longshot
Headphones: tried 6 different pairs with sensitivity hovering around 95db and 32-600 ohms
Tried the amp with *0* tubes towards when I first got it. The same background hum was still present that was always there. I have not tried the amp this way again since.
Tried a Klein Tools RT110 Outlet AC Tester, which shows this house is wired properly
Throughout all of the above, the lion's share of the hum was constant and unchanged; the same background sound I heard the once I tried without any tubes. Designer Tomas mentioned my new amp does have some noisefloor and mentioned he heard a very modest hum when building it, but his headphones are less sensitive. I've definitely got plans for less sensitive headphones when funds permit, such as the HEDDphone at 87db. With a recommended max. 90db sensitivity to reduce the hum on this build however, my choices are quite limited. The entire Senn. line of headphones is out, along with most ZMF, Hifiman Susvara, most Audeze, etc., as most all are around 100db. The hum is just loud enough to hear during semi-quiet passages of music and bothersome during silence - only on the _most ideal setup _with my very few tube combos that are the quietest. Anything more than 2 (of 4 max.) gain position it becomes ridiculously obvious; along with many of my favorite tube combos, many of which I'm unable to use for this reason. This amp design is prone to highlighting any minute hum of a tube, and I've learned that the gain factor of input tubes can increase / decrease the main source of hum of which originates from the Sowter transformer _on mine_. Alas, input tubes with lower gain made it quieter but I needed a higher gain knob position to get the best sound, cancelling out this effect.

Environmental considerations

My exact same power supply & AC cables were dead silent with about 6 former SS and tube amps of differing types, including with the initial version of this very same amp
After the revision which included addition of hefty 15 watt Sowter transformers, I started hearing the hum (this was after my requesting auto-bias output tubes)
My "Finyssey" amp is a custom build. It is the only one that has a combination of auto bias output, manual bias input, and user selectable 4 gain settings. These along with other possible design elements may have something to do with the noisefloor on mine
Input tube circuit issue

Making things even worse for me, is that for the last couple months I've been dealing with a seriously disruptive issue with the input tubes! For most dual input tube combos (using the 2x 6J5 sockets), starting the amp will cause an intolerably LOUD hiss on the left channel, with the left mA meter dedicated to the left input channel not moving. In every iteration of this issue, I am able to switch the input tubes from R to L side, and the issue is only on the left channel regardless of tube condition or tube class (6J5 and 3-4 other types with adapters all do the same thing, around 8 pairs of good tubes). To make it weirder, about 1 of 10 times the amp will STILL WORK with the precise same combination smoothly without flaw, and that the single input tube socket (6SN7 class) still works 100% of the time, even though it is said to be wired in parallel to the dual tubes.

It is thought a pair of Valvo EL11 that may not have been tested could've caused a short-out of some sort. Since then I've discarded said tubes right away and only been using tubes that are well tested. Troubleshooting has included my replacing / soldering in a resistor in the input tube circuit that was found to be partially fried / dark, but that tested stable on a my Voltometer at about 90% efficiency. Also I cleaned all tube socket pins as instructed on the main thread with a fine metal scraper and slightly nudging them back into an optimal grip. But problem still persists. The fact that my amp does still work exceptionally with the single input socket, and with dual (2x) tubes at odd random times (such as after a 12+ hour cool down period) means that operation is not necessarily causing further damage to the amp, but what's been done has been done.

I have found a few local audio service technicians experienced with tube amps and I am saving up a few hundred $$ so I can take this thing in for local repairs so I don't have to return for a 2nd time to Poland.

What? My amp still sounds good? 
Yes!! Ironically I am listening to this gem of an amp as I type! I am getting an absolutely immense sonic experience from the Finyssey! Outstanding sense of real-life touch, huge soundstage, vivid, true sound unlike anything I've ever experienced at home and better than many top setups at CanJams, with dynamics in droves and ability to dial in a change of signature - that is, with tubes that don't A: amplify the hum too much or B: cause a frightening white noise hiss on the left channel. As you can see my experience is very limited at present. But nevertheless, Tomas has done such an impeccable job and this amp still has so much potential that I am in it to win with a new fix!

With my unique amp build involving manual cathode bias adjustment, there are highly exacting usage instructions (bias settings with a Voltometer according to the tube type), and other functional instructions like a 5-min. warm-up / cool-down period and checking the mA meters for certain levels, which were explained to me. One bad pair of tubes _may have_ been the culprit, but alas my take-home is to go with auto bias. The main sonic difference I heard while manually fine tuning the bias was merely a change of volume, so no, I would say manual bias is not worth it. OTOH auto bias is said to allow for a somewhat higher tolerance level for less than perfect tubes, so that would be my recommendation for other users. Until I may potentially find the cause and solution, I do not recommend my design "Finyssey". I would imagine Odyssey would be the ideal option, the one UT has.


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## OctavianH (Oct 7, 2022)

I cannot advise you anything since I do not face any of those problems on my amp. And regarding fixed/auto bias I think it is a matter of preference. As far as I know auto cathode bias sounds a little bit more laid back and slower while the manual grid bias is faster and more in your face. You can see the same remark here in the last post. Everyone can choose whatever, but for me, if I can have a faster tube amp I'll go that way because of my musical preferences. Of course, I might be wrong, I do not have here 2 UltraSonic amps with different bias types to compare on the same headphone line. I just read stuff on internet about this and I remember my 2 amps Eternity and Elise but it is a little bit hard to compare both being quite different designs. I just know since I've switched to UltraSonic and manual grid bias I never faced those odd Elise moments when changing tube types and hearing a dull sounding amplifier because it needed some hours to "adjust". Not every time, but sometimes happened, and it was not about tubes heating or other stuff... Anyway does not matter anymore and I am not trying to be an advocate of manual grid bias. I just say what I remember about this topic. I fully agree auto bias is much more comfortable and cheaper in terms of matched pairs, but for me a crisper sound makes sense.

Later edit: I am fully convinced the auto biased UltraSonic amps do not have the problem I had on my Elise. It was maybe something specific to my unit. So do not understand wrong that cathode bias amps have that problem, mine had.


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## DecentLevi (Oct 10, 2022)

Per recommendations I got a pair of 37, 76 and adapters to 6J5 from Deyan. Both matched and tested well. For an unknown reason, although the 37 tubes work, they just sound terribly limp and dull. So bad I can't hear any details I'm used to, and drums don't even sound like drums, and even vocals are barely listenable. By far the worst tube I've ever heard. Tried it with a range of output tubes also. I could only speculate synergy issues with my amp design, but I did manually adjust the cathode bias properly. Or maybe it's because of the brand.





These are matched, even though the labels are different.

I'm still testing the 76 tubes, which happen to be a random pair that aren't working in my amp due to a previously mentioned issue that I'm looking into getting repaired.

By contrast, the Sylvania Jan-CHS-6SN7W silver top take this amp well into the land of enchanted performance with vivid, silky mids and dynamics to stop you in your tracks. Though I'm always aiming for dual input tube setups. My hunch early on that 2x input tubes will sound better having two single triodes separated in two separate tubes was absolutely spot on. Extensive comparisons have shown an unwavering preference to ultimate fidelity, purity, soundstage, inst. separation, etc. of a good dual tube combo can never compare to a single input tube.


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## Isaacc7

My amp will be ready soon. Trying to wrap my head around the tubes I have and what I can use in my new amp. Here’s what I’ve got:

Input tubes

6/12n7 Sylvania x5, RCAx3, GEC, Tungsol BGRP, Fivre
6f8g Raytheon x2, Sylvania
6/12j5gt Sylvania, Raytheon, RCA, National Union, Ken Rad, Radiotron Aus.
6c5G Cossor/Mullard?

All of those can be used as either inputs for my amp or in my preamp. 

Other input tubes for amp only

Cv1102/bl63 MOV
6c8g Tungsol
6n7 Mullard, visseaux 
6/12sl7 Sylvania x4, RCA, Tungsram, Brimar, Fivre

Power tubes

6f6 RCA, Ken Rad
6k6gt RCA, Tungsol
6/12v6 Sylvania x 3, Ken Rad
6aq5 Brimar, Mullard, Miniatron, Telefunken
6ar6 Tungsol
El38 Mullard, GEC E3375
El34 Raytheon Japanese
807 Cossor/Mazda, Mazda (France), Fivre, Sylvania 5933, Firenti Russian, STC
7581a Tungsol new, Sylvania
KT66 Gold Lion new
GU50

I might also try out 2e26 and 12av5 in the future. So with that I think I will put a bow on it, stick a fork in it, pencils down. I can only think of a few other tubes that I am interested in buying (more GEC b36 and 6bg6g) but they will have to wait. No more tubes. As it stands I don’t think I’ll be able to get through all the combos I have. Keep in mind a lot of those output tubes can also be run in ultra linear as well as triode. And my preamp (Supratek Cabernet) will change the sound when I change tubes in it as well. That just adds to the permutations. With these tubes and my new amp I’ll have plenty of different sounds to play with. It‘s coming soon!


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## OctavianH

While you are preparing for complicated tests, I am here going for simplicity. No adapters,  native tubes, good sound. The Brimar CV1985 with GEC KT77.





I wanted in the past to try a 37 but in my amp it requires around -15V for grid bias and my trimmer goes maximum to around -13V. So, no 37 for me on this amp.


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## UntilThen

Isaacc7 said:


> My amp will be ready soon.



Exciting.


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## OctavianH

Isaacc7 said:


> With these tubes and my new amp I’ll have plenty of different sounds to play with. It‘s coming soon!


When? One week already passed.


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## UntilThen

OctavianH said:


> When? One week already passed.



24 more screws to be put in.


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## OctavianH

UntilThen said:


> 24 more screws to be put in.


Great! As a manager would say, if we mount 1 screw/hour we'll have it tomorrow at noon.


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## UntilThen

OctavianH said:


> Great! As a manager would say, if we mount 1 screw/hour we'll have it tomorrow at noon.



 My reasoning is that if we start from the bottom, we will get to the top. So I bought a pair of these from a friend of mine today. It was a special price.  Like $1.


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## Isaacc7

OctavianH said:


> When? One week already passed.



Apparently there is an issue with the power transformer that Tomas is trying to figure out a solution to. Other than that it is built!


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## OctavianH

I was lucky enough to find a pair of Brimar CV1932 I was thinking about for a long time. I think a pair like this used Tomas to test Eternity  before seding it to me and are also the ones from the official pictures of Eternity available here.





I was more than lucky to have these matched around 10% and usable on my stock bias option. So no need to adjust anything, just plug and play.





And soundwise, well, top class. Very detailed and clean, they  have that noble sound I always liked on CV1985 for example.


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## SonicTrance

OctavianH said:


> I think a pair like this used Tomas to test Eternity before seding it to me and are also the ones from the official pictures of Eternity available here.


You’re right. I have a quad. Very nice tubes! 🙂


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## OctavianH

SonicTrance said:


> You’re right. I have a quad. Very nice tubes! 🙂


Take care of them, I always considered Brimar to be very nice balanced and aristocratic sounding. I like these very much but it is not easy to find them.


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## Isaacc7

OctavianH said:


> I was lucky enough to find a pair of Brimar CV1932 I was thinking about for a long time. I think a pair like this used Tomas to test Eternity  before seding it to me and are also the ones from the official pictures of Eternity available here.
> 
> 
> 
> ...


I have a pair of the 12sl7 version. Haven't tried them yet though.


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## OctavianH

Good times are coming. I was able to get a cheap bundle of used 6SN7 of various brands and this is the perfect pretext for me to return to the "infamous" 6SN7 and see if I will like them more than on Elise, where, honestly, I have not quite used them. At those times I tried several unicorns but never really got into them. The Psvane CV181T2 with Tung Sol 5998 was my favourite combo until I discovered KT66 with 6V6. And from that point I never or rarely changed something for short periods of time. When I sold Elise I sold mostly all my 6SN7 / 6AS7 collection to switch to EL34 or 807 and what I currently use. I had matched pairs and did not made sense to keep them. When I received Eternity I tried a few of the remaining ones and preferred 6SL7, 6N7, 6J5 and later 12A*7 or 6C4. So 6SN7 was never a big love of mine. However, I read periodically the dedicated thread and felt that I need to spend more time and learn more from these, the only problem was the price I was not willing to pay for them. But luckily I got this bunch of tubes, cheap and used, and now after I measure I'll try some of them on Eternity. I like used tubes, I do not need NOS values and I am able to check them so all has to be fine.





A nice surprise was that many of these measure much better than expected at 180V / 4mA and this shows that a tube measured in datasheet conditions is not always reflecting its measurement at your amp operating point. I am sure these have plenty of life left.

And another thing I'll try is a pair of GEC KT61 in both input/output positions.





I have to be careful to pair these with some higher gain outputs, because I expect these on input will need to turn up a lot the volume knob.

Ok, we  have a plan, now let's find energy to follow it. Hardest part is to remove GEC KT77 from them amp because every time I decide to do that I just realize it sounds perfect and I postpone my actions.


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## mordy

OctavianH said:


> Good times are coming. I was able to get a cheap bundle of used 6SN7 of various brands and this is the perfect pretext for me to return to the "infamous" 6SN7 and see if I will like them more than on Elise, where, honestly, I have not quite used them. At those times I tried several unicorns but never really got into them. The Psvane CV181T2 with Tung Sol 5998 was my favourite combo until I discovered KT66 with 6V6. And from that point I never or rarely changed something for short periods of time. When I sold Elise I sold mostly all my 6SN7 / 6AS7 collection to switch to EL34 or 807 and what I currently use. I had matched pairs and did not made sense to keep them. When I received Eternity I tried a few of the remaining ones and preferred 6SL7, 6N7, 6J5 and later 12A*7 or 6C4. So 6SN7 was never a big love of mine. However, I read periodically the dedicated thread and felt that I need to spend more time and learn more from these, the only problem was the price I was not willing to pay for them. But luckily I got this bunch of tubes, cheap and used, and now after I measure I'll try some of them on Eternity. I like used tubes, I do not need NOS values and I am able to check them so all has to be fine.
> 
> 
> 
> ...


Be careful! Sometimes after you remove   that “perfect“ tube and then put it back after some time, it may not sound the same to you. 
Don’t know why this happens to me, but I have noticed it several times. - Maybe the brain needs to adjust, or whatever, but this is a fact to me.


----------



## Isaacc7

OctavianH said:


> Good times are coming. I was able to get a cheap bundle of used 6SN7 of various brands and this is the perfect pretext for me to return to the "infamous" 6SN7 and see if I will like them more than on Elise, where, honestly, I have not quite used them. At those times I tried several unicorns but never really got into them. The Psvane CV181T2 with Tung Sol 5998 was my favourite combo until I discovered KT66 with 6V6. And from that point I never or rarely changed something for short periods of time. When I sold Elise I sold mostly all my 6SN7 / 6AS7 collection to switch to EL34 or 807 and what I currently use. I had matched pairs and did not made sense to keep them. When I received Eternity I tried a few of the remaining ones and preferred 6SL7, 6N7, 6J5 and later 12A*7 or 6C4. So 6SN7 was never a big love of mine. However, I read periodically the dedicated thread and felt that I need to spend more time and learn more from these, the only problem was the price I was not willing to pay for them. But luckily I got this bunch of tubes, cheap and used, and now after I measure I'll try some of them on Eternity. I like used tubes, I do not need NOS values and I am able to check them so all has to be fine.
> 
> 
> 
> ...


I have been fascinated with the kt61 for a while. I have the loctal version kt81 and the 12v version n34. GEC warns that they should always be used in an auto bias circuit so I won’t be able to use them in my new amp. I briefly tried them in my SE amp and they sounded lovely. Just like aI thought they would. Unfortunately my SE amp runs them over spec so I didn’t want to put too many hours on them and age them prematurely. I’m scheming on ways to use these tubes and others with similar specs, especially the older 4v tubes.


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## OctavianH (Nov 1, 2022)

mordy said:


> Be careful! Sometimes after you remove   that “perfect“ tube and then put it back after some time, it may not sound the same to you.
> Don’t know why this happens to me, but I have noticed it several times. - Maybe the brain needs to adjust, or whatever, but this is a fact to me.


It also happens to me often. I like to think we have several "best of" combinations and those are dependant on the mood. But besides that, perception changes to me often depending on the level of stress or how tired I am. But even in these conditions, for me KT77 always remained on top of the other output tubes I tried.

In the next period I want to play with these 6SN7 I spoke earlier about. But I also want to identify and make some research about some of them which are unknown to me. As a glimpse of what's to come:






But the plan is to make pictures in good light and research a little bit about all of them. For example on the first row the first 2 from left are branded as "Haltron" but they are most probabily rebrands. They can be a good starting point for me.





