# Elekit TU-8200 DX Headphone/Speaker Amp Review



## Effusion (Feb 1, 2021)

*Elekit TU-8200DX Impressions/Review*​ 



 Background: The TU-8200DX is a speaker and headphone amplifier kit, designed by Mr. Fujita of Elekit Japan as an upgraded design, with new features, to their highly praised and regarded TU-879S kit.  For North American enthusiasts, the kit can be purchased directly from Victor Kung of VKMusic in Canada, which includes English instructions.  The kit currently runs $725 US for the "DX" version from Victor, which includes 4 Amtrans AMCO 104 PET capacitors as well as 4 Nichikon conductive polymer aluminum electrolytic capacitors.  There's also an option through VKMusic to add an additional Elekit PS-3249 USB DAC to the unit as well.

I had the pleasure of meeting Mr. Kung of VKMusic at the 2013 RMAF show and I'm really glad I was able to talk with him about his passion for DIY and the various kits as well as fully assembled products offered by him to the North America market and sourced from Elekit in Japan.  I have been interested in a few of Elekit's offerings in both the distant and more recent past, including the highly regarded TU-882, which uses one of my favorite signal miniature vacuum tubes, the 2c51/396a/5670.  Unfortunately I've never been able to audition the TU-882, so I can't comment on its sonics, but if you are interested here is a great review done a few years back by Skylab.

When I approached Victor's table, off to the side of the main lobby of RMAF, I was originally interested in another new and interesting offering from Elekit, the fully assembled TU-HP01 Portable Tube Headphone Amplifier, which I had only learned about in the days prior to the show.  I was also hoping that he might have also brought along a TU-882 with him, but unfortunately he hadn't.  Although the portable TU-HP01 sounded great with his pair of AKG's, it's output is rated too low for the pair of HD650's I took along with me to the show, so I found myself looking around the table at the other offerings.

At the time I wasn't very familiar with the prior Elekit flagship, the TU-879S, but it's newer/improved sibling struck my interest right away.  For the last 4 years I've found myself spending the majority of my time at RMAF sitting at the Woo Audio table, drooling over their excellent WA22 amplifier and the way it truly represented the best out of my HD650's.  That all changed this year, thanks to Victor for making the trek down from Canada to spend a weekend in a hotel full of audio nuts, cradled up against the beautiful Rocky Mountains.

After speaking with Victor for a bit, I grabbed a chair, took out my custom Headphile HD650 headphones and plugged in.  Wow!! Really??  Right away there was this indescribable new sense of presence and life in my headphones that I had never really heard before.  I remember thinking right away, "...wait a minute, something strange is going on here!?"  So, without hesitation, I popped out my trusty RMAF audition CD, containing various tracks I've used as reference throughout the years, and placed it onto Victor's 47 Treasure CD Player/DAC, which is a really cool and great sounding kit BTW.  Cycling through the 16 tracks on my disc, I was astonished and outright amazed by the sound-stage, detail, presence, and tube bloom goodness I was hearing out of this amplifier.  The resonance in the lower mids and upper bass was the best I could ever remember hearing out of these cans at that time, with the sear impact and deepness of the bass playing through the HD650's being previously unknown to me.  Acoustical instruments had great air and resonance.  Vocals, especially female, were just breathtaking.  Also, although generally disregarded with tube amplifier designs, the highs I was hearing were ever so present, being both well extended and with just the right amount of sparkle, kind-of similar to finding the right tube combination that seems to leave the highs completely intact while others do not.

As you can imagine from my initial experience above, I ended up spending quite a bit of time at Victor's table that Saturday, only taking a few minutes at the end of the show to quickly run upstairs and try to get some idea of a comparison to my beloved RMAF staple, the Woo Audio WA22.

After returning from the show in October, I spent the next few months contemplating the Elekit TU-8200.  Could this Japanese kit really be as good as the WA22, at a fraction of the price and with more features?  Could it really be a "giant killer" in the world of desktop audio?  Or, was it more of a factor of the crazy/cool 47 Treasure DAC, or perhaps even the tubes (but unlikely because they were stock).  Was it a trick my mind was playing on me, since I've really wanted the WA22 for so long and this little guy is more than half the price.  Well, I came to the decision that I needed to know the answer to all of this and hopefully much more, so as soon as the TU-8200DX became available through VKMusic in late January, I ordered a unit from Victor.

The Arrival: The amplifier was shipped, doubled boxed and with a ton of packaging to ensure safe delivery, and arrived from Canada
in about 5 business days (one was a holiday).  I was surprised by the weight of the unit, it's not as light as it looked on Victor's table, so shipping through Canada Air is obviously not the cheapest, but much much less than it would be from Japan.  The kit includes all pieces required for assembly, including the additional "DX" capacitors, English instructions, and 4 brand new tubes (2 Electro-Harmonix 6L6GC's and 2 Chinese 12au7's), plus plenty of packaging to keep the unit safe.














Specifications: The Elekit TU-8200 amplifier includes some really cool features outlined below:


Active Automatic Bias Adjustment Function
That's right, no need to manually adjust the bias of the amp every time you tube roll, just plug 'n play!



3 Amplifier Modes
Ultra-linear, Triode, and Pentode modes can be selected easily by simply moving a jumper into different connection paths on the PCB



World-Wide Power Transformer
4 different voltage settings, switchable by a plug near the power transformer - 100V, 115V, 200V, and 230V



Speaker Impedance Switch
Switch easily between 4-6.3 ohm and 8-16 ohm speaker output modes



2 RCA inputs and one 3.5mm stereo mini input


Optional USB DAC upgrade


Loaded at 8 ohms and with a standard 6L6GC power tube, the TU-8200 can deliver 4 watts per channel in Triode mode, 8 watts in Ultra-linear, and 8.2 watts in Pentode.  Banana plugs can also be used.


With the help of the automatic bias adjustment feature, you can roll quite a few popular audiophile vacuum tubes in this amp, including the following:
Power Tubes:
6L6GC, KT88, 6550C, 6CA7, EL34, 5881, KT66, 807 (with adapter), KT77, KT90/KT99 as well as all of the usual direct equivalents of the 6L6GC.  However, 6L6's and its variants are not recommended, only the GC.

Input/Signal Tubes:
12AU7, ECC82, CV4003, 13D5 as well as the usual direct equivalents/replacements of the all of these types


Setup:

*Source*: FLAC files ripped securely by myself using EAC and played through Foobar2000 using WASAPI in "push" mode
*DAC*: Larry Moore's Ultra-Fi DAC 41 with Twin Reg upgrade installed, built in the spring of 2012 and feed with an Ultra-Fi Digital Conduit USB cable
*AMPs*: TU-8200DX (professionally assembled using high grade German Silver Solder) vs. a Darkvoice 336se
*Headphones*: Sennhieser HD650 - Headphile modded with Ebony/Bloodwood woodies and a Headphile Black Gold cable
*Speakers*: 2 Energy RC-10 Rosnut Monitors
*Cables*: Blue Jeans RCA cable and two Iron Lung Jellyfish power cables
 Impressions: I've spent about 5 months now with the Elekit TU-8200, which is fully burned-in, with at least ~225-250 hours logged so far and ~30 hours when I started to listen critically.  I've also rolled quite a few different types/brands of tubes with this amplifier already, which have really given me a true representation of all of its many abilities.  With tubes momentarily disregarded, I'm finding it hard to find many flaws with the sound coming out of this amp, at least to my ears and my preferences.  It's a really great sounding DIY amplifier!

The whole audible range is there, with some of the best done lows and highs I've ever heard out of the HD650's.  Now, granted I'm coming from exclusively using a Darkvoice 336se for the past 5-6 years, which is a great inexpensive amplifier that seems like it was just made for the HD650, but it does have several shortcomings, especially when compared to the TU-8200DX.  I've also auditioned many great sounding amplifiers including the very excellent Zana Deux.  With the Darkvoice 366se, I have rolled over 100 different types of tubes, ranging over many years and countries of origin, which has given me a solid foundation of what the Darkvoice is really capable of.  However, tube rolling is much more responsive with the TU-8200, especially prior to burn-in.  I find that the differences in tubes are no longer similar to cable changes, as subtle variations in tone and acoustics, but much more impactful, making my HD650s seem almost like entirely different headphones many times.  Also, overall the Darkvoice is also just that, a little dark across the spectrum, while the TU-8200DX is more forward and nicely extended, which can really help even-out the "veil" of the Sennheiser 600/650 line.

The TU-8200DX is also much more detailed than the Darkvoice 336se and I'm now more confident that I'm hearing many of the nuances and details that the DAC 41 is getting out of the music.  Instruments and voices just have more body/depth to them than before.  The TU-8200DX also has much better separation and imaging than the Darkvoice 336se, probably mainly due to the separated channels and better components/design.  The sound-stage is also much better with TU-8200DX, with some tracks I use exclusively to test this being absolutely jaw-dropping as far as width and depth; certain tubes give a truly 3D holographic image on many recordings.  Now, I'm not saying that the Darkvoice 336se is a terrible amplifier, not in the least, at least for the price.  I've spent a ton of time with this amplifier and it is truly great mid-fi, but it isn't nearly as refined and resounding as the TU-8200DX, but of coarse it's less than half the price and is already built.

Highs: The highs are amazingly represented by the TU-8200DX, being not only extended, but also not nearly as "hidden" as I've experienced in other tube based designs.  They are still a little rolled-off, so extreme sparkle, that can not only sometimes be a bit bright, but also a little harsh to some, including me, is replaced nicely with a general smoothness to anything peaky.  Violins and strings have great tone and body and cymbals have the right amount of crash and air, without being sounding too hard.  Compared with the Darkvoice, the TU-8200DX has a nice open treble with much more definition.

As far as sibilance, I've been unable so far to find even the slightest hint of sibilance out of the TU-8200.  There are few songs I use exclusively for this purpose, one in-particular is Alela Diane's "White as Diamonds", a folk/country artist that can be very sibilant at times.  Only a few tubes in the Darkvoice 336se could really smooth it out, but with every tube I've tried so far with the TU-8200DX, I can't seem to get any sibilance at all, her voice inflections are just perfectly smoothed out every time.  Very cool.

As a side note, I can be very sensitive to very bright highs, so I tend to try to avoid equipment known to be overly bright in the highs; the DAC 41 is for one, a NOS DAC and can be very laid back at times compared to OS alternatives.  However, the highs out of the TU-8200DX have been just perfect for me, brighter than I am use to, but in a good, not bad way at all.  I finally feel like I can enjoy high tones and even a little more brightness than I'm used to, all awhile not feeling fatigued or experiencing any pain over time; they are very smooth and refined in this regard, if not a little laid back with most tubes.

If you have a brighter source and/or headphones than mine and like sparkle in the higher frequencies, I'm sure the TU-8200DX will satisfy your needs, at least for a tube design, and if it doesn't right away, then merely switching out the signal tubes to Telefunkin Ribbed Plate NOS 12au7s, should give you more than enough dazzling highs.  The Tesla NOS Blue Glass EL34s also offer some really great sparkle, but at the cost of a little less weight in the lower end.

Mids: As far as the frequency range of audible sound is concerned, I wouldn't hesitate to call myself a mid-range junkie.  To me the mid-range is the most important part of the spectrum and if you can't get it right, the rest of the sound falls apart.  My preference for the mid-range is also why I tend to prefer tube based gear as opposed to solid state; I just can't get enough of the natural tone and resonance that a great tube bloom can give in the mids and upper bass.  So the question is, do I enjoy the mid-range of the TU-8200DX?  Well, lets just say that I wouldn't have gone to all this trouble writing about this amplifier if I hadn't... it is good, really good.

I find the TU-8200DX to have a very nice open and detailed mid-range, without sounding too dark.  It is in fact much more open and detailed than the Darkvoice 336se all awhile being more forward in it's presentation, which is actually a very good thing for the HD650's.  If I had to classify it with just listening to it with the HD650's, I would say that it is more on the darker side of neutral in the mids, however the 650's are a little dark so this may be even closer to neutral than my impressions, that is with a more neutral pair of cans.  Voices sound very natural and inviting, especially female vocals, which with the right combo of vacuum tubes can sound so silky-smooth and seductive that many times I was just blown away.  In fact, what initially blew me away at RMAF was several female vocal tracks that I use to judge the upper mid-range as well as sound stage.  If anyone is familiar with Mariee Sioux, Alela Diane, or Lou Rhodes, I don't think I've heard a better representation of their voice's sheer beauty than with the TU-8200DX.  I'm sure you'll enjoy the sound of the TU-8200DX with your favorite female vocalists.

Of course, using different signal tubes you can really tweak the sound and tone of the mid-range of the TU-8200DX.  I've really enjoyed Brimar variants with this amplifier and found that they give just about the right amount of "presence" to the mid-range.  Mullards are also very good, a little laid back and probably the smoothest sound in the mid-range, but at the expense of micro-detail.  The Telefunkin smooth plates are also very nice, a little less silky, but with great detail and imaging.  A few pairs of Amperex have also impressed me in many different ways throughout the mids.

If you judge an amplifier by how well it does the mid-range, than I don't think the TU-8200DX will disappoint.  If you find it doesn't quite have the flavor that you crave, then a simple signal tube change can really make a difference to suit your cans or speakers.

Lows: I won't call myself a "bass-head", but then again many that do enjoy a good amount of bass sometimes won't call themselves this term either, but I like bass that has weight/punch and when required resonance.  However, I find almost nothing more unpleasant (even more than a congested mid-range) than either a very sloppy/uncontrolled/boomy low end or especially one that is virtually nonexistent.  I will tell you that at first I was a little worried about the bass with the TU-8200DX... however, I broke the golden rule and listened to the amp before it was fully burned in, while the bass was a little soft and hasn't opened up entirely.

Anyway, at first, without much burn-in, the bass was very soft and without impact and appeared so no matter which power tubes I tried.  After at least 10-15 hours of burn-in and swapping the stock EH 6L6GC tubes out for NOS GE 6L6GC, the bass all of a sudden came alive with great force and power.  Now, I've found that the GE 6L6GC tend to be very bass heavy tubes, but after at least 60 hours of burn-in most of the power tubes I've tried have had a least a very decent amount of presence.  Currently, slight changes can be heard between overall weight, depth, and resonance with all, but the KT66's and KT88's give a very nice forward and powerful representation.  I've found that with GE 6L6GC, KT88, 6550, and KT66 tubes the bass really shines out of this amp, at times the best I've ever heard out of the HD650's.  On a few tracks that I've become accustomed to, the bass is more subsonic than I have ever heard out of the HD650's, at times even seeming to tickle the hairs within my ear canal, which is not very easy to do.

Even though with the right tubes you can really get your bass fix, it has never at any time, with any tube combination been very sloppy, uncontrolled, or boomy... just always a nice variation in weight, punch, and depth that can suit many types of music.  I have found that EL34's tend to be a little more shy when it comes to the bottom end than KT88s or KT66s, however they have a beautiful mid-range and probably the best sound stage out the variants I've tried thus far.  The Mullard EL34s do have a very strong bass presence compared to other manufactures while the SED Winged "C"  or Phillips/Amperex EL34s have very nice sound stage as well as a very open mid-range.  So, once again, I've learned my lesson to just simply wait until the amp has fully burned-in.

If you tend to find yourself opting for less bass in your listening preferences you can try a pair of EL34s for some extra mid-range detail.  If you like rock than maybe a pair of GE/RCA 6L6GC's will add some nice punch/drive to a more laid-back headphone/speaker.  If you can afford them, NOS KT88s and KT66s will give you almost all that you may desire, with a nice forward presentation.  Only a few 12au7s so far have given me a boast to the bass over the rest, with Brimar 13D5s, CBS 5814W black plate, Amperex ECC82, and RCA Clear Tops giving the most.

Speakers: Unfortunately, due to close proximity to my neighbor's bedroom and the fact that they have have a little one, as well as me probably being a little too polite, I haven't been using my Energy RC-10 monitors as much as I used to.  Thus, I haven't been able to properly test the speaker out of the TU-8200DX, at least as much as I would have liked to for this review.  However, I can say that they drive the Energys with more than enough power for normal listening levels in the 4 watt per channel Triode mode.  Now, the Energy RC-10s have about a 91 DB sensitivity rating and with the port plugs out probably a little bit more, so they are fairly efficient.  If you plan to drive monitors with at least a 90 DB sensitivity rating than I don't think you'll have any problems using the TU-8200DX at normal levels and if you want to be safe, changing the jumpers to Ultra-Linear mode should give you the headroom you desire.  I would probably not recommend running any large full range or monitors with less than 90 DB sensitivity.

Conclusion: So, does the Elekit TU-8200DX answer the question I posed to myself after RMAF?  Is it the giant killer I've been looking for?  Is it as good as the Woo Audio WA22?

Well, it has given my library a new fresh breath of air and has invigorated my enjoyment of the music in my life.  For me it does just about everything right and all in the natural tube bloomy way I've come to enjoy.  It has given me a new appreciation for high frequencies, without turning me away with bright or peaky treble.  It has really opened the mid-range and has allowed me to hear more of the music contained within, all awhile providing a nice smooth and silky texture that is very engaging at times.  The bass has me hearing things I've never heard before with my HD650's, sub-sonics that tickle my ears and controlled punch that is fast and also very enjoyable.

But, is it as good or even better than the Woo Audio WA22?

I wish I could honestly answer this question, but even though I really have to say that I can't, at least not with absolute certainty and for sure, the Elekit TU-8200DX has actually made me so content that I can honestly say that I no longer really care...   If I previously or currently owned the WA22, than I think I could make an educated opinion for one way or the other.  However, I've only been blessed with hearing the WA22 at RMAF briefly each year and not for very long as it is a popular attraction.  If I was forced to place a bet, I would put my money on that the TU-8200DX is probably right about on par with the WA22 in unbalanced mode, to most listeners and with the majority of music.  I would say that while I enjoy the power tube choices on the TU-8200DX more, the 6SN7 tube of the WA22 is just a very fun tube in general.

The real question I think one must ask themselves is what features are important to them and for what price.  The WA22 is almost 3 times the cost of the TU-8200DX, although you do have to assemble the Elekit.  If running balanced headphones is a requirement from a balanced source, than the WA22 would probably have to be the choice.  However if you would like to use the speaker outs of the TU-8200DX and the ohm and output mode adjustments interest you, than the Elekit is a better value.

Then there comes the tube rolling options.  With the automatic bias feature of the TU-8200DX, the tube-rolling possibilities are almost endless and with new production tubes in these variants, if NOS isn't your bag or too expensive, other options are available.  The WA22 also takes a rectifier tube and both the tubes that the Darkvoice takes, the 6AS7G and 6SN7.  There aren't many options for the 6AS7G and I don't believe many in new production, but they are plentiful and mostly pretty cheap.  I prefer the openness and sound stage of the 6080 variant, but it's even more scarce for the good ones; Brimar solid cast-iron plate 6080's are nice and clear up top and very open in the mids.  On the other hand, the 6SN7 were one of the most produced tubes at one time, but prices have risen in the last few years and matched pairs can now cost a little more (many are asking prices for run of the mill basic constructions that are too high).  However, in general they are less expensive than the majority of the tubes you're going to want to try in the TU-8200DX.  As far as NOS, 6L6GC's are a little cheaper, so are 5881's and 807's, but the majority of EL34's, and the KT series are expensive.  Cheap 12au7's can be found, but nicer sounding and more rare options can go for a lot as well.

In addition, the ability to switch output modes in the TU-8200DX and even changing something as trivial as the LED color, it's not very hard to argue which has the better tweak-ability out of the two.  Not even to mention the extra space on the Elekit's PCB board to add bigger and better caps if you enjoy modding.

If you're interested or experienced in DIY or have basic experience building/soldering kits, I don't think you'll be disappointed in the TU-8200DX for the price.  Then again, if you aren't a DIY'er or just not completely confident in your abilities than you can always try to find someone that will build the kit for you.  This is what I did and I couldn't be happier with the result.  I think I'll be holding on to this amplifier for a very long time...
Side Note: Unfortunately, about halfway through this review I managed to blow the left channel Q3 FET on the TU-8200DX... it was a real big bummer as I was just about to finish this review.

As a warning of caution, please don't try the 807 European variant labeled as QV05-25.  I purchased a pair of NOS Mullards and the FET blew after about 5 minutes.  I believe this variant is out of spec for this amp, with working adapters, as the plate voltage I believe is actually a lot higher than an RCA 807 or common variant.  At first I thought the left tube had blown; all of sudden the left channel went dead and the LED turned purple, however later I had this pair tested and they are as NOS as you could really get... shame.

After the channel went out, I contacted Victor immediately and within less than 1 minute, that's right, less than 60 seconds later, I had a reply from him.  Within about an hour I had another reply from Victor who had contacted the designer with my initial question and later that night I also received a phone call.

All I can really say is that I'm definitely not use to this kind of customer support and I can't say enough about how great a guy Victor truly is.  Ever since I met him last year at RMAF he has taken so much time and care regarding my amplifier as well as all my questions.  DIY is really his passion and he has devoted much of his current free time to these kits as well as the customers who purchase them.  I truly believe he is doing this for the love of DIY and of music; even though he has a non-audio related full-time job, he seems to transcend these passions onto all of those who he meets.

In the end, the FET was replaced and organic caps were also installed at the same time.  These caps have given the sound a little more openness, detail, and richness while keeping the natural tone as well as presence still intact; a very nice addition and recommended.

*New Version: * The new version of the TU-8200 is the TU-8200R, which includes the following upgraded features:

Better components
ALPS R27 volume pot
LOW ESR conductive polymer hybrid aluminum cathode Bypass capacitor
Headphone impedance can be selected by changing the jumper location
The protective circuit has been improved to avoid malfunction due to tube rolling
*Videos showing assembly:*
Below is part 1, out of 4 parts, and there is also an unboxing and final assembly video:

How To: Assemble the Elekit TU8200R Amplifier Kit


*Internal thread links to expanded info on tubes for the TU-8200:*
https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12726831

https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12728793


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## benjaminhuypham

Great review Mr. "Tube collector" Effusion,  I was the one who witnessed and auditioned the Kit with my Q701 at RMAF last year and Oh man, it was astonishingly transparent and new natural sounding amp that I have ever heard with the Q701. The feelings were simply incredible and I shouted inside my head : "Got to ask Victor about the price immediately 
	

	
	
		
		

		
		
	


	




". I was only wowed by various brilliant combos, such as 009/Blue Hawaii Se, LCD2/Violectric v200, and HD650/Crack, and Q701 and Elekit TU-8200DX is one of those. Maybe I'm probably gonna wrap one at RMAF this year.


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## Xenophon

Thank you very much for this extremely detailed review!
  
 It was very interesting as I've been looking at the Elekit amp myself and currently use a DV 337 as my main tube amplifier (very happy with it, btw but of course I don't know how it compares to your 336 or to the Elekit).  To me the 337 sounds quite neutral for a tube amp, I dislike the typical so-called 'lush' tube amplifiers which to me are only indicative of sloppy design and badly driven tubes.
  
 I'm currently working on a DIY tube project but will definitely keep this in mind, especially for the versatility it brings.  I listen mainly to classical instrumental music and like a clear sound and good midrange.


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## Effusion

The 337 is a very good amplifier and regarded as more refined than the 336se, but they do use different tubes and the 6sn7 makes the 336se very versatile.  Unfortunately, I haven't had the pleasure of hearing a 337, always wanted to, just no access.  Although, I would say that where the bloom in the 336se was sometimes a little "slushy", it is definitely tighter, with better layering with the Elekit; many 12au7 tubes such as the Telefunkin, GE, Westinghouse, RCA,  and Raytheon (esp. the 7730 gold pin variant for clarity) seem to provide more of a balance.
  
 If you like the sonics that the tubes bring, but without being overly lush,  I've found that newer production, especially higher end, sound really good, with much more of a subtle bloom; almost solid-state sounding when compared to most NOS types, with generally great highs.  There are a ton of tubes you can roll with the Elekit, but even with all these options prices can be expensive, even for good new production pairs.
  
 I've heard great things about Psvane tubes as of late, but haven't tried them yet.
  
 Good luck on the build!


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## Effusion

benjaminhuypham said:


> Maybe I'm probably gonna wrap one at RMAF this year.


 
  
 Victor did mention to me that he plans to attend the 2014 RMAF show and I'm sure he'll bring a TU-8200DX to audition again.
  
 Same sediments exactly, great sounding amplifier, even though at the show it had stock tubes!!


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## benjaminhuypham

Yup! His table last year was very close to the entrance door. I didn't like the portable amp of his with the K701, and I found they were a bit harsh and sibilant. However, when it came to the tube amp, they became totally different beast. My AKG q701 pair extremely well with the amp and HD650 does too, but I did not have enough time to listen for long. I will be getting the HD650 soon and thinking about either building the Crack or purchasing the kit. I'll decide after RMAF this year. 

Thumb up for your Amp, great choice. Met you last year at Denver meet and your tube collection is simply magnificent. 

Ben


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## Effusion

Hi Ben,
  
 Thanks!
  
 I definitely enjoy the variety.... already have quite a few for the Elekit as well.  
	

	
	
		
		

		
		
	


	



  
 Hopefully you were able to audition JmanOfIsrael's Crack during that meet.  I'm not sure if it was fully burned-in, since he had just built it, but it sounded great!  Although, in comparison to the 336se at that time and with a few of my favorite 6AS7G/5998s the Crack came across as very polite, if not even a little too shy for my general tastes, albeit with a very sensual and seductive presentation of its own.  The speed and impact of the 336se was just much better, but then again this Crack didn't have the Speedball upgrade and may have not fully come into its own at the time I auditioned.
  
 With my brief introduction to the Bottlehead, I would have to conclude that since the speed/impact of the TU-8200DX was on par if not generally better than my 336se, that it would also be both faster and have more weight than the Crack in general.  Of course, the laid-back, seductive, and rich sound of the Crack can be a very big positive at times, just really depends on the type of music you enjoy most.  I can see the Crack being perfect for Jazz, Blues, and Classic Rock, but maybe a little too slow/soft for anything produced or overly complex.
  
 Also, I would speculate that the Crack is an easier build and maybe better suited for first-time builders, as it is point to point wiring and the Elekit does have a PCB board.  Even though I didn't build the Elekit myself, Victor did assure me that not only is it a fairly easy build for beginners with great instructions, that it is also one of the most fun kits he has ever built and I've gotten the impression that Victor has built quite a few kits over the years.  So, if you enjoy DIY and don't mind the extra hours and precision needed to properly complete the PCB, in addition to the higher price tag, and at times you listen to music that requires a little more speed as well as impact, than I think you would enjoy the Elekit.  Plus with the options for tubes, speakers, and upgraded components, the Elekit is more versatile.
  
 Maybe Bottlehead will be at RMAF this year and you'll have the chance to compare!


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## vkung

I asked Mr. Fujita our chief designer  the  topography for headphone section found in TU-8200
  
Here is the answer from him.
For most  integrated amps with vacuum tubes, there are not so many of them with headphone terminal in the market. Even if they have, they usually adopt an exclusive circuit for the headphone, which in most cases are solid state. These headphone circuits cannot realize pure tube sound. For the TU-8200, there is no exclusive circuit for headphone terminal. Mr. Fujita our chief designer simply connected the headphone terminal to the tube amp itself, adding only three resistors on the signal path.
 
This is not as simple as it sounds. Unlike solid state amp, impedance matching is of critical importance for tube amps. Mr. Fujita did not just lower the voltage to maintain drivability of the headphone but also had to carefully consider the impedance of the headphone to be connected. He finally optimized the impedance value with three resistors to deliver pure tube sound.”


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## Xenophon

It's not terribly complicated either, you need to ensure that the headphone load that's reflected back via the output transformer matches the 'expected' speaker load which will mostly be 8 Ohm.  Check out this link to calculate the resistor values specifically for the impedance of your headphones:  http://robrobinette.com/HeadphoneResistorNetworkCalculator.htm
  
 There's no such thing as "He finally optimized the impedance value with three resistors to deliver pure tube sound.” that can be factory set and is optimal for all headphones.
  
 But I do very much admire the versatility of the build, that's the real challenge:  finding a good compromise.  Building a tube amp that just has to sound great with one type of tube and one set of headphones that you know the specs of is not extremely hard.


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## vkung

Calculation is one thing.   According to Mr Fujita,  he was extremely careful in selecting the output transformer for TU-8200 to fit this purpose


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## vkung

TU-8200DX 6moons review
http://6moons.com/audioreviews2/elekit/1.html


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## Effusion

Very interesting review from David Kan on 6moons... if you're interested in how the TU-8200DX performs with speakers and in different output modes I recommend checking it out.  Thanks for the link Victor!
  
 I exclusively used the amplifier in Triode mode for my review and impressions, since this is the mode I'm most accustomed to, but I now think I'm going to have to try the Ultra-Linear mode as well.  
	

	
	
		
		

		
		
	


	



  
 It appears that David was also wowed by the headphone stage of TU-8200DX towards the end of his review, while using his pair of Sennheiser HD598s.  Below is a quote of his impressions:
  
 "With my modest headphone I could hear all the tube variants in their best light*. None of them sounded excessive now, not even the Mullard EL34 in ultralinear mode. What used to be fat and bloated on the Synergy F2 now was intoxicatingly sweet on the HD598. And with the Genalex KT88, the golden piano tone and pearly touch simply melt my heart. I did try a few headphone amps in the past. This was the first time my perception of headphones was changed forever.
  
 * High-impedance headphone vs low-impedance speaker load paints the picture. When not tasked to drive loads which push their limits, tubes will behave far more linear and sound it. Here higher impedance is clearly better. - Ed"
  
 I wish I knew more about the specifics of the headphone output, but comparing it the 336se, which is designed solely for headphones (or as a preamp), the TU-8200DX is much more responsive to tube changes than the Darkvoice generally was.  As I mentioned in my review, certain tube changes made my HD650s seem like completely different headphones at times; the sonic differences between tubes were no longer equivalent to the subtle differences you can get with cable changes for example, but now much more impactful with the Elekit.
  
 As far as what headphones might pair well with the TU-8200DX, it's hard for me to say from personal experience, since I've exclusively used the HD650s, but it appears that this amplifier may pair very well with an assortment of different drivers/loads.  The HD650s are 300 ohm, while David's HD598s are 50 ohm, and Ben's AKG Q701s are 62 ohm, all of which seem to pair very nicely with this amplifier.  Only time will tell as more and more headphones are tried with the TU-8200DX, but I'm thinking that it could pair quite nicely with the majority of high quality headphones.
  
 However Mr. Fujita designed the headphone output, I'm really glad he did it the way he did.  I agree that many times amplifiers that are built with speakers in mind, tend to overlook and under implement the headphone output, seeing it as just another "feature" to add interest for prospective customers.  I can say that the headphone output of the TU-8200DX is very good, and overall the many features of TU-8200DX don't seem to detract from the sound quality of the amplifier at all.  Not only are these features useful, they appear to have been designed and implemented ultimately with sound quality in mind and at the focus.  For example, I could see how some tube rollers may have preferred to be able to tweak or dial-in the bias while rolling tubes, as some like a higher or lower settings with certain tubes, but from what I've experienced the automatic bias feature works really well.  I've already rolled almost every type/variant of tube in this amp and at no time have I felt like a tube wasn't biased correctly or that the bias control was degrading the quality.  For me, not having to worry about re-biasing the amp and at the same time being able to roll so many different types of tubes makes this amplifier extremely fun to use.
  
 Without good design, extra features really don't mean much in the end.  The fact that the quality of sound I've been able to get out the TU-8200DX, with all the extra useful features it has, makes this a very cool design my opinon.


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## bixby

well done review James, now your going to have to haul it to my place for some listening


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## Spareribs

Looks nice. It evokes the look of the of 1959 Marantz 8B.


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## Xenophon

In the 6 Moons article they mention in the specs that  it should play well with headphones having an impedance of 8 Ohm (!) to 1kOhm....  If that's true and you can listen at 8 without hiss AND still get decent power and detail out of the higher impedance cans then it's a real feat. 
  
 Anyway, for the money it's almost a no brainer.  If shipping and import duties + our 21% VAT to Europe wouldn't cost an arm and a leg I'd get myself one right away for sure.
  
 As for the changes when rolling tubes it's true that with for instance my DV 337, rolling tubes doesn't result in dramatic differences if you stick with one tube type.  A 6AS7G will sound a bit different from a 6080 for instance (difference with tubes like the 7236 or 5998 is more pronounced) but you'd be hard pressed to hear the differences between 2 brands of 6080, which -imo- is indicative of good design and a well chosen operating point.  When you mention pronounced differences when rolling, do you mean between brands of the same tube type or between 2 different types (eg between a 6L6GC and KT88)?  The latter would be logical as I assume the amp delivers a fixed B+ voltage that has to work with tubes having some wide variety in specs, you'd get radically different proportions of 2nd harmonics for instance.
  
 Ultralinear operation is nice with some types of music, I've tried it on a couple of builds and am forever fiddling between it and no-feedback triode operation, depends on the music and my mood..and I only listen to classical, go figure.
  
 Damn shipping cost and taxes!


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## twizzleraddict

Great review.
  
 I heard this at a local Vancouver meet and was amazed by the musicality of it. First listen, the music sounded extremely warm and inviting, drawing you in. Victor was playing CDs with this 47 Treasure CDP through the amp and driving a pair of HD650s. I'd be pretty happy with this combo and not want for more.


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## Effusion

If the TU-8200DX really does pair well with headphones of lower ohms, it would be very cool.  I do plan on obtaining at least 1 new headphone in the next 6 months, but probably either a medium or high ohm model, so we'll see.  As far as something like an IEM, which I personally would never use with this amp on purpose, I'm not too sure... might be some hiss; it would be quite the feat if it did though!
  
 It's nice having someone like Victor so close, as shipping and import is much cheaper.  I wish it was a little more feasible for you, as it is a very nice amp.
  
 As far as tube rolling differences, I actually mean both differences, between variants and brands that are both more impactful; however it comes in varying degrees of impact, so it would help if I clarify.
  
 An analogy of these differences I could try to use, would be similar between different types of cable changes, where some can have more of an impact than others seem to.  I would say that the differences in brands, but same make of tube, are generally much more subtle than differences between different labeled designs.  Such as the differences one might find between 2 really good RCA cables of similar material.  While the differences between actual variants is more discernible and I find is easier to detect.  More of like going from the stock power cord to a nice high end power cord of good quality materials.  I would say that I've found the effects are generally twice to close to three times as impactful between variants than between most brands of the same.  Of course, everyone's mileage will vary by system and I've also not not always found this to be the case; the automatic bias feature of the TU-8200DX does make auditioning these many variants easier.  However, the sound quality has always been very good with the tubes that I've tried so far, just interesting alterations between them, that I believe is due to the greater resolution of the amplifier when compared to the 336se.
  
 There are a ton of tube-rolling threads out there over sonic differences between brands, but I've often found that it is best to let my own ears decide sometimes and will try any manufacture at least once.  I do believe that everything from the materials used, to the fitting of the factory, and especially design can lead to differences in characteristics; how small vs. big these differences are is dependent on many things.  There are a ton of ways manufactures designed their tubes in the day, even within the same family/brand, usually at least distinguishable by the years of production.  Some specific factories, such as Mullard's Blackburn, tend to give more resolution/detail than Mullards made elsewhere, as their factory in India.  Everything from plate structures to getter shape/location all seem to have an influence on the signal, I guess it makes sense, since the tube is in the path of the music.  If this wasn't the case I've found, my wallet would be a lot happier!   There would also be no need to switch out the stock tubes, or run a Bendix 6080WB or GEC 6080, rather than a GE 5 Star 6080 or run of the mill RCA, which in my opinion can sound very thin often.
  
 As far as the impact between rolling the 336se to the TU-8200DX, I believe what I'm hearing is partially due to the better separation between the channels in the TU-8200DX.  That the added silence, detail, and resolution from the Elekit has made the sonic differences more distinguishable than before, at least for me.  At times, it has made me wonder if I was ever truly getting all the differences between the different brands/designs of 6SN7s in my 336se because of some congestion/bloat.  I never felt much congestion nor bloat with all of the tubes I've tried so far in the Elekit, unlike a few with 336se.  Also, during the burn-in period these differences were much more pronounced and since have smoothed out quite a bit; blending in better and are now a little harder to pick out.  I use a selection of 15 to 30 seconds clips that focus on some of the sonic aspects the tubes seem to impart on the sound; some show me lower mid-range resonance levels, while others sound stage/imaging, and even a few I use to test high frequency, such as the crispness of a cymbal crash and the layers of resonance that follow; I also find that even voices are very good for testing.  Over time, consistent use of these test tracks has given me a better baseline to judge between various brands, which isn't always an easy thing to do.
  
 I have spent some time with 6AS7G/6080/5998, as it is the power tube in the 336se as well, but unfortunately there isn't huge copious amounts of different types of this tube to roll out there; there are still a few though.  The 6AS7Gs are almost all RCAs, with a few being made by tungsol/chatham for military use.  There is a small difference in the mids/bass between the black and gray plates, with the gray plates being a little softer around the edges with better mid range and sound stage; the black plates are older with silver lettering, while the more recent production gray plates have orange lettering.  I find that the bass is somewhat lacking on the gray plate RCA, with the black having better weight.  The 5998 is almost exclusively Tung-sol with re-brands by Chatham, which I find is more in line with the sound of the 6AS7G than the 6080, but with deeper bass, extended highs and more weight to the sound.  It is hard with the 5998s, as they also give a bump to the overall gain, so everything is more pronounced unless adjusted.  The 5998 are great for slam and dynamics, but lack overall air and depth many times, IMHO.  I find that neither of these can touch the sound stage and air of the 6080 though, with an exception maybe with the RCA gray plate.  I do find the 6080s to be more polite, but with added air as well as bloom, if at the expensive of slam and weight, especially compared to the 5998.  You really have to be a little careful though because I've found that several brands/batches of 6080 are a little light in the low end.  I've never liked the GE 5 Star and RCA (except for older JAN RCAs) for this reason, and while the Tung-sol and Bendix WB build with cast iron plates can give nice highs, great mids, and enough bass for most music, at times they can sound a little thin in the upper mid-range.  For 6080, I prefer the mids and extra airiness from the European variant, the CV2984, with Brimars and British Military being very nice if you can find them.  Then there is the GEC 6AS7G, with comes as a coke bottle as well as a 6080.  I purchased one about 5 years ago for a great price, at $80 shipped NOS, however it was damaged in shipping.  Supposedly they have the same internal structure, but the coke bottle 6AS7G generally commands higher prices.  I wish there was a little more variety with the 6AS7G type, but the 6sn7 is truly a monster when it comes to different brands/builds and one of the main reasons I bought the amplifier and have kept it for so many years.
  
 The 6sn7 has a ton of brands/designs, which makes it a favorite tube of many rollers.  Within the 6sn7 type there are different designations separating designs by the addition of functionality and/or purpose.  Some have heaters and warm up quicker for example.  While there are differences between these types (designations GT, GTB, A, W, etc.), different brands/years used not only different components/designs, but also different materials.  All of this can affect the sonic characteristics of the sound, but I've found that price isn't always a true determinative value of quality; like a lot of things.  Many tubes that I purchased on the cheap have really impressed me, at least in my system and to my ears.  Some are definitely worth their money, such as the Tung-sol Round Plate, or the metal based and plastic short bottle 6SN7W, which can really go for a lot.  However, others such as the early Hytrons/CBS, or the militarized _micanol _bases can be had for cheaper prices and still sound very good.  For example, one little generally unknown tube, the 60's Brazilian Aluminum RCA 6sn7gt, is very different than any other 6sn7 I've tried, closer to the Tung-sol "Mouse Ears" than anything else, but still very different.  This Brazilian metal design can add a ridiculous amount of air and seems to push the sound out in all directions by many feet; very good with chamber/orchestra and even live acoustic.  Then there is the European variants like the CV1988 and B65.  I've never had the pleasure of trying a B65, such as the Osram/Marconi brands, as they can be very expensive.  I do have a Brimar CV1988 black glass that has very good mids, but seems to cut off too much of the highs and also be a bit sibilant.  Others can work in place of the 6SN7, such as the ECC32 and ECC33, in most applications, with more impactful differences than within same family.
  
 The 6AS7G/5998s really don't have a whole lot of different manufacturers out there, at least compared to others, there is more as a 6080 variant, but still not a ton.  On the other hand, the 6SN7 is a widely popular tube, even during it's day, and was made by many different manufacturers/brands, which in most designs/brands provides enough variation to warrant large tube threads/discussions/rollers, not to mention the varying degree of prices asked for on-line and in auction.  However, I do believe everyone's mileage may vary as ears and systems are different.  There are also a lot of re-branded tubes that not only sound exactly like their OEM brothers, but because so generally go for cheaper prices.
  
 As far as the TU-8200DX, there are a ton of different actual variants of tubes you can use, regardless of brands, and the differences between them are not always subtle at all.  The KT series sounds very different to the EL34, or even the 6L6CG.  However, at times I've found differences even within manufactures, with the blue glass Telsa EL34 being much brighter up top with great air, but a little thinner and lighter in the low end than the Tesla yellow seal clear glass.  GE and RCA 6L6GCs are similar, but the GEs tend to have quite a bit of bass compared to the RCA, which I found is more balanced, similar to the 5998 and what it does to the speed and articulation of the notes.  Within these types there are also many new production tubes, some of which are really only geared to guitar amps, which can really eat up tubes during live shows.  Since they are constantly going through them, they need more inexpensive new production brands.  Most of the time these are Russian, such as Svetlana's, JJ's, or the re-branded Tung-sol's.  Others such as the Russian re-brand of Genalex's Gold Lion brand give better sound quality, but at a higher price.  Russian manufacturers bought the rights to use the names of classic out of production NOS types, building them to the specifications of the original designs (or at least they claim).  However, many believe that most of these do not sound as good as their original NOS counterparts, and the cheaper brands aren't seen as reliable.  Many like the Russian Gold Lions, as an inexpensive alternative to the NOS original.  The KT88 GEC's or original Gold Lions can bring large prices at $200-$300 a tube, which is a product of both their scarcity and sonic enhancement; arguments for both. Other new production, such as Psvane and Shuguang Treasure ask higher prices for claimed higher fidelity; many have had great results.
  
 There are also many variants for the 12au7 and even more brands, which can either be dirt cheap or command very high prices.  With the TU-8200DX, I find that the differences between signal tubes can vary from subtle to slightly impactful, with again the more impact coming from variants than individual brands.  The Tung-sol black glass provides a very nice full sound, while some of the GE's can sound a little thin.  I've also enjoyed the CBS/RCA black plates, with the RCA clear glass being very clear and detailed, but a little thin with certain songs.  Then there are the variants, such as 12au7a, 6189, 5963, 5814, 7730, 6680, ECC802S, 7136, ECC82, 13D5/4/8, and probably a lot more I missed.  Within a few of these variants there is only really one brand, sometimes with a few re-brands, but generally the 12au7, 12au7a, 5814, and ECC82 have quite a few brands.  Another example, I've been using some Tesla silver pin ECC802S recently and rolling Siemens, Valvo, Mullard, and Philips EL34s; I'm getting some really great smooth detail with great clarity in the mid-range, very nice.  There are the more expensive Telefunkin gold pin ECC802S, that are supposed to have better clarity, but only these two brands.  While the different brands of EL34s listed all have varying degrees of detail, air, and sound stage in the mids/highs, but not huge differences.  So, a bigger impact to what I'm currently hearing would be to change to say a KT88 and a Mullard Blackburn ECC82.  I believe this is due to the increased resolution of the TU-8200DX over the 336se, as the differences between these similar EL34 brands seem to have more of an impact than say a GE 6080 5 Star gray plate and an RCA orange label black plate 6080.  Now, putting in a Telefunkin EL34 or a SED Winged "C" or even a Groove Tube, will give me a more intensely different flavor.
  
 From my experience, I would say that it depends on the types of tubes used and the resolution of the amplifier in the end, which both are a testimate to good design.  Some designers have chosen to go with newer production tube implementations, utilizing new production Chinese and Russian types, while others have kept the NOS market very much alive today by choosing types such as the 6sn7 and 6AS7G.  With a ton of NOS options as well as plenty of new production today, I'm sure glad Mr. Fujita picked the ones he did for the TU-8200, even though my wallet may not be...


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## Effusion

twizzleraddict said:


> Great review.
> 
> I heard this at a local Vancouver meet and was amazed by the musicality of it. First listen, the music sounded extremely warm and inviting, drawing you in. Victor was playing CDs with this 47 Treasure CDP through the amp and driving a pair of HD650s. I'd be pretty happy with this combo and not want for more.


 
  
 Thanks!
  
 I think I remember Victor telling me about that meet, right around the time my FET went out.
  
 I agree, the 47 Treasure CDP really sounded good.  I wish I knew more about the DAC inside; Victor did mention that it was more of an advanced build and it does look a little complicated.  Very cool design and sounded amazing when paired with the TU-8200 and running HD650s.
  
 *EDIT, added some pictures of the 47 Treasure below from RMAF, the second picture it is next to the TU-8200, with my HD650's plugged in... the CD spins outside of the unit, very different/cool design that sounded very good with this combination!
  


  
 BTW, really enjoying a nice pair of KT66 IEC Mullard Clear Glass with Tung-sol black plate black glass 12au7 with both rock as well as piano right now.  Very nice speed, depth, impact, and tone, with just a little sparkle in the highs, I believe due to the tung-sols.


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## vkung

_For the TU-8200 the headphone circuit is not exclusive and does not bypass the tubes or output transformers. Mr. Fujita our chief designer simply made the headphone terminal an integral part of the tube amp itself, adding only three pairs of resistors to the signal path. _


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## vkung

The photos were taken from 2014 AXPONA.   Bob's devices is using TU-8200dx to demo his setup transformer. In the past he used Schiit.


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## vkung

The size of  1/w Amtrans  carbon film resistor is bigger than stock 1/2w metal film resistor.  To replace the existing 1/2w metal film  resistor with Amtrans carbon film resistor, you will need to adjust the angle of the Amtrans carbon film resistor to install it on the PCB. This picture shows how it should look once bent and installed properly.


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## vkung

Elekit does not recommend adding a switch to change the output mode. 
Changing the output mode while the power is ON could damage the tubes and output transformers.
  
  
Photos are from the following link: The site administrator has a lot of  interesting ideas to modify TU-8200
 http://mtomisan.cocolog-nifty.com/blog/2014/02/tu-8200-53d5.html
  


  
  

  
 The following are photos are from 6moons TU-8200DX review


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## Effusion

Thanks for the link!
  
 Very interesting modifications, but as Victor points out you need to be careful to not change the jumpers while the amp is turned on.
  
 Although the different output modes is a really cool feature of this amplifier, I think it is probably best to stick to one output mode depending on your tastes as well as the sensitivity of your speakers.  Since the review, I have played around a little with the Ultra-linear mode and while I've found it to have a very nice sound/tone, the rolling of different types of tubes has given me more of a change, allowing the tweak-ability of different sound signatures that I enjoy.
  
 Still a very interesting modification and site; too bad I don't know Japanese!


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## fccn75

Vkung, I am seriously considering this amp and like to ask if TubeDepot is authorized seller of this amp?


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## vkung

fccn75 said:


> Vkung, I am seriously considering this amp and like to ask if TubeDepot is authorized seller of this amp?


 
 Yes, Tube Depot is authorized seller of TU-8200.


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## vkung

Finally, I installed Amtrans AMCY Oil coupling caps with TU-8200.  This is the joy of DIY. You can improve the sound at your discretion and budget. 
  If you have a bigger budget you can use Amtrans AMCA (copper foil  $60 each ). I think the AMCY ($25 each)  is good enough for TU-8200.
 I will attend the SFO Audio show to spread out this JOY.  You don't need big money to have excellent sound
 Please trust your ear rather than reviews. DIY is my passion..


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## Greg70

For those who’ve wondered about the Elekit with lower impedance headphones, here’s my experience with Grado GS1000i’s:
 After reading Effusion’s review of the TU-8200DX, and some of the others on the web, I decided to take the plunge and build one of these. I’ve done a fair bit of DIY electronics work in the past but hadn’t had the soldering iron fired up for a while, so the chance to build an amp myself, have some understanding of the circuit, and be able to tweak it a little if I wanted to appealed to me.
 I built it over a several sessions, but I’d say it only took about 6 hours from start to finish.. and when I first fired it up with the supplied tubes (no-name chinese 12AU7s and EH 6L6GCs) in Ultra-Linear mode, I’m glad to say everything worked and I was impressed with what I heard. It was detailed and warm, with the bass response notably deeper and fuller than I’d heard with other amps.
 I found out fairly soon that with the Grados at the levels I like to listen, the bass was just too much and I couldn’t listen for long. It sounded great, but my ears couldn’t take much of it. I switched to Triode mode and things got better, and also tried a pair of PSVane KT-88s, but for me the bass was still overwhelming everything else a little.
 Next I went on a bit of a buying frenzy with the 12AU7s and rolled a heap of different brands and types through (I’ve got Amperex 7316s in there now.. a great choice if you can find good ones). They all had their own sound but they didn’t change the basic character of the amp. Then I decided to try some EL34 power tubes, not expecting anything much, but what I got was a major transformation. Suddenly the bass was perfect, plentiful and dynamic, but no longer “too much” for comfort.. and without the bass taking the main stage, everything else came to life. I could hear every detail, vocals, cymbals, guitar, everything sounded balanced, detailed and lively without a hint of harshness. The soundstage, which was already good, opened up even more.
 I’d say all this detail was there before, but the bass was dictating the volume and so the mids and highs were effectively turned down.
 In hindsight, the answer was there all along, and if I’d bothered to read the original post by ‘Effusion’ a bit closer, he’d already laid it out when he said: “If you tend to find yourself opting for less bass in your listening preferences you can try a pair of EL34s for some extra mid-range detail”… and, “I have found that EL34's tend to be a little more shy when it comes to the bottom end than KT88s or KT66s, however they have a beautiful mid-range and probably the best sound stage out the variants I've tried thus far”.
The GS1000i’s have that boost in frequency response at around 100Hz and 7000Hz, and the result is that they seem a bit recessed in the mids. The EL34 is a tube with strong mids and a bit less bottom end than the 6L6 and KT types, and the result in this amp is pretty much perfect for me with the Grado ‘phones.
So with a little tweaking and tube rolling, I really couldn’t be happier and my plan is to just listen and enjoy now (well apart from a bit more tube rolling). The Elekit sounds absolutely superb now, and every question I’ve asked along the way has been answered almost immediately by Victor and/or designer Mr Fajita. 
It was a fun and rewarding build, but if you’re using Grado’s I highly recommend you go with EL34s unless you’re a dedicated basshead.


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## Effusion

Hi Greg,
  
 Thanks for sharing your experiences with lower ohm headphones, such as the Grados, when paired with the TU-8200.
  
 My sediments exactly; the EL34 is a great sounding natural, but neutral, tube with great air/soundstage and mid-range detail.  If you think you may benefit from a little more sparkle on the top with even more of a slight decrease in bass presence, the Tesla EL34 "Blue Glass" NOS variant may be worth a try.  To me they do everything the clear glass Telsa EL34 "yellow" labels do right, but with just a bit more sparkle and a little less bass; very nice when I want just a bit more on the highs with certain genres.
  
 The Telefunkins and Philips Metal Base EL34s are often regarded as the best in this type, however they can demand quite high prices (I haven't heard either as of yet).  I've found the Mullards, different versions/getters, but all manufactured at the Blackburn factory, to be very nice overall, with great speed/slam/dynamics, but with a bit more bass presence and impact than other variants of the EL34 type.  Another great option could be the SED Winged "C" EL34, which are more plentiful and generally a bit cheaper (shop around), but with good all around performance.  NOS EL34s can be a little harder to find and bit more expensive because there are fewer out in the marketplace; plus, many boutique guitar amplifiers take these tubes as well, so you have to compete a little with others.
  
 As of today, I've tried ~250 different tubes, and I would say ~120 different variants/brands, in this amplifier and I've found that the tweak-ability of the sound signature is almost endless.  I may put together a thread about my tube rolling experiences and impressions once I get some more time and get my collection more organized.
  
 The great thing about this amplifier is the adjust-ability/tweak-ability.  Now that it appears that this amplifier does match very well to lower ohm headphones, in addition to higher ohm, and that the automatic bias feature makes the process of changing out different types of tubes so easy, I'm sure you'd be hard-pressed to find a headphone that doesn't, at least decently, match easily to this amplifier.  In my opinion, this is the ultimate test in good design and also a true testament to the talent of Mr. Fujita of Elekit.
  
 I'm sure you'll be enjoying this amplifier for years to come! 
	

	
	
		
		

		
		
	


	




 
  
 EDIT:  I think you also bring up a good point that I'm not sure if I went into much detail about in the review; while rolling signal tubes can give a nice slight variation to the sound/texture, they are more like an RCA cable swap, while a big change similar to the swapping of quality power cables, the power tubes give much more of an impact to the overall sound signature, bigger and more impact.  I believe this is mostly due, in part, to the fact that you are really only using 12au7s and slight equivalents that most of time are based on it.  Now, there are some variants that make significant changes, 7316s and such, but they can be hard to find and usually from one or two manufactures.  The power tube variants, on the other-hand, are much more unique among both types and manufactures.  I wish I knew more about how the automatic bias feature works, but I do believe most of the variation in bias it is handling is from the different power tube types being swapped, who are close but not exactly in spec of each other as far as the bias; could be why it more impact?  So, I've also found that the impact of rolling the power tubes makes much more (most of the time) difference than the signal tubes in the TU-8200.  Thanks again for sharing and keep us up to date on any other findings!


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## Greg70

Wow, that's a serious tube rolling effort Effusion. You must have just about worn the sockets out !
  
 Thanks for the EL34 suggestions.
 The ones I tried were the Mullard re-issues - because they were cheap and available, but once I realised this was the tube family I liked I bought a pair of Telefunkens off eBay (haven't arrived yet).
 It came down to Teles or real (NOS) Mullards, so I'm hoping I made the right choice.
 I'd love to try the metal base Philips, but the prices are crazy. Has anyone tried the Psvane replica - EL34PH ?
  
 Have you settled on a favourite 12AU7 ?
  
 I hope you get time to do that tube-rolling thread


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## fccn75

Just curious if any of you who has completed this kit experience any microphonics when inserting headphone into the jack or tapping/touching the chassis.  Mine does it.  Each time I touch the volume or anywhere on the chassis, I experience microphonics.  In short of removing the enclosure, I looked at the tube sockets to see whether it was making contact with the chassis but doesn't seem like it.
  
 So far, audio bliss with all my headphones - LCD2.2, HD800, HE-6, with the exception of Fostex-TH900.  The best of the bunch with vocal music is the LCD 2.2 to my ears which for the first time I am experiencing a huge holographic image and a very rich and clear mids much more so than on my other diy - SOHA2.  It is a completely different level of sound.  What's really surprising is this TU8200 at UltraLinear can drive the HE-6 via 10 ohm resistors paralleled at the speaker outputs to a ear shattering level at 12 o'clock!
  
 Will be trying the suggestions on tubes but like to spend more time with the stock tubes for the time being.


----------



## Greg70

fccn75
  
 It sounds like you have a very microphonic tube in there, most likely one of the 12AU7s, and yes I've had it with a bad tube.
 Remember the sockets, boards and chassis are all solidly attached to one another so tapping the chassis will transfer to that tube even without the socket directly touching the chassis.
  
 You can generally locate the bad tube by lightly tapping it with a fingernail with no music playing.
 Even a good pre-amp tube will give a slight ping when you do this, but you'll know the difference with a bad one.


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## Effusion

Hi Greg,
  
 I think you made the right choice, upon reading what sound you are after.  I've tried 3 sets of Mullard NOS EL34s, different versions, and they all seem to have a bit more bass presence than my other EL34s.  The Telefunkin smooth and ribbed plate 12au7 are a little softer than most 12au7s, with a little less bass presence, but really great air, soundstage, and very nice mids; so if the EL34s are anything similar to them, I think you'll be happy with the purchase.
  
 One of these days I'll try to get a better handle on some of the impressions I've had... I'll try just about any tube once!  I actually do have high quality socket savers to help with ware, etc., which actually work well when rolling the EL34s.  Most of the NOS EL34s I have don't tapper off at the end of each pin, like other tubes do, so it can be a little harder on the sockets when rolling in and out as they don't slide as easily.  The socket savers really help and don't appear to impact the sound; the ones I'm using are ceramic bases with heavy duty gold sockets.
  
 As far as my favorite 12au7... it's hard to tell.  I really like the Brimar 13B5s, the Raytheon 7730, Mullard 12au7w (militarized), Amperex Bugle Boy and Orange Globe, Siemens, and even the RCA Clear Tops aren't too bad.  I actually need to spend so more time with some of the other off brands, but a few have actually really impressed me as well.  I guess it all depends on my mood and what style of music I want to listen to... gives me a reason to have so many!! 
	

	
	
		
		

		
			




  
 Let me know how those Telefunkin fare with the Grados... hopefully better than the new issue Mullards, but from what I've read, that while the new issue Mullards aren't terrible, they lack a bit of refinement and detail, among other things, but I have not heard a pair of them yet, surprisingly.


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## Effusion

greg70 said:


> fccn75
> 
> It sounds like you have a very microphonic tube in there, most likely one of the 12AU7s, and yes I've had it with a bad tube.
> Remember the sockets, boards and chassis are all solidly attached to one another so tapping the chassis will transfer to that tube even without the socket directly touching the chassis.
> ...


 
  
 I agree with Greg, it sounds like it is probably a microphonic tube.  At least, it's the best place to look first.
  
 In the past, I've actually enjoyed a few microphonic tubes, they can really allow the sound to open up and give a boast to the air around notes.  However, they can mess stuff up when you use speakers instead of headphones, as the sound waves will rattle the tube while it plays.  Some have had success with tube dampeners, but if it isn't horribly bad, there really is no need with headphones.  Plus, damping the tubes tendency to vibrate will make the tube sound a little more solid state in some cases; could be a good or bad thing depending on your preferences.  However, a really badly microphonic tube may have other issues with it, so it's best to generally not use them.
  
 You could pick up a pair of RCA clear top 12au7s to test... they tend to do quite a bit right and are probably one of the cheapest NOS versions.  The 12au7s that shipped with my amp are only branded as made in china, in red, but I only used them to test when my FET blew; I don't remember them being microphonic however, but it varies from tube, not manufacturer.
  
 EDIT:  If you think it is one of the power tubes, then you might want to be a little more careful when considering which to buy/choose, as they sound quite different from each other.  As far as cheap NOS, try to pick up a pair of GE 6L6GC, if you can get a good price on them (less than $50 is good).  I've found them to be quite nice when you want some more slam and power to the sound (I actually prefer them to the RCA Black Plate 6L6GC at over $100 pair).  Anyway, let us know what you discover... hopefully it's easily fixable.


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## fccn75

Greg70 and Effusion, thanks for all your suggestions.  I will try a pair of another 12AU7's and as a matter of fact just happen to have a few sets available.  
  
 I just cant' imagine more slam with the change of the power tubes, it's already fantastic as is minue the microphonics which is really not a big concern since my primary output is via headphones.  Very rarely do I use speakers nowadays - too much to correct in the room acoustic equation and neighbors who are just dry walls away!
  
 Anyway, I will eventually get to the power tubes but it's still too new with only 20 hours of playing time.  BUT audio bliss regardless!


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## vkung

This is the magic of tube amp...


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## Effusion

fccn75 said:


> Greg70 and Effusion, thanks for all your suggestions.  I will try a pair of another 12AU7's and as a matter of fact just happen to have a few sets available.


 
  
 You're welcome... I hope that switching the 12au7s will correct the issue, but if not it may be one of the power tubes.
  
 I'm glad you're enjoying the amp already at 20 hours!  Over the next 15-20 you might start to hear the sound open-up even further, I did; at about ~35 hours I rolled out the Electro-Harmonix 6L6GCs with a few different variants, including the GE and that's about when the lows showed up and the sound got both more tighter and more open, both in a good way.
  
 The EHs aren't really terrible or anything, I've since listened to them again after burn-in, and they appear to me to be more shy than other 6L6GCs, but with very good highs and upper mid-range compared to others of the same type, albeit with less detail/resolution and low end, when compared to other 6L6GCs, anything from the KT family, many EL34s, and also several of the smaller production variants.
  
 If you end up deciding to try out a different type of power tube after burn-in, let me know and I might be able to give some recommendations or maybe a few pointers.


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## fccn75

Yes, you were all spot on for the microphonics - the culprit was the left 12AU7.  Changing that to another set I have on hand solved the microphonics with even a firm tap with hand does not induce any noise as it was did.  Just surprised to find the brand new stock ones has that high of a microphonic problem.  Thanks for your help and it was very much appreciated!!
  
 Also, just fyi, vkung is absolutely great in support as well with such quick responses!  I made the right choice in this purchase and am in music nirvana 
	

	
	
		
		

		
		
	


	



  
 Will give the stock power tubes >100 hrs before trying some of the suggestions Effusion made and will report back soon.  Thanks again, ALL.


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## JK-47

I purchased this kit over the holidays, as I was in my hometown of Vancouver, and hoped to save on shipping. I picked up the amp kit from Victor at his residence, he was fantastic to deal with.
  
 It took me 8 hours to get everything together, but the LED did not come on! No smoke or burning so I let it warm up for 30 minutes under my careful watch. I functioned checked all the inputs, the DAC option I added, the speaker outs, and headphones. Everything worked like a charm!
  
 Victor quickly respponded to my email and said I had probably put the LED in wrong ( I was sure I didn't), so I remounted the LED, and it worked!
  
 I'm beyond impressed with the fit and finish of the kit. It feels and sounds like it's more than the sum of its parts...
  
 This is my first tube amp, and I'm in love with the sound even though I hardly have 3 hours on it. I can't wait until I have more hours of burn in, and play with different tubes...


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## Greg70

Congrats on your build JK-47.
  
 I suspect you'll find that as you roll tubes, discover the tube family that suits you and your headphones, and then find the particular tube from that family, the sound will go from good to amazing. It did for me anyway.
  
 Just a follow up from my previous posts.. with Grados I liked the EL34 family by a large margin. They have great mids and you can somewhat adjust how much bass and top end you like by switching between Triode and Ultra Linear.
  
 Unfortunately the Telefunken EL34s didn't do it for me. High quality and very accurate I'm sure, but they seemed clinical and lacked character.
 I then tried a pair of NOS Mullard EL34s (XF2), and they were unbelievably good (the reviews and hype are true), and my EL34 search ended there.
 If you decide to try these, my suggestion is to make sure they have good flashing. There seems to be a lot of used Mullard EL34s for sale with flashing that is getting thin and brown. They still work but they get weak fairly quickly.
  
 For the 12AU7, I settled on Amperex 7316 for a long time, and they're a great choice and very hard to beat.. but recently I tried a pair of Tesla ECC802S and I was amazed to find that they seemed to have more detail and a better soundstage than the Amperex. I was hearing things I'd hadn't heard before.
 My disclaimer to this is that the Teslas have a bit more on the top end, and at 52 years old and having spent a fair potion of my life around noisy machines, it's possible I've lost some hearing in the higher frequencies and the Teslas just helped with that.. so YMMV. 
  
 I'd love to hear from someone who's tried some of the high end current production tubes like PSvane, because the NOS tube hunt sucks and you never quite know what you'll get.
  
 Anyway, good luck and let us know your results.


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## fccn75

Also congrats on build JK-47!  I have been enjoying mine on a daily basis and all I can say is it's one of the best experiences I have in headphone listening.  
  
 However, I do suggest you take your time and experience the stock tubes for some sort of reference for at least 100hrs as others have suggested to me early on.  The sound signature will then be readily apparent when you start rolling tubes whether input tubes or output tubes.  With this early stage of burn-in especially for tubes, it may have enough variables to alter the perceived sound to another level.
  
 But regardless, I think you will enjoy this as much as I am on which ever set of tubes you choose, this amp is that good IMO!
  
 Also, there is another area of sonic difference one can try on the TU-8200 - the three modes of operation:  Triode, UltraLinear, and Pentode.  I have been using the UL since the kit was completed and only switched to Triode days ago.  My initial impression for the Triode mode is that it's not as forceful insufficient slam?? i.e orchestra at the peak of a passage.  But will leave it on this mode at least another 40hrs before going back to UL.  
  
 From the description on the manual, I had expected Triode to be the best mode of operation.  With my ears, however, it "seems" like the UL mode offers better sonics especially on initial attack of acoustic instruments and a more of the sustained decay properties i.e. guitar passages.  I don't know...
  
 A question for all owners of 8200, which mode of operation do you prefer?
  
 Btw, I wanted to also share with you all that I had one problem regarding the input connectors.  We all know that the input 1,2 connectors on the PCB are soldered onto another PCB perpendicular with solder flow specifically "L"  shaped at the connection points.  This unit is mounted via 4 screws onto the chassis.  Recently with the cold winter weather, I was experiencing intermittent drop outs via one of the inputs.
  
 Pushing on the connectors solved the drop out but returns as soon as left alone - so figured was cold solder.  BUT what is interesting after removing the top was that these two PCBs were not exactly aligned 90* after finishing on the rear cover causing stress on the solder points.  So these solder points cracked causing the intermittent physical connection.
  
 All is good now after resoldering the "L" parts while IT WAS SCREWED DOWN otherwise fastening back to the rear chassis will result once again physical stress.
  
 Thought I mention this for what its worth.


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## JK-47

Thanks for all tips Greg70 and Fccn75!!!
  
 I have been running the amp in UL mode since the very beginning, I don't plan on changing it until at least 100 hours. I have almost 30 hours on it as we speak, I leave it running with a set of headphones and a Sansa clip+ while I'm running around do other things (assembling Fostex 166en folded horn speaker enclosures .
  
 Great trouble shooting on the "L" solder joint Fccn75. That's good to know...
  
 I'll be ordering some tubes in a few weeks to start the auditions, maybe some NOS GE or RCA 12AU7's, and some Gold Lion KT88's and NOS GE 6L6GC's. I like a bit of body and bass in my music.
  
 Will update soon...


----------



## Greg70

A sad day for me.. I bought some supposedly NOS EL34s off eBay.
 I fitted them yesterday and on power up there was a flash and the magic smoke.
 It turns out the seller had repaired the center locating pin in the tubes, and one of them was in the wrong position 
	

	
	
		
		

		
		
	


	



  
 I'm hoping it's just a resistor and not the power supply that was damaged, but at least I should be able to repair it myself rather than sending it somewhere.
  

  
 I can't seem to post an image here, it says my account doesn't have permission. Does anyone know why.. maybe not enough posts ? _[Mod Edit: Try now.]_
_Thank you.. pics working now._


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## vkung

The bad tube is drawing too much current. You need to replace  the  FET filter and  the resistor to fix the problem.


----------



## Effusion

Greg70,
  
 Sorry to hear about your amp.  NOS tubes on Ebay can be hit or miss, but incorrectly repairing a center pin is dangerous to an amplifier, did the seller at least refund your money?  Since it was a problem with their repair and if it was listed as working correctly, to me they should help you out beyond a refund... not good.
  
 I've had a few duds in the past and one 6080WB that flashed and the plate collapsed after about 5 hours of use, but never any smoke, etc.  When my FET blew, no flash nor smoke, the sound in the left channel just quit and the LED on the amp turned purple.  Later I found out that the tube was as NOS as you could get, it was just poor judgment on my part for trusting the equivalent tube section of the radio museum site and not thinking; the tube type I used was out of spec for the amp.
  
 Hope you're able to do a quick and easy repair... looks like the socket might have gotten a little fried; maybe a chance to upgrade the sockets.  I really like the heavy duty ceramic with gold connectors, but they can be a little hard to find.
  
 JK-47,
  
 Congrats on the amp and the build, as you acquire more burn-in you'll enjoy the amp even more.  I've found that the GE 6L6GC's do have more body/weight than other 6L6GCs, including the RCA black plates, which I don't think are worth the money.  A good nice NOS pair is worth it for ~$55 or less and is a good starting point for tube-rolling.  I did however find the GE 12au7s to be a little thin, not as much as Telefunkin smooth plates though.  A good cheap 12au7 to try is the RCA clear top, or if you want a little more finesse, maybe try a Mullard our Brimar B series. All have nice full mids, etc.
  
 fccn75,
  
 I share your enthusiasm for the amp and I'm glad you are enjoying it!  I'm going to have to try out UL mode soon, I've been using Triode since the beginning, since that is what I'm used to, but I've heard good things about UL as well.  Also, thanks for the info on your experience with the solder and the PCB boards... I hope I don't run into this problem, but in case I do, I'll now know what to look for.


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## JK-47

Greg70,
  
 Sorry about the amp... Do you have parts for repair on the way?
  
  
  
 Effusion,
  
 Thanks for the words of wisdom. I can't find a pair of NOS GE 6L6GC's on ebay for less than $100+, a few used pairs around $60... After Greg70's experience, I'm now a little leery of older tubes. Do you have any recommendations for first class/honest sellers?


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## Greg70

Yes the NOS tube game can be tricky and I wish I could find new production tubes that sound as good.
 I'd like to try the PSvane EL34PH, but they cost about the same as NOS Mullards and I've seen reports of early failure and life expectancy of 2-3000 hrs compared to maybe 8-10,000 for a Mullard.
  
 There are lots of used tubes sold as NOS just because the test figures are high but it doesn't make them NOS.
 I was lucky to get a pair of real NOS in the box Mullard EL34s for a decent price off eBay (marked Valvo military), they sound amazing and the latest purchase was an attempt to have a spare set on hand as the prices keep going up.
 I intended to just confirm they were good and then store them away, and I was devastated when they smoked my beautiful amp.
  
 JK-47: I have the resistor I need and a set of FETs on the way as Victor has suggested I just change all 4 of them - the FETs are only 50 cents each.
  
 Effusion: Thanks for your concern.. the seller has admitted that it was his mistake, and said that he'll refund for the tubes and also pay for the cost to repair the amplifier.
 The tubes were sold as NOS and tested, but he obviously didn't test them after the pin repair.
 I already have ceramic sockets, but most of what you see in that photo is just powdery carbon that wipes off, so as long as the board isn't burnt I should be good. It looks like that resistor got pretty hot for a second 
  
 I guess the lesson is that if you want to use NOS tubes, you're really better to buy from a reputable company that tests and matches the tubes from a batch.
  
 The only good thing in all this is that having built the amp myself, I feel confident in repairing it myself.
 Being in Australia, it's not an easy thing to send an amp back for repair.


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## Effusion

Always glad to help; even though the destination is what we focus on, the journey is the fun part!  
	

	
	
		
		

		
			




  
 Sometimes it can be difficult to really know what you are buying, especially from eBay, but the bay has the best prices and the widest selection at any one time.  As far as sellers, there are just too many in general to give good recommendations, but if they have 100% positive feedback, a good calibrated tester, and primarily sell tubes, you shouldn't have any problems if issues arise.  Most are sold "as is", but I've had 2 that were damaged in shipping and both times I was refunded.
  
 As far as the GEs, they can go for as much as $100 for even a used pair, but you shouldn't pay those prices, as they can be found cheaper.  Even though we all use the term "NOS" as meaning new, most NOS labeled tubes on eBay are really not brand new, but generally slightly used, or at least test a little weak.  Also, even a tube that tests beyond the specs of NOS on a tester, does not mean it was never used, and even some that test high are actually at the end of their life.  In general the tube strength is a good indicator, however other tests, such as the Hickok life test, can sometimes tell you more about how close to the end of its life it truly is (I had several that had high emissions, but very bad life tests).
  
 Quickly scanning some of the current auctions, a few below may be worth the money, and waiting to get an idea can also help, as there are always a few up for auction:
  
 This seller tests with an Amplitex At-1000, which is a nice newer tester, and he sells a lot of tubes with 100% feedback.  They may not be exactly NOS, but are pretty close:
http://www.ebay.com/itm/1959-G-E-6L6GC-MATCHED-PAIR-side-getter-U-metal-on-top-Tested-and-Guaranteed-/321640046111?pt=LH_DefaultDomain_0&hash=item4ae33d9e1f
  
 Might not be as good as the pair above, but the seller sells a lot of tubes... check out the negative feedback to get a better feeling:
http://www.ebay.com/itm/Pair-of-GE-6L6-GC-Grey-Plate-Dual-D-Side-Getters-90-rating-/141538185985?pt=LH_DefaultDomain_0&hash=item20f4555301
  
 Not my first choice, but would need to know more about how they were tested (tester, readings, etc.):
http://www.ebay.com/itm/Pair-GE-6L6-GC-Double-D-Getter-Power-Tube-Amp-Tube-Tested-GOOD-/301484081447?pt=LH_DefaultDomain_0&hash=item4631da0127
  
 One thing to look for is rebrands, GE rebranded the 6L6GC like crazy for guitar amp manufacturers and essentially they are the same tubes, but since they don't have the GE name, tend to go for less.  I believe GE actually only rebranded the top tubes of this type for its customers, so you may be getting better quality tubes anyway.  If all else fails, could be worth it:
http://www.ebay.com/itm/2-x-6L6gc-GE-Tubes-Tested-Strong-DD-Getters-Round-Spacers-Wurlitzer-Match-/281537139096?pt=Vintage_Electronics_R2&hash=item418cebd198
  
 Now, I'm not too sure about the differences between the square and side circle/halo getters... I have both, but have not spent any time trying to tell any differences.  Generally they are made with halo getters I believe though, but it is probably just separate years of manufacture, slightly different designs.  In the past, I've tend to prefer square or "D" getters a little more than the circle or saucer, at least most of the time, however it really is tube specific and generally when they do differ, something else also differs, adding to the perceived change.  So, in short, hard to gauge without trying to.
  
 No worries, as long as the tube hasn't had the guide pin repaired incorrectly, you shouldn't have a problem quite like Greg's.  I've had tubes not work, fail while on, etc. but they did not damage my amp or headphones (as a precaution, I always clean the tubes/pins, try them initially without my headphones plugged in making sure both filaments light up, and then test for microphonics or noise using the volume pot; all before playing any music).  I even listen to them while I turn the amp on as some have convinced me that the noise they produce at start-up might damage my phones over time.  I've always ended up not using them, even though one pair, at one time, was my favorite until one tube went out; just made sure I unplugged the phones when turning on the amp for a few seconds when using them.  The out of spec tube that blew my FET is a different story though, shouldn't have even tried it, and also, if the pins are incorrect because the guide is missing, you will definitely have a serious issue, NOS, new, old, doesn't matter.
  
 Hope that helps!


----------



## Effusion

Greg70,
  
 Glad to hear the seller is trying to make it right... he/she probably feels pretty bad for doing the repair without paying absolute attention to the pins; never a good thing.
  
 You are right about NOS tubes, eBay is hit or miss at the end of the day.  However, the prices some stores charge is outrageous and I've actually spent more thinking I was getting a better tube, when in fact I really don't think I did.  If you start to get a little crazy about tuberolling though, the best thing to do is just to buy a tester, have it restored/calibrated, and test the tubes yourself before trying.  At least before putting questionable tubes into very expensive equipment that you might not know how to repair.  Hickoks are generally some of the best testers, but there are other good ones as well, mostly from decades ago; there are even cheap ones that will only just tell you that the tube won't blow your amp, at least at first.  
	

	
	
		
		

		
		
	


	



  
 Nicely done on the Valvo pair.  As long as they have the "x" stamp with a number towards the base and the right plate structures, most have halo getter(s), they are Mullards from the Blackburn factory and my favorite EL34s, besides maybe some of the Teslas, which I think can have a little more resolution with a little less bass/mids, but not nearly as thin and trebley as the Telefunkins (which are crazy expensive, but very detailed and airy).  Mullard rebranded quite a few of the EL34s during the hay-day, so these are generally worth the money.
  
 As far as new stock, I just wish they weren't so expensive for ones that preform close to or at NOS levels, but with companies like Psvane, the game is changing.  However, there isn't the variety as there are with NOS, at least for really good ones.  Quite a few of the Russian tubes aren't worth it for HiFi, except some of the old SED and Svetlanas, and are only really for guitar amps that tend to blow through tubes, especially when cranked.  Some have even purchased NOS branding in efforts to confuse some and hopefully sell more, claiming they are the same, but clearly to most maybe in structure, but not in sound quality.  Also, many of the Chinese tubes have a reputation of not lasting very long and being very inconsistent in both matching and sometimes even life.  For many years the general consensus was that NOS tubes will typically outlast new stock Chinese over time and on a consistent basis, this does seem to be changing in recent years though.  However, it is probably best to buy Chinese tubes from resellers in the states who put them through the tests and match them outside the factory (some factories can tend to say everything is top-notch and matched great, when they are in fact not, or at least not using correctly calibrated equipment).  Then comes Psvane, which are highly regarded and built by guys that seem to really know what they are doing (I believe they used to help make the Chinese Treasure Tubes, when they were worth the high price tag they held several years ago).
  
 All we can hope for is that more and more people get into audio tube based gear, so that manufacturers will maybe step up their game to answer demand by producing more, creating more variety, and lowering production costs!  Is that too much to ask?


----------



## JK-47

Greg70,
  
 Great to hear help is on its way, and the seller stepped up and did the right thing !!! Wow, I checked out the price on the Mullard EL34's... maybe someday.
  
 Effusion,
  
 Thanks for the wealth of information, it's greatly appreciated. Tubes are new to me, and every bit of information helps. I'm away from home for the next 3 weeks (work), so I should have some time to browse and study some more before I make a few purchases.
  
 Thanks again, Gents...


----------



## satwilson

effusion said:


> Greg70,
> 
> Glad to hear the seller is trying to make it right... he/she probably feels pretty bad for doing the repair without paying absolute attention to the pins; never a good thing.
> 
> ...


 
 I have been watching this thread from afar for a while. I have a Schiit Lyr, and a few thousand $ of 6DJ8 variants. As a DIY guy this amp has my interest, more "TUBEY" than the Lyr. Anyway, Effusion is giving the best recommendation. Anyone who is committed to DIY tube stuff HAS TO GET A TUBE TESTER. Hickoks and Amplitrex are awesome testers, but expensive. My lowly Sencore TC154, calibrated, GETS THE JOB DONE! Emission, shorts, grid leakage, life test. Of course put in a proper tube. I was DIYing Dynakits back in the 60s. Guess I gotta get an Elakit?


----------



## bixby

Effusion was kind enough to bring the Elekit over to my place for a micro meet on Sunday.  He also brought a ton of tubes and a few other components.  Since the last time I heard the amp was Viktors at RMAF with K701s, I was excited to hear how Effusions unit would sound with his modded Senn  650s.   A carefully chosen set of tubes was installed for our first listen with the Senns.  Running from my main Mac Mini System and X-Sabre dac we were presented with some fantastic sounds.  
  
 Oh, I have to say we started out the listening with his Hartung OTL amp.  Really nice step up from both of our Darkvoices as memory served.  The Elekit was in another league entirely.  I was really impressed with the amount of space between instruments and depth we got with the Elekit.  And treble detail was excellent with no added edge.  Mids were nicely placed and no one who hears these modded 650s and the Elekit would ever say the Senns were veiled.  Bass was clean and tight with no added warmth to slow things down.
  
 As good as the Senns are with the Elekit, my newly acquired Mad Dogs were also superlative.  I have heard the Mad Dogs for years at shows and listened to them for hours with various amps that Dan and others provided.  Never did I hear such a clean and clear presentation, especially in the mids.  No darkness or laid back presentation was apparent and bass was tight and deeeeeeep.  Transients were fast and the overall presentation was one of dynamic power.  Over the course of several hours we rolled various tube combos, and all sounded great with subtle shading differences.  My favorite set was the first combo and Effusioin said he always picks what he feels might work best to start things off.
  
 In closing, if anyone has any doubts about how well this Elekit amp can drive Mad Dogs, do not hesitate to put it on your list.  It really brings the sound quality way up from a run of the mill solid state amp.  So if anyone has an itch to part with their Elekit, please PM me I would be interested.


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## vkung

Beside  HD650 and Mad Dogs,  TU-8200DX works well with LCD3 & HD800...


----------



## Effusion

Thanks again for having me over for the micro-meet bixby!  It was great being able to spend some time with the Mad Dogs and I agree, they sounded absolutely amazing with the Elekit and are well worth the price Mr. Speakers sells them for!
  
 I've actually been interested in the Alpha Dogs since they were released and have really enjoyed them at RMAF in the past, but generally I have only heard them out of a Schiit stack before.  Seeing how the Mad Dogs preformed out of the Elekit really got me thinking that this amp would also pair very well with the Alphas, which are now at the top of my list for my next set of closed cans.
  
 If anyone is interested, the 1st combo bixby is referring to was a pair of NOS Genalex Gray Glass KT-66 and a mint NOS pair of Brimar CV4003 "T" version.  The Brimars really seemed to make quite a difference compared to several other 12au7 types that we tried with the Genalex, giving the Mad Dogs an extra amount of weight and clarity, with excellent highs.
  
 In comparison to the Genalex, we also tried a pair of McIntosh KT-88 (which sound a bit better in my system), GEC clear glass KT-66 (which just didn't have quite the impact/speed/slam of the Genalex, but close), and a pair of Valvo (Mullard 3rd gen) EL34s.  All these pairs were closely matched with the same date codes, etc.
  
 In comparison to the Brimar CV4003, we also tried Brimar 13D5 (which seemed a little laid back to the CV4003), Telefunken ECC82 "Smooth Plates", CBS gray plate 12au7 (grabbed the wrong ones, as I prefer the black plate 5814W instead), and attempted a pair of Tungsol "Black Glass" 12au7s, but unfortunately I also grabbed the wrong pair as one of them had a bit of noise.
  
 In retrospect, I should have spent a little more time and grabbed a few more 12au7s and variants to try, such as the excellent Raytheon Uniline 7730 gold pin or the Telefunken ECC802, however I'm currently in the process of organizing them all better, so even finding the ones I did in time wasn't easy.
  
 In all, with bixby's great sounding system, the Genalex KT-66 and Brimar CV4003 Ts made the top of the list.  However, things could have turned out different if we were able to spend some time comparing these various combos out my DAC41 as well, but after a few hours you also start to become fatigued.  As you all know every system is different, which makes tube-rolling both fun, but also extremely challenging and difficult.  However, I do believe that this combo would provide great sound out of the Elekit in just about any system.
  
 Anyway, if you own a pair of the Mad Dogs and have been looking for an amplifier to get the maximum quality out of them, I don't think the Elekit with the right combo of tubes for your system will disappoint at all.  As for me, it was the first time I had really personally spent a good amount of time with lower impedance phones and the Elekit; others have told me how great this amp is with low impedance, but now I have proof!  It is truly amazing that this amplifier can sound so good with such a wide variety of headphones and loads and is a true indication of the extreme talent of Mr. Fujita of Elekit.


----------



## fccn75

Effusion - thanks for that wealth of info!  Really appreciate all your efforts in those tube comparisons.
  
 Vkung - I was intrigued by your previous post regarding the Tu-8200 working well with HD800.  So far I have tried onlt the Genalex KT88 with RCA clear top 12Au7 and while it does wonders for my LCD 2.2 (pre-fazor), I am enjoying the HD800 a bit less with these combination.
  
 What I hear on especially violins, the HD800 has to my ears way too much stridency to the point of early ear fatigue.  I also feel that it can use a little more low end weight when kettle drums or the voice of a tenor comes on.  Or for that matter, even voices like Allison Krauss can use a little more low end fill when I hear it.  By the way, this is with the newer HD800 with serial number in 30XXX series.  
  
 Perhaps if I may ask for suggestions on trying a set of 6L6GC?  Would that most likely synergize with the HD800 to slightly fill the much needed low end?  By the way, there are so many 6L6GC's out there and I came across a few:  Tung Sol, TAD, Wind SED?, and the GE as was pointed out a few post ago.  Which one would you all vote for?
  
 Thanks in advance, ALL!


----------



## JK-47

Effusion,
  
 What kind of socket savers do you have? Any pics of your amp with them?
  
 I ended up with GE 6L6GC's and Amperex orange Globe's. I'll be home in a little over a week to try them out, I can't wait!


----------



## Effusion

fccn75,
  
 You're very welcome, I hope the impressions of bixby and I may help you either now or down the road.
  
 As far as what to do about the HD800, unfortunately I do not have a pair myself, so it is a little hard to give a solid recommendation, but I'll try to provide some info that I hope helps.  I have not spent a huge amount of time with them, but I believe the general consensus is that when closely compared to the HD650s, they have more detail/resolution, with less low end and brighter highs, at the expense of a little fuller mid-range.  So, they may be a little trickier than the HD650s to get a fuller mid-range with less sparkle up top, especially with the added micro-detail they offer.
  
 First thing, are your Genalex KT-88 the NOS version from England, or the re-branded new Russian "Gold Lion" stock?
  
 Reason I ask is they are actually very different, giving quite a difference in sound depth and range, at least this is my understanding.  The Russian versions aren't necessarily horrible or anything and are quite commonly used, but my understanding is that they lack overall depth and are quite a bit more sterile overall, with a little extra sparkle up top compared to the NOS English versions.  However, this is what I've been told and what I've read from others, unfortunately I do not have direct experience with either, so please take that into consideration.
  
 If they are the Russian brand, than your best bet would be to try a different power tube to attempt to get some more depth and low end weight.  My recommendation, without breaking the bank, is to try the NOS GE 6L6GCs, if just to see what a difference, especially in the low end, they give your HD800s.  If they seem to have a little too much bass or seem to bloat a little of the resolution in the low end, the RCA "Black Plate" 6L6GCs are a little cleaner and more tame in the low end (but pricier).  In addition, but definitely not cheap, any of the NOS KT-66 or KT-88 should give you more depth, smoother highs, and better lows than the Russian new stock, also with more finesse, better overall sound-stage, and a more forward presentation than the NOS GEs.  There is also the Psvane KT-88, which aren't cheap for new stock Chinese, but many, including Victor, really like them and I believe they may give you a little more resolution than NOS versions, however probably with a little less of that silky smooth tube bloom sound.
  
 If they are the NOS English brand, than those are some really nice rare tubes and worth some dough, and your best bet would be to just try a different pair of 12au7s.  While the RCA clear tops are a great overall tube, especially for the price, others may give you more of what you are looking for.  I've really liked the Tungsol "Black Glass", as they have given me a stronger and deeper low end, while the Brimars and the Mullards have given me some of the best mids, with great lower mid-range, while smoothing out the highs (although maybe a little too much smoothness in the highs sometimes).  The Mullards tend to have been a little lighter in the bass than the Brimars, but some of the various types of Brimars haven't always been consistent (I prefer the CV4003, but the 13D5 and 13D4 or good to, just a little more laid back, similar to the how the Mullards are a little laid back).  The Amperex "Bugle Boy" is also a great little tube, as with all the Amperex tubes, but may offer a little more up top than down low.
  
 I hope this helps, but let me know!
  
 *Edits were made to correct Chinese to Russian, as I mistakenly referred to the new stock Genalex KT-88 as Chinese, when in fact they are Russian.


----------



## Effusion

jk-47 said:


> Effusion,
> 
> What kind of socket savers do you have? Any pics of your amp with them?
> 
> I ended up with GE 6L6GC's and Amperex orange Globe's. I'll be home in a little over a week to try them out, I can't wait!


 
  
 While I don't have any pics of my amp with them readily available, below are the exact ones I use:
  
http://www.ebay.com/itm/1pc-Octal-Gold-plated-tube-saver-adapter-for-EL34-GZ34-KT88-6V6-6P3P-5Z3P-6SN7GT-/191109289479?hash=item2c7f005607
  
 So far they have worked great!  I really only use them for some of my EL34s as many of the NOS versions don't seem to taper off at the end of the pins as other tubes do; especially the Tesla "Blue Glass" EL34s.  This causes additional ware on the sockets of the Elekit and they can also be quite difficult to get out.  These certain EL34s are much easier to remove from the socket savers as you can pry them apart horizontally outside of the amp's socket, without worrying about putting additional strain on the PCB; some EL34s can still be a little tough to put into the sockets savers though, but this is much easier outside of the amplifier.
  
 Anyway, they are gold plated with ceramic bases and I have not heard any noticeable sonic differences while using them.  I definitely recommend them to save your sockets from tubes with nasty pins.
  
 Also, let us know how the new tubes turn out.  If I remember correctly, I believe I actually preferred the orange globes in my system to the bugle boys with the GEs, but every system is different.


----------



## fccn75

jk-47 said:


> Effusion,
> 
> What kind of socket savers do you have? Any pics of your amp with them?
> 
> I ended up with GE 6L6GC's and Amperex orange Globe's. I'll be home in a little over a week to try them out, I can't wait!


 
 Wow, I was thinking of doing the same 
	

	
	
		
		

		
		
	


	




  Just curious, which vendor did you purchase those tubes from?


----------



## fccn75

effusion said:


> fccn75,
> 
> You're very welcome, I hope the impressions of bixby and I may help you either now or down the road.
> 
> ...


 
 Was away again on business trip so had to wait until now to reply.  Unfortunately, those Genalex KT-88 I have are the Russian made ones and not the NOS English brand.  Just looking at the post from JK-47, I am contemplating on getting that combination but the 12AU7's raise curiosities. I
  
 I have a pair of Gold Lion ECC82/B749 which didn't really do much while a pair of JAN 5963 tightened the mids more so than the RCA but slightly loss some of the fullness.  Also have a pair of Tungsol 6189 which to my ears have a slight elevated mid treble.  I will try to find some Tungsol "Black Glass" and Amperex to see if it's enough to satisfy my ears on the lower registers.  And if I am really lucky, get a pair of those GE 6L6GC like JK-47!  Will report back once those are in my possession.  
  
 Thanks


----------



## Effusion

fccn75,
  
 Glad you are back home and I hope the trip went well.
  
 Yes, I believe a change of power tubes should help you get more out of the HD800, at least what you are looking for.  I've found that more often than not, bigger changes in the sound signature are achieved by different types of power tubes compared to the signal/input tubes, however this, as always, depends on which tubes and your system in general.
  
 The NOS GE 6L6GC are nice because they offer pretty good sound for a very reasonable price compared to the typical cost of high quality variants and in my system, they definitely gave a boast to the low end.  I've found that while NOS EL34s provide some really nice mid-range, they can sometimes be a little light in the bottom end, with the Mullards giving a bit more weight, but not as much as the other variants.  I've come to really enjoy the KT-66 and KT-88 types, but unfortunately NOS and even the Psvane are not cheap.
  
 I haven't really mentioned the 807 tubes very much in the past, but they have also given me a great amount of lower-end weight and punch and are also very reasonable in price.  However, you have to get an adapter plug with a top pin cap, as on of the pins is actually on top of the tube.  RCA made most of them here in the states and they are pretty easy to find.  The militarized short bottle 5993 have the better resolution, but a bit less sound-stage and are a little harder to find.  If the GEs turn out to not be your flavor, than these would probably be my next best recommendation of the types to try without breaking the bank; just make sure you get the right adapters (let me know if you have questions).
  
 As far as 12au7s, I have tried the JAN 5963 and I agree, they do tighten up a bit and have a little more resolution, but lose a little depth and bloom.  I've found that typically the militarized versions offer a cleaner and more upfront presentation, in addition to being generally better made as the stringency and minimum specifications of the military are higher.
  
 The Tungsol black glass are nice, but are also a little rare and may be hard to find; plus, because of the rarity, they can go for higher prices.  If I remember correctly, the black plate versions gave me the low end boast, while the gray plate versions were a little more shy in the bottom.  It is hard to tell from pictures though, since the coating on the glass covers much of the visibility of the plates and it is best to ask the seller if the plate color is not listed in the description.
  
 The Amperex are typically a high resolution tube with great mid-range, but the bugle boys might give more in the top end than the bottom.  If you are looking a Amperex, also look at the Brimars or the Mullards, as they have tended to be better in the lows, but they are laid-back and are not as forward as the Amperex.
  
 Thinking about what you are looking for a little more, I actually think the CBS 5814W may actually give you the best out of the other recommendations.  They have a very full sound and great bass, with no extreme or extra sparkle up top.  However, they are not common as not many were made compared to the other types.  If you can find a price on them, they should actually be a little cheaper than say the Amperex Bugle Boys and even the Tungsol black glass, just because they are less known.
  
 The best option for now might be to try to get a pair of GE 6L6GCs and see if they help at all before trying different 12au7s.  If you're not careful, this hobby can really take a bite out of your wallet, as you may find yourself just wanting to try anything and everything, like me.  However, if you bargain shop and are okay with selling off ones you don't care for, than it can truly become a great quest for audio bliss that is both fun and very engaging, with a better investment to enjoyment ratio; just try to remember that sometimes it is best to let a tube settle a bit and burn-in before being completely dismissive as some have really surprised me after a few days or the second time around.


----------



## vkung

Review from Wall of Sound  By Tim Smith
 Another wonderful review for TU-8200DX
Elekit TU-8200-DX integrated amplifier/headphone amplifier kit | Wall Of Sound


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## vkung

*Elekit TU-8200-DX integrated amplifier/headphone amplifier kit | Wall Of Sound
 Wall Of Sound | Recordings, Concerts and Audiophile Stereo Reviews
 Reviewer : Tim Smith*

*Elekit TU-8200-DX integrated amplifier/headphone amplifier kit
 Posted on 2015/01/28 by Tim Smith in Uncategorized // 0 Comments*
*Elekit TU-8200DX Integrated Amplifier/Headphone Amplifier Kit $725 USD. Review by Tim Smith*
*The Elekit TU-8200DX stereo amplifier kit is a gift to the audiophile community. I am unaware of a smoother, quieter, more musical, more pleasing integrated amplifier/headphone amplifier in this price range. The price to quality ratio is outstanding.*
  
 As I hooked up a pair of lovely Unity Audio "Inner Soul" speakers to the the Elekit TU-8200DX integrated amplifier the sound was rich, warm, full and smooth as silk. Crossover-less Fostex drivers can sometimes shout but not paired with the Elekit. When single driver speakers are done right, you really can see into the heart and soul of the music. The Unity speakers have a name worthy of their character. Highs soar without becoming shrill. Room ambience is recovered and instruments seem to have air surrounding them. Johnny Hartman's voice is startlingly realistic. The Elekit is perfectly matched with the Unity Audio speakers. In fact the Elekit worked with each and every speaker–and there were five–I used. Harbeth Compact 7s? Check. SVS Prime, Tekton M-Lore, Mordaunt Short Carnival 2? You bet, no sweat. The Elekit also paired perfectly with Beyerdynamic DT-880 and HiFiMan HE-400 headphones.
 The TU-8200-DX is made of aluminum with a silver-matte finish. This is a kit amp, but when it's assembled you would never know it, for there is nothing DIY about the fit, finish, or sound. In less than ten minutes, most of us could come up with a catchy name suggesting silvery smoothness. Alas, in keeping with the general trend in audio, we have letters and numbers–TU-8200-DX. This wonderful amp deserves a better name. Now that I have dismounted that hobby horse, let the praise flow, like a mountain stream?.
 IMG_2574
 Elekit TU-8200-DX in the middle, beneath the big Coincident Turbo 845 SE integrated amplifier.
 VK Music of Vancouver imports and distributes Elekit, Triode Labs and other Japanese audio brands. The VK stands for Mr. Victor Kung. There is no 35-hour week chez Victor; a full-time accountant by day, VK Music is his moonlight gig. Victor is a mainstay on the audio show circuit. The amp under review was demoed in Montreal and Toronto in 2014 and soon I must (regrettably) send it back so Victor can take it to the Chicago audio show. VK Music's product line is stuffed full of eye-popping bargains. This is one lean low mark-up machine.
 Elekit has gained a strong following in North America and Europe largely on the basis of very favorable reviews in major online publications and due to positive chatter in online forums like Head-Fi.org - Headphone forums and reviews for audiophiles. Elekit has been selling science project kits to Japanese high school students for forty years; the audio wing has been in business for almost 30 years. Mr. Hidemi Iguchi and Mr. Yo****sugu Fujita are, respectively, the president and chief engineers. If you'd like to read more about Elekit's history, and if you are curious about the process of building an Elekit, I suggest looking at the two detailed reviews of this amp and its predecessor by David Kan of 6moons: sponsor showcase & access portal.
 TU-8200 parts
 Elekit's mission is to provide first-class audio kits at real-world prices. Some Elekits are partially assembled, involving minimal work on your part. You pay for the high-quality parts, the design and a small mark-up. This business model might save you a sum of money equal to the price tag you pay. In the case of the TU-8200DX, you are paying $725 for a product that might retail in a store for $1,300 to $1,500. Most people's time is not that valuable so this is a very attractive proposition. And I haven't begun to mention the joys of building something with one's own hands.
 I was given the option of reviewing a pre-assembled amp and I accepted. I have built a very DIY-looking Bottlehead Crack headphone amp. It took me 25 hours to find my way, which is far above the average time for most customers. Comparing the parts list and layout of the Elekit and the Bottlehead, I would guess that the Elekit would be a bit easier to build. David Kan required 15 hours to assemble his unit. Having said that, with 55 resistors to solder, not to mention the capacitors and the transformer leads, this project will require quite a bit of elbow grease, dexterity and patience. But the chassis seems large and unlike the Bottlehead, the Elekit doesn't seem to have a particularly cramped layout. On top of this, many people find soldering a PCB board easier than point-to-point wiring using numerous terminal strips and the like.
 The TU-8200DX is shipped with 6L6 output tubes but the amp is auto-biased and you can swap EL34, KT66, KT77, KT88, 6550 and KT90—there are no switches to change. Just turn off the amp, let it cool down, and unplug before you roll tubes. The input tubes are 12AU7, allowing for numerous affordable tube-rolling options. If you are willing to unscrew the case, you can adjust a couple of small jumpers and switch between ultralinear, pentode and triode modes. The TU-8200DX's headphone out uses three resistors to connect to the output transformers.
 Under the hood you'll find the stock, high-quality Japanese R-core transformer and output transformers, the heart of the design. On the back of the amplifier you'll find two RCA inputs. There is also an impedance switch to match the amp to your speakers. On the front, you'll find the ¼"headphone jack. The TU-8200DX can accommodate an optional and inexpensive Elekit-supplied DAC.
 Using the stock 6L6 tubes, the Elekit will output up to 8.2 watts in ultralinear and pentode mode and roughly half that in triode mode. This is a versatile amp but unless you want to undo screws and remove the cover to switch between triode, pentode and ultralinear modes, you'll have to drill an access hole and risk defacing your top plate. David Kan succeeded but unless you are adept with your drill, don't try this at home.
 The casework is sturdy and attractive in a minimalist way. The TU-8200DX weighs in at 6.6 kg or about 15 pounds. My review unit came upgraded with a long list of Amtrans carbon resistors, five Nichicon polymer aluminum electrolytic capacitors and $100 worth of Amtrans AMCY oil coupling capacitors. My upgraded amp would cost you close to $900.
 The $725 to $900 Elekit is situated at an un-crowded price point. Inexpensive Chinese-made single-ended tube amps with headphone sections abound in the $300 to $500 price range, but the Elekit falls outside this super-budget category. The Elekit's provenance is also clear—from Japan to Vancouver to your house, there's no gray zone of rebranded products. You're not going to get fake WIMAs or capacitor meltdowns with this design. Should you need a repair it should be quicker and less expensive than the seemingly bargain-priced fare hailing from Shenzen. This is an amp for the long haul.
 I think you get what you pay for; the Elekit is quieter and smoother than everything I have heard in the lower price bracket (Yaqin, Audioromy, Musical Paradise, vintage American amps using 6V6 and 6L6). As a loudspeaker amplifier I think the Elekit is pretty close to the similarly priced Decware gear I have heard, but it's substantially warmer and smoother, a bit thicker sounding, and not as open and fast. It is denser with richer tonal colors. The 6L6 tube can provide the deepest timbres with strings and woodwinds and the Elekit taps into all that glorious tube's potential. The Elekit falls squarely in the traditional tube sound range without being slow or muddy. Paired with SVS Prime loudspeakers, the Elekit is more than equal to the task of conveying the psychedelic, bouncy beat of "Up From the Skies" (Jimi Hendrix, Axis: Bold as Love) in my small/medium listening room. I did, however, have to turn the amp, literally, to eleven. Headbangers won't pair this amp with the speakers mentioned above but headbangers won't be interested in this amp in the first place.
 IMG_2577
 Elekit in the middle, above the Jimi Hendrix LP. Hooked up to SVS Prime loudspeakers.
 The Elekit comes close to my Coincident Dynamo SE in its quietness and its ability to capture the warm tone of a jazz guitar. It seems to have a bit less pluck, less bite, but it can bloom with the best of them. John Coltrane's tenor sax on "Wise One" positively blooms with the Elekit, as it does with my Coincident. Paired with Unity Audio "Inner Soul" speakers, Elvin Jones' cymbal strikes during the first thirty seconds of "My Little Brown Book" are as full, dimensional, and as lifelike as I have ever heard them, even with systems costing ten times more.
 MI0000534394
 If you listen to nothing but simple acoustic music in a small room, and if you don't need a remote control, the Elekit, like the Coincident, could be a final destination product. The fifteen-pound Elekit cannot quite match the speed and drive of the $1,299 twenty-two pound Coincident but it's pretty darn close and there's no question the Elekit has a smoother, more fluid headphone section, with no hum at all.
 IMG_2276
 When lights were low, I compared the Elekit with the Dynamo. The Dynamo won, but not by much.
 The Elekit's distinguishing features are its smooth-as-silk musicality and its lack of noise. Through low and high impedance headphones, there is no hiss. The Elekit is a jazz trio's dream come true. With sensitive 95dB loudspeakers it's very quiet–not solid state quiet, but with far less noise than a typical tube amplifier in this price range. Even in the quietest moments of piano or guitar sonatas, the background is as black as night. This allows you to see all the detail, but remember, there's no etch or brightness. It's perfect! You can revel in subtle details like fingernail scrapes on metal strings or the long decay of a struck piano key, if that's your thing. But the Elekit is no cold clinical tool. The Elekit seems to strike a perfect balance between detail retrieval, noiselessness, and musicality. The one area in which the Elekit clearly loses out to my Coincident is in the bass grunt–there is ample bass (for me, but YMMV) but this amp is obviously not a perfect match for complex orchestral music or hard rock. But it's good enough.
 So, is this a headphone amp first and foremost, and a speaker amplifier as a second thought? It's hard to say but I think Elekit seeks to satisfy both markets. Not quite five minutes after listening to various Woo Audio amps at the 2014 Montreal and Toronto audio shows, I listened to the Elekit. It sounded just as good—big, powerful, quiet and possibly a bit smoother. The Woo line generally has firmer bass, but ever so slightly. With its ability to drive loudspeakers as well as headphones, the Elekit is undoubtedly a better bargain than anything in Woo's fine line of products. Elekit's transformers are made in Japan to very high standards. There is zero mechanical hum. The Woo and Decware gear I have owned and reviewed has all hummed, just a little bit, but enough that I noticed it during piano sonatas.
 IMG_2289
 Wolfert Brederode's clarinet is ravishing and the Elekit captures that trademark ECM reverberant sound.
 With NOS Mullard M8136 (12au7), Tube Amp Doctor 6L6 WGC-STR, NOS RCA 6L6WGB, and half a dozen EL34s on my shelf, I put the stock tubes away, figuring I'd start with the best possible sound and then see how big the change was as I downgraded the tubes to normal fare. In fact, tube snob that I am, I never bothered to use the stock Electro Harmonix tubes. I recently dropped an exquisite Psvane KT88 black bottle tube.That was an expensive mistake, and it meant I was unable to try KT88s, but I still had over half a dozen power tubes to roll. The Elekit responded well to tube rolling, showing off each particular tube's strengths. I spent most of my time listening to 6L6 in pentode mode.
 To evaluate the headphone section, I started with my HiFiMan HE-400s and proceeded to my Beyerdynamic DT880s hooked up to a Marantz SA-8003 CD/SACD player. The Bennie Maupin Ensemble, Penumbra CD was an eye-opener. Bass clarinet was probably as deep as it has ever been through cans, with bloom up top and rattle down below. With the volume knob at 9 o'clock, the Elekit was in complete control of my Beyers. There was a great soundstage and no audible noise floor. The sound was smooth and clean at both frequency extremes. The beat was fluid, easy, relaxed. Charles Lloyd's saxophone on his CD "Lift Every Voice" was reedy, breathy, and full. Immense, in fact.
 Unknown Unknown-1Unknown-2
 The Elekit is no speed demon or PRaT machine. It seems more balanced, less concerned to startle you with transient snaps than to present the whole picture. It's more laid back, never upfront or etchy. The soundstage is very large. This is world-class. At just nine o'clock the volume is loud. It is a perfect pairing. Wolfert Brederode's clarinet is as smooth and sweet as honey. Stunning!
 IMG_2233
 HiFiMan HE-400s paired well with the Elekit, fed by a Maverick DAC.
 With most simple jazz and classical music, the Elekit had no trouble getting my Harbeth Compact 7s to loud volumes in my small to mid-sized listening room, and the amp coaxed all the sweet tone from Joe Pass' solo guitar I could hope for, but with more demanding orchestral music the Elekit ran out of steam when I turned the dial to 12 and bass was somewhat too smooth—not flabby or wobbly but simply not dry enough for my liking no matter the volume. All that changed with my Tekton M-Lores which at 95dB and 8 Ohms are more sensitive and a better match for this amplifier. With the Tektons, bass was ‘good enough', something I could live with. I put the Elekit to the reggae test and it did surprisingly well, keeping up with Peter Tosh on "Pick Myself Up." If you are looking to put together a sub $2,500 system, the Elekit seems like an obvious choice paired with some inexpensive high-sensitivity speakers like those of Tekton Design. Buy this amp, get off the mad merry go round, and don't look back.
 Unknown-3Unknown-4Unknown-5
 The Elekit can almost render terrible music listenable. It quiets down the shrill voice of Kevin DuBrow.
 On the opening bass line to "Closer to the Heart," there's that clear Rickenbacker sound of Geddy Lee's early years, before he switched guitars. In triode mode using TAD 6L6s, bass is a bit muddy. Pentode firms things up a bit, but bass on Rush's "Best I Can" is not the best I can get from a single-ended tube amp. My Coincident Dynamo SE is twice as good in this regard. In the end, I can see no other weakness to this wonderful amp. You can do better–the Coincident is proof of that–but you'll need another $500 to get there.
 Hooked up once again to the Unity Audio "Inner Soul" speakers I have on review for WallofSound.ca, the Elekit was, once again, smooth and quiet. That's a good thing considering these crossover-less, sensitive speakers will reveal any flaw in the recording. The Elekit and Unity Audio pairing was perfect—detail and speed from the Unity was tempered by the smoothness of the Elekit. The sound was utterly open and transparent, three-dimensional. Spinning a pristine, unopened! LP (Ben Webster's Soulville) for the very first time, I said to myself: that trademark raspy tenor is right here in the room. There was recording studio ambience and air, ample detail, and a rich, smooth sound. Divine! This little amp is a holographic imaging machine. It excels in creating a realistic, three-dimensional soundstage.
 The Elekit TU-8200-DX is a perfect solution for those seeking a world-class sub-$1,000 headphone amplifier, or a sub-$1,000 single ended loudspeaker amplifier–or both! If Victor Kung did not need this demo amp to take to the Chicago show, I certainly would have bought it. As much as I love my $500 (including shipping, exchange rate) Musical Paradise MP-301 mk3, the Elekit is on another level. True, it costs more, but to me it's worth it. This is the type of amplifier one can listen to all day long with no fatigue whatsoever. This is a gem of an amplifier. Highly recommended.


----------



## JK-47

effusion said:


> While I don't have any pics of my amp with them readily available, below are the exact ones I use:
> 
> http://www.ebay.com/itm/1pc-Octal-Gold-plated-tube-saver-adapter-for-EL34-GZ34-KT88-6V6-6P3P-5Z3P-6SN7GT-/191109289479?hash=item2c7f005607
> 
> ...


 
  
 Those socket savers look nice!!! Do you have a set of savers for the 12AU7's? That seller only looks like he has 12AU7 socket adpaters that allow different tubes...


----------



## vkung

This is the link  RCA 607 to 6L6GC...
 http://www.ebay.ca/itm/6L6-Octal-8-PIn-Bottom-To-807-5-Pin-Top-Tube-Socket-Conversion-Adapter-for-Amp-/310833694436?pt=LH_DefaultDomain_0&hash=item485f21c6e4


----------



## catcherfly

I built the TU-8200 last week with the 6L6GC + 12AU7 tubes, upgraded resistors + capacitors.  I had the enclosure powder coated matte black. This was a first time build for me (and first single driver tube amp) and it took me the better part of a weekend. I could not be happier! Victor immediately answered a number of my questions while putting it together (all of which was very satisfying) and I absolutely love the sound! I'm currently running in Ultra Linear mode, listening through HiFi Man HE-400i and Audio Nirvana Super 8 Alnico full range drivers in custom built mini monitor cabinets. I have a Audio-GD NFB-28 Preamp/DAC/Balanced Headphone Amp but I much prefer the headphone section of the TU-8200. I look forward to trying different tubes at some point.


----------



## Effusion

jk-47 said:


> Those socket savers look nice!!! Do you have a set of savers for the 12AU7's? That seller only looks like he has 12AU7 socket adpaters that allow different tubes...


 
  
 They're really nice, hand built and sturdy, not as cheap as some of the basic Chinese Bakelite versions that are abundant, but the ceramic keeps them cool and the gold/copper seems to make a great connection.  However, as you noted, the seller does not offer the same in the 12au7 or 9 pin version.
  
 There are quite a few pretty basic Bakelite socket savers out there and many can be had for very cheap; however, often they are made poorly with inferior pins.  For hi-fidelity audio, there are better, but more expensive options, as these cheaply made savers are really only good for use with tube testers, etc.
  
 A few to look into are the NOVIB savers (by TubeMonger) with NOS bases/pins.  They claim to reduce microphonics while providing a better connection as well.
  
 12au7 (just sold out 
	

	
	
		
		

		
			





):
http://www.ebay.com/itm/NOVIB-Socket-Saver-with-1960s-British-McMurdo-Phenolic-Socket-Vib-Reduct-Base-/161565750831?pt=LH_DefaultDomain_0&hash=item259e11b62f
  
 EL34/KT/6L6GC:
http://www.ebay.com/itm/OCTAL-SOCKET-SAVER-NOVIB-NOS-GE-USA-OMRON-JAPAN-Vib-Red-Base-NOT-Made-in-China-/160879655126?pt=LH_DefaultDomain_0&hash=item25752cb8d6


----------



## Effusion

catcherfly said:


> I built the TU-8200 last week with the 6L6GC + 12AU7 tubes, upgraded resistors + capacitors.  I had the enclosure powder coated matte black. This was a first time build for me (and first single driver tube amp) and it took me the better part of a weekend. I could not be happier! Victor immediately answered a number of my questions while putting it together (all of which was very satisfying) and I absolutely love the sound! I'm currently running in Ultra Linear mode, listening through HiFi Man HE-400i and Audio Nirvana Super 8 Alnico full range drivers in custom built mini monitor cabinets. I have a Audio-GD NFB-28 Preamp/DAC/Balanced Headphone Amp but I much prefer the headphone section of the TU-8200. I look forward to trying different tubes at some point.


 
  
 Congrats on the build catcherfly!  That black matte paint job looks just great!!  Most of my components are black, so I've actually considered painting my Elekit black as well; nice to see that it looks great in black!
  
 Give the amp some burn-in time and let us know how things progress!


----------



## JK-47

Catcherfly,
  
 Sweet looking build!!! Nice to see it in another perspective.


----------



## mhamel

Time to join the TU-8200 club.  I finished up my TU-8200DX build last week.
  
 I went with all of the upgrade options Victor offers, including Amtrans oil caps for coupling. I also replaced the plastic 9-pin tube sockets with ceramic gold pin sockets, and the included volume pot with an Alps RK27 Blue Velvet (the section of the board where the volume pot mounts is designed to break away to accommodate the RK27 - one tip - if you go with the Amtrans oil coupling caps, the gold plated leads that get clipped off when the caps are soldered in make good bridge leads from the main board to the volume pot board if going with the larger pot)
  
 I'll reserve any in depth comments on the sound until it's had time to fully break in, but my initial impressions are very good.  I'm primarily using it as a headphone amp to drive my LCD-X, running in Triode mode.
  
 One minor annoyance - I do wish there was a better system to switch modes other than having to remove the entire top cover and change jumpers. I understand wanting to prevent someone from switching while the amp is running, but even if it was a switch under a small access panel that required a couple of screws to be removed it would be more convenient.
  
 Otherwise, the kit itself is top-notch. Quality parts, nice construction (if a bit plain) on the casework, well-packaged. This is far from my first kit, DIY or electronics project but it was one of the most fun kits I've built. I was almost sorry that it was finished.
  
 As for difficulty, I don't know if I'd recommend it to someone that has never tackled any DIY or kits before, mainly due to some of the soldering required and the voltages involved, but for anyone that has a good handle on soldering basics and has some previous kit or DIY experience, it shouldn't be a difficult build. It took me 4 nights of a few hours a night, partially because I was waiting for the RK27 to come in and partially because I've got a habit of measuring/matching every part before I install it.
  
 Communication with Victor before, during and after the sale was also great. He's patient with questions, responds quickly and has been a pleasure to do business with.
  
 Meanwhile, as it burns in, I'm enjoying it and will post more impressions of the sound later.
  
 It's also given me a chance to dig through my tubes plus pick up a few new pairs to roll, which I'm looking forward to.
  
 Pre Tubes:

New:
Gold Lion B749
EH 12BH7

NOS:
Several different RCA and Sylvania 12BH7/12BH7A
1950s Sylvania 12AU7a
1960s RCA "Cleartop" 12AU7a
1952 Raytheon JAN-CRP 5814
1962 RCA JRC 5814A
1956 RCA 5963

  
 Power Tubes:

New:
Gold Lion KT88
Gold Lion KT66
Tung Sol Tall Bottle 6L6G (6L6GC spec)
EH KT88EH
EH 6550EH
Mullard EL34

NOS:
1960 RCA 6L6GC

  
  
    -Mike


----------



## Effusion

Hi mhamel,
  
 Congrats on the build!  The upgraded parts you used are very interesting, especially the ceramic/gold sockets and the Alps RK27 Blue Velvet, to me; very nice additions!
  
 You also already have some really nice tubes to try out; I assume the NOS RCA 6L6GCs are the black plate version, which I've found to be a very clean/articulate tube with the Elekit, while the GEs have tended to be a little more lush, but with less overall control over the sound and a bit more laid-back.  Those NOS military 12au7 equivalents are also very nice and should provide you with several options to pair with your LCD-Xs.
  
 Once you're able to get some hours on the amp it would be interesting to me, as well as probably a few others following the thread as well, to get your impressions of how some of your new stock tubes perform, as most of what I have is old stock.  Any general impressions of how they do would prove useful to us all; especially since they are easier to find, in addition to being, generally, a bit easier on one's wallet.
  
 Keep us tuned and welcome to the club!


----------



## mhamel

effusion said:


> Hi mhamel,
> 
> Congrats on the build!  The upgraded parts you used are very interesting, especially the ceramic/gold sockets and the Alps RK27 Blue Velvet, to me; very nice additions!
> 
> ...


 
  
  
 Effusion,
  
 Yes, the RCAs are the black plate versions.  I haven't run them in the amp yet, but I've heard good things about them.  At the moment I'm running a pair of early Sylviania black oval plate 12BH7s along with the reissue Gold Lion KT88s. I've heard such mixed/extreme opinions on the reissue tubes with some people saying they're every bit as good as NOS and others swearing they're so horrible they'll make your ears bleed.  Since all of the reissue tubes combined are less costly than one pair of actual NOS Gold Lions, I figured it was worth listening to them myself.
  
 I've used the RK27 in several other builds and when I saw the board was designed to accept it I didn't even bother trying the stock pot.
  
    -Mike


----------



## JK-47

mhamel,

Congrats on the build! 

What is the advantage of the RK27 blue velvet volume pot?


----------



## mhamel

jk-47 said:


> mhamel,
> 
> Congrats on the build!
> 
> What is the advantage of the RK27 blue velvet volume pot?


 
  
 JK-47,
  
 Thanks!  The main advantage of the RK27 blue velvet is tighter channel balance.
  
     -Mike


----------



## vkung

my preference  is TKD 2CP601S ...


----------



## JK-47

Just got home and picked up my tubes this morning...
  
 First I warmed up my amp and listened to 7 FLAC tracks that I planned on using for reference. I powered everything down, waited 15 min, and switched out the stock 12AU7's for the Amperex Orange Globe's. I let the amp warm up for 20 min and fired her up. WOW! Immediately I noticed that the sound stage opened up nicely compared to stock. The low end was cleaned up and tighter, the mids were very detailed (I could clearly hear back ground vocals, that were muddy before), and the hi end had a nice sparkle without sounding harsh. I was impressed to say the least.
  
 Next I followed the same power down/up/warm-up procedure as before, and the GE 6L6GC's were in their new home. I'm on the 4th reference track as I type this sentence. I'm blown away!!! Everything is tighter and richer, it's hard to describe... The low end is still there, but way more precise and controlled, the mids sound smooth and effortless, the top end is really accurate without overpowering anything else. The sound is wonderfully balanced and has really come to life...
  
 I'm in audio heaven right now. I can really crank up the music without losing any detail, simply amazing...
  
 I cleaned all the tube pins with a brass brush and put a little De-Oxit on them before the install. De-Oxit did make a noticeable difference with my modded Fostex T50RP's and their stock cable, so I figured why not.
  
 Sorry, gotta go... too much music to re-discover!!!


----------



## Effusion

JK-47,
  
 Great to hear you're liking the NOS Amperex and GE, they are great NOS tubes for a very reasonable price!
  
 I never really did try the stock China stamped 12au7s, except for testing, and I listened to the stock EH 6L6GCs for about a half hour or so, but I agree, much better sound can be had by changing them both out.  If I remember correctly, the stock EH 6L6GCs were very laid back and quite muddy, but with a good amount of sound-stage and presence, just less detail and a bit of a veil.  However, the NOS GE 6L6GCs are really nice tubes for the money and can really bring the music to life with great impact, but also in a smooth and silky way.
  
 Congrats on the new tubes and keep us up to date on your impressions!


----------



## catcherfly

jk-47 said:


> Just got home and picked up my tubes this morning...
> 
> First I warmed up my amp and listened to 7 FLAC tracks that I planned on using for reference. I powered everything down, waited 15 min, and switched out the stock 12AU7's for the Amperex Orange Globe's. I let the amp warm up for 20 min and fired her up. WOW! Immediately I noticed that the sound stage opened up nicely compared to stock. The low end was cleaned up and tighter, the mids were very detailed (I could clearly hear back ground vocals, that were muddy before), and the hi end had a nice sparkle without sounding harsh. I was impressed to say the least.
> 
> ...


 

 Your take on your upgrade tubes is irresistible. Can you tell me where you got them?


----------



## JK-47

Catcherfly,

I scored both sets on eBay, and I have another set of GE 6L6GC's on the way as back up.

Effusion,

You weren't missing anything with the stock 12AU7's. The change to the Amperex input tubes made more of a difference than the change to the GE power tubes. The GE's are slightly different sizes, one being a tiny bit shorter and wider, but after reading up on different size bottles. The consensus seems to be as long as they're matched its not a big deal.


----------



## Effusion

Good to know about the stock 12au7s... I was lucky enough to already have a few NOS pairs prior to plugging the amp in the first time, so I just didn't bother.
  
 Not too sure about the tall bottle GE, I believe most of what I have would be considered short bottles.  It is best to try to get matched pairs though, not only in conductance, but also in make and dates when ever possible.  Small changes in the manufacturing can create slight differences in sound signature between tubes and thus, between the channels; however if they are close enough, the ears will probably compensate and the perception would probably be that they are very similar.  For resale though, in the case you didn't like them or in the future you decide to part with them, it is best to have exact matches as they'll demand a higher price.
  
 I found that while variants within the same tube type had more subtle differences, changes between types yielded bigger more noticeable changes.  If you're able to score a pair of EL34s or any of the KT series, you may find that the change, when compared to the 6L6GC, in you system offers a bigger change than between 6L6GC variants.  I really like the KT-66 and even the McIntosh KT88 are nice as an every day tube, but they are not necessarily cheap.  The SED Winged "C" EL34s are cheaper and not too bad sounding, not as good as the Mullards or Amperex, but generally much cheaper.  I've also liked some of the Groove Tubes or Mesa Boogie Tubes that are new stock, but considered better quality than most new stock; they are generally used with guitar amps, but I've found them to offer a nice solid sound, if not a little less tubey than more expensive NOS.
  
 Ahh, the world of tube-rolling, so many options, so little cash...


----------



## catcherfly

jk-47 said:


> Catcherfly,
> 
> I scored both sets on eBay, and I have another set of GE 6L6GC's on the way as back up.
> 
> ...


 

 Thanks JK-47!


----------



## JK-47

Effusion,
  
 Well, I decided to return the GE 6L6GC's to the seller... He was a little sour, but it appears that one of the tubes is actually a Groove Tube, slight traces of  Orange/Red paint (Groove Tube logo) and the font for "6L6GC made in the USA" were different between the 2 tubes (the suspect tube's font looked thicker, like a Groove Tube reissue). I'm not accusing him of rubbing the logo off, but I feel slightly misled. He says he will measure them when they get to him, but I said that's not the point. They were advertised as being 1959 GE tubes... Ah, the wonderful world of ebay.
  
 The switch back to the Electro Harmonix 6L6's was noticeable. I definitely noticed the loss of detail and punch in the mids and lows.


----------



## Effusion

So sorry to hear about that... seems everyone is only trying to make a buck nowadays on the Internet and that you can't really trust everyone anymore.  At least he is accepting the return, he almost has to as the description of the items was not correct, which is a direct violation with eBay, so not much he can do and if he resists, you can just start a claim.  Over the years, eBay has been much tougher on sellers and even negative or below 5 star service can really hurt them in the long-run; one thing to watch out for is if the seller has changed names recently, as it clears their rating, but this is usually because it got too bad for the volume they sell.
  
 Sometimes it's hard to tell with the older GE's as the labels tend to rub-off easily, same with the EL34s, and they sometimes didn't print the bases on the older batches.  One thing though, on pretty much all GE tubes (regardless of type), they will have a "dot pattern" near the GE/date label, even on re-brands.  Not really sure what the pattern means, as it is a little strange, but it is one way to distinguish between what is GE and what is not.
  
 I haven't tried the Groove Tube 6L6GC, but the other types of Groove Tubes I have tried weren't horrible for new stock, but definitely not the best.  You did the right thing by returning them and I hope the backup spares you ordered will work out for you better.
  
 Keep us tuned!


----------



## JK-47

Effusion,
  
 I had already gave him positive feedback before I really looked closely at the tubes ( I was more worried about them being broken). When I tried to contact him, I used the listing and chose item not as described as reason I wanted to return them. Apparently it opened a case against him (I didn't know ebay worked like that), I didn't mean to, I merely wanted to contact him. He took it to heart and said all kinds of things, like I personally attacked him. I explained several times that I just wanted a refund and that was it. He said I called him a liar, which I didn't, and explained I wasn't going to get in a pissing contest with him. I live 7 hrs from him and was almost considering paying him a visit, just to straighten things out, he was really starting to act childish. Oh well, I hope cooler heads will prevail and he keeps our agreement, and pays me back within 24hrs of receiving the tubes.
  
 Geez, the stock EH 6L6 tubes are not even in the same league as the GE's ( lack of detail to say the least) 
  
 The back ups should be here tomorrow... now I need to find backups for the backups, lol
  
 Effusion, did you ever start the thread regarding your tube journey?


----------



## Effusion

Crazy, sorry that all happened.  I agree, it's hard to just contact the seller after the sale, seems like eBay wants everyone to start a case; understandably so that the buyers are protected and they can track, but I've also had issues with this when I just wanted to ask a simple question after a sale, without having to go to all that trouble.  If the seller sells a lot of tubes, than they really should have known that these were only matched in conductance and not the same tube type/manufacturer.  The description of a potential sale is everything, so as a seller you really need to be as thorough as possible in your examination; mistakes do happen and no one is perfect, but the biggest mistake sometimes is just being in denial of the initial mistake, regardless of taking it out on others, especially when the whole reason for selling a matched pair is that they are actually truly matched... anyone could find two of the same type of tubes that have similar tests results, but are of different makes/manufacturers, and call them matched, but this is not what the term "matched" implies and no one in their right mind wants to pay a higher price for a pair of matched tubes that are in fact very different from each other.
  
 Anyway, I hope everything gets sorted out.  No worries and no need to feel bad, it's not the buyers responsibility if the listing was described wrong; if the seller had stated that the sale was for one GE and one Groove Tube, than it would have been a buyer mistake if this is not what was expected, but that wasn't the case.  Also, sometimes it's hard to wait a little before leaving feedback, especially if the seller starts to inquire about the feedback soon after the sale, but sometimes it is best to wait just a few extra days, as this is ultimately the buyer's chip if something goes awry.  I guess one way to look at it is that it may have been a good learning experience for both parties in the end, sort of a silver lining to the headache endured, in order to help avoid the same issue in the future.
  
 Unfortunately, I haven't been able to really document all my experiences with tube-rolling the Elekit yet; I've tried so many types and haven't really had the time lately to sit down and focus.  Seems the more I try, the more I want to try, then the more I buy, and suddenly the amount/variety starts to snowball, which can be a little overbearing.  Really the only experiences I've shared so far have been in this thread; I just hope that with all the various types I've tried over the past year or so, I haven't mixed things up badly or given any wrong impressions.  I'll admit that sometimes I've commented on a tube that I haven't really listened to in a few months, however most have left me with enough of an impression that I feel confident that I'm not totally misleading anyone, at least not intentionally.  As always though, the best thing to do is to take my suggestions as just that, a suggestion from my system/ears, and let your own ears make the final decision/verdict for you, in your system.  Many factors can influence the sound of a tube, as every system is different, not even to mention that every headphone is also different.
  
 If you ever have any questions or concerns regarding a type of tube up for sale before you purchase, let me know and I'll try to help as much as I can; I really don't mind.


----------



## JK-47

effusion said:


> Crazy, sorry that all happened.  I agree, it's hard to just contact the seller after the sale, seems like eBay wants everyone to start a case; understandably so that the buyers are protected and they can track, but I've also had issues with this when I just wanted to ask a simple question after a sale, without having to go to all that trouble.  If the seller sells a lot of tubes, than they really should have known that these were only matched in conductance and not the same tube type/manufacturer.  The description of a potential sale is everything, so as a seller you really need to be as thorough as possible in your examination; mistakes do happen and no one is perfect, but the biggest mistake sometimes is just being in denial of the initial mistake, regardless of taking it out on others, especially when the whole reason for selling a matched pair is that they are actually truly matched... anyone could find two of the same type of tubes that have similar tests results, but are of different makes/manufacturers, and call them matched, but this is not what the term "matched" implies and no one in their right mind wants to pay a higher price for a pair of matched tubes that are in fact very different from each other.
> 
> Anyway, I hope everything gets sorted out.  No worries and no need to feel bad, it's not the buyers responsibility if the listing was described wrong; if the seller had stated that the sale was for one GE and one Groove Tube, than it would have been a buyer mistake if this is not what was expected, but that wasn't the case.  Also, sometimes it's hard to wait a little before leaving feedback, especially if the seller starts to inquire about the feedback soon after the sale, but sometimes it is best to wait just a few extra days, as this is ultimately the buyer's chip if something goes awry.  I guess one way to look at it is that it may have been a good learning experience for both parties in the end, sort of a silver lining to the headache endured, in order to help avoid the same issue in the future.
> 
> ...


 

 The thing that bothered me the most was that I repeatedly told him the tubes were not the same as the listing, maybe one was, but not the other. I needed a pair, NOT A SPARE! He kept on saying they tested the same and asked what kind of tester I had to verify the readings. I didn't fall into his trap, and stuck to my guns, the listing was not what I received.
  
 I'm not going to belittle him or post his ebay tag, as he has 100% feedback with a considerable history. He said he tested them 10 years ago, and knew not retesting them would bite him in the ass. I told him the listing was the problem, plain and simple.
  
  A tube NOS learning experience for sure, I"m happy it didn't blow my amp!!!!!!!!!


----------



## JK-47

mhamel said:


> Time to join the TU-8200 club.  I finished up my TU-8200DX build last week.
> 
> I went with all of the upgrade options Victor offers, including Amtrans oil caps for coupling. I also replaced the plastic 9-pin tube sockets with ceramic gold pin sockets, and the included volume pot with an Alps RK27 Blue Velvet (the section of the board where the volume pot mounts is designed to break away to accommodate the RK27 - one tip - if you go with the Amtrans oil coupling caps, the gold plated leads that get clipped off when the caps are soldered in make good bridge leads from the main board to the volume pot board if going with the larger pot)
> 
> ...


 
  
  
 Any updates on the tube rolling adventures?


----------



## catcherfly

I have a couple questions I'm hoping some of you might have answers for.
First off, I purchased a matched pair of Amperex 12AU7 Orange Globe tubes on eBay. I did not test the tubes before putting in the amp but everything is fine and I now understand the importance of testing first. I have been doing some research about testers and I'm wondering I could get some recommendations. Should I spend the money on a mutual conductance tester that reads Gm? The TU-8200 certainly won't be my last tube amp.
And secondly, one of the Amperex tubes makes a sound through the speaker it is on the side of, when I tap it with my finger. I can't hear anything unusual at any other time. Is this anything to be concerned with? 
I need to do some more A-B testing with the stock ECC82 before I can speak to the difference in sound. I do think it is a subtle difference, however.


----------



## JK-47

catcherfly said:


> I have a couple questions I'm hoping some of you might have answers for.
> First off, I purchased a matched pair of Amperex 12AU7 Orange Globe tubes on eBay. I did not test the tubes before putting in the amp but everything is fine and I now understand the importance of testing first. I have been doing some research about testers and I'm wondering I could get some recommendations. Should I spend the money on a mutual conductance tester that reads Gm? The TU-8200 certainly won't be my last tube amp.
> And secondly, one of the Amperex tubes makes a sound through the speaker it is on the side of, when I tap it with my finger. I can't hear anything unusual at any other time. Is this anything to be concerned with?
> I need to do some more A-B testing with the stock ECC82 before I can speak to the difference in sound. I do think it is a subtle difference, however.


 

 I noticed a considerable difference with the Amperex orange globes when listening through my headphones, more than through the speakers (I have sensitive Fostex FE168EZ's in folded horn enclosures) that the TU8200DX drives very nicely. Mainly in the mid's and hi's, with a vastly wider soundstage on my Fostex T50RastaPants 2's.
  
 I have also been considering a tester/testers. I think rather than buying a vintage tester that most likely needs to be rebuilt then calibrated, I will purchase something more modern... An Amplitrex AT1000 being the ultimate but some what pricey at $2700, the Maxi matcher II $700 (power tubes only), Maxi Pre Amp II $989 (preamp tubes only), Orange VT1000 $400-$500 (more of a go/no go tester). I'm leaning towards the two Max units at the moment. I figure in the long run they will save me $$$, time, and frustration. I could always sell them fairly easily in the future as well.
  
 A couple of great 6L6 and family reviews from 1998 and 2005. They are done in guitar amps though...
 https://www.watfordvalves.com/cgi-bin/documents/testreport_34.pdf
 https://www.watfordvalves.com/cgi-bin/documents/testreport_44.pdf
  
 here's their full page of different reports:
 http://watfordvalves.com/reports.asp


----------



## mhamel

jk-47 said:


> Any updates on the tube rolling adventures?


 
  
 Still burning things in, but so far the combo of 1950s Sylvania black plate 12BH7 and reissue Gold Lion KT-88 is my favorite.  I need to put some more hours on some of the other tubes before doing any sort of meaningful comparison.
  
   -Mike


----------



## mhamel

jk-47 said:


> I noticed a considerable difference with the Amperex orange globes when listening through my headphones, more than through the speakers (I have sensitive Fostex FE168EZ's in folded horn enclosures) that the TU8200DX drives very nicely. Mainly in the mid's and hi's, with a vastly wider soundstage on my Fostex T50RastaPants 2's.
> 
> I have also been considering a tester/testers. I think rather than buying a vintage tester that most likely needs to be rebuilt then calibrated, I will purchase something more modern... An Amplitrex AT1000 being the ultimate but some what pricey at $2700, the Maxi matcher II $700 (power tubes only), Maxi Pre Amp II $989 (preamp tubes only), Orange VT1000 $400-$500 (more of a go/no go tester). I'm leaning towards the two Max units at the moment. I figure in the long run they will save me $$$, time, and frustration. I could always sell them fairly easily in the future as well.


 
  
 I've got the Maxi Preamp II.  I've been very happy with it so far.  It's an additional $180 for adapters if you want to test 6DJ8-family tubes.  Another small preamp tube tester I've heard good things about is the Tube Imp.  It needs to be ordered from the UK and works out to around $500.   I came to the same conclusion about vintage testers. I really didn't want to have to go through restoring and re-calibrating a vintage tester.  I'd love an AT1000 but just couldn't justify spending that much on it.
  
 Up until the TU-8200DX, I didn't have a need to test power tubes, so I may end up picking up a Maxi Matcher II at some point.
  
    -Mike


----------



## mhamel

catcherfly said:


> And secondly, one of the Amperex tubes makes a sound through the speaker it is on the side of, when I tap it with my finger. I can't hear anything unusual at any other time. Is this anything to be concerned with?
> I need to do some more A-B testing with the stock ECC82 before I can speak to the difference in sound. I do think it is a subtle difference, however.


 
  
 This is called "microphonics" and is fairly common in tubes. Some tubes will be so microphonic that any small vibration will set them ringing. If you're only getting it when tapping directly on the tube, then just don't tap the tube.    If you have a set that's very microphonic you can also use tube dampers.  They range from simple high-temperature silicone o-rings to much more elaborate/expensive devices. Check out Herbie's Tube Dampers and the dampers offered by Brent Jesse Recording.  As with most things audio, you'll find endless debate on which may or may not work (or if they're worth using at all), but that's a debate for the sound science forum. 
  
 If you want to get more in depth on the subject, this is a good read:  http://www.thevalvepage.com/valvetek/microph/microph.htm
  
              -Mike


----------



## JK-47

mhamel said:


> Still burning things in, but so far the combo of 1950s Sylvania black plate 12BH7 and reissue Gold Lion KT-88 is my favorite.  I need to put some more hours on some of the other tubes before doing any sort of meaningful comparison.
> 
> -Mike


 

 What are the advantages/benefits of the 12BH7 tube? I've heard folks from other forums speak highly of them compared to the 12AU7...


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## JK-47

I've been emailing Peter at Maxi Test over the last several days, and he has been quick to respond. They offer a 10% discount if the MaxiMatcher II and MaxiPreamp II are purchased together, but they don't have the MaxiPreamp in stock until Mid March. I asked if I bought the Maximatcher II now for full price, and the MaxiPreamp II in March when they were back in stock, if they could apply the full $165 discount towards the Maxipreamp II. The only reason I asked if this was possible, was because Peter told me the MaxiMatcher II would most likely be sold out by the end of this week, and didn't know when they would be in stock again. He turned down my offer, and I felt like he was continuing to pressure me to buy the Maximatcher immediately as well as the back ordered Maxipreamp... not my cup of tea (he came across as very pushy the last few emails) . I still might go with the MaxiTest combo, but I'm considering biting the bullet and have just contacted Amplitrex...


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## Effusion

jk-47 said:


> What are the advantages/benefits of the 12BH7 tube? I've heard folks from other forums speak highly of them compared to the 12AU7...


 
  
 I haven't personally tried the 12BH7 tubes, therefore I can't comment on how they sound, however I would check with Victor and possibly Mr. Fujita first to make sure they are compatible.
  
 There seems to be some varying opinions on their substitution for the 12au7, as some have said the the heater draw is nearly twice that of the 12au7... so, better to check first before trying as you may just blow a FET like I did, which is never a good thing.
  
 Post below from the following link:  http://www.head-fi.org/t/183771/what-kind-of-tubes-are-compatible-with-12au7
  
 6/22/06 

 [img]http://cdn.head-fi.org/1/13/100x100px-LS-13ca4a84_3133-IMGP1613_resize.jpg[/img] 
 
sacd lover





 
offline
 
8,220 Posts. Joined 8/2002
Location: Ohio
 

   Quote:


 Originally Posted by *Ferbose*
_Thanks for the links.
 It is still unclear to me if putting a 12BH7 into a 12AU7 position is a good idea._

 

 The heater current draw of the 12bh7 is twice that of the 12au7 .... I wouldnt without knowing more about the circuit. But, in the tube substitute lists, I checked, the 12bh7 IS listed as a sub for the 12au7. However, its not listed as a preferred substitute ... which means in some circuits the 12au7 and 12bh7 will not be compatible.


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## Effusion

jk-47 said:


> I've been emailing Peter at Maxi Test over the last several days, and he has been quick to respond. They offer a 10% discount if the MaxiMatcher II and MaxiPreamp II are purchased together, but they don't have the MaxiPreamp in stock until Mid March. I asked if I bought the Maximatcher II now for full price, and the MaxiPreamp II in March when they were back in stock, if they could apply the full $165 discount towards the Maxipreamp II. The only reason I asked if this was possible, was because Peter told me the MaxiMatcher II would most likely be sold out by the end of this week, and didn't know when they would be in stock again. He turned down my offer, and I felt like he was continuing to pressure me to buy the Maximatcher immediately as well as the back ordered Maxipreamp... not my cup of tea (he came across as very pushy the last few emails) . I still might go with the MaxiTest combo, but I'm considering biting the bullet and have just contacted Amplitrex...


 
  
 I've heard mixed opinions regarding the Maxi testers, but they are generally not seen as being as versatile as other testers, as the tests they perform are pretty basic.  Also, since you have to essentially buy two testers, they are not a very cheap option, but since they are newer, you wouldn't have to worry about restoring or fixing them first and they would come with a warranty.
  
 The Amplitrex AT1000 is a pretty amazing tester and when hooked up to a computer can provide the most detailed analysis of how a tube does/will perform; however they are very expensive and are generally a bit of an overkill unless you have a ton of expensive tubes or are in the business of selling them.
  
 My recommendation would be to try to get one of the better older testers that is already restored and have it professionally calibrated.  Many will do everything and more than you would need and even with calibration, they will generally cost you much less than the Amplitrex or both Maxi testers.  I prefer Hickoks (I have a gold plate 533a), but there are several other brands that are pretty good as well, such as Sencore and B&K.
  
 Below is some info on older testers:
  
http://www.tubewizard.com/recommended_Hickok_testers.htm
  
http://radiolaguy.com/Showcase/TestEquipment/Gallery-Hickok-Test-Equipment.htm
  
http://www.alltubetesters.com/articles/tester_guide.htm
  
 Hope this helps!!


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## mhamel

effusion said:


> The heater current draw of the 12bh7 is twice that of the 12au7 .... I wouldnt without knowing more about the circuit. But, in the tube substitute lists, I checked, the 12bh7 IS listed as a sub for the 12au7. However, its not listed as a preferred substitute ... which means in some circuits the 12au7 and 12bh7 will not be compatible.


 
  
 I think I've been the guinea pig on this one.  FWIW, I've got around 50 hours with 12BH7s in the amp so far without issue.
  
    -Mike


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## Effusion

Very cool and very good to know... after 50 hours, the circuit of the Elekit can definitely handle any differences they might have!
  
 What type/brand of 12BH7 are you using?  Any impressions on the sound signature they provide?
  
 Edit:  Sorry, just noticed that somehow I missed the last 4 posts or so on page 6, I guess I wasn't paying attention 
	

	
	
		
		

		
		
	


	




.  Let us know what your ultimate verdict of the 1950s Sylvania black plate 12BH7 tubes are!


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## Effusion

JK-47,
  
 Not sure if this helps at all, but I remembered reading about some of the issues that were found with the Amplitrex AT1000 and found the link again, below:
  
http://jacmusic.com/Tube-testers/Amplitrex/index.htm
  
 Now, it is more or less his opinion (as he states), but I remember after reading it, even though I'm not sure about all the technical aspects he describes, it kind of made me cross-out the Amplitrex AT1000 as a possibility, at least for me (other than the really huge price tag).
  
 Also, to clarify my post above, I got confused between the Orange VT1000 and the Maxi Preamp tester (long day), as it is the Orange tester that is very basic in its test, whereas the Maxi is quite elaborate and would make a fine tester for your uses.
  
 In addition, if you were wondering at all, I purchased my Hickok 533a for $350 and it had seen very little use over the years and was in really nice cosmetic shape; generally a professional recalibration will cost about $150, but you have to ship the unit if you can't find anyone locally.  After recalibrating, you can use special calibrating tubes (~$50) and a specific process to keep the tester in calibration; best to test once or twice a year if under use, but supposedly using these tubes/process correctly you will not need another full calibration, at least for a long time.  Now, the 533a is probably the cheapest of the better Hickok testers out there, but there are better models, however at higher prices.


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## JK-47

mhamel,
  
 I asked Victor if 12BH7 tubes were ok... he said "NO", please be careful.
  
 Effussion,
  
 Thanks for the great info, I will be weighing all my options over the next few weeks before I make my final decision. I ran across the recommendations from alltubetesters.com a while ago, and found most of the Hickok models difficult/near impossible to find, or expensive buy it now auctions ($1000-$1500 for Hickock 539 series, or high $$$ bidding wars). If I saw something similar to yours, I would be all over it, but if I'm going to spend $1500+ I'm leaning towards the MaxiTest pair still.
  
 There was an auction that just ended ,for an original untested (seller only said it turned on) MaxiMatcher. The original retailed for $500, and this well worn (badly faded face plate) sold for a little over $500 with shipping, crazy! I've seen models sold over the last year in much better condition on audio/tube sites for apprx $400. I lost interest in the latest auction as soon as the bids went over $200.
  
 I looked into the Tube Imp also, and for $500, It doesn't quite sell itself to me, definitely $300-$350, maybe $400...
  
 Geez, this quest for a tester is almost as bad as chasing tubes, lol
  
 Greg70,
  
 Is your amp back up and running?


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## Effusion

Good to know Victor has worries and said not to use them.  I'm wondering if maybe over time they will start to cause issues or eventually wear a component out.  When I used the QV05-25 power tube, it only took about 5 min. or so to blow the FET, but later I found out that the plate voltage for this type of tube is out of spec, so that may have been more of what did it so fast, compared to the potential heater draw issue with the 12BH7.  Plus, it was a power tube and not a signal, etc... but I'm definitely not an expert on the Elekit's circuit design.
  
 I'm always very glad to help, when I can and you are taking the best approach by weighing all options first.  The Hickoks go very fast and some demand a high price, mainly because those who are buying them want to use them to test tubes in order to sell them, as Hickok results seem to be trusted more, especially for high price tubes.  There are other options such as the Sencore and B&K, which are both pretty good too.  A pretty basic Sencore will at least tell you that a tube doesn't have shorts/leakage and has life left, however some models won't give you an accurate MC reading, which is helpful when matching pairs and buyers may not bid high when using its test results (probably a maybe though).  Also, for the price the Orange tester just doesn't do enough to justify the cost, but it will tell you if the tube is dead or has a short.
  
 Keep up the search and try to learn as much as you can to make the most informed decision possible.  Probably best to view the tester as an investment if you plan to buy a lot more tubes in the future, plus if the resale value of the Maxi testers looks to be high, you could always sell them if you find another better option down the road.  Anyway, the Maxi's should work great if you decide to go with them.
  
 Let us know what you ultimately decided to do and good luck on the search, you never know when a nice 533a might pop up for sale!


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## mhamel

I had sent an email to Elekit Japan to get some more details on the heater circuit current capacity, but haven't heard anything back yet.
  
 So, I probably should have dug into this before just plugging them in, but here's what I found... I think I'm looking at this correctly:
  
 From the schematic it shows 4A from the transformer on the 6v tap, but I don't know if that's the max spec for that transformer or not.  That tap powers the DC heater circuit for the pre tubes and directly powers the heaters of the power tubes via AC. The DB107 rectifier for the pre tube heater supply is 700v / 1A. It's probably ok doing 1.2A @ 6v, but I haven't done a thermal check on it yet. It would be simple to drop in a 50V 1.5A rectifier in the same DIP-8 package to be safe, they're $0.46/ea from Mouser... so I think I'm going to do that.
  
 Combining the 12BH7 with some of the supported output tubes looks like it will exceed the 4A rating on the schematic.  Checking the heater current draw for supported tubes:
  
 Pre:
 12AU7 - 0.3A parallel
 12BH7 - 0.6A parallel
  
 Power:
 6L6GC - 0.9A
 6550  - 1.6A
 KT88  - 1.6A
 KT66  - 1.3A
 EL34  - 1.6A
 KT90  - 1.6A
  
 It looks like the way I'm running it right now exceeds the 4A spec on the schematic by 400mA.   I haven't had any issues, but to stay completely within spec, at least until I hear back from Elekit, I'll probably drop back to the 12AU7 family tubes if I stick with the KT88, 6550, EL34 or KT90, which would draw 3.8A.  Switching to the KT66 with 12BH7 would also draw 3.8A, so should be ok.  The 12BH7/6L6GC combo draws even less, at 3A.
  
 If Elekit responds that the 6v tap on the transformer can handle 4.4A or higher, there may be no issue at all running 12BH7 tubes with the higher draw output tubes.  I'll share whatever I hear back from them.
  
  
     -Mike


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## Effusion

Thanks for doing the research and for contacting Elekit.  It would appear that something is at least working well with them, since you have so many hours safely logged, but I guess you never know over time or when using different output tubes, etc.; probably best not to chance it until you know for sure.  The great thing about this hobby is that you learn something new everyday!
  
 I'll be anticipating Elekit's response, as you've intrigued me into trying a pair to see how they sound and how they compare to other variants; that is, if it is determined to be safe to use them with the stock components.
  
 Thanks again for digging deeper!


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## JK-47

mhamel,
  
 I emailed Elekit in Japan a while back regarding a power tube (I can't remember which one), and they gave a response within 24hrs. I'm amazed how quickly Elekit and Victor respond...
  
 Thanks for the technical update regarding the current draw of the various tubes. I can barely read a schematic, not to mention I forgot one was included in the instruction manual.


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## satwilson

Been following this thread for a while, don't have the Elekit yet but plan on purchasing soon. The Schiit Lyr was my gateway back into tubes, and I have many sets of Amperex, Telefunkens, etc for rolling. My comment today is regarding tube testers. A few months back I picked up a Sencore TC154. While not as accurate as an Amplitrex or some others, it certainly does a great job performing your basic tests for shorts, grid leakage and emmissions, and matching sets of tubes. I bought mine on Ebay, "in good working order" and after getting a calibration module and repair manual, am very pleased with its performance. All told less than $160. The key is getting one in good condition. All I needed for mine was to calibrate it, which is pretty easy. Here is an article at Tubesound detailing the Sencore "Mighty Mite" testers   http://tubesound.com/2007/10/24/sencore-mighty-mite/


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## Effusion

Thanks for the comment about the Sencore "Mighty Mite", those are really great inexpensive testers that definitely get the job done.  They really do all that you really need, even if the emissions test is a little harder to use to match than a true MC rating; matching, to a point, isn't the most important thing all the time.  As long as you can test for shorts and leaks and a pair is both similar in make and also close on emissions you should be good to go.  I may be wrong on this, but I believe a huge plus to the "Mighty Mite" is that it is fairly easy to calibrate accurately yourself, unlike most of the Hickoks, which require a bit of complex know-how.
  
 Let us know if you have any questions regarding the Elekit before you purchase.  It is a great amplifier and even though I've never owned the Lyr, I don't think you'll be disappointed in the Elekit at all, especially if you are into tube-rolling as the options are almost endless.


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## mhamel

effusion said:


> Thanks for the comment about the Sencore "Mighty Mite", those are really great inexpensive testers that definitely get the job done.  They really do all that you really need, even if the emissions test is a little harder to use to match than a true MC rating; matching, to a point, isn't the most important thing all the time.  As long as you can test for shorts and leaks and a pair is both similar in make and also close on emissions you should be good to go.  I may be wrong on this, but I believe a huge plus to the "Mighty Mite" is that it is fairly easy to calibrate accurately yourself, unlike most of the Hickoks, which require a bit of complex know-how.
> 
> Let us know if you have any questions regarding the Elekit before you purchase.  It is a great amplifier and even though I've never owned the Lyr, I don't think you'll be disappointed in the Elekit at all, especially if you are into tube-rolling as the options are almost endless.


 
  
 I've got a Lyr 1... it's a great amp, and the 2 is supposed to be even better.  However, even after rolling an insane number of tubes through the Lyr, I never quite got it to sound right with my LCD-X. Interestingly enough I liked the Lyr with the LCD-2, but I thought it made the X sound too thick and closed-in. At this point the Elekit has pretty much shelved the Lyr.


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## mhamel

effusion said:


> Thanks for doing the research and for contacting Elekit.  It would appear that something is at least working well with them, since you have so many hours safely logged, but I guess you never know over time or when using different output tubes, etc.; probably best not to chance it until you know for sure.  The great thing about this hobby is that you learn something new everyday!
> 
> I'll be anticipating Elekit's response, as you've intrigued me into trying a pair to see how they sound and how they compare to other variants; that is, if it is determined to be safe to use them with the stock components.
> 
> Thanks again for digging deeper!


 
  
 Sure... happy to. That's part of the fun of DIY to me.
  
 I did hear back from Elekit, but I also sent a few more questions. While the pre tube heater circuit was designed for the 300mA/tube draw of the 12AU7, it can handle a limit of 450mA/tube. They said that running the 600mA draw of the 12BH7 over time "may" eventually damage the transformer, but that it should be ok to test out.
  
 From that, my additional questions were:
  
 1. Is the preamp heater circuit limit due to the overall 6v output of the transformer (which is what it sounded like) or a limit of that specific part of the overall heater circuit?
 2. If #1 is true for the transformer load, is it then safe to run the 12BH7 when using power tubes that draw less heater current like the KT66 and 6L6GC with no other changes to the amp?
 3. Would replacing the 1A rectifier in the preamp tube heater circuit with a 1.5A part make sense?
  
 I'll update again when I hear back.
  
    -Mike


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## teamrushpntball

Was curious if anyone has gotten to compare this and the Woo WA2 by chance?  Not real concerned about the speaker amp portion, albeit that is a nice bonus.  
  
 These 2 have become my likely next upgrade amp.  Hoping to get a few opinions before making a purchase since it's unlikely I'll ever get to hear this amp unless I bought it.


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## mhamel

mhamel said:


> From that, my additional questions were:
> 
> 1. Is the preamp heater circuit limit due to the overall 6v output of the transformer (which is what it sounded like) or a limit of that specific part of the overall heater circuit?
> 2. If #1 is true for the transformer load, is it then safe to run the 12BH7 when using power tubes that draw less heater current like the KT66 and 6L6GC with no other changes to the amp?
> 3. Would replacing the 1A rectifier in the preamp tube heater circuit with a 1.5A part make sense?


 
  
 More updates from Elekit.
  
 The limit is a combination of the output capacity of the transformer and the rectifier in the pre tube heater circuit. They suggested using a rectifier with approximately 2x capacity of the expected current draw for the heaters. I ordered a 1000v/2A rectifier to drop in but if that runs too hot I will go up to a 3A, which will require a bit more work to fit as the package size is completely different. As long as the rectifier is upgraded, it should be fine to run the 12BH7 with lower-draw power tubes to keep the total load on the 6v secondary < 4A.
  
 I've also reached out for a couple of quotes on a custom transformer to replace the one that came with the kit, with the 6v secondary winding supporting 4.5A.
  
     -Mike


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## catcherfly

mhamel said:


> This is called "microphonics" and is fairly common in tubes. Some tubes will be so microphonic that any small vibration will set them ringing. If you're only getting it when tapping directly on the tube, then just don't tap the tube.    If you have a set that's very microphonic you can also use tube dampers.  They range from simple high-temperature silicone o-rings to much more elaborate/expensive devices. Check out Herbie's Tube Dampers and the dampers offered by Brent Jesse Recording.  As with most things audio, you'll find endless debate on which may or may not work (or if they're worth using at all), but that's a debate for the sound science forum.
> 
> If you want to get more in depth on the subject, this is a good read:  http://www.thevalvepage.com/valvetek/microph/microph.htm
> 
> -Mike




Thanks for your reply Mike. I really appreciate it. I am aware of microphonics but didn't know what degree is "acceptable" with tubes and if it is a sign of a bad tube.


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## JK-47

mhamel said:


> More updates from Elekit.
> 
> The limit is a combination of the output capacity of the transformer and the rectifier in the pre tube heater circuit. They suggested using a rectifier with approximately 2x capacity of the expected current draw for the heaters. I ordered a 1000v/2A rectifier to drop in but if that runs too hot I will go up to a 3A, which will require a bit more work to fit as the package size is completely different. As long as the rectifier is upgraded, it should be fine to run the 12BH7 with lower-draw power tubes to keep the total load on the 6v secondary < 4A.
> 
> ...


 
  
 Nice!!! Are you going to show us all a few pics when you do the transplants?


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## LingLing1337

Will this amp be good for speakers that are 91 db sensitive at 8 ohms? I will keep it for headphones either way but if it could power my speakers that would be a nice bonus.


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## Effusion

The Elekit ran my Energy RC-10 monitors, which are 91 db at 8 ohms, great and with plenty of volume for a smaller room in Triode mode.  Unfortunately, I haven't been able to use the Energy RC-10s much as I've loaned them out recently, but the Elekit seemed to drive them just fine and they sounded great!
  
 Info on the RC-10s:
http://www.energy-speakers.com/bookshelf-speakers/?sku=RC-10
  
 You can always change the jumper to Ultra-Linear mode in order to squeeze out a little extra juice, but if your speakers are similar to the RC-10s, it shouldn't be an issue in either mode.
  
 I believe quite a few other owners here use the Elekit regularly with their speakers as well... does anyone want to share more details on the speakers they run with the Elekit and how they sound?


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## JK-47

I have Fostex FE168EZ (94.5dB sensitivity) drivers in Madisound BK-16 folded horn enclosures. My TU8200DX can drive them to very loud levels in Ultra Linear mode with the volume at 11-12 o'clock, more than I'm comfortable with, playing in my apartment (downstairs neighbors complained about bass when volume was at 10 o'clock).

Flat EQ, I very rarely EQ the music I listen to.


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## mhamel

jk-47 said:


> Nice!!! Are you going to show us all a few pics when you do the transplants?


 
  
 I definitely will. The custom power transformer is being built now, it will take a couple of weeks to get here after it's finished. I also tracked down the connectors being used so I can wire up the new transformer to plug into the existing connectors on the boards. Those are probably another week or two out, too. I have the new rectifier here, but will do it all at once when all of the parts are in.
  
    -Mike


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## LingLing1337

Thanks for the impressions. I will pick one up tomorrow and ill be sure to post impressions with my paradigm monitor 7.


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## vkung

Here are the _latest_ trend in _Japan to modification TU-8200 with Amtrans AMRG 3/4 W AMRG Carbon Film Resistor_


  http://www.amtrans.co.jp/products/amrgj/index_e.shtml
  
 Stereo Sound offers TU-8200 with the following upgrade parts (only 22 3/4W AMRG)
 http://store.stereosound.co.jp/products/detail.php?product_id=2062
  
 AMRG 3/4W skeleton 
 12 ohm: R3,4,19,20,21,22
 180 ohm: R37,38
 1K ohm : R5,6,11,12,35,36
 22K ohm : R29,30
 100K ohm : R1,2,15,16
 330K ohm : R9,10
 AMRA 1W 27K ohm :R7,8,13,14
 AMCH  3300PF : C17,18
 AMCO  0.1μF: C3,4,9.10
  
  
  
 I  installed  TU-8200 PCB 1 with  all Amtrans AMRG 3/4 W except  :R7,8,13,14 with AMRA 1 W
  

  
 This PCB installed with Amtrans AMCY oil coupling caps.

  
  
 For PCB Unit -2
 This section is important for Headphone lover
 TU-8200 is using  4 resistors tapped to the OPT.  
 I installed  15 ohm 2W  AMRG  plus all 3/4 W AMRG plus 2 AMCH 3300pf


----------



## LingLing1337

Im going to grab new production psvane tubes all around, kt88 and 12au7. Can anyone recommend some NOS tubes also? Mostly looking for synergy with Grados.


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## JK-47

Just got back home from work, and picked up a literal mountain of boxes from the post office. Included in that mountain were my Maxi-Matcher 2, and Maxi-PreAmp 2 tube testers. The Maxi's are very easy to use, and have already made a difference when it comes to weeding out poor performing NOS tubes. Some readings were very close when measuring transcondcutance, but the plate current's were almost double in some cases (supposed matched pairs). Will the amps auto Bias make up for the difference in plate current or should I not bother putting them in?
  
 I'm rolling through the power tubes today. GE 6L6GC's, RCA 6L6GC Black Plates, Gold Lion KT88's, Philips 7581A's, Sylvania 6L6GC's, GE branded Mullard EL34 XF2's (beware the fakes, I sent back a pair already, with no complaint from the seller. He must have known...). Impressions later tonight, and input tube will be done tomorrow.


----------



## Greg70

lingling1337 said:


> Im going to grab new production psvane tubes all around, kt88 and 12au7. Can anyone recommend some NOS tubes also? Mostly looking for synergy with Grados.


 

 For me, the EL34 family was by far the best with my Grados. The EL34 mids compliment the Grados.
  
 The KT88s were very impressive with a short listen, but overbearing in the bass department and quickly became fatiguing.. better in Triode mode but still more than I could bear.
 The Mullard re-issues will tell you if EL34s are the right choice for you, and from there the NOS Mullards are the way to go.
  
 BTW- if someone's looking for PSvane KT-88s, I have a pair here with only a few hours on them.. first grade direct from PSvane.


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## LingLing1337

How much are you looking for for the pair? Sorry id pm you but I don't think I can on tapatalk


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## Greg70

OK.. sorry for posting this here and hope we're not breaking the rules.
 They're TII Collection Grade A (Best) in the gift box. Cost USD$250.. I'd be happy with USD$150 shipped and I'll wear the PP fees.


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## JK-47

A quick power tube update...
  
 RCA 6L6GC Black Plates: A very nice balanced tube, fantastic mids, maybe a little pricey  (I think I got a great deal for this pair though), fantastic soundstage
  
 Sylvania 6L6GC: Fair, but maybe a little dry sounding, missing a little of that mid range magic... I will periodically try them out again.
  
 Mullard EL34 XF2's: Magical mid range monsters, very nice
  
 Philips 7581A's: Tested strong NOS values, I'm going to let these burn in for a while, they are dead silent on my headphones (modded T50RP's) all the way to max volume with no sound source! My other tubes start to hiss ever slow slightly at 3 o'clock on the volume dial. So far they are very accurate and controlled, somewhere in between the RCA plack Plates (beautiful soundstage and mid-range) and my current favorite GE 6L6GC (warm, with a nice low end).
  
 Gold Lion KT88 current production: So far my least favorite, but I will give them a chance to burn in. They sound flat and lifeless so far compared to everything else.


----------



## Greg70

Great to hear people's tube impressions here.
  
 I've tried a heap of preamp tubes, and for me the clear favourites are Amperex 7316 and Tesla (NOS) ECC802S.
 The Teslas are a little brighter, but they have fantastic detail. They're my choice on everything except bright recordings.
 The Amperex are pretty faultless everywhere.
  
 My amp is fully repaired and back in action after the faulty tube incident.. thanks to Victor for his help.


----------



## JK-47

greg70 said:


> Great to hear people's tube impressions here.
> 
> I've tried a heap of preamp tubes, and for me the clear favourites are Amperex 7316 and Tesla (NOS) ECC802S.
> The Teslas are a little brighter, but they have fantastic detail. They're my choice on everything except bright recordings.
> ...


 

 Good to hear you're back up and running!!!


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## LingLing1337

Yeah im not sure whats up, I have quite a few posts here but I cant pm or post in the for sale forums. Oh well.

Anyway I have several tubes on the way. Rca clear top, Amperex Bugle Boy, and PSVane 12au7-t mkii. For power tubes I just have mullard el34 and tung sol 6l6gc on the way. Will post impressions next week.


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## JK-47

lingling1337 said:


> Yeah im not sure whats up, I have quite a few posts here but I cant pm or post in the for sale forums. Oh well.
> 
> Anyway I have several tubes on the way. Rca clear top, Amperex Bugle Boy, and PSVane 12au7-t mkii. For power tubes I just have mullard el34 and tung sol 6l6gc on the way. Will post impressions next week.


 

 Did you build the amp yourself or purchase it assembled?
  
 Right now I'm enjoying the Philips 7581A's and CBS/Hytron 5814A's, they complement each other nicely. As the 7581A's start to burn in more they are losing their slightly harsh edge.
  
 Late last night I had the Mullard CV4003's in and felt they slightly pushed the mid-range up a tiny bit too much for my taste. Both the Mullards and the CBS have a touch less going on in the top end compared to my Amperex Orange Globes.
  
 So far I would dare to say Mullard tubes are mid-range monsters, whether they are power or input tubes.


----------



## Mr Chance

Hi, long time lurker, first time poster.
  
 So I found this amp kit on the net and contacted Victor about it, and I have to take my hat of to him, what a nice man and great salesperson he is! How ever I ended up buying from Japan since the Swedish krona have taken a bit of a plunge compared to the US$. Emi at Elekit is by the way also very nice to deal with. This was my first built and except from mounting one of the tube sockets 90 degrees wrong and bridging two pins on the 40-pin connector so bad that they couldn't be separated, I pretty much nailed it 
  
 Since I didn't have a DAC for the amp initially I fired up my old Rega Planet CD-player. My Audio-Technica W5000 sounded really bad! And I thought that wasnt what I expected since I bought this amp specifically because it is one of few tube amps that can handle low impedance headphones. I then tried my old Sennheiser HD600 and they have never sounded better!!! Fantastic! I read up and understod that changing to triode mode would probably make the AT-headphones sound better. It did. Much better. But still not better then the 600s. I then tried playing music from iPhones 3.5mm jack to the 3.5mm jack on the amp. That also worked in favor of the ATs. With that set up they were getting much closer to the HD600s.
  
 So a few days later I got my Arcam irDAC and now the W5000s were on par with the HD600s even though they sound very different. They are good in different ways. But what I want to improve on is vocals and so I asked my local HiFi store repairman and tube-guru what would be the best tube for better vocals. He recommended JJ EL34 or if I was willing to spend some more money the Genalex Gold Lion KT77.
 So my questions, being a complete tube newbie, is:
 1) Is the KT77 compatible with this amp or will it blow up in my face if I try this out?
 2) I never believed in "burning in" audio equipment, then again I never owned anything with tubes before, but now it seams that vocals are actually getting better and better with the W5000s. I would say the tubes has been on fore about 50-60h. When will they be fully burnt in?
 3) Would a pair of TAD 12AU7WA make any difference or could I just stay with the tubes that came with the amp? Any other suggestion in that pricerange? Preferably not NOS (until I get more familiar with tubes I think I stay with new productions).
 4) Why is it that you never see preamp tubes sold as matched?
  
 Sorry if these are stupid questions, but I would be very thankful if someone with better knowledge about tubes would take time to answer them!


----------



## vkung

PSVANE MKII  12AU7  + KT88 
Wow. What a nice upgrade. So far, *PSVANE* MARK II is the best tube set for TU-8200DX.
The MKII series offers superb sound quality. The new coating materials offer an even better music presentation. You will experience slight 3D imaging improvement, layering and clarity.


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## JK-47

Mr Chance,
  
 Welcome to the TU-8200 club!!!
  
 If you take the time to read the entire thread, you will find many reviews and opinions on NOS/Vintage tubes. Effusion, the fellow that started this thread is a great source of knowledge, and will gladly answer questions.
  
 I have limited experience with new tubes (only the stock Electro Harmonix 6L6's,made in China 12AU7's, and New stock Gold Lion KT88's), and I have to say the older tubes beat them hands down.


----------



## JK-47

Its been a long day of tube rollin' 
  
 Mullard CV4003: Huge mid range boost, compared to the other tubes in my arsenal, when people talk about "the Mullard mid-range" they aren't joking. Nice soundstage.
  
 CBS/Hytron 5814A: A little less mid range, and more in the top and bottom than the Mullards, better balance overall, I like this tube a lot, nice and easy on the ears, smooth large soundstage.
  
 GE 5814A: surprisingly decent for budget tubes (I paid $21 shipped for the very tightly matched pair), the top end is slightly more predominant than anything else. The mids and lows are less represented by this tube, but still decent  for the $$$.
  
 Philco/Lansdale 6189/12AU7WA:  took a chance on this tube and have to say I'm impressed. Very similar in sound to the CBS/Hytron 5814A, maybe even a tiny bit more balanced overall, with a smidgen more width and detail in the soundstage. Overall this black longplate is my current fave.
  
 Amperex Orange Globe: Nicely detailed and wide soundstage (virtually the same as the Philco/Lansdale's), a tiny bit brighter up top than all the others without a loss of mids or lows. Still one of my top picks.
  
 In order of brightness: Amperex>GE>Philco/Lansdale>CBS/Hytron>Mullard
  
 The Philips 7581A's were in the power tube sockets for all these tests. I have to say, if power tubes are the color... the input tubes are the shades. Like Effusion has said, the power tubes will have a larger impact on sound, and the input tubes will add or detract slight nuances.


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## JK-47

I left the Gold Lion KT88's marinating in the MaxiMatcher at 400V's for almost 40hrs. It seemed to have helped burn them in a bit. They sound much better, than the first audtion. Still not quite as detailed and lush as other old school tubes, but not too shabby at all.
  
 So far my new faves are the Philips 7581A's, punchy, detailed, fantastic soundstsage, and great across the entire frequency spectrum.


----------



## Effusion

JK-47,
  
 Congrats on the new testers, I'm sure they're getting plenty of use!  As far as your question regarding matched plate current with power tubes, it is my understanding that while you do want to have a pair as closely matched as possible, the GM is generally more relevant unless you have an amplifier in which you set the bias, and is pretty much fixed.  Now, you definitely don't want to use tubes that are out of the specification or even extremely close to the limits, as this could mean they have serious issues, but I believe that because of how the Elekit was designed, with the automatic bias control, you should probably be okay using two tubes with different, but in-spec ratings.  However, I'm not an expert, so contacting Elekit may provide the best and most accurate answer.  Off hand, the large majority of the power tubes I have tested have been pretty close in these voltages, but I do have a few that did test differently, but sounded fine in the Elekit and didn't give me any problems; however, I'm not saying that over time they might cause issue, only Elekit would probably be able to best answer that question.  You may also want to "burn-in" the tubes prior to testing, at least 24 hours and up to 48 if you want the most accurate readings; this is especially true with NOS tubes as they are older and many have not even been turned on in decades.  Below are some links to some more interesting information regarding the matching process:
  
http://tctubes.com/power-tube-testing.aspx
  
http://www.thetubestore.com/Resources/Matching-and-other-tube-info/Power-Tube-Matching
  
 Thanks for posting your impressions of the various tube variants that you have used with the Elekit!  I also agree with how you have described the sound of each, for the variants I have used with the amp and with my cans; it's nice to have this information out there to help others contemplate which to try.  Not all tubes will sound the same in different systems, but generally if you have a nice reference system you can discern what characteristics they will generally give, thus it can really help others find what they are seeking out in their own system.  I have not tried the 7581As yet, only the KT-66s, which I enjoy probably the most, but I'm now very intrigued!
  
 Continue to let us know how the impressions are going, but remember to take breaks as ear fatigue can really getcha!  
	

	
	
		
		

		
			




  
 Mr. Chance,
  
 Congrats on the purchase and welcome to the club!  I hope the following might help answer your questions:
  

KT-77
My understanding was that the KT-77 are an acceptable variant for use in the Elekit, however I have unfortunately never tried them in my unit, so I can't really give an absolute go ahead type of answer.  If you give Elekit a quick e-mail, I'm sure they'll let you know if the ones you are looking at are a go or not.

  

Burn-in
I'm definitely in the burn-in makes a difference camp, but I believe it ultimately depends on equipment; amps vs. DACs vs headphones, etc.  My Elekit drastically changed after about 30 hours or so, which from then on everything got tighter and more controlled up until about 80 to 100 hours, when it leveled out and has been the same since.  As regards to tubes, many do believe they need burn-in as well, and, at least to a certain degree they are probably correct.  For example, those that do a lot of testing of older NOS tubes will admit that they have seen tubes with high levels of gas initially, but after about 30 hours burn-in, most of the time the gas has almost completely go away; test results also change within the first 48 hours or so.  These tubes have designs to keep them running for long periods of time, for example with the getters, which remove free radicals and such nasties during operation, but even a tube that has just been sitting around for 50-60 years will probably benefit from a little burn-in as it sorts itself out after sitting for so long.

  

Power tubes
I recommend replacing the EH 6L6GCs, as they are not best of this variant, not bad, but there are definitely better out there.  As far as new production, unfortunately I have not tried many varieties; I have almost all NOS tubes, but regardless of that, it ultimately depends on what you are looking for.  I really like my McIntosh KT-88s that are newer production and even the SED Winged "C" weren't bad (they are a little older than truly "new" though).  Victor has had great success with the new production Psvane variants, as many others have as well, however they are a little pricey.  I guess it really depends on how much you want to spend and what sound signature you are currently lacking with the stock tubes, in your system, and with your headphones... so, where do you want to go?

  

Matched Preamp tubes
Actually, quite a few sellers/stores sell/offer matched preamp/signal tubes such as the 12au7s.  However, it really isn't as important as matching the power/output tubes as the current draw is so much larger; variations in tube performance can cause shortened life and inferior sound in the power tubes.  Small preamp tubes will generally sound just as good heavily used as they do new and over time the sound quality will generally not degrade as the tube nears the end of its life; however you get what you pay for, so try not to spend too much on really used up 12au7s.  In contraction, the sound quality degradation from power tubes will generally be perceivable as they reach the end of their life.  As a result, always try to get matched power tubes with plenty of life left and if you have no choice, spending less on used preamp tubes is generally okay, but not preferred.

  
 I hope this helps, but let me and the rest of the club know if you have other questions.


----------



## Mr Chance

JK-47,
  
 Thank you!  I have been through this thread twice so It's not a lack of effort that makes me ask these questions. KT77 is only mentioned one time in 130 posts and that's in a copy of a review, but  that's maybe enough to answer that question?
 About the questions regarding pre amp tubes and what to get it's not always that easy to understand what tubes people in here are referring to and where you could get them from a reliable source. And since I don't have any equipment to measure tubes I would be more comfortable with new production tubes for the moment.
  
 PS: Thank you for giving a new opinion about the KT88s after burning them in!


----------



## Effusion

Mr Chance,
  
 I understand your frustration, tubes are a pretty crazy business, especially NOS.  Generally you can use eBay as a reference for "going" rates on many variants and as a baseline.  Although, as with many things, eBay is hit or miss sometimes, but there are also quite a few retail websites that offer new production as well as NOS variants, with an added piece-of-mind, but generally at a higher price.  TubeWorld.com is a great reference for NOS tubes, as there are a ton of pictures and explanations.  If you plan to buy Chinese, I would suggest going with someone based in the states that do a burn-in period before matching pairs; most of the factory matched cheaper Chinese tubes are not really matched well at all and variations are common.
  
 Is there any type of sound signature that you are after in particular?  What type of headphones do you use and what kind of music to you typically listen to?
  
 Each variant will change the sound signature, either for the better or for the worse, depending on your own preferences and system.  However, there are tubes that are generally inferior in overall sound quality, when compared to others, with higher end variants giving blacker backgrounds, improved resolution, and better soundstage.


----------



## Mr Chance

Effusion,
  
 thank you for that detailed answer! I really appreciate you taking time to help out!
  
 I have already sent Emi an e-mail about the KT77 and also asked if there is a complete list of accepted tubes.
 The reason why I'm looking in to the Genalex Gold Lion KT77 is that I want just a bit more clarity/presence/detail in vocals (female) and maybe an over all more "air" (does that make any sense?). I also been looking at TAD EL34-SVT but I think that might be a bit to much.
 As for my budget, sure I could buy Psvane but not until I'm a bit more educated about tubes.
  
 Again, thank you for your detailed answer!


----------



## Mr Chance

effusion said:


> Mr Chance,
> [...]
> Is there any type of sound signature that you are after in particular?  What type of headphones do you use [...]


 
  
 I want just a bit more clarity/presence/detail in vocals (female) and maybe an over all more "air" (does that make any sense?). I listen to mostly Jazz, a lot of it being vocal, and opera. I use Audio-Technica W5000 as my main headphones but I also have a pair of Sennheiser HD600.


----------



## JK-47

Effusion,
  
 The tubes that I questioned were GE 7581A/KT66's, they were very close in transconductance (Less than 5% difference, and NOS spec), but the current draw on the plates were vastly different... 39mA in one and 21mA's in the other (the current range is 12mA-40mA, so one was right at the uppper limit).  I ended up reluctantly returning them, I got them for a great deal and wanted to keep them. Even with the TU-8200's auto-bias, it seemed like the best thing to do was return them.
  
 My current audio setup is far from "Audiophile Grade", either my MacBook Air or an older PC laptop that is used as my TV media center supply the music (generally FLAC or 320kbps mp3). Then it's on to a Schiit Modi 2 Uber supplying the TU-8200. The Modi 2 has more options (16/24bit 44-192kHz) vs the Elekit DAC that sits inside the TU-8200 (16bit 44-48kHz). Either Focal Spirit Pros or my modded Fostex T50RP's do the honors headphone wise, via a 20' DIY Mogami mic cable I put together. My TV is plugged into the Modi 2 via TOSLINK and I watch tv with the TU-8200 and Fostex Speakers.


----------



## john57

Is the EL34 tubes generally the more transparent sounding tube?


----------



## Effusion

Mr Chance,
  
 You're very welcome, and I hope the following helps.
  
 I haven't been fortunate enough to hear the Audio-Technica W5000s, so I can't really comment on them so much as the HD600s, which I had for a brief period years ago and are also very close to the HD650s.  For Jazz and classical, especially with female vocals, you probably want a smooth and high resolution mid-range, with a little sparkle up top.  I agree, I also tend to really like great air or space in the sound, making live recordings "feel" live, so soundstage would also be important as well.
  
 It is hard for me to say what new production tubes would benefit you the most, as I haven't tried too many, but I have had good luck with the Macintosh KT-88s, which are my daily multi-use pair.  However, you may find that you really like the EL34s in general, which I've found to add a great amount of air with the addition of a little extra mid-range magic, especially in the upper mid-range.  You could try the new production Mullards by New Sensor Corporation, or the SED Winged "C", both Russian companies, if just to see if they are your flavor, but ultimately either the Telefunken, which have really great upper mid-range and highs, or the NOS Mullards from the Blackburn factory, which give some of the best mid-range and sound a bit more full than the Telefunkens, will probably give you the best in overall sound quality for this type.
  
 The same really goes for the 12au7s, I've only tried the Telefunken smooth plate, but it was very nice in upper frequencies, while the Mullards are generally mid-range beasts, with the Brimars being similar, but giving just a bit more resolution; the Mullards may be a little too laid-back with your HD600s/cable, which might over-emphasis the Senn "veil".  Also, many have had good luck with the Amperex, either orange globe or bugle boys.  As far as new production, many have found the Psvane 12au7, mark II I believe, to be very nice, and may work well for you; Victor is a good source of information on these I believe.  However, it may be best to try a different power tube first and then see where you end up.  A pretty good, not the best though, NOS 12au7 are the RCA clear tops, which should sound much better than the Made in China stamped stock tubes.
  
 I hope this helps, but let us know.  Also, fellow headfier mhamel has quite a few new production variants and was planning on letting us know how each ultimately turned out, so stay tuned!
  
 JK-47,
  
 It was probably the best idea to just return them, even if the price was really good, as the vast variation may indicate that there is an issue with one of the tubes.  Do you happen to have a Tube Manual, that is one that lists the readings for each tube at nominal value?  G.E.'s manual is considered the best and most comprehensive, but some may also include these voltages, along with the GM.  Anyway, I'm sure another good deal will pop up at some point, patience is everything, and so is getting what you expect, which in this case was a matched pair.
  
 I like the system, thanks for sharing!  Many of us here can attest that this audio stuff is really a journey, not just a destination, and most of us started out with pretty basic systems that we have added to or tweaked over the years.  No need to rush in and spend thousands upon thousands, unless you are confident in what you ultimately want and have had exposure to everything you end up buying (in a perfect world, right!).  It is also always hard to gauge someones ears and preferences, but even a great set of ears can usually be able to discern differences in a lower resolution system, at least in general.  The source and the end, in my opinion, are the most important, so starting with a high quality format, fed to a quality DAC, and ultimately to a nice pair of speakers/cans is very important.  Not that amplifiers are not important, as we have all experienced with the Elekit, but they really build upon the source and then affect everything they feed; the old saying probably reigns true here though, garbage in, garbage out, no matter how good the amplifier.  Anyway, you have a fine system that should be giving you some really great sound!
  
 john57,
  
 The EL34's are a very nice sounding tube, however I would be reluctant to call them the most transparent.  All tubes add distortion in the 3rd and 4th harmonics, as they are often referred to as distortion tubes.  However, distortion in these harmonics is different than the 1st and/or 2nd, that we generally associated to distortion in sound, and to many make the music actually sound more organic and natural... similar to how a live album sounds compared to a tightly controlled studio album.  With that said, the EL34's do change the sound and add their own flavor.  I've found that while some of the EL34s have great resolution, generally the KT-66 and KT-88 varieties have been more pronounced, with more weight/body, and better low-end resolution.  So, it is really hard to say which of the tubes that the Elekit can use, and that I've tried, are the most transparent, as they all add a little bit of their own flavor, while taking away other qualities as well.  I know that's probably not really the answer you were looking for, but honestly the best way to find out is to use your own system/ears, experiment with different types, and see where the chips fall.


----------



## JK-47

Effusion,
  
 Thanks for the tube manual idea, I literally just bought a 1961 GE and a 1975 Sylvania from ebay after I read your post.
  
 The thing about the Maximatcher 2 is that is more of a buyers tube tester, the Gm readings for 6L6GC tubes are no where near what a Hickok tester (the ebay standard) will produce. The Maxi's fail threshold is 2200Gm, and most of my vintage 6L6GC tubes are barely over that  (2300-2700Gm). Even the stock Electro Harmonix 6L6's were only 2550Gm with 40-50hrs on them. Whether it be the real world plate voltage of 400V, this tester really has a fine line with 6L6 tubes, when I measured my KT88's and EL34's, they were almost 2000Gm over the minimum standard listed by Maxi. That's OK by me, I'd rather have a tough test than an easy one, but if I plan on selling tubes, a Hickock will be in the cards...


----------



## JK-47

Well... to my dismay one of my Philco 6189's is microphonic... I contacted the seller and he will send me a replacement, phew!
  
 As the Philips 7581A's continue to burn in, I'm liking them more and more !!! I'm glad I bought 4, for a great deal. They provide exceptional clarity, detail, dynamics, soundstage, and punch top to bottom. Mine were produced in 1985, and their lineage is from Sylvania 6L6GC STR387, and then the Sylvania/Philips 6L6GC STR415 (they 415's look pretty much identical). Which can be had for a lower price, but I haven't had a chance to audition them yet...
  
 One of my reference tracks is Dire Straits' 8min+ version of  "Money for Nothing". The Amperex Orange Globe 12AU7's and Philips 7581A's just put a huge smile on my face...


----------



## LingLing1337

Jk47, I just picked it up a couple days ago from a kid in denver. I had wanted to build a tu-879 for a while and then the 8200 when it came out. But this one was very well built and I stumbled across it on Craigslist so I went for it. Ive really been enjoying the music for the past couple days. the usb dac is even a decent placeholder while my Peachtree Decco is in for repairs yet again.

With the Peachtree in the chain as the DAC and preamp however the sound is incredible. Soundstage has opened up substantially compared to the integrated speaker amp on the Peachtree. The tubes really give my Paradigm Monitor 7 a sense of warmth, depth, and realism that was missing from the somewhat mediocre 40wpc Peachtree amp. Im excited to start rolling some power tubes when they arrive. I am going to stick with the psvane mkii 12au7 in the preamp position so ill be getting rid of a couple pairs of clear tops and a pair of bugle boys.

Ill try to listen to a bit more music on headphones too so i can post some impressions. All i own now are Hd700 and Grado Sr80i though. Also Ill post impressions of the new issue mullard vs stock once I get them in. Later on im getting some psvane mkii premium power tubes, kt88 and el34. On that note Greg70 if you want to email me its my username at gmail. 

Quick question, anyone been to the vacuum tube store in Denver? Is it a good resource for NOS tubes? I don't feel that comfortable dropping big $ on NOS on ebay.


----------



## Effusion

LingLing1337,
  
 Congrats on the purchase, it is really an incredible amplifier and once you start to experiment with different tubes, you'll be hooked... both line and sinker!  
	

	
	
		
		

		
			




  
 By vacuum store in Denver, I'm assuming that you are referring to Vacuum Tube Supplies, LLC, which if you are, is a really great place to go and check out.  Peter and Ellen are super nice folks, with a ton of experience from years and years of being in the business.  Peter is amazing and knows probably everything you would ever want to know about amplifiers/tubes.  I believe he is the "go to" guy for all Guitar Centers on the Front Range and is always swamped with tons of repairs; from Hi-Fi, to guitar amps, to vintage boutique amps, to everything in-between.  Ellen handles the sales/customers and is really passionate about tubes in general and happy customers.
  
 Now, they do have a ton of NOS tubes and many for sale, mostly on their eBay storefront Vacuum-Tube-Supplies, but I have inquired about various NOS tubes that work with the Elekit in the past and unfortunately they never seem to really have many available for purchase.  They told me that they never really get any of the NOS KT series in anymore, that they sometimes get NOS EL34s in, but they fly off the shelves within minutes, and they probably have some 6L6GCs available most of the time.  They are meticulous about their testing, using a really nice/accurate Hickok 539C, and their customer service is top-notch.  Only issue is getting what you are looking for, as unfortunately, the NOS tubes that work with the Elekit, power tubes in-particular, are so darn popular.  They may have some 12au7s and variants available though.
  
 Peter also designs equipment for their Hi-Fi company, Fletcher Haynes Audio; unfortunately their site seems to be down, but here is an article from Stereo Mojo.  They offer some really cool gear, including a completely passive pre-amp with a remote control (crazy!), that I'm seriously considering trying one out as it would really come in handy.  They also offer a really cool phono-preamp, that has a ton of adjustments, load and such, for just about everything (which I've found is absolutely essential to getting the best sound out of your stylus).  Anyway, check them out if you are interested, they also come often to RMAF, since they are already really close.
  
 If you're in the area, it's worth it to stop by to see what Ellen has in stock, otherwise most of their business is over the phone and Internet, with the bulk of their sales of tubes off eBay.  You never know, they may have some really nice NOS KT-88s in stock!  If you are interested in new production tubes at all, I highly recommend them as well, as they really take their time to test/match each pair they sell as well as working with suppliers to get the very best batches in stock.
  
 Happy Listening!


----------



## LingLing1337

Cool, thanks for the info effusion. That passive pre with a remote sounds really cool, ill have to check them out


----------



## Effusion

jk-47 said:


> Effusion,
> 
> Thanks for the tube manual idea, I literally just bought a 1961 GE and a 1975 Sylvania from ebay after I read your post.
> 
> The thing about the Maximatcher 2 is that is more of a buyers tube tester, the Gm readings for 6L6GC tubes are no where near what a Hickok tester (the ebay standard) will produce. The Maxi's fail threshold is 2200Gm, and most of my vintage 6L6GC tubes are barely over that  (2300-2700Gm). Even the stock Electro Harmonix 6L6's were only 2550Gm with 40-50hrs on them. Whether it be the real world plate voltage of 400V, this tester really has a fine line with 6L6 tubes, when I measured my KT88's and EL34's, they were almost 2000Gm over the minimum standard listed by Maxi. That's OK by me, I'd rather have a tough test than an easy one, but if I plan on selling tubes, a Hickock will be in the cards...


 
  
 Very interesting info on the Maximatcher 2, good to know.  I always assumed that the "real-world" voltage tests of these modern testers would be more accurate than the traditional GM tests, however I could see where this would create issues when even the pretty much brand new stock EH 6L6GC is so close to their minimum limit.  I wonder if there is any additional info regarding 6L6GCs and these testers out on the web.  Glad to hear that at least the KT-88s and EL34s have some headroom to their test, as at least a little variance to the limit is helpful when trying to establish a percentage, etc.  I hope the tube manuals prove to be useful, however many list the nominal values the tubes should be at when new, instead of a minimum.  Another option to consider to get a better idea and perhaps a baseline if their listed limits appear to be to high, would be to try a bogey tube, that is a tube that is used to calibrate different testers; look for ones that have gone through the ropes and been verified to provide accurate results, usually between $30-$50.
  
 Is there any way, such as an option on the board, to test the tubes without the real-world voltage, that is similar to a traditional Hickok and other brand's test?
  
 I'm very intrigued in regards to the Philips 7581A and I'll have to try to find a good price on a pair to try them out soon.  Have you had the chance to compare them to a NOS KT-66 at all?  It seems they may be even rarer than some of the smoked glass NOS KT-66s... at least the prices I've seen would suggest that.
  
 Keep the impressions coming!


----------



## JK-47

Effusion,
  
 After some hunting and reading on the internet, one fellow with a MaxiMatcher said he lowered the Bias Voltage from the suggested -48V to -36V when testing 6L6 tubes. I tried it, and sure enough the Gm reading are very close to Hickock Gm readings!!! The current readings (mA) are also very close to Hickock current readings (for the few that have set up their Hickock to do so) leading me to believe this is the way to go when comparing Maxi (+/-1.5%)  readings with Hickock's(+/-10% generally). I'm quite happy with this discovery, and it falls in line with the tolerances of each tester's results (so far subtracting 10% from the Hickock results are almost bang on when the Maxi is set at the -36 bias voltage).
  
 I'm going to start shopping for a good deal on the Sylvania/Philips 6L6GC STR415's so I can compare to the virtually identical looking Philips 7518A, I paid $230 shipped for the quad of Philips 7581A's. Generally I have seen them listed for $150-$200 a pair. I paid $50 for the pair of GE 7581A's (they look identical to the GE 6L6GC's) I sent back, I have seen them for a lot more $$$ than that (and it hurt to see the current so out of wack, and return them). Philips bought Sylvania's tube production in approximately 1980 and continued using the same plant for tubes...
  
 I haven't tried a set of old stock KT66's yet, but will start to look... Your tube recommendation are bang on, and I hold all of your opinions in high regard.
  
 I see in your signature you have a Technics SL-1200MkII (RIP) ... Oh how I miss mine and all my Vinyl...
  
 This post was powered by the TRON Legacy OST and a bottle of Buffalo Trace... oh, and spell check..lol


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## Effusion

Very glad to hear that lowering the bias voltage of the Maximatcher a bit allows for better readings, at least closer to Hickok, with the 6L6GC tubes.  Nice discovery and thanks for sharing!
  
 I've tried both a pair of clear glass NOS GEC KT-66 as well as a pair of NOS Genalex Smoked Glass KT-66 and have really enjoyed both of them.  I've found that the Genalex is generally fuller in sound overall, having more weight/slam to the notes with a slightly richer tone, but both are really nice sounding.  Fellow headfier bixby also agreed with these impressions when we auditioned the Elekit in his system with both my HD650s as well as his Mad Dogs, and while he preferred both of these pairs to the other power tubes we tried, he also favored the smoked glass overall.  Both pairs test right at NOS levels and are matched by date/factory codes, and I believe the smoked glass are the older of the two versions.  Definitely recommended, especially since you also have a modded pair of Fostex T50RPs; they really made bixby's Mad Dogs sing in his system, but shop around to try to get a good price as they can go quite high.  Also, if you can, try to get identical date stamp codes if possible, or at least very similar; a lot of sellers are selling mixed production pairs and I've been told recently that a lot of retooling was done in the early years in regards to some of the Genalex/GEC factories, even differences between the production lines in the same factory.  Although I'm not really sure how much, if any, difference it ultimately makes in discernible sound quality, it is always best for resale, that is if you need to at some point part with them.  I would be very interested in your impressions of them, compared to the 7518A and other variants you have (great job on those prices by the way).
  
 Yup, I also love the SL-1200MkII, the 1200's are the best turntable ever made in my opinion.  I think Panasonic/Technics was just crazy for discontinuing the 1200 line... I mean, it's the original "wheel-of-steel" and are probably the best known and built turntables of all time, at least for the money.  I haven't checked in a while, but shortly after 2010 the remaining new stock started to dwindle to almost nothing and due to their sudden announcement of the discontinuation, prices for used ones, that were even pretty beat up, went through the roof!  Folks were buying them up like crazy, and at crazy prices.  I bought mine new way back in about '96 for $375 and is still in mint condition; I still have all the original packaging and even the receipt!  Talk about an investment, I've seen them go for up to $2,000 used, crazy!  Although I'm really not planning to ever sell, nor stop buying vinyl anytime soon... there is just something about the sound of vinyl.  Crazy to think that vinyl was almost dead until recently, at least for newer production runs, but the funny thing is that mp3/flac really ended up only killing CDs in many ways, and at the same time creating more of a need/demand for the organic sounding, many times artfully packaged, vinyl record market.  Plus, many artists now offer free downloads in mp3/flac/wav when you purchase the vinyl version... very cool!
  
 Thanks for your vote of confidence on the tube recommendations; always very nice to have the reassurance that one's own impressions are not completely straying folks away or misleading.  I'm really just glad that I've hopefully been able to help others get closer to their own state of audio bliss with this amplifier, but at the end of the day, the real thanks has to go to Mr. Fujita, Victor, and all the folks at Elekit for making it possible.


----------



## Mr Chance

Effusion,
  
 thank you for your reply and your suggestions. I e-mailed Emi at Elikit and I got the answer that KT77 and KT99 both work fine with the amp. Maybe you could edit your original post with that info so that it is documented where people easily could find it?
 I went ahead and ordered this:
  

  
 *Genalex Gold Lion KT77, TAD 12AU7WA and Mundorf MCap Aluminium Oil capacitors*
  
  
 It will be my weekend project to try it out since I'm home alone without the wife 
 Does anyone no if the recommendation about letting the amp "rest" for ten minutes before opening it up also applies to changing tubes?