Later edit:

While the green painted one looks similar with one RCA:





The one with red logo is still a mistery to me. No problem, we have time to find out about that one.


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## mordy

OctavianH said:


> It also happens to me often. I like to think we have several "best of" combinations and those are dependant on the mood. But besides that, perception changes to me often depending on the level of stress or how tired I am. But even in these conditions, for me KT77 always remained on top of the other output tubes I tried.
> 
> In the next period I want to play with these 6SN7 I spoke earlier about. But I also want to identify and make some research about some of them are unknown to me. For example 2 Haltron ones which I expect are rebrands.
> 
> ...


The red on could be a BRIMAR which is selling for a good price:


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## gibosi

OctavianH said:


> It also happens to me often. I like to think we have several "best of" combinations and those are dependant on the mood. But besides that, perception changes to me often depending on the level of stress or how tired I am. But even in these conditions, for me KT77 always remained on top of the other output tubes I tried.
> 
> In the next period I want to play with these 6SN7 I spoke earlier about. But I also want to identify and make some research about some of them which are unknown to me. As a glimpse of what's to come:
> 
> ...



And I agree, the one with the red logo looks like a Brimar.


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## OctavianH

mordy said:


> The red on could be a BRIMAR which is selling for a good price:


Good catch, I was searching in the same direction reading here.


----------



## triod750

OctavianH said:


> I like to think we have several "best of" combinations and those are dependant on the mood.


Agree!


----------



## triod750

The Haltron/Brimar looks exactly as my Brimar so I don't know what it is


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## OctavianH

I managed to get the GEC KT77 off the amp. It was hard. So I thought about a "reference" tube for output to be able to understand what is happening with these new toys.
And the best solution was GEC KT88, it is a little bit sweet in tone but, in rest, close to what many call "reference". And my pair is heavily used, so no problem to stress it a little bit, I do not care about it too much.

First try, KenRad 6N7 with GEC KT88. I put them in the 6J5 slot, so both triodes wired in parallel. And as expected, a very warm and relaxed sound, I like it. 6N7 is a good option to make the KT88 more musical and add some bass here and there. Now I need a glass of whiskey.


----------



## OctavianH

I started on big horses with the 6SN7 but in the end remained on these Ken-Rad 6N7.





In combination with GEC KT66 which I find incredible on acoustical instruments, they add some warmness and weight and make everything more fluid. Exceptional combination for piano or vocals. This combo is a keeper and another proof that 6N7 is for me a very important type. Unfortunately I still cannot find myself comfortable with the 6SN7 and I will, of course, continue to check them and see where this goes.


----------



## UntilThen

I love my GEC KT66.


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## OctavianH (Nov 5, 2022)

And a small new chapter in Eternity's life: GEC KT61. Incredibly good sounding, above expectations. A 6V6 with GEC flavour or more? I'll have to decide this in the following days.





Bias was around -4V for 20mA @ 200V.


----------



## Isaacc7

OctavianH said:


> And a small new chapter in Eternity's life: GEC KT61. Incredibly good sounding, above expectations. A 6V6 with GEC flavour or more? I'll have to decide this in the following days.
> 
> 
> 
> Bias was around -4V for 20mA @ 200V.


Yup. That is exactly how I was expecting them to sound. The kt61 and el33 have the reputation of being amazing tubes as long as you don’t need a lot of power. I’m thinking of having an amp made specifically to use tubes in that power range.


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## OctavianH (Nov 5, 2022)

Isaacc7 said:


> Yup. That is exactly how I was expecting them to sound. The kt61 and el33 have the reputation of being amazing tubes as long as you don’t need a lot of power. I’m thinking of having an amp made specifically to use tubes in that power range.


They sound very good, at first I would say these are close to 6V6 but with that british aristocratic sound and somehow more powerful. I am impressed.

Later edit: I had to make another picture of these beauties.


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## OctavianH

Indeed, these GEC KT61 pair very well with 6J5. For example with GEC CV1067 L63.





This was an important milestone in Eternity's life, the KT61. I was not expecting that I would be so pleased about these, and soon I'll try them on input. I am curious about the gain in that case, I guess I'll pair them with some EL34 or higher gain outputs.


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## Isaacc7

OctavianH said:


> Indeed, these GEC KT61 pair very well with 6J5. For example with GEC CV1067 L63.
> 
> 
> 
> This was an important milestone in Eternity's life, the KT61. I was not expecting that I would be so pleased about these, and soon I'll try them on input. I am curious about the gain in that case, I guess I'll pair them with some EL34 or higher gain outputs.


Would you use an adapter to triode strap them for input Duty?


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## OctavianH

Isaacc7 said:


> Would you use an adapter to triode strap them for input Duty?


Yes, I asked Deyan to make me some 6V6 -> 6J5 adapters. The plan was to dwell more into KT61/KT63 area because 6V6 exceeds my bias trimmer. But these work well with grid bias under -13V and I can use them. I am unsure if these will sound fine on input, but on output they surely are better than 6V6 which sounded weak on this amp.


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## OctavianH (Nov 5, 2022)

Deciphering more from these marvelous GEC KT61, I realized that GEC always works with RCA for me, regardless of the type. I mentioned this when I played with ATS25 and also later with 12E1 or KT66. So I had to try my RCA 6SN7GT and voila! Great result. As expected, I might say.






RCA knows how to tame that excessive mid forward tone of GEC and adds a little bit of bass to the overall signature. In the end this tube rolling game is very simple when you start to realize how these house sounds work and then what adds each tube type. In the end you'll be the perfect cook adding this and that to match your perfect recipe and taste.

Today was a very rewarding day for me, discovering some new stuff which is excellent. Now, I guess, I should start listening to music instead of my equipment. In the last days I was quite absorbed by the latest Fleshgod Apocalypse album, Veleno, and today I went more on the extreme side listening to some Rotten Sound. Grindcore was always special to me, starting from my Napalm Death days. But for this evening I guess I'll return so some more "classical stuff" like Udo. I'll stop here because the purpose of the thread is tube rolling in the context of UltraSonic amplifiers and not about my personal music tastes. However, I mention them from time to time to remind people that my assumptions and assessments are quite biased by some personal preferences.


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## OctavianH (Nov 7, 2022)

Exactly after I complained about 6SN7, I had the idea to try the Raytheon VT-231. Wow, this one has a strong and controlled bass, I never  heard something like this from a 6SN7. Incredibly fast and powerful sounding tube, dynamics close to what I hear on 6SL7. More than this, this one biases around -7.2V while the average 6SN7 goes around -6.5V.





I do not know much about this one, but I'll try to find out  more. There are some things mentioned on the dedicated thread, but unfortunately the pictures are not available anymore to see the construction details of each type mentioned there.





It has a vertical square getter. I'll try to find out what "I3" means because it is most probably the date code.


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## Isaacc7

OctavianH said:


> Exactly after I complained about 6SN7, I had the idea to try the Raytheon VT-231. Wow, this one has a strong and controlled bass, I never  heard something like this from a 6SN7. Incredibly fast and powerful sounding tube, dynamics close to what I hear on 6SL7. More than this, this one biases around -7.2V while the average 6SN7 goes around -6.5V.
> 
> 
> 
> ...


I really like the Raytheon 6f8g with the same plate structure although I think they are black plates. I also love the Raytheon 12j5wgt with the flat ladder plates. Keep meaning to try some of the regular 6/12sn7 tubes.


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## triod750

Surprises usually come from where you don't expect them   .


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## OctavianH

triod750 said:


> Surprises usually come from where you don't expect them   .


It is true that I was surprised and usually when something like this happens I wait for another day to check again. But today the same impression. These are in another league in terms of bass and the overall signature is very nice. I'll continue to listen to this one.


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## OctavianH

Friday beerday! But first I had to make some order in my tube collection which decreased a lot lately. Eternity was for me a source of economy. I sold mostly all my 6SN7 or 6AS7 and newer production tubes and kept many used NOS I got here and there which are sounding a level better than the famous ones even if they do not measure as good as others. No problem for me.





But honestly all I need is this drawer. This is my stash I'll never leave and which gives me everything. And here we have mostly 6SL7, 6N7, a few 6SN7 and in rest, KT66/77/88, E3375 and 807/ATS25. That's all folks. Ah, I forgot about the GEC 12E1. Life is simple with Eternity, you do not need so many to be happy.





Ok, now we have time for a beer.


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## Thaddy

All of those tubes bumping against each other


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## OctavianH

Thaddy said:


> All of those tubes bumping against each other


Do not worry nobody is hitting them, they just sit there. And this is my used stash where I keep stuff I daily use. I never had a problem with these in years. The others sit in boxes, vertically, and so on... those I'll most probably never use. LOL


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## OctavianH

I circled around these 6SN7 trying to understand more about their nature but they were not able to impress me. Of course, except the Raytheon VT-231 I mentioned a few posts back. Today, while preparing to give up, I wanted to try the Haltron I identified with your help as Brimar made. And what a surprise!

This is a very special tube, exceptional, I would say.





It has incredible detail and a very large soundstage. I started to dig about it and I found very close to what I hear the remark of tubemaze from here. He describes better than me what I am hearing. Of course, it needs to be paired with outputs with good bass, but in rest it is not missing anything. 





I guess I can put all the rest of the 6SN7 to storage, I was never a fan of them anyway. But Raytheon VT-231 and Brimar 6SN7GT will definitely remain close.


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## Isaacc7

The first set of output tubes I put in were some Sylvania JAN 7c5 tubes. They are supposed to be identical to a 6v6. First set of input tubes were tall 7n7. In triode they were... fine. Kind of round and warmish sounding but also blah. Then I switched to Ultralinear and was shocked at the transformation. It was much cleaner and more detailed. After a while I found it a bit fatiguing. If you're familiar with the stereotypical sound of Sylvania 6sn7 tubes, extended top end, solid bass, open sound then you'll know how this sounded but x2. Sylvania on the input and output were just too much. Too forward and an emphasis on the upper mids/lower treble. MOV cv1102 sweetened up the sound considerably but after a while still noticed the fatiguing sound. Switched my preamp to Tungsol BGRP from Raytheon 12j5wgt and that helped but still wasn't enough. 

Finally tried a tube that I have never really had a lot of luck with, the RCA 6sn7. They always sounded thicker, more opaque, and a bit dry to me whenever I used them in my other amp. Turned out they are a good match with the 7c5. It really toned down the aggressiveness. In the end though, the 7c5 was still a bit much for me. This is completely different than what I got out of them in my SEP amp. In that they were very well balanced and a tad warm. 

And then I started to wonder, maybe that's what the amp's character is. That wouldn't be good. Dove into my tube stash looking for some more 6v6. I have a slew of pairs and triplets but finally found a quad of Sylvania grey glass 6v6gt to try. As I got ready to put them in I realized they weren't all the same tribes. I had two pairs of slightly different 6v6. Well, I wanted to know if the amp's character was going to override the tube's character so I put them in. I hope the audiophile police don't arrest me!

These sound completely different! Whew! The sonic presentation got much bigger and super rich/warm. Total chocolate cake kind of vibes. That was a welcome relief. but in a short while I heard what I had always disliked with the RCA 6sn7. The sound had flattened out, the dryness was there, and the bass was a bit wild. Switched back to the 7n7 tall bottle inputs and Raytheon 12j5wgt in the preamp. The Sylvania 6v6gt tubes are more laid back than the 7c5 and a bit warmer. This is closer to what I was getting with my SEP amp with the 7c5.

Listening more I felt like there was a subtle crunchiness to the sound. It reminded me of the distortion you get when you overdrive a mic preamp. So I backed off the voltage a little and that cleaned it up. So it looks like I will need to continue to experiment with operating points to get the best sound. I will try this tube in triode tomorrow probably and may try to find a better tube combo for the 7c5 in triode as well. 

My current plan is to stick with lower voltage tubes right now. After I've satisfied my initial curiosity with the 6v6 I will probably try the 6f6, 6k6gt, and 6aq5. I reserve the option to deviate from that though!


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## OctavianH

Isaacc7 said:


> These sound completely different! Whew! The sonic presentation got much bigger and super rich/warm. Total chocolate cake kind of vibes. That was a welcome relief. but in a short while I heard what I had always disliked with the RCA 6sn7.


I hear the same about RCA. On Elise I never liked them but on Eternity they became my favourite american type.

Can you tell me a little bit more about the Triode/Ultralinear modes and differences? You said triode is rounded while ultralinear is clean. It goes towards Solid State sound or? What is the situation with the bass on ultralinear compared with triode mode?


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## triod750

OctavianH said:


> I hear the same about RCA. On Elise I never liked them but on Eternity they became my favourite american type.
> 
> Can you tell me a little bit more about the Triode/Ultralinear modes and differences? You said triode is rounded while ultralinear is clean. It goes towards Solid State sound or? What is the situation with the bass on ultralinear compared with triode mode?


Good questions!


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## Isaacc7

OctavianH said:


> I hear the same about RCA. On Elise I never liked them but on Eternity they became my favourite american type.
> 
> Can you tell me a little bit more about the Triode/Ultralinear modes and differences? You said triode is rounded while ultralinear is clean. It goes towards Solid State sound or? What is the situation with the bass on ultralinear compared with triode mode?


I’m still in the process of figuring it out. I have mostly been using ultralinear so far, haven’t even tried triode yet with the Sylvania 6v6gt. When I think of a “solid state” sound the first thing that comes to mind is a homogenization of timbres. One of the classic symptoms of schizophrenia is “dull affect.” It’s a dulling of emotional emote leading to a kind of sameness for all of their reactions. That’s the best way I can describe how most solid state amps sound to me. So in that context, no, ultralinear does not sound solid state to me. The short comparison I did with the one tube between ultralinear and triode made me think that ultralinear is cleaner and had more jump. On the other hand I also found that particular tube rather fatiguing to listen to. Not having that problem with these tubes. Once I get in the proper cables I will eagerly try the 14c5 tubes I have. They have the same grey glass appearance as these 6v6gt but the micas are different so they’re bound to be different tubes. 

In regards to the RCA 6sn7. These are clear glass with the silver logo. I have an older, grey glass pair of 12sn7 that I will try once I can run 12v tubes. So many people like them I can’t help but think I just haven’t found the right combo yet.


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## OctavianH

Isaacc7 said:


> In regards to the RCA 6sn7. These are clear glass with the silver logo. I have an older, grey glass pair of 12sn7 that I will try once I can run 12v tubes. So many people like them I can’t help but think I just haven’t found the right combo yet.


Like this one?


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## Isaacc7

OctavianH said:


> Like this one?


Yup, that’s the one. I also have about a million of the 12sn7 versions of it for some reason.


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## OctavianH (Nov 18, 2022)

Weekend comes, so we need to listen to the weekend tubes.





I prefer on Eternity these GEC KT66 grey glass instead of the clear ones. The nature of this amplifier makes me always choose the creamy and bass instead of a slightly more clarity. On my previous amplifier things were exactly the opposite.

And I've realised another thing: this Brimar 6SN7 I was praising a few days ago is excellent with almost everything you throw at it and somehow enhances it. It is very transparent, letting somehow the output tube to dictate the signature, but somehow widens and cleans everything. A very special tube, excellent for output rolling.


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## triod750

Those KT-66 apparently come from Swedish military.


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## OctavianH

You are right, I bought them from Sweden.


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## triod750

I see that on the storage code in red(ish).


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## OctavianH

Bad guys the swedish army, they are paiting with that ugly red these nice old british tubes. I never understood why, we all know it's a KT66 

Thinking on the difference between the clear glass and grey glass I wonder if my "upcoming" Citadel is a wise decision. Or if an amp with ultralinear will be of my interest. All claim those are closer to neutral/clinical than my Eternity and on it I usually choose tubes regarded as warm on it (EL34, 807 and so on). But here @Isaacc7 will help me decypher the mysteries of ultralinear and be prepared to make the right decision. Another crazy thought went through my mind: Eternity V2. But who is crazy enough to own 2 similar amplifiers and the first one I'll never sell so...


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## triod750

If Eternity 2.0 would be better than what you now have, or different enough, you might not need anything else (for a while).


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## OctavianH (Nov 19, 2022)

triod750 said:


> If Eternity 2.0 would be better than what you now have, or different enough, you might not need anything else (for a while).