----------



## JK-47

mr chance said:


> Effusion,
> 
> thank you for your reply and your suggestions. I e-mailed Emi at Elikit and I got the answer that KT77 and KT99 both work fine with the amp. Maybe you could edit your original post with that info so that it is documented where people easily could find it?
> I went ahead and ordered this:
> ...


 
 I think the 10min wait would be a good idea between tube changes (I wait at least 10min myself, as well as unplugging the amp from the power outlet). Not only are the tubes hot to the touch, it gives any voltage left over in the circuits a chance to dissipate. Elekit or Victor would be the best people to confirm this though.


----------



## Effusion

mr chance said:


> Effusion,
> 
> thank you for your reply and your suggestions. I e-mailed Emi at Elikit and I got the answer that KT77 and KT99 both work fine with the amp. Maybe you could edit your original post with that info so that it is documented where people easily could find it?
> I went ahead and ordered this:
> ...


 
  
 Thanks for following up with Elekit and letting us all know, I've gone ahead and added both the KT77 and KT99 variants to the original post.
  
 As far as letting the amp cool between tube changes, 10 min. might be a bit overkill, but as JK-47 indicated, it is best to wait a least a few minutes until the voltage dissipates.  Definitely don't remove the tubes while they are still glowing though, but I would say at least 2-3 min. wait after shut down should do the trick; I've never had a problem waiting only this long, even when switching types.  Also, as JK-47 noted, the tubes can get very hot, especially the power tubes, so be careful.  I use a small soft rag so I don't burn myself, as even with a 10 min. cool down, if you had the tubes running for at least 15 min. or so they'll still be quite hot, however this does depend on the actual type of tube.  Also, place them somewhere that can handle the heat, like a towel, instead of anything wood, that might leave a burn mark, or plastic, which can melt onto the glass.  Although it is impossible to not let the tubes get hot, other than heat, tubes dislike being turned on and off the most, which over time can shorten their life; no real need to worry too much about that though, just remember to have fun when you roll!
  
 In addition, it is always best to let the tubes warm-up a bit before playing music through them.  Generally a 30 second warm-up is sufficient enough, but it takes at least 5-10 min. until they sound the best.  As you probably know and can tell, this can make the act of auditioning different tubes a little harder.


----------



## LingLing1337

I recieved my el34 and rolled them in today. Im not familiar with tube amps so I did not know this would change the sound so drastically. The new production mullard el34 are better than the stock 6l6eh all around, except maybe if youre a bass head. Bass is tighter and more controlled, and reduced by quite a bit as well. Not to say the el34 are lean, more that the EH are bloated. Mids as others have said are magical. For the price I am thoroughly impressed. Soundstage has been expanded on all axes and is much more precise. Highs are smoother and again less pronounced than the EH. I feel like the Mullard are a more balanced tube with a focus on the midrange. Overall this is a tube I could live with every day if I had to. But paypal gives me too much 0% 6 month financing for that so its back to ebay for more tubes!


----------



## Greg70

lingling1337 said:


> I recieved my el34 and rolled them in today. Im not familiar with tube amps so I did not know this would change the sound so drastically. The new production mullard el34 are better than the stock 6l6eh all around, except maybe if youre a bass head. Bass is tighter and more controlled, and reduced by quite a bit as well. Not to say the el34 are lean, more that the EH are bloated. Mids as others have said are magical. For the price I am thoroughly impressed. Soundstage has been expanded on all axes and is much more precise. Highs are smoother and again less pronounced than the EH. I feel like the Mullard are a more balanced tube with a focus on the midrange. Overall this is a tube I could live with every day if I had to. But paypal gives me too much 0% 6 month financing for that so its back to ebay for more tubes!


 

 Very well stated and it certainly reflects  my impressions when I first tried EL34s LingLing1337.
  
 For some reason I had thought that the EL34 wasn't really a great audio tube , and I didn't expect to like them.. but they made my Elekit and Grado combo so much nicer in all areas.
 I assumed at the time that it was just a synergy with the Grado GS1000i.


----------



## JK-47

lingling1337 said:


> I recieved my el34 and rolled them in today. Im not familiar with tube amps so I did not know this would change the sound so drastically. The new production mullard el34 are better than the stock 6l6eh all around, except maybe if youre a bass head. Bass is tighter and more controlled, and reduced by quite a bit as well. Not to say the el34 are lean, more that the EH are bloated. Mids as others have said are magical. For the price I am thoroughly impressed. Soundstage has been expanded on all axes and is much more precise. Highs are smoother and again less pronounced than the EH. I feel like the Mullard are a more balanced tube with a focus on the midrange. Overall this is a tube I could live with every day if I had to. But paypal gives me too much 0% 6 month financing for that so its back to ebay for more tubes!


 
  
 Welcome to the cult of tubes...LOL


----------



## Mr Chance

"When I turn the amp on I first get sound in the left channel and after about 2 seconds the right channel comes to life. When I turn it of the same thing happens, the right channel fades out first and then the left. Is this normal?"
  
 That was a question I e-mailed Elekit and then I got the answer:
  
 "Please try to switch the right and left tubes. If the symptom switches as well, then it is due to the individual difference of tubes. Such difference, such as 2 seconds of time lag, is within a normal range."
  
 So I did as she said and the right channel started up first. The odd thing though is that even after the switch the right channel faded out first, so that stayed the same.
 Now after having changed to the KT77 and the 12AU7WA the startup takes a lot longer (the KT77s aparently need more time to get going) and I have noticed that if I put the volume to 0 and slooooowly turns it up the right channel starts up first.
  
 I have changed all the tubes around and the "problem" stays exactly the same. It's not really that big of a problem because when at 1/4 of normal listening level it's impossible to hear a difference between the to channels. But I'm curios about what is causing this. Any suggestions?


----------



## john57

It just could be a channel imbalance in the pot when starting from zero. You stated that after 1/4 of rotating of the pot it becomes normal. That is typical of many analog pots.


----------



## mhamel

jk-47 said:


> Welcome to the cult of tubes...LOL


 
  
 No truer words have been spoken... once it starts there is no end to tube rolling, if not with this amp then with the next tubed thing that comes along.


----------



## LingLing1337

Ill definitely keep my impressions updated in this thread. The grado synergy is fantastic with the el34 and sr80i. I want to get a couple more el34 varieties, then start with some 6l6gc.


----------



## Mr Chance

john57 said:


> It just could be a channel imbalance in the pot when starting from zero. You stated that after 1/4 of rotating of the pot it becomes normal. That is typical of many analog pots.


 

 Not 1/4 rotating of the knob, that would render me deaf, 1/4 of normal listening level 
 About 8 o'clock is about as high I can go with my AT-W5000 (50 Ohm).
 Thank you john57 for the answer!


----------



## Mr Chance

So I changed the capacitors and voilà, the problem I described earlier disappeared. Now left and right channels starts at the same level. Im going to let the new capacitors run for a couple of hours and then I'll give them a listening.


----------



## JK-47

mr chance said:


> So I changed the capacitors and voilà, the problem I described earlier disappeared. Now left and right channels starts at the same level. Im going to let the new capacitors run for a couple of hours and then I'll give them a listening.


 
  
 Did Elekit recommend changing the capacitors?
  
 Good to hear it's working proper again!!


----------



## Mr Chance

JK-47,
  
 no I never reported that part of the problem to them. I changed them simply because I was curious.


----------



## Effusion

lingling1337 said:


> I recieved my el34 and rolled them in today. Im not familiar with tube amps so I did not know this would change the sound so drastically. The new production mullard el34 are better than the stock 6l6eh all around, except maybe if youre a bass head. Bass is tighter and more controlled, and reduced by quite a bit as well. Not to say the el34 are lean, more that the EH are bloated. Mids as others have said are magical. For the price I am thoroughly impressed. Soundstage has been expanded on all axes and is much more precise. Highs are smoother and again less pronounced than the EH. I feel like the Mullard are a more balanced tube with a focus on the midrange. Overall this is a tube I could live with every day if I had to. But paypal gives me too much 0% 6 month financing for that so its back to ebay for more tubes!


 
  
 Great impressions, my own impressions are very similar for the NOS Mullard versions.  I also actually find it very intriguing that they are so similar, so I'm going to have to try a new production version soon.  Although I haven't tried one yet, I'm guessing that you may find the NOS versions to have a bit more resolution, with overall better finesse, so it may be worthwhile to try a pair.  If you are interested in trying out a pair, to save money look for re-brands, as they were common for this type/manufacturer.  You can tell that they are Mullards if they have the Xf1 through Xf4 Mullard stamp towards the base.  This indicates that it is in fact, made by Mullard, and I also believe that those with these codes were made in the Blackburn factory, which many hold in high regard.  Mullards also tend to have halo or circle top getters, either in singles or pairs.  Below is a picture of this from Tubeworld, notice the faint codes stamped near the base:
  

  
 Other variants that have impressed me in their own way, have been the NOS Tesla EL34s, especially the "blue glass", the Amperex, Siemens, and the Telefunken.  While the alternatives may not have as nice or as thick of a mid-range as the Mullards, their top-end for the most part has great resolution and sparkle and aren't nearly as laid-back, however you might find them to be a little light in the low end when compared to the Mullards.  Not that the Mullards are really heavy down below, just more so in the lower mids and upper bass than most EL34s; I've found other types, such as the Telefunkens and Teslas, to have a little less low end impact, but in exchange for really great highs.  Really all depends on your system and the type of music for which one is better than the others; as long as you can go without all the bass and also a more warm/laid-back sound helps in your system, the EL34s are great tubes, especially for classical and acoustic music.
  
 I also agree in regards to the sock EH tubes, they are just a little too muddy/bloated across the entire spectrum and seem to just not have that "wow" factor really anywhere.
  
 Congrats on your entry to the tube rolling world!  Keep your impressions coming...


----------



## Mr Chance

So I spent the evening having a little amp-battle. Actually I was only going to test if the TU-8200 could drive my Monitor Audio GX100 but since the amp was standing on my other amp, Onkyo P3000R/M5000R, some comparisons had to be made.
  

  
 At first I was really amazed how great the TU-8200 sounded. Maybe it was because I never though it would be able to handle the 88dB speakers, in triode mode even, so my expectations wasn't that high. But the biggest problem was that one of the speakers was to close to the amp so the sound made the tube resonate causing microphonics. The KT77s I have seem to be very prone to this phenomena.
 I would say that I would be happy with the TU-8200 as an amp for my GX100s but I would change to UL-mode to give it some more power.
  
 When I changed to the Onkyo it sounded very much more relaxed (as it should considering it could drive pretty much anything you throw at it). If the TU-8200 had an edge in some way I might be that voices was a bit more exiting. With the Onkyo they were more neutral. Another thing I discovered was that the irDAC really is a step up from the internal DAC of the P3000R. So I guess I'll have to start saving to get another one. I really thought leaving the WUS-forum and coming here would be a good thing for my wallet...  
  
 Does anyone know if it is possible to measure the capacitors when they are mounted? Since I changed them It seems that I get more power to the left channel. The capacitors are +/- 5% so could that be the problem?


----------



## LingLing1337

Glad to hear more speaker impressions with the 8200, especially with lower sensitivity speakers. Funny that you say the tube amp is more exciting and lively than the solid state amp. Which do you prefer for the sound signature of the gx100?


----------



## Effusion

Mr Chance,
  
 Glad to hear that the Elekit is able to handle a 88 dB speaker load, even in Triode mode.  Do you have the amp set to a particular Ohm output setting?
  
 As far as microphonics, it can be difficult when using speakers, not so much a problem with headphones, unless you are really jamming!  You can always try some tube dampeners, many like Herbie's, but others are available as well, such as Music Hall and various homegrown DIY.  You may find that not all tubes are severely microphonic as others, even those of the same type/manufacture will vary.
  
 Let us know how things progress in your comparisons, either with different tube changes as well as additional burn-in time on the Elekit.


----------



## Mr Chance

> Does anyone know if it is possible to measure the capacitors when they are mounted? Since I changed them It seems that I get more power to the left channel. The capacitors are +/- 5% so could that be the problem?


 
  
 I'm so glad I can hide behind an alias when I tell you that the problem was that I had left the left channel in pentod mode and only shifted the right one back to triode after having tried out the diffrent settings.


----------



## john57

I was a bit skeptical when you change the capacitors that fixed the channel imbalance unless there was a cold solder joint. Capacitors tolerance have very little to do with channel imbalance issues.


----------



## LingLing1337

I have a review of my new psvane tubed but I cant post it... I swear this is the only forum that gives me so many problems.


----------



## LingLing1337

Got my psvane 12au7 mkii premium pair in the mail... I really didnt expect a signal tube to make such a dramatic difference. With this tube detail is significantly improved. Soundstage placement is more accurate. Leading edge and decay are more palpable leading to a much greater sense of realism. I feel like the psvane does not add any coloration but rather lets the power tube really shine. For example I can now appreciate the smooth, organic sound of the Mullard el34 more easily. 

My current input tube rankings are as follows

1. Psvane 12au7 mkii ($70 shipped, ebay seller may accept a lower offer) "wire with gain" sound, detailed, fast and holographic without beinf bright
2. Amperex Bugle boy 12au7 ($40 shipped) warm, full tube sound. Most bass impact and depth of the input tubes ive tried, at the expense of speed.
3. RCA clear top 12au7 ($20 shipped) improvement over stock but not very noticeable compared to the Amperex or especially the PSvane. More resolution and bass control than the stock Chinese tube but you will have to listen for it.

Ill start trying different families and makes of power tubes now. PSvane seems like a promising place to start.


----------



## LingLing1337

Double post


----------



## Effusion

Thanks for sharing your impressions!
  
 I'm beginning to think that I'm going to have to try out the Psvane 12au7s soon!  I also agree with both your impressions of the Amperex and RCA; it seems like the RCA clear tops are starting to go for more money lately, as I purschased a matched pair, out of several dozen, right after I bought the Elekit and paid ~7.50 shipped per pair.  I agree though, it should only be an option if other 12au7s feel just a little too much money at first, if to just get an idea of what the possibilities of tube rolling can do before laying down one's wallet!
  
 I'm excited to hear your other impressions on the power tubes, especially if you get the chance to compare some NOS versions against a pair of Psvane KT-88s!


----------



## JK-47

LingLing1337,
  
 Thanks for the tube impressions.
  
 I have a few tubes on the way and some more goodies, that will be waiting for me when I get back home from work in 2 weeks.
  
 I scored a pair of Amperex 7316's for a song, because they were mislabelled in the auction as 7313's (I hope they test strong and are as tightly matched as the seller claimed). A quad of Sylvania 5963's with gold pins (claimed to be tested at NOS levels). A smoking deal on a pair of Genelex smoked glass KT66's (same date code, and claimed tested at 90%) with a broken key way though (octal tube replacement key way adapter ordered to assure proper orientation in my amp). A 5A Staco Variac to make my Maxi-Tester reading consistent. A mint looking Hickok 533A from the original owner is also enroute, to help compare to ebay sellers tube readings.
  
 Effusion,
  
 The allure of vinyl has taken hold of me again... I have a Pro-Ject Debut Carbon, Schiit Mani preamp (maybe the Elekit TU-8500 is in the future...   http://www.vkmusic.ca/TU-8500.htm), and a whole whack of LP's and 12" and 7" singles.


----------



## vkung

Psvane KT-88 MKII  is one of the best KT88 tubes in the market.  
 TU-500 is designed to match TU-8200
 TU-8500 can use 12AT7 , 12AU7, ECC802,6201 and  GE 5965A (stock tube).
12AT7 has the lowest impedance with TU-8500
 This is the review from Doctor John
 http://cheaptubeaudio.blogspot.ca/2015/03/review-elekit-tu-8500-full-function_19.html
 I recommend to replace the stock OP-AMP NJR2068  with TI OPA 2227P


----------



## LingLing1337

I had been eyeing tu-8500 myself. As well as tu-8100 for a small desktop system.


----------



## JK-47

For a while I've been meaning to let  everyone know why I think when I changed my stock 12AU7's out for another pair, the improvement in sound was so dramatic. I tested the stock 12AU7's at apprx 2200/2200 and 2200/1600 Gm's. The 12AU7 triodes on the right channel's weren't even close to matching one another. None of my other 12AU7 family of tubes have triodes this far off from each other. I could be wrong, but that difference sticks out at me like a sore thumb.
  
 Any input would be welcome.


----------



## Effusion

JK-47,
  
 Sounds like you got some really great deals!  Let me know what you think of those KT-66s; no worries, seems like quite a few of the KT series, as well as just about every type that has a large pin (many are hollow), are also missing the guide pin because it snapped off at one time.  Just make sure you line everything up when installing the replacement adapter; if you want to make it permanent you can also use a heat resistant silicone sealant, preferably one that adheres to plastics well.  Just make sure you file down the contact pieces so they made a good adhesion, especially the adapter as they are usually very smooth.
  
 Nice purchase on the Hickok, I think you'll like that model.  What ultimately helped me decide was figuring that it would do everything I really need it to, with some added cool factors like the listening test/headphones, etc., all at a smaller footprint than some of the higher end, and priced models.  Even though it is still a little heavy, I feel comfortable enough to be fairly mobile with it when needed.
  
 Glad to hear about the vinyl re-surge!  There is just something about that sound... 
	

	
	
		
		

		
		
	


	



  
 I'm currently using a Monolithic Sound preamp and battery supply unit that is fed by my 1200.  The only real reason I'm using this unit is that it allows one to tweak the loading of the cartridge, among a few other things.  I've found that certain settings drastically changed the sound, even more than most tube changes, and ultimately decided on the following; 44db, 1k ohms, and 270pf for my Denon DL160.  Every cartridge and stylus is different, but the crazy thing was that at the most common default setting, that is used by most preamps, my Denon sounded the worst!!
  
 It all depends on the cartridge you're using, but for what's it's worth, there are some companies out there allowing this and more tweaks from the preamp unit.  A few off the top of my mind are units by Musical Surroundings and Fletcher-Haynes Audio; these units allow much more fine tuning of these adjustments than the Monolithic Sound.  I do believe that you can adjust this simply by putting different components in the path, however I'm far to much of a layperson on topic to know how to really accomplish it.  I do remember seeing a few charts somewhere that listed major cartridges/stylus ideal load settings... now, if I just could remember where I found them, as I do remember that it was fairly accurate in regards to my Denon (I ended up slightly different, I believe mostly do to the Elekit as well as my own preferences).  The TU-8500 looks really cool, and I bet it sounds great!  Also being able to use similar tube types as one's amplifier, does help.  Definitely keeping it on my radar!
  
 Keep letting us all know how the newly purchased types fair and how things continue to progress!
  
 EDIT:  In regards to your wondering about the stock Chinese 12au7s, you could be right.  While we strive for matched pairs, many over the years have come to conclusions that it is much more important for each section of a tube to be of similar emission, than between tubes/channels.  I'm not an expert, but we could probably say that this definitely wasn't helping any, however either is the make and materials of the actual tube, which does make a difference.  I guess the only real way to tell is to get another pair, with which you can make at least 1 perfectly matched pair and then compare the sound with the off tube.  Could be at least an interesting experiment...


----------



## JK-47

Got home late last night, and the tube rolling/testing started early this morning. Found a bunch of bad 6DJ8 tubes (for my Dad's Lyr 2). The Hickock 533A is near mint!!! Tested it with a 6L6 bogey tube, and it was dead on.
  
 Started off with the input tubes
  
 Amperex 7316: Exceptional soundstage and detail, with a slight bump in the lower mids. Very nice indeed, but very pricey ( I lucked out and got the pair for a song). I really like the "Amperex Sound". Very similar to my Amperex orange globes, but the 7316's do everything a little better (maybe not for triple the price though).
  
 Sylvania 5963 gold pins: Decent soundstage (not as big as either of the Amperex's or the Philco 6189's), not a whole lot going on in the low range, they sound very analytical/dry and accurate (flat frequency response). Not really that much fun
  
 Power tubes to be con't... just started listening to the NOS GEC KT66's, so far they are simply awesome!!! Nice controlled low end, with gorgeous mids. Very very smooth and detailed. One tested very good, the other was only good (I must find more of these !!!)


----------



## JK-47

Power Tubes
  
  
 NOS Genelex KT66: Buy them now, or I will. Start hoarding these treasures if you can afford to. A real treat to listen too, simply amazing. Spectacular detail, new layers of sound will smoothly and effortlessly be unleashed upon you if you choose to let these reside in the TU-8200's sockets. A perfect blend of GE 6L6GC (warm low and mid, and Philips 7581A (tight, punchy, and controlled). The only possible downside is if you really start to crank up the tunes and put power down, they start to get a little loose. The Philips 7581A's excel at being driven hard, really hard, but at the cost of lost warmth.
  
 RCA 7581A: A relabeled GE 7581A (GE's etched dot code and font is clearly visible), basically a late 60's/ early 70's GE 6L6GC tall bottle from what I can tell. I prefer the earlier short bottle GE's, I find them slightly less bloated and more defined. Overall a super value if you can find them on the cheap...


----------



## JK-47

Just a quick update on the Tube Manuals I purchased (1961 GE and 1975 Sylvania). I find the Sylvania to be more informative, not just because it's newer. It has a lot more info; European equivalent, Industrial equivalent, Aviation Equivalent, a table of contents to quickly find what page the tube in question is on, and a quick reference section as well.


----------



## Effusion

JK-47,
  
 Glad to hear the Hickok tester is working for you, I really like that model for many reasons and it will allow you to better check the various types you end up purchasing.  I'll have to try to pick up a Sylvania manual in the near future as well, I do have an RCA, but I found the GE to be a bit better than it; thanks for the Sylvania suggestion!
  
 As always, thanks again for all your tube impressions!  They are very helpful to others who are contemplating on branching out and away from the stock set.  You've also tried several variants that I have not had the pleasure of hearing yet, so they have been very helpful to me as I consider new/different types to try.  I'll admit though, I've slowed down quite a bit with my tube purchases as of late, but I'm getting that itch again!  
	

	
	
		
		

		
			




  
 I agree, the NOS KT66s are simply amazing tubes, some of the best, if not the best, power tube I've tried in the Elekit thus far.  Deals can be found and several seem to popup from time to time, but they're not cheap; I haven't tried the NOS Genelex KT88s yet though, as they are said to be the very best, better than the KT66s.  The originals are just so rare and thus so very expensive... maybe one day I'll get lucky.
  
 Keep us up to date on how things progress!


----------



## LingLing1337

I have psvane premium kt88 on the way. Thought it would be appropriate to upgrade power tubes since I got new speakers (scansonic 2.5).


----------



## JK-47

I ended up not getting the Elekit TU-8500 preamp. I contacted Elekit, asking them for specs on the phono portion (specifically the capacitance). They responded by asking why I needed to know, and that they wouldn't disclose the specs for the phono portion. I told them my cartridge required a capacitance of 150-300pF and I was interested in purchasing the TU-8500, but would not if I didn't know the capacitance. They would only tell me that the TU-8500 would not be recommended for any cartridge with those requirements. I was some what disappointed by the whole email exchange. I ended up buying a Pro-Ject Tube Box S phono preamp, and it has 12AX7 tubes to roll!!! I will pick it up when I get off work in 10 days.
  
 I sent the Hickok 533A to Roger Kennedy for a Refurb/Calibration, as the power tubes were reading OK, but any 9 pin tube would read really high.


----------



## LingLing1337

Damn JK what a pain. Maybe if you had contacted Vkung he couldve been more help. The language barrier can be tough sometimes.


----------



## JK-47

Oh well, it doesn't really bother me too much. The TU-8500 is more of a preamp with multi-inputs (which I don't really need). A phono preamp with more adjustments is what I really need, to be able to tune to any future cartridge upgrades...
  
 There wasn't an issue with the language barrier, and Elekit was polite about everything. I have been to Japan many times in the last 15 years and my best friend lives there. It's just a different culture, and everything isn't always clearly defined... So no hard feelings.
  
 Let us know how the PSvane KT88's sound when you get them.
  
 I came across an interesting review of our TU-8200, and the fellow takes multiple measurements during his lengthly detailed review. The Elekit holds its own, and actually beats a McIntosh MC275 in one test!!! One interesting result was the level of distortion was lower when the amp was set to the 4ohm output setting and run to a 8ohm speaker vs the 8ohm setting to a 8ohm speaker!!! Very very fascinating  ...
  
 http://www.kenrockwell.com/audio/elekit/tu-8200.htm


----------



## LingLing1337

The high praise for the 8200 as a speaker amp (comparable to a MC240??) makes me even more eager to build a tu8233.


----------



## JK-47

Actually it's compared to the MC275...


----------



## LingLing1337

Actually, poindexter, its compared to both


----------



## JK-47

lingling1337 said:


> Actually, poindexter, its compared to both





Touche ,lol...you almost got me there
, but it appears you have also made the same oversite, Pointdexter


----------



## Haidar

Has anyone compared the Elekit with Leben headphone amps?
 I'm wondering about the differences in their sound (as headphone amps).


----------



## LingLing1337

It seems hard enough to find anyone who has taken the time to build one of these world class amps, let alone compare it to many other amps. But if someone wants to send me a Leben I'd be happy to do a comparo


----------



## Currawong

Hmm, I might have to take the HD800s, Ethers and HE10000s 'round to the Elekit factory sometime.


----------



## JK-47

currawong said:


> Hmm, I might have to take the HD800s, Ethers and HE10000s 'round to the Elekit factory sometime.


 
  
 Wow, that's quite the All Star line up


----------



## LingLing1337

Psvane kt88s arrived in the next city over today, gotta wait til Monday to get them! I wouldnt call my power tubes the "bottleneck" (get it?) in my system but the Mullards are definitely the lowest grade equipment in the signal path.


----------



## JK-47

lingling1337 said:


> Psvane kt88s arrived in the next city over today, gotta wait til Monday to get them! I wouldnt call my power tubes the "bottleneck" (get it?) in my system but the Mullards are definitely the lowest grade equipment in the signal path.


 

 I'm eager to hear your take on the New Tubes...


----------



## catcherfly

jk-47 said:


> One interesting result was the level of distortion was lower when the amp was set to the 4ohm output setting and run to a 8ohm speaker vs the 8ohm setting to a 8ohm speaker!!! Very very fascinating  ...



Is there any danger of damaging the amp listening to 8ohm speakers at the 4ohm setting?


----------



## LingLing1337

No, theres no danger. the way I understand it is, you can run 4ohm amp to 8ohm speakers, but not 8 ohm amp to 4 ohm speakers.


----------



## JK-47

catcherfly said:


> Is there any danger of damaging the amp listening to 8ohm speakers at the 4ohm setting?


 
  
  


lingling1337 said:


> No, theres no danger. the way I understand it is, you can run 4ohm amp to 8ohm speakers, but not 8 ohm amp to 4 ohm speakers.


 
  
 I agree with LingLing1337


----------



## catcherfly

jk-47 said:


> I agree with LingLing1337




Ok, thanks. I'll give it a try!


----------



## LingLing1337

Just got the new tubes (psvane kt88 mkii premium matched pair). I will post detailed impressions later but they are simply a cut above the new production Mullards I was using. Soundstage width, depth, and placement is immediately improved. Timbre is so much more natural. Speed is incredible, the exact opposite of what I expected from the fat bottle KT88


----------



## JK-47

lingling1337 said:


> Just got the new tubes (psvane kt88 mkii premium matched pair). I will post detailed impressions later but they are simply a cut above the new production Mullards I was using. Soundstage width, depth, and placement is immediately improved. Timbre is so much more natural. Speed is incredible, the exact opposite of what I expected from the fat bottle KT88


 

 Any updates??? I've been tube rolling for the last several days trying different combinations of pre and power tubes together. I have the Amperex 7016 and Gold Lion Kt88's working very nicely together right now.


----------



## LingLing1337

that sounds like an awesome combo. I'll write some more about the PSvane tubes next week. they took the Elekit to such a different level, though, that it sounds more like a new amp than new tubes. So I need to start collecting more top tier tubes so I can compare the subtle differences


----------



## LingLing1337

Ok I've spent some more quality time with the PSVane. Highs are represented beautifully with a bit of "sparkle" without being bright at all. My speakers have a ribbon tweeter and theyre now resolving a lot more of the speed and clarity that they're capable of. The inner details of vocals and guitars really contribute to the lifelike sound. I do prefer to hear the band in the room rather than from monitors in the mixing booth, and thats exactly what these tubes give me. The unique tone of every instrument shines through. Bass is much more controlled compared to the Mullard new production el34. I was afraid I had issues with my room or speakers but the flabiness has been cleaned up considerably. 

Compared to the Miniwatt N3, the PSVane Elekit is much more resolving of fine details, places sound more accurately, and has more authority and extension across the frequency range.
 With that said, the N3 has a really nice tone that surprised me. I listened to it hooked up to my Scansonic for a couple days and didnt find myself enjoyjng the music any less. Very nice, classic tubey sound thats easy to listen to. 

I have compared the speaker section of the Elekit directly to the Miniwatt, a T-amp, and an IcePower amp in the $1500 range. I absolutely prefer the Elekit. The fact that it's marketed as a headphone amp shows me what an overachiever this amp is. As I said I hope to build a Elekit 300b speaker amp next. If anyone would be interested in buying a TU8200dx with tubes for a good deal please pm me!


----------



## lucidreamer

Has anyone compared Elekit TU-8000 DX to Fosgate Signature and to Woo Audio WA6-SE amps? I am considering either of those tube three to add to my collection and am not sure which one would be better choice to drive HE-560 in terms of sound quality and performance. Any recommendations?


----------



## LingLing1337

Just a quick pic nothing fancy


----------



## Effusion

jk-47 said:


> I ended up not getting the Elekit TU-8500 preamp. I contacted Elekit, asking them for specs on the phono portion (specifically the capacitance). They responded by asking why I needed to know, and that they wouldn't disclose the specs for the phono portion. I told them my cartridge required a capacitance of 150-300pF and I was interested in purchasing the TU-8500, but would not if I didn't know the capacitance. They would only tell me that the TU-8500 would not be recommended for any cartridge with those requirements. I was some what disappointed by the whole email exchange. I ended up buying a Pro-Ject Tube Box S phono preamp, and it has 12AX7 tubes to roll!!! I will pick it up when I get off work in 10 days.
> 
> I sent the Hickok 533A to Roger Kennedy for a Refurb/Calibration, as the power tubes were reading OK, but any 9 pin tube would read really high.


 
  
 Sorry to hear that about your cartridge and the TU-8500... it's a bummer that they don't make these preamps more adjustable.  As a side note, I remember back when I was researching adjustable load capacitance, etc. for proper cartridge matching, I found quite a few DIYers who were saying that they hooked up volume pots attached to some kind of internal attenuation and essentially made the load completely variable by use of the pot.  I really have no idea how to do it or specifics, etc., but I found it very interesting indeed... if one was so inclined.  Talk about fine tuning!  
	

	
	
		
		

		
		
	


	



  
 Have you received the Tube Box S yet?  Unfortunately, the 12AX7 are not the same specs as the 12AU7; trying to remember off the top of my head, but something is doubled in the X version.  That's not to say you absolutely can't use 12AU7s in your preamp, as some are designed to handle both, but better to check with Pro-Ject first to make sure you won't have any potential issues.  If I remember correctly, sometimes a circuit for the X can handle the U, if it is built correctly to, but generally not the other way around.  Would be better to check first, but just think if it does, you've already got some nice 12AU7s for the Elekit!
  
 Good idea on the Hickok, Roger is an amazing guy and I'm willing to bet he is the most knowledgeable person when it comes to Hickoks, even other testers, period.  Unfortunately do to his recent surgeries, repairing them has been more difficult than in the past... it's too bad as he is a really great guy who takes a lot of pride in his work.  I just hope his health has improved a little since I last spoke with him and that he is starting to feel a bit better.


----------



## JK-47

LingLing1337,
  
 Nice pic 
	

	
	
		
		

		
		
	


	



  
 Effusion,
  
 The Tube Box S was made a very noticeable improvement over the Schiit Mani... Smoother, richer, wider soundstage, and almost no background noise unless cranked way past 2 o'clock !!! I emailed Pro-Ject about replacing the tubes with the slightly lower gain but a touch higher in the heater current department 5751 tubes. They suggested I stick to 12AX7's only (12AX7 apprx 90 in the gain department vs 70 in the 5751's and 17 in the 12AU7's). I rolled out the stock made in China 12AX7's for some Canadian made Amperex 12AX7's, again the music took a turn in the right direction and opened up even further with more detail and clarity.
  
 Roger confirmed he received the Hickok at the end of April, and said it could be anywhere from 3-9 weeks before he gets a look at it, so I will wait a little longer before contacting him and asking for updates. He made it clear I would be looking at least several months before I sent it to him, and I get the impression he doesn't like to be pestered or rushed. I'm in no hurry to get it back, the Maxi's are doing just fine. I just want it calibrated properly by a professional.
  
 I have a TEAC UD-301 DAC on the way... So when I get home at the end of June, I will be having a Vinyl vs DSD showdown featuring Michael Jackson's "Thriller" album...lol


----------



## vkung

Hi JK-47
  


jk-47 said:


> I ended up not getting the Elekit TU-8500 preamp. I contacted Elekit, asking them for specs on the phono portion (specifically the capacitance). They responded by asking why I needed to know, and that they wouldn't disclose the specs for the phono portion. I told them my cartridge required a capacitance of 150-300pF and I was interested in purchasing the TU-8500, but would not if I didn't know the capacitance. They would only tell me that the TU-8500 would not be recommended for any cartridge with those requirements. I was some what disappointed by the whole email exchange. I ended up buying a Pro-Ject Tube Box S phono preamp, and it has 12AX7 tubes to roll!!! I will pick it up when I get off work in 10 days.
> 
> I sent the Hickok 533A to Roger Kennedy for a Refurb/Calibration, as the power tubes were reading OK, but any 9 pin tube would read really high.





  

 I will discuss with Mr Fujita about your questions..


----------



## JK-47

vkung said:


> Hi JK-47
> 
> 
> 
> I will discuss with Mr Fujita about your questions..


 
  
 Thanks Victor. It would really help potential buyers with turntables in their system.


----------



## vkung

Here is the loading table for TU-8500
  
There is no need to use 2 resistors for R1 and R3 . User can use just one resistor for R1. 
  
  

  
 Cartridge Loading
 MM (L/R)    
 MC
 R5 ,  R6
                          
 R1, R2       
 47Kohm
 47K
 100
 default
 500ohm
 500
 100
 　
 200ohm
 200
 100
 　
 100ohm
 100
 100
 　
 Remark
 No resistor for R3 and R4
 No change
 　

  
When you consider the capacitance,
You always need to take the wiring  into consideration.
Please check the SHURE site below.
  
http://cdn.shure.com/user_guide/upload/1049/us_pro_m92e_ug.pdf
  
Optimum Load: 47,000 ohms resistance in parallel with 200 to 300 picofarads capacitance per channel. Load resistance can be up to 70,000 ohms with almost no audible change in frequency response. Total capacitance includes both tone arm wiring and amplifier input circuit.
  
Also, for MC, there is no need to change the resistor.  Changing the resistor does not affect much.
  
  
If you need anything, please let me know.


----------



## JK-47

Thanks for the info Victor, but the TU-8500 capacitance is still a mystery....


----------



## vkung

hi JK-47
  
 If you look at Audio Research Reference Phono 10 or other expensive phono amps, they  won't tell you the capacitance too.  
 I trust Mr Fujita's design.


----------



## JK-47

vkung said:


> hi JK-47
> 
> If you look at Audio Research Reference Phono 10 or other expensive phono amps, they  won't tell you the capacitance too.
> I trust Mr Fujita's design.


 

  I don't doubt Mr. Fujita's designs, his Amps are awesome 
	

	
	
		
		

		
			




  
 I just wanted to be able to match my turntable cartridge, or future upgrades to the recomended values. My previous Schiit Mani had a capacitance of 100pF, and even with the wiring was borderline on the low end of the 150-300pF recommendation. More for piece of mind than anything else.
  
 I will definitely be adding another Elekit amp in the future...300B.....


----------



## vkung

I will try one more time to ask him to let us know the capacitance .


----------



## JK-47

vkung said:


> I will try one more time to ask him to let us know the capacitance .


 

 I think it's ok if he doesn't want to reveal the capacitance. His creations are excellent, and maybe that little bit of mystery adds to the magic


----------



## vkung

Mr.Fujita says there is no need to know the capacitance. He is guessing ....it is probably several pF at most.


----------



## mhamel

jk-47 said:


> I don't doubt Mr. Fujita's designs, his Amps are awesome
> 
> I just wanted to be able to match my turntable cartridge, or future upgrades to the recomended values. My previous Schiit Mani had a capacitance of 100pF, and even with the wiring was borderline on the low end of the 150-300pF recommendation. More for piece of mind than anything else.
> 
> I will definitely be adding another Elekit amp in the future...300B.....




I'd love to see a version of that 300B amp with a headphone out. I was thinking of buying one and building an adapter when I bought the 8200 kit.


----------



## LingLing1337

Looks like the speakers im using are 88db sensitive @ 4ohm. The little tu8200 kicks ass but I'm going to get a powerful solid state to compare.


----------



## vkung

You need to compare the clarity..


----------



## lucidreamer

Hi everyone,
  
 I just got my new Elekit TU-8200DX tube ampflier kit (with upgrades) built last Friday after it arrived from VKMusic.ca. Victor shipped it on Monday and it just took 5 days travel from Vancouver, BC to Florida which was pretty quick. It took me around 12 hours from start to finish, since I wanted to make sure everything was right before soldering it to the board.
  
 Victor from VKMusic.ca is a fantastic person to deal with all the time, very supportive and enthusiastic about his audio stuff! I had a pleasure to talk to him on the phone a couple of times to discuss the possible upgrade options, some tube choices, and so on. When I sent him an email with some questions, he responded almost instantly which was not something you would get these days (unfortunately). I would highly recommend VKMusic to anyone (with some basic electronic DIY skills, of course) who is looking to build a great tube amplifier at a very competitive price but still weighs all the risks associated with doing it by oneself using a kit or buying a ready to plug product. Well, there are lots of great commercial tube amps on the market but, in my mind, this Elekit one has definite advantages over many of them that cost much more. Even by looking at its schematic topology and choices of parts proves it immediately. The Japanese quality is top-notch and the steps in the manual are perfectly detailed. The amp is pretty easy to take apart for upgrades and service, if needs arise, it has all the modular design with Molex connectors and does not require any soldering to take it apart completely.
  
 I was really surprised by how good it sounded even with the stock 6C6EH power tubes before any burn-in took place. The sound is very balanced and detailed, there is plenty of bass as well, that I was afraid to be lacking before, but I was mistaken. It is not bass heavy, rather very pronounced and reference-like, very dependent on the source quality too. I cannot comment on the stock tubes sound since I currently have only the stock ones, once I will get the upgraded tubes, I will be glad to compare them with these ones that came with the kit. However, those ones are sounding great to my ears as well.
  
 The aluminum volume knob has a little hole in it to insert a regular led light and some recessed area to store the wire for supplying the (+) voltage to the led after another 10k ohm resistors soldered to R62 leg. I think it looks cool to complement the amp with the lighted volume knob as well as making it practical to easily to adjust the volume at total darkness. It is super easy to do too.


----------



## JK-47

Welcome to the club lucidreamer!!!!
  
 Great mod on the volume knob 
	

	
	
		
		

		
		
	


	




 looks sweet.
  
 I saw a the same mod on a different Elekit amp on another forum, and it's nice to see it implemented on our amp.
  
 Keep us updated on the tube rolling


----------



## lucidreamer

jk-47 said:


> Welcome to the club lucidreamer!!!!
> 
> Great mod on the volume knob
> 
> ...


 
 Thanks JK-47! I am hooked on the tube sound already (actually from childhood) and will definitely post my thoughts on various tubes later on... I already have a pair of Psvane KT-88 and 12AU7-T MKII tubes on the way, but it may take a few days to arrive from overseas.
 Yes, the volume knob had a space for the light already and it was just perfect to fit a regular size led that I took out from a cheap flashligh toy that ran out of batteries and was abandoned by my son  Looks like he dropped the flashlight into water or something, since the wire leads had some corrosion on them. I used some electric liquid insulator paste to secure the led and prevent the light from leaking back into the amp box. Initially I put a 1.37k ohm resistor and it was super bright, almost turning a volume control into a headlight, which would be a overkill for its purposes and too annoying during nights. So I took the amp apart and replaced the resistor with a 10k  one which is perfect and should keep the light from burning out faster. Inside the light hole I put a small optical plastic rod machined from the piece of clear plastic from the external hard drive enclosure that had a drive failure lately. The plastic sent the light from the harddrive PCB to the front of the enclosure. After machining the tip to a round shape to fit in the hole it sticks out a little bit and looks better to me than just a simple empty hole with a light in it. I think any piece of clear or other colored acrylic should work just as well.
  

  
 Maybe worth mentioning something else...  those who plan to buy and assemble this amp should have decent soldering station in place with fine point soldering tips handy. There are some tiny pins to solder for multiconnectors to the board with their pins standing 1 millimeter apart!! I also bought the following great tool on Amazon to secure the PCB board and allow it to flip 360 degrees. It would be a royal pain to do it without it:
 http://www.amazon.com/gp/product/B00Q2TTQEE?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00
  
 A nice pair of breathable electronic gloves like this is nice too:
 http://www.amazon.com/gp/product/B00880BB9S?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00
  
 I used a 4%-silver bearing German-made quality solder everywhere too. Another type of solder that I used before already turned greyish, but this one is still shiny clean on the PCB after 15 years!!! It has a flux mixed into the lead and after completing the board - I ran a toothbrush soaked with alcohol to remove as much flux as possible. Not sure if flux has any effect on the sound quality, but it is just a good practice to make sure that no small soldering particles are loose after the work is done to prevent shorting the parts.
 The transformer sends 300 volts to the tubes, it is quite high voltage and should be taken seriously.


----------



## lucidreamer

I am just curious if it is normal that the whole metal chassis case getting pretty warm after a short while when the amp is running? I mean it is not too hot to the touch but is pretty warm let alone the tubes which are actually hot. I believe it should be normal, since the tubes emanate heat that is dissipated and evenly distributed by the metal case but I just wanted to double-check.
 When I first assembled the amp, I let it run for a few mins only to make sure there was nothing wrong with it, like excessive heat, smoke, etc. or the transformer making noises. Then I put the case on. I should have probably tested it for a hour at least without the case to make sure no parts get overheated or something (except the tubes, understandingly). In my experience, if something is not done right, it may still work ok, but some components may be overheated and burn out quickly.
  
 Thanks.


----------



## JK-47

lucidreamer said:


> I am just curious if it is normal that the whole metal chassis case getting pretty warm after a short while when the amp is running? I mean it is not too hot to the touch but is pretty warm let alone the tubes which are actually hot. I believe it should be normal, since the tubes emanate heat that is dissipated and evenly distributed by the metal case but I just wanted to double-check.
> When I first assembled the amp, I let it run for a few mins only to make sure there was nothing wrong with it, like excessive heat, smoke, etc. or the transformer making noises. Then I put the case on. I should have probably tested it for a hour at least without the case to make sure no parts get overheated or something (except the tubes, understandingly). In my experience, if something is not done right, it may still work ok, but some components may be overheated and burn out quickly.
> 
> Thanks.


 
  
 My Elekit get's fairly warm to the touch too...


----------



## lucidreamer

Thanks JK-47. I also figured it was pretty normal for tube gear to get that warm. I may also consider building a metal protector enclosure for tubes or some sort of tube guards to prevent touching the tubes by accident, with small kids running around, you never know.
  
 Another thing I am a little confused is whether I should use the stock power cord that has a lifted ground (green wire) or replace it with a regular 3-prong heavy duty (15A) power cord that I have in stock. I used the 3-prong and did not notice any hum or noise compared to the stock cable. However there are some reports online about this amp where switching to the 3-prong power cable added more noise/oscillations caused by the ground loop. Switching back to the stock cable fixed the issue:
  
 http://www.6moons.com/audioreviews2/elekit/2.html
  


> The power cord that comes with the Elekit is a two-prong plug with floated ground wire that looks identical to the one for the  *Triode TRK-3488*. I learnt my lesson last time where floating ground silenced hum. It took me no time to reconfirm that on the Elekit. I compliantly replaced the more expensive three-prong power cord with the humble-looking stock. 
  
 In the TU-8200DX manual it is recommended to attach the ground wire to the electric outlet if it does have a ground terminal on it. But here in the US all the 120v household outlets already have 3 prongs anyways. Why not replacing the stock one with the 3-prong cord then. Did anyone notice any issues after trying the 3-prong power cord by chance?


----------



## LingLing1337

I didnt notice any difference running with a 3 prong plug. Perhaps in Japan the plug standard is different?


----------



## lucidreamer

Right. There should be no perceivable sound quality difference, only possible humming or electric noise picked up by the ground loop but that is not the grounding issue but something else usually.
  
 I do not really understand why people shell out big $$$ to buy expensive power cables trying to improve the sound, but that is just my opinion....
  
 To check for that possible noise issue with grounded/non-grounded cables - I tried plugging in my sensitive IEM monitor headphones and did not notice any difference between the sound quality or noise level at all. Actually the NSR level of this amp is superb!!!! With IEM phones there is some background noise present which is normal because those phones are super sensitive and are loud at 7:30 o'clock where 7 is zero volume plus I hear noise through them with every single source anyways. When using my HE-560 it is black silence throughout the whole volume range which is fantastic for tube amps.
  
 I think the biggest concern with absence of grounding is safety since grounding the chassis reduces the risk of electrocution when a live wire (usually white wire) comes into contact with the metal chassis. If the chassis is grounded it should trigger the amp fuse or the breaker in the garage to go out, 100% about it, I need to check with the schematic again. But if not grounded, there is a potential that the chassis can become a current live conductor that can send a person's heart into a state of ventricular fibrillation pretty quick. Then the sound quality quickly becomes not that important  In my home country there was 220v current and no ground pin in the plugs and there were lots of fatal electric accidents.


----------



## LingLing1337

Grado Rs1e are in the house so I am doing a lot more headphone listening. The Senns just didnt suit me. I will have a Little Dot I+, a highly regarded budget tube hybrid esp. for Grados, in for review and comparison tomorrow.


----------



## JK-47

lingling1337 said:


> Grado Rs1e are in the house so I am doing a lot more headphone listening. The Senns just didnt suit me. I will have a Little Dot I+, a highly regarded budget tube hybrid esp. for Grados, in for review and comparison tomorrow.


 

 I would have sold you my Little Dot I+ Hybrid if I knew you were looking for one... It has the Muse02 OpAmp, GE JAN tubes, and Voshkod Russian Rockets...


----------



## JK-47

I use the stock power cable, and left the green ground unplugged as per Victors instructions. Now I plug into a power conditioner, including the green ground (the conditioner has a ground post). I did not experience any hum or noise with or without the green ground hooked up.


----------



## Effusion

lucidreamer,
  
 I'm glad you're enjoying the Elekit!  Given a wee bit of time to burn-in and some additional tubes to roll, this amp can be astonishingly good.
  
 I 100% agree with you regarding Victor and it sounds like the build went well; now it's time to sit back and enjoy!  I think you'll find that with different types of tubes you can really tweak and fine tune the sound signature.  Thanks for sharing the photos/details on how to install the LED light on the volume control; I think I may have to do that mod in the near future, very cool!
  
 As far as heat goes, many tube amps can get really hot, especially around the sockets, but I have yet to have had any issues because of heat and I do tend to run them for long periods.  Compared to my other amps though, the Elekit does seem to get a bit hotter sometimes, especially with a KT88 or a 6550 and around/near the sockets.  After around 2 hours of use, right between the two 12au7 sockets is probably the hottest place on the case, including around the power tube sockets, which would second, but the rest of the case seems to be just warm.  I wonder if you could cut some slits into the case on both sides to allow some air flow in/out, without getting all the dust in, would help; many tube amps have them.  You could probably even install some kind of heatsink in different areas, but you would probably need to be extra careful in doing so.  Otherwise, as long as you don't confine it to a small space with something right above it, allow some air around it, and also keep it out of hot situations, like direct sunlight, it should be okay.  It would be interesting to temp the surface or even inside to really know for sure though.
  
 Interesting about the power cord, as I've actually been using an Iron Lung Jellyfish hospital grade cord for most of my time with this amp.  I'll have to spend some more time with the stock cord soon and report back.  Thanks!
  
 I hope you enjoy the Psvane combo, I've heard many great things.  Keep us up to date on your progress/findings, let us know if you have any questions, and welcome to the club!


----------



## Currawong

Japanese households usually don't have grounded sockets available, except for white goods, such as fridges, washing machine and aircon. Since those devices have parts that get wet, the grounding is most important.


----------



## LingLing1337

Lucid, if you love the tube sound, id suggest grabbing some NOS tubes as well... to me, the PSVane KT88 setup sounds like a good SS amp with an extra drop of honey. That is to say they colored the sound less than other tubes I tried.


----------



## lucidreamer

lingling1337 said:


> Lucid, if you love the tube sound, id suggest grabbing some NOS tubes as well... to me, the PSVane KT88 setup sounds like a good SS amp with an extra drop of honey. That is to say they colored the sound less than other tubes I tried.


 
 I may be well mistaken but with NOS and tubes in general - when you buy something and do not like the sound, does that mean you keep them or have to sell them privately?
 It just sounds like lots of money spent the wrong way if I need to keep tons of spare tubes in stock and only plug in those few that I like the most. Places like music123, wwbw, etc. should have no problem returning tubes, I think, but eBay and hi-fi end shops are not that happy to accept returns unless there is something wrong with them, of course. I would rather buy something that I am 99% sure that it will sound great and would not have a buyer's remorse later on.


----------



## lucidreamer

Sorry for asking so many questions as being fairly new to the tubes audio again after a long break (35+ years using solid state audio gear). What is the best preferred power tube mode for Elekit amp: Triode, UL or Pentode? 
 To me the Triode sounds more detailed and polite where the UL is more dynamic and has punchier bass. Since I mostly use the amp with my headphones - should I stick to Triode mode which has less power and less distortion or to UL mode. Thanks.


----------



## LingLing1337

I doubt youll find an NOS tube with a return policy, youd probably have to sell privately. Theyre definitely worth the risk though IME.
 PSVane Premium MKII are a good bet for high-end new production tubes. There is also a company out of Ukraine I believe, cant remember the name, making ultra high end new production tubes.
Power tube mode is totally up to you. My speakers are low sensitivity so kt88s in pentode/4ohm mode sound perfect. If I were running bookshelves I'd experiment with UL and triode. For highly sensitive speakers like horns I bet triode would sound great.
Headphone wise I will be able to compare pentode and triode output tonight on my Grado RS1e. The LD I+ gave the 8200 in triode an incredible run for the money, I was actually shocked at the results. Ill post more details later.


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## JK-47

lingling1337 said:


> I doubt youll find an NOS tube with a return policy, youd probably have to sell privately. Theyre definitely worth the risk though IME.
> PSVane Premium MKII are a good bet for high-end new production tubes. There is also a company out of Ukraine I believe, cant remember the name, making ultra high end new production tubes.
> Power tube mode is totally up to you. My speakers are low sensitivity so kt88s in pentode/4ohm mode sound perfect. If I were running bookshelves I'd experiment with UL and triode. For highly sensitive speakers like horns I bet triode would sound great.
> Headphone wise I will be able to compare pentode and triode output tonight on my Grado RS1e. The LD I+ gave the 8200 in triode an incredible run for the money, I was actually shocked at the results. Ill post more details later.


 

 I guess the LD I+ has a good synergy with your Grado's. With  Alpha Dogs and modded T50RP's, my LD I+ is not even in the same ballpark. My TU-8200DX has a huge advantage in detail, soundstage, and head room ( I have to almost max the volume on the LD I+ to equal 12 o' clock on my TU-8200DX in UL mode). I upgraded the LD I+ opamp to a Muse02 (big improvement over stock) and tried a few well regarded NOS tubes (again a large improvement over stock).
  
 My LD I+ will be up for sale when I get home next week if anyone is interested...


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## Effusion

lucidreamer and LingLing1337,
  
 I agree about taking the risk and have found that it's usually in ones best interest to try out a few different types, especially with this amplifier as the possible combinations are crazy and you might be surprised.  You are also correct about the resale, this is generally what one must do, so if you don't like the sound in your system, you might have to sell them yourself if the vendor is not willing to give a grace period or return.  This in turn generally requires the use of a good tester prior to sale, etc.  The only companies I've heard about that do offer returns have been making semi-expensive new production and in smaller batches, so I know that at least some do.  Does anyone know if Psvane allows returns, that is if you buy direct?  If so, there is a good chance that others would too, but probably for a price built-in and upfront as well as for an additional restock fee.
  
 I've found that especially with this amplifier because of all the choices, often just one combination doesn't always work and I enjoy swapping them out from time to time.  If you're able to roll quite a few different types, the combinations can seem endless in the Elekit.  In addition, if you own quite a few different types of headphones than one combination might not suffice for all; same with speakers, but sometimes you may find to a slightly lesser degree.
  
 lucidreamer, if you're worried about resale value if you don't care for them, if you bargain shop and set limits than you can oftentimes get pretty good deals.  If they are well regarded, even hanging on to them is in your best interest in the long and sometimes even short run.  Many of my 6sn7s I use for my other amps jumped way up in price recently and are worth quite a bit more than I paid five years ago.  All NOS varieties are a true limited resource to varying degrees and won't last forever, so if they work really well with audio, than they usually only go up in price over time.  However, you'll need to test them, sell them, and deliver them safely to a buyer, which can be a hassle, that is unless they've doubled in price.  
	

	
	
		
		

		
		
	


	



  
 Also, If you're interested in trying a few pairs of NOS or even some other types of new production (Psvane is probably the best new production right now though), let us all know.  Many of the posters here have tried quite a few different types in the Elekit, including myself.  I believe Psvane still makes other types that will work in the Elekit as well, such as the EL34 and 5881.  However I'm not too sure about Psvane's prices on these, but the good EL34 NOS can go for quite high, so it might be worth it to check them out, that is if you can return them to Psvane.  Selling the newer production, such as Psvane, may not reap the same scarcity rewards or at least break-even points as NOS often does; Psvane has come out with newer models/productions, so the older ones may drop in price over time, even if the manufacturing, but not design change and even for just in slightly used condition.


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## LingLing1337

The PSVane EL34 does look very interesting. I've been meaning to try it out. I do have some paypal credit...

Maybe we could get a tube swap going also? So once I get the el34 someone can try the kt88 without shelling out $150


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## Greg70

jk-47 said:


> I guess the LD I+ has a good synergy with your Grado's. With  Alpha Dogs and modded T50RP's, my LD I+ is not even in the same ballpark. My TU-8200DX has a huge advantage in detail, soundstage, and head room ( I have to almost max the volume on the LD I+ to equal 12 o' clock on my TU-8200DX in UL mode). I upgraded the LD I+ opamp to a Muse02 (big improvement over stock) and tried a few well regarded NOS tubes (again a large improvement over stock).
> 
> My LD I+ will be up for sale when I get home next week if anyone is interested...


 
 The LD1+ is a good little budget amp, but for me.. and with Grado GS1000i's, I also felt it was not even in the same ballpark as the Elekit in terms of detail and soundstage.
  
 In regards to the heat issues mentioned, any time you have tubes run at proper operating voltages and temps, there's no avoiding the amount of heat that will transfer into the amp via reflection and especially through the sockets.
 I do worry about the long term effect of heat on some of the components and on my amp I drilled some holes at the back and fitted a little vent on the bottom to allow for some circulation to carry a bit of the heat away, and also I put a piece of thermal barrier material on the underside of the top part of the case where the tubes sit.


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## LingLing1337

Class a tube amps and esp. Kt88s will put out quite a lot of heat.


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## Effusion

greg70 said:


> The LD1+ is a good little budget amp, but for me.. and with Grado GS1000i's, I also felt it was not even in the same ballpark as the Elekit in terms of detail and soundstage.
> 
> In regards to the heat issues mentioned, any time you have tubes run at proper operating voltages and temps, there's no avoiding the amount of heat that will transfer into the amp via reflection and especially through the sockets.
> I do worry about the long term effect of heat on some of the components and on my amp I drilled some holes at the back and fitted a little vent on the bottom to allow for some circulation to carry a bit of the heat away, and also I put a piece of thermal barrier material on the underside of the top part of the case where the tubes sit.


 
  
 Very cool modifications!  Thanks for sharing the pic!
  
 I would have to say that it's probably the best way to deal with the heat with this amplifier, at least that I can think of.  It would really be interesting to see the difference if we could take your modified unit versus another without, using similar types of tubes/time and check the temp both outside and inside the case.
  
 I agree and while we do want our components to heat up to a good operating level for the best sound quality, almost all tube amps, maybe with the exception of those that just use a miniature buffer DAC stage, probably get a little too hot for comfort.  I'm sure that over time/use this can lead to premature deterioration of some internal components, especially around the sockets.  It is what leads to the end of most tubes, which is primarily heat over time causing the filaments to break down, but they also do get really hot!
  
 Putting the mode switches on the bottom of the case looks great as well and probably functions better than on the top.  Great idea!


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## JK-47

Nice mods Greg70 !!!
  
 Any pics or directions on how you put the mode switches on the bottom? So obviously simple and effective at keeping the clean look of the amp, with the convenience of be able to quickly change the modes without dis-assembly.
  
 My hat's off to you  
	

	
	
		
		

		
		
	


	




 Very clever indeed.


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## lucidreamer

Yes, great mode switch and the vent cover modification, Greg70!!! I am seriously contemplating adding the two switches either at the back or at the bottom too. Probably at the back would be more practical, no need to lift the amp to change the settings, I like recessed button design like yours to avoid flipping them by accident when the power is on. Wonder is those wires should be shielded to reduce the possible issues with EMI.
  
 Also, any thoughts/recommendations of maybe installing a small silent fan similar to a computer one to the back plate that would draw the heat out from the case for cooling the internal components and to prolong their life. There is an open space between above the speaker taps. Drilling some vent holes on the sides with dust screen or cloth would be needed for proper air circulation. That would involve taking the whole amp apart though to drill those holes and install the fan(s), I guess. But thanks to the modular construction - it should be a relatively easy fix.
  
 One caveat to this is that a silent fan is a rare thing, I have not personally seen one yet. All of the motor fans still generate some sort of noise, especially after a couple of years when the bearings lose their lubrication and become looser. That would be annoying when listening to music through open design headphones. I bought a new cheap fanless ASUS laptop just because I hated that fan noise emanating from my i7 HP workstation laptop that was very audible between the songs. Even using a large external harddrive adds to the noise, the portable ones are the best and quietest.
  
 I did some research for fans and this one looks promising: http://www.amazon.com/dp/B00VQLYT18?psc=1 claiming noise level of 24 dBA which is somewhere in between "quiet bedroom and TV studio background" based on this noise chart:
  

*Sound sources (noise)
 Examples with distance*
  *   Sound pressure   
 Level **L**p dB SPL*
   Jet aircraft, 50 m away*140* Threshold of pain*130* Threshold of discomfort*120* Chainsaw, 1 m distance*110* Disco, 1 m from speaker*100* Diesel truck, 10 m away*90* Kerbside of busy road, 5 m*80* Vacuum cleaner, distance 1 m *70* Conversational speech, 1 m*60* Average home*50* Quiet library*40* Quiet bedroom at night*30* Background in TV studio*20* Rustling leaves in the distance*10* *Hearing threshold** 0*
  
 This one is pretty cool too and has a top aluminum plate to look nice: http://www.amazon.com/AC-Infinity-AI-CFS120BA-Single-Cabinet/dp/B009COQYA0/ref=sr_1_22?ie=UTF8&qid=1434734689&sr=8-22&keywords=120mm+fan+grill
  
 Probably installing the fan on top of the case may even be better if there is a good clearance above the amp. It will not require the complete disassembling, only taking off the top and the front cover to install the unit, plus drilling some holes.


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## Greg70

The switching isn't hard to do, but I do understand why Elekit don't recommend it.. because they're worried that someone might try to switch it "on the fly" and do some damage.
 It's important that it's only switched after the unit has been powered down for at least 10 minutes, which is why I put the switches on the bottom where no-one else would get to them. I also mounted the switches slightly recessed so that you have to use a fingernail to move it.
  
 I set mine up to only switch between Ultra Linear and Pentode, so I used this DPDT switch for it's high current rating which is overkill I'm sure when switched properly after power has dissipated, but a switch like this would never handle the 275V DC if it were switched while powered up:
http://au.rs-online.com/web/p/slide-switches/1759703/
  
 Each channel only needs one set of contacts, so you really only need a SPDT switch. A DPDT like the one I used could be wired to change both channels at once.
  
 If you want to switch all 3 modes, I believe you'll need something like this:
http://au.rs-online.com/web/p/toggle-switches/7109876/
  
 Wiring is simply a matter of connecting the "common" hole used for the jumper on the circuit board - that is, the hole directly connected to R17 or R18, to the common terminal on the switch.. and then the hole for the mode you want, to the corresponding terminal on the switch. I hope that makes sense.
  

  
 Lucidreamer
 I did consider a fan, but besides the audible noise, I was also worried about introducing electrical noise.. so I decided that convection was the safe bet.
 Theoretically the air can enter through the bottom under the boards, and flow either up and past the sockets and tubes, or over the power supply and out the back.


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## JK-47

Thanks Greg70


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## Effusion

Good idea about the fan, I like it.  However, Greg70 is correct, some oscillation noise would/could seep into the line of the Elekit, especially if the fan was hooked up to the amp's power source.  Similarly, if you're using a usb DAC that has it's own power source, cutting the power lead or buying a cable that only sends the data feed can even make a difference, if your DAC allows it (to test, use a cheap cord and cut the power lead).  I do like the one with the aluminum top plate, and you would be able to run it separately from the amps source, so that would help.  As long as the fan isn't creating too much of a magnetic field around the rotating fins, than it could be okay, if it turns out to be an issue, than you could just use the screen and take the fan out.  Probably best to use the power plug option as too many usb connections could cause issues, if their all on the same circuitry on the motherboard.  Crazy to think how noisy our computers can be, with fans and hard drives and all the such; it has prompted many to go towards more minimalistic silently passive cooled systems, such as the Mac Mini and various media servers.
  
 I did look up Psvane's return policy and it is pretty much a "sold as is" policy.  However some of the language in the link below indicates that exceptions can be made, but again only if they want to and probably only for how much extra they think you are willing to pay.
  
http://psvanetube.com/wordpress/psvane-tubes-warranty-return/
  
 As a result, I would have to say that it is probably not a good bet for others to offer a grace period as well.  Another shop, Upscale Audio, sells quite a few of the more reasonably priced new production, as well as some nice NOS 12au7s, but all at a bit of a cost more than others.  They also do not offer returns though.  However, they do "burn-in" their tubes by running them for I believe 48-72 hours before matching/shipping, so it is a good shop for quality new production.  Overall, unfortunately it would appear like ones only reasonable option is to sell them, if you find you don't care for them.
  
http://www.upscaleaudio.com/vacuum-tube-warranty-information/
  
 Greg70, thanks for info, very useful and probably the way I'll go down the road.  Right now I've been enjoying the Triode mode the most, but have switched back in forth and auditioned once before and I did enjoy the Ultra-linear mode at that time quite a bit.  I'll need to do some more auditioning of the two in the near future, especially once I start using my speakers again; however it is a bit difficult to do the switch, regardless of the 10 min. cool down, when you have to open the darn case.  It really makes this mod invaluable to auditioning as well as using multiple modes at different times.
  
 Great ideas and implementation!


----------



## lucidreamer

Has someone tried the Tube Amp Doctor (TAD) 6L6GC STR power tubes with Elekit TU8200 by chance? I just placed an order for a pair on Amazon for $50. They seem to be well regarded for great bass and overall dynamics and some people even rank them over =C= Winged 6L6GC that cost 2x than TAD ones. Once they arrive, I will give them a try and post my thoughts.
  
 I just got a pair of Psvane 12AU7 MKII and KT88 both in Grade A from Grant Fidelity this weekend. The 12AU7 MK2 do sound a little better and smoother than the stock 12AU7. As for KT88 - I actually liked them at first but then switched back to stock 6L6EH. The KT88 are extremely detailed, smooth and airy with deep bass and extended highs, very much like a solid state amplifier, however, I find them a little fatiguing after listening for awhile. They do have a reference like sterile, cold(ish) and fast sound quality that some people may enjoy, but to me they are missing some of that tube character and rich harmonics that even the 6L6EH stock tubes had. I would enjoy a little more warmer and mellifluous touch instead of fast attack maybe more. It could be my HE-560 planar headphones that I use or the lack of the recommended tube burn-in time. I am really doubtful that after the recommended 150-300 hours of burn-in they will be sounding richer and become sounding more tube-like, usually the initial character is there or not from the first few hours of breaking in the tube. I should also try them in UL mode just for the sake of testing. The Grant Fidelity claim burning in tubes before matching.
  
 Probably 6L6GC is what I am after in the long run.... I have not had a chance to listen to EL34 yet but based on the numerous reviews, this type of power tubes have a great rich midrange and are a little shy on bass and highs(supposedly), where 6L6GC is very well balanced overall. To my understanding EL34 is a great choice for headphones/speakers with pronounced bass/high notes, such as Grado or Beyer 990. But for more flat sounding headphones 6L6GC may be a better choice for more linear response.
  
 Any possible recommendations regarding the NOS or production 6L6GC tubes (besides TAD that I just purchased) that have that special magical, euphonious analogue tube sound. The stock 6L6EH sound pretty good to me already in terms of response and rich harmonics with less than 100 hours on them.
  
 Thanks everyone!


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## lucidreamer

Just found a good article elaborating on different flavors of 6L6 NOS tubes:
  
 http://www.audiotubes.com/6l6.htm
  
 Looks like the best ones are RCA black plate and next comes the GE 6L6 (bold blue):
  
*OK, SO TELL ME HOW THEY SOUND!!*
 Everybody keeps saying "you have to get (fill in the blank) brand of tubes or you are just not cool!" But do they sound good? The tube needs to sound good to your ears and deliver the kind of sound you are looking for, and nobody can tell you exactly which tube this may be! Here are some general observations:
  
350B, KT66, and EL37 types These are generally in a class by themselves. The 350B is the king of the 6L6 types with an incredible, palpable air and depth to the sound with razor sharp focus and dynamic power. It is not always compatible with all amps due to its different current draw and filament demands. The British NOS KT66 also rule in this category and are usually compatible with any 6L6GC circuit, ditto the EL37. Warm and rich, like most of the British tubes, again with nice power reserves. The EL37 only a little less powerful and getting harder to find every day. There is a USA KT66 called the 7581A and it is virtually the same as a 6L6GC, and are found mostly made by GE. Clean, detailed, airy, and powerful. The beige base version made for amps is superb and the rarest of this type. These types listed here are usually used in hi-fi applications, but the KT66 is sometimes favored for a British sound in guitar amps that call for a 6L6GC. There is a very nice KT66 version being made by Groove Tubes which sound similar to the Genalex, available in various hardness ratings. One of the best current production KT66 tubes available.
  
6L6GC types Most needed for guitar amps but these make a fine hi-fi tube in any amp calling for a KT66, 7581, or even 5881. *The blackplate RCA are the stars, and rightly so. They are rich, warm, detailed, creamy, and powerful. No other tube comes close except possibly the NOS GE 6L6GC.* The GE is a bit more linear from top to bottom and lacks some of the RCA richness, but we are still talking about the two best NOS tubes in this class! The GE is often much less costly, but this may change as they become scarce. Sylvania made this tube for many other brands. They are typically bright and sparkly, if a bit leaner in the bass. Usually the Sylvania made NOS tube is the winner when it comes to bargain performance. Do not overlook some of the current production tubes. The few that deserve attention are the JJ from the Slovak Republic, and the Winged C from SED, St. Petersburg, Russia. Both have near-NOS sonics at a much lower price. The 6L6GC type can substitute for any of the types below, but may require a bias adjustment or modification to operate at peak performance. Consult an amp tech whenever substituting tube types.
  
5881 and 6L6WGB types The Tung Sol is the most asked for tube here. The original 1950s and 1960s brown base tubes, often found made for the military (JTL5881 or JAN 6L6WGB used interchangeably) are smooth, detailed, and nearly as powerful as the 6L6GC types. They have great warmth yet balanced by smooth airy highs and wide dynamics. The GE and Sylvania are the next best thing and the choice if cost is a consideration. These brownbase tubes often have a silver getter spot on the side only, and both USA and Canada versions are equally excellent. These are brighter and leaner sounding, but often one-third less costly than the Tung Sol. Finally, the JAN Philips 6L6WGB with the green or blue labels are a super bargain but are getting hard to find. They were late 1970s made in the USA, and are somewhat bright sounding, but often priced far lower than either of the above types. This may change as stocks become depleated. Generally, guitar amps that call for a 6L6GC cannot use these tubes without bias circuit adjustments or even modifications. Consult an amp tech if you are unsure.
  
5932, 1614, 6L6Y, and other glass 6L6G/A/B types The metal 1614 and 6L6Y types enjoy a fine reputation in some McIntosh amps. The RCA are the ones most often requested, with fine dynamics, rich warmth, and detailed, airy highs. The 5932 glass military type can often be used in place of these (or any other except for the GC, KT66 or the 5881) and in this case the Sylvania is what is often found. They are powerful for their size, with a nice punchy and lively sound. Finally, the lower power 6L6 metal, 6L6GA and 6L6GB come in many NOS brands. The RCA is the warmest, the GE fairly balanced, and the Sylvania the brightest of these. The large G shapes are said to be the most musical. Like the 5881 types, these cannot be used in an amp calling for a 6L6GC or KT66 without at least bias adjustment or more likely, circuit modifications. Consult an amp tech if you are unsure.


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## JK-47

lucidreamer,
  
 Try I pair of vintage GE 6L6GC's, very nice for a reasonable price. The RCA "Black Pates"  are nice, but I don't think they justify the premium. Sylvania 6L6GC's (not the STR 387's or 415's) are a little drier sounding and sound more analytical, they almost sound like solid state (they also lack a little on the bottom end). I have Philips 7581A's (basically the miltary version of the Sylvania STR387/415 6L6GC)  in my amp quite often and enjoy them (very punchy, and accurate without sounding too analytical). The limited time I have had with various new production tubes always have left me wanting more out of them.


----------



## Greg70

lucidreamer
  
 Psvane make some of the best modern tubes you can get. They are accurate tubes with a good frequency response, and I guess they could be considered analytical and almost solid state if you're chasing a tubey tone.
  
 I wouldn't write off the EL34s. They are a very musical tube, and you might be surprised to find that you like them.
 I resisted them for a long time based on what I read, and then when I finally tried a pair I knew they were the ones for me in the Elekit.. admittedly with Grados.
 It might be worth trying a reasonably priced pair of modern EL34s just to see if the flavour appeals to you. I started with re-issue Mullards, and IMO they are similar in character to the fantastic NOS mullards and have maybe 80% or more of that tone so they're a good place to start to see if that tube suits you.
 In Ultra Linear mode they still have excellent bass response, although a little less than the 6L6 and KT-88 types.
  
 From the description of the sounds you're chasing, I think you might like Mullard or Amperex pre-amp tubes too 
  
 Good luck in your quest.


----------



## Effusion

Sorry to hear that you're not diggin the Psvane KT88s so much, they are highly regarded, however I have yet to actually be able to properly audition a pair myself.  I don't doubt that they may seem a little more solid state, as most new production tend to do, when compared to other types, even NOS.  There seems to be something with these NOS tubes; many find that they tend to give more bloom, sounding a bit more like a "tube" in general and compared to more recent batches.  This probably isn't always the case, but many have agreed so.
  
 JK-47's suggestion is a really good one.  I've also found that the GE 6L6GC can be worth the money, they are fairly inexpensive in comparison to others and sound pretty darn good.  I would have to say that the RCA Black Plate 6L6GCs I have tend to be a bit more solid state when compared to their GE counterparts, which can also be had much cheaper than the RCAs.  Below is a nice pair, similar test results, maybe not exactly matched on mutual conductance, but same date codes nonetheless; could be worth it:
  
http://www.ebay.com/itm/Two-GE-6L6-GC-vintage-tubes-test-great-see-pics-/171829439472?pt=LH_DefaultDomain_0&hash=item2801d52bf0
  
 Greg70's recommendation is also a very good one and may actually be close to what you're looking for.  The EL34s are nice sounding tubes and I feel tend to be more laid-back and bloomy, generally with great mid-range and air/soundstage.  I really like the Mullards, Teslas, Amperex, and Siemens... all have a slightly unique sound to each other.  An inexpensive, but highly regarded, newer production version is the SED Winged "C" EL34s.  Below is a nice pair that I think would give you at least an idea of what the EL34 can do:
  
 Better hurry if you want them though!
  
http://www.ebay.com/itm/SED-Winged-C-EL34-Tubes-Matched-Pair-/281726799211?pt=LH_DefaultDomain_0&hash=item419839cd6b
  
 The Mullards can be expensive, same with the Telefunken, but re-brands can be had at great prices!  Below is a pair of Valvo's, a Mullard re-brand, that look nice; notice the etchings in the glass near the base, the "xf" means it was made in the Blackburn factory in England, and I believe the 3 indicates the 3rd generation, made in the early '70s, so a little later production than others (generally less in-demand):
  
http://www.ebay.com/itm/2x-VALVO-MULLARD-EL34-6CA7-O-GETTER-XF3-TUBES-TESTED-STRONG-/291497006704?pt=LH_DefaultDomain_0&hash=item43de935670
  
 These Amperex "Bugle Boys" also look very nice; they have a different flavor than the Mullards, however mine aren't Bugle Boys though, so I can't say for sure... slightly different date codes, but test really good:
  
http://www.ebay.com/itm/2-NOS-NIB-Amperex-Bugle-Boy-EL34-6CA7-Tubes-Dual-Top-D-Getters-Tested-/371357014576?pt=LH_DefaultDomain_0&hash=item56769a5a30
  
 With all the examples above, please research the sellers/listings and buy at your own risk, although eBay has the best prices, it can sometimes be a miss.  Vendors may have similar types in stock, but I've found that with NOS, sometimes it isn't worth the extra price of their service, plus many times I can't actually see them until they arrive.  Most eBay sellers at least offer refunds if they are damaged in transit or if they do not work the first time you turn them on, but other than that though, you are stuck with them and would have to resell them if necessary.  If they sell a lot of tubes and have great feedback than usually they are honest with their test results and will work with you if you have issues.  I did not do this research myself for any of the links above, just quickly found them as examples.
  
 A great resource for information on NOS tubes in general is Tube World; they have some really useful info and a ton of pictures to boot!
  
https://www.tubeworld.com
  
 Maybe even giving the Psvane a wee bit more time may prove beneficial, as the sound may loosen up after a few more hours of burn-in.  I am, of course, just assuming that Grant Fidelity only burnt them in for a day or two, so they can better match them before sale, and that they were completely unused prior to this.  I haven't purchased many new production, but even some of my NOS were a little tight sounding in the beginning.


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## lucidreamer

You guys are awesome, thanks so much for your suggestions and recommendations!!! It may actually take me some time to sift through the information to decide which NOS tubes would be a good choice. There are quite a few of them to figure out what may be the best bet, plus the lack of trying/testing them before buying makes is like gambling.
  
 Just found some good comparison between RCA and GE NOS 6L6, it seems to be in line with what Effusion mentioned as well and the GE is a winner here (GE is more tubey sounding compared to RCA):
  
*The GE 6L6GC Grey Plates are smoother and more laid back sounding, which I like a lot. Horns are tamed a little, with less brashness & edge compared to the RCAs. The GEs are not quite as transparent as the RCAs, but still by any measure they are nicely transparent, with superb imaging & soundstaging, but perhaps not quite as an obvious sense of layering back into the depths of the soundstage as the RCAs possess. The GEs don’t have quite the same prowess as the RCAs when it comes to tempo, melody lines, and rhythm, but do best the RCAs in terms of timbre and tone color.*

*The verdict: I like the GE 6L6GC Grey Plates the best in my MC30s. They have a smoothness and richness that makes them easy on the ears, and as a side benefit they’re almost half the price of the RCA 6L6GC Black Plates. You might come to the opposite conclusion, and favor the RCAs for their superior low frequency performance, and snappy renditions of tempo, melody, and rhythm. All I can say is I’m glad I’ve got a set of both.*

*http://jeffsplace.me/wordpress/?p=5569*


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## lucidreamer

This listing says only a few hours were put on the EL34, but the seller does not really post any test data/results, pretty risky.... Maybe someone already bought from that seller and has good experience.
  
 http://www.ebay.com/itm/281726799211?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
  
  
 Is this listing basically for the same exact tube as =C= EL34 just branded as Marshall?
  
 http://www.ebay.com/itm/SVETLANA-WINGED-C-EL34-DUET-MARSHALL-/201369627557


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## JK-47

Thanks for the article 
	

	
	
		
		

		
		
	


	



  
 There are also different GE 6L6GC's depending on the year of manufacture.... Similar to the RCA's in the article, the height of the bottle changed somewhere in the mid to late 1960's. Square or circle getters, and round or oval spacers. Making for an interesting mix within the same GE family of 6L6GC's... I tend to prefer the earlier short bottle GE's myself, but I'm sure everyone will have their own preference. I almost forgot to mention that GE's 7581A is also a dead ringer for a late production (1970's-1980's) tall bottle 6L6GC (I'm sure they are one and the same). And to make matters worse GE made RCA'a 7581A's.... I have or have had examples of all the above mentioned tubes. They all sound very similar, with subtle nuances differentiating them.


----------



## lucidreamer

I just placed an order for a pair of new EL34 Winged =C= totalling $110 w/free shipping, the price is the same as everywhere (incl. eBay) give or take a few bucks. 
  
 https://www.tubesandmore.com/products/T-EL34-WC
  
 The eBay auction for used ones is already over $70. By the time it ends soon the price difference will not be that huge anyways.
  
 Seems that EL34 =C= is a great Russian tube with lots of raving reviews, some say it is better than JJ EL34 which sounds a bit veiled. Not sure if it will give me adequate bass in Triode mode(my favorite) or I should switch to Ultra-Linear for more power and bass, will see.... I will post my findings and impressions once it arrives, may need to give it some burn-in time. It is on the borderline between new production and NOS since =C= are no longer made and will be harder and harder to get.


----------



## lucidreamer

It's all your fault guys, I hate y'all!! 
	

	
	
		
		

		
			





 *YOU* just hooked me up on this never-ending, money-sucking, new-tubes-can-never-sound-too-perfect, your-only-remedy-is-NOS!!! tube-rolling journey.
	

	
	
		
		

		
		
	


	







!!!!
  
 Just made the 3d tube pair purchase in the last couple of days already and I should better stop NOW before my wife kicks me out of the house. I found a nice deal on eBay lately for a pair of *Vintage Mullard EL34 2X Halo Getter (with those double getter rings)**. *It seems to be not a true NOS/NIB, but it has great test readings and for $179 seems to be a smoking deal, they usually retail for $199 each from tube stores, like this one: https://www.tubedepot.com/products/el34-mullard-double-o-getter-welded-plates
  
 I also emailed the seller prior to purchasing them whether those were genuine Mullard tubes from the Blackburn facility and he confirmed that. The codes are "xf2 B5A1" "xf2 B5A2" which matched the "Bxxx" for Blackburn factory. Here is the listing: http://www.ebay.com/itm/181778264354. The pictures did not show the etched letters, therefore, I thought it was worth checking with the seller first.
  
 Did anyone have a chance to compare the Winged C/SED EL34 with vintage Mullard EL34 tubes? Do they really sound different or Mullard has an overall better tone, dynamics, etc.? I am kind of confused whether I should cancel/return the =C= now and keep the Mullards, but =C= that I bought earlier will be hard to get in the future for sure, maybe I should keep them both.


----------



## JK-47

Now you will need a tube tester...


----------



## lucidreamer

jk-47 said:


> Now you will need a tube tester...


 
 Yes, that may definitely be a good idea to get one in the long run. Thanks JK-47!
  
 Any possible thoughts/concerns about my recent eBay purchase of Mullard Vintage EL34s? How does the silver flasher look like? I really do not notice any visible issues with them, no brown/rainbow coloring, etc. but I could be wrong.
  
 http://www.ebay.com/itm/181778264354?rmvSB=true
  
 They seem to be a good deal and I hope they will be a decent match for Elekit TU8200DX. These readings seem to be pretty decent too, but I am not 100% familiar with that stuff yet:
  
 Results = 
 9900 µmhos  ~   59 mA
 9800 µmhos  ~   62 mA
  
 One thing for sure - no burn-in will be needed for them!


----------



## JK-47

From the ebay pics, they look fairly good, I can see the Blackburn "X" factory code in one of the pics, and the key way has the little pinhole on the bottom. Both signs of genuine Vintage Mullard tubes. Here is an excellent site for the different Philips/Mullard/Amperex tube models with their pictures and description.
  
 http://www.tube-classics.de/TC/Tubes/Valvo%20EL34/EL34.htm
  
 Tube testers can be a subjective issue... not everyone uses the same type of tester, or a calibrated tester for that matter. Tube testers can take up several pages of discussion all on their own, but I will say in the past several months my testers have saved me more than the cost of the testers... I have returned tubes that have not tested up to the sellers claim, and have had no problem returning them once I provide the seller with the results. I can also search out single tubes and match them with other singles (usually cheaper to find a single tube than a matched set).
  
 Enjoy your tubes


----------



## Greg70

lucidreamer said:


> Yes, that may definitely be a good idea to get one in the long run. Thanks JK-47!
> 
> Any possible thoughts/concerns about my recent eBay purchase of Mullard Vintage EL34s? How does the silver flasher look like? I really do not notice any visible issues with them, no brown/rainbow coloring, etc. but I could be wrong.
> 
> ...


 

 The flashing is definitely getting thin on those lucidreamer. Once you can see through it at the top of the tube they're near the end of their life from my experience.
 Compare it to the pictures on this page: http://www.tubeworld.com/el34mullard.htm
 You can see that when new the flashing extends well down from the top of the tube and you can't see through it.
 The Blackburn XF2 is a great tube though.
  
 You're right that the genuine winged C tubes are getting hard to get.
  
 The mode you like might depend on the tube you have in at the time. I used Triode with the KT-88s and U/L with EL34s.


----------



## lucidreamer

greg70 said:


> The flashing is definitely getting thin on those lucidreamer. Once you can see through it at the top of the tube they're near the end of their life from my experience.
> Compare it to the pictures on this page: http://www.tubeworld.com/el34mullard.htm
> You can see that when new the flashing extends well down from the top of the tube and you can't see through it.
> The Blackburn XF2 is a great tube though.
> ...


 
 Hi Greg,
  
 Thanks for your info and the links, appreciate it! Yes, I am totally with you on that one and also had some concerns regarding the fairly thin getter flashing on those tubes that I bought. For $180 no-one would be happy to buy a pair of duds for sure. The seller has 5k+ items on sale and I emailed her regarding the return policy, there should be no problem (minus shipping on me). I will see how they sound and will go from there. Maybe I am wrong, but the getter rings look like new and have no milky white residue on them, I think heavily used tubes should have getters discolored because of the heat and all that. 
  
 All in all they just cost half or third the price of true NOS double-ring Mullards from Blackburn which are pretty rare. If they last me a couple or more years with great sound, and I am sure they should do that, I will be happy and maybe later buy another pair. They do test pretty good though, not like new but still good, if the seller is honest with testing, of course 
	

	
	
		
		

		
		
	


	




. I mostly listen to the headphones on moderate levels, that may extend the life of tubes too maybe.
  
 I came across some article regarding EL34 from Mullard and their condition, pretty interesting (http://www.audiotubes.com/el34.htm):
  
EL34 / 6CA7 Mullard: The early versions of this tube had a metal collar around the base, and a mica spacer below the getter. These tubes are RARE and command high prices. Later versions had a brown micanol base, and a production series indicated by "XF" codes which are printed in black ink near the bottom of the glass. All of the Mullard tubes I have seen have a small hole in the very bottom of the octal centering pin. All genuine Mullard UK made tubes, beginning with the XF1 series, will have the Blackburn, England factory code on the glass. This will be down low on the side, on the second line of code below the XF type designation, beginning with a capital letter "B". Another trait is the often very dark top getter flashing, sometimes with a rainbow-hued "oil slick" appearance. This is normal, as the gettering was done at high temperature at the factory. *Some use will sometimes make the getter thin, brown, or patchy. This is also nothing to be concerned about, as these tubes will usually still test very good with no gas, and operate normally for years with faded getter patches. *These are, overall, just awesome tubes.*"XF1"* tubes have a very dark brown, sometimes streaked with metallic gold (mica flakes) somewhat wider base, with two getter rings. These usually have the old "shield" logo, sometimes with the "BVA" in a circle below that. These are rare, and their scarcity has pushed up the price. They are worth seeking out!*"XF2"* tubes have a slimmer base, may not be as dark brown, with two smaller getter rings, but I have seen some with a single getter ring. Again, these may be the "shield" logo, with or without the "BVA" logo. RCA, GE, Sylvania, and other USA brands of EL34 from the early to mid 1960s were usually Mullard made XF2 type.*"XF3 and XF4"* tubes have a single center getter ring (some XF4 tubes have two "D" shaped getters), and the plates are stamped together and not welded. These tubes are more often found with other brands on the label (Amperex, RCA, GE, etc.) and sometimes have black bases. Later Mullard tubes may be "IEC Mullard". These are still great tubes. BEWARE: late 1970s production Mullard and RCA (labeled Great Britain) that have crossed seams in the top glass were made in Japan! These are not Mullard UK made tubes, although they were made in a Japanese factory that Mullard helped set up and are decent tubes. To date, the only current-production tube that comes close to the legendary Mullard quality and sound is the new Groove Tubes Mullard XF2 reissue, the EL34M. They are at an attractive price, and you may wish to try these fine tubes as a very cost effective way to get the Mullard sound without having to worry about finding pairs of vintage Mullard tubes that match, and being able to find spare tubes.


----------



## lucidreamer

Just arrived a pair of new TAD 6L6GC-STR tubes from Amazon that I purchased a few days ago. I put them in and they sound pretty good for their price ($25 each) right out the box. The bass is tight and the top end sounds pretty airy and transparent. Compared to the stock 6L6EH which I already burned in for a few dozen hours the TAD tubes sound smoother, less grainy and more lively I think. Perhaps after they burn in a little more, I will swap them for EH again to check for better differences. Overall, very very good impressions with those, nice clean sound and non-fatiguing farily musical touch. I am still new to tubes, so please take my thoughts with a grain of salt, they are just impressions rather than the true characteristics of the sound.
  
 Since my used Mullard EL34 tubes did not arrive yet, I can hardly say how well these compare to vintage tubes, hopefully after the EL34 arrive they will make me feel sorry for any other new production tube purchases I have made so far. Not sure whether I did the right thing by buying those used ones yesterday with thin flashing on the tubes, there are still NOS double getter EL34 XF2 available which cost double the price but may be better and safer investment. I am contemplating getting NOS and return those used ones.


----------



## JK-47

lucidreamer said:


> Just arrived a pair of new TAD 6L6GC-STR tubes from Amazon that I purchased a few days ago. I put them in and they sound pretty good for their price ($25 each) right out the box. The bass is tight and the top end sounds pretty airy and transparent. Compared to the stock 6L6EH which I already burned in for a few dozen hours the TAD tubes sound smoother, less grainy and more lively I think. Perhaps after they burn in a little more, I will swap them for EH again to check for better differences. Overall, very very good impressions with those, nice clean sound and non-fatiguing farily musical touch. I am still new to tubes, so please take my thoughts with a grain of salt, they are just impressions rather than the true characteristics of the sound.
> 
> Since my used Mullard EL34 tubes did not arrive yet, I can hardly say how well these compare to vintage tubes, hopefully after the EL34 arrive they will make me feel sorry for any other new production tube purchases I have made so far. Not sure whether I did the right thing by buying those used ones yesterday with thin flashing on the tubes, there are still NOS double getter EL34 XF2 available which cost double the price but may be better and safer investment. I am contemplating getting NOS and return those used ones.


 
  Don't worry about being new to tubes, everyones impression's are welcomed. I haven't heard any reports on the TAD's, so I'm sure everyone appreciates your input.
  
 I have vintage Mullard "XF2" tubes and find they sound very different than anything in the 6L6GC family that I have.
  
 Welcome to the fun (insanity) of tube rolling....


----------



## lucidreamer

> I have vintage Mullard "XF2" tubes and find they sound very different than anything in the 6L6GC family that I have.


 
 Do they really live up to the hype and are worth the asking price of ~$400 for a pair of XF2 NOS because they are clearly superior in sound quality to other tubes or just different? Seems like many like them a lot while there are a few who say that EL34 do not have enough bass. The double halo getters ones seem to be more expensive and I found a place to get a pair of these for $379(NOS) while single getter ones could be found for less than $300. There should be no sound difference between those I think, double getters are just more sought after tubes and fall into a date range that is believed to be higher quality, therefore, the price is higher. There are also Westinghouse NOS XF2 on eBay now for $229 that are claimed to be made in Blackburn but they are likely made in Japan and should be still great vintage EL34s.


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## lucidreamer

Any possible thoughts/suggestions regarding getting those dual halo XF2 EL34? I think the flashing looks pretty good on those and they test 11,500 & 11,500 Gm on Hickok 539C (I wish I knew what that means





):


----------



## JK-47

Personally I prefer the 6L6GC/7581a family and KT66's, vintage models of course. But to each their own, and what they are willing to pay to obtain or hoard is different between people.

A few months ago I paid $110 for a pair of single getter el34 xf2's. They tested strong on my tester and we're closely matched. So deals are to be found if you're patient. 

Also, very few vintage tubes are truly "NOS".just because they are in a new box and the print on the tube is crisp and pristine. They can still test poorly...


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## Greg70

Here's my experience with used Mullard EL34s.. I bought a pair similar to the ones you have bought with little getter flashing on them.
 They sounded great, but the flashing got even thinner as I used them, and after maybe 20 hours one channel lost volume and I had to retire them. Keep in mind that these tubes are also not performing at their best as they approach the last few hours of life.
 I see a lot of tubes like this for sale, and I have come to the conclusion that there are people who use them up to this point and then sell them while they still show decent output on a tester, because they know when it's time to move them on.
  
 Do they live up to the hype ? Yes, they are the best of the best (in this family) as far as I'm concerned.. as long as the EL 34 is the tube for you. I think you need to confirm this first though.
 Try the ones you've bought, or buy (or borrow) a cheap pair of modern EL34s.. see if they're the right flavour for your taste and gear, and if so then IMO the NOS mullards are worth the investment. A good pair will last you many years.
 I agree with your assumption that the single halo is equivalent to the dual halo BTW. Anything different or rare always commands a higher price, but doesn't necessarily sound better.
  
 You can spend a fortune on tubes.. I hope this helps shorten the journey


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## Greg70

jk-47 said:


> Also, very few vintage rubes are truly "NOS".just because they are in a new box and the print on the tube is crisp and pristine. They can still test poorly...


 
 Very true JK-47.. buying NOS is a crap shoot.
 It can be so satisfying when you get a good deal and the tubes are good, but there are lots of people out there selling rubbish at inflated prices.


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## JK-47

greg70 said:


> Very true JK-47.. buying NOS is a crap shoot.
> It can be so satisfying when you get a good deal and the tubes are good, but there are lots of people out there selling rubbish at inflated prices.


 
 lucidreamer

 I can't remember who.... but someone earlier in this thread highly recommended investing in a tube tester. It has helped me tremendously dealing with used/vintage/NOS tubes, and have already paid for themselves... A strong investment if you plan on rolling/trading/selling tubes.


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## JK-47

lucidreamer said:


> Any possible thoughts/suggestions regarding getting those dual halo XF2 EL34? I think the flashing looks pretty good on those and they test 11,500 & 11,500 Gm on Hickok 539C (I wish I knew what that means
> 
> 
> 
> ...


 
 The 11,500 Gm on a Hickok 539C is the transconductance measurement. It is roughly an estimate of the tubes remaining life. On the actual Hickok tester there is a roll chart that tells you what position each knob has to be in for a particular tube before you press the "test" button, as well as the lowest acceptable Gm reading (I believe to fail Gm is 65% of what is considered new). Testing tubes is not an exact science and is open to argument and speculation. My model tube tester vs your model tube tester, did you measure the voltage of the wall socket the tube tester was plugged into, I use a Variac do you? was the dish washer or washing machine/dryer running, did you clean the pins of the tubes, are your tube testers sockets clean, was it raining, when and by who was your tester calibrated, what time of day were the tests taken... These are all questions I have run into when returning tubes...I kid you not. The funny thing is, all of them except maybe the rain can affect the test results.


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## lucidreamer

My first purchase of Mullard EL34 XF2 tubes arrived this morning. I put them into my amp and waited for 5 minutes to allow them warm up to test using some uncompressed tracks that I am very familiar with. Overall they do not sound bad and have some of that laid-back tubey syrupy sound that everyone was talking about. But I think for me and my planar HE-560 headphones they may not be the best match  Too much boost in the mids, when the strings are playing, I almost had to turn down the volume a little bit, it was unpleasant for ears indeed. The bass is not that bad but the highs are rolled off quite a bit. If someone uses headphones with pronounced treble region - those tubes may be great, but for HE-560 not so. That being said - not quite impressed with XF2, maybe these are lemons.
  
 I also hoped to get some richer harmonics from these tubes but I could not hear them. Maybe these tubes are too old and lost their 'mojo' over time. I should get another pair of EL34 on Monday and hopefully they will sound better because of the test readings and overall newer condition, good getter flashing, etc.. But those ones that I got today will be on their way back to seller (unfortunately). I guess the shipping charge is on me, oh well 
  
 So far - my favorite choice for power tubes so far is still "TAD 6L6GC". I really dig the sound of these new tubes. Just put my stock 6L6EH back for a change and TAD 6L6GC really ate them for breakfast! They both sound somewhat similar in tone and frequency range and are on the warmer side, but the TAD tubes have more details, less harshness, less veil, they sound more natural and also have some interesting tickle-visceral bassy touch during listening to some songs, that is really cool, I can tell each bass note distinctly. And they have some pleasant harmonic texture in the whole range which is very balanced too. Other tubes I tried did not have that, however, I only tested a few at that point and would like to try some NOS 6L6GC too.
  
 I would highly recommend those TAD tubes to anyone just to try and see what you guys think, I am sure that I would not be the only one who liked them. And they are only $50 for a pair NEW on Amazon! Not sure whether they are Russian or Chinese-made, it says "Designed and Handcrafted in Germany" on the box.


----------



## lucidreamer

Just noticed that using socket savers for tubes(especially for power ones) really helps to reduce the amount of heat imposed on the amplifier chassis and the tubes stay cooler too! Not sure why but earlier I could not even touch the base on TAD 6L6 when they are running, they felt pretty hot when touching with a finger even for half-a-second. After installing the socket savers that I got today from eBay, I can keep the finger on the bases for a couple of seconds just fine, probably no more than that. Plus the top metal plate and the sides of the amplifier feel less warm too. Not a huge difference but still better than before, I think it is still worth sharing this trick with everyone.
  