Eternity 1.0 is exactly what I need. But of course there are minor things to consider. It will be 90% the same, but I will choose a bigger chasis to accomodate 4 x mA meters and get rid of those switches to monitor left/right channel. I have to unplug headphones while doing that and it's annoying. Its also true that I do this only with a new pair of tubes, I have charts and everything where I note bias and the strongest tube on the pair and always put it in the socket which is monitored. Other change would be to take 2 things from the other Eternity: a bigger trimmer on input to be able to use, for example, 37 or output pentodes and the removable anode top cap connection to be able to use EL39 / 4654K / 12E1 natively on the 6V6 wired output sockets. Another useful thing would be 12.6V heaters at least on input (maybe also on output) to be able to use 1625 (12.6V equivalent of 807) or others which are much cheaper and sound the same as their 6.3V variants. I guess that's all. But as I said, these are minor changes, Eternity is exactly what I was needing to be able to explore all these tubes I gathered here and the reward was infinite. Even if we think about money, such a flexible amplifier let's you customize your sound collecting tubes which have history and increase in value. Instead of buying 3-4 amps which you will never sell at the acquisition price after they are used. This is how I see Eternity V2 but of course, I do not see a real reason to ask for it, it can be a discussion for people interested in this type of design, to use my experience in tailor their build in a better way.

And of course, what I used less or maybe almost never on Eternity: Low/High gain selector, I usually keep all on Low and its fine. The only improvement I heard was on T1.2 600 Ohm where the High setting sounded better to my ears. Soundwise, there is a very slight difference in sound, but maybe 1%, High gain is somehow warmer and more relaxed while Low gain setting is more precise. As I said, almost imperceptible and most probably headphone dependant. Another feature I have not quite used is the ON/OFF for the VU meters. And in the end, XLR inputs, for convenience since this amp is SE. But of course, that is not something bad because I might use these in the future.

That's how I see the amp after around 18 months of heavy usage, this amps works for me 10 hours per day or more and has become a solid part of my life. First thing in the morning is to start it and let tubes warm before doing my coffee, so you guess how much I love it.

Now, since we discussed about the past, let's dive a little bit into the future. My curiosity for a fully balanced Citadel is more a matter of experiment than a need. I am curious to hear that design and compare it to what I know and heard. I want to see how much the tube flavour remains in that type of amplifier and up to which level of flexibility you can go in a balanced design. But of course, that complicates things: you need double triodes on input, you need quads on output and so on. And if you want single triodes on input (like 6J5 for example) then again, quads. So, better think twice, only for an experiment I doubt it makes sense.

Later edit: Forgot to mention here one important point. Having 4 x mA meters (for each tube) would be nice near a trimmer for grid bias / tube. This removes the necessity for matched pairs and allows, if needed, to use different types of tubes on each channel. This would be nice for comparison, to have let's say on left output a KT66 and on right one a KT88. I know, is sounds crazy but why not?


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## triod750

I like the way you think. And to explore something new isn't a bad thing to do if you have the means. Not as long as you don't rush into it. The idea of a removable anode top cap connection is very good. Being a pioneer overall is doing the rest a big favour .


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## OctavianH

Well, I was hoping to find other pioneers to build these and save my wallet.


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## triod750

But you couldn't rely on their opinion, could you? Their ears and their music? Their tubes? No way!!


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## OctavianH

Haha, your're right, there's no escape for my wallet.


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## Isaacc7

OctavianH said:


> Bad guys the swedish army, they are paiting with that ugly red these nice old british tubes. I never understood why, we all know it's a KT66
> 
> Thinking on the difference between the clear glass and grey glass I wonder if my "upcoming" Citadel is a wise decision. Or if an amp with ultralinear will be of my interest. All claim those are closer to neutral/clinical than my Eternity and on it I usually choose tubes regarded as warm on it (EL34, 807 and so on). But here @Isaacc7 will help me decypher the mysteries of ultralinear and be prepared to make the right decision. Another crazy thought went through my mind: Eternity V2. But who is crazy enough to own 2 similar amplifiers and the first one I'll never sell so...


Were you thinking about a push pull amp? Not sure if whatever I end up thinking about Ultralinear will translate to a single ended amp. So far, the 7c5/6v6gt is cleaner and more forward in Ultralinear as compared to triode mode. That seems to be the consensus in general from what I read.


----------



## Isaacc7

OctavianH said:


> Eternity 1.0 is exactly what I need. But of course there are minor things to consider. It will be 90% the same, but I will choose a bigger chasis to accomodate 4 x mA meters and get rid of those switches to monitor left/right channel. I have to unplug headphones while doing that and it's annoying. Its also true that I do this only with a new pair of tubes, I have charts and everything where I note bias and the strongest tube on the pair and always put it in the socket which is monitored. Other change would be to take 2 things from the other Eternity: a bigger trimmer on input to be able to use, for example, 37 or output pentodes and the removable anode top cap connection to be able to use EL39 / 4654K / 12E1 natively on the 6V6 wired output sockets. Another useful thing would be 12.6V heaters at least on input (maybe also on output) to be able to use 1625 (12.6V equivalent of 807) or others which are much cheaper and sound the same as their 6.3V variants. I guess that's all. But as I said, these are minor changes, Eternity is exactly what I was needing to be able to explore all these tubes I gathered here and the reward was infinite. Even if we think about money, such a flexible amplifier let's you customize your sound collecting tubes which have history and increase in value. Instead of buying 3-4 amps which you will never sell at the acquisition price after they are used. This is how I see Eternity V2 but of course, I do not see a real reason to ask for it, it can be a discussion for people interested in this type of design, to use my experience in tailor their build in a better way.
> 
> And of course, what I used less or maybe almost never on Eternity: Low/High gain selector, I usually keep all on Low and its fine. The only improvement I heard was on T1.2 600 Ohm where the High setting sounded better to my ears. Soundwise, there is a very slight difference in sound, but maybe 1%, High gain is somehow warmer and more relaxed while Low gain setting is more precise. As I said, almost imperceptible and most probably headphone dependant. Another feature I have not quite used is the ON/OFF for the VU meters. And in the end, XLR inputs, for convenience since this amp is SE. But of course, that is not something bad because I might use these in the future.
> 
> ...


There aren't all that many 12v output tubes out there. The ones that are out there usually aren't all that much cheaper than the 6v equivalent and/or the 6v is already kind of cheap. 12v6, 12aq5, 1625 are all a little cheaper but not as much as you might think especially if you have to buy new adapters like the 1625. Sure, the tt22 is cheaper than an original KT88 but still super rare. The gu50 is super cheap, especially compared to the original Telefunken. The n35 is only 15GBP and cheaper than a kt61 or el33 but if you already have kt61 tubes... 

So I don't think getting 12v outputs are really worth it unless you are really jonesing for the gu50. 12v inputs are an easy decision though. So much more reasonably priced. And I'm not up on this but I think that would also open up more possibilities with 9 pin tubes as well.


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## Isaacc7 (Nov 19, 2022)

I'm still working with the 6v6gt outputs. Settled on 280v 30ma in Ultralinear and 280v 35ma in triode. Ultralinear is more forward and cleaner sounding. The triode mode is fuller, slightly warmer, but more closed in.

I cycled through a variety of input tubes with triode mode:
1) Sylvania tall 7n7. Generally pretty good, well balanced.
2) Mullard ecc31 w/adapter. flat, mushy, clearly isn't a good match like they aren't compatible electrically.
3) Tungsol 6c8g. Dynamic, kind of "exciting" sounding. But a bit hot on the high end and fatiguing.
4) RCA 6sn7. Dry, wooly bass, ugh.
5) Raytheon 6f8g T plates. Probably the best combo. a bit more accurate sounding than the 7n7 and a better more solid bass.

In the end though, none of them really clicked. Everything still sounded too hot, too forward. That might change when I can try my 12sn7 tubes once I get the cables for the heater supply.

Then it occurred to me, instead of trying to tame the Ultralinear mode why not liven up the triode mode? My other amp sounded best with 6sn7 and equivalent. The 6sl7 always sounded hot and thin in it. I remember Tomas saying that the amp might actually be optimized for the 6sl7. Grabbed the easiest to get 6sl7, a pair of Sylvania brown base 6sl7w. Yup, these with the 6v6gt in triode are a good combo. It brought back the top end and tightened up the bass. Now I'm getting everything! Remember that the bottom getter Sylvania 6sl7 tall bottle was a bit more refined sounding so went and dug those up. Ugh, one of them was dead! Didn't light up at all! Found another and ahhhh... Yup, these are the perfect partner. They are smoother and "classier" sounding than the other Sylvania JAN brown base. This still isn't a warm sound but it is a very clear and transparent sound. Listened to "Ultraviolence" by Lana Del Ray and "Begin to Hope" by Regina Spektor. Their voices are pure and expressive and the rest of the mix supports them. Will probably try "The Trinity Sessions" by The Cowboy Junkies later tonight to finish off the female singers theme.

Tomorrow I'll try the 7c5 again now that I have the settings figured out. The 6v6gt seemed much warmer so I doubt the 7c5 will work with the same input tubes. I have some more exotic 12sl7 from Brimar and Tungsram to try in the future. Next week I'll be traveling for Thanksgiving but should be back on the tube journey the week after.


----------



## Isaacc7

Went ahead and put the JAN 7c5 Sylvania tubes in. First thing I noticed was that they drew way more current than the 6v6gt tubes despite supposedly being exact replacements. With some adjustment I run them at the same triode settings of 280v 35ma with the bottom getter tall Sylvania 6sl7. Big change, and for the better I think. Soundstage is deeper, better detail, more air. Going to leave this combo in until I get back from thanksgiving travel. Hope I'll be able to focus on family stuff and not dreams of my amp while I'm away lol.


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## OctavianH (Nov 20, 2022)

Isaacc7 said:


> Were you thinking about a push pull amp? Not sure if whatever I end up thinking about Ultralinear will translate to a single ended amp.


I was thinking in general if triode mode and ultralinear in the same amp would be a benefit for me. But later Tomas told me that this feature is available only on classic designs like Odyssey. So it goes somehow out of my scope because the reason I've chosen UltraSonic was the  new approach and modern designs. I am still documenting on this.


Isaacc7 said:


> So I don't think getting 12v outputs are really worth it unless you are really jonesing for the gu50. 12v inputs are an easy decision though. So much more reasonably priced. And I'm not up on this but I think that would also open up more possibilities with 9 pin tubes as well.


I try to stay out of the russian/chinese market because I have a lot of better options. But TT22 and 1625 and so on might be  useful, and who knows what we will find in the future. -13V maximum on input for grid bias was enough for me in 2020 but later I said why not to try 37 and realized I cannot bias it. Not a big problem but you know my theory: maximum flexibility if possible. So why renounce on something you might find useful tomorrow.


Isaacc7 said:


> I'm still working with the 6v6gt outputs. Settled on 280v 30ma in Ultralinear and 280v 35ma in triode. Ultralinear is more forward and cleaner sounding. The triode mode is fuller, slightly warmer, but more closed in.


My first impression of Eternity vs Elise was "much wider soundstage and more clarity and clean sound". But keep in mind that Eternity is a modern design, I have a feeling Odyssey is more tubey and the UL mode of it is close to what my Eternity sounds. So... we are discussing here most probably wine and whiskey. LOL


Isaacc7 said:


> I cycled through a variety of input tubes with triode mode:
> 1) Sylvania tall 7n7. Generally pretty good, well balanced.
> 2) Mullard ecc31 w/adapter. flat, mushy, clearly isn't a good match like they aren't compatible electrically.


Same here, I never really got into Mullard on Eternity. Does not sound very natural, it has a sweetness but somehow forced. At first I was pleased by novelty, later I realized it is not quite my type of sound and definitely prefer GEC and Brimar. Tried here on output Mullard 807 and on input ECC31, ECC32 and ECC35. Of course there is, like always, an exception: EL34 xf2 which is for me one of the best EL34 and in my opinion does not sound as "veiled" as the rest I've mentioned. Also ECC35 is somehow nice, closer to what I like than ECC31 and ECC32. I have a few pairs of Mullard 6C4 and some 12A*7 but I had no time for them yet. So I cannot say anything about those.


Isaacc7 said:


> 5) Raytheon 6f8g T plates. Probably the best combo. a bit more accurate sounding than the 7n7 and a better more solid bass.


I find 6SN7, 6F8G, 7N7 and 6CG7 sounding more or less the same. So not quite my type (with 3 exceptions: Forton 6H8C pre '55, Raytheon VT-231 and Brimar 6SN7GT which all go somehow off the classic sound of the others). And here it is also a simple electrical explanation, as far as I know all of these have the same electrical parameters except different base. So, makes sense somehow.


Isaacc7 said:


> Hope I'll be able to focus on family stuff and not dreams of my amp while I'm away lol.


Enjoy the weekend, you'll need at least one year to understand something from such an amp. I started a few months ago to really get an idea about what is  happening. At first I thought "I already know how x will sound" and was surprised to learn that the specific tube sounded different in Eternity compared to Elise. So I had to make a tour of my collection to get an idea about each one. Then I tried to make pairings based on what I've learned in the first phase. After I got 5-6 pairings I considered worth listening more, I started the next phase of letting each one 1-2 weeks and see where this goes... But in my case it was simple, you have several more variables to handle: UL/Triode mode, 12.6/6.3V (not sure if sound signature is different based on heater current) and so on.

I am trying this morning a quite epic combo: Brimar CV1932 with GEC KT66.






I like how these warmer GEC outputs (ATS25, KT66 grey, KT61) sound with Brimar and changing type (6J5 to 6SN7) is just slightly adding or removing something, the overal signature... remains based on what I call "house sound". Of course these do not quite work with KT88 or KT66 clear glass.

And we have the first deceased in the family, well my Philips ECG 6SN7WGTA I was keeping as placeholder on the dual triode slot, just to "light up" is dead. Well, we replaced it with a socket saver.





Not a big problem for me, I never liked this either, actually I guess it was the worse 6SN7 I've tried. I have somewhere another one, in one of the boxes, stored because I doubt I'll even listen to it. I might grab it to put it on the socket. I wonder if this feature of "all tubes light" where the one not selected by the input selector (single/double triode) has only the filament connected is somehow damaging something. I doubt, I guess it was just a tube which decided to die after some years. I doubt it  had any damaging effect on the amp since the input selector was on single triode, for the Brimars. So I guess the filament died or hell knows. Maybe I'll shock the community by chosing there a GE tube, I have somewhere a GE 6SN7GT I am sure the guys will love. LOL


----------



## Isaacc7

OctavianH said:


> I was thinking in general if triode mode and ultralinear in the same amp would be a benefit for me. But later Tomas told me that this feature is available only on classic designs like Odyssey. So it goes somehow out of my scope because the reason I've chosen UltraSonic was the  new approach and modern designs. I am still documenting on this.
> 
> I try to stay out of the russian/chinese market because I have a lot of better options. But TT22 and 1625 and so on might be  useful, and who knows what we will find in the future. -13V maximum on input for grid bias was enough for me in 2020 but later I said why not to try 37 and realized I cannot bias it. Not a big problem but you know my theory: maximum flexibility if possible. So why renounce on something you might find useful tomorrow.
> 
> ...


That particular 6sn7 is known to be terrible for audio. Philips branded Sylvania in general has a pretty bad reputation. I haven’t had any trouble hearing differences between different versions of *sn7 tubes and their equivalents. Different circuits will of course sound better/worse with different tubes but the 6sn7 family has a (well deserved IMO) reputation as a good sounding tube. My go-to Raytheon 6f8g has the same plate structure as the vt231 so it wouldn’t surprise me if they shared a sonic signature. 

Some of the Russian power tubes are really good. I am a big fan of the current “Gold Lion” KT66 and “Tung-Sol” 7581a. I’ve also heard nothing but good things about the Gold Lion KT77. I will admit to a prejudice against Russian small signal tubes. Haven’t heard one that I actually liked. It is what has prevented me from pursuing the Meltz bandwagon. Just as well, I have too many tubes as it is lol. 

I have a pretty positive view about Mullard in general. I really like the 807 from them. I also liked what I heard of their 6aq5. I bought the ecc31 based on the advice that with the right adapter it would essentially be the same as the crazy expensive ecc32. That tube has quite a reputation for sound quality. Sadly, neither of my amps has been sonically compatible. At least so far, maybe it’l be different with a different set of output tubes. The problems I have aren’t ones of taste it is basic electric compatibility. In my SEP amp the ecc31 sounded really phasey and had a crazy forward midrange. In Odyssey they sound for all the world like they simply can’t drive the 7c5. Dynamics, frequency range, tonality, all heavily compressed. There are some big differences between an ecc32 and a 6sn7 electrically. All I ever heard about was the increased heater demands. I’m still hoping I will be able to experience what so many other people have with those tubes. Also want my Visseux 11n7 to be in my quiver. So far they have suffered the same issues as the ecc31.


----------



## OctavianH

Isaacc7 said:


> I bought the ecc31 based on the advice that with the right adapter it would essentially be the same as the crazy expensive ecc32.