 I know that using socket savers to protect sockets on amplifiers is an overkill, they are meant for tube testers to protect the sockets from thousands of tube changes, but for $20 bucks it is still a good 'cooling technique' in my mind, the sound does not get affected at all.
  

  
 Another thing I learned with this amp.... The red plastic jumper wire is pretty thin, brittle and breaks easily (do not ask me how I know). Looks like it is made from some brass alloy. I tested tubes with changing the mode from triode to UL the other night and used a set of needle pliers to help install the jumper. Maybe I pushed it down too hard but the jumper wire bent to the side, I tried to straighten it up and it just broke on the end where it is shaped as "V". I replaced it with the same jumper taken from the LED and then fixed the it using the wire from some steel spring. I guess the LED wire resistance (brass vs steel) is not important as long as both mode jumpers are the same. Works great. Ideally if the mode setting is not used - I would prefer soldering the mode jumper connection for better conductivity, those jumpers seem to be a weak link in the chain, very thin wire is used, but maybe the voltage is small anyways.


----------



## lucidreamer

I guess I was wrong about the EL34 XF2 tubes because the first one that I bought on eBay turned out to be lemons
	

	
	
		
		

		
		
	


	




 They were likely driven too hard before (maybe used in a guitar amp by some crazy rockstar 
	

	
	
		
		

		
		
	


	




) or something like that. Definitely missed some clarity and sounded veiled and dull overall. The flasher on them was pretty thin and receded too, I should have checked the pictures better and stayed away from them in the first place. All in all, the seller has a return policy and I shipped them back already.
  
 I just got another pair of XF2 yesterday (the ones on the picture with the seashell that I posted before). They are in much much better condition at a great price and the flasher looks more solid and dark. I plugged them in and what a surprise.... The sound is clean and very pleasant with silky smooth highs and deep bass, some would call the sound signature of these tubes a little roaring and barking (in a good sense), but I really dig that sound, that is something I was actually looking for!!! It is amazing how detailed the sound is without being any fatiguing and harsh. Very liquid mids and bell-like highs, a really tubey sound at last. I am pretty happy with the purchase so far and may think of investing into a pair of real NOS XF2 or XF1 in the future. Not sure how long these used XF2 will last me without the sound going south, hopefully a few years out of them would justify the price paid. 
  

  

  
  
 Anyone had an opportunity to compare XF1 and XF2 by chance? There are some great deals found on eBay for real unused XF1 sometimes and XF1 is considered to be a more regarded tube with better headroom. Mullard XF1 are pretty costly but I saw some XF1 re-labelled as Dynaco or Heath for much less and they look authentic with XF1 and Bxxx codes etched with the small hole in the center pin. Are they truly legit Mullard XF1 tubes or something else maybe?
  
 Real NOS XF2 are more common and can still be found from reputable dealers for somewhere in the $350-400 range. I agree that without the tester it is pretty risky to pay that amount of money on eBay for a pair tubes, but from a reputable dealer with great ratings it makes me feel more secure. I do not think I will probably buy a tester anyway, since I prefer a EL34 NOS now and will be happy to get a NOS pair to live with for now, maybe later will consider another type.
  
 I put my Psvane KT88 MKII for sale today under Classified, they are like new with very few hours and are great production tubes. If someone is interested - send me a pm.


----------



## Effusion

Sorry to hear about the first pair... but I'm glad are able to return them.  I don't believe you can tell much when the input tubes start to go, but with the power tubes, they will tend to lose impact/gain once they're close.
  
 I'm glad to hear you're digging the second pair though and it sounds like you got a good deal.  For extending lifespan, just be extra careful when moving them around and try not to turn them on/off more frequently than necessary, within reason though.
  
 I find the EL34 to be a detailed, airy, tubey at times, and somewhat polite tube in general.  I think you may also really like the KT66s as well though.  I guess one could simplify their comparison saying that they are somewhere between the KT88 and the EL34, very nice all around!  I prefer the smoked-glass Genalex, but the GEC and Mullards are nice as well.  Many go up for sale, but they can go for a bit, also one must consider that many have to be shipped overseas; I've only had 2 problems before because of this though and was refunded both times.  There are a few new production KT66s, but not many and mostly for guitar amps, etc.
  
 In addition, even the 807s are nice, especially for the price.  You need adapters to use them though; make sure they have good contact points as I don't think you want them to come off if the shelve is bumped.  I've found that the European and some non-RCA variants' top pin tends to be a little smaller in diameter, so it's good to have sets of slightly different sized adapters if you want to try quite a few.  Unlike other variants, many can be had on the cheap, especially the US made RCAs.  The European variants can go for a bit more, but not too much in comparison.  There is also a militarized version, the 5933WA, which sounds good as well, but may be a little more clinical than you may prefer; the 807s tend to be a bit warmer and with more bloom.  However, they're not as open and airy as the EL34s or KT66s are, but they have a nice tone and usually sound great for the money.
  
 Have you been able to compare the Mullards to the TADs at all?
  
 Probably your best bet is to try a different type of 6L6GC, at least in the short run, as they tend to be a bit cheaper and sound really good for their price.  I believe you may enjoy many different types, but for the price usually the GEs are a safer bet.  The RCA Black Plates are nice as well, but tend to cost quite a bit more.  However I've found that the KT66s add just a bit more sweetness and body to the sound overall, maybe a little bit more tubey sounding, and often when it counts, but they go for more cash.  Ultimately it all depends on how much you like the EL34s and where you think you want to go though.


----------



## lucidreamer

Thanks for your suggestions and tube recommendations Effusion! Really lots of good info to help during the learning curve. I guess I am sticking with XF2 EL34 for now, really enjoy their mellow tubey non-fatiguing sound and am considering investing into a pair of true NOS XF2 for the future and stash them away somewhere until these used ones die. Who knows how long the NOS Mullards will be available for at that price, since prices are going up already as we speak. The cheapest new(guaranteed) XF2 I could find was at $345 from the non-eBay online seller. I am also waiting for a pair of XF1 (supposedly new) that I picked up on eBay last week for a great price and if they turn out to be a real deal, I may keep them as spares instead of XF1. On the pictures they look legit with internal structure 100% matching those reference photos of XF1 in stores. The label says "HEATH By Mullard" but it was common in those days as well as Dynaco or EICO, etc.
  
 Here are some pictures of those XF1 that I bought, any thoughts/ideas if that is a real NOS XF1 tube or possible fakes maybe? I am kind of nervous since the seller has no return policy but has over 500+ feedback with no negative ones which gives me some relief:
  
 The getter flashing seems solid and robust on these:

  
 On this photo below the central pin holes look slightly different with the one on the right slightly bigger or maybe it is just the picture angle:

  

  

  
  
 Hard to figure out the difference between those XF(#) versions, some people prefer XF1 and some like XF2 better, or even Dutch-made XF3/XF3 with double "D" getters. I asked my wife to listen to some music with those XF2 tubes and she said they did sound very pleasant, usually she does not hear big differences between my audio gear changes. When I played the "Blessed" song from Elton John's "Made In England" 1995 CD - she said it even gave her some chills 
	

	
	
		
		

		
		
	


	




. Really feels like swimming in the ocean of pure music with these NOS tubes!
  
 I just got two pairs of cheap pre-amp tubes from eBay today - both are almost new vintage Westinghouse 12AU7 but one is labelled CONN and cost less, they are the same internally which is a fool-proof indicator of the origin. They seem to be great-sounding input tubes indeed, I think they have bigger soundstage and deeper bass compared to Psvane 12AU7 MKII ones which are good too but sound less involving and open compared to these. They really make the music sing. Maybe Psvane needs more burn-in time or something.
  
 These Westinghouse 12AU7 sell for $185 in stores for a pair but you can easily find great deals on eBay where sell for $20-35 a pair!!!! Just need to make sure that these are real Westinghouse and not RCA which are close: Westinghouse have "D" getter with 2 adjacent crossbars, grey dots around the type name, 337 (if the silkscreen is good) and other marks. There are some great reviews about this tube, looks like it is a real "audiophile" secret gem not known to many. Also, on eBay I was about to buy a new pair of RCA black plate "DG" 6L6GC that was sold for $112 to the highest bidder! Since I already like EL34 I decided to pass on those but it was a good deal! Those tubes usually run for $300-350 in stores.


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## JK-47

Congrats on the new tubes lucidreamer !!!
  
 Enjoy the tubes and keep us posted on how things sound


----------



## lucidreamer

jk-47 said:


> Congrats on the new tubes lucidreamer !!!
> 
> Enjoy the tubes and keep us posted on how things sound


 
 Thanks JK-47! Will definitely keep everyone posted on the new tubes and how they sound. I really find this forum thread very helpful and already went through all the posts from the beginning a while ago. I guess it is in our everyone's best interest to share our findings, knowledge and experiences with different tubes, brands, sellers, etc... just to help each become more proficient with tubes and avoid any headaches or bad surprises. Just came across some good guide that includes the section on NOS auction site purchases: http://www.greenbulletmics.com/VACUUM_TUBES.html


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## lucidreamer

Still waiting for my EL34 XF1 tubes to arrive, should be here today as expected but are delayed by USPS and did not arrive to Florida yet as of now.
  
 I checked with someone online regarding whether these are truly NOS tubes and based on his tube experience they are used ones but should still be ok as long as they test good. Unfortunately I do not have a tester(yet). The flashing is definitely smaller and there are some darker soot marks on the inner glass next to the rectangular exhaust vent holes caused by hot gases which indicates solid usage(see highlighted picture). Pretty hard to notice unless you really know what to look for! I am not pretty happy about it because the seller explicitly stated in the email that those tubes were NOS/NIB and were never put in the amplifier only in the tester. Looks like eBay is a huge tube rip-off scam zone, you would really need to know a lot about tubes to tell those tiny things.


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## lucidreamer

Now I start worrying that my new tubes may be lost in transit or something. They were supposed to arrive yesterday but the USPS tracking page did not change for the last 3 days, strange 
	

	
	
		
		

		
		
	


	




 I called USPS to find out what is going on but their customer support really sucks 
	

	
	
		
		

		
		
	


	



  
 Anyone experienced the same issue with USPS? It is a long way from OR to FL but I think Priority Mail 2-Day should be by air and not ground. I guess I am just becoming paranoid.


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## lucidreamer

Finally got the XF1 today. After I put them into my Elekit, they sounded pretty good, but after about 2 minutes of so, the right channel went quiet and the power light turned pink. I quickly turned it off and waited a few minutes, then put my original XF2 tubes back in. Now I have a slight humming noise coming from the right channel even when the volume pot control is all the way down. I tried different tubes and still the same result. I took the amp apart (partially) and swapped the output transformer, but the noise is still there, so it looks like some part went bad, but the transformers are fine. I emailed Victor and he suggested checking the FETs, since bad tubes may damage FETs that are used to bias the tubes. I checked the resistance of all FETs and looks like Q4 (right channel) has different readings compared to Q3 which may be a sign of the burned FET. No smoke, no burned parts are seen. Pretty frustrated with this shopping experience, looks like the person who sold me those tubes is not a very honest seller and knew about the issue. Those tubes are not NOS or NIB for sure  I already filed the return with eBay to return the tubes.


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## lucidreamer

The seller emailed me back and refuses to refund the purchase saying that he did not provide any guarantee on vintage stuff, those "new" tubes that he sold me could fail at any time and blaming my amplifier on burning the tube because the bias was set wrong. Very, very dishonest seller and someone not to recommend buying from. I am taking this to eBay because I was scammed. He stated that the tubes were new and never used in his emails and item description but upon the close inspection there are heavy contact marks on the pins, burn marks against the rectangular exhaust vents and receded flashing. I had a thought that they were used but never thought that they were defective and now I am stuck with the broken amplifier. He took the flashing pictures at an angle, so the flashing length is not that clear. Almost all his listings say NOS/NIB and he gets great reviews, I do not understand how it is possible!!!!
  
 I guess I should still be eligible for the eBay buyer protection because the actual item condition was not matching the description. It says NIB/NOS in the description but the tubes are used (and defective). Any possible suggestions/recommendations how to get my money back. He mentioned 'no returns, no guarantee, etc.' in the description, but he should have said 'used' not NOS/NIB, right?
  
 If I am not lucky and this crooked eBay seller gets away, I will have to leave a negative feedback on his account and disclose his details, so that everyone gets educated and never deals with this person.


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## JK-47

lucidreamer said:


> The seller emailed me back and refuses to refund the purchase saying that he did not provide any guarantee on vintage stuff, those "new" tubes that he sold me could fail at any time and blaming my amplifier on burning the tube because the bias was set wrong. Very, very dishonest seller and someone not to recommend buying from. I am taking this to eBay because I was scammed. He stated that the tubes were new and never used in his emails and item description but upon the close inspection there are heavy contact marks on the pins, burn marks against the rectangular exhaust vents and receded flashing. I had a thought that they were used but never thought that they were defective and now I am stuck with the broken amplifier. He took the flashing pictures at an angle, so the flashing length is not that clear. Almost all his listings say NOS/NIB and he gets great reviews, I do not understand how it is possible!!!!
> 
> I guess I should still be eligible for the eBay buyer protection because the actual item condition was not matching the description. It says NIB/NOS in the description but the tubes are used (and defective). Any possible suggestions/recommendations how to get my money back. He mentioned 'no returns, no guarantee, etc.' in the description, but he should have said 'used' not NOS/NIB, right?
> 
> If I am not lucky and this crooked eBay seller gets away, I will have to leave a negative feedback on his account and disclose his details, so that everyone gets educated and never deals with this person.


 

  Sorry to hear of the problems. Ebay is fairly good at getting your money back since the item was not as described.
  
 Also, not to mention our Elekit-TU8200's auto bias...


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## lucidreamer

Thanks JK-47. Hope so, but who knows what they decide. I am attaching pictures to my case with proof why these tubes are not new, hopefully they make sense to those who work for eBay.
  
 About the possible FET damage - does anybody have similar experiences by chance? Is that possible that something else could have been burned by the bad tube maybe?
  
 I checked the UNIT-1 board and cannot see anything unusual.


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## Effusion

I'm sorry to hear about that, not cool at all.
  
 I also blew my Q3 FET, using a QV05-25 tube though, and I'm very curious to find out what might have happened to the FET in your unit as well.  Now the QV05-25, which is a European 807 variant, is not rated for this amplifier and was out of spec; I shouldn't have even used it, but at the time it was listed on the radio tube museum site as a direct replacement, so I trusted it.  Like you my channel went dead (left one) and then the LED turned in color.  There was also a pretty loud hum in the channel that blew with other "working" tubes and even with no sound, just as you describe.
  
 However, I did get the QV05-25 Mullards that blew the channel professionally tested locally and they were well above NOS levels, plus they look immaculate and unused.  At one time I thought it was just a bad tube, until I had them double tested and verified, than I realized through a little digging around that the voltages were too high.  Was a really big shame as I couldn't return them, since they tested and looked perfect, and so my amp was out of service for short while.  I totally understand your frustration!
  
 Do you happen to have a way to get the EL34s tested locally?  I also wonder if they could have been damaged in shipping... were they packed pretty well in the box on delivery?
  
 The only time I've blown anything in any of my tube amplifiers was the FET on this Elekit, which I was convinced, until your post, that it was because of the type of tube I tried.  However, I've yet to have a tube fail while actually using this amplifier.  I have had several tubes fail in my other two amplifiers and nothing was ever affected besides just the tube; one tube even popped extremely loud and lit up with bright blue light, before the structure tipped over inside and the tube went completely out; it was quite the sight!  Still though, nothing was wrong with the Darkvoice 366SE and I've used it for years since.  There are also a ton of users out there who have had some of the cheaper Chinese tubes go out on them quite regularly, but never with issue to their amp, mostly guitar amplifiers though.  I've always understood that generally tube amps have safe guards built in so that a failing tube doesn't damage the amp, or at least they will minimize it and especially if it just runs down.
  
 I don't believe I've ever had a tube that had a short though, or possibly developed one during shipping, and I definitely could see this causing an issue; however, it is strange that it happened a few minutes after you turned them on and not right away, if it was a short.  Any chance you heard them before it happened?  The QV05-25 sounded really good BTW; that is for about 5 minutes until it happened.  Almost all, but the really cheap/tiny testers, include simple tests for shorts and leakage, etc. and is generally the first thing you have to test for when using most testers as some shorts can even damage the testers.  My understanding was that besides installing the tube in the wrong alignment (as with one without a guide pin), the next worst thing to do is to use a tube with a bad short.
  
 Really sorry to hear about how the seller is acting... I've been lucky and haven't had to return many, but at least the ones that were damaged in shipping were refunded and I've never had to pursue.  Did he test the tubes and/or provide test results?  If he can't provide proof that the tubes are in-fact NOS (very unlikely) nor that there is no way they were damaged in shipping (insurance?), than I say you have a case.  The hypothetical crap from sellers is mostly a thing from the past, as eBay is now tougher on them.  If you sell something for somebody to use, than it better not fail in the first 10 minutes of use, unless that is to be expected... just crazy.


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## lucidreamer

effusion said:


> I'm sorry to hear about that, not cool at all.
> 
> I also blew my Q3 FET, using a QV05-25 tube though, and I'm very curious to find out what might have happened to the FET in your unit as well.  Now the QV05-25, which is a European 807 variant, is not rated for this amplifier and was out of spec; I shouldn't have even used it, but at the time it was listed on the radio tube museum site as a direct replacement, so I trusted it.  Like you my channel went dead (left one) and then the LED turned in color.  There was also a pretty loud hum in the channel that blew with other "working" tubes and even with no sound, just as you describe.
> 
> ...


 
  
 Thanks a lot Effusion for sharing your experiences. Looks like after your Q3 went bad too which resulted in some humming noise in the left channel with the volume down? Q4 is the same FET only for the right channel. The humming is not very loud though and I cannot really hear it when the music is playing but it gets pretty obvious between the songs and no source connected. 
  
 Just curious.... how did you figure out it was the Q3 FET that went bad. Did you also test it with the meter and it showed different resistance? 
  
 My concern is that there may be more than just FET that blew in the amp but Victor told me over the phone that it was the one and he seems to know the stuff. He mentioned that many people buy used bad tubes on eBay (like me) and it sends too much current that burns the FET. Is that possible that other parts could be damaged but it still sounds as before but it will eventually kill my other tubes? I would probably test the voltage points that are indicated on the electronic schematic to see if they match.
  
 I am not that knowledgeable about tubes yet and probably cannot answer some of your questions... I will check with some of my local friends to see if someone has a tester to check those tubes.
 I do not believe that the tube was damaged during the shipping because it was packaged pretty well and the box did not show any sign of damage. There are no loose parts inside the tubes or badly burned electrodes. However, it is possible that it could be shorting after getting hot, since it happened right after a minute or two after I put it in the amplifier. I think the seller knew about the bad tube or did not test it long enough using the tester. It would have shown the issue on the tester if he really did test them. I believe that he did not even test all of his tubes because there was no picture on the listing showing the tester with the results, therefore, I should probably use is as my argument with escalating the case. All in all - no-one should be selling junk tubes as NIB/NOS, right?
  
 There was really no way I would be able to install it with the wrong alignment, because the pin was not repaired or missing and I am pretty anal about that too.
  
 Thanks again guys!


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## Effusion

You're very welcome and I hope it helps.  I was just about to finish this review when it happened to me, so I also know how frustrating it can be.
  
 You're right, you probably have a good claim with just the pictures alone, regardless that it malfunctioned, as sad as that is.  If he was listing them as NOS/NIB, than that's what they need to be... just too bad they had to also be defective/blown.
  
 I actually contacted Victor right after my FET blew and after talking with Mr. Fujita that night, he was convinced it was the Q3 FET, which it was, and only that.  Victor also told me it was because of a bad tube and I now have a few backups.  I had just never had an issue with my other amps and I was going to try to return them, so I brought them in to be tested on a heavily used top of the line Hickok machine and they were strong with plenty of life, passing all tests as good as they can.  They also looked perfect and completely unused (many times you can tell the easiest from the pins, besides excessive scraping, they will darken over time of use as well).  I then found out that they shouldn't even be used in an 807 circuits as their specs are outside the range normally designed for... so, I've been thinking that it was because of this out of specification of that particular tube, my FET blew, but now, after your issue with a fully-in spec variant, I'm wondering if it can blow in many different circumstances.
  
 It would be interesting to find out more though...


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## lucidreamer

effusion said:


> You're very welcome and I hope it helps.  I was just about to finish this review when it happened to me, so I also know how frustrating it can be.
> 
> You're right, you probably have a good claim with just the pictures alone, regardless that it malfunctioned, as sad as that is.  If he was listing them as NOS/NIB, than that's what they need to be... just too bad they had to also be defective/blown.
> 
> ...


 
  
 Yeah, I have really no clue why would it blow the FET in my amp or maybe something else too because XF1 EL34 is a perfect tube for this amplifier. Likely the tube was bad due to age or shorted when getting hot.
  
 The good news is that the seller finally agreed to refund me and I am shipping the tubes back to him tomorrow. I believe one of the tubes was bad before already. But he either used some old tester (as seen from other listings) and those testers only put somewhere 100v to the tube plates which make them useless for power tubes that can run at 250-500v or more. I just suggested that he did test them for more than a minute or two, since that was the case here. He even called me a crook and said it was my Chinese POS amplifier that burned his perfect tube, etc. I just know that it was not true, they did not look NOS. I had a feeling that these were not real NOS before getting them but i was ok to live with that as long as those tubes worked ok.
  
 Anyhow - I fully agree, they should never sell old used tubes on eBay as NOS/NIB even if tubes are still reading great on the tester. The word "NOS" does not apply here because NOS means that the tube never ever been used in an amplifier - period. If the seller does not have any negative feedback - that is actually someone like me are not leaving them because the case is settled. So it is really a risky shopping experience and needs some good tube knowledge to tell the good stuff from junk.
  
 I actually read about new production tubes too from Russia and China blowing amps which is kind of scary. If NOS and new tubes can do that - what are we left with?
	

	
	
		
		

		
			





 Or we should be putting new FETs into amps like fuses every day?


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## lucidreamer

I wonder if someone in the US has a spare NDF02N60ZH FET that they could sell to me, I would be happy to get one quickly to fix my amp. Please let me know.
  
 I already placed an order with Victor for them but it can take a week or so to get it from Canada to me in Florida.
  
 These parts can be ordered from Asia online through US dealers but the leadtime is a few weeks, I could not find any in stock here in the US to get them faster.
  
 http://www.mouser.com/ProductDetail/ON-Semiconductor/NDF02N60ZH/?qs=3PKVEWFFm29mKP%252bYzgkGqQ%3D%3D
 http://www.onsemi.com/PowerSolutions/availability.do?part=NDF02N60ZH
  
  
 Thank you!


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## lucidreamer

I took the Q4 FET out of the board and checked the source and ground resistance with the meter. It reads almost no resistance for Q4 where other FETs have resistance in mega Ohm range without the load. Definitely something bad with Q4.
  
 I think the heat sink would be a good idea to install on all four of them.


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## lucidreamer

Besides Victor being so great and providing us with replacement parts for TU8200DX, I believe equivalent FETs can also be ordered faster within the US too:
  
 http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=NDF02N60ZG
  
 Based on the specs/datasheet data both NDF02N60ZH and NDF02N60ZG is the same exact FET with slightly different case/pin length:
  
 http://www.mouser.com/ds/2/308/NDF02N60Z-D-252901.pdf
  
 Thoughts?


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## Greg70

Sorry to hear about your problems lucidreamer.
 You can get the FETs from Mouser: http://www.mouser.com/Search/Refine.aspx?Keyword=NDF02N60ZH


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## lucidreamer

greg70 said:


> Sorry to hear about your problems lucidreamer.
> You can get the FETs from Mouser: http://www.mouser.com/Search/Refine.aspx?Keyword=NDF02N60ZH


 
 Thanks Greg. I see that you also went through the same issue with a bad vintage tube that had a pin repaired wrong?
  
 I just have 10 NDF02N60ZG FETs from Amazon.com on the way already, paid only $16 for 10 of them with shipping which was a good deal. NDF02N60ZG is the same as NDF02N60ZH which is impossible to order from the US and it takes 6-8 weeks of leadtime from the manufacturer.  Victor also sent me four FETs from Canada too which should arrive next week or so. That will be plenty to have stock if those FETs fail again in the future. I actually read that good tubes may be getting bad because of age which can damage resistors or FETs. One cool trick I read somewhere was to avoid moving the amplifier when the tubes are still which can reduce the tube's lifetime and cause lead shorting each other in the long run. I have my amp on a A/V cart with caster wheels to move it around different rooms in the house, so I will now try to wait and let the tubes cool down before moving the cart.
  
 I am pretty sure that these are the same exact transistors based on the datasheet (both H and G versions), only tiny case differences. Looks like Mouse has an error posting some numbers on the page that you linked, those numbers belong to NDF and NDD variations.
  
 Just curious if someone replaced the stock NDF02N60ZH with NDF02N60ZG or I will be the first one?


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## vkung

lucidreamer said:


> Just curious if someone replaced the stock NDF02N60ZH with NDF02N60ZG or I will be the first one?


 
They  are basically the same chip, but  the “package” is different.
NDF02N60ZH has a shorter pin lead than NDF02N60ZG.  You can use ZG to replace ZG.  I  must order this part from Japan. 
.


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## lucidreamer

Life is good again
	

	
	
		
		

		
		
	


	




!!!
  
 I fixed my Elekit today by replacing Q3 and Q4 with new FETs from Amazon. I decided to replace both with the same part # and also because I put the bad tube into the left and the right channels. The noise was only coming from the right channel (bad Q4) but who knows if Q3 was also affected by the bad tube.
  
 Also, I found a couple of heatsinks laying around from previous projects that perfectly matched the FETs and soldered them vertically with the heatsinks attached with the screw and the nut. There seems to be lots of space under the board to fit them in vertical position.
  
 There should be no reason to use the heatsinks on Q2 and Q5 that supply the voltage to the input tubes, since the voltage is much lower and these FETs should stay cooler aanyway.


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## vkung

you don't heat sink for the FET.


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## lucidreamer

vkung said:


> you don't heat sink for the FET.


 
  
 Thanks Victor, I know using the heatsinks for those FETs would probably be an overkill since they are rated for 600V and Elekit only uses less than 300V and never produce excessive heat to dissipate. I just saw the heatsinks mentioned in the FET datasheet and decided to put them on.


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## vkung

you don't need heat sink
the problem is the bad tube


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## lucidreamer

Right, definitely a bad tube, they are on their way to the seller already. The seller insisted that he did test them for 5 minutes and they were reading ok on his tester. Not sure if his TV-7 A/U tester that was made in the 50's actually produces accurate results on power tubes that should really be tested at 400-500V on the plates. Just selling used tubes as NOS/NIB ones should already be a red flag for buyers.


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## Effusion

Glad to hear that the seller is allowing the return and making things right.  If the test ratings for the set were just "okay" on his tester, he should have never labeled the listing as NIB... crazy.
  
 As far as the readings on his tester for power tubes, almost all of the vintage testers have issues with weak transformers and thus, may read certain power tubes with more inaccuracy than others.  Over time, not only use, but even by just sitting on a shelf, the transformers will eventually start to weaken.  Unfortunately there are very few, if really any, options for new transformers, since they are unique to these testers and have to be hand-wound, etc.  In general, vintage testers with weak transformers will have issues with the higher output power tubes, such as KT88s and 6550s; EL34s are generally less taxing on the transformer and thus will often provide more accurate results though.  A gas/leakage and short test shouldn't be affected by the power of the transformer though and the Hickok "Life" test can also indicate if a tube is near the end; I've had tubes with great emissions results, etc., but with an extremely poor life test, so it can be useful.
  
 Let us know how the repair goes and if you ever find out from the seller if one of the tubes now tests bad; it's also smart to have a few extra FETs, just in case this happens again.  It would be helpful if all of us were able to get a better idea of what will/can happen when a tube fails in the Elekit though, if this is what happened to cause the FET to blow.  Eventually, even with the newer production batches, and sometimes even more often with them than vintage, all tubes will fail, so it will happen at some point.  I find it interesting that unlike my other experiences with tube amplifiers, the Elekit seems to have issues with dying tubes, beyond just the tubes, however I'm still wondering what the ultimate verdict may be, as the structure did not collapse/spark when the LED turned and the sound cut out.  Thus, it would be interesting to find out if it was just something wrong with one of the tubes or that their life had finally been used up.
  
 I hope you're up and running again soon!


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## lucidreamer

effusion said:


> Glad to hear that the seller is allowing the return and making things right.  If the test ratings for the set were just "okay" on his tester, he should have never labeled the listing as NIB... crazy.
> 
> As far as the readings on his tester for power tubes, almost all of the vintage testers have issues with weak transformers and thus, may read certain power tubes with more inaccuracy than others.  Over time, not only use, but even by just sitting on a shelf, the transformers will eventually start to weaken.  Unfortunately there are very few, if really any, options for new transformers, since they are unique to these testers and have to be hand-wound, etc.  In general, vintage testers with weak transformers will have issues with the higher output power tubes, such as KT88s and 6550s; EL34s are generally less taxing on the transformer and thus will often provide more accurate results though.  A gas/leakage and short test shouldn't be affected by the power of the transformer though and the Hickok "Life" test can also indicate if a tube is near the end; I've had tubes with great emissions results, etc., but with an extremely poor life test, so it can be useful.
> 
> ...


 
  
 Thanks Effusion! I actually got the spare FETs from Amazon last Saturday and fixed my amp already by replacing both Q3 and Q4 with NDF02N60ZG FETs. It sounds the same as before (knock on wood) with my other NOS Westingate EL34 single getter tubes that I got from eBay. These are really new set of EL34 XF2 tubes that I bought for a fair price on eBay. I think from now on I will try to stay away from used tubes and sellers who have no return policy, just too much headache and risk to use your amplifier as a tube tester. I cannot hear any sound differences between EL34 double-getter and single-getter tubes, but the latter costs 1/3 less which are also easier to find NOS! I think it is a really a great deal as long as it lasts.
  
 It would be great to have some additional "bad tube" electronic protection implemented in the amplifier design to prevent blowing FETs and other parts, something like small replaceable fuses or cut-off relays, etc. I have no clue what could cause the XF1 tube go bad, as mentioned before, both tubes sounded just fine for about a minute or less, then one channel died quickly and I had a red light come up. Probably over the age, some pins or leads internally started shorting out as soon as the tube heated caused by tiny expansion in the metal structure due to heat. The tube was still glowing up normally as before, no pops or sparks were visible. Depending on what specific pin may be shorting I believe that this guy's tester may still be reading this tube as good, since the tube did not explode or died completely. That is why it is really wise for professional tube sellers to invest into really good modern tube testing equipment. Based on his irate responses, plain lies and contradictory arguments there will be no surprise to see these tubes popping up for sale again in the near future only making eBay an even worse place for audiophiles. Caveat Emptor!


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## JK-47

lucidreamer,
  
 Glad to hear everything is back to normal... or somewhat normal.
  
 The world of tubes can be slippery and frustrating at times, but the reward is oh so sweet


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## Effusion

Good point about what can happen when getting the voltages up to operating voltages on vintage tubes.  It is always a bad idea to start up a pair that are cold as well; a sudden change in temperature will often be enough to snap something, so try to make sure they are at room temperature prior to use.  If you have any that ship over the winter it is useful to let them sit out of the packaging for a few hours at least.
  
 A few modern testers will and do test at close to full power output, for which they claim gives a truer emissions test, I also agree that it would and does.  Unfortunately, most modern testers aren't as versatile as many vintage ones, often requiring multiple testers, and they're also not really any good cheaper options.  Many, if not most, tube resellers also still use all vintage equipment for their results, so trying to file claims if you are not satisfied with the results can be a little tougher sometimes.  It all makes me think why there isn't something to fill this demand niche, such as modern tester with better features (maybe even a "Hickok" measurement mode that's close), more versatility, and all at a reasonable price point... too much to ask I guess, but with the amount of tubes being tested and traded even on eBay, I think there may be a pretty good market out there for one.
  
 As far as eBay, it's usually cheaper and definitely more plentiful then other vendors, but most listed are used to just slightly used and very few are actually true NOS.  You can get lucky from time to time and the pictures are key, but there is more risk and headache if something goes awry than maybe at other places.  Generally for a price, going with a more established vendor can be the way to go to avoid dishonesty and unnecessary headaches, giving the assurance that it would be taken care of if needed.  This isn't always the case though, as even a few of them I wouldn't recommend due to pairs I paid too much for, thinking they would be different and that also showed signs of use/wear, plus very few have a return policy if you just don't like the sound, etc.
  
 Several of the folks here have experiences with a few testers as well as research/issues surrounding them, so make sure to let us know if you are ever interested.
  
 I find it quite interesting and actually a little funny about your take on the different versions of the Mullards; sometimes rarity plays a bigger factor than we realize and hype can often cloud judgment.  You may find that in general, many prefer the older and militarized versions often the best, where many claim that the sound is generally both cleaner and with better/enhanced characteristics.  This is obviously not always the case, so rarity plays a role sometimes were it agreeably probably shouldn't.  However there are dozens of types that I have multiple versions of that do, in fact, sound a bit to even a lot better than my commercial pairs.  I have found that the sound of the militarized versions can be more detailed, but also sound a bit more solid state at times; they were often the cream of the crop and are known for being more rugged and having better lifespans, in addition to going through military grade testing before the original sale.  Whereas both the age of the tube and the resulting sonic superiority generally is more specific to the manufacturer/type and over the span of production.  During the late 70's and 80's, the quality of many manufacturers everywhere went down a bit, but those in Russia were actually not too bad during that time.  Like most things, it's a mixed bag of complexity.  I do actually like the later production, 1980's Japanese Mullard EL34s, which can be found cheaper, but they just don't have the tube like tone of the originals, nor the sound-stage.
  
 Welcome to the interesting, but often very complex and frustrating world of tubes!


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## jamespineapple

Hello fellow TU-8200 owners!
  
 I wanted to chime in at Victor’s recommendation with my experience building this amplifier.
  
 As I live in Vancouver, Victor suggested I visit his home to check out the kit before I purchased it.  He was so helpful in explaining the process and even gave me a few additional upgrade components!  We spent plenty of time at his place rolling through some different tubes as well – I got to listen to some Tung-Sol 5881s, PSVane KT88s, and even the holy grail RCA 6L6GCs.  The RCAs blew me away with bass extension and treble clarity – they sounded perfectly flat, very smooth, very responsive.  I felt a bit like I had gone back in time.  It was an incredible experience. 
  
 I was originally planning to use a set of Winged C 6L6GCs in my build, but after the comparison at Victors place I knew I had to go another way. 
  
 The kit came together quite easily – Instructions were easy to follow and I had the whole thing assembled after about 8 hours of work.  I’ve spent the past 3 weeks burning it in and it sounds better every day!
  
 The tubes I ended up settling on in my amp are a pair of PhilipsEGC 6L6GCs and a pair of RCA cleartop 12AU7s.  I find the Philips a little thicker sounding than Victor’s RCAs, but very similar in terms of bass extension, midrange detail, and responsiveness.  The brightness of the cleartops seems to balance them out and adds a little bit of clarity and tightness to the equation.  I tried some Sylvania 12AU7As as well as the Shuguangs that come with, and found that both sets tended to double up the low-mids from the power tubes.  With the Winged Cs, which reminded me of Victor’s Tung-Sol 5881s in their mid-forward response, the Sylvania preamp tubes were a fair compliment but overall I liked the Philips/RCA combination better.  
  
 The only downside is that I had to pull my Philips tubes from my guitar amp, a vintage Magnatone 460, which sounds nice with the Winged Cs but some of that magic warmth is gone. 
  
 I’ve been using my TU-8200 in pentode operation, primarily with my Technics 1300 through a Boozhound Labs Phono pre that I also built.  Speakers are yet to come for me, as I’m in a tiny Vancouver apartment!  I have a set of AKG K702s that make me happy – as someone with a background in audio engineering I prefer a more clinical sound, and as someone who is more into jazz I also appreciate the mellow bass response so many people dislike about these cans. 
  
 I have to commend and thank Victor again for all his help!  I was blown away by his hospitality and his suggestions really helped me with the build.


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## Effusion

Hi jamespineapple,
  
 Thank you for sharing your experiences with Victor and I completely agree about his interest, helpfulness, and customer service regarding these kits; absolutely world-class guy all around.  I'm also glad the build went well and that you are enjoying the sound from the Elekit!  It is truly a great DIY amplifier.
  
 I think you'll find that this amplifier has amazing versatility and will match to many different headphones and tastes.  The type/make of tubes you choose can/will also make significant changes to the sound signature.  Many of the posters here have had a ton of experience with different types of tubes in this amplifier, so please don't hesitate to ask if you find you want something more out of the Elekit.  Since you like a more clinical sound without a whole lot of bass emphasis, I think the 6L6GCs are a pretty good choice.  Ultimately a good pair of RCA "black-plate" 6L6GCs may sound the best to your ears, but you may also want to try some GE 6L6GCs, as I've found them to be a little warmer and fuller in sound, plus they can be found pretty cheap.
  
 Other than the 6L6GCs, the KT88s may also work well for you, however they are a little, to a lot, more expensive and generally have more low-end weight.  A pair of Telefunken EL34s may also be a good choice, but they are hard to find and can be very expensive.
  
 Congrats on the build and welcome to the club!


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## JK-47

Welcome jamespineapple !!!
  
 I also picked up my kit directly from Victor at his house last December. He was awesome to deal with, and has always been very helpful  responding to questions very very quickly.
  
 Some of my favorite power tubes are the Philips 7581A or the GE 7581A (both militarized versions of the 6L6GC). I took Effusions advice and tried vintage GEC KT66's and they are extremely nice, but pricey.
  
 Input tubes... I'm a fan of Amperex.I have a pair of 7316's in right now, and they are sweet. Different power and input tube combo's yield some really amazing results. Some pair beautifully with each other, and not so much with others.
  
 I was born and raised in Vancouver, but the dreaded "Vancouver apartment" pricing and the endless rain drove me to the eastern foothills of the Rocky Mountains... I still think Vancouver is one of the most beautiful cities in the world during summer...
  
 Keep us all posted on how things progress


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## lucidreamer

Welcome to the Elekit club Jamespineapple!!! Hope you enjoy your new Elekit TU8200DX amplifier for a long time and thanks for sharing your experiences with us.
  
 As for power tubes - I would suggest NOS EL34 Mullard XF2 (with either dual or single getter "O" rings, they all sound the same to me). If you like sweet mellow tubey sound with great bass and detailed smooth highs - Mullard EL34 is the way to go. Those true Mullard vintage tubes are fantastic and are by far my favorite tubes for all kinds of music. They can still be found NOS on eBay at great prices if you are patient or from reputable sellers online (costing more $$$ than eBay). I have Psvane MKII KT-88 too but prefer Mullards for both headphone and speaker setups.
  
 For input pre-amp tubes - consider Westinghouse black plate 12AU7. They sell on eBay under CONN or other label and are real secret audiophile gems for a low price. I prefer them to a $100 Psvane MKII 12AU7 anytime. Westinghouse tubes sound more open and cleaner with more bass.
  
 For speakers - you may also consider a DIY kit with full range drivers such as Fostex, Audio Nirvana, etc. I believe that the full range drivers are the best for tube amplifiers because they sound more natural and no energy is lost on crossover resistors, coils, capacitors, etc. I just put together a small set of speakers from Madisound Speaker store consisting of two 4" full range Fostex  FE103-SOL Limited Edition Drivers and am pretty happy with the overall setup (see the picture). It really sounds very natural and sweet at moderate levels especially for acoustic music but still a little harsh when pushing the volume up a little bit. That should resolve with more break-in time, those drivers take a long time to break-in but it is worth it! A small subwoofer helps with low notes tremendously, since those speaker cabinets are tuned to 100Hz, noone can bypass the laws of physics. I also put more damping material inside the speaker cabinets(it lacked some of that stuff) and did small tweaks to the drivers too to reduce the sound reflections inside speakers, the difference was huge! Because I had to choose small speaker size cabinets to fit everything on the A/V cart for my audio setup it did need a subwoofer but a bigger folded horn cabinet can be considered for standalone setups without subs. There are great reviews about  Fostex FE206En full range speakers that rival the speaker sound costing tens of thousands!!!  Fostex FE206En full range speaker is considered as one of the best full range drivers and should work great with Elekit in UL or Pentode mode. I may create another setup later in the living room using bigger Fostex speakers with folded horn cabinet designs. They should not need any subwoofer and the price tag would be around $600-700 for everything.


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## JK-47

Here's a re-post of my Fostex 168EZ 's in madisound folded horn enclosure's. They sound fantastic, and can play loud and accurate when I choose to pump up the volume. For the most part the volume rarely climbs past 10 o'clock and they are very nice and smooth sounding. I originally had the Fostex FE166En (slightly lacking in the treble, and I was considering a Fostex super tweeter), then decided to upgrade the whole driver (on another forum, a fellow had the same drivers then upgraded to the EZ sigma's, and felt the super tweeter wasn't necessary). I would say the Fostex EZ Sigma drivers are worth the extra expense. The angled stands are almost a necessity if you want to hear the low end with any authority. They truly came alive when angled up to ear level.


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## lucidreamer

> ... there will be no surprise to see these tubes popping up for sale again in the near future only making eBay an even worse place for audiophiles. Caveat Emptor!


 
 Just like I thought these tubes are up for sale again on eBay and the seller mentions me as a "recent scammer" only because I returned the tubes that blew my amplifier:
  
 http://www.ebay.com/itm/6CA7-EL34-Mullard-xf1-Matched-Pair-Dynaco-Marantz-HH-Scott-EICO-Fisher-/252027501568?pt=LH_DefaultDomain_0&hash=item3aae027c00
  
 Just wanted to advise everyone to think twice before purchasing anything from this eBay seller *anthonybrian23*


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## 430011

I've been absolutely loving my TU-8200 with Sennheiser HD-650's lately. Listening back to back I prefer the more "full" sound of the 650's over my 600's with the Elekit. I've found my preference is for EL-34 tubes, just a pair of Electro Harmonix. I don't have the budget to try the NOS tubes. 

I've also been pretty happy with the amp driving less sensitive bookshelf speakers. I had a pair of Paul Carmody Speedster speakers that played loudly enough for me in a smaller apartment. But I listen quietly. If I need more volume I switch to headphones. Haven't tried the amp with any single driver speakers. I'm sure that pairing is nice.


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## lucidreamer

430011 said:


> I've also been pretty happy with the amp driving less sensitive bookshelf speakers. I had a pair of Paul Carmody Speedster speakers that played loudly enough for me in a smaller apartment. But I listen quietly. If I need more volume I switch to headphones. Haven't tried the amp with any single driver speakers. I'm sure that pairing is nice.


 
  
 Just wondering how would Speedster speakers compare against MartinLogan Motion LX16. They are basically in the same price range, since Speedster kit is over $300 plus cabinets and LX16 are the older model of MartinLogan 15 (only cosmetic difference) and sell for much less these days:
  
 http://www.crutchfield.com/S-y6BOb1JX57p/p_839MLX16GB/MartinLogan-Motion-LX16.html?o=undefined&tp=186&nvpair=FFBrand%7cMartinLogan&#customer-reviews-tab
  
 I believe LX16 should probably be an overall better sounding factory speaker since they have a bigger woofer (5.25" vs 4") and more frills and gimmicks like motion folded tweeter, precision crossover and so on. I have not listened to them yet, probably will stop by some BestBuy who carry them one day. 
  
 There are of course other great brands, such as Monitor Audio (I have bronze-II floorstands which are great), KEF, B&W, etc.... But it looks like there are people like me who just prefer full-range drivers to any ###-way design for speakers.


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## 430011

Lucidreamer-
  
 I'd be interested to listen to them side by side. I've only heard the Motion 15's for a brief amount of time, but I thought they sounded nice. The cabinets are definitely very attractive and hard to match easily with DIY. I'd probably snatch up a pair of the Martin Logans if there was a smoking deal on them.
  
 That said, I did really love my Speedsters. They produced more bass than I was expecting and it sounded tight. I actually sold them though to help fund my build of Carmody's Carreras. I really like the way he voices his speakers, and I'm thinking the Carreras will be a good long term speaker for me. Although for all of us into DIY it is hard to say any one thing we build will stick around very long. I'm about to wrap up that particular build. I'm worried the TU-8200 won't quite have the drive for them, but I really do listen to my speakers fairly quietly. Small apartment life.


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## lucidreamer

Thanks Evan99. Please keep us posted on the Carreras progress and how these speakers pair with the Elekit amp. I think if you switch the jumpers to Pentode mode and use KT88 tubes in this amplifier it should suffice driving them with 10 watts of pure Class A output. Should be plenty of wattage to drive any smaller speaker at decent level. I should also try to hook up my Monitor Audio bronze ones (rated 100w) to Elekit someday, but they are pretty heavy with sand-filled cabinets standing on the 1st floor.


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## Effusion

Welcome to the club Evan99!  I'm glad things have gone well and that you are enjoying the sound of the Elekit!  The EL34 tubes are very nice indeed, however you are correct, the older/NOS versions can be quite expensive.  You may like the SED Winged "C" EL34, which can be found a little cheaper, but are also becoming rarer every day.  Other than those I really like the Mullard and Tesla EL34s old stock the best.
  
 Thanks for sharing some info regarding different types of speakers you've used with the Elekit (lucidreamer as well).  It would be beneficial to get more one-on-one accounts of this amplifier with different speakers as well as to see how well it pushes them all.  I agree, single-driver speakers, when implemented right, can sound absolutely amazing and are probably the closet thing to headphones as far as speakers go, since the sound originates from a single source/point.  However, they can be quite more finicky about placement and amplification than most crossover designs.  Single drivers is where I'll go eventually, but my speaker listening is still just a little limited right now.
  
 Keep us up to date on how things progress!


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## lucidreamer

NOS Mullard EL34 are very sweet-sounding tubes indeed and cost more than the new ones. The more recent single-getter XF2 or XF3 can still be found NOS for much less than XF1s or XF2 double-getters. I have a pair of used double-getters (my current use) and another pair of NOS single-getters Westinghouse-labeled XF2 which I got for a great deal on eBay recently (grabbed last pair from the seller). They both sound the same to me, I would not be able to tell the difference between them in the blind test, but double-getters are considered to be older and better-made, therefore more valuable to collectors driving the prices higher. Would be also great to compare XF3 and some Holland-made XF4 with DD-getters, some consider them to sound more dynamic and interesting than Mullards.
 Probably =C= EL34 and Groove Tubes EL34 are the best closing match for NOS EL34 as some people recommend those. I originally ordered the pair of new Svetlana =C= EL34 for around $100 and then cancelled the order considering the NOS route instead. For a serious listener it may be worth paying twice more for a pair of NOS EL34 if a deal is available, I think $400 for a pair of NOS EL34 is a lot. But all the new production tubes that I purchased earlier are resting in their boxes at the moment.
 I just won a pair or used but still great GE 6L6GC on eBay today and am looking forward to compare them with EL34 on the Elekit. Maybe GE 6L6GC will be my next favorite ones.


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## 430011

I'm definitely considering the SED winged "C". Maybe even the Gold Lion KT77. I'm tame when it comes to tube rolling.
  
 I was able to attend the Seattle Head-Fi meet this weekend and I've got to say, I truly like the HD-650/Elekit pairing. Most of the solid state amplifiers just struck me as too "sharp". If that means anything, haha. I did listen to a Decware/HD-800 pairing that was extremely nice, but budgetary restrictions really just make that too much of a stretch. Apart from that I find I am generally disappointed with planar magnetic headphones. I owned HE-400's and have now listened to 500's and LCD-2's and they just don't "do it" for me. With the 650's and tubes I can put music on, close my eyes and just get sucked in. Oddly enough, I attended a meet and came away NOT wanting to spend more money! It was a great time though.


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## JK-47

lucidreamer said:


> NOS Mullard EL34 are very sweet-sounding tubes indeed and cost more than the new ones. The more recent single-getter XF2 or XF3 can still be found NOS for much less than XF1s or XF2 double-getters. I have a pair of used double-getters (my current use) and another pair of NOS single-getters Westinghouse-labeled XF2 which I got for a great deal on eBay recently (grabbed last pair from the seller). They both sound the same to me, I would not be able to tell the difference between them in the blind test, but double-getters are considered to be older and better-made, therefore more valuable to collectors driving the prices higher. Would be also great to compare XF3 and some Holland-made XF4 with DD-getters, some consider them to sound more dynamic and interesting than Mullards.
> Probably =C= EL34 and Groove Tubes EL34 are the best closing match for NOS EL34 as some people recommend those. I originally ordered the pair of new Svetlana =C= EL34 for around $100 and then cancelled the order considering the NOS route instead. For a serious listener it may be worth paying twice more for a pair of NOS EL34 if a deal is available, I think $400 for a pair of NOS EL34 is a lot. But all the new production tubes that I purchased earlier are resting in their boxes at the moment.
> I just won a pair or used but still great GE 6L6GC on eBay today and am looking forward to compare them with EL34 on the Elekit. Maybe GE 6L6GC will be my next favorite ones.


 
  
  
 Don't over look the GE 7581A's either, they are virtually the same as 6L6GC's. I scored 5 of them a few weeks ago for $120 shipped. A better deal than most GE 6L6GC's by far, sometimes they can go for several hundred $$$ for a matched pair. 3 of mine tested almost NOS on my Maxi-Matcher, and the other 2 were not far behind. Still my number 1 tube right now is the Philips 7581A.... Clean. tight and punchy. I've hoarded a lot of both, so you probably won't be bidding against me


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## lucidreamer

Thanks JK-47. I did some reading and looks like 7581a tube is a great tube but also hard to find NOS or costing at least the same or more than regular 6L6GCs. These 7581a tubes are designed for audio applications and run hotter than 6L6GCs (35W vs 30W). I should receive my GE 6L6GC tomorrow or so, I cannot wait to compare the NOS 6L6GC to my EL34 and see which one sounds better for me. I really enjoy my Mullard XF2 EL34 at the moment paired with 4" Fostex full-range speakers (Anniversary Limited model). Those speakers are eventually breaking in now and I think they are pretty good in reproducing the tiny nuances and details that I did not notice before. The high-end is not recessed and extends to 40k or something based on their datasheet. I do not see any need for an extra supertweeter for them, they just sound right for me with very natural, sweet and realistic touch, maybe they are not that great for loud volumes because they are only 4" in size they are still perfect for moderately loud volumes in smaller rooms.
  
 I am actually interested in buying a pair Philips 7581a tubes in the future, looks like they (and RCA 7581a too) are among the best 7581a. Philips was designed for military use with some extra plating to extend the lifetime of the tube compared to other brands. Since this is your #1 choice based on you previous post - how does it sound compared to the GE NOS 6L6GC for instance? I am just curious whether the difference makes the sound more 'solid-state' and too punchy losing that tubey sweet character that Mullard EL34 has.
  
 Is the JAN *7027A *same tube as 6L6GC/7581a too or different? I read some great reviews about them.
  
 These tubes are basically the same as 6L6GC internally where 6L6GC does not use Pin #1 and #6 and the 7027A duplicates Grid #2 on Pin 1 and Grid #1 on Pin 6. On the amplifier schematic - Pin #6 is not used at all but Pin #1 is in shown in brackets and linked to the ground, not really sure what that means by brackets (maybe just optional tube pinout connections).
  
 Any possible suggestions if 7027A are safe for this amp?


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## JK-47

lucidreamer,
  
 Philips 7581A: are virtually the same structurally as Sylvania 415 STR (6L6GC) and Sylvania 387 STR (6L6GC). Philips bought Sylvania USA's tube production in the 1980's.
  
 RCA 7581A: Made by GE, the signature GE dot date code and internal structure proves this. So I wouldn't expect them to sound any different than GE's 6L6GC/7581A.
  

  

  

  
  
 GE 7581A: interior structure identical to later production GE 6L6GC tubes, but the plate current always reads higher on my  Maxi-Matcher apprx 30mA vs 20mA. I believe this to be due to the higher power rating 30W vs 35W.
  
 Also search for Vacuum Tube Valley and download the issues in  PDF... issue #4 and #13 test the 6L6 family. issues #2 and #16 test the EL34 family, and the KT88 family is discussed in other issues.


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## lucidreamer

Thanks JK-47! Cool information!
  
 I think 7027A cannot be used in this amplifier, at least not without cutting off Pin #1 from the tube which may or may not work well anyways. 
  
 Based on the Elekit schematic Pin #1 and #8 are jumpered which is needed for EL34. 6L6GC does not use Pin#1 which has no effect on that bridge (for EL34). If I plug in 7027A into the socket many things can happen, including burned resistors, transformers, tubes, etc. Not worth risking another repair, I guess. Those tubes are different.
  
 Some online information on comparing EL34 and 7027A tubes and possible swapping:
  
*From http://www.triodeel.com/7027.htm:*
  
*Q.What about EL34's?*
 A.Simple. Install a jumper between pins 1 & 8 on the tube socket. However, do *NOT* attempt to use 7027 after you've installed that jumper! Some folks who've used EL34's in these amps say they get better tone out of them by installing a variable bias control (the stock bias voltage on most Ampegs that use 7027, is a bit lean for EL34's), and by changing the screen resistors to 1,000 ohms instead of 470 ohms. 
 Note that a few of the early V-series Ampegs had no screen resistors at all! Unless you plan on going back to to 7027's (which you can't with the pin 1 to 8 socket jumper, anyway), you could install these right on the socket like a Fender or Marshall.
 If you're going to do either of the above, I'd suggest strongly *putting a label on the chassis to indicate that it's wired to use EL34's*, and that 7027 will NOT work.
 If you've made the above changes, you can use 6L6 or 6550 as well, only caveat being that if you've installed an adjustable bias control, you'll want to adjust it when swapping between the various tube types. Installing a 1 ohm resistor between pin 8 and ground for bias metering (eg: 35 millivolts or .035V across the resistor will be 35 ma per tube) makes this procedure easier. 
  
*From http://www.ozvalveamps.org/strauss.htm:*
  
Simply plugging 7027A's into sockets wired for EL34/6CA7's will result in at least burned-out screen resistors and a very quiet amp because the pinout is significantly different.






   
	

	
	
		
		

		
		
	


	



EL34 (left) and 7027A (right). Note the two internal 7027A connections between pins 1 and 4, and 5 and 6.
The EL34 socket will be wired with the cathode and G3 grounded, pins 1 and 8. The 1k5 grid stopper resistor is often wired between G1 and the No Connection pins 5 and 6. Screen volts are connected to G2 pin 4.
When we plug in a 7027A the stopper resistor is bridged by the internal link - not really a problem.
But the internal link from 4 to 1 will ground the screen supply. It's uncertain which will give out first, the screen supply resistors, the power supply, or in the unhappy case it's ultra-linear connected, the output transformer. 
Sometimes we are forced to mod an output stage due to valve type unavailability. Converting 6DQ6 amps to use EL34's is one example.
But this apparent attempt to get more watts out needs more thought than just the base wiring. Apart from the plate-to-plate load impedance, the output tranformer power handling is bound to be exceeded and the power supply strained by any extra demand.
Just because it fits in the socket doesn't mean it's right.


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## JK-47

I would say the Philips 7581A sounds tighter and has more dynamic punch than the GE6L6GC. It by no means sounds solid state, just a touch more refined. Again, it can also depend on the input tubes in the unit. Some tubes have an amazing synergy with each other, while some combos sound dull and dreary.
  
 A common test I implement when testing tubes is one my Dad uses. We use spoken dialogue from a good source, and listen to how natural the speech sounds. How clearly defined each speaker is represented in a busy scene (downtown New York, the beach...etc), Is the speech, sibilant, nasally, muddy, or smooth and effortless. A DVD or Blue-Ray movie provide excellent source material. The other components in the chain such as DAC, headphones/speakers and BR player will have an effect, but if they stay the same and only the tubes are changed, the results usually translate very nicely when selecting tubes for my music (lots of 70-80s Rock, Electronic music from the 80s to present, and lots of other stuff in between).


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## JK-47

lucidreamer,
  
 Thanks for the info on the 7027A, sounds complicated and not really worth the effort to try out in our systems. Great research though, none the less.


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## lucidreamer

I agree, the internal structure in those tubes is the same. But it is the plating material and its thickness, glass bulb volume and other small differences that may make the sound more punchy, tighter and increase the tube's life a little too.


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## lucidreamer

Input tubes are important too, I just got a pair of ECC82 NOS tubes from Bulgaria made by RTF in German Democratic Republic back in the 80's and they sound amazing! Same amount of bass as Westinghouse, very open and detailed sounding input tubes, maybe more punchier than Westinghouse. They were pretty cheap on eBay and are highly-rated online. Looks like German-made tubes are great, I should also try some EL34 by RTF or Siemens, both RTF and Siemens tubes are probably the same thing most of the time anyways.


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## JK-47

lucidreamer said:


> I agree, the internal structure in those tubes is the same. But it is the plating material and its thickness, glass bulb volume and other small differences that may make the sound more punchy, tighter and increase the tube's life a little too.


 
  
  
 My ears tell me the later tall bottle GE6L6GC = GE7581A = RCA7581A, they all sound virtually the same (basically any of 3 shouldn't warrant a"special premium" over the others. The Philips 7581A and their Sylvania STR family are another breed altogether.


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## lucidreamer

jk-47 said:


> My ears tell me the later tall bottle GE6L6GC = GE7581A = RCA7581A, they all sound virtually the same. The Philips 7581A and their Sylvania STR family are another breed altogether.


 
 Correct, I meant the same thing. Philips used more plating and made other changes to the military version of 7581A, therefore, it should sound different. Here is the source page on another forum: http://www.audiokarma.org/forums/showpost.php?p=8622975&postcount=24
  
_Note 2. - There seems to be a military version of the 7581A according to Watford Valves:
https://www.watfordvalves.com/produc...il.asp?id=1317

 From that web site, I don't think that all 7581A's are JAN Military:
 "Philips ECG JAN / 6L6GC/STR387-7581A-PHILIPS
 Philips electronics components group was the name given to the products marketed in America after Philips bought the American valve manufacturer Sylvania in the early 1980’s. Sylvania was a major manufacturer of valves and Philips bought them to get the lucrative American Government and military contracts. These valves are of the highest military grade which offer outstanding performance and were all made in the USA.
 The 7581A is the high grade military version of the famous Sylvania 6L6GC STR 387. The 7581A was made to have a higher plate dissipation of 35 watts, where all other 6L6GC types have a 30 watt rating, Philips Sylvania uprated anode plate coating allowing better heat transfer. The valve also uses the highest grade nickel for the anode plate construction so the 7581A gives a long life."_


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## lucidreamer

I just got a pair of used NOS GE 6L6GC tubes from eBay this morning and dropped them into my Elekit to compare with EL34. Luckily, no smoke, burning smell or even the red light came up which was a good sign especially after recent eBay experiences with vintage tubes.
  
 Well.... I agree with everything that was said in abundance about NOS 6L6GC tubes earlier and they do sound great with a very balanced and full sound overall, however, EL34 is still by far a clear winner for me. That is just my humble opinion, please do not hate me for it, I am not trying to criticize anything, only comparing things based on my personal view and perspective.
  
 These NOS 6L6GC tubes are definitely sounding superior to any other production line that I have tried before. They seem to possess that clean and reference-like tone with great realism, however, EL34 are more pleasant to listen to for me compared to 6L6GC. EL34 have sweeter mids, they sound more laid-back and musical with deeper tone and have that kind of enveloping 3-d soundstage especially when listening with the headphones. The high notes are still there just fine, only sounding more silky-smoother and non-obnoxious, I listened to EL34 for hours in a row without any fatigue. On the other hand, the GE tubes have great balanced realistic sound with perfect bass and highs, but overall they sound kind of flat and two-dimensional to me, lacking some of that laid-back tubey character that EL34 has. I think some people who listen to rock and metal may prefer 6L6GC to EL34 without doubt, but for jazz and acoustic music, the EL34 have that something in them that no other tubes seem to have.


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## lucidreamer

Actually I partially take it back.... I put those tubes into the amp again this evening and let them run for some time prior to listening and they seem to be opening up a little bit with nice tight bass and sweeter tone then before. Maybe more warm up time or a different placement made a difference, hard to tell, but.... Pretty nice tubes those GE 6L6GC, I like them now!


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## Effusion

If they haven't been run, at least at operating levels, for a longer period of time, sometimes it can take a bit of time for them to burn-in, even if they are used.  The GE 6L6GCs are nice, especially for the price, but I agree the Mullard EL34s sound better overall and in many different ways.  The GEs are no slouch though if you are able to score a good pair.  I have noticed some variations between a few of them and as JK has noticed, the different military types are many and generally sound very nice.
  
 I agree about the 12au7s and the difference that they make; it's not always that subtle and at times can really surprise me.  I still find that switching between different types, such as between EL34s, KT88s, and 807s, usually provides a more pronounced difference, however I recently acquired a very cheap pair of Westinghouse 12au7 gray round plates with single halo getters that sounds absolutely amazing with my Genalex Smoked Glass KT66s.  I'm mean really good in so many ways and even compared to some other very nice and expensive pairs.  The real crazy thing is they are actually re-branded GE's!
  
 They have the classic GE stamp and circle pattern near the back.  You can also tell that the orange re-branded logo was stamped post production and quickly... these really surprised me!  This wasn't the first time a 12au7 has surprised me, but they just were not as good as this combo.  Probably some of the best sound I've heard out of this kit for anything acoustic or with female vocals, period.  However, there are still a few genres where the combo lacks a little bit of attack or has just a little too much sound-stage on certain recordings.  I've found that sometimes taking risks and trying off or not too common types can have its benefits.  If you know what to look for, you can get some really nice pairs for cheap, just because they are re-branded or not surrounded by hype.  This isn't always the case, as some I've acquired haven't sound that great, so there's some gamble and it is still a risk.  Several guitar amplifiers did use these variants while they were still being produced and some of these companies many times required certain specifications for sound as well as undergoing a higher degree of testing in general; after all, many times the smaller companys' production weren't just going into mass produced TVs, etc.
  
 Thanks to all for the breakdown of the 6L6GC and variants; there are still a few that I haven't tried, and really need to.  I found this very informative as well as helpful.  I may have some questions as I think I might finally try a few different pairs very soon...


----------



## Effusion

Correction to above, really more of an additional observation... the Westinghouse rebranded GE 12au7 I just acquired are actually 5814a's, a 12au7 substitute.  It is very faintly stamped by GE and next to the dots on the back of one tube.  Other than that they are the same date code and tested very high and pretty close, but by looking at the pins, they are at least a little used.  Very nice pair and better overall than my other 5814s; it might be hard to find more of them since they are a rebrand, etc. though.
  
 Compared to my excellent sounding Siemens 5814a, these seem to have a fuller sound, a bit more warmth, and a little closer, but different, sound-stage.  While I've found the Siemens to be very detailed/open and at the same time still quite smooth, they are not as smooth as these rebranded GEs.  I can see both being very good choices for different types of genres and moods.  They also both sound very nice with a few KT-88s I've tried, in addition to my smoked glass Genalex KT-66.  Unfortunately I haven't tried this new pair in other combos yet, but I'm planning to soon.... a very nice unexpected surprise indeed!


----------



## 430011

A bit off the current topic:
 I know it has been discussed before, but what is the consensus on adding ventilation to the case of the amp? I was thinking of drilling a pattern of small holes in the case in the space just behind the 12AU7 tubes and around the octal sockets. It seems to be the hottest part of the case. Then drilling holes or using perforated aluminum sheet in the bottom of the case to allow convection heat loss. Would there be a negative impact on RFI rejection? it seems unlikely that would be a significant concern.
  
 Generally the amp doesn't get too hot during normal outside temperature days and I don't think about it. However, here in western WA we have been experiencing some 90+ days which means a very warm living room since A/C isn't really a thing here. On those days the amp case gets very hot indeed. sometimes I'll run a small computer case fan on it, but I don't love that solution. I know that class A tube amps run hot, but this is bordering VERY hot. Thanks!


----------



## lucidreamer

430011 said:


> A bit off the current topic:
> I know it has been discussed before, but what is the consensus on adding ventilation to the case of the amp? I was thinking of drilling a pattern of small holes in the case in the space just behind the 12AU7 tubes and around the octal sockets. It seems to be the hottest part of the case. Then drilling holes or using perforated aluminum sheet in the bottom of the case to allow convection heat loss. Would there be a negative impact on RFI rejection? it seems unlikely that would be a significant concern.
> 
> Generally the amp doesn't get too hot during normal outside temperature days and I don't think about it. However, here in western WA we have been experiencing some 90+ days which means a very warm living room since A/C isn't really a thing here. On those days the amp case gets very hot indeed. sometimes I'll run a small computer case fan on it, but I don't love that solution. I know that class A tube amps run hot, but this is bordering VERY hot. Thanks!


 
  
 I also considered adding a silent fan on top of the case but then discarded the idea since any fan would introduce noise and I often listen to the music at low volumes. I do not know if there are any tube amplifiers with open tube design that have cooling fans.
 You may consider using a pair of socket savers for the power tubes as I did. they have no effect on the audio quality. Hard to believe but it does reduce the overall temperature of the metal case a little bit because the heated glass bulb is risen about an inch from the top plate and tubes stay cooler too. I could tell the difference by touching the bases of the tubes before and after installing the socket savers.


----------



## lucidreamer

Just arrived a pair of Philips 7581A NOS tubes that I got on eBay lately and these tubes are built like tanks and just ooze quality! They are bigger than GE 6L6GC too and the connectors inside are pretty solid and thick, real MIL-spec type of equipment. I put them in and the sound struck me as super-clean and detailed, the highs are very articulate and pronounced and the bass feels very tight, probably the best I ever heard in a tube amp. Now I understand why many recommended this tube for bass amps especially. I think I will stick to that tube for a while, just want to see if the sound will mellow out a little bit during the break-in, the highs seem to be on the border of fatiguing at times especially with the Fostex speakers (up to 40kHz driver range). If listening for that kind of sound will prove to be fatiguing after several hours, I will probably put them in the drawer or sell them later. What is funny is that those tubes were so abundant before and in the 60-70's they were sold for a penny, something like 2-5 bucks each. These days they are sold for $120 each in stores.
 But so far - pretty happy with that tube overall! Thanks for your recommendations guys, really appreciate it!


----------



## JK-47

Thanks for the tube updates Efussion and lucidreamer,
  
 I'll have to try me GE 5814's again soon. I haven't had then in in months. It's mostly been the 6189 Philco/Lansdale's (more detail and resolution), and Amperex 7316's (warmer midrange and holographic soundstage) lately...
  
 I have some Philips input tubes on the way, and will fill you guys in on the sound when I get home from work in 3 weeks...
  
Blue 6189's and Green 5814's
  
 lucidreamer,
  
 Like all tubes, sometimes they need time to settle or different paring on the input tubes to tune the sound slightly. My critical tube listening is always done with headphones, so I'm sure to have the whole frequency spectrum represented. That might be hard to do with small full range speakers.


----------



## catcherfly

Hi All,

I am looking to buy some RCA 12AU7A Clear tops and a pair of power tubes. Currently I am running Philips 7581A 6L6GC and Amperex 12AU7 Orange Globe tubes in Ultralinear mode. Do any of you have suggestions for other power tube options to try out? 

Here is a link for some Clear Tops. Any thoughts on these? They are from the 70s and I don’t know if the Clear tops are still worth it post 60s. http://www.ebay.com/itm/RCA-12AU7A-ECC82-Clear-Top-Tubes-Matched-Pair-Tested-NOS-NIB-Matched-Codes-/261962447366?pt=LH_DefaultDomain_0&hash=item3cfe2dba06

Any thoughts would be greatly appreciated!

After 20 years as an artist I have decided to open an audio equipment, audio furniture, and record store (web and retail) in Portland Maine. The TU-8200 has had a lot to do with this choice! I am trying to finish up some prototypes in the next few months including a turntable, a line of Rock Maple furniture, a line of speaker cabinets with Audio Nirvana drivers, and a speaker/subwoofer selector box. For now I am using my home as a showroom and I’ll post some high quality pictures when I install the Maple equipment/record units and the finished speaker/sub selector box. In the meantime, here are a few pics and videos!

Thanks,
Joe








[VIDEO] IMG 0914 from K|M|A on Vimeo.
[/VIDEO]

[VIDEO] IMG 0470 from K|M|A on Vimeo.
[/VIDEO]

[VIDEO] IMG 0866 from K|M|A on Vimeo.
[/VIDEO]

[VIDEO] IMG 0719 from K|M|A on Vimeo.
[/VIDEO]


----------



## JK-47

Nice set up catcherfly


----------



## catcherfly

jk-47 said:


> Nice set up catcherfly


 
Thanks JK-47!

I am continually amazed at how good the TU-8200 sounds. I have two pairs of speakers hooked up to the 8200 and it effortlessly fills the entire apartment. I have also stopped listening to my HE-400i through my Audio-GD balanced headphone amp in preference for the 8200. 

Can anyone recommend a store or reliable eBay seller for tubes? After hearing Lucidreamer's, and other's, stories I am a bit nervous, especially without a tube tester. 
And again, can anyone recommend some power tubes? I am currently running Philips 7581A 6L6GC with Amperex 12AU7 Orange Globe.

Thank you!


----------



## lucidreamer

catcherfly said:


> Can anyone recommend a store or reliable eBay seller for tubes? After hearing Lucidreamer's, and other's, stories I am a bit nervous, especially without a tube tester.
> And again, can anyone recommend some power tubes? I am currently running Philips 7581A 6L6GC with Amperex 12AU7 Orange Globe.


 
  
 Hi Catcherfly!
  
 Congratulations on the Elekit setup, looks really nice with Nirvana Audio speakers! The full-range speakers with Elekit tube amplifier is a match made in heaven! 
	

	
	
		
		

		
		
	


	



  
 As for the power tubes - It really depends what kind of sound you are trying to pursue. I would say that Philips 7581A that you already have is one of the best NOS tubes out there for me. I currently use these tubes too since last week as they were brand new when I bought them and now just keep opening up terms of the sound. Really clean and tubey sound that they output. I even noticed that they starting glowing blue much more now than they did when I just put them in in the first day. The same blue glowing starting showing with my other TAD new production 6L6GC tubes after they burned in a little bit, so it must be  a good indication of new tubes. 7581A have the best bass sound for me compared to other tubes.
  
 Another great NOS choice, if you prefer a little warmer and laid-back British sound is EL34 but they are harder to come by in NOS state, especially XF1 or XF2 made by Mullard Blackburn factory. I have only listened to XF1 and XF2 double and single getter ones but other NOS EL34 are supposed to be great as well, there is lots of information about them on the internet. If you are looking to buy EL34 - I would recommend http://www.cathedralstone.net/Pages/MullardEL34finalm.htm, Michael really knows his stuff and can help you with your tube selections.
  
 For the input tubes - I really dig the RFT 12AU7 ones. Westinghouse black plates are great too with very open and spacious sound but RFT sound cleaner and more dynamic. There was a site on the internet, I cannot remember which one at the moment, where there was a table comparing the sound character between different 12AU7 brands. I will try to find and post it later. RCA 12AU7 - I read somewhere that it is not as good as Westinghouse, but they could be different tubes too.
  
 Please keep up posted on your experiences with tube rolling, etc.


----------



## JK-47

catcherfly said:


> Thanks JK-47!
> 
> I am continually amazed at how good the TU-8200 sounds. I have two pairs of speakers hooked up to the 8200 and it effortlessly fills the entire apartment. I have also stopped listening to my HE-400i through my Audio-GD balanced headphone amp in preference for the 8200.
> 
> ...


 
  
 Hmmm... a reliable ebay seller... that can be a tough one. Originally I looked at buying tubes in a few ways; pay a premium and buy from a few online retailers that claim they test and match etc. , roll the dice on ebay, buy a tube tester or testers and know 100%  that I was getting what I was paying for. In some case I have had to send replacement tubes back to the seller, and have heard almost every excuse in the book.
  
 I will say that my testers have already almost paid for themselves in the span of less than a year (my 2 new testers have, but not my vintage Hickok yet). They have enabled me to return duds, non matched pairs, and micro-phonic input tubes, with little or no argument from the seller. Almost 1 out of 3 sets of vintage tubes I buy have problems or are not as advertised, not too mention I can buy single tubes and match them myself. I prefer the term vintage when talking about older tubes, I feel "NOS" (New Old Stock) is grossly over used and misleading. Very few old tubes are actually untouched and mint...
  
 In the end it's up to you. The world of tubes is very murky, but oh so rewarding


----------



## catcherfly

lucidreamer said:


> Hi Catcherfly!
> 
> Congratulations on the Elekit setup, looks really nice with Nirvana Audio speakers! The full-range speakers with Elekit tube amplifier is a match made in heaven!
> 
> ...



Thanks a lot for your suggestions Lucidreamer. I will definitely spend some time on the Catherdral Stone site


----------



## catcherfly

jk-47 said:


> Hmmm... a reliable ebay seller... that can be a tough one. Originally I looked at buying tubes in a few ways; pay a premium and buy from a few online retailers that claim they test and match etc. , roll the dice on ebay, buy a tube tester or testers and know 100%  that I was getting what I was paying for. In some case I have had to send replacement tubes back to the seller, and have heard almost every excuse in the book.
> 
> I will say that my testers have already almost paid for themselves in the span of less than a year (my 2 new testers have, but not my vintage Hickok yet). They have enabled me to return duds, non matched pairs, and micro-phonic input tubes, with little or no argument from the seller. Almost 1 out of 3 sets of vintage tubes I buy have problems or are not as advertised, not too mention I can buy single tubes and match them myself. I prefer the term vintage when talking about older tubes, I feel "NOS" (New Old Stock) is grossly over used and misleading. Very few old tubes are actually untouched and mint...
> 
> In the end it's up to you. The world of tubes is very murky, but oh so rewarding :evil:



Thanks JK-47! Is there one modern tube tester you would recommend?


----------



## catcherfly

jk-47 said:


> Hmmm... a reliable ebay seller... that can be a tough one. Originally I looked at buying tubes in a few ways; pay a premium and buy from a few online retailers that claim they test and match etc. , roll the dice on ebay, buy a tube tester or testers and know 100%  that I was getting what I was paying for. In some case I have had to send replacement tubes back to the seller, and have heard almost every excuse in the book.
> 
> I will say that my testers have already almost paid for themselves in the span of less than a year (my 2 new testers have, but not my vintage Hickok yet). They have enabled me to return duds, non matched pairs, and micro-phonic input tubes, with little or no argument from the seller. Almost 1 out of 3 sets of vintage tubes I buy have problems or are not as advertised, not too mention I can buy single tubes and match them myself. I prefer the term vintage when talking about older tubes, I feel "NOS" (New Old Stock) is grossly over used and misleading. Very few old tubes are actually untouched and mint...
> 
> In the end it's up to you. The world of tubes is very murky, but oh so rewarding :evil:



Victor recommended the Genalex Gold Lion KT88 as an affordable new option. Does anyone have experience with this tube? The Tube Store is one source. Have any of you purchased from them?


----------



## mhamel

catcherfly said:


> Victor recommended the Genalex Gold Lion KT88 as an affordable new option. Does anyone have experience with this tube? The Tube Store is one source. Have any of you purchased from them?


 
  
 I've been running the new release Genalex Gold Lion KT77 the past couple of months and have been really happy with them. Jim McShane sells them at a good price with a great warranty.
  
 I'm using Sylvania 12BH7 as the input tubes, but the heater circuit for the preamp tubes in my amp has been upgraded to handle the additional current these draw.


----------



## JK-47

For testers I use a Maxi-Pre Amp 2, and a Maxi-matcher 2. Be warned though, the measurments will not coincide with Hickok testers that are used by many sellers on eBay. I use Hickok tested bogey tubes to create a reference for my testers. 

The Amplitrex is another reference tester that many eBay sellers use. It cost more than the Maxi products, and has a may not be in Stock.

Space tech makes a few digital testers, but have not heard anything regarding their performance. 

I like my Maxi's, they are awesome for matching and telling me if a tubes are bad. 

In the end it doesn't seem there is one end all, be all answer to tube testers. Each one has there pros and cons...


----------



## catcherfly

jk-47 said:


> For testers I use a Maxi-Pre Amp 2, and a Maxi-matcher 2. Be warned though, the measurments will not coincide with Hickok testers that are used by many sellers on eBay. I use Hickok tested bogey tubes to create a reference for my testers.
> 
> The Amplitrex is another reference tester that many eBay sellers use. It cost more than the Maxi products, and has a may not be in Stock.
> 
> ...


 

 Thanks JK-47! I look forward to checking out the Maxi's and the others you mentioned


----------



## catcherfly

mhamel said:


> I've been running the new release Genalex Gold Lion KT77 the past couple of months and have been really happy with them. Jim McShane sells them at a good price with a great warranty.
> 
> I'm using Sylvania 12BH7 as the input tubes, but the heater circuit for the preamp tubes in my amp has been upgraded to handle the additional current these draw.


 

 Hi Mhamel,
  
 I ended up buying Genalex Gold Lion KT77s and Genalex B749/12AU7s from Jim McShane.
  
 Thanks for your recommendation!


----------



## JK-47

catcherfly said:


> Victor recommended the Genalex Gold Lion KT88 as an affordable new option. Does anyone have experience with this tube? The Tube Store is one source. Have any of you purchased from them?


 
  
  
 I have a matched pair, and by all means they are decent. I don't know if it's sub conscious or some special tube magic, but the New Genelex Gold Lion KT88's seem to be missing just a touch of that special something, vintage tubes provide to the sound...


----------



## catcherfly

jk-47 said:


> I have a matched pair, and by all means they are decent. I don't know if it's sub conscious or some special tube magic, but the New Genelex Gold Lion KT88's seem to be missing just a touch of that special something, vintage tubes provide to the sound...



Thanks Jk-47! After I've spent some time listening, I'll post my impressions.


----------



## lucidreamer

catcherfly said:


> Hi Mhamel,
> 
> I ended up buying Genalex Gold Lion KT77s and Genalex B749/12AU7s from Jim McShane.
> 
> Thanks for your recommendation!


 
 The Genalex Gold Lion KT77 should be a great tube, it is a new production EL34 and some people like it more than the famous Svetlana =C= EL34 tube. Would be great to check how it sounds.
  
 Some reviews:
  
 http://www.thetubestore.com/Tubes/EL34-6CA7-Tube-Types/Genalex-Gold-Lion-KT77
  
 http://forums.stevehoffman.tv/threads/anyone-try-the-genalex-gold-lion-kt77-tubes.188183/
  
 http://www.tubesforamps.com/best-el34-tube-review


----------



## catcherfly

lucidreamer said:


> The Genalex Gold Lion KT77 should be a great tube, it is a new production EL34 and some people like it more than the famous Svetlana =C= EL34 tube. Would be great to check how it sounds.
> 
> Some reviews:
> 
> ...


 

 I bought the KT88 not the KT77. Sorry about that!!


----------



## JK-47

mhamel said:


> I've been running the new release Genalex Gold Lion KT77 the past couple of months and have been really happy with them. Jim McShane sells them at a good price with a great warranty.
> 
> I'm using Sylvania 12BH7 as the input tubes, but the heater circuit for the preamp tubes in my amp has been upgraded to handle the additional current these draw.




What parts did you replace to accommodate the 12BH7's?


----------



## LingLing1337

One of my psvane kt88 just blew up! Well it didn't explode, but it died with a flash and a crackle to the speakers. Unfortunate they were a solid 4/5 for sound but for reliability, this puts them at a 1 or 2/5 for me.


----------



## vkung

It depends where you got your psvane and how much you paid..


----------



## lucidreamer

lingling1337 said:


> One of my psvane kt88 just blew up! Well it didn't explode, but it died with a flash and a crackle to the speakers. Unfortunate they were a solid 4/5 for sound but for reliability, this puts them at a 1 or 2/5 for me.


 
  
 Sorry to hear about that... hope that your resistors and FETs are still good?
  
 Just curious... Did you buy them from Grant Fidelity (shipped from Hong Kong) or some eBay seller? eBay have them cheaper but the Grant Fidelity store should be a better choice because they burn in and test them for some time(supposedly), mine have like 30-40 hours and worked great. I just put them away to sell or use later. I would be iffy to get those tubes direct from China, you never know if those tubes are made at the same factory that also makes the fireworks and what they put inside those tubes (just kidding) 
	

	
	
		
		

		
			




  
 My RFT ECC82 preamp tubes are acting up a little strange too. When I turn on the amplifier, they light up pretty bright for a second as if the voltage is higher and then dim out to normal level. Is that supposed to be normal for tubes? Also, I noticed that one of the channels was outputting some excessive noise, I got scared that something could be blown up again. But after I removed the preamp tubes from their socket savers and put them back in without them the noise disappeared. One of the channels still has a slightly higher level of background noise compared to the other one, it is still pretty low and I can only hear it in the speakers, not the headphones, but I think it is normal because some tubes can be noisier than others. Those 8 Ohm Fostex speakers are really sensitive too.


----------



## JK-47

LingLing1337,

Sorry to hear about the blown tube, is your amp OK?

Lucidreamer,

I believe your Rft ecc82 tube is part of the Amperex/Philips family, and they are known to glow brightly for a second when turned on from a cold start. 

The static may be from oxidized pins, give the pins a scrub and cleaning. Also try another set of input tubes and see if the background noise remains.


----------



## Greg70

lucidreamer, yes I suspect the start up flash is normal as JK-47 said.
 The following is about Mullards, but several tube types do this:
  
 The flash occurs on one side of the filament wires between the bottom plate and the inside bottom of the tube and this phenomenon only occurs when powering up from a cold start.   The sudden influx of current on the cold heater filament encounters very little resistance along this wire (hence the sudden burst of light).  So in effect one side of the tube always warms up 1st,  the second takes a while to catch up but before long the heat is evenly distributed (and your amp comes to life).
  
 And this: Many of the Philips family of tubes (Siemens, Mullard, Valvo, Amperex/Miniwatt, even Ei) exhibit this design. The cold, exposed portion of the filament is less electrically resistive, but when it heats up (as it does rapidly), the electrical resistance rises rapidly, stopping the phenomenon.


----------



## lucidreamer

Cool, thanks everyone. I will try to clean the pins again and see if the hiss will go away. I suspect it was a bad connection to the socket saver or some RMI issue caused by using a socket saver in the preamp tube that extended the pins and might have caused some interference issues.


----------



## JK-47

lucidreamer said:


> Cool, thanks everyone. I will try to clean the pins again and see if the hiss will go away. I suspect it was a bad connection to the socket saver or some RMI issue caused by using a socket saver in the preamp tube that extended the pins and might have caused some interference issues.




I edited my earlier post to ask you to try another set of input tubes if the pin cleaning doesn't work...


----------



## LingLing1337

I havent cracked the amp open yet to assess its condition, I just swapped in the backup amp for now. I will say the right side tube, the one that blew, has always lit up more dimly than the left side regardless of the set of tubes


----------



## JK-47

lingling1337 said:


> I havent cracked the amp open yet to assess its condition, I just swapped in the backup amp for now. I will say the right side tube, the one that blew, has always lit up more dimly than the left side regardless of the set of tubes




Did you try another set of tubes to see if it works?


----------



## Effusion

catcherfly,
  
 Congrats on the new venture and keep us all up to date on how it progresses.  I really like your cabinets for single drivers, which is where I'll probably be going in the near future with the Elekit.  Very cool!
  
 As far as tube recommendations, it really depends on where you would like to go, compared to what you have already tried.  I really like the vintage KT66s, but they can be pricey.  Another good option, at least to get a sense, is also the 807s.  They aren't as popular, so prices on vintage pairs are much less, but they sound pretty darn good for the money.  I would say that my favorite pair, smoked-glass JAN Hytrons are between the sound of a 6L6GC and a KT66; they have great tone, resolution and slam, but are just a bit more confined and with less air and finesse than the KT66.  Still very nice indeed, especially for the price, but you'll have to also purchase a pair of adapters in order to use them (just make sure the top pin connection is fairly tight before trying them, I've found that a few of the European 807 variants tend to have smaller top pins, etc.).
  
 LingLing1337,
  
 Sorry to hear about the Psvane tube fail... I'm glad that the amplifier appears to be okay though.  I've also had tubes end their life in my other amps before and they generally behave exactly the way you described above.  Shame that it happened to a Psvane tube, as they are generally regarded as being much better quality than other Chinese offerings.  I've read a ton of threads were those using the Shuguang Treasure Tubes as well as many using the new issue Genalex KT88s have had tube failures within 2 to 4 hundred hours of use.  Not cool when you spend so much on a pair.  Most of the time it appears to happen in guitar amps within a fairly short amount of use, since they just eat up tubes and really put them through the grind.
  
 I really hope you are able to exchange/return the tube that failed and recoup the majority of the cost of the initial pair.  I've always found it interesting that some of the newer production, especially the cheaper ones from China/Russia, have such large fail rates after just a few hundred hours, while the shear amount of vintage tubes I own and put a ton of time on have lasted so much longer without issue.  I think it really comes down to both the materials, but also mainly the manufacturing processes at these plants.  As someone else mentioned, it is wise to buy newer production from shops here in the US that do extensive burn-in and matching prior to sale.  The one shop here locally told me that they have always had huge issues with quality control from both Chinese and Russian plants and when they purchase a pair they are almost never close or matched in output directly from the factory, even though they factory is selling them as perfectly matched "factory" pairs... crazy.  There are several vendors here in the US that take quite a bit of time to try to curb this, if for just a few extra bucks per pair.
  
 Let us know how it all pans out and I wish you the best of luck moving forward.


----------



## catcherfly

effusion said:


> catcherfly,
> 
> Congrats on the new venture and keep us all up to date on how it progresses.  I really like your cabinets for single drivers, which is where I'll probably be going in the near future with the Elekit.  Very cool!
> 
> ...




Effusion, thanks so much for the tube suggestions, I really appreciate it!


----------



## Effusion

You're very welcome and I'm glad to help, or at least try to.
  
 All in all, it really depends on what you want to ultimately get out of the Elekit; this amplifier is so versatile when it comes to tube-rolling, the options are almost endless.  While trying a bunch of different types will give you the best overall depiction of the different sound signatures that can be had, this can be quite costly and quickly, so if you really don't mind shelling out the extra coin up front for some of the more expensive types, rather than going through all the bases first, than you might be best off with a vintage pair of KT88s, KT66s, and/or EL34s.  I've found that these are the ones that have given me the most enjoyable sound signature out of all the types I've tried, but they're not cheap.  That's not to say that the other, cheaper, variants are horrible or anything at all, as it really depends on the entirety of the system, for which every one is different.  I personally enjoy having quite a few different options and I'm consistently swapping them out depending on my mood and/or different genres of music I want to listen to.  It is also good to have a cheaper pair that you enjoy, so you don't have to log so many hours on your favorites.
  
 Is there anything that your setup seems to be lacking with your current pair of tubes?  Any preferences in the styles/genres of music you enjoy the most?  Both of these questions can help narrow down the massive amount of possible variants to try and with this particular amplifier that is probably an understatement.


----------



## JK-47

Just got back home from 3 weeks away at work. Time to roll some newly acquired tubes...
  
 First up the Blue labeled Philips 6189W's: I bought a sleeve of 5 for a reasonable price. All 5 tested strong and were closely matched as per the JAN 6189 requirements. Tested using reference 320kbps MP3's, and 24/96 vinyl rips that I'm very familiar with. Nice and neutral, tight, accurate, detailed, and refined. After 3-4 hours, they were very impressive, they are very transparent and don't add any color to the sound at all from what I can tell. I will definitely have to listen to these more... 
  
Up next the Green labeled Philips 5814A's: I also bought a sleeve of 5 for a little less than the Blue's. Very similar characteristics to their Blue Brother, with a touch more warmth. The bass and lower mids are slightly more pronounced at the cost of a tiny bit of detail. Another excellent value in my book...
  
I'll be putting in the Amperex 7316's a little later for a comparison. 
  
On another note I have a Schiit Gungnir Muliti bit DAC and Mojnir 2 amp (yay!!! more tubes to roll !!!), but the Wyrd arrived a day early. So I tried it with my TEAC UD-301 DAC, and I do have to say it made a difference. The background was blacker, and softer background sounds/voices/instruments were more detailed and easier to make out. Overall a small level of refinement was added to the sound. I would definitely consider adding this to any DAC for a small performance boost, and if you don't like it, return it within 15 days for almost all your money back.
  
 Also, my TEAC has been listed in the classifieds...
  
 Update: After listening to the Amperex 7316's... The 2 sets of Philips can't quite reach the same level's of detail and magic. The 7316's have a detailed majestic mid-range (I would call it sweet, and liquid), and extend to both ends of the frequency range effortlessly. If I had to rate the 7316, it would be a 9.5/10, the Philips Blue & Green would be a solid 8/10. The Philips are an excellent value at $9-$11 per tube. I will continue to listen to the Blue's for at least another 50-75hrs... I'll post an update in the near future.


----------



## JK-47

Yesterday my Schiit Gungnir Multi bit arrived, along with the Sennheiser HD650. This DAC is the real deal, extremely nice detail and smoothness. It pairs with the Elekit extremely well, and so do the HD650's 
	

	
	
		
		

		
			





.
  
 More impressions to come as the DAC continues to burn in.


----------



## Effusion

Thanks for the update JK and congrats on the new gear!
  
 I was able to try out a bunch of Schiit gear about a month ago and I was really impressed by the build quality to price ratio as well as the sound quality out of most of it.  Those 6189Ws and 5814A are very nice as well; let us know how they ultimately end up stacking up against your other types/variants.
  
 I'm glad you're enjoying the HD650s with the Elekit.  I've found that they pair up nicely to this amplifier and even better than much more expensive amplifiers.  Great combo to be had all around.
  
 I finally got around to modding my pair of HD650s and I can't tell you how much of an improvement it has made to the overall sound quality.  The mod I did, for the most part, can be found below and I highly recommend it:
  
http://apuresound.com/hdsennmod.html
  
 I did remove the foam discs from the back side of each driver as shown, however I cut a hole in the each of the foam inserts, then left them in each cup.  I simply used a quarter to cut the hole around and then put the foam inserts back in each cup.  To me, removing the foam insert completely changed too much of the sound signature of the 650's, which made them a bit too bright for my tastes.  The small quarter sized hole in the center of the inserts gives me just enough clarity and resolution, without loosing too much of the original charm of the 650s.
  
 To me this mod removes the small amount of "veil" that the 650s are known for, thereby improving the clarity, resolution, and voicing across the entire spectrum.  I highly recommend this mod and if you are careful, it is actually reversible.  I don't think I'll ever want to go back and I've been using a pair of unmodified 650s for about the last nine years or so.  Impressive!
  
 Keep us up to date on how things progress!


----------



## JK-47

The 6189W's have been in for 70hrs+ of play time, and they're a solid performing, reasonably priced option.
  
 Effusion,
  
 Thanks for the tips on the HD650's. I have a set of inner foam's on the way. I'm waiting for them before I try the qurater mod, I'm sensitive to treble. So I want an extra set on hand before I jump in. It might be a bit harder to replace the little foam piece's on the back. I'll try the quarter mod first and then see what happens.


----------



## Effusion

Thanks for the update, I actually have a pair somewhere and I remember them being a nice option for pretty cheap.  That is if the ones you are referring to are similar to those below:
  
http://www.dougstubes.com/jan-philips-6189w.html
  
 I recently auditioned a fully modded pair of HD650s, pretty much the same mod I ended up doing, and they really blew me away.  I've used the 650s almost exclusively for the past 6-7 years, so it was a welcomed change.  The pair I auditioned also had a thin layer of dense foam like material, I believe from a roll of carpet/rug mat.  The full mod does brighten them up a bit, which isn't much of an issue since my system definitely isn't bright.  The guy with the modded pair said the extra mat material helps smooth out the highs a bit more than without; I think I may be trying it soon, if just to see if I like the difference.
  
 I found that the foam on the back of the drivers can be a little hard to get out at first.  For some reason there was a bit of glue attaching the foam to the each of the outside studs, which caused difficulties for me when removing.  I don't really see any glue in the pictures of mod, which is noticeable a couple of places on mine, so I'm not really sure why my pair had it.  Not very much at all, but enough to really stick to the outside of the foam and causing it to tare a bit upon removal.  It would have worked perfect if I could steam the foam to loosen the glue, but I was never going to try it, as it was attached to the driver after all... oh well, in the end I was able to get it to break away and I've got to say they sound really good overall!
  
 Anyway, I really enjoy the 650's with this amp and find that it drives them as well, if not better at times, than many amps costing much more.  I find that the 650s have great scalability, so they can really help bring out the small nuances between gear/tubes/cables.  I would also have to say that this mod only increased it's ability to do so.
  
 Let me know how the new foam inserts turn out and if you have any questions regarding the mod or my time with the 650s and the Elekit.


----------



## JK-47

Effusion,
  
 Yes, those Philips tubes at Doug's are the same.
  
 I can't wait to get home and try the HD650 mods...
  
 Sorry for the long delay in replying, but I have been busy lately... I stopped in Tyll's of Innerfidelity on September 2nd, and checked out his "BIG Sound 2015" rooom full of All-Star gear. Wow !!! There's a video there (I was the first "victim"),and my own write up of the experience  should be posted by the end of the week. Then on the 3rd it was off to work, 3 flights to get there. Have been working 13-14hrs a day since...


----------



## Hyperslow

Just joined head-fi so I could let you know how much I appreciate all of the last years posts on this thread. I just finished building Victor's dx version of the 8200 and couldn't be happier. The pics I have seen of your amps just made me jealous too...so I indulged and powder coated the main chassis cover. 

I haven't finished burning in the stock 6l6GC tubes yet but my head is spinning with my options. They are just now starting to settle in after a hundred hours or so I'm going to have to jump in soon :wink_face:

Just a quick note about cans - I bought a pair of B&O H6 awhile back for portable use - I think they are 30ohm - and this amp drives them with ease. 

Anyway, just wanted to say thanks - I've subscribed to this thread so I'll post a bit more after I've had a bit more experience with this amp, maybe I'll post a pic when headfi gives me permission.


----------



## JK-47

Welcome to the discussion Hyperslow 
	

	
	
		
		

		
		
	


	




 
  
 Oh, Effusion,
  
 I did the HD650 mods at work and I'm enjoying them via a Geek Out V2 balanced output, awesome mods!!! Adds another level of clarity, very very nice. I can't wait to get home and try them with the Elekit !!!


----------



## lucidreamer

hyperslow said:


> Just joined head-fi so I could let you know how much I appreciate all of the last years posts on this thread.....


 
  
 Thanks Hyperslow and welcome to join the "Elekit TU-8200 DX Club"! Please share your modding and tube-rolling experiences with us and let us know if you have something to discuss with us.


----------



## Effusion

Welcome to the club and Head-Fi Hyperslow!
  
 I'm glad you're enjoying the Elekit and it sounds like your build went well.  Probably your best option initially is to get a good sense of the stock tubes and then let us all know what you think your system is missing.  I think you'll find that the tube options for this amp are quite extensive and I only hope we might be able to steer you in at least a starting direction.  I'd like to see your pictures of the powder coated chassis, that is once the site lets you.  I've recently bit the mod/upgrade bug myself; in the meantime, let us know how things continue to go and if you have any questions.  I agree, you made the right choice!
  
 JK-47,
  
 I'm glad to hear that the mod for the 650s went well and that your initial impressions are similar to mine.  I've spent quite a bit of time with the Elekit and a pair of un-modded 650s and to me, there is no going back, really that much better.  If they seem just a bit too hot or bright with certain combinations or tracks, the additional carpet mat foam mod may help tame the highs a bit.  I really don't find them too bright at all myself, but my system is warmer.  I may try this mod soon, as it is reversible, if just to see.  Let me know what you think of the Elekit through your newly modded pair!


----------



## JK-47

Effusion,
  
 It will be a couple of weeks till I get back home to let them loose on the Elekit, but they sound very nice as is. Not bright, more focused, revealing even more fine detail. My Dad just did the dampening mod, and will do the coin mod later. He likes to make small changes and listen for a few days at least, I tend to jump right in.
  
 I'll be going to RMAF this year, for the first time. I can squeeze it in before I go back to work


----------



## vkung

see you in the show


----------



## LingLing1337

See you all at RMAF! 

My Elekit is still working, it was just the kt88 that got destroyed. I definitely can't recommend PSVane anymore. Anyway I may pass the 8200 along to fund the purchase of an 8300, as I'm not using headphones (worthy of that level of amping) anymore.


----------



## vkung

You probably need to replace the FETs.  I can mail you the FET to repair your TU-8200.


----------



## LingLing1337

I'm actually thinking it could have been caused by handling with bare hands? At least thats what Grant Fidelity site says. Either way my Mullard el34 are still going strong.


----------



## JK-47

I don't think your bare hands would be the culprit...


----------



## LingLing1337

jk-47 said:


> I don't think your bare hands would be the culprit...




It seemed like a bit of an ass covering excuse given Grant Fidelitys posts you can find on other forums where they have to defend high failure rates for psvane tubes/capacitors.


----------



## Effusion

That does seem a bit weird, that is if they are stating that this will definitely cause the tubes to fail.
  
 I do remember reading a long time ago that oil from your hands can rub off onto the glass of the tube, creating "heat spots", where excess temperature has issues dissipating, but I've never used gloves with any of my tubes and don't believe it has ever caused issues.  I do not own any Psvane tubes though.
  
 Was it just the Psvane tubes that they said this causes issues with, or all tubes in general?  It would be very strange if they stated that this was only a problem with Psvane...
  
 I hope your luck improves and I'm glad the Mullards are holding up.


----------



## zw359

My TU-8200 kit is on the way.
	

	
	
		
		

		
			





 Thanks a lot for the great information here.
  
 I can’t comment anything about the “great sound” yet but I believe this kit was designed very carefully. How?  The detail assembly drawings/schematics are amazing. This effort in documentation convinces me that Elekit have very good design process, which normally will makes a good design.


----------



## Effusion

Very cool, congrats on the purchase!  I'm sure you won't be disappointed, it truly is a great amplifier and I agree, design is very important.  The sheer versatility and functionality of this amplifier is a testament to the great design of Elekit.
  
 Did you happen to purchase the DX version?
  
 I hope the build goes well and let us know how it progresses!


----------



## zw359

Thanks Effusion. I feel very sorry I didnt order from victor even after learned so much from here. Major reasons are low austrlian dollar and shipping cost. I once tried HD600 on a tube headphone amp and i coulndt tell the difference, so i set low budget for the first try. Luckily I found amazon in jp also offers this kit, not dx parts. Hopefully you guys will still help me if i have questions.


----------



## JK-47

zw359 said:


> Thanks Effusion. I feel very sorry I didnt order from victor even after learned so much from here. Major reasons are low austrlian dollar and shipping cost. I once tried HD600 on a tube headphone amp and i coulndt tell the difference, so i set low budget for the first try. Luckily I found amazon in jp also offers this kit, not dx parts. Hopefully you guys will still help me if i have questions.


 

 Congrats !!!
  
 If you have any questions that can't be answered here. Try Elekit directly, they respond quickly in english...


----------



## zw359

I didn't quite understand this L shape joint issue when I read this thread, till I got my hands on the kit last night.
  
 This is an *obvious *design defect to me. Solder is soft and kind of fluid under mechanical stress.
  
 I bent the cut off component leads into a small L shape and buried them under each solder bulb. Hopefully the flexible wire will take the mechanical stress. This took me lots of time and I haven't here the tube sound  yet.


----------



## JK-47

zw359 said:


> I didn't quite understand this L shape joint issue when I read this thread, till I got my hands on the kit last night.
> 
> This is an *obvious *design defect to me. Solder is soft and kind of fluid under mechanical stress.
> 
> I bent the cut off component leads into a small L shape and buried them under each solder bulb. Hopefully the flexible wire will take the mechanical stress. This took me lots of time and I haven't here the tube sound  yet.


 

 Mine hasn't failed...


----------



## zw359

jk-47 said:


> Mine hasn't failed...


 
 This kit is fairly new and the stress issue may not appear yet  or maybe it is a good design as the other aspects
	

	
	
		
		

		
		
	


	



  
 My standard for reliable industry equipment is too much for this DIY kit.
 I will keep working on it tonight


----------



## lucidreamer

zw359 said:


> I didn't quite understand this L shape joint issue when I read this thread, till I got my hands on the kit last night.
> 
> This is an *obvious *design defect to me. Solder is soft and kind of fluid under mechanical stress.
> 
> I bent the cut off component leads into a small L shape and buried them under each solder bulb. Hopefully the flexible wire will take the mechanical stress. This took me lots of time and I haven't here the tube sound  yet.


 
  
 I don't think this is a real design defect that we should worry about because there are several L-shaped solder joints instead of one plus an additional L-shaped metal corner piece attached to both PCB boards with screws for better mechanical rigidity. This is a common electronics PCB technique and I have seen it a lot before. It should be alright in the long run provided the two PCB boards were soldered at a right angle and did not encounter too much stress when installed to the amplifier rear panel. It is important to screw the metal L-shaped piece BEFORE soldering I think. Even a better idea to test the angle first by putting the board against the rear panel and adjust the angle if necessary before soldering. When I was putting mine together, I applied lots of solder to those connections to make sure that they will hold strong afterwards without losing connectivity. No problem so far.
  
 There is one possible heads-up moment in this amplifier is that the stack of wires going from the central power transformer to the AC UNIT board (if I remember correctly) can prevent the top cover from installing easily. When putting the top metal cover into place there is a chance that the wires can be crimped between and potentially shortened by the metal cover and the transformer if squeezed hard. Therefore when assembling it is a good idea to use a small wooden thin ruler or a stick and carefully pry the wires from being stuck in between those two metal parts. I learned it later after wondering why the top cover did not align easily with the screws like something prevented it from seating correctly. After figuring out that it was the wires - the problem was solved. Just my .02.


----------



## zw359

lucidreamer said:


> I don't think this is a real design defect that we should worry about because there are several L-shaped solder joints instead of one plus an additional L-shaped metal corner piece attached to both PCB boards with screws for better mechanical rigidity. This is a common electronics PCB technique and I have seen it a lot before. It should be alright in the long run provided the two PCB boards were soldered at a right angle and did not encounter too much stress when installed to the amplifier rear panel. It is important to screw the metal L-shaped piece BEFORE soldering I think. Even a better idea to test the angle first by putting the board against the rear panel and adjust the angle if necessary before soldering. When I was putting mine together, I applied lots of solder to those connections to make sure that they will hold strong afterwards without losing connectivity. No problem so far.
> 
> There is one possible heads-up moment in this amplifier is that the stack of wires going from the central power transformer to the AC UNIT board (if I remember correctly) can prevent the top cover from installing easily. When putting the top metal cover into place there is a chance that the wires can be crimped between and potentially shortened by the metal cover and the transformer if squeezed hard. Therefore when assembling it is a good idea to use a small wooden thin ruler or a stick and carefully pry the wires from being stuck in between those two metal parts. I learned it later after wondering why the top cover did not align easily with the screws like something prevented it from seating correctly. After figuring out that it was the wires - the problem was solved. Just my .02.


 

 Thanks for your suggestions.

 I finally finished the kit last night and it just works fine. I used 220uF aluminium polymer capacitors for bypassing and 0.1uF EPCOS film capacitor for decoupling because I have many of them lying around in my workplace. I connected FIIO X5 II line-out to the line input of TU-8200 in ultra linear mode.  I listened to some female vocals and the sound is very smooth from my HD600. I heard small buzz from the amplifier but it didn’t couple into the headphone.  I also tried small speakers from my ONKYO mini stereo CS-555. Even the 83dB/w/m speakers made loud sound by just spinning the volume by less than 30 degrees. I am not sure about the real output power but it’s certainly loud enough for my 4m x 5m room.   
 Unfortunately, I don’t have other good stereo systems other than my mini CS-555. I feel the mini system does a good job for my vocal favourites as well as the TU-8200. I will mostly use TU-8200 as my headphone amplifier.   I need to start saving for some good speakers in future, or maybe another DIY kit.


----------



## Canadian411

Sorry in advance but I didn't read all the 25 previous pages, my question is *Can I purchase built/assembled amp ? instead of soldering myself ?*
  
 Thanks,


----------



## JK-47

Contact Victor at vk music. He did offer prebuilt units, not sure if he still does.


----------



## LingLing1337

Ebay seller atop auction informed me the psvane kt88 I bought from him have a 1 year warranty, hopefully I will have a new pair soon


----------



## Jtyoung

anyone used the 8200 with iems? around 16 ohms - wondering how they pair...


----------



## vkung

it works well with low impedance caps


----------



## thebigcanman

Just received my amp. 
  
 After initial testing with GL KT88 and EH 12AU7 (both new/modern) i prefer the sound in ultralinear mode wiht my HD800. 
  
 What is the consensus on the best way to set this amp up? Triode w. some decent tubes?


----------



## Effusion

Congrats on the purchase!  Although I have not spent a lot of time with the TU-8200 and the HD800s, it sounds absolutely amazing with my HD650s, and I think you'll find that both the musicality and the sheer versatility of this amp put it up against units costing twice or more as much.
  
 I pretty much use the amp in Triode mode, which tends to give me a bit more bloom and fullness, but the Ultra Linear mode is also quite good, giving a bit more detail and speed.  If we took a poll, I believe it would be pretty close between the two, but to my knowledge, most are running Ultra-Linear with amazing results.  If you're planning on running speakers at all, Ultra-Linear will also give you a few more watts to play with.
  
 As far as tubes go, the possibilities with this amplifier are almost endless and there are very good options, both new stock and especially old stock.  In the new stock realm, Psvane are highly regarded, while other, cheaper versions, can sometimes seem a bit too solid state and laking the tonality/delivery achieved through their NOS counterparts.
  
 As far as NOS options, there are a ton of different paths, so it really has to do with what type of music you listen to most as well as what you're missing or wanting out of the marriage between the amp and your cans.  Many have enjoyed the airiness and mid-range magic of the old-stock EL-34s, while the 6550s and KT-88s give more punch/drive and slam.  A nice in-between I've found is the old stock KT-66s, that supply a great tonality with a natural presentation and great sound-stage, with a bit more weight than the EL-34s.  However, these versions, especially if they are NOS, are not cheap and can be hard to find.  A cheaper option, to get your feet wet with old stock, are the GE 6L6GCs or the SED Winged "C" EL34s and 6550s.  If you don't mind running adapters, I've really enjoyed many of the old stock 807s.  They tend to give me a well balanced sound, sort of in-between the KT-88, KT-66, and the 6L6GC, plus they can generally be had cheap; I tend to prefer the smoked glass militarized versions over the plain RCA.
  
 When considering 12au7s, there are so many that it is probably best to just try a few.  Many like the Amperex options, while I've found some of the Brimars and CBS black plates to be quite nice as well, with a bit more speed/detail than the Mullards, but still with a nice and lush sound.  The Telefunkens aren't cheap, but provide a ton of detail.  Some of the equivalents, including many of the militarized versions, may also provide a tighter sound with extra mid-range detail.
  
 There is a ton of information within this thread concerning different combinations and impressions, but please not hesitate to ask us questions.  I think you'll find that this amplifier is very receptive to tube rolling.
  
 Congrats again and welcome to the club!


----------



## JK-47

Good to hear from you again effusion, it's been a while


----------



## thebigcanman

effusion said:


> Congrats on the purchase!  Although I have not spent a lot of time with the TU-8200 and the HD800s, it sounds absolutely amazing with my HD650s, and I think you'll find that both the musicality and the sheer versatility of this amp put it up against units costing twice or more as much.
> 
> I pretty much use the amp in Triode mode, which tends to give me a bit more bloom and fullness, but the Ultra Linear mode is also quite good, giving a bit more detail and speed.  If we took a poll, I believe it would be pretty close between the two, but to my knowledge, most are running Ultra-Linear with amazing results.  If you're planning on running speakers at all, Ultra-Linear will also give you a few more watts to play with.
> 
> ...


 
  
 Thanks for the response! 
  
 I have no idea where to start with the tubes. I've been offered a pair of NOS mullards 12AU7s which I might check out. But I'm always weary of buying NOS tubes because it's too difficult to tell if they have been tested and in working condition etc. 
  
 At the moment with the KT-88 and EH 12AU7 the sound is just a touch veiled. Ideally I'd like to open the sound up a little bit. I DO like the KT88 tubes. I'm tempted to seek out some Winged Cs, but I'm getting bass and slam out of the HD800s in a way that I have never heard before.


----------



## Effusion

You're very welcome, I hope it helps!
  
 As far as the Mullard 12au7s, the vast majority I have tried all tend to be a bit laid-back in their presentation, but with a lush mid-range.  Therefore, you may not find them suiting to your tastes.  Many of the Amperex 12au7s are more forward and a bit brighter; plus there tends to be quite a few available.  There are differences between the orange globe (or red) and the Bugle Boys, but at this moment I can't really comment on them.  Others have also had good results with the Amperex.
  
 Another option is the Psvane 12au7 mark 2 I believe, which many have liked in the past.  They aren't cheap, but should hold up better than the KT-88s over time and still allow a bit of magic from a NOS power tube pair.  A cheap option, if just to get an idea, are the RCA clear top 12au7, which are forward and have nice impact, but lack a little detail, sound-stage, and bloom.  The CBS black plates, if you can find them, also provide a nice forward and engaging sound.
  
 Then there are the variants, for which there are a ton for the 12au7.  In general, the militarized versions tend to be a bit more detailed and forward, if not just a bit more solid-state sounding.
  
 As far as KT-88s go, NOS are VERY expensive and rare, but there are a few good new stock options out there.  I've enjoyed my McIntosh pair quite a bit, plus many have liked the Penta Labs versions.  Psvane also has a highly regarded KT-88 option, however a few have had their tubes die within a few months.  I've also tried a pair of blue JJ KT-88s that were nice, but a bit shallow.  The original "Gold Lion" KT-88s are probably the most expensive/rarest tube this amplifier can take and unfortunately, not many other NOS options exist.  You may find that you enjoy the 6550 type as much as the KT-88, but these two are rare and can be expensive; the RCA are very similar to the Tung-sol, but the Sylvanias and GE are different altogether.
  
 Glad to hear that the HD800 is fairing well with this amplifier.  I believe another owner, or two, use HD800s as well and have enjoyed the combo immensely.


----------



## Effusion

jk-47 said:


> Good to hear from you again effusion, it's been a while


 

 Hi JK, thanks!  It has been a while, I've been super busy lately.
  
 I have also finally finished the major overhaul of the TU-8200 case that I was telling you about back in October, so I'll try to get my notes together and share a few pics of the case soon.
  
 Hope all is well in the new year!


----------



## Greg70

thebigcanman said:


> Thanks for the response!
> 
> I have no idea where to start with the tubes. I've been offered a pair of NOS mullards 12AU7s which I might check out. But I'm always weary of buying NOS tubes because it's too difficult to tell if they have been tested and in working condition etc.
> 
> At the moment with the KT-88 and EH 12AU7 the sound is just a touch veiled. Ideally I'd like to open the sound up a little bit. I DO like the KT88 tubes. I'm tempted to seek out some Winged Cs, but I'm getting bass and slam out of the HD800s in a way that I have never heard before.


 

 If it's the high end you find veiled, NOS Tesla 12AU7s ares the best I've found.
 Very detailed like an Amperex but with a tad less mids and a bit brighter and very detailed top end.


----------



## Jtyoung

recently received my 8200 - nice to join the club!

 I opted for the Mundorf EVO Supreme silver gold coupling caps, and the AMRG components upgrade (popular upgrade in Japan I understand). All was organised (and built) by Victor - I received the amp ready to go with 4hrs on the clock. Those who know Victor Im sure will agree that he is extremely helpful in this somewhat small community of ours. Build is perfect and its a fine looking amp.

 My impressions are new - only after a few hours of my listening - Ill post more as i spend more glorious time with it. Im using it with custom iems, JH Roxannes, (perhaps a bit overkill) but this wonderful amp makes these iems really come to life - id say to their maximum potential! Im not a headphone guy, prefer the iem world - triple fi's, westone 4's, westone es5, roxannes. Nor have i tested with speakers yet. My source is Calyx-M and over the years ive gone through iphones, ibasso 50 and 90 and now the wonderful calyxm. Files are mostly 16/44.1 flac, some 24/96 flac and above, and some 320 mp3's (many genres).

 Ok - the sound. In a word - Stunning!! The best way i can describe it is akin to a headphone or source-device upgrade - it is simply amazing. Ive never experienced such a jump in sound with just a new amp! Many more details are revealed, fuller extension in both directions, improved layering, texture, imaging, realism, etc. Ive never heard a piano sound that good before...The details in the bass line of Daft Punks "Lose Yourself to Dance" really start to come through - closest to the way it shines when played through an AK240 player. Everything just sounds more "real", more beautiful.  I was a bit on the fence before i took the plunge but i need not have worried!  (This is my 2nd tube amp, the 1st being the elekit TU882).  Both are great amps, but the 8200 is just amazingly better - a lot more quiet through iems  - all in all, glorious. And all this with a fresh amp and fresh tubes. 
  
I opted for JJ 12au7's, and reissued mullard el34's, and also TAD 6l6gc's. So far i think i prefer the mullards, but a bit more bass would be nice. It may come through after more time - im enjoying the tube option experimentation thing. Considering kt-66's or maybe 88's but im keen to keep the tube sound also.


----------



## JK-47

Welcome @Jtyoung,
  
 Looking forward to your impressions with iems, I think you're the first to use them with the TU-8200 in this thread


----------



## thebigcanman

jtyoung said:


> recently received my 8200 - nice to join the club!
> 
> I opted for the Mundorf EVO Supreme silver gold coupling caps, and the AMRG components upgrade (popular upgrade in Japan I understand). All was organised (and built) by Victor - I received the amp ready to go with 4hrs on the clock. Those who know Victor Im sure will agree that he is extremely helpful in this somewhat small community of ours. Build is perfect and its a fine looking amp.
> 
> ...


 
 Are you running in triode? From what I can gather, running it in UL will typically result in an increase in bass (though probably at a cost somewhere else)
  
  
 What is a good price to pay for Amperex 12AU7?


----------



## Effusion

Greg70,
  
 By Tesla 12au7, do you happen to be referring to the Tesla ECC802S by chance?  I do have a pair of them, with gold pins, and I would definitely agree, they are very detailed, up-front, and nicely extended.  I have not heard the Tesla 12au7 however; I'll need to pick up a pair!  The Telefunken and Siemens ECC802S are very highly regarded, but come with a hefty price tag as well, so I have not tried them yet.  I also have a pair of Raytheon 7730s with gold pins that are probably the most accurate/detailed pair I've tried with great separation and air, however sometimes they can sound just a tad thin and maybe a bit tinny at times with certain passages as well.  I'll need to do a direct comparison between the Teslas and the Raytheons to get a better idea though.
  
 thebigcanman,
  
 I haven't kept up to much with the recent prices of the Amperex 12au7s, but I would say that a good price for a nice pair of Bugle Boys would be around $50-$70, while the orange globes are a bit rarer, so they can also go for more.  In recent years, prices have really skyrocketed, I believe my Bugle Boys and Globes were all less than $60 a few years back, so it can be harder, but good deals can still be found if you're patient.  Buying off the bay gives the largest selection and generally the best prices, but as you've stated, you never truly know what you are buying and having them tested before accepting or giving feedback is always good practice.  Unfortunately not all vendors outside the bay are that much more trustworthy, but exchanges can be easier, at least most of time.  Certain vendors will definitely take care of you and provide what they state, but unfortunately this usually comes at a premium.
  
 Generally the power tubes are a bit more important in terms of life and matching, however there is much debate regarding how much effect true matching has, whether it is more important to just have the triodes matched within each, while differences between the pairs can be within 5 to 10% and still be tolerable, or if both the triodes and pairs must be exactly matched or you get degraded sound.  I'm not sure if really anyone knows for sure, but it is best to look for matched pairs or match them yourself if you can.  Unfortunately many have had the cheaper new production power tubes burn out extremely quick as well, even less than 200 hours, while others have put thousands of hours on old stock; quality back in the day of tubes was generally much better than it is now unfortunately.  NOS is always the way to go if you can find them and can afford the extra amount, but even slightly used 12au7s can be worth it if you can get a good deal.  Even going with a reputable vendor for new production can usually be a big plus as they often offer their own burn-in (up to 72 hours or so) and matching after this; many factory direct pairs are often way off and not even closely matched as they state, information that came from not one, but two vendors I spoke with, plus some of the cheaper Chinese sometimes, but rarely, burn up in just a few hours due to defects, so it can really save you hassles in the end.  The world of tubes gets pretty crazy, and quickly.
  
 Jtyoung,
  
 Congrats on the purchase!  You're very right about Victor, truly a great guy and very helpful.  I'm glad to hear you are getting such great results with your JH Audio IEMs; this amplifier is awesome!  Many have also concluded that this amplifier is just as great with low impedance as it is with high.  I believe the spec of the headphone output is from 8 to 1000 ohms due to the design.  Pretty impressive range if you ask me, especially since many tube amplifiers are only good for higher ohm cans, which generally means more than 50, sometimes even 80 ohms.  This just adds the vast versatility of this kit.
  
 As far as the bass, it may be that it just hasn't burned-in enough yet.  I do remember that with less than 30 hours, the bass seemed soft and without much weight.  That all changed for me with about 30 hours of burn-in, also once I put a pair of GE 6L6GCs in as well.  At first I thought it was just the GEs, but going back to the stock EHs, I realized that it must have just needed some time to settle and luck had it that it happened right around my first power tube change.  Also try changing the output mode to see if it helps in the low-end.  It is a bit of a pain as you have to remove the case, but just let it sit unplugged for 10 minutes before doing so.  There are also some very clever case mods out there that allow easier switching, however you still need to wait a bit for the transformer, etc. to drain and you don't want anything that you could trip/switch while the unit is on.
  
 Let us know how things progress and welcome to the club!


----------



## Jtyoung

Thebigcanman,
  
 yeh im running UL mode currently
  
  
 Effusion,
  
 great thanks for the observation regarding burn-in - that was on my mind not to judge too early. and yes the ohm range is very impressive.


----------



## JK-47

thebigcanman said:


> Are you running in triode? From what I can gather, running it in UL will typically result in an increase in bass (though probably at a cost somewhere else)
> 
> 
> What is a good price to pay for Amperex 12AU7?


 
  
 I haven't followed Amperex prices too closely as of late either. I do have a pair of Orange globes ($45 for the pair) and 3 sets of the coveted 7316's which I paid between $70-$110 for the pairs (they can go upwards up $200 a pair). I really lucked out with the 7316's as two sets were mislabeled in the auction title (very few bidders), and the other set was labeled under a different company name. It took hours upon hours of searching, studying, looking at date codes and the physical qualities to determine I was indeed getting genuine quality Amperex 7316's.
  
 Hard work searching does pay off with great deals to be had, with both the power and pre tubes.
  
 My Elekit TU-8200DX is a workhorse with well over a 1000hrs of daily use, and no problems what so ever. I use it to watch tv and movies. Here is a pic of my set up.


----------



## Effusion

Nicely done on the Amperex 7316s JK!  You're right about doing your homework, being patient, and knowing what to look for.  Doing all of these things often allows you to at least break-even to the possibility of making a bit of a profit if you ever decide to part with them.  These things are a scarce resource and since many are so highly regarded in audio, the prices will probably just continue to climb in the future.  The nice thing about being patient and waiting for good deals on old stock is that if they test well their depreciation can be very low, especially compared to new stock whose value almost immediately diminishes after the initial sale and even without much use.
  
 I dig the setup!  The Elekit looks right at home.  I probably asked before or you may have told me already, but what single drivers are in those cabinets?  The look like the really nice Fostex FE Sigma series, but a bit hard to tell... how do they sound with the Elekit?  Eventually I might go this route in the future...
  
 Edit:  Should have first looked at your signature before asking 
	

	
	
		
		

		
			





... Fostex FE168EZ!  Very cool!  They look very nice...


----------



## Greg70

effusion said:


> Greg70,
> 
> By Tesla 12au7, do you happen to be referring to the Tesla ECC802S by chance?  I do have a pair of them, with gold pins, and I would definitely agree, they are very detailed, up-front, and nicely extended.


 
 Sorry yes.. I meant the ECC802S. I bought on your original recommendation and they're a very nice tube.


----------



## Effusion

No worries, with so many different variants I find it hard to keep them straight most of the time!  I'm glad you also enjoy them, I haven't had them in my unit in awhile, but I remember them doing just about everything right, whereas others often have at least a few shortcomings here and there.  I haven't had a chance to try out the Telefunken or Siemens versions yet, but the Teslas are so much cheaper it makes me wonder if they are really worth the extra price.  The Telefunken are very highly regarded though, so maybe a bit more detail and openness, but that's just an assumption.


----------



## Effusion

I did some comparisons last night between the Tesla ECC802S and the Raytheon Uniline 7730, along with my JAN smoked glass 807s as the power tubes.  Very close, but I think I actually prefer the 7730s, in my setup and with my custom Beyers.
  
 Both were really close and have excellent detail and extension, however the 7730 was more intimate and sweeter, whereas the Tesla ECC802S was a bit more sterile overall.  The bass seems to be better controlled on the ECC802S, but with a little less impact, and the sound-stage of the 7730 wasn't as nice and actually seemed a bit behind on certain tracks as far as depth; width between the two was both equal.
  
 Overall I think I prefer the more intimate and sweeter sound of the 7730.  At no time during my testing was it tinny or too bright at all, so I think it may have been the power tubes I was using before that lead me to that initial impression.  I would have to say that I highly recommend the Raytheon Uniline 7730, as it is an excellent sounding tube.  The only problem is that they are extremely rare, probably one of the rarest of all 12au7 variants, but if you can find a pair, definitely jump on them.
  
 As a side note, I'm not sure how many have tried the 807 power tube type yet, but I really like these smoked glass militarized RCAs.  My Siemens and Mullards are also quite nice as well.  For the price, even with the extra for the adapters, I think you'd be hard pressed to find much better, especially considering how much NOS EL34s and the KT series go for.  I believe I paid between $15 to $30 a pair for all my 807s.  Very nice and full sound with just the expense of a little detail and a bit of air/sound-stage.  Overall, the 807s are probably my favorite backup or when I just don't want to put more hours onto my more expensive pairs.


----------



## vkung

This upgrade OPT will give you more bass then the stock OPT (both are made by Atene - Japan) ​


----------



## Effusion

Very cool and interesting, thanks for the info and the picture!
  
 Do you happen to have any information or specification sheets for the upgraded LF OPT?  I can't seem to find much info on it.  Do you also know how much they run?
  
 Thanks again Victor!


----------



## vkung

THE upgrade OPT made by the same company (Atene Japan)  The size and weight are double.


----------



## Effusion

I'm interested in these upgraded OPTs, but still can't find much info on them nor the company.
  
 I'm assuming that they'll fit inside the chassis just fine and appear to be the same specifications, but do you know where one can purchase them?
  
 Thanks again!


----------



## vkung

This opt is custom made for TU-8200.  I am testing Lundahl LL1664/80mA too.


----------



## Effusion

Wow, the Lundahl LL1664/80mA looks really cool.  I for one would be very interested in what you are able to determine through your testing.
  
 Keep us all up to date on how it turns out and thanks for sharing!


----------



## vkung

The Lundahl 1664 is too big for TU-8200DX. I am working with Lundhal to have a smaller OPYT for TU-8200DX.


----------



## Effusion

That makes sense, from the pictures I was wondering if it was a little too big for the chassis.  I hope they are able to shrink it to a more manageable size in the near future, as I for one would be very interested in trying them out.
  
 I've recently switched from a traditional switching ATX power supply, to a Linear Power Supply to power my USB card, feeding my DAC, as well as my SSD, which holds all my tunes, and I've got to say that clean as well as noise free power (with almost zero ripple in this case) can give great results within the entire spectrum as well as lower the noise floor dramatically.  So, I'm definitely interested in any potential upgrades such as these to the Elekit in the future.
  
 Thanks again!


----------



## Effusion

I just finished pulling together my notes and getting the photos off my camera of the mods I recently did to the case of the Elekit, so I thought I'd share the process and results.
  
 A little background first.  Due to the case of Elekit getting quite warm, even a bit hot at times, especially with KT-88s and 6550s, I decided that I wanted to modify the case to allow some air flow through to the components and cool everything down in general.  I've also been wanting to paint the chassis for a while; whereas the silver was nice, it is a bit out of place for my uses.  After performing the air cooling mods, the case temperature went down to about a quarter of what it was originally stock, very nice!  However, using adapters/savers can also help reduce the surface temp as well, but I do like being able to use the straight sockets while not have to worry about the components underneath and closer to the surface.  It is more of a piece of mind than anything, as the without the mod, the case never got as hot as a few other amps I know about, so I don't believe this mod is ultimately required.
  
 I started by measuring and then cutting an 80 mm hole into both the top as well as bottom of the case to allow vertical air flow up and around the PCB, OPTs, etc.  I just used a dremel tool with metal cutters and then files to smooth out any burs.  I did not want to install actual fans for various reasons, but I just wanted a simple way to allow a little air from the bottom of the case to filter through and out the top.
  
 Once I finished drilling the holes for the mounts, I primed all the parts prior to painting.
  

  
 I ended up going with what is called "Carbon Mist" for the paint and I'm pretty happy with the end results.
  

  
 As far as the assembly of the top and bottom vents, below is a list of the materials used:

Two 80 mm stainless steel computer fan mounts with honeycomb grills - painted
Two 80 mm computer fan foam filters to stop/trap any large particles
Two 80 mm rubber fan mounts to reduce vibrations between the case and the assembly
The bottom ends of two 80 mm plastic fan enclosures to hold the foam
These were also covered in 3M RFI/EMI shielding, with cutouts for airflow; I figured since I was cutting such large holes in the steel case, it would be best to try to stop as many possible nasties from entering, or even exiting, at least as best as possible
https://www.digikey.com/product-detail/en/AB6005/3M6005D-ND/2213541


  

  
 Here is some pictures of the the enclosures before/after I cutout the vents with the shielding attached:
  


  
 I also decided to replace some of the screws, since they were getting a bit stripped and didn't mesh with the new color, with anodized black Hex screws and rubber washers to reduce any vibrations.  The vent assemblies are also easy enough to open to, allowing cleaning of the filter from time to time, so I'm not too worried about dust buildup.   Below are some pictures of the finished/assembled vents and filters:
  


  
 I also decided to replace the stock feet with these nice steel and rubber versions seen on the unit below:
  

  
 In all, I think it turned out pretty nice, except that I did go a bit heavy on the paint and clear coat, while forgetting that the front bezel is so tight!  Putting it back on, it chipped off a bit of the corner paint (seen left below), so I'll be doing some retouching/refinishing this spring/summer.
  


  
 I've tested the unit by running KT-88s for about three hours, without adapters, and where the case was getting the hottest before, right between the 12au7s as well as right behind the KT-88s, it was just warm to the touch, but no where near uncomfortable at all.  I can also feel a bit of warm air escaping from the top vent, so I'm convinced that actual fans are not necessary, just a good way for the air to flow through.  I'm thinking that the heat is about a quarter what it was before, so along with the new paint, I'm really happy with the results!


----------



## JK-47

Right on !!! great work !!


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## SuperDuke

My TU 8200 is on the way.  It's tempting to start looking at NOS tubes but I better make sure I can build a working unit first.
  
 More to follow in the coming weeks.


----------



## SuperDuke

PS  I wish Elekit still made their TU 8300R  300B Amp kit.  It got great reviews, had great tube rolling possibilities and would have been great w/ HE6s.


----------



## vkung

A new version of 300B amp  is in the planning stage... This new version will address the short fall of TU-8300R. In fact, TU-8300R is 6 years old old. It is time to  redesign this amp.


----------



## SuperDuke

That's  great to hear.   A headphone ouput would be nice.  Thanks for the update


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## vkung

Mr Fujita is working  on a very powerful pp amp. His next project is 300B amp. I will let him know  the possibility to add the headphone feature. Thank you for your suggestion.
 If you need help to build your TU-8200. I am happy to assist you


----------



## mhamel

vkung said:


> Mr Fujita is working  on a very powerful pp amp. His next project is 300B amp. I will let him know  the possibility to add the headphone feature. Thank you for your suggestion.
> If you need help to build your TU-8200. I am happy to assist you


 
  
 I'll add my vote for the headphone out. I was looking for a 300B headphone amp when I came across the TU-8200 and decided to go with that instead. I'd definitely be interested in building another amp if/when it becomes available.
  
   -Mike


----------



## vkung

The headphone feature  is a must for the next 300B amp.


----------



## Effusion

Congrats on the purchase SuperDuke!
  
 Let us know how the build goes and your first impressions.  I found that my unit needed about 30 hours of burn-in before it opened up, during this time the bass was a bit light and overall the sound was a little loose, but after around 30 hours it started to settle in.
  
 Once you've got a good feel for the sound of the stock tubes, let us know what you are lacking or looking more for and we can recommend some other options.  Many of the owners in this thread have had a ton of experience with both NOS and new production variants, so they are a great resource.
  
 Welcome to the club!


----------



## SuperDuke

vkung said:


> The headphone feature  is a must for the next 300B amp.


 
 I think it would be one of the few 300b amps w/ headphone output.  Transcendent Sound make a 300b OTL design but spec wise it seems to have a very low output that might not drive may of the flagship headphones.


effusion said:


> Congrats on the purchase SuperDuke!
> 
> Let us know how the build goes and your first impressions.  I found that my unit needed about 30 hours of burn-in before it opened up, during this time the bass was a bit light and overall the sound was a little loose, but after around 30 hours it started to settle in.
> 
> ...


 
 Thanks Effusion-  I really like your paint and ventilation work on your amp.


----------



## SuperDuke

Received the TU8200 yesterday and started confirming all parts.  A bit daunting at first but I think it'll be OK.  I'll reach out to the group here or to Victor If I run into problems.   I might need a fine tip for my soldering iron.
  
 I'm not going to make changes until I try everything in it's original form.  Just curious though-  has anyone tried different output transformers?  Would upgraded transformers make a significant difference?


----------



## SuperDuke

Have any of you that have built the TU8200 had problems w/ the instrucitons on page 3 (section 2 -list of resistors)?  My Hardcopy instructions that came w/ the kit and the online pdf both have little grey boxes (like autofil boxes or something) that give an incomplete description for some resistors -  For example "R (little grey box) 100Kohm"- where it should read something like "R2 100K".    No way to tell which number some of the resistors are.
  
 If you have directions that are clear please PM me Or am I missing something?
  
 thanks!
  
  
 EDIT- I just looked at page 8 which has the pictorial description of the the PCBs w/ resistor number and values-  that may work better than the page 3 instructions


----------



## JK-47

superduke said:


> Have any of you that have built the TU8200 had problems w/ the instrucitons on page 3 (section 2 -list of resistors)?  My Hardcopy instructions that came w/ the kit and the online pdf both have little grey boxes (like autofil boxes or something) that give an incomplete description for some resistors -  For example "R (little grey box) 100Kohm"- where it should read something like "R2 100K".    No way to tell which number some of the resistors are.
> 
> If you have directions that are clear please PM me Or am I missing something?
> 
> ...


 

 Don't hesitate to call, txt, or email Victor. He is quick to respond and very helpful.


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## vkung

i have just sent him a new manual.


----------



## SuperDuke

Thank you Victor for the quick response!  The new manual is fine.  I had started building from the figure on page 8 and it's very easy.
  
  
 A different question - several people are driving their headphones from the speaker taps on both solid state and tube amps.  Some are saying that connecting direct to a solid state speaker amp is fine but that the higher impedence of headphones may damage tube amps unless resistors are used at the speaker taps (eg. the hifiman adaptor).   I had planned to use my HE adaptor for the HE6 once I finish the TU8200.
  
 thoughts?


----------



## Effusion

Glad the build is starting to go better!
  
 As far as your question/inquiry into using the speaker taps to run your cans, I'm not sure if it would make much of a difference on this amplifier.  I admit that I have never done so, on this amplifier or any others, so my only reference is to my current understanding regarding the design of the 8200.  I believe that the headphone output/jack is virtually the same as the speakers and taps into the same part of the circuit.
  
 Victor would be able to clear up any confusion, but below is a portion of the 6moons review, by David Kan, on the Elekit TU-8200 that may help (http://www.6moons.com/audioreviews2/elekit/4.html):
  


> Being an apathetic headphone person and unqualified headfi reviewer, I thought I won’t write a single word on the headphone output to disguise my ignorance. But I heard too many good things about this particular feature of the TU-8200DX. It was with proper what-the-heck attitude that I plugged in my Sennheiser HD598 and cuffed my ears. I was literally stunned when Tchaikovsky’s _Romance Op.5_ muted on the speakers and came through the headphones. This old 1986/1988 but very touching recording of Tchaikovsky’s sentimental piece under Mikhail Pletnev [Melodiya SUCD-10-00048] seemed to be charged with even more emotions enkindled by the PAДИO 6n3c. The pianistic expression was adorned by warmth and an impassioned touch. Each note shimmered with a glowing accent and lingered on until it whispered its unwilling farewell. The musical rendezvous was simply poetic.
> 
> This pleasant surprise fermented curiosity. A quick check of the schematic (page 19, user manual) revealed that the headphone circuit branches out from the output tubes and output transformers. Three resistors (R39/40, R41/42, R43/44) on each channel readjust the output impedance to suit headphones from 8-1’000Ω. Being a headfi novice, I asked Victor if this was the typical topography for a headphone section found in integrated tube amps. He referred the question to Elekit and the answer came back within hours.
> 
> ...


 
  
 So, even though I can't really answer your question, I'm wondering if doing so would even make a difference and also that possibly putting a resistor/adapter between might even suck a bit of the life away.
  
 Hearing is believing though, so if you can get an answer and are confident it won't harm the amp nor your headphones, why not try.


----------



## SuperDuke

thanks for such a detailed reply.  it sounds like the headphone output on the 8200 may drive the HE6.  Only one way to find out and I'll report back given that my build goes well.  I am still putting resistors in and have many more to go.  Limited time w/ family and work and I am enjoying taking my time.


----------



## Effusion

Sure, not a problem, glad at least to try to help when I can.  I also see more of what you were talking about now; I'm not familiar with the HE6's, but a quick search shows that they are harder to drive than most.
  
 I'm sure Victor could get a more specific answer to the question, however I do know that the TU-8200 does have a lot of power as far as gain.  I use both the 300 ohm HD650 and the 80 ohm Beyer 770 Pro all the time and I never go much above 9 o'clock on the pot as it is just way too loud, for me.  Generally for these phones, and my listening preferences, slightly below 9 o'clock or even right at, for shorter periods, is plenty loud enough.  This is also true on pretty much all other headphones I've tried thus far and others at meets have commented on how powerful the amp is compared to ones they own or have owned.  However more than just gain goes into how well an amp drives a particular pair of cans and since I have yet to try the HE6's, I can't directly comment on the other factors.  The 8 to 1000 ohm range of the kit is impressive in my opinion and many have had great results with lower ohm models, including IEMs, as well.  I believe if power is the issue, switching it to UL or Pentode mode and using KT88s or 6550s, etc. should give you more headroom if desired.
  
 Do you happen to know if any other headphones compare to the drive required for the HE6s to sound their best?  There might be others here that have had some more experience with some of them, etc.  Then again I guess you'll know soon enough!


----------



## SuperDuke

THe K1000 might be closest to the HE6 in terms of difficulty to drive.  I had the K1000 for some time and find that the HE6 when driven properly is much more satisfying.  
  
 I am almost done w/ the first circuit board.  Been soldering a capacitor here and diode there.  This kit is crazy fun to build for a novice builder.  I would urge anyone apprehensive about building to give it a shot.  So far not hard at all.


----------



## SuperDuke

Finished the TU-8200 last night and it works flawlessly and seems to be dead quiet.  I need to let it "burn in" I think.  The dynamics are great and it has tons of power driving the Dharmas and HD600.  I was not overly impressed w/ the clarity.  I may be spoiled w/ the clarity of my solid state gear (Burson and Grace Design m920).
  
 I think Effusion said he heard some changes after 30hrs or so and I am using stock tubes.  I've also yet to try the Triode and Pentode modes. This kit was great fun to build!
  
  
  
  
  
 .


----------



## Effusion

Congrats on the completion of the build!
  
 Correct, it did take about 30 hours for my unit to tighten up a bit, for the bass to increase, and for the sound to open up.  I only used the stock EH 6L6GCs, briefly, and never used the stock 12au7s with the "China" marked in red.  I did not like the EHs very much at all, to me they had some great soundstage and air, however were less detailed, a bit veiled, and also a bit muddy and too laid-back as well.
  
 There are definitely better tubes out there than the stock and I don't believe any of the owners here still use the stock set.  It can be hard to tell at first where you'd want to start looking, but if you feel that there is something that would benefit your cans and/or your own ears, such as bright vs. warm, etc., it does help.  Let us all know what you might be looking for as many here have tried quite a few different variants and would be able to provide good solid advice.  Price ranges always help in giving recommendations as well, in addition to if you want to try NOS or stick to new production (in my experience NOS are the way to go, but are somewhat riskier due to dishonest sellers, however sometimes the quality/life of new production is troublesome).
  
 Glad the amp is showing its power and I agree it has a ton!  How does it fair with your HE6's?


----------



## SuperDuke

I switched my amp to Triode mode for first time and it really was like a different amp all together.  I think the UL mode had too much bass for me.  Interestingly the Dharma D1000s distort in triode mode at not too much volume.  The HD600 and HD800s do not distort that I could tell and sound wonderful. Maybe the impedance difference has something to do w/ that.
  
 So it seems I am looking for more mid magic, top end shimmer and tight bass.  My music is almost all Jazz (lots of trio) and acoustic. Tube Depot recommended I try the new production TungSol 6550. I am wondering if the EL34 would also be right for me.  I could go w/ NOS tubes but may try to find some friends w/ tubes I can try before plunking down lots of $


----------



## 430011

I am by no means an aggressive tube roller, but with HD650's I found EL34 tubes in UL mode to be really good. I didn't like KT88 in UL, but recently tried triode mode and found the KT88 to be excellent and the EL34 a little thin in the bass. You might find the EL34 a nice pairing. I've only tried the new production Electro Harmonix, NOS is beyond my budget.


----------



## mhamel

superduke said:


> I switched my amp to Triode mode for first time and it really was like a different amp all together.  I think the UL mode had too much bass for me.  Interestingly the Dharma D1000s distort in triode mode at not too much volume.  The HD600 and HD800s do not distort that I could tell and sound wonderful. Maybe the impedance difference has something to do w/ that.
> 
> So it seems I am looking for more mid magic, top end shimmer and tight bass.  My music is almost all Jazz (lots of trio) and acoustic. Tube Depot recommended I try the new production TungSol 6550. I am wondering if the EL34 would also be right for me.  I could go w/ NOS tubes but may try to find some friends w/ tubes I can try before plunking down lots of $


 
  
 I'd suggest giving the new production Gold Lion KT77s a try if you can, too. I'd also suggest going through Jim McShane for them as he has a great warranty.


----------



## Greg70

I think if your goal is mid magic, shimmer and tight bass.. I don't think find anything better than a pair of NOS Mullard EL34s. They're pricey but it's a rewarding investment.
 If you go that way look for the XF2 or XF3s. You will find them in other brands as well, but all made by Mullard and the codes will be etched onto the tube.
  
 From my experience the re-issue Mullards are not too far off and are a good way to see if this family of tubes is for you.
  
 Congratulations on the build.


----------



## SuperDuke

Thanks for all the tube suggestions!


----------



## tdogzthmn

I've been looking to get the TU8200DX to replace my Bottlehead Stereomour 2a3. I find that my speakers want more power than the 3.5 watts I get from the Stereomour. I'm also drawn to the flexibility of tube rolling and built in headphone amp with the Elekit.


----------



## 430011

I had a Stereomour too and loved it. Didn't have it concurrently with the TU-8200, so I can't make a comparison. I don't know if the power difference will be too noticeable, another couple decibels maybe. With the Stereoumour I had used Diy Sound Group horns, but it did run out of power with standard bookshelves. The TU-8200 does pretty well with my Carreras, but I'm in the process of building a DCPP for the extra power. 

I will say that the headphone out is an awesome feature and the wide choice of tubes is really nice. It's close to an end game headphone amp for me. As soon as KT-88 in triode gets old I can just switch back to EL-34 in ultra linear for something a little different.


----------



## thebigcanman

superduke said:


> I switched my amp to Triode mode for first time and it really was like a different amp all together.  I think the UL mode had too much bass for me.  Interestingly the Dharma D1000s distort in triode mode at not too much volume.  The HD600 and HD800s do not distort that I could tell and sound wonderful. Maybe the impedance difference has something to do w/ that.
> 
> So it seems I am looking for more mid magic, top end shimmer and tight bass.  My music is almost all Jazz (lots of trio) and acoustic. Tube Depot recommended I try the new production TungSol 6550. I am wondering if the EL34 would also be right for me.  I could go w/ NOS tubes but may try to find some friends w/ tubes I can try before plunking down lots of $


 
  
 I'm using the amp with HD800. Can I ask what set up you have? 
  
 I am using with Gold Lion KT-88 in UL mode...am tempted to pick up some EL34s and go for Triode


----------



## SuperDuke

I have been using the grace design M920 as DAC and mainly the HD800s or HD600.
  
 I think I have a rpoblem w/ my 8200 now-  I am getting distortion at reasonable listening levels happening w/ both the 6L6 stock tubes and EL34.


----------



## 430011

How do you like the 800 pairing with the 8200? I absolutely love my 650's and am putting aside a few dollars for an 800 or 800S. Haven't had a chance to actually try it out though.


----------



## SuperDuke

I'd love to comment but realize I am probably not hearing the 8200 as it should be.  I may have to write to Victor to see what may be causing the distortion I am hearing.
  
 If the distortion was not there I feel like the sound would be really quite good.


----------



## tdogzthmn

430011 said:


> I had a Stereomour too and loved it. Didn't have it concurrently with the TU-8200, so I can't make a comparison. I don't know if the power difference will be too noticeable, another couple decibels maybe. With the Stereoumour I had used Diy Sound Group horns, but it did run out of power with standard bookshelves. The TU-8200 does pretty well with my Carreras, but I'm in the process of building a DCPP for the extra power.
> 
> I will say that the headphone out is an awesome feature and the wide choice of tubes is really nice. It's close to an end game headphone amp for me. As soon as KT-88 in triode gets old I can just switch back to EL-34 in ultra linear for something a little different.




I love the bass from the 2a3 and would hope the tubes in the TU8200 can dig as deep. Id love a 300B amp but the price jump is more than I'd like to spend. 

I'm not much of a headphone listener these days so I'm mostly considering an amp for my Blumenstein Triton speakers which are rated at 92db.


----------



## Effusion

SuperDuke, any progress in determining what is causing the distortion you're hearing?  Do you happen to have tubes, other than stock, to try?  Sometimes a single tube can cause noise/distortion for various reasons.
  
 I hope you've been able get it back to working correctly, with Victor's help or on your own, but let us know if you need any help...


----------



## SuperDuke

Thanks for checking in.  Victor has been very generous in offering to talk on the phone - I've just been busy w/ family and work.  In the meantime I determined the distortion is in the R channel only and is there w/ stock 6L6s or new EL34s and also is present w/ different driver tubes, headphones and also w/ all modes - UL, Triode and Pentode.  So I think it is definitely the amp. I will try to get in touch w/ Victor next week. 
  
 Maybe it's a bad solder joint??


----------



## SuperDuke

My Tu8200 is fixed!  Big thanks to a fellow HeadFI member (Mourip) who helped me out.  I'm a bit ashamed to say but I forgot to solder one transisitor.  Well - this is a hobby after all and I have no background in electronics.  
  
 All is working perfectly, quiet no hum or anything and WOW this amp is very powerful!  Having the Grace Design as a DAC is nice b/c I can dial down the input depending on which headphones I am using.  The HD800S has bass that I feel in my body and the HD600 is amazing as well.
  
 The big surprise is the 8200 does not break a sweat driving the HE6 from the headphone jack.  I've not tried the speaker taps yet.    
  
 I have the Mullard re-issue EL34s that I got for $37 along w/ NOS Tungsram driver tubes - could not be happier.   In Triode mode the EL34 has very satisfying base for me.


----------



## Effusion

Glad to hear everything is well and that you're up and running once again!
  
 I also agree about the power of the unit... it is crazy!  My other two amps are pretty powerful as well and I really never go above 9 o'clock on them with any headphones; however, I do have a friend that likes to push speakers/headphones hard and likes his music very loud, so he has gone past 12 o'clock on all my other amps before.  For these stated reasons, I won't let him try the Elekit, just because I'm worried he'll blow or damage something by pushing the dial up too far...  he's one crazy guy!
  
 I'm glad that they also work well with the HE6s!  Seeing how difficult it is to drive those, I'm glad the Elekit will work for you for this purpose... with the ohm range from 8 to 1,000 on the unit as well as being able to correctly power the HE6, I'm wondering if there are really any mainstream headphones out there that it won't run!  If you ever get to trying the speaker outs on the HE6s, let us all know if you notice any difference in sound/signal.


----------



## 430011

Also glad you got things straightened out. There are not a few solder joints on that board. 

I like the idea of a DAC that you can dial back. I have to turn it down inside the player to even be able to get the volume to 9 o'clock. It's my one nitpick as a headphone only amp, but there is only so little power a KT88 can make. 

Also good to hear the 800S pairs well, I'm saving for that now, I think an 800S and a 650 will be all the headphone I'm interested in for a long time.


----------



## SuperDuke

Last PM I tried the 8200 as a speaker amp w/ my Spatial Audio Open baffle speakers.  They are 90 something db efficient so I expected the 8200 would have no trouble driving them.  What I did'nt expect was the level of dynamics and midrange presence and depth of stage I heard.  With the EL34s there was a sweet midrange that I've only heard in vintage gear but w/ dynamics and clarity I've never heard from these speakers.  With vocals and cello (Ben Solee -learning to Bend) it simply sounded like he was in my room.
  
 Hopefully my NOS RCA 6L6s will arrive this week.


----------



## SuperDuke

Update on the TU 8200 and HE6 - I was using the speaker taps to drive the HE6 via the HiFiman adaptor which is simply a box w/ resistors in it and XLR connection.
  
 I noticed the sound was good and there was plenty of headroom (more so than when driven from the phono jack) however I felt I'd lost some detail.   When I swithced back to the phono jack I heard better detail and still w/ lots of headroom.  Perhaps the resistors used in the 8200 phono out match better than the ones in the HIFiman adaptor.
  
 I think the HE6 is 83db (about 50Ohms) and even driven from the phono jack I don't get past 12 O'clock on the volume pot.
 I can't think of a less efficient headphone though the K1000 is 120Ohm and about the same efficiency (I don't have those anymore so can't compare).  It seems the 8200 could drive most any headphone well.


----------



## 430011

What do you guys think for pairing with the 8200: Music Direct has refurbished HD800 for $999 with a 2 year Sennheiser warranty. HD800S is at $1700. I plan on keeping the 650's for the smooth and darker sound. I don't like modding phones. I'm leaning toward original 800 for the price, but looking at my potential end game. I've heard the 800 briefly and really liked them.


----------



## SuperDuke

It's been awhiIe since I owned the HD800. I did compare it to the HD800S at a recent meet and preferred the 800S for what I thought was a more balanced sound w/ extended bass compared to the HD800.
  
 Might be worth your while to look at the Inner Fidelity review of the HD800 and HD800S on youtube.  Tyl preferred the HD800 with relatively simple mods but w/o mods liked the HD800S.


----------



## JK-47

430011 said:


> What do you guys think for pairing with the 8200: Music Direct has refurbished HD800 for $999 with a 2 year Sennheiser warranty. HD800S is at $1700. I plan on keeping the 650's for the smooth and darker sound. I don't like modding phones. I'm leaning toward original 800 for the price, but looking at my potential end game. I've heard the 800 briefly and really liked them.


 

 New HD800 for $1080 on Amazon right now. My HD800 arrived yesterday, and the TU-8200DX drives them very nicely. I plan to add the "Super Dupont" mod, which is on the way from France as we speak.


----------



## SuperDuke

Have my NOS RCA 6L6 tubes and they are nice.  A bit thin in triode mode though. Not dark at all w/ lots of detail and nice bass in UL mode.  I can say that for $37 on ebay and w/ the quality of sound I am getting from them the re-issue Mullard El34 is a hec of a good deal!  The HE6 just sounds excellent from the TU-8200.  They like lots of power and they are getting it from the phono jack.


----------



## mourip

Anyone tried modifying the TU-8200 yet? Looks ripe for simple cap and resistor upgrades.


----------



## JK-47

mourip said:


> Anyone tried modifying the TU-8200 yet? Looks ripe for simple cap and resistor upgrades.


 

 The TU-8200DX from Victor @VKmusic comes with upgraded resistors and caps already. Victor also offers a few other cap upgrades, and a few people in this thread (I know it's long) have tried other caps. Victor is also currently testing a few different transformers as well.
  
 @Victor, how is the transformer testing going? Are you going to offer them for sale yet?


----------



## 430011

I know I've seen photos of one with all the resistors replaced by AMTRANS AMRG. But at $4 a piece that is a mod I'm not prepared to undertake. It may be worth replacing just the resistors used in series for the headphone output. If I built another I may consider using Vishay RN55/60.
  
 There is a fair bit of room on the board for upgrading coupling caps. I used Audiocap Thetas. Mundorfs would be nice to try, but may be a tough fit. I have some Russian teflons too but they would require some creative thinking to fit. Some of the electrolytic caps can be replaced with nicer electrolytics.
  
 VK teased us with larger output transformers, but I haven't found any other information on them. I find this quite tempting.
  
 One of the guys a few pages back did some work to allow the amp to use 12BH7 tubes, but combined heater draw has to be considered.
  
 I would like to put a nicer pot in the amp. Due to the power of the amp I have to keep my volume pretty low, but left/right balance seems ok with the kit pot.
  
 But at the end of the day the amp in stock kit form is damn impressive. Rolling tubes may be enough modding for most people. While they may lack the cachet of NOS there are lots of new manufacture tubes to try out at fairly reasonable prices. With NOS you may be able to recoup some investment if you pass the tubes on.


----------



## 430011

jk-47 said:


> @Victor, how is the transformer testing going? Are you going to offer them for sale yet?


 
  
 Looks like I'm not the only one feeling the tease!


----------



## mhamel

430011 said:


> I know I've seen photos of one with all the resistors replaced by AMTRANS AMRG. But at $4 a piece that is a mod I'm not prepared to undertake. It may be worth replacing just the resistors used in series for the headphone output. If I built another I may consider using Vishay RN55/60.
> 
> There is a fair bit of room on the board for upgrading coupling caps. I used Audiocap Thetas. Mundorfs would be nice to try, but may be a tough fit. I have some Russian teflons too but they would require some creative thinking to fit. Some of the electrolytic caps can be replaced with nicer electrolytics.
> 
> ...


 
  
 I'm the person that did the mods for 12BH7, but I also put a better pot in when I built the amp.  If you look at the board where the pot mounts, it can be clipped out, lowered/connected with jumpers and an Alps blue pot dropped in. I'm pulling the amp apart now to take a few photos.


----------



## mhamel

Here you go - Alps Blue installed.


----------



## 430011

Wow that looks tidy! I think I have an Alps Blue or two floating around. Seems pretty straightforward. It might be time to break mine apart.


----------



## 430011

By the way, what do you think of the 12BH7? I imagine you could even try a 6SN7 with an adapter, I believe they also draw 600mA.


----------



## Effusion

SuperDuke,

 Thanks for letting us know about your experiences using speakers and I'm glad to hear the Elekit is pushing the HE6 well!  I think you've probably got the right idea about why the headphone out sounds better than through the speaker caps; either the resistors are different or the connections/connectors are losing some of the micro-detail, or even both to a degree.

 As far as speakers, I actually haven't tried mine much with the unit, for various reasons, but I'm glad to hear your positive experiences!  Others have also commented on how well the TU-8200 does with efficient speakers and in near-field setups as well.  The versatility of the amplifier is in my opinion, other than great sq, it's biggest attraction.  So, the fact that it can probably run pretty much every headphone thrown at it, plus at the same time be able to drive efficient speakers extremely well, is impressive to say the least.

 mhamel,

 I really like your modded unit with the Alps Blue!  Do you happen to know what the resistance of the model you used is?

 Evan99 and JK-47,

 I third the notion that I'm interested in the potential OPT upgrades Victor is looking into as well.  I think that if they can get the size down and the specs right there would probably be some interest here and elsewhere, as the OPTs are always areas for potential degradation and the quality of them is everything regarding potential distortion.  I also haven't found much info on the beefer units by Atene, but the Lundahl units look really nice!!


----------



## mhamel

effusion said:


> mhamel,
> 
> I really like your modded unit with the Alps Blue!  Do you happen to know what the resistance of the model you used is?


 
  
 Thanks!  Offhand, I don't recall, but it was the same resistance as the stock volume pot.


----------



## 430011

I took the plunge and ordered an HD800. The price difference was just too wide for me to make the leap to the 800S. And if I'm keeping the 650 I feel like I can switch if a particular album is coming off too bright. 

I've also been thinking of doing a little work under the hood. Probably will try some fancy resistors in the headphone section and I'm looking at pot upgrades. The break away section is nice for the blue velvet, but I may try a TKD if it would fit and just run fly leads. I need to do a little measuring.


----------



## SuperDuke

congrats on the HD800- I think you'll really enjoy them.


----------



## 430011

With about 6 hours of listening time now I have to say I think the TU-8200 and HD800 will be a long term pairing for me. It is just fantastic. I have to say I don't really understand some of the characterizations of the HD800 I've seen online. I've seen people say it's like a pencil to the eardrum or that 1/3 of their music is unlistenable. I haven't heard a single "unlistenable" song through this. Yes, if a song is poorly recorded or mastered it is very apparent but that is much different. The real proof is that my fiancé gave a thumbs up after listening to a playlist I made her. 

First aside: has anyone come across a compiled list of all the tubes that will roll in?

Second aside: over at diyaudio there is an Elekit sub forum and victor has posted a lot of good pictures, including more of the possible upgrade transformer. Still very intrigued by that.


----------



## clams

Quote:


mhamel said:


> Here you go - Alps Blue installed.


 
 What's the resistance of the pot? Was it a pretty easy install?


----------



## mhamel

clams said:


> Quote:
> What's the resistance of the pot? Was it a pretty easy install?


 
  
 Offhand, I don't remember - I used the same value as the stock pot.
  
 You have to clip out the section of the board that houses the pot... I did that, then sanded down the edges, made jumpers out of some of the heavier capacitor leads from the upgraded caps I installed. It already has pads sized for the Blue Velvet pot, so that part is simple. It's been a while since I installed it, but iirc, I mounted it to the small board, mounted the jumpers to that, fit it to get the correct height, adjusted the jumpers and soldered them to the main board.


----------



## Dimu

mhamel said:


> More updates from Elekit.
> 
> The limit is a combination of the output capacity of the transformer and the rectifier in the pre tube heater circuit. They suggested using a rectifier with approximately 2x capacity of the expected current draw for the heaters. I ordered a 1000v/2A rectifier to drop in but if that runs too hot I will go up to a 3A, which will require a bit more work to fit as the package size is completely different. As long as the rectifier is upgraded, it should be fine to run the 12BH7 with lower-draw power tubes to keep the total load on the 6v secondary < 4A.
> 
> ...


 
  
 Have you ever figured out a replacement transformer to drive more current to both the signal and power heaters at the same time?


----------



## SuperDuke

Got my hands on the ZMF Blackwood Headphone.  The TU8200 really wakes them up.  I'd say transformative is the right word.


----------



## thebigcanman

430011 said:


> With about 6 hours of listening time now I have to say I think the TU-8200 and HD800 will be a long term pairing for me. It is just fantastic. I have to say I don't really understand some of the characterizations of the HD800 I've seen online. I've seen people say it's like a pencil to the eardrum or that 1/3 of their music is unlistenable. I haven't heard a single "unlistenable" song through this. Yes, if a song is poorly recorded or mastered it is very apparent but that is much different. The real proof is that my fiancé gave a thumbs up after listening to a playlist I made her.
> 
> First aside: has anyone come across a compiled list of all the tubes that will roll in?
> 
> Second aside: over at diyaudio there is an Elekit sub forum and victor has posted a lot of good pictures, including more of the possible upgrade transformer. Still very intrigued by that.


 
 Evan99, I'm also using the 8200 with HD800. 
  
 I'm in ultra linear with KT88tube, but i want to move to triode with EL-34. What tubes/mode are you using with the 8200?


----------



## 430011

thebigcanman said:


> Evan99, I'm also using the 8200 with HD800.
> 
> I'm in ultra linear with KT88tube, but i want to move to triode with EL-34. What tubes/mode are you using with the 8200?




Right now I only have new production Mullard KT88 and Electro Harmonix EL34. I have found that I dislike the KT88 in ultra linear where the sound just didn't feel alive, but love them in triode. Then for EL34 I prefer to use the amp in ultra linear as I find the bass is a bit light in triode. They still sound nice, but swapping between KT88 and EL34 in triode will make the difference in bass apparent. I've never tried pentode. 

I've been cruising different tube sellers to see where I may experiment some. NOS is outside my budget/I'm wary of getting a defunct tube. I think I'd like to try the new production Gold Lion KT77.

Beyond that I'm very intrigued by the possibility of a set of larger output transformers for improved bass.


----------



## Dimu

430011 said:


> I've been cruising different tube sellers to see where I may experiment some. NOS is outside my budget/I'm wary of getting a defunct tube. I think I'd like to try the new production Gold Lion KT77.


 
  
 There are good NOS dealers who do extensive testing and who will accept returns should you be not satisfied. I would not worry about defunct tubes. Just buy at the right place and communicate your expectations clearly.
  
 As for budget it stretches from around $125 plus-minus $15 for matched pair of 6L6GC GE or Sylvania (both good tube choices) to north of $300 for short bottle RCA 6L6GC (sounds better than GE and Sylvania) to $400 and more for tall bottle RCA and European tubes like KT66. If you have never heard RCA or those European tubes you won't know that you are missing anything with either GE or Sylvania, and those are clearly better than modern tubes (especially if you subscribe to the concept that NOS tubes last longer than modern tubes, in which case GE or Sylvania price becomes very easy to justify).
  
 EL34 can be had reasonably priced too if you don't insist on original Mullards. For example RFT EL34 are fairly cheap in Europe- about half the price of Mullards. Genuine NOS KT88 are almost non existent unfortunately.
  
 Another way to improve sound with NOS tubes without major budget is to get NOS driver tubes- you will notice good difference relative to stock driver tubes. There are some good reasonably priced options out there and these tubes last a long time. Having said that I have to admit the more expensive driver tubes do sound even better (think Telefunken for example).
  
 You will always be able to "try new production". But trying those NOS tubes will be increasing difficult as time goes on.


----------



## SuperDuke

I have the Mullard Reissue EL 34s and could not be happier. Not sure what the XF2 designation is but I think someone on this thread steered me in that direction.  
  
 http://www.ebay.com/itm/290680925976?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


----------



## JK-47

Wow, tube prices have really sky rocketed in the last year. I was paying $60 a matched pair for GE 6L6GC's not long ago. Crazy !!!


----------



## Dimu

jk-47 said:


> Wow, tube prices have really sky rocketed in the last year. I was paying $60 a matched pair for GE 6L6GC's not long ago. Crazy !!!


 
  
 If you want unused tubes then yes, NOS power tubes are on their way to extinction and prices are going to continue to reflect that. 350B and KT88 are gone, GEC KT66 are almost gone, Mullard EL34 and RCA 6L6GC are going to be next to disappear, and eventually you'll see GE pairs for $500. 
  
 Also there are different GE vintages. Those from 1960s cost more than 1980s production. And I have an impression that GE tubes from 1960 sound better too.


----------



## tdogzthmn

Anyone have experience with this amp driving 600 headphones? I have an AKG K240DF and K400 (120ohm). Both are great headphones and I would hope the 8200 would serve them well.


----------



## JK-47

I have several tube testers, and have found even tubes advertised as NOS, are not. Just because the seller claims NOS, NEW, etc, doesn't mean they are, new crisp boxes do not guarantee a new tube. I've had "closely matched", "NOS", "unused", "not micrphonic" tubes from poplular sellers that were not as advertised when I tested them. The difference between the reputable dealers and the unscroupulous ones are, the good ones will refund /exchange with little fanfare. The bad ones will fight tooth and nail to avoid doing thre right thing.


----------



## JK-47

tdogzthmn said:


> Anyone have experience with this amp driving 600 headphones? I have an AKG K240DF and K400 (120ohm). Both are great headphones and I would hope the 8200 would serve them well.


 

 What are 600 headphones?


----------



## tdogzthmn

jk-47 said:


> What are 600 headphones?


 
  
 Meant to say 600 ohm headphones.  
  
 I'd like to know if the amp works well with higher impedance headphones.  I now see some posts mentioning good results with 300 ohm sennheisers so I would guess they can drive 600 ohm cans to high levels as well.


----------



## JK-47

tdogzthmn said:


> Meant to say 600 ohm headphones.
> 
> I'd like to know if the amp works well with higher impedance headphones.  I now see some posts mentioning good results with 300 ohm sennheisers so I would guess they can drive 600 ohm cans to high levels as well.


 
  
 Thanks for clarification, I wasn't sure if you were refering to the Sennheiser HD6x0 series or 600ohms. Works fantastic with the 300ohm Senns


----------



## Dimu

dimu said:


> Have you ever figured out a replacement transformer to drive more current to both the signal and power heaters at the same time?


 
  
 Would be interesting to hear whether replacement transformer worked out for Mike?
  
 I've got confirmation from Elekit that PCB conductors can handle double heater current for V1 and V2 tubes. So after upgrading the rectifier 600ma tubes can be used with 6L6GC and KT66, however using them with  EL34, KT88, 350B, or any other 1.5A+ tubes requires transformer upgrade. I think I am also going to add a fuse to the 6V transformer output.


----------



## mhamel

dimu said:


> Would be interesting to hear whether replacement transformer worked out for Mike?
> 
> I've got confirmation from Elekit that PCB conductors can handle double heater current for V1 and V2 tubes. So after upgrading the rectifier 600ma tubes can be used with 6L6GC and KT66, however using them with  EL34, KT88, 350B, or any other 1.5A+ tubes requires transformer upgrade. I think I am also going to add a fuse to the 6V transformer output.


 
  
 I did have a custom transformer made but it does not fit the existing space. It's on my project "to do" list to add an external case/umbilical for it.  I had reached out to several places, but didn't have much luck with responses. I ended up finding a guy over on diyaudio that custom made it for me.
  
 That's a good idea on the 6v output.


----------



## Dimu

mhamel said:


> I did have a custom transformer made but it does not fit the existing space. It's on my project "to do" list to add an external case/umbilical for it.  I had reached out to several places, but didn't have much luck with responses. I ended up finding a guy over on diyaudio that custom made it for me.




Thank you Mike. In that case it might be easier to just add external power 6v supply. Even if you use that transformer externally you only really need to run two wires to the amp. For me I feel it's not worth it if it does not fit inside- will have to live with the 4A limit. I think I will also measure all my tubes to know their actual heater draw.


----------



## Dimu

After soldering in 3A rectifier I tried Brimar 12BH7 with GE 6L6GC. Did not notice anything special relative to Brimar 12AU7 that I was listening to before with the same power tubes. Brimar 12AU7 replaced Telefunken smooth plate 12AU7- I liked Brimar sound over Telefunken. Waiting for Amperex gold pin E80CC to arrive (same heater power as 12BH7), maybe that rectifier will be useful after all.


----------



## thebigcanman

I will be swapping my amp from Ultralinear to Triode in the next few days, using GL KT-88 tube. Will report back on how it goes...hoping for a little more dynamism and soul in the sound


----------



## 430011

Bigcanman,
I'm very interested to hear your impressions. I felt like that change worked for me, but I don't want to bias your opinion. Lately I've been interested in snagging a set of GL KT-66. I suppose I should try the original 6L6 to see what I think first.


----------



## Dimu

430011 said:


> Bigcanman,
> I'm very interested to hear your impressions. I felt like that change worked for me, but I don't want to bias your opinion. Lately I've been interested in snagging a set of GL KT-66. I suppose I should try the original 6L6 to see what I think first.


 
  
 KT-66 is the best tube I heard in my TU-8200. But it is only true if you get a real GEC pair. If you are considering any KT66 other than GEC you will be better off getting a pair of GE or Sylvania 6L6GC- they costs a bit more than Russian KT66 but they are certainly worth the difference.


----------



## 430011

I've been playing around some this weekend with different tubes and modes. I'm using Tidal with a Schist Bifrost Uber and HD800.
  
 For me personally I've found new Mullard KT88 to be a little lifeless sounding in ultra linear, and I have to have the volume almost bottomed out and Tidal volume lowered to not blow my ear drums. Switching to Triode seems to add some nice life and sweetness to the sound, and I can turn the volume knob a few more degrees. The stock 6L6GC in triode seem nice and balanced, but doesn't really engage me. Electro Harmonix EL34 in triode are too bass light for me. In ultra linear they come alive and sound super sweet and engaging. But same as with the KT88 I have to lower the volume in Tidal and have the amp knob near the bottom. 
  
 Between EL34 in UL and KT88 in Triode I would have to say it is mostly a tie. I'll have to try switching back and forth a little more. 
  
 I think if there was anything I'd like to change about the TU-8200 is to have larger output transformers to pull just a little more bass and a more usable range of volume control for headphone use. I'm considering adding a series resistor to one of the inputs for headphone only use. That's the nature of having 4-8 watts of power available. I really need to put it back into my speaker set up for a good listening session.


----------



## Dimu

dimu said:


> After soldering in 3A rectifier I tried Brimar 12BH7 with GE 6L6GC. Did not notice anything special relative to Brimar 12AU7 that I was listening to before with the same power tubes.


 
  
 Tried 12BH7 again. This time I noticed better bass and I seem to like the sound more. So 12BH7 are staying in the amp for now.


----------



## Dimu

dimu said:


> KT-66 is the best tube I heard in my TU-8200. But it is only true if you get a real GEC pair. If you are considering any KT66 other than GEC you will be better off getting a pair of GE or Sylvania 6L6GC- they costs a bit more than Russian KT66 but they are certainly worth the difference.


 
  
 I was hoping to beat the amazing GEC KT66 sound and looked at 350B. Voltage specs seemed suspect and I shared them with Elekit. They came back saying screen grid voltage limit for 350B is not good enough and long term use in TU-8200 would be a safety concern. Basically they said not to use 350B with TU-8200. Too bad as tubedepot had them on sale at 60% off. My last hope to improve on KT66 is another GEC- I have some TT21 stashed away. Just waiting for adapters to arrive to give them a try in the amp.


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## vkung

The Lundahl LL 2764/80mA works well with TU-8200. I will ship the OPT to Mr. Fujita's  approval.


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## Dimu

dimu said:


> Tried 12BH7 again. This time I noticed better bass and I seem to like the sound more. So 12BH7 are staying in the amp for now.


 
  
 Got Dutch E80CC. Those tubes are beautiful looking and awesome sounding! Now struggling to figure out whether I prefer 12BH7 or E80CC. The one tube I have not tried yet is 6SN7, but I am not sure what the point would be as I already am confused by those two. Too bad I can't combine these preamp tubes with KT66 - that would be the ultimate combination.


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## Dimu

Here is how they look for comparison- Telefunken 12AU7, Brimar 12BH7 and Amperex E80CC.


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## Effusion

vkung said:


> The Lundahl LL 2764/80mA works well with TU-8200. I will ship the OPT to Mr. Fujita's  approval.


 
  
 Victor, those Lundahl LL 2764/80mA look nice and fit the chassis well!  I think I'm going to have to get a pair!  
	

	
	
		
		

		
			




  
 Dimu, thanks for all the information on those various alternate tubes; keep us up to date on all your findings.  It's crazy how versatile this thing really is!
  
 Also, I agree as well, the GEC KT66s are amazing and probably my number one choice as well.  I slightly preferred my smoked glass version and so did bixby awhile back, but to both of us, the original KT66s stood out.  To me, they do just about everything right and sort-of between a KT88 and an EL34, maybe with even a little splash of 6550s, but ultimately with its own sound.  All around a solid performer, but pricey due to scarcity.
  
 I'd also recommend trying out a nice pair of 807s, with adapters if you want a different flavor as well.  A few of the European variants, be careful as some have high plate voltages though, as well as some of the older smoked glass versions can sound very nice for the coin.  Even close to the best usually can be had for around $50 or less a pair; make sure you get adapters that have the right circumference, as they are all not the same.  Some of the European 807s have a slightly smaller top pin, while the RCA and American have a slightly larger one.  I actually use two sets of adapters though, one that is large enough for the US versions and one that is slightly smaller (actually the small one doesn't even fit the US ones).  Let me know if you're interested and I can send you the links to the ones I purchased, so you don't have to guess.  To me, they give a bit of the KT66 sound, with more of a 6L6GC flavor.  A little less soundstage and not the best at imaging, but they sound pretty good in my opinion and are my 'everyday' option due to price/performance.


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## vkung

I will send my pair  to Mr Fujita's approval .


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## Dimu

Thanks for the ideas! My next projects are to try GEC TT21 and Telefunken EL12 spez. Both require adapters and I am waiting for them to arrive from Asia. Same story regarding 6SN7- waiting for adapters. This week I have Amperex E80CC and RCA black plates in my amp.
  
 I've added TU-8500 preamp with Mullard 12AT7 and am planning to roll tubes in there however it is not as easy as TU-8200 as you have to disassemble it to swap tubes. Also due to the very heavy negative feedback TU-8500 is ridiculously transparent so I doubt changing tubes will make much difference in there. And because of dimensions, enclosed chassis and transformer limitations I can only use 12AU7 and 12AT7, no chance for larger tubes with bigger heaters. Also Elekit said not to use 12AX7 in TU-8500. I replaced negative feedback resistors in my TU-8500 so that it runs at around 2x gain instead of the default 3x (and switching it to 1x mode now brings it closer to unity, but I don't do it). Works well and gives broader volume adjustment range for TU-8200- both up and down. By the way I used TDK pots in both TU-8200 and TU-8500.
  
 I asked Elekit whether we can get a customized transformer wound with more than 4A rating on the 6V secondary or whether they could sell a second transformer to run it in parallel but neither request was met with much enthusiasm.


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## Dimu

First batch of adapters arrived, these are for TT21. Wow, the sound is more than I expected! But not with all recordings. It is kind of strange- some recordings sound much better with RCA black plates and E80CC and are kind of dull with TT21. But most sound so much better with this combination of Brimar 12AU7 and GEC TT21. It's like I need two amps to switch between them depending on the recording 
  
 Comparison with KT66 is next...


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## Dimu

Comparing GEC KT66 to GEC TT21 sound is similar, and similar deficiencies observed on the same recordings where TT21 did not sound good. I think the issue is that I am hearing the difference between 12AU7 and E80CC much more than the difference between RCA black plates, TT21 and KT66. Tried  three types of 12AU7- Brimars, Amperex-made Electronics for Medicine and Telefunkens. There are differences, but nothing like E80CC.
  
 Which means combining TT21, KT88 or KT66 with E80CC would be really awesome. It appears that this amp's power transformer is its biggest limitation... So for now E80CC and RCA black plates are back in the amp.


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## Dimu

> It appears that this amp's power transformer is its biggest limitation...


 
  
 I have ordered a custom R-core transformer with 50% higher current capacity on the 6V secondary. This should give me ability to run tubes like TT21 and drive them to full potential with preamp tubes like E80CC. This transformer will have bigger core and I will likely need to drill the bottom to move output transformers so that space opens up for this bigger power transformer. If timing works out I will swap out both power and output transformers at the same time, but that depends on when Lundahl are approved and available.


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## Dimu

More adapters arrived. Tried USSR 6H8C and Raytheon VT-231 manufactured for US Army/US Navy after Germany's surrender but prior to Japan's surrender. Both sound very good, definitely better than any 12AU7 I tried, but I still like E80CC the most. Those 6H8C are by far the best value though- in terms of the sound you get per dollar spent on tubes.


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## aedaza

Hi to all,
Just wantes to comment on my experience with some preamp tubes on this amp

New production Tung Sol 6189: nice tube. It is a good all over the spectrum kind of tube, with great detail, but some what lacks a bit of bottom. 

Sylvania 5814A 3mica gray plates: really nice and some of the most detailed highs. I should spend some more time with this one, but it is a nice balanced tube, but lacks a bit of omph on the low end.

Raytheon 3 mica black plates: this one is ok, but kind of a disapointment. You know, 3 mica and black plate? Expected a mid range with more meat, but it is a tube with nice highs but somewhat shy mids and lows. 

Rca 5963 blackplates: this one is a good suprice. It is energetic, great bass and mids. It lacks a bit of detail on the high end, but it could be a good complement to a system lacking a bit on the low deparment. It is a cheap tube, so worth the try! 

Rca cleartops 12au7a: love this one. It resolves the spectrum so nice. It has a very nice and open and high end and good botomless lows. It can be a bit bright sometimea, but this tube deserves some respect!

Cbs 5814a blackplates: my favorites... a midrange lifelike, lows that you can feel in the stomach and very nice highs.

I have been wanting to try the e80cc but dont know how the amp will handle them. Currently running some new prod goldlion kt88s. Nice too.


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## Dimu

effusion said:


> I'd also recommend trying out a nice pair of 807s, with adapters if you want a different flavor as well.


 
  
 Waiting for Cossor 807 round plates to arrive, as well as adapters for them. This is about the only tube other than 6L6GC that I can run with E80CC with the stock power transformer. EL12 spez might fit into the transformer power budget as well, but reliability of that calculation depends on the accuracy of rectifier efficiency estimate.


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## Dimu

aedaza said:


> I have been wanting to try the e80cc but dont know how the amp will handle them. Currently running some new prod goldlion kt88s. Nice too.


 
  
 Of all the tubes I tried (and I tried a lot of different tubes, all of them NOS, some of them costing north of $250 per pair) E80CC is the best driver for this amp that I found. Better than 6SN7, better than 12BH7, and definitely better than anything with small plates (i.e. ECC82, 12AU7, CV4003, etc). Notice, however, that you can't just plug them in- you've got to upgrade the rectifier first. This will allow you to run 12BH7, 6SN7, E80CC, as long as you use 6L6GC power tubes. You can't mix those large plate driver tubes with power tubes like EL34, KT66 or KT88 as it will overload the power transformer. Upgrading rectifier is cheap and simple, upgrading power transformer not so much.
  
 Regarding new production Russian tubes- I can't comment specifically as I would not buy any of those. I'll take any tube made in US or UK over anything made in Russia, new or old. The best factory in USSR was located in Moscow, and it is closed now. The second best was in Leningrad (you might know it as "winged C")- closed as well. So anything new you are buying is not even top quality by USSR/Russian standards. And those standards were never comparable to GEC or RCA or GE or many other quality US and Western European manufacturers.


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## Dimu

effusion said:


> I'd also recommend trying out a nice pair of 807s, with adapters if you want a different flavor as well.


 
  
 Just tried Cossor 807s. These might be my favorite 0.9A tubes! I think RCA black plates are going to get some rest while I am going to enjoy richer bass of Cossors. Thanks for the suggestion!
  
 P.S. these are not $50/pair tubes but still very good value for money compared to some more popular tubes like KT88 or KT66 or even RCA black plate.


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## Dimu

Comparing many good tubes is hard work 
 Today's challenge is Telefunkens made in Berlin. These bias very differently based on my tester's results but still the amp eats them up and produces beautiful sound!


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## Effusion

*Dimu,*
  
 Glad you're liking the 807s!  Those Cossors look really nice; they're the ones with the ceramic bases, correct?  I haven't had the pleasure of trying them yet.  I really like my smoked glasses, probably the best, then followed by a few military productions, including Sylvania, Westinghouse, and CBS, then the European variants, which some tie with the military US ones, then probably last the abundant standard RCAs, GEs, etc.  To me they are sort of between a KT88, a KT66, 6550, and even a bit of the 6L6GCs.  Nice full sound with plenty of weight.  I've seen the Cossors go for quite a bit, but the other brands are as cheap as NOS power tubes for the Elekit really get; I paid $25 or less for most pairs, however you have to factor in the adapters.
  
 Thanks for posting all your experiences with rolling the Elekit!  Very interesting and really amazing how many different types you've been able to use; crazy how versatile this amplifier truly is!  I'm going to have to try out a few in the near future, especially the 6SN7s, as I've always really enjoyed that type.
  
 If you ever get the time, it would be really cool if you were to ever put together a matrix of sort for all the different non-standard types you've successfully tried in the Elekit, plus some general info on what is required to run them.  I think it could really help out both current owners who are looking for different options and/or different flavors as well as those on the fence about going with an Elekit.
  
 Keep the impressions/findings coming! 





  
*aedaza,*
  
 Welcome to the club!  Thanks for sharing your impressions of some of the various tubes you've tried thus far.  I don't have much experience with the new production, but I agree about the CBS 5814a, they are one of my favs!  If you really like the CBS, I'd recommend trying a pair of Westinghouse 5814a's as well.  To me they are a bit sweeter than the CBS, being both more delicate and airier, with a bit better soundstage.  The CBS have more weight/punch though.  Let us know how things progress!
  
*JK,*
  
 I finally got around to trying out the Amperex 7316's and I've got to completely agree with you, they are amazing!  Very nice all around and probably my top pick as far as the balance between musicality and resolution/accuracy.  Whereas my 7730's are a bit too clinical at times and with certain power tubes, the 7316's bring the almost same benefits as they have, but with a more natural fluidity and balance.  Thanks for the suggestion!
  
 As a side note...
  
 I just had my unit upgraded with AMRG Carbon resistors and also replaced my 4 Amtrans AMCO film coupling caps with Mundorf EVO Supreme Silver/Gold ones.  I've got to say that this made a very noticeable difference, even prior to proper burn-in, and has improved everything from the detail to the soundstage/imaging.  It also sounds more natural now as well.  I highly recommend trying them if you are interested in upgrading; the Mundorf's aren't cheap, but worth it when you consider all the money one can spill out on tubes, etc.  If you're interested in these upgrades when ordering a unit, Victor offers them as part of his Supreme Upgrade.  Very nice indeed.


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## Dimu

effusion said:


> I just had my unit upgraded with AMRG Carbon resistors and also replaced my 4 Amtrans AMCO film coupling caps with Mundorf EVO Supreme Silver/Gold ones.  I've got to say that this made a very noticeable difference, even prior to proper burn-in, and has improved everything from the detail to the soundstage/imaging.  It also sounds more natural now as well.  I highly recommend trying them if you are interested in upgrading; the Mundorf's aren't cheap, but worth it when you consider all the money one can spill out on tubes, etc.  If you're interested in these upgrades when ordering a unit, Victor offers them as part of his Supreme Upgrade.  Very nice indeed.


 
  
 I had Mundorfs from the very beginning, in fact I used Mundorfs even for C19/C20 which was not easy to pull off due to limited space. My preamp also has Mundorfs that Victor offers. The amp has AMRG in all positions that Victor had them available for, the rest are AMRS. The preamp has four naked Vishays, bunch of AMRG, three native resistors and the balance are AMRS. The only way to improve on that is to use Vishays but that would double the price of the whole unit.
  
 I also used TDK pots in both the amp and preamp- Victor has those too. It fits into the amp as is, and for preamp I had to cut out the board as it is bigger than the stock Alps pot.
  
 I upgraded bypass capacitors to even higher ESR than what is offered in the DX kit, and I upgraded most of the other capacitors with high temperature automotive models.
  
 Basically most of the parts from my kit have never been soldered as I did extensive upgrades upfront.
  
 Another upgrade was using leaded silver solder from WBT. The amp worked from the first attempt and has been perfect ever since.


----------



## Dimu

effusion said:


> *Dimu,*
> 
> Glad you're liking the 807s!  Those Cossors look really nice; they're the ones with the ceramic bases, correct?  I haven't had the pleasure of trying them yet.  I really like my smoked glasses, probably the best, then followed by a few military productions, including Sylvania, Westinghouse, and CBS, then the European variants, which some tie with the military US ones, then probably last the abundant standard RCAs, GEs, etc.  To me they are sort of between a KT88, a KT66, 6550, and even a bit of the 6L6GCs.  Nice full sound with plenty of weight.  I've seen the Cossors go for quite a bit, but the other brands are as cheap as NOS power tubes for the Elekit really get; I paid $25 or less for most pairs, however you have to factor in the adapters.
> 
> ...


 
  
 I think I am close to the end of trying different tubes- not much left to try really. The one I still want to try are GEC ATS25 with round plates- those are similar to my Cossors 807. GECs come with ceramic bases, Cossors that I have are not ceramic- you can see the brown bases on the picture I posted earlier. The ones I still did not try were Tungsol 6550 (have not found NIB pair yet) and because of the high price I chickened out on experimenting with WE 350B due to their screen grid voltage specs. I suspect that 350B would actually be ok because it is rated as "design center values", but Elekit would not agree with this opinion despite repeated queries so I gave up on that.
  
 Regarding summary on what I tried and what I would recommend:
 1. make sure to triple current rating of the D7 rectifier. I would not run the amp without this upgrade as it would leave the amp limited to 12AU7 (and other related variants) for the driver tubes and even the best 12AU7s that I tried appeared to noticeably limit performance relative to tubes with bigger plates (and bigger plates require bigger cathodes which in turn require bigger heaters which results in more load on the rectifier and the power transformer).
  
 2. with this upgrade in place I prefer E80CC for driver tubes with other notable options being 12BH7 and 6SN7. I use Phillips E80CC made at their Harleen plant (these can be recognized by having a delta code etched on the glass) and I tried Brimar 12BH7. There are many 6SN7 choices to try but the best (like Soviet METZ version or TungSol round plate version) are close to impossible to find in good shape. Since use of these tubes limits available heater current from the power transformer for heating output tubes you can use 6L6GC and 807 tubes with these drivers. For 6L6GC I liked RCA black plates the most, and round plate Cossor 807s were very good too (this is what is in my amp now but those tubes are difficult to find in NIB condition). GE or Sylvania 6L6GC are good budget options here and are easy to find. Another interesting option is GE 7581A.​  
 3. The next level is upgrading the power transformer. This is a challenge and I have not done mine yet (even though I have the transformer with 50% more heater capacity waiting to be installed). This will allow to run tubes like:
 - GEC KT66- these tubes are awesome and are still possible to find unused.
 - GEC KT88/TT21. I did not find any NIB KT88 but I did manage to source TT21 which are at least as good if not better.
 - 6550- I tried Sylvania and GE versions, TungSol is supposed to be even better but it is as difficult to find as GEC KT88 these days.
 - EL34- Mullards made in England are considered best and those with lower XF codes cost more. RFT from East Germany are a cheaper option (these are branded as Siemens and many other brands).
 - EL12 spez- these are very cool tubes made by Telefunken in Berlin. There are other versions but I have only tried genuine Telefunkens.
  
 Of these tubes my favorites are KT66, TT21 and El12 spez, however I have not been able to listen to those long term due to transformer limitations so I am not sure which of these three I like best.
  
 Of the tubes that I mentioned the following require adapters (easily available on eBay):
 - 6SN7
 - TT21
 - el12 spez
 - 807/ATS25
  
 What I would not recommend:
  
 - I would not recommend running any of the tubes from the list under #3 above without power transformer upgrade because E80CC with good 6L6GC or 807 will produce more consistently enjoyable results than any output tube driven by any 12AU7.
 - I would not recommend buying any new production tubes- there are too many good NOS choices to enjoy while they are still available
 - I would not recommend buying used tubes not only because you don't know how much quality life is left in the tube but also because as cathode wears it produces a smaller electron cloud which gives the tube less of a buffer when it starts clipping. This means that new tubes will produce more pleasant clipping than old tubes (talking about used vs unused here, not about new manufacture vs NOS).
 - I would not recommend using anything that is underrated on either anode/plate volgate or second grid voltage. For example Soviet 6P3S and 6P3S-E are dirt cheap and have interesting sound, but I don't know how long they will last in this amp. 6P3S is rated to just 1000 hours and abusing it will likely result in quick deterioration.
 - I would not recommend trying to put bigger plate tubes into TU-8500 preamp- those should be either 12AU7 or 12AT7. I am currently running 12AT7 Mullards in there.
  
 Finally, I started listening in ultralinear mode and then I switched to triode mode, and I think I noticed some difference. However now I am planning to switch back to ultralinear next time I open the amp to give it more power which will reduce clipping.
  
 Overall this amp is amazing and is greatly recommended for both the fun of putting it together (especially if you start upgrading components) and for the continued enjoyment of the awesome sound that comes out of it.


----------



## Effusion

Thanks for all the info!  It really helps make sense of everything you've tried and what you had to do, and still do, in order to make it all happen.
  
 Wow, nice job on the upgrades!  I bet your unit sounds so much better than a stock one that you'd have trouble telling that they are the same amp without seeing them.  I may look into upgrading the pot at some point and it's nice to know that the TDK fits perfectly, while the Blue Alps mhamel I believe installed needed a little tweaking.
  
 I see what you mean about the Cossors, I guess I figured them to be ceramic sense the ATS25's are and the only pictures I've seen, they had white bases as well.  Very cool that yours have brown instead of white, I had not seen that before.  I have several ATS25's, one pair is even hand-painted and no other stamping since it is so old!  They are very good and their plate structure looks quite different to a normal 807.  I tried a very nice pair of NOS Mullard QV05-25, but these do not work with the amp as is and they blew my FET, so I do not recommend them unless you think you can tweak the amp to handle them.  Other than that, I have all 3 versions (different getters) of the newer militarized 807s, the 5933, and they are pretty good.  I've always felt that they were a bit more solid-state sounding than the general 807s and lack some of the tubey sound in general, maybe even a bit clinical in comparison, but they are worth a shot, if at least to see how they respond in your system.
  
 I do have a pair of Tung-sol 6550's and they do sound very nice.  I also have a pair of RCA's and GE's, both the coke bottle and the ones that look like larger 6L6GCs.  To me, the GE 6550s that look like larger 6L6GC's, with green lettering I believe, sound the best, then probably the Tung-sol and RCA's.  The GE coke bottle ones were my least favorite.  I also have not tried an original Genalex KT88, as they are impossible to find and if you do, they are way too expensive.  I have other KT88's though (Penta Labs, Mcintosh, etc.) and to me the 6550 shares many characteristics with it; they both have great speed and slam.  However, I think I generally prefer the more musical and open sound of the KT66, with my smoked glass GEC pair being my current fav.
  
 As far as EL34's, I've found some to be very nice, while others have fallen a bit flat.  I believe others have had better results with EL34's in UL mode rather than Triode.  Some of my favorites have been the Mullards, Siemens, Telefunkens, and Tesla's (both yellow label and "blue" glass).  One that really surprised me and is also one of my favs is the RCA Japan later production, which I got for cheap!  I have also tried the RFT's as well as the Winged "C" and they are both nice as well, giving some of the best soundstage, as also with the Tesla's.  Many of my pairs have had issues with the pins not being properly tapered off, so I use socket adapters for them as to not damage/ware the amp's sockets when I roll.  In general though, some of the other power types give me more impact and weight in the low end as well as speed/attack than the EL34's due in general, so I only really use them for when I'm listening to something that I want to have a more delicate/intimate feel to, such as classical music.
  
 I'll let you know if I have any questions before I try some 6SN7s, etc.  It may be a while though, as I only really have singles that I've used with other amps and would need to get pairs.  I've tried a ton of 6SN7s in the past and it is a very fun tube!  In my opinion the Tung-sol Round Plates weren't worth all the hype, as others gave me more of what I was looking for and at cheaper prices.  Same thing went for the "Bad Boys" as well as the RCA smoked glasses; both fell a little flat in my system compared to others.  I tend to prefer anything militarized, especially the brown bases and also "T" plates with square or "D" bottom getters, such as early Tung-sol and CBS.  The Brazilian aluminum RCA's also really kick the sound out as far as soundstage goes, the Brimars are quite good in the highs, the black glass National Unions have a ton of bass slam and extension, and my RCA smoked glass military brown base gives great sound from head to toe, if not for them being pretty rare.
  
 As far as 12au7s, I agree and tend to prefer the variants a bit more than the standards.  My favorite currently are Amperex 7316s, 5814a (both CBS and Westinghouse a bit more than the RCA's, etc.), my gold pin 7730's, CV4003's, Brimar 13D5's, and Tesla ECC802S.  I also tend to like most of the European types, except for a few Russian, ECC82's generally more than the standard 12au7s.
  
 It all just really shows how crazy tube rolling can get, especially with this amplifier!  With so many options you have to be careful not to drive yourself nuts!  I'm just glad others have also had such great experiences with this amplifier and its versatility.  For me, it is the amplifier I will hold onto for the rest of its days, enjoying every ounce of musical bliss it extends my way.  It also all reassures me that my review and constant recommendation of this amplifier is not only true to my own experiences, but to others as well.
  
 Happy listening and keep letting us all know where the journey is taking you!


----------



## Sonic Defender

Questions for those who have had some time with this unit. If I wanted to order a new one made for me, but didn't have a great deal of extra money beyond the basic stock configuration, what would you recommend as the most affordable, impactful upgrade I could ask of victor. I'm lucky to live moderately close to the distributor so no import fees anyway. I am looking at adding a tube amp to my collection, but frankly I won't get much into tube rolling as it is just a hyper complex area and I don't want to go down that rabbit hole. So I don't need the best tube amp and I was actually considering the Ember when this caught my attention. Any thoughts/comments? Thanks.


----------



## JK-47

Sorry to say, but you should probably stay away from tubes... Or go with GE 5814A input tubes @$20 a pair, and GE 6L6GC power tubes @$60 a pair, or play it safe and get modern tubes and know your amp will never live up to it's full potential. It's the truth...


----------



## vkung

I recommend to pick option #1 upgarde parts (upgrade the signal path to AMRS carbon resistor). If you have a  bigger budget later, you can replace the Amtrans AMCO to Mundorf EVO Supreme Silver gold.  and the driver tube (12AU7).


----------



## Sonic Defender

vkung said:


> I recommend to pick option #1 upgarde parts (upgrade the signal path to AMRS carbon resistor). If you have a  bigger budget later, you can replace the Amtrans AMCO to Mundorf EVO Supreme Silver gold.  and the driver tube (12AU7).