I can confirm that, at least on my amplifier, ECC31 sounded the same as ECC32.


----------



## Isaacc7

Switched to the Raytheon T plate 6f8g on the input. The 6sl7 is magical as long as the recording is immaculate. I have several favorite recordings that have a lot of high frequency energy and the 6sl7 really brought it out. The Raytheon 6f8g is a little more even keeled. 

Think I have the sound of these JAN 7c5 figured out, at least in triode. Many people associate the 300b with a warm, euphonic sound. And that is in fact how early amplifiers that used them sounded as well as amps based on the same circuits. More modern circuits and push pull take advantage of the 300b’s (and other low power directly heated triodes) inherent low distortion. I think those amps have more of a “pure” sound than romantic. Transparency, air, and purity of tone instead of euphonic creaminess. That’s the kind of sound I’m getting from these JAN 7c5 in triode push pull.  That thought crystallized while reading some posts on Audio Asylum where some of the old hands compared 6v6g in triode to the PX4. I haven’t heard a PX4 based amp but my current configuration does remind me of some systems I’ve heard built around push pull 300b and 2a3 amps. 

This is in contrast to my experience of the same tube in my SEP amp. I am used to hearing a slightly warm, kind of romantic sound. So yeah, looks I’ll have to relearn what my tubes “sound like” in my new amp. Should be fun!


----------



## mordy

OctavianH said:


> I was thinking in general if triode mode and ultralinear in the same amp would be a benefit for me. But later Tomas told me that this feature is available only on classic designs like Odyssey. So it goes somehow out of my scope because the reason I've chosen UltraSonic was the  new approach and modern designs. I am still documenting on this.
> 
> I try to stay out of the russian/chinese market because I have a lot of better options. But TT22 and 1625 and so on might be  useful, and who knows what we will find in the future. -13V maximum on input for grid bias was enough for me in 2020 but later I said why not to try 37 and realized I cannot bias it. Not a big problem but you know my theory: maximum flexibility if possible. So why renounce on something you might find useful tomorrow.
> 
> ...


Based on the picture it seems that the top of of the tube turned milky white. *If* that is the case, the tube lost vacuum. Once the air enters, the silvery getter flash becomes white and that is the death of the tube. Could be a microscopic or larger crack somewhere in the glass envelope.


----------



## OctavianH

mordy said:


> Based on the picture it seems that the top of of the tube turned milky white. *If* that is the case, the tube lost vacuum. Once the air enters, the silvery getter flash becomes white and that is the death of the tube. Could be a microscopic or larger crack somewhere in the glass envelope.


Yes, that was the case. I have no ideea why, the tube was sitting on my desk for a long time on some piece of paper. So no contact with anything or any kind of damage.


----------



## triod750

If there is an ever so slight leakage wouldn't this eventually happen when the getter is consumed?


----------



## mordy

OctavianH said:


> Yes, that was the case. I have no ideea why, the tube was sitting on my desk for a long time on some piece of paper. So no contact with anything or any kind of damage.


In my personal experience it has happened without any known reason, but at other times the tube cracked somewhere from being dropped or knocked against another tube in storage.
Usually, when the tube dies the white death, it is instant but sometimes it can be more gradual.
I have noticed that Russian tubes are more resistant to breaking when dropped, compared to US made tubes.
-All part of the tube mystique!


----------



## triod750

mordy said:


> I have noticed that Russian tubes are more resistant to breaking when dropped, compared to US made tubes.


I will challenge this. I will drop all my tubes and take notes. Did you ever compare to British made?


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## mordy (Nov 21, 2022)

triod750 said:


> I will challenge this. I will drop all my tubes and take notes. Did you ever compare to British made?





triod750 said:


> I will challenge this. I will drop all my tubes and take notes. Did you ever compare to British made?





From my tube graveyard collection - there are many more...
Marconi KTZ61 - died of unknown causes
Russian 6N51P - the nib broke off while in storage - note white residue of getter flash
National Union 6J5GT - dropped on floor
Valvo EL12 - defective, some internal problem causing unbearable hum. Glass broken for educational purposes - note dual circular getters and heavy duty internals


----------



## triod750

I have now dropped fourteen tubes and none broke. My bed might have something to do with it but there could be some other explanation    Experiments  will continue...
I had a delivery by the post of one Chatham 6AS7G and one Mullard 6080. The box was intact and they were pretty well packed. The innards of the Chatham had shifted to the side, almost touching the glass, and the tube was dead. (Still kept its vacuum). The Mullard is working perfectly. 6080 is a robust design.


----------



## mordy

triod750 said:


> I have now dropped fourteen tubes and none broke. My bed might have something to do with it but there could be some other explanation    Experiments  will continue...
> I had a delivery by the post of one Chatham 6AS7G and one Mullard 6080. The box was intact and they were pretty well packed. The innards of the Chatham had shifted to the side, almost touching the glass, and the tube was dead. (Still kept its vacuum). The Mullard is working perfectly. 6080 is a robust design.


During the good ol' days I bought three Chatham 6AS7G for not much money. During a photoshoot one rolled off my desk and broke. A second one gave up the ghost in use with no apparent cause. One left...
I assume that anyone using tubes for a while have similar experiences...


----------



## OctavianH

I was not able to remove for one week the GEC KT66 grey glass combined with Brimar 6SN7. This combo goes to my top 5.





I plan to make further comparisons of the KT66 clear vs grey glass but I need more time for that, most probably during winter holidays. I plan also to make further tests with EL156 which is an exceptional tube which was neglected by me due to lack of time. So I plan to put it into the lights again.

Other future plans? As always, something has to happen. Well, maybe some ECC40 or ECC808 on input and maybe some EL81, 4654K or EL39 on output.


----------



## mordy

OctavianH said:


> I was not able to remove for one week the GEC KT66 grey glass combined with Brimar 6SN7. This combo goes to my top 5.
> 
> 
> 
> ...


The problem with tube rolling is when you find that ideal combination that just leaves perfectly happy and satisfied - you don't want to switch the tubes any more.
For years you have been trying, and now you found it!
Something is wrong...You start to feel guilty that you did not try the other 2000 combinations that are possible based on all the tubes you have painstakingly collected over the years.
No more scanning eBay and other sources for unobtainable tubes where the prices go up every day...
No more reading about so and so trying those unobtainable tubes that you just must must have...

Boredom - how can I just listen to the music and enjoy it without wondering if...??

How is happy? - He who is satisfied with his lot


It never ends..


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## OctavianH (Nov 25, 2022)

mordy said:


> The problem with tube rolling is when you find that ideal combination that just leaves perfectly happy and satisfied - you don't want to switch the tubes any more.
> For years you have been trying, and now you found it!
> Something is wrong...You start to feel guilty that you did not try the other 2000 combinations that are possible based on all the tubes you have painstakingly collected over the years.


Exactly what I feel. I call it boredom but basically is not boredom. When you have the chance to listen to the same song in 3 ways and enjoy something from each way, then you'll miss the others while listening too much on a specific one.


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## triod750

OctavianH said:


> When you have the chance to listen to the same song in 3 ways and enjoy something from each way, then you'll miss the others while listening too much on a specific one.


Amen!! Tube rolling forever!!! And discovering. It's just another way to enjoy. It's not about right or wrong. It's much better


----------



## OctavianH

triod750 said:


> Amen!! Tube rolling forever!!! And discovering. It's just another way to enjoy. It's not about right or wrong. It's much better


One of the favourite topics on these forums is "burn in". Many say exists, others not and only our brain is adjusting. Well, quess what, my brain is also adjusting on different combos. After one week I do not perceive the combo in the same was as after a few hours. So well, maybe this is also a reason to change or try something else.


----------



## mordy

OctavianH said:


> One of the favourite topics on these forums is "burn in". Many say exists, others not and only our brain is adjusting. Well, quess what, my brain is also adjusting on different combos. After one week I do not perceive the combo in the same was as after a few hours. So well, maybe this is also a reason to change or try something else.


Absolutely! One of the things I find annoying is that once you get used to a certain combination and like it, after you change the tubes, and then go back to the first combination that you liked, it takes a while to appreciate it the same way ( and sometimes it doesn’t even happen…).
I also found that my amp sounds better at certain times, mainly on weekend nights. Perhaps there is less use of electric appliances etc that may cause electric interference.


----------



## jonathan c

mordy said:


> I also found that my amp sounds better at certain times, mainly on weekend nights. Perhaps there is less use of electric appliances etc that may cause electric interference.


…Then _for me_ there are times when, as much as I would like to listen, the headphone system sounds like wailing from Hades - emotional fatigue / a tough day have taken their toll. On those _rare_ occasions, I have to think “I’m done, some other time”. My ‘best’ listening sessions are the ones about which I am excited beforehand. 🤷🏻‍♂️


----------



## Isaacc7

OctavianH said:


> One of the favourite topics on these forums is "burn in". Many say exists, others not and only our brain is adjusting. Well, quess what, my brain is also adjusting on different combos. After one week I do not perceive the combo in the same was as after a few hours. So well, maybe this is also a reason to change or try something else.


What I think happens with me is that a new combo will seem to “click” but the longer I listen to it the more I am able to discern any shortcomings.


----------



## mordy

jonathan c said:


> …Then _for me_ there are times when, as much as I would like to listen, the headphone system sounds like wailing from Hades - emotional fatigue / a tough day have taken their toll. On those _rare_ occasions, I have to think “I’m done, some other time”. My ‘best’ listening sessions are the ones about which I am excited beforehand. 🤷🏻‍♂️


Yes, there are times when nothing sounds right…


Isaacc7 said:


> What I think happens with me is that a new combo will seem to “click” but the longer I listen to it the more I am able to discern any shortcomings.


Happens all the time to me - you start with a new combination, it sounds great, and then...you discover all kinds of things that you don't like.
It takes a long time to decide on what really is good and stays that way.
That is why I find it amusing when people say that they know in a few minutes how something sounds and make all kinds of pronouncements.
And the tube rolling trials to decide which tubes sound the best after listening in rapid sequence to a number of tubes for a couple of minutes each - I just don't trust those results...
(Another factor is that most tubes need some time to warm up and stabilize - often 1/2 hour to sound their best, and that is of course after burn-in which can take anywhere from 30 - 120 hours etc)


----------



## OctavianH

And to complicate things more, in my case some records sound better with a specific combo, other with another one. Depending on the mood, I listen to a part of my collection or other. So I have to adjust combos based on the category of records I am interested at that moment.

In my case, I had the feeling that tubes used by me and then abandoned for 1-2-3 years needed again time to burn in.

Of course, I agree with all the other remarks above.


----------



## OctavianH

Smallest outputs? Well, Sylvania 6V6GT. And a story about noise.






When I moved from Elise to Eternity I started to roll all my tube collection and found KT66 and 6V6 lacking bass in Eternity. I went more and more towards EL34 and 807. But a few weeks ago I had the chance to buy a pair of Wave Storm BNC cables to connect my TT2 with M Scaler. "Ok, so what?" you would say. Exchanging those digital cables between my upscaler and DAC made such a change in the overall signature of the line, adding bass and thickness to the sound, so now KT66 and 6V6 sound much  better. OK, they are still no match in terms of bass to EL34 or 807 but for acoustical instrumens and soundstage, well, these win. I am not trying to promote cables, nor summon the "Cable inquisition" to explain me that all cables are the same and so on, I just say a fact: I switched my existing cables to these and now 6V6 and KT66 sound different. This is our world, each link in the chain has unforeseen consequences on the overall performance of our whole chain. And this is how subjective are our remarks. Now think that each one of us has different ears, cables, DACs and so on...


----------



## mordy

OctavianH said:


> Smallest outputs? Well, Sylvania 6V6GT. And a story about noise.
> 
> 
> 
> When I moved from Elise to Eternity I started to roll all my tube collection and found KT66 and 6V6 lacking bass in Eternity. I went more and more towards EL34 and 807. But a few weeks ago I had the chance to buy a pair of Wave Storm BNC cables to connect my TT2 with M Scaler. "Ok, so what?" you would say. Exchanging those digital cables between my upscaler and DAC made such a change in the overall signature of the line, adding bass and thickness to the sound, so now KT66 and 6V6 sound much  better. OK, they are still no match in terms of bass to EL34 or 807 but for acoustical instrumens and soundstage, well, these win. I am not trying to promote cables, nor summon the "Cable inquisition" to explain me that all cables are the same and so on, I just say a fact: I switched my existing cables to these and now 6V6 and KT66 sound different. This is our world, each link in the chain has unforeseen consequences on the overall performance of our whole chain. And this is how subjective are our remarks. Now think that each one of us has different ears, cables, DACs and so on...


When I started with this hobby I did not think that it was possible to come to a consensus because of all the variables involved - equipment, personal taste etc but after a while I came to the conclusion that certain select groups of tubes have more of a universal appeal. In addition, I discovered that certain people hear things the same way I do, and that I could rely on their opinions (and the opposite lol).
My opinion at the time being is that the sound of a tube combination is amp dependent, but certain select tubes usually perform well in many different settings.


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## OctavianH (Nov 26, 2022)

Welcome to Dexter's lab. Today we write a new chapter in Eternity's history by trying KT61 on input. But let's start with the beginning.

What to do on a rainy morning? To measure. I received my 6V6 -> 6J5 adapters and tried my Sylvania 6V6 at Eternity's input operating point (180V, 4mA):





As expected 6V6 needs around -19V to work and I cannot use it on input. No problem, I knew that, just wanted to see with my own eyes. And now KT61.





Here things stand much more different. In 6J5 slots KT61 biases very similar with 6SN7. This means I can use these at my stock bias setting. Nice to know! I was lucky in the past to find the same for EL3N in 6J5 adapters at this specific operating point. So we are good to go, let's see what happens on Eternity.





One KT61 (the stronger one from the pair) goes at -6.2V (my stock bias setting) towards 4.7mA but we are still in the range or 3-5mA as advised by Tomas. The other is weaker, goes around 4.2mA. And that's at tube startup because it will decrease after tubes are heated enough, usually around 0.2-0.3mA. So I expect these in 1h at 4.5/4mA.

Excellent results! And now about the sound.





I was expecting a lower gain for KT61 in this configuration, so I was prepared to put my volume knob higher than for 6J5/6SN7 but surprisingly I keep it at the same level. Soundwise? Damn, KT61 kicks ass also in input position. Decently detailed with GEC flavour, a little bit more coloured than 6J5 ST shaped CV1067 grey glass. Sounds a little bit distorted, but is pleasing my ear, most probably because the tube is not in its linear zone in this scenario. And what is also surprising me is that pairing KT61 with KT66 does not make me feel too much "GEC goodness". I usuall keep only one GEC pair on the amp to avoid too much of that type of sweet sound. But these work nice together and do not really exceed my sugar allowed level. Good bass, good detail. This combo is a keeper.

And some nice words to our wizard craftsman Deyan which makes incredible adapters. Today he impressed me. Christmas came earlier.





Double adapters with rotating pin are looking sturdy and excellent.





But also single ones are nice.





We are lucky to  have him, excellent craftsmanship and a very flexible person. Having these I can try in the future even a quad of KT61 (both input output). As you can, most probably, see I have some pairs of double adapters and Eternity does not need that. Well, better safe than sorry, these would work on a possible upcoming amp with double triodes on input. Or if not, I have some spare parts. I can put now 6 tubes on Eternity, using double adapter on my 6SN7 slot.

That's all folks. A very rewarding day for me.


----------



## Isaacc7

OctavianH said:


> Welcome to Dexter's lab. Today we write a new chapter in Eternity's history by trying KT61 on input. But let's start with the beginning.
> 
> What to do on a rainy morning? To measure. I received my 6V6 -> 6J5 adapters and tried my Sylvania 6V6 at Eternity's input operating point (180V, 4mA):
> 
> ...


Wow! I thought I was king of adapters but you have me beat easily!


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## Isaacc7 (Nov 26, 2022)

Back from Thanksgiving holiday and so back to the music! Finally have the external supplies hooked up so can run 12v tubes. Currently running Tungsol BGRP 12sn7 and RCA branded 14c5.





This is the combo I envisioned when I realized I could use 12v output tubes. Rounding up, I have approximately one million 14c5 tubes. For whatever reason I acquired a lot of them 20 years ago or so and always wanted to hear them. They are labeled RCA but all of them are Sylvania. Despite the boxes all looking the same there are at least two different styles of plates in my collection. There could be more since a lot of them are so dark you can’t see the insides. All 7/14c5 tubes are loctal versions of Sylvania 6v6 tubes. These 14c5 have the flat edges on the plate. The JAN 7c5 I was using before had clear glass and the same oval plates as the Sylvania 6v6g. This particular input/output combo was meant to be the initial tube compliment but I had gotten the wrong length cables for the external supplies so used 6v tubes instead.

These tubes are giving me a different presentation than any of the others so far. Running them in triode and I’m getting a warmish, rich sound with a loose bottom end. Granted, I’ve only had them on for a couple of hours so I’ll give them a few days to settle in.


----------



## jonathan c

“Rounding up, I have approximately one million…” 😳🤔🤨… did you count? 😳


----------



## Isaacc7

jonathan c said:


> “Rounding up, I have approximately one million…” 😳🤔🤨… did you count? 😳


I gave up once I passed 20. Probably 40+ There’s no reason for it, just going wild on eBay. They’re probably worth about the same now as they were then, not much. I actually went crazier with 2e26 tubes. Not only do I have a ton of them NOS, I have approximately a million pulls for some reason. Sounds like I can actually run them like a 6v6 in triode so I’ll get some use out of at least 4 of them one of these days.


----------



## OctavianH

Isaacc7 said:


> Wow! I thought I was king of adapters but you have me beat easily!


Well, when I started to discuss with Tomas I wanted simplicity. 5 octal sockets, manual bias to accomodate natively 6V6/6L6/KT66/77/88/6550. On input all was looking good with single and dual triode sockets, natively 6J5/6C5/6SN7/6SL7/6N7. I thought I'll never want more. But you know, when you have the power it corrupts you. I started to read about 807, EL156 and so on. Then I had a few EL3N and 6F8G and so on. Then I read about novals... So in the end I unleashed the full power of Eternity via adapters.

This was my first lot. The one I posted before was the second one. Besides that I'll want EL39 and EL81 and after that I'm done. Or at least I hope so.






Ah, yesterday found in a box 2 x 6F8G -> 6SN7 I forgot about, so well, maybe I'll try some 6C8G because I never tried. It never ends, I am enslaved by flexibility. LOL


----------



## Isaacc7

OctavianH said:


> Well, when I started to discuss with Tomas I wanted simplicity. 5 octal sockets, manual bias to accomodate natively 6V6/6L6/KT66/77/88/6550. On input all was looking good with single and dual triode sockets, natively 6J5/6C5/6SN7/6SL7/6N7. I thought I'll never want more. But you know, when you have the power it corrupts you. I started to read about 807, EL156 and so on. Then I had a few EL3N and 6F8G and so on. Then I read about novals... So in the end I unleashed the full power of Eternity via adapters.
> 
> This was my first lot. The one I posted before was the second one. Besides that I'll want EL39 and EL81 and after that I'm done. Or at least I hope so.
> 
> ...


I have a few I want to get. I need another pair of 6bg6 to 6l6, gu50 to 6l6, 6av5 to 6l6, and 2e26 to 6v6. I think I will need a custom set of 2x6j5 to 6sn7 due to the spacing of my input tubes and the position of some adjustments on my amp. I might end up getting  2e22 to 6l6 at some point. Think I can use either 2e26 or 2e24 with the same adapter so that’s a possibility as well.


----------



## Isaacc7

Isaacc7 said:


> I have a few I want to get. I need another pair of 6bg6 to 6l6, gu50 to 6l6, 6av5 to 6l6, and 2e26 to 6v6. I think I will need a custom set of 2x6j5 to 6sn7 due to the spacing of my input tubes and the position of some adjustments on my amp. I might end up getting  2e22 to 6l6 at some point. Think I can use either 2e26 or 2e24 with the same adapter so that’s a possibility as well.


Will also get a 6gk6 to 6v6 adapter too. I have a bunch of GE 16gk6 and they are supposed to sound pretty good. A sane person would get an el84 to 6v6 adapter but I don’t want to get sucked into the expensive world of those tubes!


----------



## OctavianH

Isaacc7 said:


> Will also get a 6gk6 to 6v6 adapter too. I have a bunch of GE 16gk6 and they are supposed to sound pretty good. A sane person would get an el84 to 6v6 adapter but I don’t want to get sucked into the expensive world of those tubes!


You mean this world?



I would say cheaper than 6L6.


----------



## triod750

You really should try EL84. It's a very good tube!


----------



## Isaacc7

OctavianH said:


> You mean this world?
> 
> I would say cheaper than 6L6.


That’s not bad! I’m really more afraid of wanting to try all the different el84/6bq5 once I get into that world. I know me lol.


----------



## mordy

Isaacc7 said:


> That’s not bad! I’m really more afraid of wanting to try all the different el84/6bq5 once I get into that world. I know me lol.


Yes, I have the same fear - don't want to start with a new family of tubes so that I wouldn't have the urge to try all the variants...
And I have also become allergic to acquiring more adapters. Enough is enough. 

I am telling myself that I should try out all the possible combinations of all the tubes I already own.
Until...


----------



## triod750

Isaacc7 said:


> That’s not bad! I’m really more afraid of wanting to try all the different el84/6bq5 once I get into that world. I know me lol.


It would probably be a very rewarding experience


----------



## OctavianH

I tried in the last days to compare several Brimar 6SL7. I wanted to  understand if there is indeed a difference. I have 3 pieces, 2 of them being different only by the color of the base. So I tried the different ones:





The one of the left is older, but I have no idea about manufacturing date, the one on the right is from '72.





While both are very close and very nice sounding with RCA 807 on output, I have a feeling there is a slight difference, the newer one being an idea more clean and dry sounding while the older one is more natural. But as I said, both are very close sounding. The one on the right is labelled "CV1985" but I still prefer the other.


----------



## Isaacc7

OctavianH said:


> I tried in the last days to compare several Brimar 6SL7. I wanted to  understand if there is indeed a difference. I have 3 pieces, 2 of them being different only by the color of the base. So I tried the different ones:
> 
> 
> 
> ...


I have finally gotten around to trying the “Tungsram Made in UK” 12sl7. I put that in quotes Because I have an identical set of tubes but they are labeled “Brimar made in Holland.” I suspect they are all Philips tubes but have no way of knowing. 

I also have a set of 12sl7 that look just like your older 6sl7. Will get around to trying them in a bit.


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## Isaacc7 (Dec 4, 2022)

Finally!

To be honest, I was getting frustrated. I couldn't get a sound I was really happy with using 6v6 tubes. The best I could get was pleasant. No matter which input tubes I used or what mode/settings I used the sound just wasn't enjoyable over a few nights. Maybe Sylvania 6v6 and variants just aren't all that good? Time to try some different output tubes.

Next step was the 6aq5. Trouble was I couldn't find half of my adapters. Grrr... Ok, going down the low power list I decided to try the RCA 6f6. I already posted about how different they sounded in this amp as opposed to my other one. These had a lot more harmonic richness and maybe even lushness. The pattern of Ultralinear cleaning up the sound held true with the 6f6 too. Now to try to find some inout tubes to compliment them. Had my now standard Raytheon 12j5wgt in the preamp.

1) Raytheon T plate 6f8g solid all around, a bit mid forward but a that lent it a bit of "excitement." Solid bass but mid bass was lacking. Also not as open as I'd like.
2) Tungsram 12sl7. These gave back some clarity but the bass was noticeably weaker.
3) Mullard ecc31. I haven't had any luck with these tubes in either amp. They sounded the best I've heard with the 6f6 though. Smooth and balanced. Still sound thin though like they can't drive the output tubes.
4) The 2x6j5 to 6sn7 adapters fit perfectly though I can't adjust the main voltage with them installed. Moved the Raytheon 12j5wgt to the input position and put 14n7 tubes in the preamp. There's the open, clear sound I love so much and what I have come to expect from the Raytheons. But where's the bass? It was just... gone.
5) Put the Raytheons back into the preamp and put the 14n7 tubes into the input stage. Woo! That's the combo!

Edit to add I also tried the Tungsol BGRP 12sn7. Too thick, missing something on the high end, and even flatter soundstage. 

Now I have the clarity, openness, extended highs and lows and everything in between, and finally some depth to the image! It's the first time I feel like I can hear some of the hall with this amp. Going to run this combo for a few days. Will probably try the 7c5 or 14c5 with this combo of preamp and input tubes as well just to see if that has any magic.

I'm breathing a sigh of relief now that my system has gone from impressive to entrancing with this amp.


----------



## OctavianH

Isaacc7 said:


> To be honest, I was getting frustrated. I couldn't get a sound I was really happy with using 6v6 tubes. The best I could get was pleasant. No matter which input tubes I used or what mode/settings I used the sound just wasn't enjoyable over a few nights. Maybe Sylvania 6v6 and variants just aren't all that good? Time to try some different output tubes.


So you're struggling with 6V6 like I was in the beginning. I have to admit that 6V6 and even KT66 sounded weak on this amp and this is the reason I went for 807 and EL34. But it is curious enough that improving noise filtering on the rest of the line brought improvements making everything sounding warmer and bolder. Anyway, even now, these sound "delicate" on this amp, at least compared to the rest, and I start to have a feeling that old school designs have the same pedigree like new designs. So Odyssey shares something from the signature of Eternity. For my curiosity at which operating point are you trying these? Here at 200V/20mA.

In my camp everything is quiet, still on 807 with 6SL7 as last week.


----------



## Isaacc7

OctavianH said:


> So you're struggling with 6V6 like I was in the beginning. I have to admit that 6V6 and even KT66 sounded weak on this amp and this is the reason I went for 807 and EL34. But it is curious enough that improving noise filtering on the rest of the line brought improvements making everything sounding warmer and bolder. Anyway, even now, these sound "delicate" on this amp, at least compared to the rest, and I start to have a feeling that old school designs have the same pedigree like new designs. So Odyssey shares something from the signature of Eternity. For my curiosity at which operating point are you trying these? Here at 200V/20mA.
> 
> In my camp everything is quiet, still on 807 with 6SL7 as last week.


I run the 6v6 variants at 280v. Triode at 35ma and Ultralinear at 30ma. The lowest I can go is 250v. I'm running the 6f6 at the same settings to good effect. 

Really enjoying these RCA 6f6. At some point I will try the Ken Rad 6f6 as well. In my other amp I preferred the Ken Rad by a wide margin. That could have been because I thought the RCA sounded terrible lol.


----------



## OctavianH

I had in plan to try some 6F6 and also 6K6. Who knows, maybe I'll do it. In the meantime I try several 6LS7 with RCA 807. Basically rolling inputs. I guess these 6SL7 will be the following 6SN7 in the new tube designs, so I was lucky to gather a bunch of them to have enough my whole life. Today we live 6J5 times but I guess 6SL7 will soon come into attention. I've done the same with RCA807, I have enough to open a shop. LOL.


----------



## OctavianH (Dec 6, 2022)

Yesterday I discovered by mistake this one:






This is one 6N7 I never tried before because I was always associating it with an RCA grey glass one I already tried and it was as expected: warm and with RCA sound. Well, yesterday I said let's try this one and WOW, an excellent counterpart for RCA 807. This is definitely not sounding as I was expecting, it is thin but very detailed, excellent highs. So I started to investigate a little bit about the manufacturer, and except 5243 which is most probably the date code (43th week of 52) there is no "210" which I was expecting to find on a CBS / Hytron tube. But still, if I look to this one I find them similar.





And in order to see more inside, this one seems also the same:





So I found an RCA looking 6N7 which does not sound as other RCA 6N7. It seems I do not have to make any assumption anymore and just listen to all of them. We hear in 30 years when I'll finish. But there is one good thing which happened lately, I started to make an inventory and also nice photos of all my tube collection. This means from now on I'll easily find details about each one and maybe I will be able to compare and investigate more about them. The reason behind this was that some of the tubes I was using started to loose their paint and those markings are important. Other reason is that everytime I wanted to compare the construction with others I was too lazy to go to the storage and search for those. Of course, ongoing effort, but I've already added 47 tubes in it. Much more to go.


----------



## OctavianH

Looking inside, I was not able to decypher a lot but, here it is:


----------



## SonicTrance

Man, you guys are really taking advantage of the "tube rolling add-on" It's fun to see!


----------



## OctavianH

SonicTrance said:


> Man, you guys are really taking advantage of the "tube rolling add-on" It's fun to see!


Well, tube rolling is therapeutic, otherwise I look at these and my wallet is already under the bed shaking. )



Better to roll some 6N7 nobody cares about than to buy a new headphone. December is not helping either, "month of presents" LOL


----------



## mordy

OctavianH said:


> Yesterday I discovered by mistake this one:
> 
> 
> 
> ...


As you said, very often the markings wear off in use. When I get a new tube I try to examine it under a magnifying glass and then I write down all the information on a little piece of paper and attach it to the tube or tube box with a rubber band.
Usually I am able to decipher the markings and I write that down too, including the total purchase price. As long as I don’t lose that paper I have all the information about the tube readily available.


----------



## OctavianH

Just remembered I have somewhere a pair of Mullard EL32. Excellent sound from these with some 6SL7.


----------



## Isaacc7

Currently listening to 14n7 input with 5b/254m (807) output. Triode 320v 40ma.





As usual, the camera exaggerates the blue glow though it does look pretty good in the dark. Not pictured is the preamp using Cossor 6c5g. Initial impressions are good. The tubes have deepened and rounded out over the first couple of hours. I have a bunch of different 807 tubes and so will be cycling through them for the foreseeable future. I think the 6ar6 will be run at a similar setting as well but that will come later.


----------



## OctavianH

Nice, you taught me something. I see this for the first time. I expect these sound like 807.

By the way, let us know about 6AR6. I am also interested in them.


----------



## Isaacc7

OctavianH said:


> Nice, you taught me something. I see this for the first time. I expect these sound like 807.
> 
> By the way, let us know about 6AR6. I am also interested in them.


Everything I have ever heard about them said they are 807 tubes, just smaller. I wonder if the ones without the top cap have the same pin out as some other loctal tubes. The only problem with these is that they have a unique adapter much like the 6ar6.


----------



## OctavianH

Isaacc7 said:


> Everything I have ever heard about them said they are 807 tubes, just smaller. I wonder if the ones without the top cap have the same pin out as some other loctal tubes. The only problem with these is that they have a unique adapter much like the 6ar6.


By the way I remembered that there are 2 types of Tung Sol 6AR6: round plate and square plate. Round plate are older. Yours which type are? It would be nice to have both and compare. Picture taken from Ebay, you can see here both:


----------



## Isaacc7

OctavianH said:


> By the way I remembered that there are 2 types of Tung Sol 6AR6: round plate and square plate. Round plate are older. Yours which type are? It would be nice to have both and compare. Picture taken from Ebay, you can see here both:


Pretty sure they are the square type but have only looked at two. When I get to them I’ll take a closer look at what I have. Hopefully I have 4 off the same type!

I have swapped out the 14n7 with the ecc31. The 14n7 was just a bit more clarity than I could take  if that makes sense. I’m looking to warm things up a bit. The ecc31 are sounding better here than any other time I have heard them but they still sound thin. I will switch over to the cv1102 and then try the grey glass 14n7 and then if necessary some RCA 12sn7.


----------



## Isaacc7

Current configuration:





Same output tubes but now using Raytheon 12j5wgt x2 in place of the twin triode input. Still using the Cossor 6c5g in the preamp. Looks like I will need to get about quad of tbhose. Sigh and lol. 

Sounds amazing really. I now have the clarity, depth, and tonal richness I have been looking for. Seems like all the other combos I’ve tried with these output tubes were trad offs in some way but this particular one has it all. On the line hand it is great to have what I consider the platonic ideal of what a push pull amp should sound like. On the other hand it is sobering to think I won’t get any “better” sound than this but different flavors. In any case, I will keep this combo going till I leave for the Christmas holiday on friday. Will be gone for a week. I’ll continue the tube rolling adventure when I get back.


----------



## Isaacc7

I should add that this setup is amazing as long as you're listening to well recorded tracks. It can be unforgiving with so so or bad ones. So I guess finding another, more romantic" combo could be useful lol.


----------



## OctavianH

One thing that I have observed and mentioned several times on this thread is that these UltraSonic amps, while they are much better than what I was having before, are somehow more dependant on the source quality, rest of equipment and more unfogiving with the tube combination. I guess this is a common thing on high end products, but indeed, I feel the same as you that on this amp I need 3-4 good combos which are enough different between themselves to be able to cover all my music collection. This is the reason why I think twice at a possible Citadel build, because that will imply 3-4 combos of 2-4 pieces for each stage and might be problematic when one of the outputs is, for example GEC KT77 or who knows what rare tube I'll find in the future. My luck with Eternity was that it can use single double triode on input, so I was able to find used and decently priced a lot of nice ones like Brimar 6SL7 or Raytheon VT-231... Pairs of these cost like kidneys LOL


----------



## triod750

Dependant on source quality = transparent. And you need 'lesser' tubes to mask this. Or maybe tubes with different frequency response.
RCA 6BX7 with Adzam EL42 sounds smoky jazz club and all you hear is music. You don't care about technicalities. But after a while, a pretty long while, something creeps up on you and you have to change. And you get something else to enjoy. The beauty of tube rolling.