 
 Thank you for the suggestions, that sounds quite reasonable. Cheers.


----------



## Sonic Defender

jk-47 said:


> Sorry to say, but you should probably stay away from tubes... Or go with GE 5814A input tubes @$20 a pair, and GE 6L6GC power tubes @$60 a pair, or play it safe and get modern tubes and know your amp will never live up to it's full potential. It's the truth...


 
 Thanks for the thought, I hear where you are coming from. I would tube roll modestly, but it seems clear to me that it can become a crazy addiction rather quickly and lead to one never being content, just one more tube to try ... I know that is the thrill of the chase, but I would not want to get to deeply into rolling, not on principle, just from a practical stand point.


----------



## gasmonkey

Total tube newb question; these tubes are for sale close to where I live, are any compatible/recommended? 
 http://www.canuckaudiomart.com/details/649290694-assorted-amplifier-tubes/
  
 I dont mind grabbing it and keeping one or two to try and selling the rest.


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## Dimu

sonic defender said:


> Thanks for the thought, I hear where you are coming from. I would tube roll modestly, but it seems clear to me that it can become a crazy addiction rather quickly and lead to one never being content, just one more tube to try ... I know that is the thrill of the chase, but I would not want to get to deeply into rolling, not on principle, just from a practical stand point.


 
  
 You don't have to go crazy if you don't start chasing the best. I would recommend doing the following four steps:
 1. make sure you have upgraded rectifier for driver heaters. The stock rectifier can only power 12AU7 tubes and those are literally half the tubes that you can power with upgraded rectifier.
 2. E80CC drivers
 3. good NOS 6L6GC- if you can afford it go straight for RCA black plates, if not then grab a GE pair. Or if you have a bit of patience you can go for Cossor 807 with round plates and adapters for them (these tubes are awesome in UL mode). Do not look at any other power tubes than what I mentioned here as it will overload the power transformer with E80CC plugged in.
 4. And then stop. Improving it further is not trivial and expensive. Better invest into very good headphones and/or speakers and/or source.
  
 I have purchased from these sellers with no problems, here are examples of what you can grab on ebay right now:
 http://www.ebay.com/itm/2x-E80CC-6085-VALVO-PHILIPS-audio-tubes-NOS-E-80-CC-/281978489076
  
 http://www.ebay.com/itm/GE-6L6GC-USA-Tubes-NOS-NIB-OO-Getter-STRONG-103-103-MATCHED-PAIR-1970s-Nice-/371695022192
  
 http://www.ebay.com/itm/RCA-6L6GC-Tubes-NOS-NIB-Holy-Grail-BLACK-PLATE-Same-DK-Codes-1971-Mint-PAIR-/371644700151
  
 If you don't like ebay you can reach out to Brent at http://audiotubes.com he can set you up both with E80CC and 6L6GC tubes. Either way there are no duties for importing vacuum tubes to Canada.
  
 Insist on buying unused tubes- don't pay less for used ones, it is not worth it.


----------



## Dimu

gasmonkey said:


> Total tube newb question; these tubes are for sale close to where I live, are any compatible/recommended?
> http://www.canuckaudiomart.com/details/649290694-assorted-amplifier-tubes/
> 
> I dont mind grabbing it and keeping one or two to try and selling the rest.


 
  
 There are thousands upon thousands of tube types. Why would you buy some random assortment just because somebody said it is on sale? Just buy the tubes that you know where to plug them into.


----------



## Dimu

effusion said:


> Keep the impressions/findings coming!


 
  
 Since you asked for findings here are some from my today's test. I wanted to see how clipped signal looks on this amp. Test environment:
 - TU-8200 amp with Cossor 807 in UL mode driving 8Ohm LS50 speakers
 - TU-8500 preamp with Mullard 12AT7 equivalent tubes, buffer mode at 1.15x and amplification mode at 2.8x
 - both amp and preamp at max volume setting
 - Test signal around couple hundred Hz at 0.07V amplitude
  
 This is what happens with preamp in buffer mode (top trace is signal at 0.1V/div and bottom trace is speaker at 5V/div):

  
 Switching preamp to amplification mode produces this distortion:
  

  
 Here is another test at different frequency, buffer mode:
  

  
 And distortion when switching to amplification mode:
  

  
 So 0.07V signal at 1.15x gain does not get clipped at max volume but at 2.8x gain there is serious clipping going on. Signal from my DAC can peak out at over 2V amplitude (this track is good for driving my DAC past 2V at low frequencies: https://www.youtube.com/watch?v=yRHwWGO_A48) so it gets attenuated by the volume pot being set at pretty low setting. Good news is that for a desktop speaker even with low sensitivity like LS50 sound pressure gets to uncomfortable and unhealthy levels before clipping starts (beyond 90 dB according to my meter).
  
 My conclusion is that these tests confirm the reason why this amp sounds so good with both headphones and desktop speakers- no clipping even for near field listening.


----------



## Effusion

Nice tests!  Very cool, thanks for sharing them.
  
 This is good info to know... even though I'm currently only using the TU-8200 as a headphone amplifier, I plan on using it with my 91db at 1 watt efficient monitors in the future, that is as soon as my living situation changes.  Eventually I may go the single driver route and build some nice cabinets with the Fostex Sigma's or something similar.
  
 Let us know what else you find/discover/test and thanks again for sharing!


----------



## Dimu

effusion said:


> Nice tests!  Very cool, thanks for sharing them.
> 
> This is good info to know... even though I'm currently only using the TU-8200 as a headphone amplifier, I plan on using it with my 91db at 1 watt efficient monitors in the future, that is as soon as my living situation changes.  Eventually I may go the single driver route and build some nice cabinets with the Fostex Sigma's or something similar.
> 
> Let us know what else you find/discover/test and thanks again for sharing!


 

 Yes, this amp is really handy for desktop use- you get both headphone option and perfectly capable near field setup with desktop speakers.
  
 Will do more testing- planning to look at frequency spectrum and distortions of this amp but need to setup some lab equipment first. I know that swapping tubes changes sound but I want to see if this effect can be measured. Would be cool to have a more justified explanation of why those GECs and Cossors sound so different to modern tubes... Speaking of round plate Cossor 807s- I got myself some white ceramic base versions labeled as ATS-25 and VT60A but have not listened to them yet. My brown base Cossors have dual getters and the white ceramic base version has same kind of getter construction but only on one side. The brown base tubes are from December of 1955 and I think the ceramic base version is from 1940's. Interestingly the seller who sold me those white ceramic bases insisted that they were manufactured by GEC, not Cossor (tubes themselves do not have branding).
  
 And after I get this lab setup going I will then proceed to swapping out the power transformer. I don't want to do it until I have distortion profile established so that I can see if there is any negative effect from swapping out genuine Japanese transformer for a Chinese-wound one. And if that works then the next step would be to measure higher power tubes like TT21, EL34, EL12, KT66 and compare them to 807, RCA black plates, etc.


----------



## Dimu

Did a basic distortion test using HP 3561A analyzer. Don't have a good generator yet so using my Gungnir Multibit with a 24/192 sine signal wav file. Gungnir measured around -76.7 dB THD with no harmonics measurable by this analyzer- that's the baseline. Then set volume control to have 300 mV going into my LS50 speakers and proceeded to compare the amp.
  
 1. TU-8500 (Mullard 12AT7) with TU-8200 (E80CC with Cossor 807), measured THD at -55.4 dB. Second harmonic at -55.7 dBc and third at -68.4 dBc. So with no other harmonics visible second harmonic dominates which is supposed to be not too bad for human hearing perception.
  
 2. connected DAC signal directly to TU-8200, adjusted signal to 300 mV and tested again, this time it measured -63.6 dB THD with second harmonic at -65.3 dBc and third at -71.1 dBc. So TU-8500 adds some distortion and what's interesting is that second harmonic distortion from TU-8500 is much higher than from the third harmonic. I guess that's why I like listening via this preamp (and I measured that separately- my TU-8500 has large second harmonic distortion and no other measurable harmonics).
  
 3. swapped in Russian 6L6 that came with the amp. THD is at -67.2 dB. Second harmonic is at -69.8 dBc and third is at -73 dBc. So less distortion than Cossor tubes, and again the difference in 2nd harmonic is more significant than the difference in 3rd.
  
 A quick conclusion from these tests is that me liking this amp's sound is proportional to the magnitude of 2nd harmonic distortion.
  
 3. So to verify this hypothesis I swapped in RCA 6L6GC black plates, matched signal to 300 mV and got THD of -61.6 dB, second harmonic at -62.3 dBc and third harmonic at -72.6 dBc.
  
 4. This looks like a trend, so I stick in GE 6L6GC to confirm it. Again with matched 300 mV output I got THD of -61.3 dB, second harmonic at -62.1 dBc and third harmonic at -72.2 dBc.
  
 The difference between 2nd and 3rd harmonics is:
 Cossor 807: 5.8 dB
 Russian 6L6: 3.2 dB
 RCA black plate: 10.3 dB
 GE 6L6GC: 10.1 dB
  
 This means that with RCA and GE tubes over 90% of distortion is in second harmonic, and this difference goes much higher as power levels go up. I could not reconcile why Cossor is so far behind RCA and GE so I tested at 50% more power (600 mV) and Cossor caught up- it had spread between second and third of 12 dB,  Russian 6L6 had spread of 3.9 dB, RCA had spread of 13.7 dB, and GE had spread of 14.6 dB.
  
 I will need to run this test to higher power levels and preferably with more than one pair of newly manufactured tubes, however if this trend holds it shows that Russian tube is similar to NOS tubes on third harmonic distortion but NOS tubes add dramatically more second harmonic distortion, at least in my TU-8200 amp they do. Or maybe Russian tubes need more power to have second harmonic pick up (which would mean they suck for headphones) or I could simply have a freaky Russian tube (which would again speak to the overall quality of NOS tubes vs new manufacture tubes).
  
 Final thought- there were no measurable harmonics beyond 3rd with the amp. The combination of very strong 2nd harmonic and lack of measurable harmonics beyond 3rd explains why the amp sounds so good. I'll need to change instrumentation to actually measure where other harmonics are.


----------



## Dimu

Did more measurements today- checked 10 tubes in the amp, all with the same filament draw.
 As you can see from the included graph of 2nd harmonic Russian tubes plus one of my Cossor 807s aren't distorting enough and two of those have some shape to the line. The other 7 tubes are all hanging together and keeping things in a straight band. This was again measured with LS50 speaker as the load. Notice that 1V output is already loud, and at 4V output things get unhealthy for near field listening. So the interesting question to ponder is whether it is a coincidence that only 12.5% of NOS tubes tested are outside of that band while 100 of new manufacture tubes are out...
  
 Another interesting aspect is how tight and straight that band is for those 7 tubes considering they were all auto biased by the amp. That is one phenomenal amp!


----------



## sunneebear

Hello everyone, My name is sunnee and it's been 26 hrs since I rolled my last tube.
  
  
 I got my TU-8200DX at the start of August and for some reason I missed this whole thread.  I read Effusion's great review in research of this amp but some how missed the thread.  Well, just finished going through the whole thing and nice to meet everyone.
  
 For reference, I bought this amp to drive headphones.  My primary headphone is the MrSpeakers Ether C.  After that is the Sony CD3000.  I did not intend to use it as a speaker amp but after hearing what it can do I have cleaned out my whole system to only the Elekit.  My whole system now consists of a Questyle QP1R, the Elekit TU-8200DX, Ether C and a Jamo C607 3-way tower.


----------



## 430011

Welcome to the group Sunnee. 
 My 8200 is my primary headphone amp right now, using HD800. I also have a speedballed Crack and I plugged it in for a little bit the other day. After a few songs I just wanted to switch back to the Elekit. I don't get a lot of headphone time, so I feel like I need to maximize it. I think the biggest difference between the amps is how closed-in the Crack sounds, and not necessarily in a more "intimate" way, more of a constricted way. I'd really like to try an extended audition of Bottlehead's Mainline though. 
  
 I've been considering a pair of closed headphones too lately. The Ether C really catches my eye, also the new Fostex TH-610. But I've never tried a pair of Fostex cans, and unfortunately the Ether C is just too much for me to invest in.
  
 I feel like I must have exceptional self control in this group! I rolled in a pair of KT88 in triode mode and haven't changed in months! Although now I am looking at the PSVANE silver bottle KT88, anyone have any experiences with them?


----------



## sunneebear

430011 said:


> I feel like I must have exceptional self control in this group! I rolled in a pair of KT88 in triode mode and haven't changed in months! Although now I am looking at the _*PSVANE silver bottle KT88*_, anyone have any experiences with them?


 
  
 Hello Evan99,  I am using that very tube right now.  The Psvane KT88 T MkII is the silver bottle.  I am also using the Psvane 12AU7 T MkII.  They sound very clean, detail and spacious right off the bat but a needed warmer mids, and bass oomf.  That all changed after about 8 hours of running.  Now they are my favorite combo.  Everything seems perfect.  I don't think I will be rolling for a long time.
  
 These are the tubes I have tried.

 Top row:  Stock 6L6, Psvane KT88 T-MkII, Tungsol KT150.
 Bottom Row:  RCA clear top, Stock 12AU7, Psvane 12AU7 T-MkII, "NOS" Brimar 12AU7.


----------



## JK-47

Welcome fella's !!!
  
 Geez that KT 150 looks like a beast. You sure it's ok to run in the TU-8200?


----------



## vkung

Please don't try KT150, If you use KT150, it will damage the FETs.  .....too much current


----------



## sunneebear

I checked the specs and it's numbers match up with the KT88 so I thought it would be fine. Not having any problems but Victor says to watch the FETs.


----------



## JK-47

I'll take Victors word, he knows what he's talking about.


----------



## JK-47

sunneebear said:


> I checked the specs and it's numbers match up with the KT88 so I thought it would be fine. Not having any problems but Victor says to watch the FETs.


 

 The numbers don't really match up...


----------



## sunneebear

jk-47 said:


> I'll take Victors word, he knows what he's talking about.


 
 Agreed.  After the designers at Elekit, I don't think anyone knows more about this amp.


----------



## fccn75

Very interesting read for which I have not been around for a long time.  Call this whatever you like but as soon as I started catching the last few pages of this thread my left channel tube (EL34) died.  And nothing but loud hum coming from the left.
  
 As usual suspect per Vkung, yep, left channel FET is shorted and R18? or 17,  I forget (180 ohm carbon resistor) totally burned almost through PCB.  Was using in Ultra-linear mode all these years.  Tube definitely died.
  
 Curiosity question for Victor:  it appears the EL34 died taking out the FET & resistor overdrawing the designed current spec.  Would the same thing happen if Triode mode is used?


----------



## vkung

replace the FETs will solve the issue


----------



## sunneebear

Hello Victor,
 Any word on the upgrade output transformers?


----------



## fccn75

vkung said:


> replace the FETs will solve the issue


 
 Thanks Victor for confirmation.  Hope you don't mind me asking why did the 180 ohm resistor burned up?


----------



## vkung

too much current.. . this  will protect your OPT.
 If you need FET and 180 ohm to fix the issue, I have these repair parts.


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## fccn75

Nice to know, thanks, but was able to order from Mouser for both parts.  Harder thing to find are the EL34's, ugh...


----------



## vkung

Please consider.. Psvane KT88 MK II..


----------



## fccn75

Read all great things about the Psvane.  But I have a pair of Genelex KT88 but much prefer the EL34's.  Based on reading alone, the Psvane KT88 is on another level of performance.  Oh well...


----------



## vkung

It is good and reliable.. I like EH6L6GC too. Did you replace the driver tube? . I like Psavne MK II 12AU7.


----------



## 430011

Fccn75-
Have you tried your KT-88 in triode? In ultralinear I much preferred EL34 over KT-88, but when I had a free weekend to experiment I found I prefer triode KT-88 over ultralinear EL-34.


----------



## vkung

yes... I like the UL setting with KT88


----------



## fccn75

430011 said:


> Fccn75-
> Have you tried your KT-88 in triode? In ultralinear I much preferred EL34 over KT-88, but when I had a free weekend to experiment I found I prefer triode KT-88 over ultralinear EL-34.


 
 Unfortunately, I have not tried the KT-88 in triode mode, just UL all this time with all tubes.  I guess it's just the trouble of opening of the case for switching is a turn-off, and will not go into case mod (drilling holes) nor adding switches to accomplish swithing.
  
 Now that since I'm required to work on it due to the FET and resistor mishap, I will perhaps leave the top off temp so I can start trying out Triode mode for the KT-88.  BTW, very interesting read on UL and Triode operation - basically grids gets combined or a percentage of the combo along with triode not using global nfb.  All a bit over my head though...
  
 According to Mouser where I ordered the FETs, it should be close to mid next week.  We'll see how the repair goes and UL vs Triode for the Golden Lion.
  
 Thanks for the suggestion.


----------



## fccn75

vkung said:


> It is good and reliable.. I like EH6L6GC too. Did you replace the driver tube? . I like Psavne MK II 12AU7.


 
 So far I have tried the following drivers:  RCA clear tops, RCA black plates, Genelex, Westinghouse, JAN Phillips, Sylvannia, EH and nothing else exotic.  Overall for my preference, I enjoy the RCA black plates for vocals and Genelex for jazz.  
  
 I believe the stock power tube is the EH6L6GC? Since only playing the first week or so after kit completion, I started rolling in new tubes and have not looked back since putting in the Winged-C SED EL34's.  So I also have a few variations of 6L6's but did not enjoy them as much as the Winged-C.
  
 Looking forward to repairing and trying out UL vs Triode as suggested by Evan99.


----------



## vkung

You can try ...the EH 6L6Gc  with Brimar CV4003 / 12AU7 . It is pretty musical...


----------



## 430011

I'm interested to hear your impressions, see if I'm crazy or not. I haven't ever tried pentode now that I think about it. 

On another note, has anyone compared their TU-8200 to a Bottlehead Mainline or a Millet ECC99 SRPP? I'm getting a DIY urge.


----------



## fccn75

Finally got it repaired with the special FET from Mouser along with the 180 ohm resistor.  All in all, it's working now but using the KT88 now along with a pair of RCA black plates 12AU7.
  
 I tried the Triode mode as suggested but I did not like it as much as UL albeit affecting perhaps the bass notes which was very apparent to me.  However, I had a hard time distinguishing the differences between these two modes affecting mids and highs with my current KT88.  If anything, I still feel UL is ever so slightly forward sounding but the bass is very apparent being much more evident.
  
 I don't ever recall hearing a slight hum as related to power supply issues, but it started to be more apparent.  Not sure if the mishap affected the other components to have caused this.  Will be looking into the voltages at test points as per manual.
  
 By the way, anyone knows what value to change on the input side to decrease the gain of this amp?  Ever since kit completion, I've been only able to use at max 8 o'clock and even then it's a little louder than what I like.


----------



## fccn75

Just a few photos of the mishap and was able to clean it prior new parts.


----------



## 430011

So maybe I am crazy! Haha. Glad you got it working again, looks like it cleaned up well. I do agree that bass is more impactful in UL, particularly with the EL34. The KT88 seemed to lose less bass in triode for me. 

I've been noticing just a little hum lately when the room is totally silent. It's also funny you mention the gain, that's my number one complaint with the TU-8200 used exclusively as a headphone amp. I've considered replacing the PCB mounted RCA jacks with threaded ones and soldering a resistor in series with the input to allow more use of the volume pot.


----------



## fccn75

Nah, not crazy at all.  It's all purely subjective anyhow with just some of us prefer certain modes of operation.  I guess the consensus early on the thread suggested UL has more of a punchy sound.  I have been in that mode since the completion of my kit and only trying out Triode for a few occasions.
  
 Yeah, the hum never really been noticed before and recalled that it was eerily silent for a tube amp.  Now that I'm paying more attention to the repair, this 120hz hum is bugging me.  Although not loud but there enough to remind you of it's presence.
  
 I'll try different tubes first, but the only tubes changed out was the EL34 to KT88.  Perhaps I'll try the stock EH6L6 tonight and along with a Westinghouse 12AU7 just to eliminate tubes as the cause.
  
 What I fear is that the damaged caused by the original fault may have affected other components in the FET ripple filter.  I've only replaced the defective component - FET Q3 and R17.  Maybe I should have replaced Q5 as well but cannot figure Q5 will be affected...
  
 As for gain, wondering if Victor can suggest which resistor combination (hopefully with the approval of Elekit) of the 1st gain stage performed by the 12AU7 to modify without affecting too much of the impedance to lower the gain substantially to be more specific for headphone usage.  I don't ever plan on using the 8200 for speaker at all since the pair of Rogers is just too inefficient for this amp and for that I have the Silver 7T.
  
 It will be ideal for me to be able to use the volume at around 10:00 to 12:00 instead of just 7:00-8:00!


----------



## 430011

Viktor,
If Mr. Fujita ever decided to design a low power kit exclusively for headphone use featuring higher end output transformers I would be willing to sign up for the initial production run...


----------



## fccn75

Vkung, will you please check with Mr. Fujita what lower values of plate resistors in the 12AU7 stage is recommended primarily for headphone (will not use speakers ever) usage without detrimental effect on output impedance driving the power stage, thanks in advance.


----------



## Dimu

fccn75 said:


> By the way, anyone knows what value to change on the input side to decrease the gain of this amp?  Ever since kit completion, I've been only able to use at max 8 o'clock and even then it's a little louder than what I like.


 
  
 There are two things that you can change to reduce output volume- attenuate incoming signal or increase negative feedback. The difference is that increasing negative feedback decreases distortions while attenuating signal does not. I kind of like my distortions because unless you drive the amp too hard 2nd harmonic is pretty much all you get in terms of distortion. This means your amp makes your music more musical 
  
 If you do want to change actual gain this amp has global feedback so you can play with that.
  
 In terms of attenuating there are two ways to do that- passive or active. TU-8500 would be an example of an excellent active option. Not only it looks good stacked with TU-8200 and gives you a second pot that allows you to adjust volume easily but it also has a mode close to 1x which makes that pot useful at its full range (i.e. just leave your amp pot a fixed low setting and use preamp pot to regulate volume). You could take it further by driving TU-8500 below 1x gain by decreasing value of negative feedback resistors. I did that to my TU-8500 but my mod dropped it very close to unity but still above 1x.
  
 If you want to go passive you could look at changing your pot or adding another passive attenuator in front of it.


----------



## Dimu

fccn75 said:


> Vkung, will you please check with Mr. Fujita what lower values of plate resistors in the 12AU7 stage is recommended primarily for headphone (will not use speakers ever) usage without detrimental effect on output impedance driving the power stage, thanks in advance.


 
  
 You don't want to alter the driver circuitry- it is not what controls gain of this amp. Try to lower R35 and R36 to bring gain down if you really want to experiment with gain.
  
 But likely the simplest solution is simply adding inline RCA attenuators to your amp inputs. This would become part of input voltage divider together with your pot which will allow you to use wider range of motion.


----------



## Dimu

fccn75 said:


> BTW, very interesting read on UL and Triode operation - basically grids gets combined or a percentage of the combo along with triode not using global nfb.  All a bit over my head though...


 
  
 The best read on UL is the original patent: https://patentimages.storage.googleapis.com/pdfs/US2710312.pdf


----------



## 430011

dimu said:


> But likely the simplest solution is simply adding inline RCA attenuators to your amp inputs. This would become part of input voltage divider together with your pot which will allow you to use wider range of motion.




My idea for this was to connect one of the input jacks to the amp circuit with a pair of fancy resistors in series, and leave the second input as is. Then run a Y cable from my DAC to both inputs. Select whichever input is appropriate for headphones or speakers. I don't have it hooked up to speakers at the moment so that is really moot...

My ultimate dream would be a roughly $1000 headphone only amp from elekit though. Seeing the price points of the TU8200 and upcoming TU8340 I feel like that could be long term stopping point for me.I have to keep in mind that elekit is not primarily an amp company.


----------



## fccn75

dimu said:


> There are two things that you can change to reduce output volume- attenuate incoming signal or increase negative feedback. The difference is that increasing negative feedback decreases distortions while attenuating signal does not. I kind of like my distortions because unless you drive the amp too hard 2nd harmonic is pretty much all you get in terms of distortion. This means your amp makes your music more musical
> 
> If you do want to change actual gain this amp has global feedback so you can play with that.
> 
> ...


 
  
 Thanks for the suggestions.  And very interesting read of UL, btw, is that the same David Hafler of HAFLER amplifiers made famous by using MOSFET outputs vs bipolars?  Bring back fond memories!
  
 Definitely don't want to mess with the NFB since presumably Elekit has that parameter specifically dialed in for its fantastic SQ.  I was hoping to have a quick mod since the amp was already opened for the repair I made with FET/resistor.
  
 Was thinking of R27 due to it being the plate resistor for which typical common cathode designs directly control gain prior the power stage(s). Figuring only 1 resistor to change or even placed in in parallel with another for gain reduction.  But was worried about the detrimental affect on the Z matching of the power stage therefore affecting its parameter(s).
  
 Anyhow, passive before the input is perhaps a better route as you have noted using resistor padding it down before the pot.  Along similar idea as using the TU-8500 prior 8200, adding another pot prior to the input is another option perhaps using a 1M ohm driving the internal 100K.
  
 Evan99, the y connection mentioned I believe would work out well since inputs are switched therefore not affecting each other while the Z out of most DACs are very low (100 ohms or less?) still qualifying the 1:10 rule.
  
 Time to try out a few values of pot before the input...


----------



## Dimu

fccn75 said:


> Thanks for the suggestions.  And very interesting read of UL, btw, is that the same David Hafler of HAFLER amplifiers made famous by using MOSFET outputs vs bipolars?  Bring back fond memories!
> 
> Definitely don't want to mess with the NFB since presumably Elekit has that parameter specifically dialed in for its fantastic SQ.  I was hoping to have a quick mod since the amp was already opened for the repair I made with FET/resistor.
> 
> ...


 

 It is ok to mess with NFB. In fact Elekit's own TU-8500 even has a button for messing with NFB- it adds a parallel resistor to the main NFB resistor to reduce gain. You just have to mess with the most global NFB in the amp. There are multiple NFB circuits in there. The global NFB is at the top where it says "NFB" near R35/R37 and R36/R38. That feeds output from the transformers into the cathode of the first triode stage, which makes this "global feedback" as it envelopes the whole amp. If you change any of the local NFB parameters it will simply be compensated by the change in global NFB so that gain remains the same.


----------



## Dimu

430011 said:


> My idea for this was to connect one of the input jacks to the amp circuit with a pair of fancy resistors in series, and leave the second input as is. Then run a Y cable from my DAC to both inputs. Select whichever input is appropriate for headphones or speakers. I don't have it hooked up to speakers at the moment so that is really moot...


 
  
 That would work well as you would essentially create a passive switchable attenuator. I was just saying that instead of "resistors" you can stick in RCA attenuators. You could combine that with your Y cable idea to get switchable attenuation without changing anything in the amp.
  


430011 said:


> My ultimate dream would be a roughly $1000 headphone only amp from elekit though. Seeing the price points of the TU8200 and upcoming TU8340 I feel like that could be long term stopping point for me.I have to keep in mind that elekit is not primarily an amp company.


 
  
 I am happy with the amp other than power transformer limitation on the heater current and space limitation that prevents use of bigger output transformers. Other than that it really is outstanding.


----------



## Dimu

fccn75 said:


> Definitely don't want to mess with the NFB since presumably Elekit has that parameter specifically dialed in for its fantastic SQ.


 
  
 One more comment on this- if you don't want to play with the frequency response of NFB then you can simply increase the value of R3 and R4. Doubling those resistors should noticeably decrease gain of the whole amplifier.


----------



## fccn75

dimu said:


> It is ok to mess with NFB. In fact Elekit's own TU-8500 even has a button for messing with NFB- it adds a parallel resistor to the main NFB resistor to reduce gain. You just have to mess with the most global NFB in the amp. There are multiple NFB circuits in there. The global NFB is at the top where it says "NFB" near R35/R37 and R36/R38. That feeds output from the transformers into the cathode of the first triode stage, which makes this "global feedback" as it envelopes the whole amp. If you change any of the local NFB parameters it will simply be compensated by the change in global NFB so that gain remains the same.


 
  


dimu said:


> One more comment on this- if you don't want to play with the frequency response of NFB then you can simply increase the value of R3 and R4. Doubling those resistors should noticeably decrease gain of the whole amplifier.


 
  
 Points well taken, Dimu.
  
 However, specific values must be calculated along with so many frequency compensations to deal with affecting FR and even IMD, I sure like to run this by Mr. Fujita to see what his preference would be for overall gain reduction. And to that extent the recommended dB of attenuation.


----------



## ForSure

On my 8200DX, the right channel some time have this distortion.  I wonder is it because of the tube going bad?


----------



## 430011

forsure said:


> On my 8200DX, the right channel some time have this distortion.  I wonder is it because of the tube going bad?




You can try swapping the tubes left to right and see if the distortion changes to the left channel. If so, try new tubes. If not, then others here will have better ideas.


----------



## ForSure

..... I have a brain fart, thanks for your help


----------



## Dimu

After using my Cossor 807 for 3.5 months in the amp I decided to measure tube wear using MaxiMatcher tester. Here is what I got, all numbers relative to how these tubes tested 3.5 months ago:
  
 1. 400 plate voltage with -48 bias
 Transcondactance 95.4% and 97.8%
 Plate current 89.2% and 92.3%
  
 2. 325 plate voltage with -24 bias (this is closer to where these tubes are working at in the amp)
 Transconductance 96.5% and 98.4%
 Plate current 90.9% and 92.6%
  
 So clearly there is some wear, close to 10% looking at the plate current. These tubes started very strong so they might last another year. Really happy the amp only wears out two power tubes at a time. I consider this pair broken in at this point


----------



## 430011

Dimu-
 How many hours do you think you've put on those tubes? I only get to listen infrequently, so I imagine my tubes will last quite a while.
  
 Lately I've been looking for other DIY tube headamp projects, mainly as a diversion. But most of the DIY projects posted seem to be oriented toward low cost, and that seemed counter productive. Alternatively, there are a number of high end commercial tube headphone amps, but I definitely don't have $3K to drop on an amp, especially without the fun of building. So instead I thought I would re-invest into my TU-8200. 
  
 Just ordered a handful of Amtrans AMRG resistors to go into the signal path (including the headphone connection resistors, it felt strange paying $4 for a single resistor). Also, Nichicon gold electrolytics to replace the low voltage caps, a TKD 2CP-601 attenuator (they didn't have 50K so I went with 100K), and RCA jacks to replace board #6 and wire in a signal pad (270K ohms) on one input. After all that I think I may try the PSVANE KT-88.
  
 So Viktor, any news on the Lundahl transformers? They may be too expensive for me, but I am definitely curious.
  
 On another note, I've been listening to a new pair of Fostex TH-610 (25 ohms) with the Elekit and they sound excellent!


----------



## Dimu

Quite a few hours, including forgetting it overnight couple times. Can't say how many hours exactly but those tubes did a fair bit of duty already.
  
 Resistors and caps are important. I would not worry about jacks so much. Output transformers are much more important than jacks. TDK attenuator is what I use as well.
  
 Regarding tubes- 12AU7 does not drive even 6L6GC to full potential in this amp. Upgrading to more powerful power tube does not make sense until you upgrade the driver. Switching to E80CC doubles driver plate size and makes very noticeable difference in sound. But it cuts into your heater power budget. The best combination with stock power transformer is upgrading rectifier and using E80CC with power tubes that consume under 1 amp of heater current. That's why I've been using Cossor 807 for several months.


----------



## Dimu

Regarding budgets- if I were to spend noticeably more money it would not be on another amp but rather on replacing my AMRG resistors with Vishays.


----------



## 430011

Thanks for the feedback Dimu. The jacks are actually not intended as an upgrade, they are just plain jane variety. What I plan on doing is wiring one input with a 270K resistor in series in order to reduce the input so that I can hopefully use a little more of the attenuator range. Trying to do that with board six and the PCB mounted jacks would be a bit of a pain so I am going to remove those entirely.
  
 The KT-88 is just for sound quality, not drive. I wish the amp had far far less power actually. Just in my headphone listening I've found that my favorite combination is KT-88 in triode mode. I'm using Mullard new issue tubes right now, so I thought it would be fun to try a "premium" tube.


----------



## sunneebear

430011 said:


> Lately I've been looking for other DIY tube headamp projects, mainly as a diversion. But most of the DIY projects posted seem to be oriented toward low cost, and that seemed counter productive.


 
  
  
 Have you come across the Torpedo 3 yet?  http://www.head-fi.org/t/781651/torpedo-iii-build-thread


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## 430011

sunneebear said:


> Have you come across the Torpedo 3 yet?  http://www.head-fi.org/t/781651/torpedo-iii-build-thread




I have. No longer DIY unfortunately. I had considered it, but never bought it because I absolutely hate the form factor/esthetics. Now that it's no longer DIY I wish I had gotten one, but I won't shell out the $950 for a built copy with edcors when the kit with Cinemags was $750. It's trivial, but I like looking at my audio gear as well as listening and I couldn't get over that hump before it went commercial. I missed out


----------



## sunneebear

430011 said:


> I have. No longer DIY unfortunately. I had considered it, but never bought it because I absolutely hate the form factor/esthetics. Now that it's no longer DIY I wish I had gotten one, but I won't shell out the $950 for a built copy with edcors when the kit with Cinemags was $750. It's trivial, but I like looking at my audio gear as well as listening and I couldn't get over that hump before it went commercial. I missed out




I came across the Torpedo before the Elekit in my search for a diy tube amp and for the exact same reasons you stated, bought the Elekit.


----------



## Dimu

430011 said:


> Thanks for the feedback Dimu. The jacks are actually not intended as an upgrade, they are just plain jane variety. What I plan on doing is wiring one input with a 270K resistor in series in order to reduce the input so that I can hopefully use a little more of the attenuator range. Trying to do that with board six and the PCB mounted jacks would be a bit of a pain so I am going to remove those entirely.


 
 I would just use an RCA attenuator, no need to change the amp. Besides if you are swapping in a 100k pot it should give you attenuation you are looking for.
 Also keep in mind that as you drive signal down into low millivolts and then amplify it your SNR will suffer. It is better to keep signal level higher and reduce gain.
  


430011 said:


> The KT-88 is just for sound quality, not drive. I wish the amp had far far less power actually. Just in my headphone listening I've found that my favorite combination is KT-88 in triode mode. I'm using Mullard new issue tubes right now, so I thought it would be fun to try a "premium" tube.


 
  
 Just give E80CC a try and see how sound changes. Don't need to turn the volume up to hear it. Going back to 12AU7 just does not sound right, even if it is something like Telefunken 12AU7.


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## 430011

Tube depot has a nice sale on the TU-8200 right now. It would almost be fun to buy a kit and do a fresh build and sell my current amp, but I think I'll just stick with the one I've got and tweak it.


----------



## MLGrado

dimu said:


> Tried 12BH7 again. This time I noticed better bass and I seem to like the sound more. So 12BH7 are staying in the amp for now.


 
  
  
 Hi.  Don't have one of these Elekit, but have seriously considered multiple times.  Probably would have already if not for the fact my current amp is overall extremely similar...
  
 Icon Audio Stereo20 PP.  Its a quad EL84 in push pull, with 12AX7 Driver and 12AU7 phase splitter, solid state rectifier.  As for the headphone jack, it has its own custom winding.  Its a very good headphone amp, with very good speaker transformers as a bonus.. hahaa... well that is the backwards way a radical head-fier would see it, right???
  
  
 Anyway, i am a HUGE fan of the 12BH7 / 12BH7A as a drop in for 12AU7.  Every 12BH7 I have tried competes with or exceeds the performance of the very, very best 12AU7 types.  
  
 The biggest audible difference seems to be distortion.  The 12BH7 tubes are lower distortion, very clear and 'bell like'.  
  
 My current workhorse and favorite is a Rogers of Canada 12BH7.  I believe it is a Sylvania Gray Oval Plate, for for whatever reason this Rogers version sounds particularly better than my other quite fine Sylvania 12BH7 gray plates.  Sylvania had a Canadian plant, I think, and often Canadian made tubes sounded different than their American versions.  Maybe this is the case here, maybe not.  
  
  
 Whatever the case, I love 12BH7.  My favorites in addition to the Rogers are as follows
  
 Raytheon 12BH7A Black Plate with Square Getter
 CBS-Hytron Black Plate with tall Square Getter
 Tung Sol Black Plate
 Westinghouse 'half-wing' Black Plate
 RCA Black Plate... various versions/getters
  
  
 I used to own a few pairs of the Brimar 12BH7 Black Plates.  Sadly, I don't have them anymore, and don't really recall their sound.  
  
  
 Oh, and another good alternative to the 12AU7 that is quite similar to the 12BH7 and usually can be a drop-in is the E80CC.   I have owned the Philips version, but Tungsram made a version that is highly thought of, as well.


----------



## Dimu

mlgrado said:


> Hi.  Don't have one of these Elekit, but have seriously considered multiple times.  Probably would have already if not for the fact my current amp is overall extremely similar...
> 
> Icon Audio Stereo20 PP.  Its a quad EL84 in push pull, with 12AX7 Driver and 12AU7 phase splitter, solid state rectifier.  As for the headphone jack, it has its own custom winding.  Its a very good headphone amp, with very good speaker transformers as a bonus.. hahaa... well that is the backwards way a radical head-fier would see it, right???


 
  
 This Elekit is Class A single ended. Very different than a push pull. Give it a try, it is on sale right now at tubedepot. I am actually thinking of buying a second unit just to have a spare, that's how much I like it


----------



## 430011

I'm so tempted at that sale price. But I don't think I would be able to sell my current one to fund it.


----------



## Dimu

This amp is very very enjoyable and very well built (assuming you do a good job building it very well). You can enjoy it for many years. Do the math on how much that would cost you per month if you use it for 5 years for example...


----------



## MisterPC

Is it possible to buy it built? Or is there someone recommended to do so? I apologize if this was already answered in the 40 pages of this thread.


----------



## Dimu

misterpc said:


> Is it possible to buy it built? Or is there someone recommended to do so? I apologize if this was already answered in the 40 pages of this thread.


 

 I believe you can ask Victor to assemble the amp. I would recommend doing it yourself though- that's what it is designed for. Even if you don't have much experience you'll figure it out easily with this kit and will enjoy building it. All you need is a good soldering iron (I used Hakko FX-600 which is cheap and very good), good solder (63/37 would be my suggestion even though I personally used WBT lead silver alloy), cutters, small pliers, some screw drivers and Allen keys. Rubbing alcohol and multimeter would be useful too. I might be forgetting something but it really is a pretty basic tool set that is required and a few evenings of fun time. If you follow all instructions and carefully watch polarity it will just start working the first time you turn it on. No tuning or adjustments required.
  
 As a word of caution, don't plug it in without cover being fully installed unless you trust yourself to know how to work with high voltages. There are lethal voltages present on the boards and in the tubes. You just have to close the case before plugging it in and be careful not to get anywhere close to the powered tube sockets and tubes.


----------



## JK-47

I just finished installing a set of Mundorf Supreme Evo silver/gold caps into the TU8200. 

Wow, immediate difference in clarity and imaging, maybe slightly harsh for the first few hours. They have been playing music for almost 72hours now straight trying to burn them in, and have smoothed out and sound fantastic. Highly recommended upgrade. 

Thanks Victor !!!


----------



## Effusion

Hey JK!
  
 I'm glad to see you did the supreme upgrade and are liking the results!  I too did this upgrade recently and my experiences are very similar to yours; the biggest takeaway for me was also the added clarity and imaging.  In addition, in my opinion the amp now sounds even more natural than when stock, which I wasn't expecting.
  
 Thanks for sharing and I agree, this is a recommended upgrade for those who wish to squeeze a little more out of the stock amp.  For those wondering, all parts can be obtained from Victor and are also included in the Supreme Upgrade option of the DX version when purchased through him.


----------



## MisterPC

Anyone pair a Elekit TU-8200 with KEF LS50 speakers? Thoughts?


----------



## Hifi Boy

Hi everyone!
  
 Got my TU-8200 recently and I'm really impressed by it.
  
 I can confirm that this amp works beautifully with Hifiman HE-1000.
  
 Also, many thanks to JK, for recommending the GENALEX Gold Lion KT66 previously, they changed the sound dramatically!
 The soundstage is much wider and the overall sound is much smoother.
 Bass, not as punchy as before, which is fine, because with the stock tubes I felt it was a bit to much for my (current) taste.
  
 Any other input from JK on what to buy for TU-8200 would be much appreciated.
  
 Since I can't post pictures for now this will have to do.


----------



## JK-47

@ Hifi Boy Congrats on the TU8200
  
 I think yu have me confused with someone else regarding the KT66 Gold Lions. I have never tried them, I have tried the NOS smoked glass GEC KT66 at Effusions recomendation, and they are magnificent, but very pricey.
  
 The Mundorf Supreme Evo silver/gold caps were a very nice upgrade, and bring exceptional clarity and detail.


----------



## Hifi Boy

jk-47 said:


> Power Tubes
> 
> 
> NOS Genelex KT66: Buy them now, or I will. Start hoarding these treasures if you can afford to. A real treat to listen too, simply amazing. Spectacular detail, new layers of sound will smoothly and effortlessly be unleashed upon you if you choose to let these reside in the TU-8200's sockets. A perfect blend of GE 6L6GC (warm low and mid, and Philips 7581A (tight, punchy, and controlled). The only possible downside is if you really start to crank up the tunes and put power down, they start to get a little loose. The Philips 7581A's excel at being driven hard, really hard, but at the cost of lost warmth.
> ...




Hi JK.

I believe this is where I got the idea that you tried the Gold Lion, my bad. 

In any case based on your post I went out and bought the KT66 and I couldn't be more satisfied. Unfortunately I'm not the DIY type, so I won't be installing the Mundorfs. I even bought the amp already built!

I also got the Psvane 12AU7-T2 recently after that, but can't say I felt much of a difference. Although the packaging is nice.



The Genalex Gold Lion 12AU7 are on their way here soon, so I will report back with how I feel about them after I spent some time with them.


----------



## JK-47

I do have a set of modern KT88 Gold Lions, that I use very infrequently. Not really the sound I'm looking for, almost solid state sounding. Some people may like them though. 

A local electronics shop could install the Mundorfs in 30-60 minutes. It really takes the amp to another level.


----------



## 430011

I just received a pair of Gold Lion KT-66 incidentally but haven't rolled them in yet. I also got a pair of NOS RFT 12AU7 that I briefly tried out. Perhaps a slightly punchier sound, but it's hard for me to tell. 

Hopefully I'll get an evening sometime to roll a bunch of tubes in different modes. Interested in these KT-66.


----------



## Hifi Boy

Hey JK, I'm in contact with the very polite and helpful Tamura-san from Elekit, I'm sure they could help me with installing them. 

Also, do you know where I could buy them here locally in Japan, or order them online?


----------



## Hifi Boy

430011 said:


> I just received a pair of Gold Lion KT-66 incidentally but haven't rolled them in yet. I also got a pair of NOS RFT 12AU7 that I briefly tried out. Perhaps a slightly punchier sound, but it's hard for me to tell.
> 
> Hopefully I'll get an evening sometime to roll a bunch of tubes in different modes. Interested in these KT-66.


Hi Evan.

Great to hear that you got yourself the Gold Lions. I can tell you that I did not need any burn in time to be immediately wowed by them. Hope you enjoy them as much as I do.


----------



## JK-47

hifi boy said:


> Hey JK, I'm in contact with the very polite and helpful Tamura-san from Elekit, I'm sure they could help me with installing them.
> 
> Also, do you know where I could buy them here locally in Japan, or order them online?




Oh geez, I didn't know you were in Japan. I bought mine from Victor, the North American Elekit distributor and all around nice guy. I'm sure if you asked Victor he could point you in the right direction.


----------



## Hifi Boy

jk-47 said:


> Oh geez, I didn't know you were in Japan. I bought mine from Victor, the North American Elekit distributor and all around nice guy. I'm sure if you asked Victor he could point you in the right direction.


Hehe, thanks JK, if that's the case then I'm sure Tamura-san should know as well. Thanks for the input!

Could you also maybe describe how the Mundorfs changed the sounds if you have the time?


----------



## JK-47

The Mundorfs pulled a veil off the overall sound and made the it somewhat brighter and more detailed. Instruments and vocals were more distinct and less smeared into each other.


----------



## Hifi Boy

Wow, that sounds just like what I'm looking for. The Fostex HP-A4BL DAC is the weakest link in my system so I was thinking of getting a new DAC. Because I'm just lacking some detail in the sound. 

But now I guess I'll have to try this upgrade first.


----------



## Effusion

Congrats on the purchase and welcome to the club!
  
 I also concur with JK, the Supreme upgrade from Victor does take a bit of a veil off the stock version, adding both clarity and detail; I also noticed a bit of a brighter top-end as well, but after burn-in, etc. it is very pleasant and not overly bright or fatiguing at all, just a wee bit more sparkle up top, which may actually be just better refined detail.  It also sounds more fluid and natural to me as well.  I recommend it to those looking to get a bit more out of the amp in its stock form; it is not a cheap upgrade, but with the prices of NOS, even new, tube sets for this amp, for many I think it would make sense.  Ask Victor for the part list and see if you can source them easy in Japan, otherwise I'm sure Victor can send you them from Canada if need be.
  
 A good to great DAC will definitely give you millage as far as detail/resolution, however it is a large rabbit hole that can really burn-up one's wallet.  It's really about the flavor you seek and the options/functions that you'll use, as many very expensive DACs are really just that, expensive for what you get compared to many others nowadays.
  
 As a side note, I've found that this amp can be very sensitive to what it is being fed and scales nicely to higher-end equipment.  I've even gone as far as moving the signal off my USB bus, my switchable power supply (to linear), and CPU clock due to the amp picking up processing/cross-talk noise within the signal coming from my computer.  I can verify that it was this amp's sensitivity as my other amps do not pick it up, even though it has always been there.  Essentially decrapifying my signal to my DAC enormously affected the Elekit in a positive way and in addition gave me piece of mind.  Everything has become better (really all sonics across the board have improved) and the background is now very silent and black now, even with the pot opened all the way (just some slight tube noise that will always be there).  One of the best things I have ever done to my system, so if you or anyone else is interested in what all I did, let me know (it was quite involved and not very cheap, but I got the best bang for my buck in the end).
  
 As far as tubes go, you can really lose your head with this amp!  For the most part I've only dealt with old-stock, but many here have a lot of experience with new-stock as well.
  
 Enjoy, give it some time to settle in, and let us know how it goes!


----------



## Hifi Boy

Hi Effusion!
  
 Thanks for the reply, I've asked Tamura-san from Elekit Japan, but if she does not know, I will most certainly ask Viktor to send me these. I believe it is also possible to have the TU-8200 upgraded with "Full Set Amtrans Upgrade Resistors Plus", judging by what I've seen here. I'm not sure what these are but if it gives a noticeable improvement in sound quality I will certainly try to get these as well.
  
 Anyway, please do share your experience on reducing the noise. I would like to do the same because it might be helpful, since I'm playing music from a MacBook PRO. On the other hand, my next purchases, will probably be the following ones,
  
 Kimber Axios Headphone Cable (for Hifiman HE1000)
 WireWorld Platinum Starlight 7 USB
 Simaudio Moon Neo 380D DSD DAC
  
 I've tried Kimber cable and can say that I liked it very much. On the other hand, I never tried the other two products but I guess they should bring out the detail in my music.
  
 Any input is welcome.


----------



## Effusion

Those Amtrans Resistors would be a good upgrade, let us know if you decide to go for them.
  
 As far as cleaning up the signal/power from your computer source, there are several options you can go for.  Unfortunately, in my opinion, laptops make it hard to get a really clean signal.  For one thing, the attached monitors can really dirty the power to the rest of the computer, plus since all the components are so close, EMI and cross-talk can be hard to eliminate.  If you are able to go with a dedicated desktop you'll have better options plus a cleaner signal in general.
  
 I'm using a Paul Pang Audio USB card (version 3) that is being feed power from an HDPlex Linear PSU (100 watt).  I use two separate 5 volt rails on the PSU; one runs to the PPA USB card and the other (a USB Type C) runs to my SSD that holds all my tunes.  The nice thing about the PPA cards, besides their great quality, is that they run on the PCI bus, separate from the USB (which runs my keyboard/mouse plus other things when needed).  The card removes all power from the PCI port, only accepting the data, which is then clocked by the PPA card, using the linear power, and then sent out along the USB to my DAC.  This has really cleaned up the signal to my DAC and has eliminated much of the noise, improving the audio across the spectrum.  You can spend a ton of money on Linear PSUs, but I have to say that I was more impressed with the HDPlex than all other components I use, it really is a very nice PSU for the money.
  
 Other than that, I have my computer separated internally by a steel wall, so on one side is my music SDD attached to an anti-vibration mount as well as my motherboard.  On the other side is my switchable PSU (which runs everything but the card and the music SSD) as well as my other non-music SSDs.  Since my case is quite large, the sides are all made of aluminum, so I've covered them in EMI/RFI 3M Shielding to keep the nasties both out and in.  In addition, I currently have 14 case fans (12 120mm and 2 140mm), plus 2 140mm CPU fans which are all PWM fans.  I've programmed them on graphs to increase gradually from 0 RPMs on up according to 10 different temperature probes on both the motherboard as well as different components within the case.  After stress testing my system for 2 hours, running at 4.7 ghz (which is not the max overclock for my CPU, but a safe upper limit), my PWM fans topped out at around 500 rpm, while keeping the processor, motherboard, and all other components extremely cool.  During normal use, the PWM fans run at about 200-300 RPM, which is very silent.  My general rule is the bigger the fan and the more air it pulls/pushes the slower the RPM that is needed, which makes it in turn less noisy; small fans are usually very loud at almost any speed.  They have to be PWM fans however, otherwise the best you can really get is 3 speed non-PWMs and nothing with a gradual ramp-up.
  
 All in all it has been worth it, but if you can't go this route, there are other options including several bridges that will isolate the power and take the music off the CPU clock.  Many people I know really like the offerings from Mutec, although they are not cheap.  However, in the end you are just cleaning up a dirty signal instead of the route I went, which really tries to clean the signal at the source.  The only other thing I've considered is bypassing the CPU clock with an external clock all together, however since I'm effectively negating my CPU clock as the sender with the clock on the PPA card, I don't think it is necessary.  There are also several options to put power filters on the SATA power cables that run hard drives as well as fans (molex as well), but if you separate the music related components from the rest of the system (separate PSUs), than they aren't needed as much, since the motherboard/CPU power that runs the data will always be a bit dirty.  Another thing is to have a nice high quality motherboard; some advertise their shielding and isolation properties, but again these are not cheap as well.
  
 Computer audio can be a big rabbit hole, so tread lightly and follow the general rule that cleaner power and better isolation is the ultimate goal in better audio from them.  Hope this helps to give you some ideas!


----------



## Hifi Boy

Effusion, I have ordered the following from Victor (sadly Elekit Japan does not deal with these parts):
  
 Mundorf EVO Supreme Silver Gold
 Sanyo OS-CON 180uf
 Amtrans AMRS resistor set, 5 Fine Gold 220uf + 3 X 1uf Fine Gold
  
Now I just have to pay off my credit card at the end of the month in order to pay for this (sorry about the wait Victor!) 
  
 You've certainly done your homework on power and noise reduction.
 Since I won't be able to take your route, I'll probably be buying some separate components without modifying my Mac.
  
 So, which products from Mutec would you recommend, since there's a lot of them on their website.
  
 Also, what do you think about Berkeley Audio Design Alpha USB?
 Is it the same as some of Mutec's products, or could you buy that and some of Mutec's products?
  
 The cheapest route I can think of right now to go for me, would be to get Ifi iUsb + iPurifier 2 + Gemini cable.
 Do you have any opinions on their stuff?


----------



## Effusion

Glad you got the parts and are moving forward with the upgrade; it may not be very cheap, but it is worth it considering how much tube sets for this amp are and if you think about it, this upgrade should improve any tube set you use regardless.  Victor is a great guy and knows a ton about DIY and these amps, plus he has a very good ear, so I've always taken his recommendations highly.  Let us know how the upgrade goes and be sure to let the unit burn-in a bit as mine needed it to settle down a bit.
  
 Yes, the best way to improve the sound if you are using a laptop is a quality bridge.  The Mutec units are not cheap, but I believe the best bang for your buck is the MC-1.2 bridge; by buddy is actually the one with the quote on the product information page and he is also here on head-fi, so if you would like to contact him for more information let me know through a private message.  He also wrote a review of this unit on his blog, which is linked by his quote and will probably answer several questions you may have.
  
 The only issue with some bridges is that while they will have a USB connection into the unit, they may not have a USB out of the unit, hence why they are called bridges.  So, if you are using a USB only DAC or just wish to use the USB input on your DAC, you need to be mindful of this and may need to go for a reclocker type of unit.
  
 Unfortunately I don't know much about the the iFi products, but a few of the bigger audio guys around me locally really like the iPurifier and iUSB.  I did look into it once, and there was a nice little unit from Germany that was only about $40 USD that cleans up the USB power, but unfortunately I'm unsure what it was called.  There may be some info on here about decrapifying your signal, so searching would be a good idea, however I do know that other sites have gone a bit crazy over it, with loads of information.  However, I really don't want to link to them here, so if you would like to know, just send me a private message.  In addition, some USB DACs don't need power through the USB signal, while others do because of the "handshake" to trigger the signal connection.  If you are able to find out if your DAC does not need power to handshake through the USB cable, you can actually cut the power wire (not the data) in the USB cable and it will still work the same.  My buddy did this at one point and said the affect was big and along the lines of using cleaner power; you have to cut it at the correct end of the cable I believe, which I forget, so if yours does not need power to start the connection handshake, let me know and I'll ask my buddy.
  
 Generally, what you can do to separate the signal from the computer, either by power or clock, will get you better sound.  However some units may not have dramatic results, while others will.  I know the guys around here went crazy over the Mutec 1.2, ending up on the higher end unit (forget the product model), which some even tweaked and are running with linear power now.  It went from being the best overall upgrade in their system to being absolutely necessary pretty quickly; I just went a different route and couldn't use the 1.2 because my DAC is USB input only, hence why I tried to get to the source (I also do not use a laptop, so this way made more sense).
  
 Hope this helps, but let me know!


----------



## Hifi Boy

Thanks for letting me know about Mutec.
  
 I did some research and from what I can tell MC3+USB is equal to, if not better that Berkely Audio Alpha USB in audio quality.
 Also, here in Japan MC-3+USB is almost half the price of Alpha USB and it also plays DSD.
  
 I think its a no brainer now that I'll go with that after I got my DAC upgrade.
 The Ref10 from Mutec seems to be adding an additional amount of soundstage to the sound, from what I've seen on youtube.
 But this product is either discontinued or it was never released, and I think, it was simply released as Mutec iClock.
  
 On the other end of things, my Genalex 12AU7 came today.
 I can't say I'm noticing much difference from Psvane 12AU7-T2. maybe I need to burn them in a bit before I make a judgement? 
 But as of now, they pretty much sound the same.


----------



## Effusion

Very cool, if I remember correctly, I believe the MC3+ is what those guys ended up with.  It is more expensive than the 1.2, but they were all saying that it was very noticeable difference and worth the extra coin.  Pretty sure they kept referring to the 3 plus or something similar, so I believe this is it.  Seems that Mutec units are also highly regarded by others on the web, so I think they're a good choice.  My buddy has gone through a ton of different bridges over the years, and the Mutec units are pretty much it for him.
  
 As far as those tubes, unfortunately I've tried neither one, so can't really comment on them, but in general, I've experienced greater differences in sound signature with changes in the power tubes, especially from different types that the amp takes, than from 12au7s.  Some of my favorite power tubes for the money are actually the 807 tube types, but you have to buy adapters.  They are pretty inexpensive compared to other quality types for this amp and sound pretty darn good overall (to me between a KT66 and a KT88); I prefer the JAN military types, as well as the ceramic Cossors variant, especially the round plate ones.
  
 To me, most of the time different brands of 12au7s give me only small differences in color and tone.  Using different types of input/signal tubes, such as 12au7 equivalents, has always given me more differentiation than within the exact 12au7 family.  Not to say that the input/signal tube is not as important as the power tubes, because once you get one you really like. it brings the entire amp together and can make it really shine.
  
 Any particular sound that you are looking for overall or that you would like more of?
  
 The folks here have a ton of experience with tubes in this amp, both old and new, so let us know how it goes and if we can help.


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## Hifi Boy

Well, for now, I'm done with buying tubes. I can't complain about the sound they gave me,
 or the awesome upgrade the KT66 Gold Lions were. The sound I'm looking for is warm, lush and smooth.
 This is exactly what I got from the Genalex and Psvane.
  
 On the other hand, you really made me think about the Mutec stuff now,
 because I need more detail in my sound since I have enough of warmth.
  
 Seeing as how the Simaudio 380D DSD is not a small investment, I might just go for the MC-3+USB for now.
 I would just need a quick clarification on your part regarding how to plug it into my system.
  
 The Fostex HP-A4BL which I currently have looks like this.

 The Mutec MC-3+USB looks like this:
  
  

  
  
  
 So, as far as I can tell, the only way to connect these two is to use the S/P-DIF optical connectors which they both have.
 But I've read that this type of connection is not the best in terms of audio quality. Do you think it would make sense to use it this way?
 Or these might not be optical connectors at all? I have no idea since I never used this connector before.
  
 Once I've upgraded to Simaudio 380D DSD, then the obvious choice is the AES/EBU connector, but for now It seems like I'm stuck with his one.
  
 Aside from this I do have another question. From what I have seen, the Mutec website lists MC-3+USB in almost all the categories,
 except Audio/Video Clock Generators and Sampling Rate Converters. Under this category we have MC-4, MC6 and MC-8 products.
 Can you tell me what these are and would they be a worthy upgrade together with MC-3+USB?


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## Effusion

Sounds like a good plan.  DACs are very important, but a cleaner signal will help any DAC.  Better quality DACs will show these improvements more, so once you upgrade you'll know that you are getting the best signal that you can from your new DAC.
  
 As far as I can tell from the pictures, yes you'd want to use the optical input/output between the two.  So, USB into the Mutec, optical out of the Mutec, and finally optical into the Fostex.  The USB on the Mutec appears to be bi-directional, so you could also use it as a USB out at some point, but would have to come from either the Coax or Optical out of a motherboard.  If it had two USBs, one input and one output, I could have used it with my setup and a lot of others could have as well.  Maybe one day...
  
 While there are quite a few folks who do not like optical, I think you'll find that you can really find about the same amount not liking USB nor Coax as well.  There are strengths and weakness to all of them, so it's important to understand each.  I believe the biggest issues with optical have always been both the connectors and the material.  Generally the connectors are very cheaply made and not just on cables, mostly on equipment; while the Mutec connectors are probably high quality, the ones on say your motherboard or even some DACs may be low quality.  Some who are fans of optical only use the best (most expensive) optical cables so that jitter creation is non-existent.  Small timing/registering delays can occur within optical due to how the light diffracts and travels at different wavelengths, so it can mess a bit with the clock's timing and/or the signal.  However this is usually pretty small and just the fact that you are using the clock off the Mutec unit instead of your CPU, negates a large part of potential jitter into the DAC's stream; CPU core clocks are not only clocking your audio, but everything else your computer is processing as well, so compromises have to be made sometimes.  One plus to optical is that EMI/RFI doesn't really interfere with it and degrade the signal.  Some out there claim that glass is better than plastic and that certain cable lengths should be used.  There are some merit to these various opinions, however I've never really been an optical guy, more coax and now USB, so unfortunately I can't help much.  If you are planning on upgrading the DAC soon, try to get the best bang for your buck popular optical cable out there for your current DAC, so you have more to put towards the new DAC as well as options for selling it once you do.  Unfortunately I do not know what that cable is nor where to find out.  You also could wait until you get the new DAC, using the money that would be going to the Mutec for it and then getting the Mutec at a later date afterwards.  I'm not sure how many of the Mutec units come up for sale, but finding one used in that time could always be an option.
  
 Hope that helps a little bit more.  Contacting Mutec with some of your questions prior to buying wouldn't be a bad idea.


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## Hifi Boy

WireWorld optical cables are around 20,000 yen here. Not too expensive, so I see no reason why I couldn't take one for now if I decide to go with Mutec first.
  
 After I get my parts from Victor and other upgrades we've discussed I think I'm done with digital upgrades for a while and will start concentrating on the analog side of things. I believe that Fujiya Avic has a repair shop at the same place where they sell the headphones so I might try to get them to install these parts into my Elekit.
  
 I must say that I am happy with how it sounds after I've added Gold Lions KT66, but if you and JK both agree that Mundorfs will give me more detail, then I certainly won't complain! 
  
 Could you also tell me how exactly does the Amtrans affect the sound? In the same way as the Mundorfs, or is it different? Do they give you more detail or something else entirely? What about the soundstage and imaging?
  
 One more thing, now that I know how to clean up the USB signal (Mutec MC-3+USB), could you also tell me what would be the easiest way to clean up my power supply? What I mean is, something that's not DIY solution, but a simple purchase.


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## Effusion

Yup, all you would need in the short-term for the Mutec would be a cable like that, with good value to sell down the line.
  
 Let us know how it goes with the supreme upgrade.  Unfortunately, I can't really comment much on the Amtrans versus other components in particular; I had all of the upgrades I've done in two separate occasions and I was unable to actually use the amp for a while in-between the installations.  To me, the supreme upgrade package gave me more resolution, however the affect isn't huge or anything like that, just better definition and to me more natural flow with added clarity; a bit like a refined signal tube that brings it all together, rather than an entirely different tube set which does not sound the same; it helps by processing the stream better so that the sound of the amp can be at its best.  Let us know your impressions pre and post go as well.
  
 There's probably a lot you can do to improve the resolution and detail of the sound, but in the end it really all comes down to having two components, of which you really have to like and enjoy in the long-term.  These are both the source and I what I call the ends.  Nowadays with Flac and other uncompressed media types, also ultimately due to how the actual recording was recorded/mixed, in a way the source has become more of your DAC nowadays than the digital file, as well as in a much more controlled way than almost anything above it in the stream.  We can't really change the actual source, how it was recorded/mixed for the studio/live recording, neither can we affect the sound other than to use the best uncompressed technology around, so in a way the DAC is now the area we have control within. Finally, it ends with your speakers or often, such as in these cases, headphones, as the ends.  So, in my opinion, you will always get the best sound by using the best to you in both the DAC and the speakers/headphones and to your preferences.  Not that the in-between doesn't matter, it's actually very important, as it is the actual journey of sound right.  It is also the reason why all of us really like the Elekit TU-8200; it makes the connection of your DAC to your headphones amazing and with enough tweaks to really have your fill.  As in many ways, all this in-between is really just getting the signal through the path from the source to the ends, however I think we can all agree that it is how you do it that makes all the difference.  In one way, units like the Mutec, as well as the path I took, go one step up closer to the real source, beyond where the DAC sits, where we still actually have some influence on the sound, better stated as better control on what influences the DAC.  Cleaning this area of the chain, which essentially feeds your DAC, will only help everything downstream... ultimately.
  
 However, in my opinion, I think you'll probably get better millage in the short-term out the benefits of a new DAC.  Now, whether that's prior to or after a Mutec unit, is entirely up to you, but I think you'll get a bigger impact out of a DAC first.  Unfortunately, a lot of what one ends up buying with the higher-end DACs nowadays is really just more resolution in most cases.  I've had the pleasure of hearing several very expensive DACs throughout the years and most of the time in the end it came down to both resolution and detail for those that were priced far/beyond what is average.  There are a ton of great DACs out there, so you really want to find one that both works well with you and more importantly, has the sound you are after.  If detail is the ultimate for example, the sky can really be the limit.  Even on the other end, the actual ends of the chain, in this case our headphones, you can and many do go there as well.  There are some really nice, but very expensive electrostatic setups out there that can get you some amazing resolution in the mids, etc.  So, essentially while the Mutec would help you now as well as in the future, it's overall benefit is probably more like the supreme upgrade in the Elekit to a new quality DAC upgrade in regards to overall impact; the Mutec is just letting your DAC do its very best, how your DAC does this is really up to it.   A new DAC, one that you really like, should give you more of a dramatic difference, while the Mutec will only really help it out that much more.  Often many higher-end DACs tend to be more sensitive to dirty power and signals than you would think; the higher the resolution of the DAC, the more impact a clean power/signal solution will tend to have because it will show more of the actual changes and in more detail.
  
 As far as more resolution out of the TU-8200 amp, besides upgrading components, different tube types/variants could also help in some of these areas.  I've tried a few rare 12au7s and also the Telefunken Diamond smooth and ribbed plates, which were all very good as far as detail and resolution.  Some of the power tube types can also help out as far a detail in the mid-range, including a few such as the EL34s, that many here really like.  As far as newer production, the Psvane brand is regarded as being very detailed, which you have some of already.  However you choose to go, there is quite a bit of experience with tube-rolling this amp within this thread, so let us know if you have any questions regarding different types.
  
 As far as cleaning up the power supply, unfortunately it may be very hard to do with a laptop.  You can run your entire laptop using a Linear Power Supply unit that feeds into the laptop's charging port (not sure with Apples though, but probably).  However the computer is still going to throw all of its garbage down into the current stream that feeds your DAC anyway.  One benefit of Linear power is that it has a very small to almost non-existent amount of ripple on the rails, however, dirty power in is still dirty power out in the end.  Don't get me wrong, it will have a benefit, but probably not as large as other possibilities.  However, I don't think you need to worry as the Mutec unit is powered separately (power-cord of your choice) and since it re-clocks your signal, I believe it is probably stripping away the computer's power signal and/or enhancing with it's own somehow.  Power regulation is usually a main focus in units such as these.  In a way, looking at both the external linear power supply for use with a laptop versus using the Mutec with a laptop, the Mutec probably makes the most sense, mainly because the components aren't on separate power supplies to begin with, if you only run in a linear current line into the laptop charging port.
  
 I hope this doesn't create too much more to think about!


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## Hifi Boy

Well, it actually is a lot to think about but, I'll deal with it. 
	

	
	
		
		

		
		
	


	



  
 I've done some research, and it seems like PS Audio PerfectWave 3 would be a good power supply for start.
 Not to expensive, but has some really good reviews.
  
 Regardless of whether I go with Mutec or DAC first (I've already decided its going to be Simaudio Moon Neo 380D DSD), I need to get some good cables. I've tried Kimber Axios at the last Fujiya-Avic show and they were amazing. What I will also need from Kimber is an adapter, since I'll be getting a 4-pin cable but with an adapter to the 1/4" jack. In my opinion it should be terminated with a 4-pin connector for a future amp, but currently, I need a 1/4" for Elekit.
  
 I don't know whether you ever had a chance to listen to any Mass-Kobo products, but their Model 394 (540,000 yen) is by far the best amp I've ever tried. And yes on the same day, at the Fujiya-Avic show, I've tried the almost 4 times more expensive Goldmund HDA Telos 2. As far as I can remember, Model 394 was not as holographic, but it was more pleasant to listen to. This is a solid state amp but sounds like a tube amp with great punch, smooth sound and incredible detail.
  
 But it has to be taken into account that I've only compared Model 394 to the stock Elekit. I'll have to hear it again and compare it with my Elekit which now has Gold Lion tubes and will soon have Victor's upgrades.
 Will it still be worth to get the Model 394 then? I'm not sure, but we'll see.
  
 What I'm also interested are other tube amps, for example Eddie Current ones. Unfortunately I never tried any of them. From what I've read the Balancing Act and the Studio seem to be the end game amps for sure.
  
 As for the Elekit upgrades, as soon as they arrive, I will let you guys know what I think of them.


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## Effusion

Okay, I see where you are going now, a general power supply and not one for your computer exclusively.  Yes, PS Audio does have some really nice power supplies and power conditioners.  In my opinion they can sometimes be a bit too high in price, but many like them.  I would suggest using it with only your audio equipment plugged in and having your computer on a different circuit if possible.
  
 The Mass-Kobo looks very nice, I've never heard one before, but it looks very interesting.  I would give the Elekit a chance though, it truly is a great amplifier for the price.  The right tube sets are also very important to get the sound you are seeking.
  
 As far as cables, I haven't sunk a bunch of money into them, opting mostly for hospital grade power cords and bluejeanscable.com products, so I can't help much here.  However, be mindful that there are a ton of really expensive cables out there and not all of those that are expensive sound the best in every system.  For detail, generally silver give the best, while they may sound a bit thin and bright at times.  Generally copper provides a ticker, warmer sound, but not always.  I actually really like the solid copper with silver coated on the outside hybrids, they tend to give me the best of both worlds, with the least amount of negatives usually associated to each.
  
 Adapters can be useful at times when you have cable misconfigurations, at least in the short-term.
  
 As far as Eddie Current amps go, they are awesome!  The one that I really like, I mean really, is the limited Studio amp by them.  It is definitely the best amp out there I've heard period, especially because every set of headphones I've tried with it sound the very best I've ever heard them.  This includes several headphones I use exclusively with the Elekit, the Studio is better.  Simply superb amplifier.  Other offerings from them are nice as well, but some I think are a little overpriced.  The Zana Deux or the Studio for me as far as they go and from what I've heard.
  
 Keep us up to date on the upgrades and any other questions you may have.


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## Hifi Boy

Wow, you actually heard The Studio?
  
 It was my opinion that this was a very rare amp and not many people have had the chance to hear it. 
 Could you please let me know, when compared to a much cheaper and upgraded Elekit, how do these two stack up?
  
 I mean, I know that Studio is better, I don't doubt that for a second. But how much better and how exactly better, is what I'm interested in? Because if I'm ever going to update to this amp, it would sure be helpful to know since its is $7000 that I will have to fork over for one. Also, have you had the chance to hear the Balancing Act?
  
 I can tell you for a fact that I'm very happy with my Elekit. But also can't deny that I would like to have Mass-Kobo Model 394 and Studio if I could.


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## Effusion

Yup, and on more than one occasion.
  
 Yes, I believe it is a very limited release, so many who have very much wished to hear it have been unable to.  On both occasions it simply beat all other amplifiers I've tired personally.  With both my HD650s and Custom Beyers, the experience has been absolutely sublime.  In fact, it has run every headphone I've thrown at it the best that I have heard.  Easily beating not only the Elekit, but many other amps that are no slouches.  The second time I heard it was better than the first, since the tubes were changed to ones with better characteristics overall in my opinion, but were very expensive.  That's the thing, not only is it not cheap, the tube sets are also very expensive.  To me, it does everything very well, but with a natural ease of presentation that is in my opinion hard to match.  Not only was it detailed like crazy, probably one of the best I've ever heard as far as detail, the sound was never clinical, dry, or bright; I actually found it even more natural than other amps that are known to be very organic and thus, less detailed.  The sense of presence is amazing and the sound-stage is just about perfect for most purposes.  I really can't think of any real negatives about it in fact; the best of just about everything I would say in relation to the Elekit and much more expensive units than the Elekit.
  
 I don't think the Elekit could ever be as good, no matter how many parts you upgrade, however for the price as well as all the company's research/design that went into the limited unit, we wouldn't really expect it to.  The real question is at how much cost as a ratio to the performance gained is there with it.  The Elekit and others get you fairly close, for a fraction of the price.  In addition, those extra little bits of pure delight that the Studio possess come at an exponential cost when compared to great value and nice sounding amps.  So, one must ask themselves, how much is 20% better worth?  How much for 30%?  How much for only 5% more?  And so on... don't get me wrong, if I had the money or was given one for free I would gladly use it.  However, since I really like all the tweaks you can do to the sound with the Elekit, I would honestly actually keep this amplifier in addition to it as well.  However I am one that likes to change the sound signature from time to time to fit certain needs/moods, so I would also still use the Elekit in some way.  That would be perfect, both a Studio and an Elekit TU-8200... what more could I ask for!
  
 EDIT:
  
 Unfortunately I haven't heard the Balancing Act from them yet, but it sure does look very nice!
  
 Also, as far as a more direct comparison to the Elekit, I would really need to spend some more time with the Studio and actually with it in my setup.  Overall the Studio is better in my opinion, but I would need time to evaluate the Elekit amp to it using different tube sets as well as modes in order to be fair on how I judge the individual characteristics.  However, I think the choices the TU-8200 provides would allow you a possibility to be able to extend and/or even enhance the sound in certain areas over the Studio, or in your own opinion just better than the Studio at times; very much like a different headphone paired with the Studio would sound compared to others (I'm sure they all sound amazing though).  For example, you could extend the soundstage or change the EQ of the TU-8200 with a different set of tubes, even changing the output mode in addition, which at times will also change how the tubes respond to throw even more in the possibilities mix.  All of this gives a ton of different potential options to match your headphones to your DAC in the ways that you see fit or enjoy.  Plus, I wouldn't feel comfortable upgrading the components inside the Studio (they don't need to be anyways), so the Elekit is just easier to adjust in these areas as well as others.  However, the TU-8200 would probably not come very close in several areas compared to the Studio in the end, which in turn would make it much harder to audition between the two because automatically the Studio has an advantage with the synergy it has shown me in the past.  However, if you really like your headphones as well as your DAC and you don't mind messing around with the amp or trying out different tubes in it, then the Elekit TU-8200 can really be a lot of fun!


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## Dimu

misterpc said:


> Anyone pair a Elekit TU-8200 with KEF LS50 speakers? Thoughts?


 
  
 Works well for me.


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## MisterPC

dimu said:


> Works well for me.


 
 And...? Any details that you care to share?


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## Hifi Boy

A quick update before the end of the year! 
	

	
	
		
		

		
		
	


	



  
 I've just purchased WireWorld Platinum Starlight 7 USB 1.5m cable and I can confirm,
 that right out of the box you can hear slight difference from my stock Fostex HPA-4BL DAC cable.
  
 The cable has not been broken in at all, and the differences are not dramatic.
 I would only say that you can hear a slightly fuller bass reverb and that there is a bit more presence to the sound overall.
 Basically its more in the nuances.
  
 The bass is tighter and the decay of drums and cymbals is longer and their imaging is more pronounced.
  I've certainly noticed more details using the PSB7 cable, than with the stock cable.
  
 For example, in 192khz version of Keith Greeninger & Dayan Kei - Looking for a Home, I have only now noticed that this is a duo,
 not a solo performance which starts with Keith Greeninger at 0:29 and then Dayan Kei joins close to end of 0:29, moving into 0:30 sec.
  
 I have never previously noticed this section at all, and always considered this part to be performed by Keith alone.
  
 So, I can confirm that the cable at least pulls my attention to detail which I did not notice before. Is all of this a placebo effect,
 I certainly cannot tell for now. Will have to give some more time to break the cable in, and then I'll give my final judgement.
  
 Also, I'm not sure whether Fostex HPA-4BL DAC is even able to reproduce properly the additional signal which is supposedly brought by PSB7.
 It might be the case that with a better DAC, the sound scales much more.
  
 For now, I will just conclude with saying that the perceived changes to the sound, which in my opinion make this cable,
 if nothing else, more transparent that the stock cable, even if they are minute.
  
 Tomorrow I'm probably going to be receiving another piece of gear which I recently ordered, so stay tuned for an update.


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## Effusion

Congrats on the new cable, it looks like a really nice one!
  
 Crazy how even USB cables can affect the sound.  With most cables, the connectors can make a huge difference, as well as how they are manufactured.  However, compared to other components, in my experience cables typically provide the smallest differences compared to other upgrades, similar to tubes in a way, such as different 12au7s in the TU-8200.  A great cable, with really good connections, will tend to affect both the imaging and sound-stage in a positive way, with silver providing a bit more detail and copper providing a bit more warmth in addition.  Also, in my experience power cables provide more of a dramatic difference than most interconnects.  Of course your mileage will vary; I think once you get a new DAC, trying this cable against another cheap cable will show even more of a difference than with the Fostex DAC.  More revealing DACs tend to be more sensitive to the cables connected to them.
  
 Let us know how the rest of the upgrades go!


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## Hifi Boy

Hi Effusion.

Happy New Year!

Yes, the cable does make a difference but for now it's quite small.
I'm hoping, as you said, that with a better dac it will be more noticeable. Also, I'm still waiting for another piece of gear to come in so please, stay tuned!


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## Hifi Boy

One more update, before the real gear arrives. 
	

	
	
		
		

		
		
	


	



  
 I've received the Mundorf capacitors today and I can't wait to try them out!
 Also, Victor suggested I buy the Amtrans resistors directly from Amtrans since I'm here in Tokyo, which is exactly what I'm going to do.
  
 Anyway, I'll let you guys know what I think of the upgrade as soon as its installed into my Elekit.
  
 Thanks for sending these Victor!


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## Hifi Boy

Finally, after almost 3 weeks, my MUTEC-MC3+USB has arrived! 
	

	
	
		
		

		
		
	


	



  
 Please keep in mind that my Elekit is being upgraded, so I will write a detailed review after I get it back.
  
 For now, let me just say that through the Fostex it sounds amazing.
 The detail is through the roof and if I had only one word to describe the sound it would be - REAL.
 The music now simply sounds more real and the instruments are much better defined in space than previously.
  
 I have no idea what I can expect when the Mundorf/Amtrans upgrade arrives but I believe it will be amazing!


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## Effusion

Glad you are digging the Mutec!
  
 They are great sounding units and you went with one of the better units they offer.  Although my setup is different, my conclusions are very similar to yours and now after going through it as well I believe that cleaning up the signal is almost necessary when using a computer.  The hard thing is when everyone is using different setups; some laptops, some desktops, some servers, etc.  However, they are probably all just messing up the sound in some sort of a way and in the end, and in their own way.  It would be cool to see more reviewers using units such as these to at least try to level the playing field more, especially with DACs.
  
 One way to think of it is if you were layering fabric mesh over a tweeter, each layer dampens the sound coming from the tweeter and in a way you end up losing both the fine detail as well as what I like to think of as the presence of the sound.  The fine detail gets washed out and the presence of the sound gets over-saturated with background variances/noise to essentially drown itself out.  In a way these pieces of fabric are similar to when we introduce or produce interference within the signal, just small layers of degradation that we can peal back in a sense with units such as the Mutec 3.1+.  You could also put digital jitter into this category as well.
  
 So, in a way, units like the Mutec allow us to at least begin to get closer to just the tweeter and nothing in-between.  I believe that every time we really mess with the signal, either when changing characteristics, paths, and even types of signals, these very small nuances of detail/presence, that collectively make the music sound more real, may be degraded and even lost.  The reason why tubes sound so nice to many is because of distortion, but not like we normally perceive it.  Distortion in the higher level harmonics, such as that produced by tubes, to me add their own flavor of presence to the sound and also to many, make the sound more natural.  However, other types of distortion are unpleasant and are to be avoided.  These revived nuances not only improve the resolution, as we are closer to the original, but they give us a sense of the sound that is sometimes missing, but unfortunately is very enjoyable.  From the very slight plucking of an instrument to the background noise of a crowd, the presence of the sound allows us to feel like we are witnessing the moment with the music rather than having to inherently accept that it was conducted in the past and we are only a mere witness of this past.
  
 It would be really cool if Mutec made some smaller units, with just a set of USB in/outs as well as options for AES combos.  If they still used the core components, such as in the 3.1, but removed all other connections and lowered the price, I think they would do quite well.  Maybe an option of an in/out clock as an add on.  I think quality cheaper and smaller units, but more geared toward the mass home-audio market than the pro, would be useful to many.  As our understanding and implementation of USB as become so much better as of late, having all those other options that drive up the cost when most newer DACs have pretty good, at least responsive, USB inputs, would be probably be pretty popular.  Anyway, I think this is just the beginning as far as products like these go.
  
 In a perfect world, I would have a dedicated solar panel network connected to quality batteries and the using pure sine wave inverters to be pushed out to certain audio dedicated rooms.  This is ultimately isolating the entire signal of your sound; away from your house, your neighborhood, and the grid itself.  However, I would even like to see in the near future, that is as we become better with batteries in general, small components acting like a rechargeable power bank paired with a type of pure sine wave inverter, and all prior to the conversion of DC for use.  Essentially removing all components from the noise of the grid in a way, but that still provides constant power (maybe a bit of a warm-up time).  This is a bit far down the road though and would only be for audio dedicated components.
  
 Let the new Elekit amp components burn-in a bit before concluding, I think 20-30 hours should be good.  I found that the sound smoothed out about then and has stayed fairly constant since; at first you may find the highs a bit bright and the sound just a little sharp overall in general.  This all seemed to go away after a bit of run time, but the detail, air, and imaging stayed.
  
 Only gets better from here!


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## Hifi Boy

Hey Effusion!
  
 Thanks for recommending Mutec to me, I must admit that this was a good purchase. The unit itself is not cheap but for the price it does give good results.
  
 I do have some other questions.
  
 Once I've gotten myself a new DAC, I believe I'll go with the PerfecWave Power Plant, mainly because I'm running out of wall sockets in my apartment. 
  
 The thing I would like to know is once I buy that power supply, I believe I should also get a power conditioning cord, probably will go with WireWorld Electra.
  
 So my question is, do I buy just 1 power cord which will go from the wall to the power supply, or should I buy a power cord for each and every audio component? The latter approach seems to me to be prohibitively expensive. I'm not sure whether the result of the initial power cord will be nullified by the stock power cords which will go from the power supply to the audio components.
  
 The second question is with regards to the pure sine inverter you just mentioned. I researched a bit and found that it transforms the signal to look more like a real sine wave as opposed to a more on/off signal.
 I'm not sure how exactly this would impact the audio quality, so could you elaborate on that? Also, I've seen some models for $100-$200 on Amazon, do you think these would give good results or should I go for more expensive ones?
  
 I also assume, that only 1 unit would be needed which should be plugged into the power supply?


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## Effusion

You're very welcome and I'm glad to try to help.  I agree about the Mutec units, a better signal, is well, just better.
  
 As far as getting a good clean supply of power, it can be difficult, especially if you are connected to other units in your apartment complex.  Not much you probably can do, but unplugging things and even using some DIY hacks like socket plugs, etc. have helped some, but these are usually smaller in impact than most tweaks.  The biggest culprits of messing with your power are usually fridges, microwaves, etc., so definitely try not to have the audio on the same circuit as the kitchen.  I actually use a quality power extension cord to a different circuit/room that isn't being used than where my computer is located.  I also use a ONEAC unit that my computer, monitor, modem, etc. are all plugged into.  If you can find one of these units (they may be discontinued), or one like it, they can really help isolate the dirty power output from your computer and other non-audio directly components, making sure it doesn't go back into the circuit; this is especially true if you are using plugs in the same room, etc.
  
 The PerfecWave Power Plant does look very nice and I like what it is doing at lot.  However, I've never used one and I don't know too much about the impressions of with and without one.  I guess my suggestion would be to try to get a ONEAC or similar unit, plug everything but your DAC and amplifier into it and if feasible, run a quality extension cord from a different circuit/area that has nothing plugged in.  Then, either now or later, get a unit like the PerfecWave Power Plant to plug just the audio, non-computer, components into.  Some power conditioners are very nice and they are widely used by many, but considering how your power is at the source, your mileage may vary due to other conditions out of your control.  A few I've known have ended up recently selling very expensive conditioners, saying that they took some of the life out of the music and now they prefer high quality surge/power protectors instead and a more direct path.  Since you are in an apartment and can't control how other units use their power, your local grid is already probably a bit dirty and there may not be much you can do expect use something like the PerfectWave.  I don't really know much about different conditioner units, but I do know that some aren't very good or at least for how much the sell for; I personally use a high quality surge/line protector for all my audio gear and a large ONEAC unit for everything else.  A new DAC upgrade beforehand will also probably give you more impact in the end than trying to do much else beyond the Mutec.  However, a unit such as the PerfectWave could get you one step closer.
  
 As far as power cords, they are important and do change the sound; more in my opinion than most interconnects, but usually smaller changes overall.  I haven't dove into the world of cables so much, at least yet, so I've mainly opted for hospital grade power cords with thicker wire gauges.  Since these cords send the power to very expensive and highly accurate hospital machines, they are usually of very good quality and I've even had good experiences comparing them to much more expensive cables.  There is a lot of variability in cables.  In the past, the easiest way to tell if a cord was hospital grade was a small green sticker on the inside of the plug.  However, I would not trust this completely and a cord with a sticker targeted towards audio could be a fake.  Otherwise, there are a lot of different types of power cords to choose from, many with big price tags, so take this into account.
  
 Good power cables would be good for all components though, but if you are using a conditioner unit, the plug from the wall to it would be a good place to have a quality cable I would say.  At least it wouldn't hurt.  I don't know much about those conditioning cables, but they look very nice.  You could go with one of those, or something similar, and then a few nice hospital grade ones from a good seller as a start.
  
 As far as those pure sine wave inverters, it just something I would go with, or maybe something similar, if I had no restrictions and was running off a separate solar grid and storing DC.  It really has to do with Modified vs Pure Sine Wave Inverters, but I am no expert on the subject.  Actually most often a pure sine wave is used because some equipment won't actually run off a modified, which can produce hum as well as other distortions, so I believe they have become the norm.  The idea being to take the DC from the solar panel batteries and creating a clean AC current with little distortion or added noise, so something like these units compared to modified units makes more sense.  So, these would take the DC and turn it into AC, but something like the PerfecWave Power Plant may also be doing something very similar, so it would be a better choice if going from an existing AC source than DC storage, as you would need things in addition to the converter.  Here is a link to some information, but I haven't really looked into it much and something else may be a better.  For your purposes I wouldn't worry about trying one so much as a ONEAC and/or a unit like the PerfectWave.


----------



## Hifi Boy

I can't wait for my Elekit to arrive. The guys at Amtrans said it will take about 2 weeks to get it done. So that would mean 2 more days. I assure you I'll take 30 hours of breaking everything in before I post any reviews.
 Interesting article about the sine wave. Here's what it says on PS Audio's website, at least for Power Plant 10:
  
*Capable of powering any size system with pure sine wave power...*
  
 So it seems it acts as a pure since inverter as well.

 I'll have to look some more into that.
  
 As for the power cord. I just realized that the Japanese distributor for WireWorld does not carry Wire World Power cords. I've contacted WireWorld about that but still didn't get a reply. 
	

	
	
		
		

		
			




  
 I've also realized what a mistake I've done with purchasing the 1.5m WireWorld cable. I should have bought the shortest, 0.5m one.
  
 A much better solution for my system would have been to have my MacBook on the audio rig itself, meaning I could simply use the 0.5m cable, and then use an external monitor (which I intend to buy anyway) and use a mouse and keyboard (which I already have) on my desk.
 Unfortunately I wasn't thinking yet I could have saved myself a lot of money.
 Hope somebody learns from this mistake. 
	

	
	
		
		

		
		
	


	



  
 As for the other upgrades, there still one more piece of gear which I should be getting at the end of this month. I'll certainly let you know what it is when it arrives and how it works with my Elekit. 
	

	
	
		
		

		
		
	


	



  
 I would like to ask you also, what is your opinion on DACs. have you ever hear Chord Dave, because I have. I would say that its very smooth, which I like a lot. Unfortunately, I have not heard it with my Elekit, but through its headphone port, which I kind of consider a waste. Not that there is something wrong with it, but in my opinion, such high-end DACSs should't have any headphone outputs, since it goes without saying that if you can afford such a DAC, then you probably can afford a decent amp as well.
  
 Which brings us to my situation, which is that I can't afford such a DAC, thus I was thinking about going with Simaudio 380D DSD. My question is, what DACs would you recommend and how do they compare to Dave, if you've heard it before?


----------



## Effusion

Very cool, let us know how it goes!  After it burns in, do some comparisons without the Mutek in the path as well.
  
 That P10 Power Plant looks really cool!  Yup, actually right along the lines I was commenting on, the unit stores the AC as DC and then converts it back to AC using a sine wave inverter of some sorts.  Essentially very similar to what a dedicated solar panel setup I referred to would do, without the need for the sun/panels, but the grid.  Those aren't cheap though, but boy do they have a ton of features, best to find used and used with lighter equipment... I would be interested in how they affect the sound and what people's general impressions are.
  
 No worries, it is hard to predetermine all of your uses and a longer cable is probably better than one that is too short in the end, as long as you have room for the cable, etc.  You could always sell it and then buy the shorter one, however it may only make sense to buy a short one used then as well.  Or you could just use it and who knows, maybe the extra length may come in handy later on.  I've found that to be true with RCA cables at least and trying to do different runs turns out to only work in a few placements.
  
 As far as DACs go, in my opinion it is a giant hole of possibilities.  Not only are there a ton of different options out there, they all do the conversion in a slightly different way as well.  You can always start at the individual DAC chips, however in my opinion and in more ways than other audio components, DACs can vary greatly due to implementation alone and not just the chip.  So, two of the same DAC chips won't necessarily sound the same in two different implementations/units at all and some chips that may be regarded as just okay by most are actually quite good if implemented in a certain way.  In addition, really being able to tell the differences between DACs is not as easy as say headphones for most.
  
 I haven't heard the Chord Dave, but it sure looks crazy!  Very cool, looks sort of like an intercom from the future!  I know a few guys that really like some of the Chord stuff and I believe there is some good buzz around a few of their products currently, so I'm sure it is very nice.  For the price, we would hope so!  Unfortunately I haven't heard the Simaudio unit either, but it looks very nice as well; lots of connections available.  I agree about the headphone out, pointless at that price point and if not done correctly can cause interference with the DAC, so really shouldn't be there and only ups the cost, but they probably wanted the total-package unit, so they included it.
  
 Although I can't help much with those two DACs, I would suggest that you try to purchase something used.  I went through a bit of a DAC search myself and buying second-hand units saved me a ton of money.  If you are unsure, it is nice to know that you can get around the same amount you paid back in the end if you don't like it.  I personally haven't gone through a ton of DACs myself, but I know a few guys that have gone through dozens over the years.  Although it is harder for newer or rare DACs to come up for sale, patience can sometimes save one's wallet in the end.
  
 I personally prefer the sound of well implemented NOS DACs.  There are several reasons of why and what I prefer about the NOS sound, but implementation is critical.  NOS is hard because often they sound too veiled, dark, and soft, but there are quite a few out there that do things very well.  Ultimately it is about the sound you prefer and the functionality contained within.  I like NOS for not only the sound, but I also believe that the way we up-sample and over-sample currently can sometimes put a digital edge on everything and kind of mess with the sound a bit.  The technology is cool, but in my opinion we just aren't there yet.  I think we first need to record and master in high-definition very well and not just rely on changing the sampling and resolution of low-res material.  Getting everyone there is the problem.  How the over-sampling is done also varies greatly and some do it very well, while others, mostly in the past, not so well.  If you are into hi-res recordings than there are quite a few options that are absolutely amazing.  We have come a long way in the recording department and I've heard quite a few very nice oversampling DACs in the past few years, so eventually I'll get there.  The key to me is those that not only get all the recorded detail out, but present it in a way that is never harsh or abrasive, but natural and inviting.  You could compare this digital edge I hear in some DACs to some of the new 4K TVs out there right now.  They look great with non-4K stuff until you see something extremely detailed and then the edges just get really sharp; the best way to see this is when there is text on the screen and it is moving either in or out of the frame, the borders of the letters become razor sharp and personally hurt my eyes after awhile.  Also, fast sports filmed in 720 don't look so great and get muddy as well as all mushed together.  Audio and video are different, but this is just an easy comparison.  To me, many times NOS DACs smooth out everything as well as do it in a natural sounding way and if you don't have hi-res recordings they are feasible.  To me, they can help make a studio recording sound more natural and not so boxed-in as well as a live recording sound more believable.  However, it does help that I don't currently have any hi-res music, so I really have no use for a hi-res player and considering my tastes, NOS just makes more sense for me.  It's also not like I could just go out and buy the hi-res download, which often is just converted from redbook anyway, because it is unavailable and probably will be for a long time considering I listen mostly to independently created/sold music, not on any major labels.  In the end, some of the high-resolution recordings I've heard recently through hi-res equipment blew me away, so eventually widespread use on both ends will be the norm.
  
 My best suggestion regarding a DAC is to read a ton of reviews/impressions and put together a top three list based on how you perceive they may sound in your system and the necessary functions for both now and in the near future.  Then check for nice used units at good prices; if you can get a unit from the original buyer it is best, but often you'll be either the third or fourth owner.  If you can get one for a good enough price to sell back later, try it out and if you don't like, oh well, just try and find another different one on the list for sale, etc.  This way you can "really" try a few (with your own equipment) that you want to, all in your own system and without breaking the bank in the end.  It is really a waiting and luck game though, so it is always best to try what you really want regardless in the end, but the trick to saving your wallet is getting there in the fastest and cheapest way.


----------



## Hifi Boy

I've been doing some research lately and now I'm also considering the Invicta Mirus. Even though its around 700K yen here.
  
 I've read nothing but praise for this DAC and its been made by the guys who made the Sabre DAC chip in the first place! I don't think you can go wrong with that.
  
 There's a review which says that the USB isolation on this unit is great and that using BADA Alpha USB didn't add much to the sound.
  
http://www.highfidelity.pl/@main-469&lang=en
  
 So, I think that my Mutec won't add much to it either. On the other hand Mutec is planning to release Ref10, which then should be able to make some noticeable difference in sound.
  
 One other review compared Mirus with Meitner MA-1, which here costs more than 1.1M yen, and concluded it was the preferred device.
  
 As for my Elekit, I believe 2 weeks are up today, so I should be receiving it shortly. I'll let it break in for 30 hours as you've suggested and then do a review. After the review, I'll listen to it without the Mutec to determine what exactly have Mundorf+Amtrans added and what exactly has Mutec added to the sound quality.
  
 Also, I'll probably be doing a review of WireWorld Platinum Electra 7 cable soon. Haven't decided on that yet, but I do believe I'll have to take my Elekit with me to make sure what I'm hearing there is what I'll be hearing at home. I've also been thinking about the PerfectWave power regenerator and the power conditioning cords in general.
  
 I don't really know what these power conditioning cords are supposed to do, but to my mind, whatever they are doing, I do't think it would make a lot of sense to put one between the wall socket and the PerfectWave.
 Since PS Audio website clearly states that the AC power, which is coming from the grid is regenerated, as in, created anew, by coverting it to DC and then again to AC. So any effect, which the conditioning cord might have on the electric current should be nullified once it gets regenerated. They specifically mention that PerfectWave Power Plant is not a conditioner but a regenerator. Conditioning is in that case only done by the cord.
  
 In my mind then, I believe the cord should be placed between the PerfectWave and the devices, to keep the electric signal as pure as possible once it leaves the PerfectWave and enters the audio components. If I have only one such cable, I believe that the device which is most sensitive to electric power should be connected to it, which I think would be the amp.


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## vkung

This is the little brother of TU-8200
 It has the same features of TU-8200 with  6AQ5 (6V6) X 2 + 12Ax7 X1


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## sunneebear

vkung said:


> This is the little brother of TU-8200
> It has the same features of TU-8200 with  6AQ5 (6V6) X 2 + 12Ax7 X1



Hi Victor,
TU8150 right, how much will it cost? As a headphone amp only, can it sound better than the TU8200?
Thanks


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## vkung

It is around $475.  
 TU-8150
 Tube set : 6005W (6AQ5) X 2 ( 6V6 can be used ) + 12AX7 X1

 Output mode : UL (2.9W), Pentode (2.9W) and Triode (1.6W)
 Speak impedance : 4 - 8 ohm
 Headphone : 8 - 600 ohm
 TU-8200 is the big brother of TU-8150...  TU-200 has more juice..