----------



## mordy (Dec 11, 2022)

triod750 said:


> Dependant on source quality = transparent. And you need 'lesser' tubes to mask this. Or maybe tubes with different frequency response.
> RCA 6BX7 with Adzam EL42 sounds smoky jazz club and all you hear is music. You don't care about technicalities. But after a while, a pretty long while, something creeps up on you and you have to change. And you get something else to enjoy. The beauty of tube rolling.


Regarding my tube amps I have noticed that a couple of them sound good with a lot of different tubes, but I have one amp that is very finicky and it takes a lot of effort to find the right combination of tubes. But when you get there, it sounds great…
Until you tire of that sound and start looking for something else….
The beauty (curse?) of tube rolling…
Over the years I have noticed that most people seem to continue to look for the “absolute” sound and a few people stop altogether and go to other pastures.


----------



## Isaacc7

OctavianH said:


> One thing that I have observed and mentioned several times on this thread is that these UltraSonic amps, while they are much better than what I was having before, are somehow more dependant on the source quality, rest of equipment and more unfogiving with the tube combination. I guess this is a common thing on high end products, but indeed, I feel the same as you that on this amp I need 3-4 good combos which are enough different between themselves to be able to cover all my music collection. This is the reason why I think twice at a possible Citadel build, because that will imply 3-4 combos of 2-4 pieces for each stage and might be problematic when one of the outputs is, for example GEC KT77 or who knows what rare tube I'll find in the future. My luck with Eternity was that it can use single double triode on input, so I was able to find used and decently priced a lot of nice ones like Brimar 6SL7 or Raytheon VT-231... Pairs of these cost like kidneys LOL





mordy said:


> Regarding my tube amps I have noticed that a couple of them sound good with a lot of different tubes, but I have one amp that is very finicky and it takes a lot of effort to find the right combination of tubes. But when you get there, it sounds great…
> Until you tire of that sound and start looking for something else….
> The beauty (curse?) of tube rolling…
> Over the years I have noticed that most people seem to continue to look for the “absolute” sound and a few people stop altogether and go to other pastures.


Finicky is a great word for Odyssey when it comes to tubes. With my other amp, a single ended pentode, most combos sound pretty good but with Odyssey some really don’t. But man, when you get a great tube combo and the right recording it is amazing.


----------



## Isaacc7

OctavianH said:


> One thing that I have observed and mentioned several times on this thread is that these UltraSonic amps, while they are much better than what I was having before, are somehow more dependant on the source quality, rest of equipment and more unfogiving with the tube combination. I guess this is a common thing on high end products, but indeed, I feel the same as you that on this amp I need 3-4 good combos which are enough different between themselves to be able to cover all my music collection. This is the reason why I think twice at a possible Citadel build, because that will imply 3-4 combos of 2-4 pieces for each stage and might be problematic when one of the outputs is, for example GEC KT77 or who knows what rare tube I'll find in the future. My luck with Eternity was that it can use single double triode on input, so I was able to find used and decently priced a lot of nice ones like Brimar 6SL7 or Raytheon VT-231... Pairs of these cost like kidneys LOL


I have another amp in mind that will use either single triodes or 6n7 tubes instead of the ubiquitous twin triode input. Not only are 6j5* noticeably cheaper but I have stumbled into a whole world of other single triodes and pentodes strapped as triodes. Any sane person would find a combo they like and just listen to music. But now I am accustomed to the thrill of the hunt lol.


----------



## mordy

Isaacc7 said:


> I have another amp in mind that will use either single triodes or 6n7 tubes instead of the ubiquitous twin triode input. Not only are 6j5* noticeably cheaper but I have stumbled into a whole world of other single triodes and pentodes strapped as triodes. Any sane person would find a combo they like and just listen to music. But now I am accustomed to the thrill of the hunt lol.


When it comes to 6J5GT tubes I can't think of any other tube with so many different variations in construction in addition to a host of rebrands - sometimes it is almost impossible to figure out who made it.
Among the reigning champions are supposed to be the GEC L63 and the National Union (silver top) 6J5GT7 but I like the Sylvania 1950's 6J5GT tall tubes as well.


----------



## Isaacc7

mordy said:


> When it comes to 6J5GT tubes I can't think of any other tube with so many different variations in construction in addition to a host of rebrands - sometimes it is almost impossible to figure out who made it.
> Among the reigning champions are supposed to be the GEC L63 and the National Union (silver top) 6J5GT7 but I like the Sylvania 1950's 6J5GT tall tubes as well.


I have been really happy with the Raytheon and National Union 12j5wgt tubes. Also loving the Cossor 6c5g. There really is a lot to choose from.


----------



## Isaacc7

Heh, I think of myself as an audiophile, keenly attuned to the subtleties of sound and performance. Noticed that one of my bias meters wasn't workin. Talking with Tomas he suggested one of the fuses had blown. Surely the tube wouldn't work if the fuse was blown? Yes, he said, you'll still get sound but less of it if the tube isn't working. Checked and sure enough one of the fuses was blown. Replaced it and swapped the offending tube. It does sound better now... lol. 

So two lessons; first of all I can miss big things sound wise. Second, it isn't crazy to have multiple tubes of the same type. One of the 5b/254m apparently went south. I had bought 10, 2 quads and 2 spares. Now I'm down to one spare.


----------



## Isaacc7

Turns out that having both tubes on one side working improves the sound, who knew! Really sounds lovely. The 5b/254m in triode push pull sound much better than they did in my single ended pentode amp. For the first time in a long time I don’t have the urge to try other tubes. Only problem with that is I have a ton of other tubes waiting their turn lol.


----------



## OctavianH

I've spent a few days with EL32 and now returned to KT66. I want to explore more from these in the context of my new discoveries on input. I have a feeling I might surprise myself trying some new combinations.


----------



## mordy

OctavianH said:


> I've spent a few days with EL32 and now returned to KT66. I want to explore more from these in the context of my new discoveries on input. I have a feeling I might surprise myself trying some new combinations.


ATM I am trying out new combinations with what I have and hoping to avoid buying more tubes lol.


----------



## OctavianH

mordy said:


> ATM I am trying out new combinations with what I have and hoping to avoid buying more tubes lol.


It happened not once that after buying more and trying more I realized I missed some from the previous existing collection, which were better. So, do not buy, just try. Sounds like a motto.


----------



## mordy

OctavianH said:


> It happened not once that after buying more and trying more I realized I missed some from the previous existing collection, which were better. So, do not buy, just try. Sounds like a motto.


DO NOT BUY - JUST TRY!
GREAT!!!


----------



## triod750

Try not to buy? Good luck!!


----------



## OctavianH

These brown bases of the british tubes are beautiful. I am addicted to them.


----------



## OctavianH

Very nice glow on this one, Tung Sol 6N7GT. And also good sound. Tubemaze seems to agree with me.


----------



## OctavianH

A few months ago I noted on my "best combo list" the GEC E3375 with the Tung Sol 6SU7. I have around 3 pieces marked as 6SU7 and one 6SL7. In my case I cannot distinguish a difference in sound between a grey glass 6SU7 and a grey glass 6SL7 (in photo below). I can distinguish however a difference between grey/clear glass.





I guess I'll search the storage for all 4 pieces and then try to listen to each one. As far as I remember all have different construction, but sound more or less the same.


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## OctavianH (Dec 21, 2022)

Ok, so I've done my homework and searched for my Tung Sol 6SL7 / 6SU7 / 6188. Here they are:


















The first 2 seem close in construction, at least from what I see. From the black glass one I have a pair. Last 3 are different. The mysteries of the Tung Sol 6SL7. First one, paired with some K-R 6L6GAY which I think has to be a Sylvania 6L6GAY sounds exceptional. Actually, it is the first time I enjoy a 6L6 on Eternity.





I have neglected all of these, so I'll have to dig more into them. Good that at least I found them and made an inventory. Soon I'll have all my tube collection pictured and I will be able to search and identify more of the ones I never really listened or knew who manufactured them. Because having decent pictures will help me compare, without opening the storage all the times. Welcome digital world. LOL

Later edit: Let's add also the ones on output:


----------



## Isaacc7

OctavianH said:


> Ok, so I've done my homework and searched for my Tung Sol 6SL7 / 6SU7 / 6188. Here they are:
> 
> 
> 
> ...


I'm surprised you haven't enjoyed the 6l6 in your amp seeing how much you like the 807. I would think all of the 6l6 family would perform well in your amp subject to differences between brands of course.


----------



## OctavianH

Isaacc7 said:


> I'm surprised you haven't enjoyed the 6l6 in your amp seeing how much you like the 807. I would think all of the 6l6 family would perform well in your amp subject to differences between brands of course.


Well, I have only 2 pairs of 6L6 and I think one of them is not quite an 6L6. One of the pairs is the above Sylvania one and I have some GE 7581A/KT66 like these. I tried the one above in the past, before discovering the 6SL7 and was not impressed. Well, it seems today things stand totally different. I doubt I'll try more 6L6 because the prices are much above 807 and honestly I think the Sylvania 5933, for example, is close to this pair of 6L6 and I have a quad of those bought around 50 EUR / pair. I'll not invest in the famous ones, better to go for unknown types. And yep, good test would be to compare these with 5933, but this means to dig again to storage and if I'll do that I'll also search for my pair of Sylvania 6CA7 to add to the comparison. I think all of these are nice, Sylvania 6L6/5933/6CA7 and not very far one from another.


----------



## Isaacc7

OctavianH said:


> Well, I have only 2 pairs of 6L6 and I think one of them is not quite an 6L6. One of the pairs is the above Sylvania one and I have some GE 7581A/KT66 like these. I tried the one above in the past, before discovering the 6SL7 and was not impressed. Well, it seems today things stand totally different. I doubt I'll try more 6L6 because the prices are much above 807 and honestly I think the Sylvania 5933, for example, is close to this pair of 6L6 and I have a quad of those bought around 50 EUR / pair. I'll not invest in the famous ones, better to go for unknown types. And yep, good test would be to compare these with 5933, but this means to dig again to storage and if I'll do that I'll also search for my pair of Sylvania 6CA7 to add to the comparison. I think all of these are nice, Sylvania 6L6/5933/6CA7 and not very far one from another.


The prices of the 6l6gc/7581a/kt66 have indeed gotten quite high. It's still possible to get good prices on the 807/5881/6l6/6l6g/6l6gb I think. I think the guitarists have driven up the value of the higher (voltage) rated 6l6gc but they seem to have forgotten about the others. I have a zillion 807 tubes as well as 6ar6 and 7581a. I might get a set of metal RCA 6l6 just to hear what the originals sound like. As always, the metal tubes have not appreciated in value despite their reputation for good sound.


----------



## OctavianH

Yeap, guitarists are bad guys but I have to live with them because I listen to them everyday with the tubes they use in their amps to record my music. I continued to work on my inventory, found some ugly ducklings, Sylvania 5932, and observed my pair contains round and square black plates. Well, no problem, I'll have to find a pair for each. I see that these are like those Tung Sol 6AR6 which had similar plates.








And the Sylvania 6CA7 I wanted to compare with 6L6.





MESA is a guitar amp right?





I'll have a lot of work to do during Christmas. When you will drink wine and sleep I'll inventory tubes and make comparisons. For me holidays are fresh air, I have time to do what I cannot do during normal months.


----------



## Isaacc7

OctavianH said:


> Yeap, guitarists are bad guys but I have to live with them because I listen to them everyday with the tubes they use in their amps to record my music. I continued to work on my inventory, found some ugly ducklings, Sylvania 5932, and observed my pair contains round and square black plates. Well, no problem, I'll have to find a pair for each. I see that these are like those Tung Sol 6AR6 which had similar plates.
> 
> 
> 
> ...


I had always heard that the 5932 was the octal version of the 5933. I knew there were some getter differences with different versions of the 5933 but never looked at the plates. I have a handful of 5933 and will look at the plates when I get home.


----------



## OctavianH

I tried a 1:1 between grey glass and clear glass Tung Sol 6SL7/6SU7. Indeed, grey glass ones are an idea warmer, a little bit veiled sounding and with mids an idea recessed. The difference is marginal but audible, and this is basically valid for all clear/grey glass tubes. Grey glass is more forgiving with that extra bass and rounder mids, polished somehow. In my case with these 6L6 which are already full bodied, the clear glass sounds more natural, transparent.





At this point it is fun to play with the gain switch, while rotating these 2. High impedance setting adds a little bit of bass, but does not sound so articulated. I have a feeling on these 6L6 the differences between low/high setting are more audible but I have no real explanation why. Interesting.


----------



## OctavianH (Dec 24, 2022)

The end of the year is coming, so I had to take a look on the leftovers. 2 of them were ECC88 and ECC188. I have only 2 pairs of these.









These are high gm, around 12mA/V, which means I have to be careful when adjusting the grid bias, the plate current varies by a lot at a small touch and even if you set these for 4mA at startup, the plate current will decrease much more than in other cases while tubes heat. This is what I was complaining about STC 12E1C which went around 4-5mA down during startup. Bias for me at 180V/4mA is around -5V for both and the sound, well, as I was afraid, seems nice but at the moment I just observe to be sure nothing unexpected will happen. I am a little bit afraid since I have a feeling that at a small touch these might jump a lot in current and I can do something stupid, but let's hope I'm just a noob and I'll get used with them.

Next try? I have somewhere a PCC189 and if I'll manage to find it I'll also try it in the amp today. After that 2023 can come, I am done for 2022. 

Later edit, the culprit:





This was designed for 7.6V heater but I was told it works fine at 6.3V and was used successfully as a 6922 replacement. Well, we'll see about that.


----------



## Isaacc7

OctavianH said:


> The end of the year is coming, so I had to take a look on the leftovers. 2 of them were ECC88 and ECC188. I have only 2 pairs of these.
> 
> 
> 
> ...


Most tubes' heater specs say they can be run at +/- 10% so running a 7.6 at 6.3 should probably be fine. 

I have read about the 12e1 running away. Don't remember the specifics but there is some talk about it over on the Diyaudio forum.


----------



## OctavianH

Isaacc7 said:


> Most tubes' heater specs say they can be run at +/- 10% so running a 7.6 at 6.3 should probably be fine.


Well, just measured it, quite unbalanced internally so I'll postpone trying it. I put the E188CC to see what's all about. Sounds more "technical" but I am not impressed, I liked more the lively sound of the E88CC.


Isaacc7 said:


> I have read about the 12e1 running away. Don't remember the specifics but there is some talk about it over on the Diyaudio forum.


My STC 12E1C worried me a little bit because the plate current decreased a lot during first 30mins, so I had to adjust several times the grid bias. The GEC 12E1 never had any problem, those worked well and do not behave like the others. I doubt I'll ever try other type so... fine for me.


----------



## OctavianH

Christmas, everyone is decorating everything, so I've decorated Eternity.





I prefer to have trees alive in the forest, so that's all for me.


----------



## OctavianH

I tried the Sylvania 5932 this morning. I was expecting to bias them similar with 807 or 5933 around -18.5V but these were stronger, went around -21V.





Soundwise close, I have a feeling the left one with side getter sounds a little bit muffled compared with the other one from right channel but it might be all in my head.


----------



## OctavianH

One year of D8000 Pro. Eternity and D8000 Pro remained my partners in crime for a year. I never looked for other headphone, I've sold or gave the ones I had. No regrets. If someone will ask me how D8000 Pro sounds, well on Eternity is organic and natural. That's it. It is definitely a warm headphone, not quite sounding like a planar, somehow in the middle of dynamic and planar headphones. Best of both worlds, just like Eternity, a modern design, flexible which is in the middle of tubes and solid state. Neutral, fast, detailed, wide sounding. And you can put almost anything on it, not the most expensive tubes. I am lucky.





This combo of ITT Lorenz (Siemens) E88CC and the Sylvania 6L6GAY is incredible. And each hour passes it gets better and better.


----------



## UntilThen




----------



## OctavianH

Gorgeous picture, next year we will have one with Telemachus.


----------



## UntilThen

OctavianH said:


> Gorgeous picture, next year we will have one with Telemachus.



Waiting in anticipation.


----------



## OctavianH (Dec 25, 2022)

Just read this and saw a Susvara in Classifieds. Santa, you're playing with me.

Later edit:
More goodies there: Abyss 1266 Phi TC, Utopia and D8000 Pro LE. Damn, keep you wallets safe guys. LOL


----------



## UntilThen

OctavianH said:


> Just read this and saw a Susvara in Classifieds. Santa, you're playing with me.
> 
> Later edit:
> More goodies there: Abyss 1266 Phi TC, Utopia and D8000 Pro LE. Damn, keep you wallets safe guys. LOL



All very nice headphones but for now I will use what I have. The Grado is surprisingly very enjoyable with Odyssey. So sweet !


----------



## UntilThen

Octavian, let the tube rolling begin.


----------



## triod750

OctavianH said:


> One year of D8000 Pro. Eternity and D8000 Pro remained my partners in crime for a year. I never looked for other headphone, I've sold or gave the ones I had. No regrets. If someone will ask me how D8000 Pro sounds, well on Eternity is organic and natural. That's it. It is definitely a warm headphone, not quite sounding like a planar, somehow in the middle of dynamic and planar headphones. Best of both worlds, just like Eternity, a modern design, flexible which is in the middle of tubes and solid state. Neutral, fast, detailed, wide sounding. And you can put almost anything on it, not the most expensive tubes. I am lucky.
> 
> 
> 
> This combo of ITT Lorenz (Siemens) E88CC and the Sylvania 6L6GAY is incredible. And each hour passes it gets better and better.


If you like that E88CC then this would be absolutely essential:





https://www.ebay.co.uk/itm/265056968235


----------



## OctavianH

Hmm, seems too cheap for me.


----------



## triod750

You could tip him off with a couple of hundreds....


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## OctavianH (Dec 27, 2022)

UntilThen said:


> Octavian, let the tube rolling begin.


I guess it should. Looking at this one:









Found a remark here. J8 = September 1948? (not sure if I was part of these, if it was it's October)

Later edit: I see these bias the same as ECC32/6N7. In my case -3.3V for 180V/4mA.


----------



## gibosi

OctavianH said:


> I guess it should. Looking at this one:
> 
> 
> 
> ...



Mullard didn't begin to use the Philip's production code until around 1955. Before then, they used their own system. And unfortunately, I have yet to find the key. And I don't see any patterns to allow reasonable guesses. For example, an NU12 rectifier is "54BH" and an ECC31 is "1029.1 1MV." So the only thing this code tells me is it was manufactured before 1955. But judging by construction, it is probably after WWII, and 1948 is as good a guess as any.


----------



## Isaacc7

The STC 5b/254m with Raytheon 12j5 input tubes is a magical combo in my amp. Big, solid, involving, and rich. Honestly I could live with that sound forever. But with so many other tubes waiting I feel like I need to try something else.

Popped in the Cossor 807/vt60 and kept the same operating specs (triode, 320v, 40ma) and was very impressed. They have maintained the clarity and openness I heard in the single ended pentode amp. That's a relief because I bought... more than a few. The increased clarity allowed me to hear more of the room and put the performers farther back in the soundstage. The Cossor sound more transparent and clear allowing subtle things to come through. Listening to the remaster of Julian Bream's Classics for Spanish Guitar I could distinctly hear the strings vibrating as well as the resonance of the guitar body as separate sources. It made it that much more realistic from an imaging standpoint. Putting him back bit in the soundstage also made it feel like a more accurate portrayal of the guitar as well. Most of the tubes I have used have brought the guitar foreward and made it seem too big. The single ended pentode amp is the biggest offender in that category. With the Cossor 807 the guitar is in better focus and the scale is right. Lost that a bit with the 6f8 tubes though. 

Alas, with the Raytheon 12j5wgt input tubes there is a bit of high midrange glare. And so the hunt was on for some more compatible inputs for the Cossor 807. First tried the cv1102/BL63. They made the sound dry for lack of. better word. Also seemed to compress everything. Currently using my trusty Raytheon T plate 6f8g and am enjoying the sound quite. bit. I am missing that clarity I had from the last set though. I will try some more single triodes. My tubes were neatened up and so it isn't real obvious where my 6/12j5 stash is lol. I'm thinking either the Aussie Radiation 6j5gt or maybe the NU 12j5wgt might give me what I'm looking for. Eventually I will have another quad of the Cossor branded 6c5g tubes to put in there. I love them in my preamp but I bet they would also be the cat's meow in the amp. Gotta take care of some car stuff first though.


----------



## Isaacc7

I’ve now got my equally trusty tall bottle 14n7 in for the inputs. They’ve back some of the detail/depth I was missing with the Raytheon 6f8g without the slight glare of the Raytheon 12j5wgt. Whenever I use the 14n7 I am impressed by the solidity of the lower midrange and bass. It just has more impact. Think I’ll coast with this combo for a little while, sounds quite good.


----------



## triod750

You have probably compared this to 7N7, I don't remember. What is the sonic difference, if any? And manufacturer (not brand)?


----------



## Isaacc7

triod750 said:


> You have probably compared this to 7N7, I don't remember. What is the sonic difference, if any? And manufacturer (not brand)?


All of the 7n7 and 14n7 were built by Sylvania regardless of brand. The one exception is the rare round plate 7n7 that was made by National Union. I’m convinced that the clear glass 14n7 is the same tube as the metal base 6sn7w. Both the tall and short bottle 14n7 have the same copper support rod and more textured plate like the 6sn7w metal base. When I compare similarly made (short or long bottle, same kind of getter silver) the 14n7 has better clarity, bass, and imaging. I can’t tell any difference between the short and tall bottle 14n7 whereas I think the tall bottle 7n7 is noticeably better than the short even with the same plate structure. 

There are also grey glass 14n7 but I haven’t had much luck with them. They are noisy and end up sounding grainy and annoying in general. I have more than a few of every version of the tubes mentioned and have generally felt that they are consistent in how they sound.


----------



## gibosi

Isaacc7 said:


> All of the 7n7 and 14n7 were built by Sylvania regardless of brand. The one exception is the rare round plate 7n7 that was made by National Union. I’m convinced that the clear glass 14n7 is the same tube as the metal base 6sn7w. Both the tall and short bottle 14n7 have the same copper support rod and more textured plate like the 6sn7w metal base. When I compare similarly made (short or long bottle, same kind of getter silver) the 14n7 has better clarity, bass, and imaging. I can’t tell any difference between the short and tall bottle 14n7 whereas I think the tall bottle 7n7 is noticeably better than the short even with the same plate structure.
> 
> There are also grey glass 14n7 but I haven’t had much luck with them. They are noisy and end up sounding grainy and annoying in general. I have more than a few of every version of the tubes mentioned and have generally felt that they are consistent in how they sound.



And just to be clear, the 14N7 is the 12-volt version of the 7N7.


----------



## Isaacc7

Or if I’m to be believed, the 14n7 is the 12v version of the metal base 6sn7w. IOW I think the 14n7 is different than the 7n7 in more ways than just the heater.


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## OctavianH (Jan 5, 2023)

I was not very active in the last days, but today I measured and tried some Mullard EL32 grey straight glass and some Brimar 6N7GT. Brimars went around -3.7V both (with triodes in parallel 2mA each), stronger that average 6N7G which goes around -3.3-3.5V. Mullard EL32 went around -16V.

Here Mullard EL32 with some Brimar 6SL7GT. It's a coloured sound, but catchy. It's not linear or natural, it's wrong, but the wrong you like to keep close to your ears. LOL






EL32 has M02 / B4K1 on it as codes.


----------



## triod750

OctavianH said:


> but the wrong you like to keep close to your ears. LOL


This is a truth to behold, with some combinations. Enjoyable. To enjoy is right, not wrong.


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## OctavianH (Jan 6, 2023)

Today I go to the Dark Side. They have cookies. Goodbye Eternity and tubes, goodbye interconnect cables.





Today we will have:
D8000 Pro with stock silver plated cable
TT2 + M Scaler fed by JCAT Femto USB XE directly from PC (ASIO)
Wave Storm dual BNC cables
Kimber Kable USB silver (blue coated one)
LPS filtered for JCAT/TT2/M Scaler (Sbooster for JCAT, MCRU for Chord pieces)
Foobar2000 V2 (Beta 20)

No more tubes, amps, interconnects. My life has just simplified. I'll return to classifieds to sell Eternity and then transfer this thread to Isaac. LOL

Let's see where this goes.

PS. I wanted for a long time to evaluate again the SS situation. I planned to do this extensively with D8000 Pro, but never resisted more than 30 mins. Now with Wave Storm dual BNC which provide a fuller sound and more detail, I'll try again.


----------



## triod750




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## OctavianH (Jan 6, 2023)

Friday Beerday! A good moment to drag some conclusions about one day with a solid state amp. I am not trying to convince anyone, but for me TT2's integrated amplifier is no match for Eternity. And I'll try to explain.

But first one more thing, this TT2 starts to sound decent after a few hours of usage. If it was turned off then you need a few hours to let it run until the harshness will go away and the timing will start to be closer to expectation. At first you hear a harsh chaos. I turned it on around 9 AM and only around 13 PM I started to understand something. And this is happening also if you are using it in DAC mode. So the idea is to keep it always on as many are doing with different type of DACs around here. Well, I couldn't do it, since I wanted to plug headphones and switch from AMP -> DAC mode and I had to restart it.

Now, another thing is that I am able to listen to D8000 Pro directly on TT2 only with the stock cable, the FAW Noir Hybrid has XLR connector and I have no pigtail/adapter for that. This means, I can compare the sound only with this cable.

But even in this case, after around 4 hours of usage when TT2 improved and became to sound better and better, most probably because of clock calibration or whatever was happening inside of it or in my brain, TT2 remained maybe an idea tighter sounding than Eternity but also narrower. But it also sounded brighter than Eternity, more in your face because of the soundstage which honestly feels like colapsed. Even instrument separation seems worse for me because everything seems condensed. On Eternity you get the detail somehow layered and placed in different areas, here everything comes more or less in your face. Anyway, I guess the thing which frustrates me the most using this TT2 integrated headphone amp is that the timbre is not so natural as on Eternity. It is fast, it is tight, seems detailed, at the same level or maybe a slight idea more, but sounds like a recording. Eternity is more towards a live concert for me. My guitars are drier, lifeless, more synthetic and artificial sounding. I said I can try to use some filters (TT2 has 4 distinct filters and I usually keep it on incissive neutral all the time) but they were for me, more or less, the same. Then I said to play with upsampling ratio from M Scaler. Indeed, the upsampling to maximum I got a more precise and an idea more natural sound, but still, the same problems remained. So now what? These are all my options. On the other amp I was able to play with one combo or the other, here most probably I have to start with software equalizers. Well, not for me.

So I switched back to Eternity, using the same headphone cable and imediately the life was back in my ears. A more rounder, wider and warmer sound. Everything is somehow now layered, better separated and what's most important, more natural. It might be rounder and an idea more forgiving but in the end this is not a big problem for me. And now I have my 100 possibilities to tune this and listen to the song in so many ways. Tube amps, bringing emotion back in music.

Wave Storm dual BNC made TT2's integrated amp sound fuller and less harsh, but they did not solve the other problems. I remember that last time I tried it I had a worse impression than today. So I still think they are a must if you own this combo.

Well, I guess I'll postpone my visit to the Classifieds, Eternity is here to stay. I think that also Elise was closer to my preferences than TT2's integrated amplifier and I remember that I compared them both when owning it. So 10 hours with an SS amp did not convince me. I am fully convinced there are better dedicated amps, but I do not plan to invest  time or money to find them. I actually plan to research and see if I can find a standalone DAC solution which will be better for me than this one, because I use only a small part of its features and the annoying part of turning off/on and then waiting for a few hours to stabilize is definitely not pleasant. Maybe look into these R2R DACs everyone praises. Anyway, not a priority, we can let here TT2 on forever and the problem is solved.

Good, now it's time for a beer and soon I'll switch back to my FAW Noir Hybrid cable which for me sounds better than this stock one.


----------



## triod750




----------



## OctavianH

triod750 said:


>


I am unsure if you are happy that my life remained complicated or not.


----------



## Isaacc7

OctavianH said:


> Friday Beerday! A good moment to drag some conclusions about one day with a solid state amp. I am not trying to convince anyone, but for me TT2's integrated amplifier is no match for Eternity. And I'll try to explain.
> 
> But first one more thing, this TT2 starts to sound decent after a few hours of usage. If it was turned off then you need a few hours to let it run until the harshness will go away and the timing will start to be closer to expectation. At first you hear a harsh chaos. I turned it on around 9 AM and only around 13 PM I started to understand something. And this is happening also if you are using it in DAC mode. So the idea is to keep it always on as many are doing with different type of DACs around here. Well, I couldn't do it, since I wanted to plug headphones and switch from AMP -> DAC mode and I had to restart it.
> 
> ...


That was quite a ride lol. 

I will say that it is very possible to have good sound with a solid state rig. On top of that I think that for people that aren’t interested in gear or its possibilities a good solid state amp is the way to go. I do think tubes sound better in general but I could very well settle with a single tube combo and be happy from a sound perspective. I do enjoy tubes and fiddling with them so much though. I love taking 80 year old tubes out of their packaging and experiencing sound from the dawn of the electronic age. And I love finding that magic combo that just captivates you. Here’s my current blissful situation. 





Cossor/Mazda vt60a outputs (triode, 320v, 40ma) with Tung Sol BGRP 12sn7 inputs. Preamp is using Cossor branded 6c5g. Sweet tone with good heft. Not quite as detailed as the 14n7 but there is a purity of tone that is hard to describe. Sweet is about as close as I can get. I think it’s worth getting a 12v option on your amp just to be able to afford the BGRP Tung Sol tubes. The 6sn7 version has gotten a bit out of hand price wise. You can get the 12v for around $100, probably less if you’re patient. There aren’t any tubes that are great with every other tube/system but these Tung Sols can be magic With the right combo.


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## triod750

OctavianH said:


> I am unsure if you are happy that my life remained complicated or not.


I like that your life and adventures remain interesting. Solid state of life; how interesting is that?
But to each his own. I know of a person who invested a couple of fortunes in audiophile equipment without any happiness rewarding him. He god rid of everything and now has a very simple and cheap setup and just three records. He listens to them every day and says he is happy while his girlfriend is going crazy...


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## Isaacc7

Oh man, I need to get off the internet. Currently looking into more adapter possibilities and I'm getting a little far afield. In addition to the numerous adapters I already have I'd like to get gu50, 6av5, 2e22, 2e26/4 for power tubes. I'm getting kind of weird for input tubes. The 6c5 is a 6j7 triode wired so why not get some adapters to do that? I have a smattering of those already. Also idly wondering if a 2x triode wired 6aq5 instead of 6sn7 is worth doing... The sickness never really goes away lol.


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## OctavianH (Jan 7, 2023)

I also received some nice adapters from Deyan for EL81, EL84 and EL39. I was curious to check EL81 which is used in Oblivion because the prices are quite good. EL84 is, on the other hand, much more expensive, and I think I went wrong on that path. EL39.. well it had to be done. 6J7 on my 6J5 slots should be interesting, I see that it biases close to 6J5. Maybe I'll try that in the future.

I like a lot these ceramic noval sockets and also the flexible wire used for top caps.


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## Isaacc7

OctavianH said:


> I also received some nice adapters from Deyan for EL81, EL84 and EL39. I was curious to check EL81 which is used in Oblivion because the prices are quite good. EL84 is, on the other hand, much more expensive, and I think I went wrong on that path. EL39.. well it had to be done. 6J7 on my 6J5 slots should be interesting, I see that it biases close to 6J5. Maybe I'll try that in the future.
> 
> I like a lot these ceramic noval sockets and also the flexible wire used for top caps.


If the 6j7 triode wired is the same as a 6c5 then they should bias up exactly like a 6j5. The el84 does have some expensive tubes but they really aren’t that bad yet compared to the big pentodes. 6bq6 are the same but American, some are very well regarded. Of course if you want to play with American 6bq5 cheaply you’re better off getting adapters for 6kg6, same tube but a different pin out. I have some 16gk6 from GE. If the reviews of the equivalent 6bq5 are to be believed then they are supposed to sound pretty good. I’m not sure if I want to go down that path, I have enough adapters on the brain as it is lol.


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## OctavianH

Guys, if you understand and know more than me correct me. An interesting point of view was done on Oblivion thread related to EL81 usage on Eternity. As far as I understand, it has to work with bias around -40V and I will explain how I determined that. Because I could not find a triode connection graph I saw this:





In this datasheed of Mullard EL81 it is mentioned that EL81 connected in triode mode (G2 -> A, G3 -> K) provides 40mA at Vplate 250V and Vgrid1 -38V. My Eternity can go lower as -54V on Vgrid. But my Vplate is 200V (so current should be lower). Let's assume I want to have 20mA on Vplate 250V as in the table. Because gm is 5.5mA/V I expect that decreasing Vgrid with 1 Volt I loose 5.5mA as current. Am I right? I know gm is plate current variation at grid voltage variation. This means that 20mA would mean -4V more (4x5.5 aprox = 20mA I want to decrease). If I am not wrong, EL81 should be around 20mA with grid bias -42V and Vplate = 250V. On Eternity at Vplate 200V I guess current will be smaller, so maybe -40V grid?