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## Dimu

misterpc said:


> And...? Any details that you care to share?


 
  
 Not sure what kind of details are you looking for? I use LS50 for near field listening on my desk. Cossor 807 in UL mode power it more than adequately, sounds gets to unhealthy levels before audible distortion creeps in. I feed it with Gungnir Multibit DAC and the whole system is very sensitive to signal quality. For example I used it for a few days without Regen and the sound was noticeably grainy. But then again my TU-8200 and TU-8500 were built with the best components from the ground up. The only expense spared is that I used very few naked Vishay resistors. Pretty much all resistors are Amtrans, as many of them as I could get are AMRG. Bypass caps have significantly lower ESR than the best upgrades offered by Victor. Mundorf caps throughout including where they don't really fit physically. Upgraded power caps. TDK pots. Silver lead solder from WBT. The only thing that I still would like to upgrade further is output transformers. And of course tube choices are important. I still did not get to upgrading my power transformer so my amp keeps running Cossor 807s driven by E80CC. This is the best combination that I found that is compatible with the stock power transformer. TU-8500 is running a pair of Mullard 12AT7. All original tubes.


----------



## Hifi Boy

While breaking in my upgraded Elekit, I stumbled upon this website where they reviewed many capacitors and ranked some of them higher than the top Mundorf models. For example, has anyone ever heard about this one?
  
*Intertechnik Audyn True Copper Max MKP 630VDC*
  
Do you guys think this would be able to be installed into TU-8200?
  
 Dimu, you seem to have upgraded your Elekit extensively. Could you let me know what else is there to be added, besides the Mundorf capacitors and Amtrans resistors and where could I get those upgrades?


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## vkung

Those caps are too big for TU-8200. Mundorf Silver Gold is good for TU-8200


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## Hifi Boy

Hey Victor.
  
 Thanks for letting us know. What about this EAT KT88 Diamond tube here?
 It seems quite expensive and has good reviews online.
  
 Do you think it would work with TU-8200?
  
 One more question.
  
 I'm currently 25 hours into breaking in the Mundorf and Amtrans upgrades.
 How long do you think it takes before they sound their best?


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## vkung

I think 20-30 hours..
 I recommend you to replace the driver tube to Psavne Mark II 12Au7 or *Brima 12AU7*/ECC82. I like  EH6L6GC..


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## Hifi Boy

Hey Victor, as you can see, from this post I already have the PSvane tubes. 
  
 While I was at Amtrans store, I did see some RCA ones, which I heard were also very good and hard to find.
  
 I might consider auditioning them in the future.


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## vkung

RCA  6L6GC is very good.. I like 6L6GC,,
 I will use Psavne MKii KT88. It is around $200.


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## Hifi Boy

Ah you mean the large ones.
  
 So, while at Amtrans, I also bought Gold Lion KT88, they only had 1 last pair left.
  
 Do you know how do they compare to PSvane KT88, have you had the chance to try them?


----------



## Dimu

> Dimu, you seem to have upgraded your Elekit extensively. Could you let me know what else is there to be added, besides the Mundorf capacitors and Amtrans resistors and where could I get those upgrades?


 

 Victor has TDK pots, they fit and are very good. Bypass caps are important too, you can get upgrade from Victor or go shopping for lower ESR ones.
  
 When you install Mundorfs make sure to observe polarity. You can use an oscilloscope to figure out which end should be facing in which direction. You can look at upgrading other caps, like power caps for example. I used some automotive high temp caps in there, as well as some Silmic II.
  
 Upgrade the rectifier feeding DC heaters for the driver tubes, I used 3A if I remember correctly. Then stick in a pair of E80CC.
 And get good NOS output tubes like RCA 6L6GC or GE 6L6GC or Sylvania 6L6GC. Or get Cossor 807 with round plates and adapters for them. Keep away from those anode caps and wires in the adapters though as there is high voltage present there, not shielded by the amp case.
   
If you want to go really deep into this then order power transformer with bigger heater secondary and use it to run hotter tubes like KT88 for example. I am talking about real KT88 of course, made in England by GEC, or TT21 with adapters.

  
 In either case keep E80CC for drivers- that makes more difference relative to any 12AU7 than any upgrade of output tubes with 12AU7.
  
 Ask Victor for output transformer upgrade 
  
 If you want more 2nd harmonic distortion then get a TU-8500, upgrade its pot, caps, resistors and tubes and then run it at max volume. I changed negative feedback in mine by using different resistors. If you don't want more 2nd harmonic distortion then don't bother with TU-8500, unless you want the phono preamp.


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## JK-47

Which Mundorf caps have polarity? I thought the Silver Gold Evo Supreme caps had none...


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## Hifi Boy

Hi Dimu.
  
 So, the things that I could get now are:
  
 - TDK Pots
 - Bypass caps
 - Output Transformer
  
 Mundorfs I already got from Victor. I got them installed at Amtrans shop here in Tokyo.
  
 As for the rectifier, I'm not really sure what that is or where to get one.
  
 I've heard that RCA tubes should be really good. I'm talking about the small ones that go in the front, don't know the name for that. Currently I'm using Psvane 12AU7-mk2, and also have Genalex Gold Lion 12AU7, I can't really tell there is any differece in sound. Do you think a certain type of RCA tubes would be even better than these two?
  
 Regarding the large tubes, I was using Gold lion KT66 until recently, which in my opining is just amazing compared tot he stock one, but when I got my Elekit upgraded I also bought Gold Lion KT88. I'm not sure, but as far as I've heard KR Audio Tubes should be the best out there. I recently found KR Audio KT88 on this website. They are quite expensive so i'm not really looking to getting them just yet.
  
 I did not see them on the official KR Audio website so I sent them a email about it and they confirmed that they are real. 
	

	
	
		
		

		
		
	


	



  
 As for the 2nd harmonic, if that's the thing that makes the sound warm and smooth, than yes, that is what I'm looking for. But I'm not sure whether to go with TU-8500 because I'm thinging of stopping with digital upgrades after I get a new DAC and concetrate on analog upgrades. Then I'll probably get Luxman's EQ-500 and PD171A, so I don't think it would make much sense to invest in TS-8500 right now, even though i've thought about it.


----------



## Dimu

jk-47 said:


> Which Mundorf caps have polarity? I thought the Silver Gold Evo Supreme caps had none...


 
  
 Does not matter if it is Mundorf or not. Cylindrical caps are rolled as many layers- this is how cylinders are formed. Then one lead is attached to the internal end and the other lead is attached to the external lead. Not exactly "polarity", maybe "orientation" is a better term to describe this. That external layer acts a shield for coupling electrical fields so it is best to connect it towards the end of the circuit that has lowest impedance to ground.


----------



## JK-47

Interesting, this is the first I've heard that, regarding cylinderical caps, unless the have the polarity marked on them. Why would cap makers not make this difference easy to identify?


----------



## Dimu

hifi boy said:


> Hi Dimu.
> 
> So, the things that I could get now are:
> 
> ...


 
  
 I did not say you can get an upgraded output transformer from Victor, I just suggested that you ask him for one 
  
 The "small" tubes are driver tubes and the "big" tubes are output tubes. Driver tubes pre-amplify the signal so that output tubes can operate in the optimal range and do their amplification job.
  
 Rectifier you can get from any electronics store or distributor. For example mouser or digikey. Notice you can't use tubes like E80CC with KT66 or KT88 because you will burn your power transformer. You would need to upgrade your power transformer if you want to use E80CC or other driver tubes with higher heater current together with high current output tubes. Which is why I would stay away from anything other than 6L6GC or 807. Rectifier is easy, power transformer not so much.
  
 Also notice that when you say that you use "Genalex Gold Lion" you quite possibly likely mistaken. Most cheaper tubes are made in Russia and China. Real GEC tubes can cost $1000 for a pair of output tubes, if you can even find them. I don't understand why people buy Russian and Chinese tubes with fake labels. It's like buying fake Rolex watches- what's the point? I understand when a product is called "psvane" or "kr audio" or "svetlana" or "jj", etc. But Genalex or Mullard or Telefunken or Tung-Sol I don't get. None of those tubes were ever made in Russia, USSR or China, and for good reasons. If you want try to a proper Soviet tube try a pair of real MELZ 6SN7, they work well in TU-8200 once you get adapters.


----------



## JK-47

@Hifi Boy I would slow down with the upgrades and sit back and enjoy your amp for a while. otherwise you will never truly appreciate the money spent. Also if you keep on spending , you would probably have been better off with another higher end amp in the first place... Happy Listening !!!


----------



## Dimu

jk-47 said:


> Interesting, this is the first I've heard that, regarding cylinderical caps, unless the have the polarity marked on them. Why would cap makers not make this difference easy to identify?


 
 Apparently they used to mark them and some still do, Mundorf does not though. Just tune oscilloscope down to max sensitivity set it to a few ms per division and then attach the cap to the probe and hold it in your hand. You'll see induced voltages on the screen, most noticeably 50/60Hz, sometimes other stuff, even into MHz range if you speed your scope up. Then flip the cap and see whether amplitude went up or down. When it is down the  ground lead of the probe is connected to your external layer. Point that towards ground or for C3/C4 point towards points 5/6 and for C9/C10 point it towards points 7/8.


----------



## JK-47

What will happen if you do not orientate the caps this way?


----------



## JK-47

Can you post a pic of your caps installed?


----------



## Hifi Boy

@DimuQuote:


> I did not say you can get an upgraded output transformer from Victor, I just suggested that you ask him for one


 
  Yeah, I think he has some, but I guess I can also get them from Amtrans  since they are 20 min from where I live. 
  
 Quote:


> The "small" tubes are driver tubes and the "big" tubes are output tubes. Driver tubes pre-amplify the signal so that output tubes can operate in the optimal range and do their amplification job.
> 
> Rectifier you can get from any electronics store or distributor. For example mouser or digikey. Notice you can't use tubes like E80CC with KT66 or KT88 because you will burn your power transformer. You would need to upgrade your power transformer if you want to use E80CC or other driver tubes with higher heater current together with high current output tubes. Which is why I would stay away from anything other than 6L6GC or 807. Rectifier is easy, power transformer not so much.


 
  Ok, got the point. Stay away from stuff I'm not too familiar with, or I'll burn my amp!
  
 Quote:


> Also notice that when you say that you use "Genalex Gold Lion" you quite possibly likely mistaken. Most cheaper tubes are made in Russia and China. Real GEC tubes can cost $1000 for a pair of output tubes, if you can even find them. I don't understand why people buy Russian and Chinese tubes with fake labels. It's like buying fake Rolex watches- what's the point? I understand when a product is called "psvane" or "kr audio" or "svetlana" or "jj", etc. But Genalex or Mullard or Telefunken or Tung-Sol I don't get. None of those tubes were ever made in Russia, USSR or China, and for good reasons. If you want try to a proper Soviet tube try a pair of real MELZ 6SN7, they work well in TU-8200 once you get adapters.


 
  Honestly, I'm new to the audiophile world and especially tube stuff and Elekit is my first tube amp which I bought just a few months ago. So when I see "Genalex" written on the box, I'll call it as I see it, because I have no idea that its a "fake", as you have put it. 
  
@JK-47Quote:


> I would slow down with the upgrades and sit back and enjoy your amp for a while. otherwise you will never truly appreciate the money spent. Also if you keep on spending , you would probably have been better off with another higher end amp in the first place... Happy Listening !!!


 
 JK, I completely agree with you and I certainly intend to stop... ... ...after I get a new DAC. 
  
 I honestly think that my current one is holding me down. 
  
 I certainly would like to try some other amps, as I said previously Mass Kobo Model 394 was a beautiful holographic experience for me. Also, Eddie Current amps are something that I would like to listen to. It all depends on the sound.
  
 Let me just say that I bought my Elekit the day after I heard it at the last Fujiya Avic show. It had just the kind of sound I was looking for. Big, smooth and warm. On the other hand, few months earlier I auditioned a reference class Simaudio Moon Neo 430HAD and I have to say that even though the sound was good, it was simply not what I was looking for. It was simply too neutral and non-musical for my taste, thus I opted for Elekit. Perfect for studio monitor type headphones and headphone reviews, not so much for kicking back and getting lost in the music.


----------



## Dimu

jk-47 said:


> What will happen if you do not orientate the caps this way?


 

 Induced currents will drain into ground instead of becoming part of your signal.


----------



## Dimu

jk-47 said:


> Can you post a pic of your caps installed?


 
 Don't want to take the case off for that. Caps are caps, installed as usual, just watch which way you rotate them before soldering.


----------



## JK-47

After talking with Victor and exchanging a few pictures, he has them orientated opposite of what you suggested...


----------



## Dimu

jk-47 said:


> After talking with Victor and exchanging a few pictures, he has them orientated opposite of what you suggested...


 
  
 I am pretty sure Victor is in the same hemisphere as I am, so induced currents would have to drain in the same direction- towards lower impedance relative to ground.


----------



## JK-47

Ok, fair enough. I'll by an oscilloscope and figure it out my self. 

Hers is a good reference regarding inner and outer capacitor foils. 
http://jimmyauw.com/2010/04/24/observing-inner-and-outer-foil-of-some-popular-capacitors/

By the way the Mundorfs do have a shorter lead indicating the outer foil. I was certain they were the same length. Anyways it has been a learning experience. Too bad you don't care to share too much @Dimu

http://www.mundorf.com/en/?category=hifi&menu=caps_audio&content=mcap_supreme_evo_silvergold


----------



## MisterPC

dimu said:


> Not sure what kind of details are you looking for? I use LS50 for near field listening on my desk. Cossor 807 in UL mode power it more than adequately, sounds gets to unhealthy levels before audible distortion creeps in. I feed it with Gungnir Multibit DAC and the whole system is very sensitive to signal quality. For example I used it for a few days without Regen and the sound was noticeably grainy. But then again my TU-8200 and TU-8500 were built with the best components from the ground up. The only expense spared is that I used very few naked Vishay resistors. Pretty much all resistors are Amtrans, as many of them as I could get are AMRG. Bypass caps have significantly lower ESR than the best upgrades offered by Victor. Mundorf caps throughout including where they don't really fit physically. Upgraded power caps. TDK pots. Silver lead solder from WBT. The only thing that I still would like to upgrade further is output transformers. And of course tube choices are important. I still did not get to upgrading my power transformer so my amp keeps running Cossor 807s driven by E80CC. This is the best combination that I found that is compatible with the stock power transformer. TU-8500 is running a pair of Mullard 12AT7. All original tubes.


 
 Thanks for the reply! What's your opinion about using the combination in a 15x18' room though with a lot of resonance? High wood ceiling, wood floor, drywall. I have a small upright piano and the sound is enormous in the room. A pianist listening from outside street remarked that it sounds like a grand piano. So, although the room's size seems to be of a concern, its  sound handling is quite efficient. In using the LS50's with the TU-8200DX, if I want to turn it up sometimes for early Elvis Costello, say, am I going to be disappointed? 
  
 For reference, in my office, I have JBL LRS 305 monitors on my desk with volume controlled by an SMSL SD793-II and for me, this would actually be plenty of sound for the larger room; actually it's a bit more than I need for this sizable office. Based on your description above and mine here, you can see I have very little knowledge. Your input on this would be appreciated. I bought the LS50 speakers when they were on sale. Haven't used them yet and won't even get my hands on them for a bit; unfortunately, I won't be able to sample amps.


----------



## Dimu

misterpc said:


> Thanks for the reply! What's your opinion about using the combination in a 15x18' room though with a lot of resonance? High wood ceiling, wood floor, drywall. I have a small upright piano and the sound is enormous in the room. A pianist listening from outside street remarked that it sounds like a grand piano. So, although the room's size seems to be of a concern, its  sound handling is quite efficient. In using the LS50's with the TU-8200DX, if I want to turn it up sometimes for early Elvis Costello, say, am I going to be disappointed?
> 
> For reference, in my office, I have JBL LRS 305 monitors on my desk with volume controlled by an SMSL SD793-II and for me, this would actually be plenty of sound for the larger room; actually it's a bit more than I need for this sizable office. Based on your description above and mine here, you can see I have very little knowledge. Your input on this would be appreciated. I bought the LS50 speakers when they were on sale. Haven't used them yet and won't even get my hands on them for a bit; unfortunately, I won't be able to sample amps.


 
  
 In addition to room, speakers, amp, signal source, etc, there is one more hugely important component that will affect the answer to the "are you going to be disappointed" question- and that is your brain. In fact it is two "brains"- your actual brain in terms of how you process signals from your ears and your "mind" brain in terms of your expectations. So I don't think anybody but you can tell you whether you will be disappointed.
  
 Since you already have LS50 ordered look at it this way- TU-8200 drives LS50 to unhealthy levels before it starts clipping. Unhealthy means that if you sit 3-4 feet away from the speakers you get over 90 dB of sound pressure delivered to your ears. So I would say go for TU-8200 if you already got LS50. If you want more sound then you need bigger amp but I think you also need bigger speakers too, like something floor standing with multiple cones. So either get TU-8200 or get rid of LS50. Does that help? 
  
 P.S. when you get TU-8200 you can try running LS50 with 4Ohm setting at the back of TU-8200. I did it both ways and there is no harm, so you can choose which one you like sounding better. Keep the amp in UL mode though for what you are trying to do.


----------



## Dimu

Re-tested my tubes that I've been using in my TU8200. E80CC after over half a year of use show remarkable consistency- all parameters tested the same across all four triodes. Cossor 807 are showing a bit better parameters than 3 months ago but still noticeably weaker than 6 months ago. Not sure how to explain that- first it dropped after three months and then recovered a bit after three more months. Those tube started unusually strong though, so they are still testing much stronger than other Cossors that I have.
  
 Summary is that after half a year of use both E80CC and 807 are very solid and give me an impression that they can last for many years in TU8200.


----------



## Dimu

Big ass transformer installed, sort of. Need to do more machining to close the case. I may be biased, but I have an impression that sound became deeper with the same tubes just by swapping out power transformer. It is possible as the core is much bigger on this sucker. It sounds so awesome that I don't really have any desire to try higher power tubes which is why I got that transformer in the first place...


----------



## Dimu

GEC TT21. Really nice especially if you like deep bass but I think big transformer made much more difference to Cossor 807 than stepping up to TT21.


----------



## Dimu

Telefunken made in Berlin. Not sure how to describe but these sound different, like they have very different frequency response. Higher frequencies are much more prominent it seems. Very nice but different. Will have to stick this into a spectrum analyzer one day to figure out what the difference is.


----------



## Dimu

GEC KT66. Simply awesome but I would need to spend a lot more time listening to figure out whether I prefer this GEC, the other GEC or Cossor.


----------



## Dimu

GE 6550. After listening to GECs, Cossor and Telefunken I am not impressed.


----------



## Dimu

I think TT21 is my new favorite. It has what Cossor 807 has, but more of it.
 There is another problem however- I am afraid of closing the amp because both power transformer and the board run noticeably hotter than with smaller tubes. Especially the board is hotter, all the way to 63C where it says "danger high voltage".


----------



## JK-47

How about a pic how you have the capcitors mounted now that you have the amp apart? For the benefit of the entire TU-8200 community.


----------



## Effusion

vkung said:


> This is the little brother of TU-8200
> It has the same features of TU-8200 with  6AQ5 (6V6) X 2 + 12Ax7 X1


 
  
 Looks great and I like the form factor; small enough to fit just about anywhere, yet able to drive near-field single drivers as well.  I'd be curious as to how it compares to the 8200!  Thanks for sharing Victor, I will be keeping my eye on it.
  
 Dimu, thanks for all the pictures and impressions!  One of these days I'll have to do similar mods to run some of these.  I agree about the KT-66, I've found them to be quite nice, preferring my GEC Smoked Glass the most; my buddy agreed as well.  I also really enjoy the 807s.  Some of my favorites have been the Hytron Smoked Glass, the JAN types such as Sylvania/Westinghouse/GE, and a few of the European manufacture such as Siemens/Mullard.
  
 I actually just picked up a pair of earlier AT-25s, round plates, saucer getters, and ceramic bases; very nice indeed and great sound all around!  Below are a few pictures (although taken in low light)...
  



  
  
 Keep 'em coming and I'll try to snap a few more photos as well as add some impressions soon.


----------



## Dimu

Those are Cossors, probably the best match for this amp in its stock form. Based on my measurements if you pick up a good pair of Cossors they will last you a long time.
  
 I've been comparing Cossors to TT21 without top cover and it seems like the amp is not designed to run higher power tubes despite manual saying KT88 and 6650 are ok. Things heat up noticeably more, including the core of the power transformer. The hot spots are the two power mosfets driving output tubes. I think I'll take my amp further apart to see if I can do something about those two mosfets- maybe even move them off the board to give them better thermals. The mosfet for the left tube is actually worse off than the right one because it is tucked into the board and airflow is more restricted there. I can't imagine what temperatures will be inside if I close the case. Mosfets might be able to take it for some time, but it won't be good for the rest of the circuitry including caps. Elekit did too good a job packing this thing into a small case. If they made it more loose it would have been better for upgradability and passive cooling. Another alternative would have been a case with aluminum fins but the kit would cost much more if they went that way.


----------



## Hifi Boy

@Dimu
  
 KT66, my love, without a shadow of a doubt.
 Beautiful sound at least compared to the stock ones you get with TU-8200.
 Currently I have 75 hours on my Mundorf capacitors and 24 hours on the new Kimber Axios cable I got last week.
  
 I can highly recommend the cable and can vouch that the cables certainly do make a difference.
 Not just in some areas but across the board improvements.
  
 Take for example *Anne Bisson - September in Montreal*.
  
 The beginning of the song, and the first several solo piano keystrokes are incredibly smooth, soft and so "round".
 We could say that the entire performance is exceedingly pleasing to listen to, like a veil has been lifted.
 The sound is clearer and even the soundstage gets wider.


----------



## Effusion

dimu said:


> Those are Cossors, probably the best match for this amp in its stock form. Based on my measurements if you pick up a good pair of Cossors they will last you a long time.
> 
> I've been comparing Cossors to TT21 without top cover and it seems like the amp is not designed to run higher power tubes despite manual saying KT88 and 6650 are ok. Things heat up noticeably more, including the core of the power transformer. The hot spots are the two power mosfets driving output tubes. I think I'll take my amp further apart to see if I can do something about those two mosfets- maybe even move them off the board to give them better thermals. The mosfet for the left tube is actually worse off than the right one because it is tucked into the board and airflow is more restricted there. I can't imagine what temperatures will be inside if I close the case. Mosfets might be able to take it for some time, but it won't be good for the rest of the circuitry including caps. Elekit did too good a job packing this thing into a small case. If they made it more loose it would have been better for upgradability and passive cooling. Another alternative would have been a case with aluminum fins but the kit would cost much more if they went that way.


 
  
 I've been really digging them so far and I got them new, tested twice, so happy.
  
 Very interesting observations, I too was concerned about both heat buildup as well as airflow within the kit myself.  Since doing the mods, the outside case is much cooler, but I've always wanted to throw some temperature probes down the modded air vent and test the temps running in both normal use and then trying to heat it up.  Unfortunately since I already cut into the steel, I can't really test it without the mod and then compare.  Stock would even be a bit challenging, since you would have to get the probes into the closed case somehow anyway, probably having to use either existing screw holes or by drilling; would have to look into options.  However, with the mod I did linked back here, even the airflow grate I'm using gets warmer to the touch than the surrounding area, so I think some airflow can really help, especially in the long-run as over time the excessive heat can/will degrade certain components.
  
 I'd be interested in what else you are able to find out.


----------



## Effusion

hifi boy said:


> @Dimu
> 
> KT66, my love, without a shadow of a doubt.
> Beautiful sound at least compared to the stock ones you get with TU-8200.
> ...


 
  
 Thanks for sharing, that cable looks very nice indeed and you are right, a quality cable will either lift a veil and seem to "clean" the music a bit or they can also increase both the warmth and/or detail; really good cables also increase/adjust the soundstage.  Some stock cables are pretty good, but most are just okay and there are a ton of really good choices in the aftermarket realm, so they are good options.
  
 Hope you are enjoying all the new upgrades to both the Elekit and your other new gear!


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## Dimu

Very nice looking paint job but I would be careful to make sure the case is grounded. Look how ground is established using star washers at the back of the little board that holds power inlet socket. And you also want to make sure the top is grounded as well. Another good idea is to run it off a good GFCI, especially when you have anode wires hanging out.

My plan is to either move mosfets to the case or add a second pair of mosfets in parallel- this will rebalance currents to achieve maximum heat rejection.


----------



## Hifi Boy

Thanks guys.
  
 As you might have noticed, I'm now using KT88 with my Elekit. I'm currently breaking them in but I'm not really sure how many hours I got on them. I decided to give both Mundorf and Axios 80 hours before I do any reviews.
  
 As for the new tubes, yes I like them, you need to turn the volume up a bit more than what you would normally use with KT66, but from what I've heard they are LESS detailed than the KT66.
  
 I still like them, they are warm and the bass is punchy, I believe the soundstage is wider, but I'll have to check again, because I don't remember anymore. 
  
 Oh, and just so you know, no, I do not have any more upgrades coming my way.


----------



## Dimu

hifi boy said:


> Thanks guys.
> 
> As you might have noticed, I'm now using KT88 with my Elekit. I'm currently breaking them in but I'm not really sure how many hours I got on them. I decided to give both Mundorf and Axios 80 hours before I do any reviews.
> 
> ...


 
  
 You might want to be careful with KT88 as your components inside are slowly cooking with those tubes. Look at the temperature rating of electrolytes you used in the power section for example. Unless you used something like 105C rated automotive caps you are likely exceeding those temperatures already.
  
 Besides your head phones are really, really good (so good in fact that after listening to those I do not want to touch any other head phones). I think your head phones deserve genuine tubes. Real KT88 are available for $750 per pair, and those aren't Gold Lion or Gold Monarch. Real Gold anything are at least $1000 per pair. And you still have the issue with elevated component temperatures inside the amp case.
  
 Try Cossor 807 with round plates. They are cheap, adapters are easy to grab from ebay. Genuine tubes, awesome sound and lower temperatures. And while you are at it grab a pair of E80CC to go with those Cossors and upgrade your rectifier- a quick and easy operation. Those are genuine tubes as well, reasonably priced while they are still available, and they make a huge difference in this amp. Your signal goes via three amplification cascades. Two of them are in the driver tubes and only the final one is in the output tubes. So 2/3 of the signal processing is happening in those little tubes and E80CC are as good as it ever got and they seem to last forever based on my measurements (datasheet says they are rated for 10,000 hours). You can search for ebay seller called euroklang from Germany- he has plenty of E80CC. The best ones have a delta mark on them from the factory in Netherlands, and can be branded Phillips, Amperex, Dario, etc.
   
P.S. don't mix E80CC with KT88 as you would exceed capacity of your 6V secondary on the power transformer.


----------



## Hifi Boy

Hi Dimu.
  
 Thanks for letting me know. I had no idea about how hot KT88 get. The TU-8200 manual clearly says we can use KT88 but I don’t want to take any risks, so I’m taking them out today and putting back in KT66 again. 
	

	
	
		
		

		
			




  
  
 Also, I would like your opinion on whether this goes for all KT88 tubes or just the ones I’m using now?
  
 Basically, I was intending to buy (not now, since I need a large down-payment for a new apartment, so no audio upgrades for a while :/) KR Audio KT88, which could probably be the best KT88 tubes out there. How did I come to this conclusion?
  
 Well judging by the 6moons review, and their statement:
  
*Incidentally, in our personal pantheon of 300Bs so far, we like the KRs best.*
  
  
 I mean if anyone has any experience with tubes and audio equipment in general, it should be the 6moons guys. And if we are to judge by how KR Audio made 300B tubes, then I see no reason why their KT88 would be any worse compare do other KT88s.
  
 I was planning on getting them from here, so please if you can let me know whether I should get them in the future or not.
  
 Thanks for acknowledging the HE-1000’s sound. 
	

	
	
		
		

		
		
	


	



  
 We agree 100% these are also my favorite headphones. Yes, STAX SR-009 are more precise and the sound is clearer than the HE-1000, no doubt about that. But in the same way, the HE-1000 are more musical, and that is exactly why I chose them. I would say that both are very good, but in different ways, I just like what HE-1000 is better at.
  
 As you also might have noticed I bought a 1/4” adapter with the cable. Sure, it was expensive but it would have been even more expensive to buy a new cable when I decide to get a new amp. That’s why I went with 4-pin cable and a 1/4” adapter for the Elekit. I think it makes more sense.
  
 In any case, if I can’t use any KT88s with my current amp, would this rectifier allow me to use them? I believe you said I should ask Victor, right? Also, now that you recommended so many tubes to me, where do I get these genuine Gold Lions that you speak of? As for the E80CC, do you think these could be used as well?
  
 I don't know whether you've noticed but I'm really new to the audiophile world. I always loved music and especially  headphones, just never knew that the audiophile world existed and was never able to afford any of it until recently. My first Audio show was last year's Fujiya-Avic in Tokyo. 
	

	
	
		
		

		
		
	


	




 My headphones of choice prior to that were these:


----------



## Dimu

Took my amp apart to work on the mosfets. This is the how the bottom boards look like. You can see Mundorfs, AMRG, TDK pot, upgraded caps.


----------



## Dimu

This is the top board. As you can see I have a spare Mundorf on hand. The reason is that my four caps did not match close enough so I got another one to decrease tolerances. As you can see from the photo very few parts are from the original kit, especially caps. Silver ones are automotive high temp caps. Brown ones are Silmics. Bypass caps are different to what is included into the kits. Resistors are almost all Amtrans.


----------



## Dimu

Close ups of the power section including installation of high current rectifier for the driver tube heaters.


----------



## Dimu

Mosfets prepared for installation into existing DAC holes, paint cleaned up. 200C rated silicon wiring.
  

  
 Mosfets installed over thermal paste.
  

  
 Radiators at the back, over thermal paste
  

  
 Soldered in to the existing power mosfets for output tubes.
  

  
 Rear mosfets have stabilized at dramatically cooler temperature than the ones on the board. This means there must be more current flowing via the new mosfets than the original.
  
 Driver mosfets are now running hotter than output mosfets on the board. It looks like it makes sense to try doing similar modification to the driver mosfets in order to reduce temperature inside the case.
  
 This initial test was with the stock output tubes that came with the amp. Will have to test with TT-21 to compare temperature to the previous measurements with stock mosfets.


----------



## Dimu

Tried with TT-21, definite improvement in board temperature, now running about 10C cooler than before this upgrade. New mosfets are heating up a bit more with TT-21 than with 6L6, there is clearly more current with TT-21.
  
 Bad news though- those new wires are causing hum. Will have to figure out what to do with that.
  
 Edit: To check for hum I switch the amp to input where nothing is connected and rotate the volume all the way clockwise or counter clockwise. In both positions where volume knob cannot be rotated any further I get hum. In middle positions it is much less pronounced and not as stable.
  
 Unsoldered new mosfets- no hum. Soldering back either one of the new mosfets does not cause hum. As soon as both are soldered I get hum.
  
 Removed both output tube mosfets from the board and just left the new mosfets- hum is much worse in this configuration but board runs much cooler and two remaining mosfets are rejecting heat comfortably via case and external radiators. Next thing I am going to try is shielding those long wires. If shielding works I'll remove all four mosfets from the board- this should bring internal temperatures down significantly.


----------



## sunneebear

dimu said:


> Tried with TT-21, definite improvement in board temperature, now running about 10C cooler than before this upgrade. New mosfets are heating up a bit more with TT-21 than with 6L6, there is clearly more current with TT-21.
> 
> Bad news though- those new wires are causing hum. Will have to figure out what to do with that.
> 
> ...


 
  
  
 Hello Dimu,  
  
 On my amp I tried just lifting the FETs so they stand vertical and mounting a small heat sink but I get hum just lifting them off the board.

 I put them back down and it's dead quiet again.  
  
 I am now cooling my amp another way, only because I want to increase the longevity of the costly caps and resistors.
  
 I drilled a row of small holes in the bottom front of the amp.

  
  
 In the back top I mounted a small 12v fan.

  
 Power to the fan is from a 110v AC to 5v DC cell phone charger.  The phone charger was stripped and only the board was used.  The board was heat shrinked and wrapped with aluminum tape just in case it emitted EMI or EFI.  The AC leads are soldered to the mains board of the amp and the 5V goes to the fan.  The small package was tucked in between the mains board and the case with a piece of cardboard so it won't short anything.  With less than half the required voltage, the fan runs slow and quiet.

  
  
 The amp is now so much cooler than before. The case above the transformer is 42C / 107F and 46C / 115F in between the tubes after and hour of running.
  
 Good luck with your project.  Waiting on your resolution of the hum.


----------



## Dimu

sunneebear said:


> On my amp I tried just lifting the FETs so they stand vertical and mounting a small heat sink but I get hum just lifting them off the board.


 
  
 Nice job on cooling. I don't want to do active cooling on mine.
  
 Trying to heat sink the mosfets inside the case without adding airflow would not make a difference in the closed case- heat would still be trapped inside like in an owen. So you either need to move cooling inside (e.g. air or liquid) or you need to move heat outside which is what I am trying to do.
  
 Thanks for sharing that lifting mosfets creates hum- that is not good news. This means fixing hum might be more difficult than I anticipated. I'll try shielding when the wire arrives from China...
  
 A radical solution would be to move the power transformer into a separate case together with rectifiers and some really big filter caps. It would also require adding one more rectifier for output power tubes. There are safety issues involved in such a project as close to 300V would have to be handed off from one case to the other.


----------



## sunneebear

That would be a project way out of my ability. It is running pretty cool now I will leave it that way. Good luck with yours.


----------



## sunneebear

My latest effort for cooling the FETs
  
 Top side.

  
 Bottom side.

  
 No hum or noise at all.  This will probably be the last time I open the case... until Victor comes out with the new output transformers.


----------



## Dimu

Those radiators won't hurt but also likely won't make too much of a difference as you already have good airflow over the board. There are built in radiators with thermal vias in the board so having airflow should be sufficient to keep things in check.
  
 I've got a configuration without hum using the power of heat shrink. I used just small pieces of heat shrink in the original cable and it obviously was not enough heat shrink so I wrapped the whole thing 
  
 Notice the wire is much longer than the old version and still no hum. I think drilling couple more holes at the rear wall and moving all four mosfets off the board is the next step for me. This should let the amp run comfortably without any airflow (that is after I figure out the mechanical work of fitting my power transformer in a way that will let the case close).


----------



## vinylvalet

I was wondering:
  
 1) The cathode bypass cap upgrade to 180uf conductive polymer caps is just for the 12AU7 triodes? Why not do the same for the output tubes? Why the decrease from 220uf to 180uf? The upgrade caps are also available in 220u, 16V.
  
 2) It seems like changing the B+ bridge rectifier to a Cree high V Schottky bridge (or something similar like Stealth II or HiPerFRED) would be beneficial. Has anyone tried this or can anyone think of any reason not to other than the challenge of fitting all that in?
  
 Thank you.


----------



## vkung

1) The cathode bypass cap upgrade to 180uf conductive polymer caps is just for the 12AU7 triodes? Why not do the same for the output tubes? Why the decrease from 220uf to 180uf? The upgrade caps are also available in 220u, 16V.
    
  
 please refer to page 17 ..C1,C2,C5, C6 .. the rage is between 150-220uf.  We find that  180uf  OS-CON  is the best.


----------



## vinylvalet

Thank you for the quick response. Yes, I saw the discussion on page 17 of the manual.
  
 Why not upgrade the 220u/16V cathode bypass caps on the output tubes as well?


----------



## Andrew Rieger

So is the consensus around here that Triode mode is the way to go? I mainly listen to classic rock, EDM, 80's pop and some jazz. Based on my reading it sounds like Ultra Linear is more dynamic and punchy but less detailed compared to triode.


----------



## Hifi Boy

Hi Andrew, from what I've experienced, Triode mode is indeed better for my tastes.

There is just more presence to the sound and its just smoother and more enjoyable. Haven't tried the Pentode mode yet, but I'm completely satisfied with what I got with Triode mode. UL was too punchy for me. Didn't enjoy the bass at all. It was completely out of place if you ask me. Yes, there is such a thing as too much bass. 

Just give them all a try and decide for yourself.


----------



## Effusion

I also have used the Triode mode the most, but UL has also been nice at times.  I believe many here prefer the EL34 tubes in the UL mode instead of Triode as an example.  Best just to experiment and see what caters to you the best in the end though.  Just make sure you unplug the unit and let it sit for about 10 minutes or so before you switch the connectors.  A few owners have also created really cool ways of switching the modes outside the case in various ways, however you will damage the amp if the switch is accidentally tripped while the unit is running, so this is not advised by Elekit.
  
 As a side note to those that might be interested, yesterday at a local gathering we tried the Focal Utopias on the 8200 and everyone, even the owner of them, thought they sounded just great out of it.  I was off auditioning between two very high end DACs at the time, so I wasn't able to take a listen at that moment, but they thought that out of the Elekit they sounded better than out of most amps they've tried.  This was largely due to the types of tubes I was running at the time in the unit, which was really interesting in the end.  At this time I was running my ATS-25 ceramic base round plate Cossors paired with a very nice pair of Amperex 7316s.
  
 After briefly talking to the owner about his Utopia experiences with other amps (no slouches), I determined that they probably sounded so good because of the tube choices in the 8200 and tested this by swapping in my smoked glass GEC KT-66s.  Sure enough, the Utopias were a bit out of whack and too bright overall, not a good match for them at all.  I don't know much about the experiences with the Utopias, but they seem to be a bit finicky with their amplification.  What was really interesting as well, was that this combo really made my modded HD650s shine and was better than the ATS-25s overall.
  
 Goes to show ya that the types of tubes used with the 8200 really can make a big difference and that the easy tweakability of this amp can really allow one to tailor the sound to their cans as well as their tastes.


----------



## Hifi Boy

TU-8200 could then be characterized as "wire with gain", since the tubes have so much influence on how it sounds. It must have a really clean signal to have it's sound change so much by simply changing tubes.
  
 Anyway, this could probably be the best bang for the buck amp you can get today. Don't quote me on that, it's just a thought. But still, I believe it can be improved. For the next version, I would certainly like to have a fully balanced 4pin headphone output and balanced XLR inputs. Even if that would double the cost, I'd still buy it.
  
 What I also believe, is that Elekit should sell this amp with optional parts like Mundorf caps etc. just like Victor does.
 I know that this doesn't bother you guys that much since you are buying it from Victor anyway and are skilled at DIY but for those who order directly from Elekit and just want to buy the finished product and enjoy the music, it would be a very good approach.
  
 Had this amp been marketed differently, not as a DIY product but rather as a "real" amp, it would be a lot more popular and widespread, I'm pretty sure of that. The 6moons review of it also mentions it competes with amps which are quite a lot more expensive than it, so guys we have a real champ on our hands!


----------



## Andrew Rieger

Does VK Music's $775 price include either of the option packages from this page? : http://www.audioasylum.com/forums/elekit/messages/461.html
  
 Edit: NVM ... Victor is crazy fast with email responses. I'm excited to start my build soon. This will be my first DIY build and my first tube amp. I'm not making things easy for myself but the price to performance ratio is so good that I think I would regret not getting my feet wet in the DIY pool.


----------



## Hifi Boy

And please, change the stock tubes immediately. Preferably go with Genalex Gold Lion KT66. It's a Russian reissue, and as Dimu will be quick to point out, are fake. 

But you will be amazed by what they do to your Elekit compared to the stock ones. Oh, and they're really cheap. Either that or select the Psvane KT88 when you're buying from Victor. Not that cheap but I'm assuming they're even better than the KT66.


----------



## zilkhaw

Hello guys, I am actually trying to find help here.
  
 So I bought my TU-8200 for my HD800 around December 2016 and everything was fine the sound is so nice and I love it so much.
  
 But recently, I start to hear some noise only on my Left channel. The sound persist even when I turn the volume to minimum.
 I tried to interchange the Left and Right tubes and the noise is still available on the Left channel.
  
 I was thinking if HD800 is too sensitive to those noise, so I tried to plug in a cheap earphone and the noise is still very audible.
  
 I have tried to disconnect the input as well, but it did not help
  
 Any pro on this can give me any advice on which part should I look at? 
  
 The problem is not always, sometimes the noise is not there, but most of the time the noise is there.


----------



## vkung

Did you do tube rolling?
if yes, i guess one of the FETs need to replace


----------



## zilkhaw

vkung said:


> Did you do tube rolling?
> if yes, i guess one of the FETs need to replace


 
 Yes I have tried tube rolling.
  
 Thanks for the info, I will try to replace the FET. Is there any major reason on why the FET got malfunction?
 I mean when dealing with the amp, is there any precaution to prevent FET from malfunctioning?
  
 Since this unit is still considered new <6 months and if it is like what you have mentioned, then perhaps there was something that I have done wrong and I should try to be more careful while dealing with them next time.
  
 TU-8200 is my first tube amp, so there are still a lot for me to learn.


----------



## vkung

send me an email
i will send you the parts
a lot of bad tubes in the market


----------



## Hifi Boy

Hey Victor.
  
 I was just wondering, are there any upgrades which could be ordered for TU-8500?
 I'm actually thinking of buying it, but I'm not sure whether I can upgrade it in any way.
  
 Also, if anyone has any experience with this preamp and what you get compared to just having TU-8200, please let me know.


----------



## Andrew Rieger

Has anyone had a chance to compare this amp to the Feliks Elise?


----------



## vkung

TU-8150  with 6V6GT  little brother of TU-8200DX


----------



## Andrew Rieger

Victor, how does the new 8150 sound compared to the 8200?


----------



## vkung

They are quite different.
 TU-8150 can do tube and OP-amp rolling.. $200 cheaper. also less output and smaller.
 TU-8150 can use either 6005 or 6V6.


----------



## Andrew Rieger

Which amp do you think is better if you are only using headphones?


----------



## Effusion

vkung said:


> Did you do tube rolling?
> if yes, i guess one of the FETs need to replace


 
  
  


zilkhaw said:


> Yes I have tried tube rolling.
> 
> Thanks for the info, I will try to replace the FET. Is there any major reason on why the FET got malfunction?
> I mean when dealing with the amp, is there any precaution to prevent FET from malfunctioning?
> ...


 
  
 Were you able to fix this issue?  Any idea what tube went bad and how?
  
 Over the years I've had to replace the FETs on each channel, but not due to normal usage.  My first FET blew because I used a tube type that was outside the specs of the amp, even though online it said it was equivalent to an 807.  The second time was because of a tube the seller sold as NOS, but in reality had a short and they never tested.  Both times the LED turned from blue (where I have it set) to purple.  The first time there was a constant hiss from the channel that blew, no matter the volume.  The second time the channel just went completely dead, no noise, nothing.
  
 Unfortunately it isn't just old stock tubes that can be bad.  A local tube supplier told me that they have a ton of problems with some of the new stock Chinese and Russian tubes, even though they are stated as being tested/matched at the factory.  The owners told me that either they are using very inaccurate test equipment or they are not actually testing them at the factory.  Anyway, most they get directly from the factory are not matched, with even some that are just way off, while occasionally they get some, especially less expensive Chinese, that run fine for a few hours, but then all of a sudden go out.  Thus, part of the service they supply is to test and burn-in each pair, returning the duds to the factory.
  
 So, word to the wise for those opting for even new stock tube sets, try to buy them from a dealer that both tests and burns them in a bit, between 16 and 72 hours should be good enough.  Otherwise, if they are old stock and were tested by the seller prior to shipment, get them tested before completing the sale and try to work something out with them if there is a problem.  Many here have ended up getting testers of their own, since they roll a large number of tubes and many sellers unfortunately are untrustworthy.
  
 I agree, it sucks when a FET blows, but since this is all that has ever happened with a bad tube in my unit, I guess it is better than something else, more major, blowing instead.  The FETs are very cheap, considering, but I also do wonder what could be done to avoid them from blowing in the future.  Probably nothing much in the end, except for testing each tube on a regular basis which can be a pain if you don't have a tester.


----------



## zilkhaw

effusion said:


> Were you able to fix this issue?  Any idea what tube went bad and how?


 
 Hello Effusion,
  
 So Mr. Victor here has been super supportive and trying to help me dealing with the issues. 
  
 I changed my FET and unfortunately it did not work. And by following his advices, I remelt all soldering points and recheck the circuit for short circuit or bad soldering and nothing helps.
  
 I was so frustrated and decided to ask help from Elekit Japan by sending an email to their customer support (I stay in Japan, so I sent the email in Japanese). And to my surprise, the guy who replied was very kind and keep asking me this and that to try finding out the problem.
  
 So eventually I tried swapping (Left and Right) my
  
 - Amtrans Coupling capacitor C3, C4, C9, C10
 - Cathode Bypass capacitor C1, C2, C5,C6
 - AMRA Plate resistors R7, R8, R13, R14
  
 And the noise still stay at my Left channel only. And when I am going to try swapping my tube sockets, my Psvane 12au7 T-II arrived and I plugged them in, the amp just become so silence. XD
  
 So eventually, I found out that both my stock Shuguang 12au7 turned bad already. But I still do not understand why when both of them are plugged into Right channel, they are fine though.
  
 And when I observe the 2 stock 12au7, I just figured out that the base of them have turned black, I don't know why though. Attaching the image for your reference. 
  

  
 So now I am enjoying my TU-8200 happily and considering to make my next step upgrade
  
 - Amstrans AMCO104  to AMCY oil coupling cap
 - The basic 22 resistors to AMRG
  
  
 By the way, after solving the issue, I just realize that the person who was helping me from Elekit Japan was Mr. Fujita himself. OMG, he is such a nice and kind man. 
  
 Eventhough my issue was totally due to the stock 12au7 failure, but I really appreciate the help from Mr. Victor and Mr. Fujita.


----------



## Effusion

Wow!  I'm sorry to hear about all the troubles; must have been very frustrating.
  
 I've never really seen, heard, or experienced anything quite like that.  I did have one 6sn7 that would hiss in the highs in my Darkvoice 336se, but only as long as I used a certain opamp in my tube DAC.  Sounds and looks like something really went wrong with them.  I do recommend exchanging those stock 12au7s right away though for new owners; I don't think I ever used them besides the first time I fired the amp up.  The EH power tubes however are a bit better, a little too loose and boomy, but I never trusted those little 12au7s much at all.
  
 I'm glad to hear you are up and running again.  In the end, it sounds like it wasn't nearly as bad as it could have been if it wasn't for Victor and even Mr. Fujita himself.  The first time my FET did blow, Mr. Fujita had a response back to Victor within hours and I can't say enough about Victor's responsiveness and helpfulness over the many years that I have known him now.
  
 Let us know how it goes and enjoy the new Psvanes!


----------



## JK-47

Victor is a class act that always responds to emails, and is excellent at trouble shooting problems.
  
 Elekit is also extremely helpful and responds quite quickly even though they're half way across the world (from North America).
  
 Between the the two, their customer service is second to none. Thanks for all your help


----------



## zilkhaw

jk-47 said:


> Victor is a class act that always responds to emails, and is excellent at trouble shooting problems.
> 
> Elekit is also extremely helpful and responds quite quickly even though they're half way across the world (from North America).
> 
> Between the the two, their customer service is second to none. Thanks for all your help


 
 I totally agree with you.
  
 This is so far the best customer service that I have dealt with. They somehow not only trying to answer your question but they show their passion on providing more to let customer understand the situation and know more about the product, definitely 5 stars customer service.


----------



## svmusa

I gathered few of you have low impudence phones being used on this amp, curious if this will be able to drive something like JVC HA-SZ2000 phones with 16 Ohms impedance and are typically recommended to be paired with a good power amp such as Cayin C5 that has 800 mW rated output to drive these for showing off their sub bass response. I want to enjoy the bass from the tubes.


----------



## Hifi Boy

Hi svmusa.

This amp is powerful enough to drive mid HE-1000 and it has a great bass.
I highly recommend you get it and you won't regret it.

Just be sure to get rid of the stock tubes as soon as possible. You want get the most of this amp and use it to its full potential. So I would basically suggest you get the upgraded version from Victor to begin with.

I got my Mundorf capacitors from him as well.

As for the tubes, I recently got myself a pair of KR Audio KT88.



A bit expensive but very real sounding tubes. Plenty of bass as well. If you don't want to spend a lot on tubes, yet still have a good sound, go with Genalex KT88.


----------



## Effusion

svmusa said:


> I gathered few of you have low impudence phones being used on this amp, curious if this will be able to drive something like JVC HA-SZ2000 phones with 16 Ohms impedance and are typically recommended to be paired with a good power amp such as Cayin C5 that has 800 mW rated output to drive these for showing off their sub bass response. I want to enjoy the bass from the tubes.


 
  
 While I have never used low ohm headphones for extended periods of time in the Elekit, several owners have reported excellent results using IEMs.  I've tried low ohm IEMs before and I thought they sounded great, so the Elekit could be a good option.  While I do not know the rated output in mW of the 8200 off hand, the headphone section is rated for 8-1000 ohms headphones, so the 16 ohms of the JVC is within it's range.  The nice thing is there are no switches for high, medium, or low ohm headphones, just plug 'n play.
  
 Check out this page of the 6moons review:  http://www.6moons.com/audioreviews2/elekit/4.html
  
 About half-way down the page, the following is stated:
  
_"This pleasant surprise fermented curiosity. A quick check of the schematic (page 19, user manual) revealed that the headphone circuit branches out from the output tubes and output transformers. Three resistors (R39/40, R41/42, R43/44) on each channel readjust the output impedance to suit headphones from 8-1’000Ω. Being a headfi novice, I asked Victor if this was the typical topography for a headphone section found in integrated tube amps. He referred the question to Elekit and the answer came back within hours."_
  
 Also below is the response from Elekit, stated in the review:
  
 "_For those integrated amps with vacuum tubes, there are not many of them with a headphone terminal in the market. Even if they do have it, they usually adopt an exclusive circuit for the headphones which in most cases is solid state. In the absolute sense these headphone circuits cannot realize pure tube sound. For the TU-8200 the headphone circuit is not exclusive and does not bypass the tubes or output transformers. Mr. Fujita our chief designer simply made the headphone terminal an integral part of the tube amp itself, adding only three pairs of resistors to the signal path. This is not as simple as it sounds though. Unlike for solid-state amps, impedance matching is of critical importance for tube amps. Mr. Fujita did not just lower the voltage to maintain compatibility/drive but also had to carefully consider the impedance of the headphones to be connected. He finally optimized the impedance value with minimal components to deliver pure tube sound._"

 Hope this helps, but let us know... maybe someone active here has direct and extensive experience with low ohm headphones on this amp as well.  You can always contact Victor with your questions as well.


----------



## svmusa

Thx Hifi Boy and Effusion, I did place an order with all the upgrades. Victor should have the amp to me in 2 weeks or so and will post my findings. I will look into the KT88 and do have quite a few 6sn7 and 6f8g in my collection, have to get the adapter. 12AU7 is a new tube type for me, have to see what NOS options are out there that are reasonable.


----------



## Hifi Boy

You're welcome.
  
 This here is a very friendly community and you'll get help pretty quickly.
  
 Stop by whenever you feel like asking for advice.


----------



## svmusa

Few choices on NOS 12AU7, looking at preference on few that have good bass and overall clarity in the 8200.
RCA grey & black & top side getters, Sylvania black & grey, Raytheon black & grey, tungsol black & clear, Tungsten, Amprex non bugle boy, Brimar and Mullard.

In the new made version there is Northern electric as well.

Other suggestions are welcome as well.


----------



## Effusion

Well, there are actually quite a few NOS options you could try, including many of the variants of the 12au7 as well.
  
 I personally tend to prefer some of the variants myself, such as 5814 military types (CBS black plate and Westinghouse are some of my favorites).  The Mullards tend to be a bit thin in the low end and not as extended up top in my opinion, but I've had really good luck with the Brimar 13 series, such as the 13D5, which always gave me a little more weight down low.  Amperex, orange/green globes or Bugle Boys, are also quite nice and many really like them.  The Telefunken are also highly regarded by many, which to me are crystal clear up top, but a bit thin in the mid-range and low end for my general liking and can go for quite a bit of money nowadays.
  
 Below is a list of some of the 12au7 variants you may want to research:
  
http://www.vacuumtubes.com/12au7.html
  
 As far as cheap and easy to find options, RCA "clear tops" 12au7s are fairly easy to find and can be found very cheap if you search (I purchased several pairs for about $5 per pair).  They aren't the best 12au7 by far, but good for the money and while you try other pairs, etc.
  
 For the top end of this tube type, I really like the Amperex 7316s, but they are not cheap.  Also, if you are considering going with new production, the Psvane Mark II 12au7s are considered to be very good by many as well, but they are also not cheap (I have not tried them though).  The Tesla and Telefunken ECC802S are also quite nice and very clear/detailed.  I could keep going and going, but all of these are $100 pair or more usually.
  
 Check with @Dimu (fellow owner from this forum) if you are considering other non-12au7 types/equivalents.  Dimu has extensive experience with many other types, for which many considerations must be taken into account prior to trying them to make sure the voltages, etc. are safe for the amp.  Many require certain power tubes to be used exclusively, as using others will surpass voltage limits, etc. and could/will damage the amp.  I also think there are even more that can be used according to him, however a different transformer is required (most that are required won't fit into the case however).
  
 I hope this helps a bit, but let us all know.  Welcome to the club and keep us up to date on how the search/build goes!


----------



## Hifi Boy

Guys, my long awaited review has finally arrived, so please read it here so that I don't have to post the same thing twice! 

http://www.head-fi.org/t/806827/audio-over-ip-rednet-3-16-review-aes67-sets-a-new-standard-for-computer-audio/3045#post_13409313

I finally decided to give my system a review after I got the P5 Power Plant. I actually bought a new DAC recently as well, but didn't bother to write about it because the change was nothing remarkable. Don't get me wrong, my new, M2Tech Young DSD is good, but nothing breath taking.

What I would like to add here on the other hand is that the TU-8200 still scales remarkably well with all my updates! 

This could honestly be an end game amp for many people. There is really no need to update to another one after you got this one, unless you are prepared to give 10 times more than you'd give for Elekit.

One more thing I'd like to point out is that the power supply is a very and I do mean VERY important part of your system. If you can, please try and audition the P5. It has completely transformed my system.

In my opinion, the most important parts of a digital system are as follows: headphones, amp/tubes/power supply and then clocking. These things have impacted my system the most in the order of most important. Amp, tubes and power supply are all equally important.


----------



## Effusion

Very cool, I'm glad you are liking the P5!
  
 In many ways power is everything, for example, until the signal reaches the drivers, either speakers or headphones, the sound is in an electrical state traveling from end to end.  The electrical current from your outlet is thus the basis for the flow of current to your cans and its quality impacts everything else along the way.  Cleaner power will always give a better/blacker background and less noise between the notes, etc.  Basically the cleaner the power signal is the more impact and resolution is possible.
  
 I also agree about the Elekit, I'll be keeping the 8200 for years to come.  With so many features/abilities, in addition to the high caliber quality of its sound output, I personally don't have any desire to try anything else at the moment.  The big kicker is the price tag, which makes this a mid-budget amp for those wanting high-budget sound.  For some the only real downside is that it is a kit and not assembled, but there are ways to have others build it for you; even factoring in top dollar to have it built for you, you'll still be saving a ton of dough for what you get in the end.


----------



## Hifi Boy

Yes, I am now a believer in the importance of pure electric current. Before this, obviously like any other person I had my doubts but not anymore.

Anyway, what I think you might want to get is the TU-8500 to go along with your TU-8200. I was personally considering the same thing because I believe someone pointed out that it's a good product and adds more 2nd harmonic distortion and its actually cheaper than the TU-8200. I'm now not sure whether I should get one because my new DAC acts as a preamp as well.  

Also, please go through the thread that I posted my review in. There are certain cheap products which seem to be providing a lot of performance for the money they cost. I'm personally going to order a 10MHz clock that's built here in Japan to further improve my Mutec. The cheapest version is around $800 if I'm not mistaken, but I'm waiting for the top model to become available again which is double the price. Suffice it to say that the reviews of the cheapest model are all positive. 

To summarize for you what you could get from there:

Rednet D16R - Gets you off the USB (coming from PC) and onto Ethernet cable. (plug into Live Clock using AES).
CyberShaft 10MHz Clock - High precision external clock (should be used with Mutec or Live Clock with 50 Ohm BNC).
Antelope Audio Live Clock - Master clock which would be plugged into Mutec.
Mutec - end of this digital chain as you already know, plug into DAC.


----------



## sunneebear

Anyone know if these are any good?

http://www.ebay.com/itm/Elekit-TU-8200-Premium-Tube-Set-with-Genalex-Gold-Lion-/152438386773?hash=item237e093055:gugAAOSw4CFYpL1C

Thanks


----------



## Hifi Boy

The large ones are KT66 and are awesome. I have both, but prefer the smaller ones from PSvane.

You can go thru my posts and read about it in this thread.
In short, yes I recommend you get both.


----------



## sunneebear

hifi boy said:


> The large ones are KT66 and are awesome. I have both, but prefer the smaller ones from PSvane.
> 
> You can go thru my posts and read about it in this thread.
> In short, yes I recommend you get both.


 
  
 Thank you.  My present tubes must be getting old, I am getting a channel imbalance.  It is more noticeable in the 12AU7s than the KT88s.


----------



## Hifi Boy

I see, so you already have the KT88?

Well in that case, let me just tell you that you won't have as much bloom with KT66 as KT88.
I'm not saying that KT66 are worse, no far from it, but I'd say that at least Genalex KT88 add more bloom if that is what you're after. The KT66, might be then seen as a bit more "cleaner" sounding. I also think that KT88 have a wider soundstage.

On the other hand, if you try my current tubes, KR Audio KT88, then the best way to describe these is like a mix of KT88 and KT66 from Genalex. It actually removes some of the artificial bloom that KT88 has but leaves everything else intact.

I don't know what kind of sound you like, so it would be best to try them all out.


----------



## sunneebear

My current set is all psvane. Their KT88 sounds very clean, I don't think it has the bloom that you speak of. I will give these a try. 
Thanks.


----------



## Hifi Boy

Ok, I get it, you got an all PSvane setup.

Well in that case, I don't think you can go any better, at least not with these Genalex KT66.
I haven't actually heard the PSvane KT88, I just have the 12AU7, but I assume their KT88 would be better than either ones from Genalex.

Again, I'm not sure, but do get them and report back with your findings.

Glad I could help.


----------



## Hifi Boy

Guys, I was at this year's Spring Fujiya Avic Headphone Festival, and was told by the gentleman at the Elekit booth that they have a new 300B amp coming out!

Its going to be around 130,000 yen, which is around $1,120.
No, I have no idea whether its going to be a new headphone amp or just a speaker amp, but what I do know is that its supposed to come out this fall!

So yeah, we'll see what happens.

Now I'm torn between the new Luxman P-750u I heard at the show and this one, which I actually haven't even heard yet, but judging by how much I loved TU-8200, I imagine this one's gonna be nothing short of amazing.

Hey, Victor, can you get us some more info please?


----------



## vkung

Hifi Boy said:


> Guys, I was at this year's Spring Fujiya Avic Headphone Festival, and was told by the gentleman at the Elekit booth that they have a new 300B amp coming out!
> 
> Its going to be around 130,000 yen, which is around $1,120.
> No, I have no idea whether its going to be a new headphone amp or just a speaker amp, but what I do know is that its supposed to come out this fall!
> ...


Yes.. It is a new version of TU-8300R. It has speaker terminal and headphone Jacket.
I will demo this amp in LA Audio show.


----------



## Hifi Boy (May 20, 2017)

Very nice.

Let us know how it sounds compared to TU-8200 when you get it!

Well, I was sniffing around a bit and judging by the reviews of the old version, it's the same story like with TU-8200. People are just astounded by how good it sounds for such a low price. You can read more about it here.

http://wallofsound.ca/audioreviews/...8300r-is-this-the-worlds-best-1000-amplifier/

I guess we are in for a treat!


----------



## vkung

http://wallofsound.ca/audioreviews/...8300r-is-this-the-worlds-best-1000-amplifier/

I guess we are in for a treat! [/QUOTE]
I sold TU-8300 in 2010.  I knew this amp quite well.  
The new 300B amp has a lot more improvements from its predecessor (TU-8300R).


----------



## Andrew Rieger

vkung said:


> http://wallofsound.ca/audioreviews/...8300r-is-this-the-worlds-best-1000-amplifier/
> 
> I guess we are in for a treat!


I sold TU-8300 in 2010.  I knew this amp quite well. 
The new 300B amp has a lot more improvements from its predecessor (TU-8300R).[/QUOTE]

Hey Victor, do you think this will be a better headphone amp than the 8200DX?


----------



## Hifi Boy

For double the price, it damn well be!


----------



## Hifi Boy

Someone pls delete this.


----------



## vkung

Andrew Rieger said:


> I sold TU-8300 in 2010.  I knew this amp quite well.
> The new 300B amp has a lot more improvements from its predecessor (TU-8300R).



Hey Victor, do you think this will be a better headphone amp than the 8200DX?


----------



## vkung (May 25, 2017)

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----------



## vkung (May 25, 2017)

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----------



## vkung

They are different
The Tube set : 12AU7 X 2 + !2aX7 + 300B x 2
Also you can upgrade the OPT


----------



## vkung

Hifi Boy said:


> For double the price, it damn well be!


6L6GC is $20 each
300B is 5 times more..
Also the OPT and  power Transformer are  double the size and weight..


----------



## Hifi Boy

Wow, must say it looks really nice.


----------



## Dimu

I like the look of this new amp very much. Looks like there is room for pot upgrade too.

In other news- looks like NOS tube supply is getting much tighter. Compared to a year ago availability of good stuff is much diminished.


----------



## Dimu

Finally got time to work on fitting the large power transformer so that case can be closed. Also decided to move away from case cooling for mosfets and added passive air cooling instead.


----------



## Dimu

For the first time I can use big tubes with the amp case closed. TT21 beats Cossor 807 for sure- no contest! Of course both driven by E80CC. Sweet!!!


----------



## Dimu

sunneebear said:


> Hello everyone, My name is sunnee and it's been 26 hrs since I rolled my last tube.



What sunnee said 

Swapped GEC TT-21 for GE 6550. Then 26 hours later played with Mullard EL34 and Telefunken EL12 spez and left EL12 in the amp for now. Very enjoyable sound. Tubes were made in Berlin in 1960. Wondering when I get bored and start rolling again


----------



## Dimu

Swapped my Dutch E80CC for Siemens E80CC. These tubes are weird- they clearly say Made in Germany and carry Bundeswehr falcon logo together with delta code indicating Dutch origin. Military boxes indicate 1974 as the year they were packaged. Don't hear any difference with Dutch E80CC and test parameters are very consistent between these Siemens tubes and all other E80CC I have tested. I still believe E80CC is the main improvement that can be made to this amp- they drive all output tubes beautifully.


----------



## sunneebear

@Dimu 
I swore off rolling because it was draining my wallet and I've learn to sit back and enjoy what I have.  I do not appreciate you shoving your tube rolling pics in my face.  
Actually I pretty easy.  I even find the stocks enjoyable.


----------



## Dimu

sunneebear said:


> @Dimu
> I swore off rolling because it was draining my wallet and I've learn to sit back and enjoy what I have.  I do not appreciate you shoving your tube rolling pics in my face.
> Actually I pretty easy.  I even find the stocks enjoyable.



I have stayed with Telefunken EL12 spez and Siemens E80CC since the last time I rolled them... Very musical and enjoyable, especially if volume is turned up. 

Sadly I don't think I'll be doing much shopping for this amp- the market for interesting tubes has dried up. EL12 spez and E80CC are rare now and are up in price, usual GEC tubes are nowhere to be found. I wanted to try Tung Sol 6550 but I only found it for $700 a pair. I was thinking about trying EL156 but it has weak grid voltage rating like WE 350B- won't be sustainable in this amp. I am now thinking of building another amp with directly heated triodes. So instead of rolling tubes in one amp I can compare two amps to each other 

Basically once I got the big power transformer into the case and improved mosfet cooling I don't want to touch the amp any more- it is just perfect. By the way with EL12 spez it runs much cooler than with TT-21 or 6550.


----------



## vkung (Jul 24, 2017)

*Why Mr. Fujita uses 12Au7 X 2 and 12AX7 X1 instead of 12AT7x 2 in TU-8600
1. To achieve higher stability of NFB, the overall NFB amount is decreased, and instead, cathode feedback is applied to 300B.
(This is why the third winding for cathode NFB is added to the OPT.)

2. Applying cathode NFB requires bigger driving amplitude for 300B.

3. To achieve such large driving amplitude, 12AU7 is more suitable than 12AT7, as its max. rating is higher than 12AU7.

4. Since the gain of 12AU7 is smaller than that of 12AT7, 12AX7 is used for the first stage.

Mr. Fujita conducted the circuit simulation to make sure his theory is correct, and confirmed that bigger amplitude can be achieved when 12AX7x1+12AU7x2 than 2x12AT7.
(The driving ability of 12AX7x1+12AU7x2 with TU-8600 circuit is 200V peak-peak without wave clipping)
For the headphone section, he uses 3 resistors tapped to the OPT.  This made TU-8600 is a very good headphone amp.. 

*


----------



## Hifi Boy (Jul 9, 2017)

I've been checking out some tubes for the new Elekit amp and it seems to me that these could be really good.

https://www.takatsuki-denki.co.jp/products/ta-300b.html

The price is double the KR Audio 300B, at least here in Japan!
Yet these are domestic tubes, while KR Audio is an import, incredible to say the least.

Also, I've recently auditioned the above mentioned Luxman p-750u and decided not to buy it. The sound was powerful, but on closer listen, it was just too cold for my tastes. I've also heard Fostex HP-V8, which btw uses 300B and KT88 tubes, but wasn't impressed either. Sounded flat and uninvolving to me.

Can't wait to hear the new Elekit. I'm almost 100% sure it's going to be amazing!


----------



## Harry_Y

Hello all, I just ordered a TU-8200 DX today, and read through the thread.

This will be going into my Home Office/Den so I would tend to believe it should work well for my use.

One of the things that did concern me a little prior to buying the amp is having parts that become unobtainable.
So it may be wise it get a few spares of the FETs and IC's in case they become obsolete and hard to find.

The ALPS Blue pot looks interesting (I'll need to find a source for that one).

Is there anything I should watch out for during the build?

Thank you


----------



## Hifi Boy

Hi Harry, welcome to the forum!

I'm no DIY expert and had my amp ordered already built, so I can't help you with that, but I wonder why you couldn't wait a bit longer for TU-8600 to come out and get it instead?


----------



## Harry_Y

Hifi Boy said:


> Hi Harry, welcome to the forum!
> 
> I'm no DIY expert and had my amp ordered already built, so I can't help you with that, but I wonder why you couldn't wait a bit longer for TU-8600 to come out and get it instead?



I considered the 8600 but the 8200 will do what I need (audio for my Home Office/Den)

Plus the 8200

Is available today
Has the same output power (8 watts)
Is smaller in size (I want the amp on my desk so I can easily reach the volume knob, and my desk is already loaded with monitors etc)
Is a little less money (more money left over for playing with tubes)
Has Two Inputs (I did not want to buy a preamp or need to build a switch box)
Has an internal DAC available (Probably not the best quality but should work enough to run my PC through it if desired)

I've never dealt with Elekit, nor have I seen their products in person so this is a way for me to buy
in with a smaller investment and If I truly love their products... well there's always the living room.


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## Hifi Boy

Yeah, now that you listed all those readings, I have to say it makes sense! 

What I can tell you, on the other hand, is that you won't regret ordering an Elekit product and certainly not from Victor. I ordered my Mundorf capacitors from him as well. Everything went very smoothly.

The TU-8200 is a one of a kind amp which sounds just amazing for its price point. I highly doubt you will get a better deal anywhere else for that money. Let us know what you think when the amp arrives!


----------



## Hifi Boy

vkung said:


> *Why Mr. Fujita uses 12Au7 X 2 and 12AX7 X1 instead of 12AT7x 2 in TU-8600
> 1. To achieve higher stability of NFB, the overall NFB amount is decreased, and instead, cathode feedback is applied to 300B.
> (This is why the third winding for cathode NFB is added to the OPT.)
> 
> ...


Hey Victor.

Seeing as how the Wall of Sound guys still haven't published the review of TU-8600, can you let us know how does the new amp compare with TU-8200?

With and without the upgrades of course!


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## vkung (Aug 23, 2017)

TU-8600 is a 300B amp. The sound of 300B is different from 6L6 tube.
TU-8600 has a third winding (CFB to reduce the Negative Feedback..

*(output transformer with cathode feedback CFB winding)*
To make the most of the 300B tubes, the characteristics of the various parts and circuits including the OPT have been improved. NFB is applied to the cathode of the 300B by the third winding of the output transformer as well as to the voltage of the amplifying stage. Overall NFB is minimized as well as the chance for transient response.

*Why CFB is important* - Cathode Feedback minimizes THD and intermodulation distortions and makes total bandwidth ultra-wide without using overall negative feedback from output to input of your amp. All of it makes sound amazing, detailed and spacious..

you can use Lundahl LL2770 (custom made for TU-8600)


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## Hifi Boy

How much wider would you say the soundstage is compared to TU-8200?
What about the detail, sweetness and warmth of the sound?

I'm using KT-88 with my TU-8200, so how would you compare a TU-8200 with KT-88 and TU-8600 with 300B?


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## vkung

IT is quite different in sound .. TU-8600 with Lundahl is double the price of TU-8200. Also 300B is 3 times more than KT88.
Indeed, TU-8600 is very musical.. It is my personal preference.


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## Hifi Boy

Quite musical you say. That's good, I love warm, smooth and musical amps.
Unfortunately, I'll have to wait till November to hear it at this year's Fujiya-Avic show.

The thing is, I'm looking for an endgame amp and the TU-8200 value for money is beyond any amp I've ever heard, which is why I'm considering TU-8600 now.
As I've mentioned earlier, after auditioning the Luxman p-750u earlier, its now off the table because its too cold and uninvolving, I prefer my TU-8200 (87K yen assembled) to this 320K yen amp.  

The other 2 amps I'm thinking about are Goldmund Telos HDA (9625 CHF) and Viva Egoista 2A3 (€7250).

Yes, they are *way* more expensive than even maxed out TU-8600 with all the upgrades you offer, but honestly, I would not be surprised if, when maxed out with all the upgrades and fitted with above mentioned Takatsuki 300B, this amp could probably match their sound. I'm actually only basing this on my experience with my TU-8200 and actually having heard Goldmund Telos HDA. Haven't yet heard the Egoista, but people say its the smoothest and sweetest sounding amp out there.

I'll have the opportunity to compare Goldmund again with TU-8600 at the Fujiya-Avic show this November, and then I'll make my decision. 
I will certainly post my impressions when comparing the TU-8600 and the Goldmund. Then, people will have an idea how close/far they actually are with this Elekit set from what is currently considered the best all-in-one DAC/AMP out there.


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## vkung

The sound from solid state and Tube amp is quite different. AMtrans in Tokyo will offer upgrade version of TU-8600.


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## Hifi Boy

I remember I went there when I bought Mundorfs from you, because you recommended this shop to me, haha!

Yes, they did a good job of installing them into my Elekit, but I'm not sure whether they will have the Lundhals as well.

I'll try contacting them to see whether I can come for a listen before the Fujiya-Avic in November.

Thanks for reminding me about them Victor!


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## vkung

Yes Amtrans will carry Lundahl LL2770


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## Hifi Boy

Wow. Sounds too good to be true! 

BTW, Wall of Sound review is still not up, after more than a month now...


----------



## vkung

Hifi Boy said:


> Wow. Sounds too good to be true!
> 
> BTW, Wall of Sound review is still not up, after more than a month now...


any time Noam is writing it now..


----------



## lucidreamer

Does anyone know if I can use 6085 tubes with my stock Elekit 8200 amplifier without any problems? I am currently sticking to my RTF 12AU7 pre-amp tubes and find them the best so far with TFN ribbed plates on the way to try. But I am thinking of purchasing the 6085 tubes to try in my amp because there are great reviews about those industrial versions of '12AU7' and they are supposed to be interchangeable with higher driver loads. Thanks.


----------



## Hifi Boy

Hi lucidreamer.

I personally can't say, but I have googled the tubes you described and I do remember that someone here recently posted some pictures of his TU-8200 with these tall input tubes you mentioned. I'm using 12AU7 so I immediately noticed that the type is different because yours are much taller.

I'm sure Victor will be able to give you a better answer.
If not, you should try to contact the very helpful Tamura-san from Elekit.


----------



## lucidreamer

Thanks Hifi Boy. I ordered a pair of Philips E80CC tubes from the seller in Belgium and it may take a couple of weeks to arrive. I am also considering getting a pair of Tungsram E80CC which should provide a different sound signature compared to Dutch tubes.
I am 99% positive that it will work just fine in this amplifier without making any modifications which are suggested by other forum members. I double-checked the schematics again and the stock rectifying bridge circuit consists of DB107 diodes which are rated at 1A of current, therefore, it should suffice to drive the E80CC heaters at 600mA. The worst-case scenario is that there will be not enough current to drive the power tubes and it may need a transformer upgrade which is unlikely, this amplifier has the reserve. 
I did an extensive online search on that subject and there are no cases of someone blowing up their amps by switching to E80CC tubes. Only a couple of people stated those tubes sounded very quiet in their setups, but each amplifier is different, some Chinese ones use small cheap parts that are on the edge and have no reserve.


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## Hifi Boy

Sounds good to me, please let us know your opinion once they arrive.

The only thing I can add to this is that me personally, I've never noticed any difference while changing input tubes.
Now, I'm not saying that there is no change, or that you won't notice anything I'm just telling you what my experience was.


----------



## lucidreamer

There is a significant variance between different preamp tubes in terms of their sound character, transparency and dynamics. I can hardly hear much difference when listening through speakers but with the headphones it is a different story.

I just got a pair of nice GE 5 star 5814WA and those are so sweet.


----------



## Effusion

Harry_Y, welcome to the club!

The TU-8200 is a great amp for desktop use and this is where I actually use mine.  You are right about it being small enough, yet powerful enough, and with more than enough features to keep you satisfied.  I do not know much about the new 8600 yet and have never heard it, however besides what you have already noted, since the 8600 uses 300B tubes, unless you are crazy about this tube type, which are quite amazing, it doesn't make much sense for desktop use, compared to full/main setup use.  The 300B tubes can go for crazy amounts of money, with true WE NOS being almost impossible to find, at least at an 'okay' price.  There are other options for the 300B out there for sure, but I've heard from those that love this tube type, that quality can vary, especially with some of the newer production.  I've also heard that the 300B tubes can also get very hot, which may not be ideal for desktop use, depending on your situation.  Now with that all said, the 300B tube is probably considered one of the best, if not the best, tube type for audio use in general and it has been highly praised for many years.  I believe Elekit also has experience using this type in their other designs, so I'm sure the 8600, with nice 300B tubes, would beat the 8200 sonically.  However, the question is, by how much and if it is worth it for you and in your system in the long run.  Going off what you have stated, I think you made the right choice, plus in the future you can always try the 8600 if you want to, plus now knowing that you have given the 8200 a chance.

As an additional note, some of the power tube types for the 8200 also get very hot.  In my experience these are generally the KT-88, KT-66, and 6550 in particular.  If you are concerned about heat build-up in the case, which I was, and also which can lead to additional component ware over time, you might want to consider a passive cooling system to help dissipate it.  Several users here, including myself, have implemented solutions that can help with this.  If you prefer to not make any holes in the case, which may let RFI/EMI in, one option is to use tube socket savers on the power tubes, in order to lift them off the hood of the case a bit, thus creating less heat transfer from the tube to the metal case and thus eventually inside the case.  Just be aware that most socket savers are for tube testers and not for HiFi applications, so choose wisely and let me know if you want some recommendations.

Let us know how everything goes and what questions you may have during your new journey with this amp.

Lucidreamer, I agree with you that the input tubes do change/alter several characteristics of the sound, such as signature and tone, and can really bring out the best in the amp.  However, I also have to say that I've generally found that the differences are slight in comparison to what can be done with the power tubes, similar to HiFi Boy's experience.  However, we must remember that in stock mode, there are many more easily available and different types of power tubes that can be rolled than within the direct 12au7 input tube family.  In my experience, going from a KT-88/66 to a 6L6GC and then to an EL-34, gives quite a bit of difference compared to different brands/designs within the input/signal tube 12au7 family.  However, as I believe you are experiencing with the 5814WA tubes, switching out of the direct 12au7 tube family will yield much more noticeable differences, often times better as well, and there are several types that I recommend.  In particular, the Brimar 13 series, the Amperex 7316 (my personal favorite), as well as the Tesla and Telefunken ECC802S, all in addition to the 5814s, have given me much better sound, to my ears, than most 12au7s.  As far as the 5814 family goes, my personal favorites are the CBS black plate and Westinghouse types; I have tried GE black plates and found it to be a bit stiff and emotionless compared to others, however they were not the 5 star.  In general and across many different types of NOS tube families, I've found that the militarized versions generally will give tighter, more dynamic sound, with better highs and tighter bass, if not just a bit less sweetness and air overall than non-military types.  To me they generally sound more solid state, which can be a good or bad thing based on the rest of the system and your preferences.

From my personal experience, the best advice I could give to anyone looking to do more rolling with this amp is to first zero in on which power tube types you prefer overall and then tweak the sound by trying various input tubes (from different families as well) with them.  Also, a great resource is fellow owner and member Dimu, who has done extensive rolling in this amp, well outside the standard 6L6GC/12au7 family and with great reported results.

Happy listening all!


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## Hifi Boy

Hey @Effusion, haven't seen you in a while. 
Are you planning on getting the new TU-8600?

@lucidreamer, its great that you can hear these differences, I can't.

Let me just tell you what made most difference to me:

Electroharmonix 6L6GC to Genalex KT66 - Big Difference
Genalex KT66 to Genalex KT88 - Noticeable Difference
Genalex KT88 to KR Audio KT88 - Somewhat Smoother Presentation, no artificial bass bloom, nothing more

As for the input tubes, whether stock or Genalex 12AU7 or Psvane 12AU7, I did not notice anything.
Maybe I could try stock VS Psvane again, but I doubt I would notice much.


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## lucidreamer (Sep 6, 2017)

I just got a package from Belgium today with a pair of Philips SQ E80CC/6085 tubes that I bought from eBay last week at a reasonable price. This is indeed a different animal in this amplifier and this Heerlen-made tube from Holland sounds like the best 12au7 on steroids. The sound is very clean, dynamic and transparent yet still tube-like and not solid state but rich and pleasant. The first impression I immediately got was the sound became 'quicker' and not as laid-back or lazier as before with the GE 5-star ones, still the 5-star ones are best overall for me.
6085 are really interesting tubes to compare against the 12au7 types. The volume is a bit louder too because they have a higher gain which is not a big deal. I have an impression that they are so revealing that perfectly-recorded tracks sound better with them but poor quality ones sound even worse. The instrument separation is noticeably better and the music has become slightly more 3-d.
I am still a bit nervous to keep the amplifier running them for longer periods of time because they demand twice more current, however, after about an hour, the sound is still the same, no smoke or other malfunction symptoms  detected from the amplifier which is a good start. I hope this amplifier will have the reserve to run them (fingers crossed).
I have settled on the Mullard EL34 X2F for power tubes and those are taming the highs a little bit. With other power types, like KT88 or military grade ones it would probably result in a fatiguing experience at the end of the day. Even matched with the EL34s - it may be a bit overwhelming for some types of music to listen to for a longer time, I am afraid.
Now waiting for a pair of Tungsram E80CCs to arrive from Ukraine to compare with Philips.


----------



## Allegroz

lucidreamer said:


> I just got a package from Belgium today with a pair of Philips SQ E80CC/6085 tubes that I bought from eBay last week at a reasonable price. This is indeed a different animal in this amplifier and this Heerlen-made tube from Holland sounds like the best 12au7 on steroids. The sound is very clean, dynamic and transparent yet still tube-like and not solid state but rich and pleasant. The first impression I immediately got was the sound became 'quicker' and not as laid-back or lazier as before with the GE 5-star ones, still the 5-star ones are best overall for me.
> 6085 are really interesting tubes to compare against the 12au7 types. The volume is a bit louder too because they have a higher gain which is not a big deal. I have an impression that they are so revealing that perfectly-recorded tracks sound better with them but poor quality ones sound even worse. The instrument separation is noticeably better and the music has become slightly more 3-d.
> I am still a bit nervous to keep the amplifier running them for longer periods of time because they demand twice more current, however, after about an hour, the sound is still the same, no smoke or other malfunction symptoms  detected from the amplifier which is a good start. I hope this amplifier will have the reserve to run them (fingers crossed).
> I have settled on the Mullard EL34 X2F for power tubes and those are taming the highs a little bit. With other power types, like KT88 or military grade ones it would probably result in a fatiguing experience at the end of the day. Even matched with the EL34s - it may be a bit overwhelming for some types of music to listen to for a longer time, I am afraid.
> Now waiting for a pair of Tungsram E80CCs to arrive from Ukraine to compare with Philips.



Is it safe to use e80cc + el34 witch stock transformer and stock part?.. or I must upgrade some part to use that tube..


----------



## lucidreamer

I am running E80CC with stock parts (actually a DX version with upgraded capacitors, resistors, etc.). So far it is ok but only time will tell. Like I mentioned earlier the stock DB107 diodes are rated at 1A and should be fine to drive these tubes. The power transformer is also pretty beefy and is 250va. An extra 2w of load should not do anything to it, there are tons of posts on this site where people run those tubes with smaller amps and did not blow them.
But to be extra safe - you can upgrade the DB107 diodes to something like 2A and also upgrade the power transformer to a bigger one that can fit in the case which would be a challenge and a significant expense. I would not bother doing that if it were me.


----------



## Dimu

Harry_Y said:


> Hello all, I just ordered a TU-8200 DX today, and read through the thread.



It is a very, very good amplifier. At least mine is, but I put the best components I could find into it from the very beginning. Resistors, caps, TDK pot, etc.



Harry_Y said:


> Is there anything I should watch out for during the build?
> Thank you



Get a bigger rectifier for preamp heater supply so that you can run E80CC with smaller power tubes. Then get a pair of Dutch E80CC. Unfortunately this is where meaningful tube upgrades end because you can only mix E80CC with 6L6GC or 807 tubes using stock power transformer. Still, upgraded rectifier with E80CC and good 6L6GC or 807 is the best sound you can get out of stock transformer- much preferable than 12AU7 with any power tubes (I tried pretty much everything worth trying other than TungSol 6550). I would recommend Cossor 807, RCA 6L6GC black plate or GE 6L6GC. Sylvania is ok too. E80CC has twice the plate size of 12AU7 and consumes twice the heater current and that does make a difference.

I've been listening to E80CC and Cossor 807 from 1950s before I swapped out power transformer to a bigger version. I could hear difference with the bigger transformer right away (I swapped transformer for more heater current, but I guess bigger core influenced signal power as well), but more importantly it allowed me to install power tubes with bigger heaters while retaining E80CC. After some experimenting I ended up using for months Telefunken EL12 spez made in 1960. Today I swapped 807 back in and it is clearly lacking, at least to my taste. Put GEC TT21 in there- better than 807 but still lacking compared to EL12 spez (TT21 is GEC KT88 with top anode for higher voltages). Then swapped in GE 6550- similar sound to TT21. Next came Mullard EL34 XF2- this was closest to EL12 spez sound of all the tubes I tried today. So I gave up an popped EL12 spez back in- feels like home again.  Another bonus with EL12 spez is that amp runs very cool- huge difference relative to bigger tubes. Those Mundorf caps will sure be more comfortable than with bigger tubes that overheat the amp.


----------



## Dimu

Allegroz said:


> Is it safe to use e80cc + el34 witch stock transformer and stock part?.. or I must upgrade some part to use that tube..



If you do that you will overload preamp heater rectifier and you will overload the power transformer. Rectifier might give you unpleasantly smelling smoke at some point, but transformer overload consequences could be more interesting. The question is whether amp's 3A fuse will stop really bad things from happening after transformer coils fail due to extended over current operation. 

Upgrading rectifier is trivial and costs just couple or three dollars. Upgrading power transformer is a project. So you have two easy choices:
- EL34 with 12AU7
- 6L6GC with E80CC and upgraded rectifier

I would go with the second option.


----------



## Dimu

lucidreamer said:


> I am running E80CC with stock parts (actually a DX version with upgraded capacitors, resistors, etc.). So far it is ok but only time will tell. Like I mentioned earlier the stock DB107 diodes are rated at 1A and should be fine to drive these tubes.



Please don't confuse people with conclusions based on bad math- not when it comes to safety. E80CC is rated at 0.6A current. That is nominal rating, actual current draw can be higher than that. And you have 2 tubes. So you are definitely looking at more current than what those rectifiers are rated for. DB107 has maximum sustained current rating of 1A at 25C ambient  temperature. Temperatures inside that amp go much much higher than that, especially if you use big power tubes. So you are over temperature and over current, both by unhealthy margins. How does that qualify as "should be fine"?



lucidreamer said:


> The power transformer is also pretty beefy and is 250va. An extra 2w of load should not do anything to it, there are tons of posts on this site where people run those tubes with smaller amps and did not blow them.



What do you mean "pretty beefy and is 250va"? How is that going to compensate the fact that having 1.2A rectified plus 3A RMS current far exceeds the 6V secondary rating of 4A? Elekit recommendation is to allow for twice the current on transformer end relative to what rectified current is for the heaters. Also for your information, a properly designed transformer to accommodate those extra heater amps requires "beefier" core than the stock transformer.

And where do you get 2W? Power leaving that transformer coil is much more than 2W over rated power if you use E80CC and EL34 together.



lucidreamer said:


> But to be extra safe - you can upgrade the DB107 diodes to something like 2A and also upgrade the power transformer to a bigger one that can fit in the case which would be a challenge and a significant expense. I would not bother doing that if it were me.



When you say "extra safe" you are implying that if you don't do those things you are "reasonably safe". This is obviously wrong- bad conclusions based on bad math.


----------



## Allegroz

Thanks to Dimu..
Upgraded D7 to 2A...
Ordered E80CC philips and 6L6GC GE. Stunning beautiful..


----------



## lucidreamer (Sep 11, 2017)

I wrote to Elekit representative in Japan regarding the overall application of the E80CC preamp tubes with this amplifier and got the response on the following day - see attached.


----------



## Dimu

lucidreamer said:


>



Yes, do not use E80CC in stock amp to avoid any trouble. Upgrading heater rectifier and watching 6V transformer secondary budget makes it as safe to use as 12AU7. Upgrading power transformer to increase 6V secondary current rating allows combining E80CC with any power tube supported by the amp (which again is not a simple question as you have to watch out for multiple parameters including importantly grid voltage). 

As for oscillation- my amp does not have any as per oscilloscope and spectrum analyzer tests I did earlier. Since oscillations depend on many factors including capacitances throughout the circuit your results may vary in theory. You can stick a basic analog oscilloscope at the amp output to see if you have oscillations (but do it in parallel to the usual load, do not replace speakers with oscilloscope as this is not good for the amp). I mostly tested with 1KHz signal. I am not too worried about oscillation with reasonable tube substitution as the amp has global NFB. I also use 12AT7 instead of 12AU7 in my TU-8500 preamp and thanks to heavy NFB there is no difference there. 12AT7 has much higher gain than E80CC which in turn has higher gain than 12AU7.

Once you have have proper heater power budget for the tubes the next important factor is heat dissipation. The amp gets very hot inside with bigger tubes. This is not good for all of the components inside, caps in particular. There were many posts on both passive and active cooling in this thread. I experimented with moving mosfets to the back of the amp case but mains noise pickup was difficult to deal with (but not impossible). I even tested configurations with paralleled mosfets for the power tubes where one mosfet remained on the board and another one was located at the back wall of the amp. After all that I ended up sticking small radiators on all four mosfets and opening up passive airflow by drilling small holes at the bottom and in the top cover over those mosfet radiators. Combined with EL12 spez my amp runs very cool now for many hours. External temperatures are at least 20C lower than if I used something like KT88 and internally the difference is even more significant.


----------



## Dimu

Allegroz said:


> Thanks to Dimu..
> Upgraded D7 to 2A...
> Ordered E80CC philips and 6L6GC GE. Stunning beautiful..



That indeed is beautiful, enjoy! As far as look GE 6550 is one of the more stunning looking tubes in that amp.

I've been trying to find NOS 211 tubes after seeing Sunvalley kit at Victor's. The pictures don't really do it justice, those tubes are very impressive in person. See Sunvalley amp on http://www.vkmusic.ca/.


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## lucidreamer (Sep 11, 2017)

Allegroz said:


> Thanks to Dimu..
> Upgraded D7 to 2A...
> Ordered E80CC philips and 6L6GC GE. Stunning beautiful..



Allegroz - could you tell us which source and part # you used for 2A replacement for D7 diode (DB107)? I may upgrade it too in the future if time permits. Even if the D7 fails because of the extra current draw (which I still think unlikely) it is a 10c replacement part anyways. Yes, it is rated for 1A but has a peak current of 50A per datasheet. Been running E80CC tubes with EL34 and now GE 6L6GC 8 hours per day for more than a week already without a hiccup. No changes in sound, volume, temperature or a funny smell emanating from the amp as suggested in the other post. I really like how the Philips E80CC pre-amp tubes sound combined with NOS GE6L6GC power tubes. They produce a pretty mellifluous non-fatiguing tone with lots of transparency and details yet smooth and sweet, I can listen to this setup for hours without a break. 

Would definitely like to try RCA with them some day I can find a good deal. I almost snatched a pair of interesting RCA 6L6GC blackplates on eBay last night for a good price. Likely a NOS/ANOS but someone grabbed them when my browser session expired on the phone because we lost our internet during the hurricane in Tampa last night. Too sad.

Another thing I am trying to understand in the schematic on Page 19 - the secondary winding from the stock transformer that feeds the power for heater tubes has 6V and 4A output that goes right into D7 rated at 1A. Why not use at least 4A-rated rectifiers instead of 1A here without having to rely on a particular tube type, etc.?

Thanks.


----------



## Allegroz

lucidreamer said:


> Allegroz - could you tell us which source and part # you used for 2A replacement for D7 diode (DB107)? I may upgrade it too in the future if time permits. Even if the D7 fails because of the extra current draw (which I still think unlikely) it is a 10c replacement part anyways. Yes, it is rated for 1A but has a peak current of 50A per datasheet. Been running E80CC tubes with EL34 and now GE 6L6GC 8 hours per day for more than a week already without a hiccup. No changes in sound, volume, temperature or a funny smell emanating from the amp as suggested in the other post. I really like how the Philips E80CC pre-amp tubes sound combined with NOS GE6L6GC power tubes. They produce a pretty mellifluous non-fatiguing tone with lots of transparency and details yet smooth and sweet, I can listen to this setup for hours without a break.
> 
> Would definitely like to try RCA with them some day I can find a good deal. I almost snatched a pair of interesting RCA 6L6GC blackplates on eBay last night for a good price. Likely a NOS/ANOS but someone grabbed them when my browser session expired on the phone because we lost our internet during the hurricane in Tampa last night. Too sad.
> 
> ...


The default for D7 is db107 1A rated... I upgraded it to DB207 2A rated...

Transformers rated 6v n 4a...
It divided for two, first preamp tube via diode because it feed dc volt.. second powertube without diode, ac volt... total current powertube + preamptube must be 4a..
It will be wasting if we used 4a diode in D7.. because preamp tube only used 300+300 12au7 : total 600ma or 600+600 e80cc : total 1200ma..


----------



## lucidreamer

Makes sense, thanks Allegroz. Just noticed that you also opted for the GE 6L6GC plus E80CC. Those GE NOS power tubes are great ones, I like them a lot too! I compared them to the modern TAD 6L6GC today and the GE are much cleaner and more transparent sounding with great dynamics.


----------



## lucidreamer

I ordered a min batch of 20 DB207 bridge rectifier replacement for D7 from China through eBay for $4 shipping incl. 
Unfortunately I could not find it anywhere to buy online within the US. It may take a couple of weeks or more to get from China. Once received, I will swap the 1A D7 for the 2A which will be like a 10 min job. No removal of the top PCB even needed, only a desoldering gun to remove the part.
If someone has a spare DB207 or two to sell from the US, please PM me asap.

Thanks.


----------



## Dimu

lucidreamer said:


> I ordered a min batch of 20 DB207 bridge rectifier replacement for D7 from China through eBay for $4 shipping incl.
> Unfortunately I could not find it anywhere to buy online within the US. It may take a couple of weeks or more to get from China. Once received, I will swap the 1A D7 for the 2A which will be like a 10 min job. No removal of the top PCB even needed, only a desoldering gun to remove the part.
> If someone has a spare DB207 or two to sell from the US, please PM me asap.
> 
> Thanks.



There are many distributors of electronic parts such as Mouser and DigiKey for example. They have huge warehouses with many parts on hand and can ship them overnight. When I order stuff from those distributors I usually look at what else I would need. You can get better bypass caps for example from the same source.

There is also no reason to use specifically DB207, any rectifier with suitable physical footprint will do. Mine is 3A rated but I had to mount it creatively because pins are arranged differently. Voltage is not important in this case as voltage is nominally about 8.5V in this case. Temperature ratings are more important for this application.

When desoldering I use regular braid and lift iron temperature a bit, still being careful not to burn the tracks off the PCB. Combined with lots of good flux this sucks all solder clean from the vias, assuming you used proper solder when assembling the amp initially. I use heat gun for SMD soldering only and even then to basically reflow the components after initial soldering with micro iron.


----------



## vkung

*Here is TU-8600 review from wall of sound.*

*http://wallofsound.ca/audioreviews/amplification/review-elekit-tu8600-single-ended-300b-amp-part-1/*


----------



## Hifi Boy

I believe that the most important thing to conclude from the review is that this is the best sounding 300B amp that Noam had the pleasure of listening to (for long enough time).

I can't wait to hear it for myself, unfortunately Amtrans still hasn't got anything up on their website, so I'm assuming it's not available yet. As for the Elekit web shop, it should start selling on the 19th I believe.


----------



## Hifi Boy

All this talk about input tubes got me wondering.

Can anyone tell me whether these large E80CC input tubes will be safe to use with TU-8600?


----------



## Harry_Y

Thanks all, the amp has been up and running fine, I wound up with kt88 tubes.
It's  more than loud enough to make my ears hurt with speakers so plenty of power for my use.

I'm not worried about the heat as I have other tube gear  (amateur radio tranceivers)
That run much hotter than the Elekit does..


----------



## lucidreamer

The package with DB207 bridge rectifiers should arrive today from China, it only took around a week which is not bad at all. I may postpone replacing the stock rectifier until later and do more more upgrades to my amp altogether. 

I am now considering replacing the AMTRANS AMCO C7, C8, C9, C10 caps with Mundorf Supreme Evo ones ordered from Victor based on the positive reviews on this great forum.

Pretty happy with my AMTRANS capacitors already, they sound very pleasing and musically with plenty of details. Just wondering if the Mundorf Supreme Evo are really worth the extra expense and provide tangible improvement to the sound. Or they are similar to some interconnects upgrade - after a specific point all the expensive audio cables fall into the common moot point area. For instance, honestly, I am having hard time telling the difference between my  $2k Nordost Moon Glo Quattro Fil audio interconnects and the DIY solid-silver wires, both sound the same to me. 