I am a noob, I have no real understanding of these parameters but this is how I somehow imagine these work in my head and based on what I have played with my tube tester. In short words, is my logic of determining an approximate grid bias right? This is how I thought when I decided to go towards EL81 -> KT88 adapters and try this. I basically applied mathematics over some data from these datasheets, but for sure, things are much more complex in real life. Another parameter I always look is recommended/maximum Vplate which has to be above 200V if I decide to use a tube (this is why EL82 for example with 200V is at the limit for me and I'll never try it).


----------



## Isaacc7

OctavianH said:


> Guys, if you understand and know more than me correct me. An interesting point of view was done on Oblivion thread related to EL81 usage on Eternity. As far as I understand, it has to work with bias around -40V and I will explain how I determined that. Because I could not find a triode connection graph I saw this:
> 
> 
> 
> ...


I can’t say anything meaningful about your logic but I will say that figuring out what operating points a pentode wired as a triode should use isn’t super consistent. It’s great when we have specs for it as shown here though you have the be a little careful about the context. I’ve seen some specs for triode operation that show absurdly high numbers. This happens a lot with tubes designed for TV use. The really high triode limits are specced for bursts, not continuous. For whatever reason, some tube’s triode operation point is constrained by the limits of the screen grid while others can go way over. I had naively assumed that since the screen and plate were tied together you could average out the limits to get the triode operating limit. It turns out that some tubes have “greedy” screens and will still suffer if you go over the pentode screen limits. Others allow you to go way over the screen limits. I’m still looking into this for tubes that are being repurposed to audio uses like the 6ar6 and el38.


----------



## Isaacc7

Still listening to the Cossor vt60a outputs but have been mixing up the input tubes. Went from the TS BGRP to the Tung Sol 6c8g. Mostly sounded similar but perhaps a little cleaner. Then I remembered I had gotten in some fancy 12sl7 tubes a while ago. Tried them in my old amp but it just doesn’t like *sl7 tubes. Put them away and waited for the Odyssey, then forgot about them lol. 

First up is the Brimar 12sl7. 





Uh oh, really low volume on the left side and then BRRRTSH! Jumped up and shut down the amp. Sigh, bad tube. I will eventually get another. The CV1985 is essentially Brimar’s 6sl7 and it has a great reputation. The 12sl7 should have at least a family resemblance. Ok, next up is the Tungsram 12sl7. 





I have 3 of these and another identical tube labeled Brimar “Made in Holland.” I wonder which one is lying? In any case these sound amazing with the vt60a. Still have the super strong lower midrange but now with extra clarity As compared to the Tung Sol tubes. The midrange is slightly forward now which makes for great vocals. I think these are close to the 14n7 in some ways but these have just a bit more detail and richness. Will stick with these for a bit and will eventually try the 5b/254m with them as well. 

I’m finally going back to work tomorrow. Been out for almost 6 months with the after effects of Covid Won’t be doing as much listening of course so updates might be a little more sparse than they have been. I can say that my stereo has kept me sane while mostly being confined to home. Thanks @SonicTrance for helping out!


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## OctavianH (Tuesday at 2:32 AM)

Isaacc7 said:


> I have 3 of these and another identical tube labeled Brimar “Made in Holland.” I wonder which one is lying? In any case these sound amazing with the vt60a. Still have the super strong lower midrange but now with extra clarity As compared to the Tung Sol tubes. The midrange is slightly forward now which makes for great vocals. I think these are close to the 14n7 in some ways but these have just a bit more detail and richness. Will stick with these for a bit and will eventually try the 5b/254m with them as well.


That Brimar 12SL7 looks identical with my 6SL7 and it is, indeed incredible. I prefer it to the "CV1985" labelled brown base I have which is newer production. Mine has D-getter while the other has O-getter. I'll repost the pictures to clarify.









Besides these, I have a black base white print 6SL7 which looks internally identically with the brown base one.





You are on big horses there, Brimar 6SL7 is incredible. And I tried also the 6N7 and was very nice.
I'll try to explain the difference between the first one and the other 2. The newer production sounds drier and maybe an idea more precise, while the older one is more vivid and lively. Maybe to get an idea you can think on KT66 grey glass vs KT66 clear glass. For me it is the same difference. This is why I consider GEC for example having 2 periods of signature: older ones like my ATS25 or GEC grey glass which are an idea warmer, more air while the newer ones are drier and maybe cleaner sounding in detriment of a natural sound. Newer ones are an idea forced for me. Anyway, another thing I observed is that this dry sound of the newer british tubes is accentuated if you use silver interconnects like mine. What I try to say is that the whole chain has to be considered a part of the signature. Headphones, cables, DAC, amp and so on. On copper interconnects I am sure the newer GEC sound more natural, but highs are not that clean.


----------



## Isaacc7

OctavianH said:


> That Brimar 12SL7 looks identical with my 6SL7 and it is, indeed incredible. I prefer it to the "CV1985" labelled brown base I have which is newer production. Mine has D-getter while the other has O-getter. I'll repost the pictures to clarify.
> 
> 
> 
> ...


I’ve heard nothing but good things about the Brimar. I was also under the impression that the 6sl7 and cv1985 were the same tube just labeled differently. I think you can find tubes that look like the older 6sl7 labeled cv1985. I’ve heard similar things about the Brimar 6sn7 but those are wayyyyy too expensive these days. Looking into the 13d1 in hopes of capturing some of that magic.


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## OctavianH (Tuesday at 11:07 AM)

Isaacc7 said:


> I’ve heard nothing but good things about the Brimar. I was also under the impression that the 6sl7 and cv1985 were the same tube just labeled differently. I think you can find tubes that look like the older 6sl7 labeled cv1985.


I think that CV1985 is the same tube as 6SL7 but under british naming scheme. The difference comes from construction and manufacturing period.


Isaacc7 said:


> I’ve heard similar things about the Brimar 6sn7 but those are wayyyyy too expensive these days. Looking into the 13d1 in hopes of capturing some of that magic.


What I have here is this 6SN7:





And a pair of these 6N7:





If you ask me, I like more Brimar 6SL7 than Brimar 6SN7, but it is true that in general I like more any 6SL7 than any 6SN7 so... About Brimar 6N7 I do not have yet an opinion since I barely used them, They were, of course, nice. I will spend more time with them in the coming weeks.


----------



## OctavianH

Ok, let's try a nice one this evening. ATS25 + ECC33. I guess from ECC31/32/33/35 these are my favourites until now. ECC34 is missing from my collection.


----------



## Isaacc7

Talking with one of my usual tube suppliers has filled me with FOMO. So, uh, YOLO I suppose. I promised myself in October I wouldn't order any more tubes that year. Well, it's a new year... lol. Just placed an order for some 13d1 tubes and another b36 to match the one I already have. Have another sizable order in the works, mostly all input tubes. The one power tube I will order is some Brimar 6bg6 and possibly a quad of GE 6bg6a. Those are cheap enough that I figured what the hell, might as well throw them on the pile. 

I know I've said it before, but I really think I will be done after that. Not sure what else there is to get. Well, other than the adapters I need to use some of the tubes I have now and the ones that will be coming. I have an idea for another amp, a parallel SE pentode amp. Once my tax return comes in I'll ask Dennis Had if he's interested in doing it. 

I am convinced the tube apocalypse is nigh. The supplies of really desirable tubes are finally drying up. Guess I'm a tube survivalist lol. I already have enough for several lifetimes. Will need to start paring down the tubes I know I can't/won't use and there are a bunch of them. In theory, I will be able to stop my amp related audio buying and turn to other more practical uses of my money. You know, something sensible like modular synthesizers or something lol.


----------



## OctavianH

Isaacc7 said:


> Talking with one of my usual tube suppliers has filled me with FOMO. So, uh, YOLO I suppose. I promised myself in October I wouldn't order any more tubes that year. Well, it's a new year... lol.


You see, that's the first mistake: never speak with your usual tube suppliers. LOL


Isaacc7 said:


> I know I've said it before, but I really think I will be done after that. Not sure what else there is to get. Well, other than the adapters I need to use some of the tubes I have now and the ones that will be coming. I have an idea for another amp, a parallel SE pentode amp. Once my tax return comes in I'll ask Dennis Had if he's interested in doing it.


If I'll ever want another amp, it has to be different than Eternity. So I guess the balanced Citadel with tube rolling and 12/6V heaters remains on the table.


----------



## Isaacc7

Finally put in the Miniwatt branded made by Fivre b36 tubes along with the 5b/254m outputs. Immediately ordered 2 more pairs! What an amazing combo! And they weren’t all that expensive really… Glad I jumped on buying them, who knows the next time I’d see some. I’ll have some MOV made b36 soon, will be interesting to compare.


----------



## jonathan c

…no wonder… ‘out of stock’ … Langrex … 😒


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## OctavianH (Yesterday at 3:21 AM)

Isaacc7 said:


> Finally put in the Miniwatt branded made by Fivre b36 tubes along with the 5b/254m outputs. Immediately ordered 2 more pairs! What an amazing combo! And they weren’t all that expensive really… Glad I jumped on buying them, who knows the next time I’d see some. I’ll have some MOV made b36 soon, will be interesting to compare.


If 5b/254m has more or less the same electrical specs of 807 I expect these B36/B65 sound good also with them. When I'll order my Citadel with 12.6V heaters option I hope you will be nice enough to send me a box of tubes, since you bought all internet.

I am here still on the same ATS25, this time with 6N7. I can live with this my whole life but I know I'll get bored soon and change it.


----------



## Isaacc7

jonathan c said:


> …no wonder… ‘out of stock’ … Langrex … 😒


To be fair, there were only 5 left, that’s why i jumped on them before they were gone. A fellow head-fier bought the last one. I had bought a pair 4 months ago or so and there were a lot more of them then. Glad I satisfied my curiosity about the stock level otherwise might have missed out on them altogether.


----------



## Isaacc7

OctavianH said:


> If 5b/254m has more or less the same electrical specs of 807 I expect these B36/B65 sound good also with them. When I'll order my Citadel with 12.6V heaters option I hope you will be nice enough to send me a box of tubes, since you bought all internet.
> 
> I am here still on the same ATS25, this time with 6N7. I can live with this my whole life but I know I'll get bored soon and change it.


Lol. I had a bid on 5 untreated b36 tubes. They were the coveted metal base models. I bid up to 200GBP but that was as much as I was willing to risk. Lost the bid but I’m not too broken up about it really. Odds are that there were some duds. As for buying the b36 internet I will have 3 pairs of the Fivre and one pair of Hammersmith made (I think). One of those is NOS, the other is used. Also have a lonely metal base b36 which tested at 60% or so. 

If you own b65 tubes, you can turn those into a lot of other tubes lol. B65 prices have gone crazy.


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## OctavianH

I play in another league than you, my focus are tubes around 5-10 EUR which sound better than the expensive ones. I wait for a quad of Tesla EL81 for which I paid around 20 EUR.


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## Isaacc7

OctavianH said:


> I play in another league than you, my focus are tubes around 5-10 EUR which sound better than the expensive ones. I wait for a quad of Tesla EL81 for which I paid around 20 EUR.


And I consider myself a cheapskate! Lol. $100 a tube is about my limit but obviously I can’t buy many at those prices. I think those b36 I just bought were 56GBP each. The tough ones are the single triodes. Since I need 4 at a time they add up quickly!


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## OctavianH

RCA 807 + Brimar 6N7. I guess these are the brands I respect the most. RCA are excellent in many forms, 807, 6N7, 6SL7 are great. The bass is spectacular in this combination. RCA is full bodied and dense, sounds "heavy" while Brimar cleans and sweetens it a bit. Match made in heaven, I had no such pleasure in listening with several hundreds EUR combos. And I am not joking, this is why I am bored about expensive tubes.





It might be the amp, it might be the D8000 Pro or hell knows, but I am sold to these 807 / 6SL7 / 6N7.


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## Isaacc7

OctavianH said:


> RCA 807 + Brimar 6N7. I guess these are the brands I respect the most. RCA are excellent in many forms, 807, 6N7, 6SL7 are great. The bass is spectacular in this combination. RCA is full bodied and dense, sounds "heavy" while Brimar cleans and sweetens it a bit. Match made in heaven, I had no such pleasure in listening with several hundreds EUR combos. And I am not joking, this is why I am bored about expensive tubes.
> 
> 
> 
> It might be the amp, it might be the D8000 Pro or hell knows, but I am sold to these 807 / 6SL7 / 6N7.


The 807 is my go to output tube. Amazing performance for the money. Even the most expensive 807 i’ve seen isn’t all that much. 

The input tubes are where I get a bit more picky. I have had very little success with RCA tubes. Which is a shame because they are so reasonably priced and available. 

Favorite bang for the buck twin triode has to be the 14n7 clear glass. The 7n7 tall bottle clear glass is right behind it. No reason to spend big bucks to get good sound. Metal single triodes are still a steal but you have to factor in the price of adapters.


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## OctavianH (Yesterday at 3:09 PM)

Isaacc7 said:


> The input tubes are where I get a bit more picky. I have had very little success with RCA tubes. Which is a shame because they are so reasonably priced and available.


I like the RCA 6SL7 clear glass. Nice tube. Also the RCA 6N7 is very nice in my book. RCA pairs well for me with GEC outputs. RCA outputs pair well with Brimar or GEC for a little bit of sweetness. But of course each one with his/hers own recipe. I had in the past VT-231 grey glass from RCA and they were nice, sold them. Too expensive to keep without a plan to use them. I will never return to 6SN7... I'll keep a few I have and like and that's it.

I think the future belongs to 6V6 and 6SL7. I feel that these 6SL7 sound incredible on SET amps and sooner or later these will take place of 6SN7 in price. More and more low impedance headphones are coming out and the high impedance ones start to disappear. Cayin already released a nice HA-3A and everyone is hyped about it. I have a feeling next steps are some 6SL7 based SET amps with 6V6 outputs (KT88/77/66/6L6 and so on). I heard what 6SL7 can do and... I bought a stash of them to be sure.  I am fully convinced these will become soon unobtainable.

Later edit:
I had an incredible pleasure to read this in the morning. Excellent, some fellow head-fiers are much above professional reviewers.


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## Isaacc7

OctavianH said:


> I like the RCA 6SL7 clear glass. Nice tube. Also the RCA 6N7 is very nice in my book. RCA pairs well for me with GEC outputs. RCA outputs pair well with Brimar or GEC for a little bit of sweetness. But of course each one with his/hers own recipe. I had in the past VT-231 grey glass from RCA and they were nice, sold them. Too expensive to keep without a plan to use them. I will never return to 6SN7... I'll keep a few I have and like and that's it.
> 
> I think the future belongs to 6V6 and 6SL7. I feel that these 6SL7 sound incredible on SET amps and sooner or later these will take place of 6SN7 in price. More and more low impedance headphones are coming out and the high impedance ones start to disappear. Cayin already released a nice HA-3A and everyone is hyped about it. I have a feeling next steps are some 6SL7 based SET amps with 6V6 outputs (KT88/77/66/6L6 and so on). I heard what 6SL7 can do and... I bought a stash of them to be sure.  I am fully convinced these will become soon unobtainable.
> 
> ...


Be careful about dismissing an entire tube type. I’ve found that is very amp specific. *sl7 tubes very well in my Odyssey but not so well on my SE amp.


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## OctavianH

Isaacc7 said:


> Be careful about dismissing an entire tube type. I’ve found that is very amp specific. *sl7 tubes very well in my Odyssey but not so well on my SE amp.


I am not dismissing, I've just moved my focus to others. I remember before Eternity I had an Elise and on that one I was listening mostly to KT66 with 6V6 on input and the same are doing several guys on Euforia now. Since I do not plan to move from UltraSonic brand too soon I guess I am fine with my assessments.


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## OctavianH

David and Goliath, a good way to start your morning.


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## OctavianH

RCA 807 plays a little bit with the sub-bass of D8000 Pro. This is not a bassy headphone, but it has a full bodied sound and can be very detailed when needed. I love it. But RCA closes somehow the soundstage with that tight bass. So I needed something to widen a litte bit the things and here the GEC 6C4 KB/Z come into place. I like a lot these tiny creatures, they do for 12AU7 what 6J5 does for 6SN7. They add that air and sweetness which I was missing. This is tube rolling, a compromise.


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