I would not mind trying the Mundorf caps if they help increase the resolution and lift some veil from the audio to make it sound a tiny bit cleaner maybe. Please advise.

Thanks.


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## lucidreamer (Sep 22, 2017)

I did some considerate research on the coupling caps for the last couple of days and decided to order the Mundorf MCap SUPREME EVO Silver/Gold caps to upgrade the existing AMTRANS ones. The Mundorf seem to be great capacitors and lots of people noticed subtle yet tangible improvements in the detail and overall sound. They however have a little bit of coloring to the high notes and are not neutral but I would not mind that.

Could someone please confirm if this is the right installation regarding the inner and outer foil (ground) polarity for those caps as posted by Dimu earlier in this forum? It appears to be correct to me and the ground (outer foil) must be soldered to the lower impedance or input of the signal and the inner foil goes to the output. The bottom left (C4) is upside down to mirror the C3 on the right, because the PCB layout is symmetrical which makes sense to solder them that way.


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## lucidreamer

I found my own answer how to replace the Mundorf capacitor using the correct polarity for Elekit in regards to the 12AU7 tube on the schematics for TU-8200.

Here is the solution (if someone is interested) - based on several sources online the outer foil (shorter lead of Mundorf) always needs to be soldered to the plate the pre-amp tube that has the lowest impedance.

This is Pin 1 and 6 for the 12AU7 tube on the schematics and both capacitors (two per channel) are already connected to those pins, just need to make sure that they are connected with the shorter lead to those pins during the swap.

Easy fix!

Sources:
http://web.archive.org/web/20110826134445/http://www.aikenamps.com/OutsideFoil.htm
http://www.aikenamps.com/index.php/where-to-connect-the-outside-foil-on-capacitors
http://www.partsconnexion.com/capacitor_film_vcap_cutf1.html
http://www.laventure.net/tourist/caps.htm


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## lucidreamer (Sep 27, 2017)

I got the Mundorf caps from Victor today that I ordered last week and just installed them into my Elekit replacing the C3, C4, C9 and C10 while changing DB107 to DB207.

Honestly I was initially skeptical about the coupling capacitor upgrade but after the swap there is a definite improvement in audio quality that I noticed right away. I compared using the same uncompressed which are familiar to me and the same music really opened up. It feels more transparent and effortless now with more space between instruments and better clarity for each note. The resolution is definitely improved too with more bass and high notes articulated. Interesting how they would sound after the break-in too, I would not

Overall I like how they sound, they have that pleasant touch to the high notes that can be rendered as some coloring to the sound maybe. But it does not sound too colored or syrupy at all, it just feels right by keeping the tubey character of the amplifier intact.

Not that the AMTRANS are bad capacitors but these German-made ones are really a step up and improve the quality of audio. I think they are worth the money and Victor sells them at a reasonable price and he would ship them fast. Some stores may take a few days to ship them out and it may be much longer to wait for them to arrive from Europe for those who live in the States like me.


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## lucidreamer (Oct 4, 2017)

I just got a pair of identical NOS RCA 6L6GC blackplates w/bottom getters that I recently won on eBay. They cost pretty high but still lower than what the dealers would charge for those tubes these days.

They appear to be in great shape and only lightly used based on the overall condition, flashing, etc. I do not have the tester to confirm their readings but the seller said he would accept the return or work with me on issues with them. As usual the seller stated that they were new and tested as new but we all know. I doubt that it is possible to find real NOS RCA blackplates these days anyway which were never used. They came with original RCA carton boxes with a musty smell which was a good sign that they were sourced from the same place.

The sound is pretty nice and clean overall but compared to GE 6L6GC with large cooling fins that are my favorite ones - I do not really hear a dramatic difference that would justify the 3-4 times more price for them opposed to GE ones. Yes, the bass seems a bit tighter and the RCAs sound a little more dynamic and cleaner but there is no day-and-night difference as I thought it would be. They sound more like my new Philips EGG 7581A that I recently put on sale after switching to GE.

Should I give them a few days to burn-in and settle maybe? If they were laying in storage for 40-50 years, then it may take some time to 'wake them up' to sound best maybe. Is there a possibility that they were heavily used already and still showing the good flasher left? Should I keep them, suggestions?


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## Effusion (Oct 4, 2017)

I agree with you regarding the RCA blackplate 6L6GCs, I also don't think they are really worth the extra coin, compared to the GE 6L6GCs, which can really be a deal if you search and are still my personal favorite 6L6GCs.  Your impressions also sound very similar to mine as well, to me the RCA's are a bit cleaner, refined, with tighter bass, but at the same time, they sound a bit too clinical to me at times and generally have a lot less of a lush sound than the GE's tend to give.  To me the GE's also have more bass impact, if a bit bloated at times, but I prefer the overall tone they give compared to the RCA's, which to me can sound a bit sterile and almost too clean.  To generalize, to me the RCA's seem to be more solid state than the GE's, which may be a good or bad thing based upon the signal tubes, the headphones/speakers, and one's own preferences, but to me they always just took too much of tubey goodness out of the mix, where the GE's accentuate it.  However, I for one really like the tube sound in general, so I tend to gravitate towards those.

With that said, generally I've found that many of the NOS versions of tubes that many people rave are the best online are in fact just a bit more solid state sounding overall than their less raved about counterparts.  That is they tend to give a tighter, more controlled, and precise sound.  I also believe that many who go from say something like a GE to a RCA 6L6GC automatically believe they are superior because of their tightness and overall cleaner sound, even though it isn't by much, translating this into a perceived higher quality.  Taking this into account, it is still really hard to tell unless you try them out for yourself, but knowing this generality and where you typically land on the continuum of tubey versus solid state, can help determine if the cost is worth it to you beforehand.  Don't worry though, so many are crazy about the RCA blackplates, especially those who read up on them online, that you should have no trouble selling them if you ultimately determine they are not for you.  Another option is to hold on to them for a bit if you don't need the cash right away, get them properly tested, and sell them in a year or two down the road.  The prices are only go up these days, especially for those that have large followings online or are talked about more.  As more and more folks get into tube amplifiers, the ones that are considered the cream of the crop get snatched up quickly, at almost any price it seems nowadays.

I tend to find that burn-in on tubes, while necessary, isn't like their solid state counterparts, in that they don't take as long, but still require some time.  I would say that generally a couple of hours of burn-in is really all that is needed for most tubes, with 24 hours being the absolute max to cause any real difference in my opinion.  Now, this isn't just for true NOS, but also for those that haven't been used in many years, so it is always best to wait a couple of hours before judging critically, even if they are used when you purchased, as you never know when the last time they really saw some use was.

As a side note, I'm glad you are liking the Mundorf's!  I like them as well, as do several others here on this forum, and your impressions are once again, similar to mine.  The caps seem to open up the sound a bit, giving more definition between the notes, a bit more of a cleaner sound, a bit more detail, and to me, sound a bit more natural than the AMTRANS overall.  To me the highs seem to be more extended and a bit more present, but it is hard to tell now as it has been so long since I did the upgrade and it was the highs that seemed to have changed a bit after about 30 hours or so of break in.  In addition, prior to the upgrade I wasn't able to use my amp for several weeks, so my reference at the time wasn't great.  It seems like you really got a baseline and were able to get better impressions than I was.  It would be nice to compare a stock version to one whose only difference is the Mundorf caps, but generally I also think it is a worthwhile upgrade for those on the fence, especially considering what some NOS tubes cost, even quality new production, and if you think about it, this upgrade will affect every tube you use with it, whereas the tubes are strictly self-contained.  Give it a bit of time and see if you notice any differences as they burn-in a bit.

As another side note, to those that are interested in the 8600, I'm hoping to get some good impressions of it this weekend when I see Victor at RMAF.  I spoke with Victor a few days ago over the phone and he really likes it!  He told me that it is so quiet that it's scary and that the tone is absolutely amazing, especially with piano.  I'm really excited to hear it and spend some time with Victor again.  More to come...


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## lucidreamer (Oct 4, 2017)

Thanks Effusion, great points! I will probably keep the RCAs to myself, both GE and RCA tubes are superior and possess that nice tubey tone that makes everyone want to listen to the music for hours, it is both transparent and warm without being dark or too bright and fatiguing. The tendency is that those NOS tubes will be very hard to come by regardless of price.

I agree 100% that if the tube sounds too solid-state and bright, it may appear as a benefit at first, but after a while one realizes that it is a too fatiguing to listen to that setup for longer periods of time. I remember experimenting with solid-state PPA headphone amps a few years ago and based on some online suggestions I experimented with video opamp chips that have frequency of several hundred mHz. After dealing with oscillation issues at first, I finally made it work and it did sound like nothing I ever heard before, very quiet and extremely resolving. But it was discomforting and fatiguing, after a while you get a sensation of tiny ringing in your ears like after taking a plane. It was not a pleasantly-sounding setup at all, I pulled those chips out later and put the audio ones back in, it is still laying around in the drawer, the PPA amp after coming across Elekit. I think the problem with the video opamp chips was too much high-frequency and ultrasonic noise creeping in that would need to be specially filtered out or something.

Yes, the Mundorf upgrade was definitely 100% worth the money, no regrets whatsoever. After about a week - they seem to relax a little bit and sound even better and a little laid back. Maybe that was after I switched to Mark Levinson 360S DAC recently which really sounds amazing and vinyl-like despite the age. On a side note, the iFi Micro iDSD DAC that I used before with Elekit is also very fine-sounding DAC. I spent like 3-4 hours doing some A/B tests between the Mark Levinson and iDSD and despite the huge price differences the iDSD rivals the ML in all aspects. The ML indeed has better bass and wider soundstage and sounds more fluid maybe; it has some unique mellifluous voice with a higher authority found in serious equipment. But as for details and transparency - they are both on par as I did not notice much or any differences between both DACs and I can surely tell the difference. It is really amazing how audiophile technology progressed in the last dozens of years and became affordable for everyone and not just for rich guys and gals. The latest version of iDSD Black is around $400 new and it is a great portable DAC/headphone amp that sounds way better its price range, I think. I now use it as a USB -> SPDIF converter only with external DAC.

I think I am going to stop the upgrade journey for now and settle on that existing setup to just enjoy the music.


----------



## Effusion (Oct 16, 2017)

For those who are interested, I was able to briefly audition the new Elekit TU-8600, Victor's version, last weekend at RMAF.  Here is a link to my impressions (which are towards the bottom): Link

I also took a few photos of the 8600 as well as the other equipment at Victor's table while I was there this year, so I've posted them below as well.  It was really great to see Victor again this year and I enjoyed the time I was able to spend with him and at his table.

              

As far as more direct comparisons to the 8200, it's really hard to tell and I would need more time with the 8600, plus at least two options with the tubes for it.  I think ultimately the 8600 may have better layering, resolution, and resolve, with a slightly quieter background, but I would really need each side by side and with different tube types for the 8200 to get a better idea.  However, I did notice that the 8600 unit needed a bit more time to break-in towards the end of my listening, which was confirmed right after by Victor.  It sounded very nice as it was and all I'm thinking now is how it will settle in with a bit more time, plus what other makes of 300Bs would adjust the sound.  As it was though, I can say that it was as good as the 8200, even a bit better in several places, so comparable and close to me with really nice sets of more dynamic tubes, such as the KT-66/88, 6550, and 807, in the 8200.  While there were places that I would have liked better, even some that I would have liked better if they were more like the 8200 at times, overall it definitely impressed me in several ways.  I would say that if one was looking for a punchy, versatile, and great seductive sounding amp, without feeling the need to swap out the tubes like I do at times, this may be a great model for you.  Ultimately I would need more time with it and in my own chain.  I also really like the options of tubes I have for the 8200 currently, in addition to its size, however if I could ever finally decide on which pair of single drivers I want to try, I think this amp would be both very fun and sound great in this type of setup.  Being able to fully take advantage of both speakers and headphones at the same time on some really nice 300Bs sounds pretty good to me!

My thanks to Victor and all at Elekit who keep making all of this great gear!  I'm keeping my eyes on this one...


----------



## sotto123

Has anyone had the chance to compare the TU-8200 to the Mogwai? 

I'm curious because both take 6L6GC tubes.

I generally prefer a warm, rich sound which I think both would offer.


----------



## fccn75

Hello All,

Been enjoying this amp for awhile now since my FET catastrophe last year.  Three questions I like to throw out:  DC offset from source to TU8200 input, using12BH7, and using 12AX7.

According to our amp's schematic, it is DC from input connectors to output transformer.  How high of a DC offset from i.e. DAC output can it take?  I know common knowledge is less than 100mV for typical designs, but this input appears to right at the grids after the 50K pot.  Can it take more than 100mV without any consequences?  

There were posts regarding the use of 12BH7 awhile ago, that it was quite preferred over the 12AU7.  I am thinking of trying it but the higher current drain at the heater and different plate resistance is a concern for longevity of the amp.  How has it been for those who have used this tube after all this time?

12AX7 - high gain tube.  I have a passive I/V stage using a current injection and a single low value resistor on my TDA1541 diy DAC that only puts out 70mV or so.  On headphone out using the standard 12AU7, I can get pretty decent sound when I push the volume close to 4:00 which on a standard DAC would be damaging to both headphone/ear!  Instead of using another line-stage in-between, just toying with the idea of using a high gain tube like the 12AX7.  What do you all think?


----------



## fccn75

Whoops, meant to say amp is DC from input to before the power section!


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## Dimu

fccn75 said:


> Hello All,
> 
> Been enjoying this amp for awhile now since my FET catastrophe last year.  Three questions I like to throw out:  DC offset from source to TU8200 input, using12BH7, and using 12AX7.
> 
> ...



Regarding DC- what do you mean "DC from input connectors to output transformer"? There are tubes and coupling caps in the amp. 

I would not stick 12AX7 into this amp- not a good idea. Read the thread on what's involved in using 12BH7 or E80CC. I tried Brimar 12BH7 and even though I liked them more than 12AU7 I much rather prefer E80CC. It seems like I am not alone in appreciating E80CC- somebody just bid up a rare version of E80CC to $599 for a single tube! That would be $1200 to drive this amp, before you even pay for the output tubes which are usually costlier than driver tubes 

https://www.ebay.com/itm/E80CC-6085-PHILIPS-tube-PINCH-DISC-getter-SMOOTH-plates-46-WKB/311998787509


----------



## fccn75

Hello Dimu, I was trying to convey that this amp is direct coupled from input (rca jacks on back) to the 12AU7 grids after the volume pot.  The only signal coupling cap is between the output of the 12AU7 to the next stage taken over by the 6L6 power section.

No go for 12BH7...no go for 12AX7 but ok for E80CC, I'll do some research on this tube.  OMG, $599 for a single tube, no thanks!!!


----------



## Dimu

If you can run E80CC you can also run 12BH7.


----------



## gasmonkey

Noob question, I own a Tu-8200 (love it), and have the opportunity to get a used tu-8500 at a good price locally. I use a line in only, (Chord Mojo -> tu-8200), dont own a cd player or record player. All digital files.


Would this be of benefit too me? I'm failing to see how it would benefit me, but have have a couple people tell me a preamp will always improve my sound.


----------



## vkung

Yes.. you use TU-8500 as a tube buffer...


----------



## Dimu

gasmonkey said:


> Noob question, I own a Tu-8200 (love it), and have the opportunity to get a used tu-8500 at a good price locally. I use a line in only, (Chord Mojo -> tu-8200), dont own a cd player or record player. All digital files.
> 
> 
> Would this be of benefit too me? I'm failing to see how it would benefit me, but have have a couple people tell me a preamp will always improve my sound.



I enjoyed building TU-8500 even though I wish there was more room in the case to be able to upgrade more components. It certainly does not hurt having this preamp, I always use it with my TU-8200. As for how much it helps- if you only feed it with your DAC the only difference is going to be more second harmonic distortion than TU-8200 alone. The way this works is that you crank volume up on TU-8500 and attenuate it way down with TU-8200 volume pot. In fact for that configuration I would replace TU-8500 volume pot with a fixed 50k resistor soldered in so that those preamp tubes get to produce maximum distortion. 

If you are not building it yourself I would say your money is better spent on some nice tubes for TU-8200 than getting preamp, and also on upgrading components in TU-8200. A well upgraded TU-8200 alone will sound better than stock TU-8200 paired with stock TU-8500. Of course when I say nice tubes I mean real tubes, not the stuff that communist factories produce today.


----------



## Sir Gaben (Dec 27, 2017)

Hi

I'm thinking about tube rolling and I wonder if the 807 tube is the best choice? Ore are there more superior tubes out there?


----------



## Dimu

Sir Gaben said:


> Hi
> 
> I'm thinking about tube rolling and I wonder if the 807 tube is the best choice? Ore are there more superior tubes out there?



Cossor 807 is not "the best", but a decent choice, especially with stock power transformer. The best require power transformer upgrade. EL12 spez is what has been in my amp for a long time, driven by E80CC. TT21 or genuine GEC KT88 driven by E80CC produce special sound too, but this little amp can't sustain the resulting thermal load comfortably. Same goes for various genuine 6550 like Tungsol, GE, Sylvania. With EL12 spez things run cool continuously. Genuine GEC KT66 has great sound too. Some of these tubes will cost you more than the amp itself though, so I doubt there will be much "rolling". EL12 spez used to be reasonably priced but the source in Germany dried up for about half a year now. Same goes for Dutch E80CC- used to be plentiful just a year ago, much more scarce now. E80CC will last for very long time though, so grab some while you can and enjoy.


----------



## Dimu

Dimu said:


> It seems like I am not alone in appreciating E80CC- somebody just bid up a rare version of E80CC to $599 for a single tube! That would be $1200 to drive this amp, before you even pay for the output tubes which are usually costlier than driver tubes
> 
> https://www.ebay.com/itm/E80CC-6085-PHILIPS-tube-PINCH-DISC-getter-SMOOTH-plates-46-WKB/311998787509



Just checked that link for the final price- $676.00 for a single preamp tube...


----------



## Sir Gaben

Thanks Dimu for answer. The 807 adapters will take some time before they arrive. 

I saw some E80CC tubes on Tubeampdoctor pretty cheap; 71,50 euros but it's unclear what brand they are selling.


----------



## Dimu

Sir Gaben said:


> Thanks Dimu for answer. The 807 adapters will take some time before they arrive.
> 
> I saw some E80CC tubes on Tubeampdoctor pretty cheap; 71,50 euros but it's unclear what brand they are selling.



Those are three Dutch tubes pictured on Tubeampdoctor web page. The price is relatively high for just one tube (or maybe it's ok considering that price includes VAT). That crazy $676 price was not for a regular E80CC, it was the rare "pinched waist" version. I used to buy E80CC for $80 to $90 per pair a year ago.


----------



## lucidreamer

NOS Dutch E80CC tubes can still be grabbed from eBay under $100 for a pair if one is patient. I ordered mine from Germany last time in September and it took a couple of weeks to arrive - Valvo-labeled Heerlen E80CC ones. There are also some Amperex E80CC which could be made in the US (silver pins) but these should sound about the same as Heerlen ones based on online reviews. The E80CC will be hard to get at this price pretty soon anywhere.

NOS Valvo E80CC and RCA blackplates are what I use for the last 4 months without tube rolling and am pretty happy about the sound. Recently changed my DAC to a Non-oversampling TDA1451-based one and it was a huge sound upgrade too. Still waiting for the Femto-clock board to arrive from Eastern Europe, it has been 3 weeks almost and still waiting. Holidays.


----------



## Dimu

I've been planning to play with vinyl from the time I ordered TU-8200 and TU-8500 but never had time to actually do it. At about the same time I ordered Burson discrete op amps for the phono preamp section of TU-8500. So I finally cracked TU-8500 open to stick in those opamps. Looks interesting next to the preamp tubes:


----------



## Dimu

While the preamp was opened I measured Mullard CV4024 tubes that I have in there, and also checked E80CC that I've been using in the amp. Both show considerable drop in transconductance. These tubes do wear, even though E80CC is supposed to be 10,000 hours rated. And my EL12 spez are showing some drop in plate current but nothing crazy. I figure my tubes are probably good for another year but sometime in 2019 I'll have to swap at least some of those tubes out due to wear. If I don't roll them for fun sooner that is


----------



## Dimu

So I got bored and popped CV8286 (TT21 which is GEC KT88 with top anode) into the amp. Bass is much better controlled and volume on speakers can be pushed much higher while sounds stays clean. It is actually enough clean power for a big room even with LS50. But compared to EL12 spez many recordings sound too bright. While it is fun and pleasure to listen to these tubes, I think EL12 spez will go back into the amp at the end of the day...

I am planning another upgrade project for this amp- will see if I can improve B+ rectification. Need to order a few parts and then spend some time measuring, upgrading and then re-measuring. And this is where TT21 will be useful as it loads B+ more than smaller tubes.


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## Sir Gaben (Jan 21, 2018)

The 807's are here!


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## puderay (Feb 25, 2018)

Hi, I am new here but would like to share the modification that we designed for the TU-8200. The idea was to lift the performance and musicality of the amp, in a simple and inexpensive way. We go further than just exchanging recommended parts like caps, VR and tubes, we really change the electrical design, though in a safe way and considering the power supply capacity.
Elekit's products are absolutely fine as they come. The designs are good and so are all components. You won't find any imbalance there. The price/quality ratio is simply great. Because of this we think they are nice platforms to do something interesting with. So what did we do ?
- Although very commonly applied, also in high-end amplifiers, we find the 12AU7 sounding somewhat dull, and often the circuits around it are a bit slow and therefor the powertubes aren't driven well. We use NOS 6n6p tubes, which are rarely applied, but in fact combine good performance with a great musical quality. The 6n6p tube is a different type than the 12AU7, and therefore we rewired the tube sockets to the PCB. This implies that afterwards no other type of pre tube can be used !
- We power the 6n6p tubes in the anode circuit with a cascade type Constant Current Supply, using 10M45 mosfets. This brings 3 great advantages:
1.  It gives  a lower load to the 6n6p tube which results in a very good linearity.
2.  There is a lower output impedance and by that a lower Miller effect in the power-tubes. This is an excellent way to drive the power-tubes !
3.  And last but not least, it improves the PSRR significantly, which results in much less  distortion and better sound quality.
- We took out the overall feedback system. Overall feedback makes an amplifier sound dull.
- We added local feedback on the power-tube 6L6GC.
- We took out the switching possibility for triode/ ultra linear/ pentode mode, and fixed it to pentode mode. This gives the maximal power output for this amplifier. With our modification, the pentode tubes behaves like a linear triode because of the local feedback. This type of set-up is called super triode connection amplification. This combines the higher pentode output power capacity with the more musical ability of a triode.
-  In this configuration, we found that the original Electro Harmonix 6L6 tubes can outcompete other possible tubes like the KT88, in this amplifier. The combination 6n6p + 6L6 is fixed. Tube rolling with other type power tubes is not advised because the voltages and currents will not match or not be sufficient. And as already mentied it is certainly not possible to apply any other pre tube.              The EH 6L6GC is in the top of new 6L6 tubes. Of course, with NOS tubes like the Sylvania or even the Philips 6L6, the amplifier will give an even more refined sound.                                                    Output power : 2x 6,5W                                                                             
-  We upgraded the coupling capacitors, but we don’t see this as a tuning matter; we don’t apply typical ‘audiophile’ (expensive) capacitors. Those often come with certain sound characters and colorization. To us, the components in this function need to be neutral, and we have spent many time and effort to source for this quality. We have a rather unique process of defining the sound quality or grade of neutrality when comparing capacitors.


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## Sir Gaben (Feb 26, 2018)

I would love to hear more about these mods...


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## puderay (Feb 22, 2018)

.


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## wantech

what is the best upgrade output transformer for tu-8200 ?  Landahl ?


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## puderay (Feb 25, 2018)

wantech said:


> what is the best upgrade output transformer for tu-8200 ?  Landahl ?



Lundahl is one of the more famous brands that supply excellent transformers, though I doubt that it will be worth the money to replace the original transformers that come with the kit. EKJ realizes very well that these are key components and they provide good ones. Replacing them with Lundahl or similar brands will easily cost you USD500-600, but will probably not make that a big difference. Personally I don't see the point in doing this while there are other changes thinkable with significant effect but against much lower costs. Apart from that, replacing original components with more 'audiophile' ones is more a matter of taste and preference than in an objective way making it better. It's a very subjective matter like changing capacitors; choosing for either Lundahl. Sowter, James, Iso Tango, Tamura, MagneQuest/Peerless  and the like. They are all good but i.m.h.o. you can't really rank them.


----------



## Dimu

cleaned up B+ power today. This measured at test point 25 with 100x probes before upgrade:





This is after upgrade:





Notice that "before" screen is 2V/divisioin and "after" screen is 0.5V/division. So 4x improvement in 120 Hz ripple plus eliminated high frequency from B+ power.


----------



## Dimu

This is how B+ area looked before the upgrade, notice stock D5 (in front of PTC) and stock C22 (big black cap):






This is what I replaced C22 with. My stock C22 measured at 160 uF and the replacement measured at 300 uF, and I used two of them which is why ripple went down 4x:


 


Cap installed, plus D5 replaced with Cree Silicon Carbide Schottky diodes:



 


View from the top- the new cap is touching bottom of the case so needs to be isolated:



 


Second cap is compression-fitted behind the left output transformer:


----------



## Sir Gaben

Any sound difference?


----------



## Dimu

Sir Gaben said:


> Any sound difference?



My ears think so 

But I have not bothered to measure. Could have measured distortion before and after.  This power feeds into three plates sequentially so impact should have been more than measurable. I would have played with some inductance to clean it up some more but that would require changing the board which is too much for an experiment.

What I noticed though is that all my B+ measurements are about 20V above the top thresholds specified on the diagram. Must have something to do with my custom power transformer. All tubes I use are in spec though with the higher voltages so I don't worry about it. Especially power tubes have good margins on spec'ed plate voltages.

Now I am thinking of checking ripple on my TU-8500 preamp. And I'll need to do some tube rolling to see how this B+ feeds KT66, TT-21, etc. I've been using EL12 spez pretty much exclusively, really love those Berlin-made treasures.


----------



## Dimu

Stress testing new B+ power with TT-21. The sound is amazingly deep, rich and vibrant. Low frequencies are very well defined, tight and pronounced. I think the bigger core of my power transformer is contributing here as well.

These really are the best tubes for this amp once all upgrades are applied. Except for thermals- the whole amp runs much hotter than with EL12 spez.

Also this amp now drives LS50 with clean sound so loud that I can almost enjoy the sound while wearing Peltor ear muffs designed for firearm range use  EL12 spez puts out a small fraction of that power before things get crippled.


----------



## dawktah2 (Mar 18, 2018)

Hello All,

I am a Head-Fi'er and decided to build me a 8200.  I originally wanted the DX but it wasn't available but they were selling the capacitors separate so I am building an 8200DX.  I have completed all the soldering without any additional modifications.  I will begin installing in the cabinet this week.  Took this pic after completing Board 1 and working on Board 2.

After completion and testing will build the 8500...?

Oh, why does the 8600 not come with tubes?  I only read 50 posts back in the thread.

Lastly is there a table somewhere with all the compatible tubes not brands. KT88 is one of them for example.

--Chris


----------



## sunneebear

Looks like the polarity on your kanutering oscillator is reversed.  Don't want to blow the capacillator on your voltron regulator, damn things are expensive.


----------



## dawktah2 (Mar 19, 2018)

sunneebear said:


> Looks like the polarity on your kanutering oscillator is reversed.  Don't want to blow the capacillator on your voltron regulator, damn things are expensive.



What?


----------



## sunneebear

It's that round thingamajig next to the rectangular thingamadoodle.


----------



## dawktah2

sunneebear said:


> It's that round thingamajig next to the rectangular thingamadoodle.



Oh, next to the tuchem shocem killem?


----------



## sunneebear

Exactly.


----------



## Dimu

Just looking at your bench I can tell you that you are doing fine. Just keep soldering away 
while you are at it I would recommend swapping out the bridge that feeds power to the heaters. Get a 3A bridge so that you can allocate more heater power towards the driver tubes.


----------



## dawktah2

Dimu said:


> Just looking at your bench I can tell you that you are doing fine. Just keep soldering away
> while you are at it I would recommend swapping out the bridge that feeds power to the heaters. Get a 3A bridge so that you can allocate more heater power towards the driver tubes.



Is there are particular one you recommend and a source to buy?


----------



## Dimu

just look for something that fits, I had to do some creative bending to make mine fit. You can see a black square in the pictures I posted on the previous page. 2A is fine but I went with 3A to give it extra thermal margin.

You can buy components from any number of sources like Mouser, DigiKey, Farnell Element 14, etc. While you are at it might as well order a few other upgrades to have them thrown into the box to make shipping cheaper on per-component basis. And get a few spare MOSFETs if they still sell them (they are discontinued). Those things will burn out if you mess up anything on the tube end.


----------



## Effusion (Mar 20, 2018)

Hey dawktah2, welcome to the club!  You'll have to let us all know how it sounds after you get it built, etc.

As far as tube equivalents, there are a ton, and if you do some modifications such as Dimu has, then it even opens up even more possibilities.  Many here have tried a ton of different types, old and new, as well as in many combinations, so don't hesitate to ask.  I think the 8600 doesn't come with tubes to keep costs low... as it does use the 300Bs, etc., which aren't cheap and can be damaged during shipping along with the kit.  The tube set that comes with the stock 8200 is fairly cheap, especially the input tubes, and since a lot of the power tubes are used in guitar amps, there is plenty out there as new stock anyway.  Best to always go with your own tubes in the end though, as generally cheap plentiful tubes are sent stock with almost every amp, and while not always, they generally don't sound as good.  I have met some that just use the stock tubes, but many do not, as most use them as just a test to make sure everything is working correctly.  The great thing about this amp is that it gives you a ton of possibilities, which maybe to some is a bad thing, but there is always something that can be done or tried differently, which can keep the excitement up after many years and also help hone in on that elusive perfect sound.  Synergy is often best.

As far as places for information on variants, I don't think there is really one source, at least that I currently know of, but check out the following when you get a chance as they may help a bit, if not provide more information:

http://www.vacuumtubes.com/12au7.html
https://www.tubemuseum.org/SearchResults.asp?Cat=30
https://www.radiomuseum.org/tubes/tube_6l6gc.html
https://www.tubeworld.com/index_high.htm

Since the amp has that auto-bias feature, it makes it really easy to swap between different types.  Some you'll need adapters for, such as the 807 and similar variants, while I also use quality socket savers for many NOS EL34s, because their pins are often not tapered and can really wreck havoc on your sockets, etc.  If you do come across a pretty comprehensive list of variants that can be used with the stock amp, let us all know.  We all probably should have compiled one by now and also put which ones you can use with Dimu's mods, etc...

Once again, welcome, and I hope the rest of the build goes well!

EDIT:  Now while it is not comprehensive, at least I don't think so, and doesn't include the ones Dimu uses with a modified unit, in the first post, the review, I do list some that can be used at the bottom of the list of specifications/features.  Will help you get your feet wet at least.


----------



## dawktah2

Thanks!

I'm up and running and had a chance to listen a little bit last night.  Stock tubes have way more low end than I am used to from my Woo WA-8.  With nothing connected full volume silent (to my ears).  Connected DAC, soon to be replaced, placed track on pause, same test, silent. Now that I have it running will be upgrading the tubes! I'm probably going to change LED to blue.


----------



## vkung

I'm up and running and had a chance to listen a little bit last night.  Stock tubes have way more low end than I am used to from my Woo WA-8.  

Here is the magic..
If you change the stock 12AU7 to something better , you will hear more detail from TU-8200.


----------



## dawktah2

vkung said:


> I'm up and running and had a chance to listen a little bit last night.  Stock tubes have way more low end than I am used to from my Woo WA-8.
> 
> Here is the magic..
> If you change the stock 12AU7 to something better , you will hear more detail from TU-8200.



Thanks for the tip!

Ordered some NOS RCA matched pair about two hours ago.


----------



## vkung

dawktah2 said:


> Thanks for the tip!
> 
> Ordered some NOS RCA matched pair about two hours ago.





dawktah2 said:


> Thanks for the tip!
> 
> Ordered some NOS RCA matched pair about two hours ago.


There are a lot of good  12AU7 available.  You can try PSAVNE 12AU7 MK2.
The next step.. you can upgrade the coupling cap to Mundorf EVO Supreme Silver GOLD...


----------



## Effusion

Congrats on the build!

Yes, while the stock tubes will get you up and running, at least those 12au7s aren't very good.  However, I actually never used them, only for the picture of the final build in the review, just never really wanted to as I had already bought replacements.  There are a ton of avenues you can explore as far as tubes go though.  While I and others tend to prefer NOS to new stock, but many others have had great success with the new stock Psvane tubes.  I would not recommend some of the cheap new stock Chinese and Russian brands, but there are a few out there that are okay and many enjoy.  Really about what you want in the end as prices can be quite high for certain types, especially NOS.  I also second Victor's recommendation on the Mundorf EVO Supreme Sliver Gold caps, they made a very nice improvement to my unit and others have reported great results as well.

Best thing to do is to probably try out those RCAs you got with the stock power tubes and then let us know where you'd like the sound to go.  In general, some types will give you more impact, more mid-range, more bottom-end, more highs, etc.  Then there is also the option of doing some mods that Dimu has done in order to run some other amazing sounding tubes as well.

Another thing to keep in mind is that it took at least 30 hours before the amp started to settle in, at least for me, so it may change over time in the beginning.  I too run the blue LED, but remember that you can also switch between output modes and certain combinations of this paired with certain power tubes can give really good results as well.  Just let the amp sit unplugged for at least 10 minutes before opening it up and switching to be safe.

Cheers on the build!


----------



## dawktah2 (Mar 20, 2018)

Thanks Everyone,

Are there any clearance issues with the Mundorf caps? Buy same specs the same as the DX caps?


----------



## dawktah2 (Mar 20, 2018)

Effusion said:


> Congrats on the build!
> 
> Yes, while the stock tubes will get you up and running, at least those 12au7s aren't very good.  However, I actually never used them, only for the picture of the final build in the review, just never really wanted to as I had already bought replacements.  There are a ton of avenues you can explore as far as tubes go though.  While I and others tend to prefer NOS to new stock, but many others have had great success with the new stock Psvane tubes.  I would not recommend some of the cheap new stock Chinese and Russian brands, but there are a few out there that are okay and many enjoy.  Really about what you want in the end as prices can be quite high for certain types, especially NOS.  I also second Victor's recommendation on the Mundorf EVO Supreme Sliver Gold caps, they made a very nice improvement to my unit and others have reported great results as well.
> 
> ...



What are the specs on the Mundorf capacitors? Can't make out in post #797


----------



## Effusion

Probably best to get the details from Victor, as that's who I got my caps from.  You can source them yourself, but for me being in North America, it was easier through Victor and I believe he still sells the upgrade, which includes all parts.  I don't believe there are any real issues with the caps and mine have enough clearance.  To me they were a little quieter, with more air/breath as well as soundstage, a bit more sparkle up top, and a much more natural presentation overall.  However, this was going off of long-term memory, as my amp was out of service for a bit right before the caps were installed.  However, several members on this thread also did this upgrade and not only were the results positive, they also seemed to be similar.  Although it isn't a cheap upgrade, you have to take into account that it will affect everything else downstream and that includes really expensive tubes, etc., so it made sense to me at least in that regard.  Really up to you, as you might just want to get a feel for the amp and try some different tubes for now, then get the upgrade at a later date, or maybe it makes more sense to do it now, etc.  If I had to judge, I would say it was around 10% or so.


----------



## Effusion

dawktah2 said:


> Thanks!
> 
> I'm up and running and had a chance to listen a little bit last night.  Stock tubes have way more low end than I am used to from my Woo WA-8.  With nothing connected full volume silent (to my ears).  Connected DAC, soon to be replaced, placed track on pause, same test, silent. Now that I have it running will be upgrading the tubes! I'm probably going to change LED to blue.



Was just thinking... the power tubes you have are the Electro-Harmonix 6L6GC's right?  Hard to tell from the picture, but I believe the kit still comes with them.  Well, if they are, although I haven't really heard them in quite some time, I remember them being a bit boomy in places with quite some resonance down below.  Although the mid-range had some great detail, they seemed a bit weird at times and with a bunch of bloom at others, but detail was kind of foggy.  Anyway, I think changing the power tubes out as well as trying the RCAs, will help with clarity and tightness.  By the way, I really liked the 12au7 RCA clear-tops that can sometimes be had for cheap, otherwise I pretty much have always preferred their mil-spec, which is a different code than 12au7.  Otherwise, I seem to prefer other brands of signal tubes in general for this amp, same with some GE as well, although GE has one of the best 6L6GC and also 6550.

However, there are quite a few variants to choose from, but from the 6L6GC line you may be able to find an inexpensive GE pair, or even a nice set of 807s with adapters is fairly cheap and nice sounding overall, if with less soundstage and air and that sound quality can vary at times among the brands, they can be really tight, like a KT-88 (the early round/ribbed Cossor ATS25 are awesome, but hard to find).  The only problem is some variants for this amp can go for a ton of money, with NOS KT-88 impossible to really find, to basic EL34s going for well over or close to $100.  In addition, even the Psvane options are not cheap, and the fact that they all sound different, can make it hard not to spend a ton on them.  While there are some really great options to choose from, with some prices so high at times, your best bet may be to try to hone in on which might work best for your system and style of music, etc.

Hope that helps, but let us know.


----------



## dawktah2 (Mar 21, 2018)

They say there's no such thing as a dumb question; who is Victor?

I've left unit on since original post and sound is more even however stock tubes make piano sound like a digital keyboard.

Will give report after I burn in NOS RCA 12AU7

*Also, I'm only using headphones, so let me know which mods help for this purpose.*


----------



## Effusion

No worries, Victor is Victor Kung of VKMusic up in Canada.  He sells the TU-8200DX kit as well as numerous other Elekit amps, etc.  He's the guy, @vkung, who posted about changing the 12au7 out and trying the Supreme Upgrade, which are those caps.

Yeah, with some burn-in and a change to the RCAs you should get a different and better sound.  The 12au7s that came with my kit were very basic and just said "China" on the glass in red... I never trusted them, so I never used them.  No worries though, better to burn-in the amp on those tubes than anything else that is expensive.


----------



## dawktah2

Thanks, I'll order, and I'll just need the four or do I need to replace the others that came with DX upgrade?

*Also, I'm only using headphones, so let me know which mods help  for this purpose. Like bridge rectifier...?*


----------



## dawktah2

vkung said:


> There are a lot of good  12AU7 available.  You can try PSAVNE 12AU7 MK2.
> The next step.. you can upgrade the coupling cap to Mundorf EVO Supreme Silver GOLD...



Victor and others,

I swapped out the 12AU7 with the NOS RCA and the image is clearly brighter and therefore more detailed.  One of my favorite tracks the "sparkle" has returned.  I am looking forward to the Mundorf cap change.  What can I expect this this mod?  I am waiting on the Chord Qutest DAC (GIGO if you're wondering) which for some reason has been delayed in the USA. Later I will be swapping out the 6L6GC tubes.  With this eventual pairing I am beginning to wonder based on how this unit sounds right now how does it compare to units costing 5-10x its cost??? Being a newbie how much of the overall sound is determined by the tube itself and how much is the unit components and wiring?  I feel at this point I need to read return policy on any amp I buy very carefully, subtle nuances are they really worth thousands of dollars?

Thanks everyone!

Chris


----------



## vkung

dawktah2 said:


> Victor and others,
> 
> With this eventual pairing I am beginning to wonder based on how this unit sounds right now how does it compare to units costing 5-10x its cost??? Being a newbie how much of the overall sound is determined by the tube itself and how much is the unit components and wiring?  I feel at this point I need to read return policy on any amp I buy very carefully, subtle nuances are they really worth thousands of dollars?



_The profit margin for DIY kit is *very (very)* low. We do not have the normal markup ie. 45-50%. _

_Also y.You built the amp. You should know the quality of TU-8200. Just the Japanese  R-core is worth more than $145.  
Tu-8200 is made in Japan including the OPT and R-core....

No doubt  that  TU-8200's sound  is better than a lot of expensive amps.  
Also you can upgrade the amp according to your budget._


----------



## dawktah2 (Mar 24, 2018)

Thanks Victor,

I'll probably pick up an 8600 and build it and research each component during the build. I really like the tube cover, since I have a 5 year old daughter. The WA-22 and WA-33 look good, but I wonder if "I can hear" the difference between the Elekit and the Woo.


----------



## Effusion

Yeah, those stock 12au7s were holding it back and definitely try out some other power tubes soon as well, as those EH ones weren't really very clear at all from my memory.

Both the components and the tubes are very important, the components will affect everything else downstream and are more permanent than the tubes though, so always a good investment.  The tubes however will give you bits and pieces of what you want/like, affecting the overall signature and synergy with certain headphones/speakers.  So, the quality and type/brand of tubes is important, but you'll never really know if you like them until you try them.

The 8200 is a great sounding amp, especially for the money, and in my opinion beats many amps that are twice or more its price.  Plus, most amps don't have the flexibility and all the features that the 8200 has.  Thus, after 4 years I'm still really enjoying mine and have no interest in trying something new.  In the end it is all about synergy and believe it or not, but the little 8200 actually sounded better with the Focal Utopias than the truly amazing, and very expensive, Studio amp, at a meet I attended a few years ago.  At the time I had my Cossor round/circle plate ATS-25s running with a very nice pair of Amperex 7316s... both are hard to find and not cheap.  The funny thing is that they sounded just amazing with the Utopias, yet not as good as other options I have with my HD650s.  However, in this setup all that heard the Utopias out of it agreed that it was doing the best job, including the owner who has had trouble amplifying them well.  So, in the end you just have to try different tubes, etc. and get a feel for what works best with your cans and the music you enjoy, but know that when the forces of the universe align correctly, it can sound absolutely amazing and better than many/most.

As far as cost/benefit ratio, it is really all about diminishing returns.  Once you get to a certain price level, the improvements stop being so dramatic.  So really a personal question one must ask themselves.  What is 20% better worth, 15%, how about 10%, what about 2%, and so on.  The nice thing about kits like this one is there are generally more options to upgrade/tweak the unit to improve it.  Just as @Dimu about all the mods that he has done on his unit, truly amazing...

I believe some have built tube guards that work with their 8200, if you are worried about her touching them, etc.  I was a big fan of the WA22 for many years and was actually going to buy one prior to buying this amp.  There are some comparisons listed in my review on page 1, but unfortunately I haven't owned the WA22, so my impressions are from brief interactions.  I would say that the Elekit is on par if not better with the right tubes than the WA22 with premium tubes, plus it has more options/features.  If I was running balanced headphones than the WA22 would be the better option obviously, but I would recommend the 8200 over it and over many other higher priced quality units based upon several factors.

Glad it is starting to come together, only better sound from here on out as you upgrade and use better tubes.  Continue to let us all know how it is going...


----------



## dawktah2

Dimu said:


> Just looking at your bench I can tell you that you are doing fine. Just keep soldering away
> while you are at it I would recommend swapping out the bridge that feeds power to the heaters. Get a 3A bridge so that you can allocate more heater power towards the driver tubes.



I think I found a comparable size bridge on Mouser but 2A. Will this work? Markings on mine match left DB107 except missing "vhi4"


----------



## vkung

https://ca.mouser.com/ds/2/345/db101-107-32844.pdf

DB107 1A


----------



## Dimu

dawktah2 said:


> Thanks Everyone,
> 
> Are there any clearance issues with the Mundorf caps? Buy same specs the same as the DX caps?



No but you need to observe "polarity" so that outer foil is facing towards lowest impedance path to ground so that it dumps interference picked up by the foil instead of sending it onwards as part of the signal. Search this thread there was information on what that means.


----------



## Dimu

dawktah2 said:


> *Also, I'm only using headphones, so let me know which mods help for this purpose.*



Getting speakers and speaker wires would be the mod that would help in that situation 
This amp is very good for near field listening with desktop speakers. I use LS50.


----------



## dawktah2

Dimu said:


> No but you need to observe "polarity" so that outer foil is facing towards lowest impedance path...Search this thread there was information on what that means.



Will do!



Dimu said:


> Getting speakers and speaker wires would be the mod that would help in that situation
> This amp is very good for near field listening with desktop speakers. I use LS50.





Have desoldered the capacitors awaiting shipment from Victor.


----------



## dawktah2

Found this not sure if it was ever posted


----------



## dawktah2

I soldered in the Mundorf capacitors last night and gave the unit a quick listen.  It sounds different so will need more time to exactly evaluate how.  I really found the schematic I posted above as being more helpful than the one in the kit.  The print on the one in kit is way too small! Thanks to all those that helped!


----------



## Effusion

Sure thing, let us all know how it turned out!  Give it some time to burn-in though, at least 20 hours before being too critical.

In addition, check into different power tube options, as I think you'll get much better sound than out of the EH ones.  Many of us here have been through a ton of tubes in this little guy, so let us know what you are missing from the sound and what types of music you listen to most and we can try to help direct you to some nice replacements.

In addition, if you haven't experimented with the output modes yet, they can make a huge difference.  I personally prefer Triode for headphones and believe it sounds the best with more different types of tubes, but many run and really like Ultra-Linear mode, especially for speakers, which can be nice as well, but only good in my opinion with a few power tubes like EL34s, KT66, KT88, and particular 807s.  In the end, I tend to prefer the expanded soundstage, low end, smoothness/naturalness, and fullness/bloom of Triode with headphones.  UL is really nice in the highs and vocals have a nice crispness to them, there is also a bit more detail than Triode as well, but I find on headphones it to be a bit sharp and harsh with certain tones/notes, as well as having a smaller soundstage and less weight down below.

Cheers!


----------



## dawktah2

Effusion said:


> Sure thing, let us all know how it turned out!  Give it some time to burn-in though, at least 20 hours before being too critical.
> 
> In addition, check into different power tube options, as I think you'll get much better sound than out of the EH ones.  Many of us here have been through a ton of tubes in this little guy, so let us know what you are missing from the sound and what types of music you listen to most and we can try to help direct you to some nice replacements.
> 
> ...



Thanks for the advice!

I will listen for 20+ hours and report back.  Since I listen to open back headphones, Ether Flow to be exact, I'll give the Triode mode a try. I'm definitely going to upgrade the driver tubes as the stock ones I can't imagine being the best.


----------



## Effusion

Sounds like a plan!  Yeah, I would say that after about 20 hours or so, my caps settled, general hardness eased, highs tamed down, and the lows stiffened up a bit as well.  Now while not a ton, quite noticeable in parts.  Also, keep in mind burn-in with the output modes as well.  Also after about 25 hours or so, UL smoothed out quite a bit for me as well, and had about 30 or so on Triode when I noticed changes, but once again slightly different than the caps or UL.

There are lots of choices when it comes to tubes, more about where you would like to go with the sound and how much you are willing to pay.  Personally, I stay away from a lot of the cheaper new production options and mainly run NOS when I can or at least old production in general.  However, many run new production with good results, with quite a majority liking the Psvane brand of new production and other higher-end ones as well.  Cheaper, but decent, old options to start with are the 6L6GCs and 807s (with adapters), but brands and designs matter, while KT-88s are almost impossible to find, KT-66s almost the same, but expensive, and the same with many nice EL34s and 6550s.  In the end you'll probably end up with one of the nicer, but more expensive/rarer, types, but if you are looking for something cheap in the meantime many may work nice.

The crazy, but at the same time awesome, at least to me, thing about this particular amplifier is all the options and combinations that can be had.  If you were to take all the stock options, combined with the mods that @Dimu has done, you'd have an insane number of statistical possibilities.  Even after 4 years, this little guy still surprises me!


----------



## Effusion (Apr 11, 2018)

As a side note, prior to switching output modes, it is recommended to let the amp sit, unplugged, for about ten minutes before changing the jumpers.  Just something to keep in mind if you start "rolling" output modes, so you don't do any damage.

Once you get a good idea of the Triode mode, I would recommend switching to Ultra-Linear, letting it burn-in in a bit, just to see if you might like it better with the tubes you are running.  Even though I find Triode more pleasing to my ears in general, you never know until you try it, which with this amp is always an option.  I also find UL mode a bit cleaner and brighter, so it might help depending on your system and music tastes.

Also, the signal 12au7 tube shouldn't be neglected as well, as a really good one that pairs nicely to the power tubes will bring the sound to the next level.  Prices are all over the place, but no need to spend a ton at first, unless you want to.  In general I've had good luck with the militarized versions, the 5814-A, which aren't bad and a good starting place for the price (CBS, Westinghouse, and a few GEs are my favorite).  Other 12au7 variants are generally my favorites though, however they are also generally harder to find and more expensive.  My personal favorite brands of 12au7 and equivalents tend to be Mullard, Brimar, Amperex, Raytheon, Tesla, Telefunken, CBS, and Westinghouse, in no particular order.  Only certain GEs and RCAs impressed me at times though, but they can also be great when they do.  There are other brands that are great as well, but these brands made quite a bit of different options and are more plentiful in general.  Best advice I could give regarding tube choices is to first try to find which power tubes you like the most and then try different signal tubes to refine the sound to your liking and to the other tubes.  Synergy is often most important and you can always sell any that just didn't cut it in the end to finance new purchases.  However, let us know how the journey progresses with the tubes, as trying out every type of tube option is very expensive and time consuming; I'm sure many here would agree.

EDIT:  As far as new production, you could always just get the Psvane 12au7s and KT88s and call it good, at least for a bit.  They aren't cheap though, however although I've never owned them myself, I have heard them before, and they do sound quite nice and many do like them in this amp.  I've also had good luck with several higher-end guitar amp tubes, KT66/EL34, etc. (Groove Tubes and others) and also have a pair of KT-88 branded by McIntosh that are quite nice (productions in the 80's and 90's).  However, cheaper options from Russia and China aren't always the best sounding or reliable in many cases.


----------



## dawktah2

Any opinion of Sophia Electric EL34?

You also didn't mention trying Pentode mode?


----------



## Effusion

No real honest opinion on them, as I have never owned them, but I know that many have liked the brand.  I have a local buddy that really enjoyed their 6SN7s, and I've also read in forums that many owners enjoy them.  However, I've also read a few that didn't and what appeared to be a few problems with their manufacturing, thus why some didn't like them or had reliability issues, but that was years ago, so can't really give good advice at the end of the day on them unfortunately.  I would assume that they would be much better than other new production types that are cheap though.

I find that the EL34 in general is more mid-centric, with some great highs as well at times, but tends to be a little bottom-end light, at least with certain brands.  They can also sometimes be a little too thick at times in places, really depends though, and not as fast or with as much punch as say a KT-88 or 6550, even an 807 or 6L6GC.  I actually prefer them in UL mode, as opposed to Triode, as it really seems to open them up.  However, I can see them as being very nice for certain types of music and if you want some really nice full mids.  As far as NOS options, many prefer the Mullards and there are different series of production from a plant I believe was called Blackburn in England.  I've tried quite a few over the years, including the Svetlana (winged "C"), which aren't actually too bad for cheaper new production, the RCA Japans which were clearer and punchier and a later production date, while the Tesla "Blue" glass tended to be really open in the highs, but lacking a bit down below at times.  I also have quite a few Mullards, Telefunkens, Siemens, and Amperex which are all very nice, but different flavors.  Unfortunately NOS options aren't cheap though, so going with something a little less expensive, just to see if you like the overall sound of the EL34 beforehand, would be recommended.  A word of caution though, at least with old stock EL34s, for some reason certain ones have pins that are not tapered like other tubes are, that is they are flat on the bottom of the pin and thus, thicker, with no taper many times.  I always worried about them wearing out the sockets in the amp, so I actually use two really nice socket savers with all my EL34s, so that I don't cause damage to the amp's sockets over time.  I'm sure new production, including the Sophias, would be tapered, so shouldn't be as much of an issue with them, but boy when they are not tapered, they are tough little buggers to get in and out of the savers even.

Yeah, there is always Pentode mode as well.  However, would you believe that I haven't tried it yet.  I was actually going to give it a whirl in about a week or so, so we'll see how it does; takes some time as I'll have to burn it in a bit first.  I don't believe many of the users here run Pentode either, but you never know, maybe I'll like it more than Triode, or maybe you will too.  The nice thing about UL and Pentode when running speakers is they give you a little more headroom with twice the juice, with just a bit more in Pentode.  I was recently really interested in some nice signal drivers, so this also got me thinking that I should try this mode soon to get an idea, along with UL, what I might want to go with to eventually run speakers as well.  I'll let everyone know what I find out though, but in the end, always better to find out for yourself if you can, as things can always be different due to equipment and one's own ears, so give it a whirl too if you are interested.  I think the reason I haven't tried it yet is that I don't run speakers and I've been so pleased in Triode with headphones and had already given UL a try.  That's the crazy thing about this amp though, there is always something new/else to try, even after 4 years!


----------



## dawktah2 (Apr 12, 2018)

Ah ha!  After doing some reading the 6L6GC is a pentode tube and the triode mode allows the pentode tube to function as a true triode like the 300B, correct?  Thus the TU-8600 kit.  So I'll listen for a while then switch to pentode and give that a long listen.  Hopefully my new DAC will arrive soon  since sound may change with the Chord Qutest.

I wonder how I can get to compare a 300B vs. my 8200DX, Mmmm


----------



## Effusion

Very interesting and great find!  I'm not entirely sure, but it makes sense.  The output mode, Triode versus UL at least, does make a difference with the tubes though for sure.  Even though there seems to be an overall general sound to UL, I found that several tubes preformed quite differently than they did in Triode, so I'm sure Pentode mode will also be doing something to them as well.  I will definitely have to spend some time with the 6L6GC in Pentode mode soon as well.  As far as good, but cheaper, NOS 6L6GCs, I've always liked the GE ones, which are usually a bit cheaper.  I've tried the RCA Blackplate ones, but they were just a bit too thin overall for my tastes, bass was really tight and punchy with great highs as well, but the GEs were just more full, with stronger bass and more bloom.  However, many consider the blackplate RCAs as being the best in the line.  GE re-branded the 6L6GC many times for other retailers/manufacturers, so you might be able to find an off-brand GE 6L6GC for cheap.  The way to tell if they are GEs is there is a dot pattern on the glass somewhere.

Yeah, a new DAC will definitely change up the sound, so you'll have to let us know how it works out.  As far as comparing to 300B directly, might be difficult, but a 300B amp would work.  The newer 8600 Elekit amp is a 300B and sounded very nice at last year's RMAF.

Looked briefly into the Sophia EL34 and they look very nice, not cheap at all, but I'm thinking they may just be a bit cleaner/clearer than most EL34s, also with more life to them.  Just going off what others have said compared to the SED/Svetlana ones that I have tried.  The EL34 is a great tube and many here have enjoyed it over the years in this amp.  They are very musical and natural and in my opinion are great for any type of music where you want an emphasis on the mid-range or highs.  Before spending a ton on them, it might be worth it to try some cheaper ones first, just to get an idea of the general sound.  If you think you could resell the Sophias easily, might just want to go with them off the bat and then decide if they are worth it or do what you want them to in the end.

Just like everything in audio, tube rolling is quite the journey with this amp and often what you start with is not what you end with.  With so many options for this amp, it can be quite daunting at times, but just remember that if you don't like the sound today, a different tube tomorrow may change everything.


----------



## dawktah2

I just started part 3 of "Understanding Vacuum Tube Amplifier Schematics" by BlueGlow Electronics on YouTube and now I think I need to re-open my unit and take a photo to make sure my coupling capacitors are in the right orientation.  I haven't reached a point yet where inflow/outflow is explained in comparison to +/- so does anyone know the easy answer to this?


----------



## sunneebear

@dawktah2 
I also have the MrSpeakers Either and Aeon and my favorite headphone amp for awhile now is still the TU-8200.  I have gone back to the stock tubes in UL setting because to me they are lush while still being very balanced.  I really liked the Psvanes but the sets that I got did not last that long and they are pretty pricey.  The combination of my source, the Questyle QP1R, the stock tubes in UL and the MrSpeakers headphones seem to work very well for me.  Other tubes color the sound even if they are good but I want to stay with what I think is a well balanced sound.  When I ordered my amp from Victor I did go all out and asked for the best of everything he had.  I am really glad I did that.


----------



## dawktah2 (Apr 14, 2018)

sunneebear said:


> @dawktah2
> I also have the MrSpeakers Either and Aeon and my favorite headphone amp for awhile now is still the TU-8200.  I have gone back to the stock tubes in UL setting because to me they are lush while still being very balanced.  I really liked the Psvanes but the sets that I got did not last that long and they are pretty pricey.  The combination of my source, the Questyle QP1R, the stock tubes in UL and the MrSpeakers headphones seem to work very well for me.  Other tubes color the sound even if they are good but I want to stay with what I think is a well balanced sound.  When I ordered my amp from Victor I did go all out and asked for the best of everything he had.  I am really glad I did that.



Thanks so much, I think what ultimately will govern any more of my tweaks will be how Chord Qutest will sound.


----------



## dawktah2 (Apr 14, 2018)

I AM SO CONFUSED!  From reading schematic, I am truly a novice, and reading an earlier post by LucidDreamer the Mundorf capacitor goes pin 1/6 to short inflow wire.  I have installed mine and have cut wires but I thought I followed this.  After looking at photos none are the same.  I suppose labelling could change but which end has what appears to be a ring under the jacket, the foil?

My install, C9 and C10 are the same, C3 and C4 are opposite direction to each other.  All my capacitors the wire leads and labels matched:

So:
C3 ring foil right
C4 ring foil left
C9 and C10 ring foil down?







Other  installs:


----------



## lucidreamer

My capacitors orientation was correct, so was Dimu's. Check my previous posts, I explained why after doing some research.


----------



## JayKay47

One of the pics is my incorrectly mounted caps, that have since been mounted properly. The last pic is Dimu's, and are the correct orientation. 

On another note, I replaced the stock interstage cap in my Eddie Current Aficionado with Jupiter Copper Foil caps, and WOW, they are awesome. I may replace my TU-8200DX's Mundorf's with Jupiters...


----------



## dawktah2 (Apr 14, 2018)

Thanks everyone, I need to reverse C3 and C4


----------



## dawktah2

Ok, let's give it a listen!


----------



## Dimu

The biggest improvement in sound comes with good tubes. And different tubes sound differently. For example KT88/TT-21 results in very punchy lows. EL12 spez is very musical. The problem is that those good tubes are disappearing. E80CC drivers used to be plentiful. Now supply has dried up. You can still buy them but nowhere like couple years ago when big lots were sold off. GEC KT88, KT66 and Tungsol 6550 are very difficult to find now. EL12 spez used to be easy but no more. Cossor 807 is pretty rare now too.

The point is this- supply of good tubes is finite, it is dwindling, and for many tubes it is close to extinction. Grab some while you can. You'll be able to buy good caps or DACs in 10 years. Not so with good tubes!

This amp is designed for rolling tubes- you only need two drivers and two output tubes, you get auto bias and you can throw pretty much anything at it. Some tubes won't last because of low grid voltage rating (which is why I chickened out on trying WE 350B) but the usual options will work just fine. It is a shame to not be able to find awesome tubes to try and enjoy in this amp!

I was thinking of building a 211/845 tube amp however I can't find any of those tubes any longer and whatever is available is limited and priced way too high. And realizing that TU-8200 kit will go the way of those NOS tubes soon I got myself a second TU-8200 box- will build it when I feel like having another perfect little amp  My amp is ridiculously pleasing to my ears! Right now it is running TT-21 and E80CC.

Regarding DACs- I feed the amp with Gungnir Multibit. I bolted it under my desk so that I don't even see it. It is powered 24/7 and other than from the awesome sound I would not know that it exists. I am not going back to delta-sigma DACs.


----------



## dawktah2 (Apr 15, 2018)

Dimu said:


> The biggest improvement in sound comes with good tubes. And different tubes sound differently. For example KT88/TT-21 results in very punchy lows. EL12 spez is very musical. The problem is that those good tubes are disappearing. E80CC drivers used to be plentiful. Now supply has dried up. You can still buy them but nowhere like couple years ago when big lots were sold off. GEC KT88, KT66 and Tungsol 6550 are very difficult to find now. EL12 spez used to be easy but no more. Cossor 807 is pretty rare now too.
> 
> The point is this- supply of good tubes is finite, it is dwindling, and for many tubes it is close to extinction. Grab some while you can. You'll be able to buy good caps or DACs in 10 years. Not so with good tubes!
> 
> ...



Dimu,

In the same vein is the same thing happening to the 300B, 12AU7 and 12AX7 tubes? I am considering after successfully building the 8200 that I would give the 8600 a go. 

How I got here to this forum:  I was about to purchase a 2A3 driver tube headphone amp based on manufacturer reputation without having put any long hours into a tube headphone amp other than my WA8 which is a transportable unit and not a desktop. What are you really getting from units 3x to 10x the cost??? So far with only upgrading to NOS RCA 12AU7  I am very impressed. I am very curious what type of sound the Elekit 300B kit will produce. I have to do some research since I plan on having these amps for a while and without tubes...

--Chris


----------



## Effusion (Apr 16, 2018)

Couldn't agree with @Dimu more, that is the reality nowadays and with many amps, more every day.

Unfortunately there is still only a few really great options in new production overall as well, but that seems to be changing in recent years, at least somewhat, with more focus on quality than cost by many more, and with several companies leading the pack.  Although I have never owned one, as I have never owned an amp that uses them, the 300B is very well regarded by many and I have only heard them briefly a few times.  My understanding was that it is harder and harder to find really good cheap NOS 300Bs anymore as well though, which is the unfortunate trend... I remember years ago the NOS WE 300B being rather pricey as well and not really plentiful.  Also, as with a lot of the stock power tube options in this amp, the 8200, especially those used commonly in guitar amp gear currently as well, there are also new production 300Bs for the 8600 out there as options.  Unfortunately while I can't comment on really any of them, new nor old, I'm sure they all sound different and some are made better than others in general.

As far as 12au7s and 12ax7s, I don't seeing them as much of the problem as others are, at least right now.  While yes, some, especially rarer versions/brands, do go for quite a bit at times, there are still lots of NOS options and also quite a few new production out there as well in comparison, however they could always be cheaper.  I believe the 12ax7 is still more popular, at least in certain instrument and audio gear, than the 12au7s generally are, as the x's not only have different specifications, they are also said to be generally a bit more punchy, forward, and with higher gain, if even merely by what is caused with those different limits.  @Dimu has done some mods to run other options entirely than the 12au7 family and with really great results, so there are options there as well.  I would still say that the little 8200 has more easier options in this regard, that is the auto-bias and particular tube design, than most.  As Dimu stated, it was like this amp was made for rolling tubes, so easy, so many types potentially...

I was also able to spend some time with the excellent 8600 at RMAF last year at Victor's table, here are my impressions at that time.  Although do note that I generally thought the unit needed a bit more time to settle in, however, what I heard was really nice and as good, if just different, than my 8200 at its best many times.  I'm excited to spend some more time next year with it as well, so I'm sure I'll have more to comment on then.  Victor was running new production 300Bs I believe, however I don't remember the brand.  I kept imagining what a really nice set of WE's or others would sound like while listening as well, also thought it would sound amazing with some really nice single drivers in a controlled room...


----------



## Dimu

dawktah2 said:


> Dimu,
> 
> In the same vein is the same thing happening to the 300B, 12AU7 and 12AX7 tubes? I am considering after successfully building the 8200 that I would give the 8600 a go.



WE 300B is long gone. If you find anything cheaper than $3000 PER TUBE consider yourself lucky. This was the first tube to disappear completely.

Quality 12AX7 is much more scarce than 12AU7 which is rather plentiful. 12AX7 is high-mu tube used in different applications than 12AU7. TU-8200 is not designed for 12AX7, don't try it. And biggest improvement to TU-8200 sound comes from swapping out 12AU7 for 12BH7 or better yet E80CC. Read up on it in this thread, don't just do it because those tubes have twice as big plates as 12AU7 and require more heat to stimulate emissions over larger cathode.

Instead of building other amps I stuck to this little gem, made it excellent, made sure I have lifetime supply of awesome tubes and then got a spare amp kit 
In my mind you get better results by focusing on a good platform like this and making it perfect rather than trying to screw around with multiple amps.


----------



## Sir Gaben (Apr 17, 2018)

The WE 300B will be produced again and cost a bit over 1200 dollar a pair...

http://www.westernelectric.com/products/300b.html


----------



## Dimu

Sir Gaben said:


> The WE 300B will be produced again and cost a bit over 1200 dollar a pair...
> 
> http://www.westernelectric.com/products/300b.html



That would be cool if they really released it and made it as good as the original. Still, for $1299 per matched pair you can buy more than one very good NOS output pairs. But if those tubes are really good I'll be building TU-8600 with some serious upgrades... That would be fun to compare EL12 spez and TT-21 in TU-8200 to WE 300B...


----------



## dawktah2 (Apr 17, 2018)

Dimu said:


> WE 300B is long gone. If you find anything cheaper than $3000 PER TUBE consider yourself lucky. This was the first tube to disappear completely.
> 
> Quality 12AX7 is much more scarce than 12AU7 which is rather plentiful. 12AX7 is high-mu tube used in different applications than 12AU7. TU-8200 is not designed for 12AX7, don't try it. And biggest improvement to TU-8200 sound comes from swapping out 12AU7 for 12BH7 or better yet E80CC. Read up on it in this thread, don't just do it because those tubes have twice as big plates as 12AU7 and require more heat to stimulate emissions over larger cathode.
> 
> ...



I will keep that under advisement. I just ordered the EL34 to give a listen. Given reintroduction of 300B I may build 8600 just because of the cage to protect tubes.  I am using a rack with 8U locking door to keep my daughter out.


----------



## dawktah2

New EL34 tubes arrived today. First hour can describe sound as a shift to the right towards higher frequencies. I'll give update after burn in.

Tube glass has blue tint.


----------



## dawktah2

Hello All,

Need help troubleshooting. Just noticed I hear a crackle sound in my right ear when nothing is playing. Comes and goes, I still hear the sound when I have no source connected.

Will try switching tubes but was hoping someone could give me an idea if that is a tube thing is a component thing.

--Chris


----------



## vkung

IF NOT TUBE SET ISSUE, PLS CHECK YOUR SOLDERING POINTS


----------



## dawktah2

Swapped driver tubes and crackle sound stays on the right, waiting for cool down to swap signal tubes.


----------



## dawktah2

Degg Nabbitt! Switched the signal tubes and it's still crackling on the right. One other thing I noticed is I can still hear it with volume all the way down. It wasn't doing this before today.


----------



## vkung

check  your soldering points...


----------



## dawktah2

Found the problem, will not reassemble until I can get help as to potential causes since I wasn't light on solder here. I think I may have taken a picture during initial assembly.


----------



## dawktah2 (May 1, 2018)

Bingo! Found pic when I was switching caps, was burning off then...???


----------



## JayKay47

Solder joint was bad, pin and pad weren't bonded


----------



## dawktah2 (May 3, 2018)

Soldered it down on the May 1st, have been listening every evening, noise is beginning to come back. Very low now. Took pic afterwards.

Board was pretty badly burned, cleaned contact, then soldered.


----------



## fide

Hello all,
Dimu wrote about some upgrade of Elekit 8200 for using tubes E80CC. What did he tell about?

Thank you for advice.


----------



## ctrlm

I just pulled the trigger on a fully built unit after a brief audition, it will be my first foray into tube amps. After doing a lot of homework I decided on the Elekit due to this thread and the brand is handled by a local amp builder/repairer, so I have someone to fall back on with potential issues. I won't be cranking her up until I get home tonight. I've already ordered a pair of KT88s to try as well.

My audition was on the Ultra Linear setting. I have no intention of hooking up speakers, it will be headphone only duties. My headphones are Senn HD600 & HD650.

I was wondering which mode people were using based on experience - Ultra-linear, Triode, or Pentode?


----------



## JayKay47

ctrlm said:


> I just pulled the trigger on a fully built unit after a brief audition, it will be my first foray into tube amps. After doing a lot of homework I decided on the Elekit due to this thread and the brand is handled by a local amp builder/repairer, so I have someone to fall back on with potential issues. I won't be cranking her up until I get home tonight. I've already ordered a pair of KT88s to try as well.
> 
> My audition was on the Ultra Linear setting. I have no intention of hooking up speakers, it will be headphone only duties. My headphones are Senn HD600 & HD650.
> 
> I was wondering which mode people were using based on experience - Ultra-linear, Triode, or Pentode?



I started out with Ultra Linear, then changed over to Triode, and that is where it stays now. I feel the vocals are a little more well delivered in Triode vs UL, albeit with a little less authority in the bass department.


----------



## dawktah2

I'm a new build and I am using pentode for now.  I want to get used to I guess I could call it the unmodified setting.  Is that a way to describe it?


----------



## dawktah2

Grumble...

Crackle in right ear is coming back. Will open this weekend.


----------



## Effusion (May 17, 2018)

@fide I wish I could help directly, however I haven't done the mods that @Dimu has to allow for those tube types.  If you search this thread, you'll probably get a really good idea, or you could just send him a pm to find out more specifics.

@ctrlm, very cool, congrats on the amp and welcome to the club!

As far as output mode, it is probably best to try out each one in the end, to see what works best for you and your system.  Personally, I prefer Triode with headphones, at least more than Ultra-Linear overall, but this also depends on the tube types you are running, as I prefer EL34s in UL.  To me and with headphones instead of speakers, Triode gives me a bit more fullness/bloom, better soundstage, and a more relaxed/natural presentation, while UL is quite good in the highs, has great drive/punch, and overall higher gain.  I have yet to really try the Pentode mode, was planning to do some testing weeks ago, but got caught up in other stuff, so I'll report back my impressions of this mode once I do.  However, remember that each mode needs to burn-in a bit, in order to settle in, etc., so give each some time, like 20 hours or so, before deciding which mode you want to keep it in mainly.

Also, were the KT88s new production?  Such as the Gold Lion or Psvane types?  Just curious, I haven't tried either personally, but I've heard them at different events and in other 8200 units.  I've liked the Psvane, however one amp running the new issue cheaper Gold Lions seemed too thin and a bit bright for my general tastes overall, but it could have been something other than the tubes in the chain causing this.

Cheers on the purchase!

EDIT:  Just wanted to caution you when changing output mode types in the 8200.  It is recommended to let the amp sit for 10 minutes unplugged before removing the case and changing the jumpers, etc.  Just wouldn't want you to do any damage to it while testing out the modes, etc.


----------



## ctrlm

Thanks for the feedback guys! The KT88s are new production.

Unfortunately my unit has a 50/60Hz low level hum that is unaffected by the volume control. You can't hear it outside the unit, only through the headphones. I'm not sure if this is a DC offset issue or something amiss in the amp itself? So it looks it's going back to the dealer to be looked at next week.


----------



## ctrlm

I have a question about the volume level. It seems that 7:30/8:00 is fine for normal listening and 9:00 is very loud and distorted. Is this right? It seems strange that it would be this way with so much not being used.


----------



## Effusion

Not sure about the hum, as it could be a lot of different things, but it sounds like a ground hum from your description.  So, you may want to try swapping out the tubes to see if it might be one of them causing any issues.  You mentioned the extra set of KT-88s, but do you also have a different set of 12au7s as well?  In my experience with the amp, sometimes the power tubes will hum and the signal tubes will hiss if they have a problem, so maybe try the stock again to see if it goes away?

Yeah, the 8200 has a ton of power!  Just slightly below 9:00 is where I generally keep mine and even lower if it is loud/fast music in general as well, around 8:00.  Several owners here have swapped out the pot for really good aftermarket options and have also put in resisters to get more movement control out of the pot.  Maybe one of the users that did will respond, but you can also search this thread for some different options that have worked for others.  I still use the stock option, but I am mindful of the extreme gain, especially when someone is trying it out for the first time and isn't familiar with the amp.  I had a buddy that jumped on it during a meet without talking to me first, plugged in his HD800, put the pot to 12:00 and then hit play... wow was he surprised!!


----------



## ctrlm (May 18, 2018)

Effusion said:


> Not sure about the hum, as it could be a lot of different things, but it sounds like a ground hum from your description.  So, you may want to try swapping out the tubes to see if it might be one of them causing any issues.  You mentioned the extra set of KT-88s, but do you also have a different set of 12au7s as well?  In my experience with the amp, sometimes the power tubes will hum and the signal tubes will hiss if they have a problem, so maybe try the stock again to see if it goes away?
> 
> Yeah, the 8200 has a ton of power!  Just slightly below 9:00 is where I generally keep mine and even lower if it is loud/fast music in general as well, around 8:00.  Several owners here have swapped out the pot for really good aftermarket options and have also put in resisters to get more movement control out of the pot.  Maybe one of the users that did will respond, but you can also search this thread for some different options that have worked for others.  I still use the stock option, but I am mindful of the extreme gain, especially when someone is trying it out for the first time and isn't familiar with the amp.  I had a buddy that jumped on it during a meet without talking to me first, plugged in his HD800, put the pot to 12:00 and then hit play... wow was he surprised!!



I still have the stock tubes in, it will be interesting to see if the new tubes solve the hum problem when they arrive. I have tried a lot of tests to see what could be causing it including:

removing the signal tubes
using a cheater plug briefly to ascertain whether or not it was a ground loop issue
having no inputs connected at all
trying different power outlets around the house
turning off every breaker switch in my home apart from the circuit  powering the amp and unplugging any other appliance still connected to that circuit
In all cases there was no change whatsoever to the hum which makes me fairly confident that it is the amp itself and (hopefully) just the tubes, rather than my mains power or an appliance plugged into it that is causing the problem. I know they are solid state but my Schiit Magni 3 and my old Musical Fidelity M1HPA are dead silent without a hint of hiss or hum.

The extreme gain doesn't bother me as it is still easy to find the right listening level, I just found it curious. It will make sure that I am extra vigilant before listening 

Thanks for your advice, it is very much appreciated!


----------



## Lasollor

Hi guys!

I’ve been lurking in this thread for a very long time, this must be one of the most informative thread around here. 
It was a tremendous help building my Tu-8200 about a year ago, so thank you!
It was my first build ever, I was learning how to solder on the way. 
I did some upgrades later one by one, shamelessly copying Dimu’s build to a degree. (bigger rectifier to use E80CC tubes, volume pot upgrade to TKD, all resistor changed to ARMG, drilled holes for better cooling, Cossor 807 tubes, even hunted down the automative caps too). 

Some of my experiences/failures:

When I’ve tried to put in the bigger 3A rectifier, I messed up something, the amp flashed and smelled funny and never turned on again. I had to send it to Elekit, they replaced the transformer and redone some solderjoints. When I got the amp back I had low level hum I didn’t have before. I settled down on a 2A version witch is the same size as the original and it works well with the E80CC tubes. It was cheap, but I had to buy like 50 because that was the smallest available amount.
Since the upgrade I only use the E80CC Valvo tubes, they sound similar to the Amperex 12au7 in tone but drive the output tubes with more authority. Downside for headphone listeners is that they have more gain. So if you already have too much gain, you should keep this in mind. I use Roon with -18db headroom, but 9 o’clock is about maximum I can go with the volume with my HD800 or HD650.
I tried to get rid of the hum in million ways, but nothing helped. Until two months ago, when I finally replaced the volume pot and reheated some solder joints the hum disappeared from the left channel.  Then I reheated most joints in the right channel too and no more hum.
When I ordered the Amtrans ARMG resistors I didn’t noticed that they were not naked, which means the resistors arrived were 3 times bigger and it took a lot of time to find a way to fit them in. (And had to rearrange them later to fit in the volume pot.)
I wanted to use triode mode a couple of times to lower the gain, but it always sounded very off so I went back to UL every time. I didn’t give it time to burn in though so I might try it again.
The E80CC tube with GE 6L6GC and  Philips 7581a power tubes in UL mode has way too much bass. I could enjoy this pairing. The 807 tubes are perfect with the E80CC. (the Sylvania 807s I have sounds good too, more similar to the Cossor tubes than not).
The amp’s chassis and volume knob got very hot in the Japanese summer. After drilling some holes to get the air flow and using 807 tubes the chassis is only lukewarm even after 5 hours.
For some reason the left driver tube socket rattles when I tap on the chassis. I couldn’t figure out this one yet.
Cheap tube socket savers made the tubes rattle, better ones are silent.
It seems to me that after replacing the pot with a TKD 2CP-601 50k pot, I have even more gain (or it might be just more clarity) than before.
The Schiit Saga I have is not transparent enough to use it as a volume controll with the Tu-8200 and HD800/HD650, they loose some clarity and dynamics. It works ok with speakers.
The gain switch on the back seems to effect the headphone out too. I suppose the higher gain applies less feedback, so it has more distortion, is that right?


----------



## Dimu

fide said:


> Hello all,
> Dimu wrote about some upgrade of Elekit 8200 for using tubes E80CC. What did he tell about?
> 
> Thank you for advice.



All information is in this thread, repeated several times actually. It is related to heater current budget of the amp relative to elevated requirements of E80CC or 12BH7.


----------



## Dimu

ctrlm said:


> I was wondering which mode people were using based on experience - Ultra-linear, Triode, or Pentode?



No need to overthink this. Just listen to music 
My amp is set in ultra-linear as it feeds speakers most of the time. Good tubes will make a bigger difference than switching output topology.


----------



## Dimu

Lasollor said:


> I did some upgrades later one by one, shamelessly copying Dimu’s build to a degree. (bigger rectifier to use E80CC tubes, volume pot upgrade to TKD, all resistor changed to ARMG, drilled holes for better cooling, Cossor 807 tubes, even hunted down the automative caps too).



Pictures or did not happen 

Please feel free to borrow ideas, improve on them and share results!


----------



## Dimu

Lasollor said:


> When I’ve tried to put in the bigger 3A rectifier, I messed up something, the amp flashed and smelled funny and never turned on again.



I have not done anything like this with my amp (yet), but have done it with other equipment powered by massive transformer and rectified with huge caps and then had to rebuild vaporized traces in the power supply. A wire hanging out or a careless move with a screwdriver is all it takes to short things. This is why I apply PTC thermistors to all power lines when I design my own stuff. Of course when you replace components that don't fit into allocated space you have even more risk so need to think through both electrical isolation and thermals.


----------



## sunneebear

Dimu said:


> Pictures or did not happen
> 
> Please feel free to borrow ideas, improve on them and share results!



Oh hell no!  Everyone is getting a cut.  I'm not saying it's a pyramid scheme, but it's a pyramid scheme.


----------



## Dimu

sunneebear said:


> Oh hell no!  Everyone is getting a cut.  I'm not saying it's a pyramid scheme, but it's a pyramid scheme.



It sounds like you need to get busy rolling some tubes... how long has it been since your last roll? 
I've been abstinent for a few months, already feeling itch creeping up.


----------



## sunneebear

Dimu said:


> It sounds like you need to get busy rolling some tubes... how long has it been since your last roll?
> I've been abstinent for a few months, already feeling itch creeping up.



Mine has been MIA for a couple of months now.  
On loan to my brother who just bought a pair of Zu Omens.


----------



## Lasollor

Dimu said:


> Pictures or did not happen
> 
> Please feel free to borrow ideas, improve on them and share results!



Unfortunetely I forgot to took pictures last time I opened up the amp, but I have some (bad) pictures from before:


----------



## Lasollor

Dimu said:


> I have not done anything like this with my amp (yet), but have done it with other equipment powered by massive transformer and rectified with huge caps and then had to rebuild vaporized traces in the power supply. A wire hanging out or a careless move with a screwdriver is all it takes to short things. This is why I apply PTC thermistors to all power lines when I design my own stuff. Of course when you replace components that don't fit into allocated space you have even more risk so need to think through both electrical isolation and thermals.


I don’t know anything about electronics or how amps work and sometimes I wonder where did I find the courage to try to build an amp like this. (I think this thread was the main reason) I even had to but the screwdrivers and every tool new just for this project. So I messed it up a few times. Then read about it and made it right. I’ve learned a lot on the way and it was really fun.


----------



## Dimu

Lasollor said:


> I don’t know anything about electronics or how amps work and sometimes I wonder where did I find the courage to try to build an amp like this. (I think this thread was the main reason) I even had to but the screwdrivers and every tool new just for this project. So I messed it up a few times. Then read about it and made it right. I’ve learned a lot on the way and it was really fun.



In that case make sure you stay away from those orange wires hanging off the output tubes- there is more than enough voltage there to zap your heart for good. And keep kids away if you have any around.


----------



## Dimu

Dimu said:


> Good tubes will make a bigger difference than switching output topology.



Speaking of output tubes- swapped EL12 spez back in after long time with TT21. Both are awesome but I had impression I liked TT21 sound better right after I pulled them. Having said that I had a bit of similar feel when I swapped EL12 spez out for TT21. Spent couple hours listening to different records and swapping tubes and there are situations where EL12 spez sounds better than TT21. TT21 sounds great in that case, but EL12 spez sounds really special and engaging. I guess EL12 spez is going back into the amp. 

Been checking on tube supply recently. E80CC is probably never going to be plentiful again. They are still around but low quantities and expensive. Same story wtih EL12 spez- price has doubled in a year and supply is very low. TungSol 6550 and GEC KT88 are nowhere to be found as are 211/845 tubes that I wanted to find for a different amp project. I already have lifetime supply of NOS tubes for this amp but I will definitely grab more tubes when I find some reasonably priced ones.


----------



## Lasollor

Dimu said:


> In that case make sure you stay away from those orange wires hanging off the output tubes- there is more than enough voltage there to zap your heart for good. And keep kids away if you have any around.


I’ve read that a couple of times but thanks for reminding me again. I do plan to build some kind of cage for it. I try to be as careful as I can be, I made a cable with a big resistor to discharge the caps every time I open the amp etc.

I picked up 6 pairs of Valvo E80CC for cheap when I had the chance. How long these tubes would last in this amp in your experience?


----------



## Dimu

This is how far Fluke pen picks up- it is rated from 90V and it is designed to be inserted into an outlet to touch the wire...


----------



## Dimu

Lasollor said:


> I picked up 6 pairs of Valvo E80CC for cheap when I had the chance. How long these tubes would last in this amp in your experience?



If those are new you are set for life! They are formally rated at 10000 hours. Even if they last half that long you have multiple decades of daily enjoyment ahead of you 

caps will have to be replaced many time before you wear out 6 pairs of E80CC. Many caps are rated at 1000 hours only. Even really good ones are 3000 hours. So you will need to replace caps at least 20 times before you have to buy more E80CC


----------



## Effusion

Welcome to the club @Lasollor!

Congrats on tackling this kit for your first project, impressive!  It sounds like you've learned a lot while building/tweaking it, and I know while it must have been very frustrating at times, it was fun and rewarding in the end.  I'm glad the thread helped so much too!

Wow, you've done a ton to it!  Thanks for sharing all your experiences... now you, in addition to @Dimu, are making me want to rip the top off my unit and go to town as well.  Some nice E80CCs sound like a good idea to me right about now!  Just got to go for it in the end right... I've always thought about a separate unit to drive some proper single drivers in a different area, so maybe I'll just start fresh and keep this one the way it is eventually.

I also wish the availability/prices of good NOS weren't such big issues for many tube types as well... we just need more quality new production manufacturers to figure out where they are going wrong currently, make them as good or even better than old stock, and produce a ton of variety!  Wishful thinking I know, but at some point the demand will be too high to just be ignored any longer, plus with what some are willing to pay currently, prices would be there as well to justify doing it right.  Really just too bad it is so hard to manufacture them correctly and that with the dying of the art decades ago, also soon comes the dying of the knowledge in a way as well.  As a side note, I recently meet a woman owner of a piano show house and she mentioned her son makes all the tubes for his amps at home in his garage... sounded crazy to me at the time, but now I want to learn more!

Anyway, cheers to the amp and thanks for posting!


----------



## Sir Gaben

Elrog are suposed to be a good quality brand, but they manufacture 211/845 and 300bs only at 1500 dollar a pair.


----------



## dawktah2

Being a newbie, I grasp concept of "tube rolling," but do you have let tubes cool first or just turn unit off so there's no power?


----------



## Sir Gaben

dawktah2 said:


> Being a newbie, I grasp concept of "tube rolling," but do you have let tubes cool first or just turn unit off so there's no power?


I usually let the tubes cool off for 5 min or so before I switch tubes.


----------



## Dimu

I pull the tubes out as soon as I can hold them. When tubes are in a big socket that does not get hot I pull the tubes immediately after powering off the amp. For tubes that have no cool base I let them cool down, unless I am impatient in which case one of my socks comes off to get slipped onto my hand to grab a hot tube


----------



## sunneebear

Dimu said:


> I pull the tubes out as soon as I can hold them. When tubes are in a big socket that does not get hot I pull the tubes immediately after powering off the amp. For tubes that have no cool base I let them cool down, unless I am impatient in which case one of my socks comes off to get slipped onto my hand to grab a hot tube



Yeah I do the same.  I just give it about 10 seconds after powering off just in case something needs to discharge.  After that I use a microfiber cloth that is used to clean the tubes to pull them out and put them aside to cool.


----------



## dawktah2 (Jun 3, 2018)

Ok, resoldered the connector in post #896 in this thread. I disassembled since crackling was getting worse and this is what I found.


----------



## dawktah2

So I removed all the prior solder and cleaned the pad. Fluxed the pad applied solder and desoldered it again.  Recleaned it and applied flux second pic.  Then resoldered third pic.


 



 

 

What component(s) could have been damaged by the initial pad going unsoldered that I should consider replacing?  I will post again in about an hour if crackling is still present.  Unit has been warming up for about 30 minutes.

--Chris


----------



## dawktah2

Crackle all but gone can still hear very very slight.  Any ideas?


----------



## Dimu

Been enjoying vinyl from AT440MLb cartridge directly to TU-8500 preamp. Sounds better than Gungnir Multibit, at least I have this impression. Ordered Nagaoka MP-200 to compare. This is getting unhealthy- rolling tubes and cartridges at the same time 

There is some hum in the phono section of my TU-8500, will have to open it up and do some investigating. Could be those Bursons that I inserted in there, but I hope that's not the case.


----------



## Dimu

dawktah2 said:


> Crackle all but gone can still hear very very slight.  Any ideas?



What are you soldering with? Unleaded crap? I used lead with silver on mine and made sure everything was heated properly. No issues with joints. Unleaded solder is garbage.


----------



## Sir Gaben

Dimu said:


> Been enjoying vinyl from AT440MLb cartridge directly to TU-8500 preamp. Sounds better than Gungnir Multibit, at least I have this impression. Ordered Nagaoka MP-200 to compare. This is getting unhealthy- rolling tubes and cartridges at the same time
> 
> There is some hum in the phono section of my TU-8500, will have to open it up and do some investigating. Could be those Bursons that I inserted in there, but I hope that's not the case.


What turntable do you have?


----------



## Dimu

AT-LP1240, nothing fancy, just a solid turntable


----------



## dawktah2 (Jun 5, 2018)

Dimu said:


> What are you soldering with? Unleaded crap? I used lead with silver on mine and made sure everything was heated properly. No issues with joints. Unleaded solder is garbage.



I used Kester lead rosin solder. 

I switched input cable L <--> R and tubes L <--> R, crackle remained on the right.


----------



## Lasollor

Dimu said:


> If those are new you are set for life! They are formally rated at 10000 hours. Even if they last half that long you have multiple decades of daily enjoyment ahead of you
> 
> caps will have to be replaced many time before you wear out 6 pairs of E80CC. Many caps are rated at 1000 hours only. Even really good ones are 3000 hours. So you will need to replace caps at least 20 times before you have to buy more E80CC


Good to know! Thanks.

About my rattling E80CCs:
I’ve got a good deal on two used pairs of tube dampers in a local store. I hoped it would solve my problem with the driver tubes rattling a little.
It turned out that the tubemonger socket savers made the rattle way worse. After removing the sockets the rattle became almost non existent. And the damper’s mass is just enough to eliminate the remaining rattle. It’s not the best solution and I don’t like the color, but it was almost free and works for now.

Picked up some Toshiba UY-807A tubes recently so did some tube rolling too.
This is an interesting tube.
There is not much about it in english on the internet, but I’ve found some information in japanese: (neither english nor japanese are my native languages so some information might lost in translation):

“Apparently a researcher called Eizaburo Nishibori who later lead the first Japanese Antartic Research Expedition was working in the Vacium tube research center of Toshiba Denpa (They were mainly working on tanks and airplanes) said somewhere, that the Japanese army wanted to equip their tanks with an ultra-short wave (under 10m) telephone so they ordered the research center to quickly develop and manufacture a vacume tube which is capable of very high frequency. The Japanese-Sino war just started so they had to act fast. At the time the frequency limit of the bakelite base vacuum tubes was 20 Mc/s. They developed a new vacuuming method and used a steel base for shielding. This was the birth of the UY807a tube which was capable producing smaller than 10m ultra-short waves (40MC/s) and which was only made in Japan and only for a very short time.”

It is a bright tube, the brightest 807 tube I’ve heard with very upfront vocals. It makes the HD650 sound similar to my Stax L700.


----------



## Dimu

Dimu said:


> There is some hum in the phono section of my TU-8500, will have to open it up and do some investigating. Could be those Bursons that I inserted in there, but I hope that's not the case.



Yep, Bursons had to go. And put in very short cables. No audible hum unless I turn up volume. Next step is reducing gain in both stages of phono amp and sticking in four LME49990 in there- waiting for adapters.


----------



## Dimu

Dropped gain of both phono amp stages by half and added 10 and 0.1 ceramic caps to op amp bypass electrolytes. No more audible hum even when volume is turned up all the way. Now tubes do more amplification than before this mod. Bursons aren't behaving though- instant hum when I stick them in. So LME49990 project is on. Will have to hack some local bypass for those because there is no ground on the adapter.


----------



## Lasollor

I have a question. What resistor value should I use in R3 and R4 if I want to reduce the gain of the tu-8200?


----------



## Dimu

Lasollor said:


> I have a question. What resistor value should I use in R3 and R4 if I want to reduce the gain of the tu-8200?



why would you want to reduce gain of the whole amp? do you have signal generator and oscilloscope to measure what you are doing? Increasing NFB will bring down gain but it is well balanced as it is.


----------



## Lasollor

Dimu said:


> why would you want to reduce gain of the whole amp? do you have signal generator and oscilloscope to measure what you are doing? Increasing NFB will bring down gain but it is well balanced as it is.


Actually it would be fine to reduce only the gain of the headphone out. Is there a better way to do that? I have way too much gain.


----------



## Dimu

Lasollor said:


> Actually it would be fine to reduce only the gain of the headphone out. Is there a better way to do that? I have way too much gain.



Just attenuate input signal more, no need to mess with gain.


----------



## Lasollor

Dimu said:


> Just attenuate input signal more, no need to mess with gain.


Yeah it maybe doesn’t worth the effort. I use about -18db digital attenuation in software and even with that I’ve got about 10-20% usable volume on the pot.
Roon does the DSP in 64bit floating and then converts it back to 24 bit before output. (My Yggdrasil can’t do 32bit)
Most of my music is 16bit 44.1k so I don’t loose any bits, but with 24 bit high res files 18db (3bit) digital attenuation means that I loose some resolution. Of course I’m not going to loose any sleep over it, most likely it’s inaudible. But I don’t want to increase it more than that.
Analogue preamps all had audible effect so I gave up on them. I just wanted a little more range on the volume pot.


----------



## ctrlm

Whilst it is now less audible, I still have a faint consistent hum in my pre-assembled unit that is not affected by volume. I have it in Triode mode and it is slightly louder in Pentode & UL.

That's after the guy I bought it from looked it over and installed Mundorf aluminium oil caps etc. and changed the resistors at the headphone input. 

I think I'll take it apart next weekend and give it all the once over to see if there is something obvious such as a bad solder point or something?


----------



## Dimu

I would recommend feeding your files directly into Yggdrasil without any DSP. With each conversion you are distorting sound. If you convert to 64 bit, then attenuate, then convert to 24 you've done three bad things to your signal. And then one more- you aren't using all of the bits in your Yggdrasil when you do that- that's a shame because Yaggdrasil has those expensive chips to have the extra bits. -18dB is insane- you really are chopping dynamic range of your DAC. So throw away all DSP and let Yggdrasil play your source files. And you simply need a different pot in your amp if you want to have different pot volume range.


----------



## Dimu

ctrlm said:


> I think I'll take it apart next weekend and give it all the once over to see if there is something obvious such as a bad solder point or something?



Bad solder joints aren't visible, often not even under microscope. That's why welders test their work using xrays. The only way to deal with a suspected cold joint is to reheat properly every joint- this will reflow the solder. Sometimes the problem is with surface prep in which case even reheating won't help- need to clean up and remove whatever is preventing solder from joining.


----------



## ctrlm

Dimu said:


> Bad solder joints aren't visible, often not even under microscope. That's why welders test their work using xrays. The only way to deal with a suspected cold joint is to reheat properly every joint- this will reflow the solder. Sometimes the problem is with surface prep in which case even reheating won't help- need to clean up and remove whatever is preventing solder from joining.



Yeah - I was afraid of that


----------



## dawktah2

Dimu said:


> Bad solder joints aren't visible, often not even under microscope. That's why welders test their work using xrays. The only way to deal with a suspected cold joint is to reheat properly every joint- this will reflow the solder. Sometimes the problem is with surface prep in which case even reheating won't help- need to clean up and remove whatever is preventing solder from joining.



I did this and still have crackle I posted about earlier. I am looking for troubleshooting help, now.


----------



## Dimu

First experiment- JFET input with OPA1642. Sounds much better, finally I like the sound I get out of vinyl. Really noticeable improvement. The next step will be OPA1641/LME49990 hybrid where OPA1641 handles initial pickup from the cartridge and LME49990 drives the tube in the preamp. Might even play with gain between two stages to shift more gain towards LME49990. 

I like TU8500 a lot after the updates that I did, but there is a bit of topology trouble as left channel picks up more hum than the right channel. Not audible, but visible with oscilloscope.


----------



## Dimu

Had a musician friend visit me yesterday. Played his studio-recorded tracks via Gungnir Multibit and TU8500/TU8200 on LS50. He liked it a lot, said reproduction was excellent including both voice and drums. He was surprised by base actually. The tubes I currently have are Mullard 12AT7 in TU8500 and Dutch E80CC with Telefunken EL12 spez in TU8200.


----------



## Dimu

And now I am breaking in this beauty, arrived today from Japan. Tube rolling, op amp rolling, cartridge rolling... I guess speaker rolling is next


----------



## Dimu

I think I am finally happy. Built a JFET/bipolar hybrid today- input stage OPA1641 at half gain and driver stage LME49990 at full gain. Hum is much more controlled than even with OPA1642 at half gain. Sounds great with Nagaoka MP-200, I like it better than OPA1642, which was in turn much better than anything else I tried before, with Burson being the worst offender due to horrible hum. I might as well stop here. The only other idea is to try dual LME49990 but that might get more noisy on the input end.

I think this would be my recommendation for anybody looking to spin vinyl into TU8200- build a TU8500 with Mundorf caps, TDK pot, improved bypass for opamps, halved gain for the input stage and these babies:


----------



## Dimu

Tried dual LME49990. Sound is awesome. As expected noise is slightly higher- at full amplification of TU-8200 I measured 60 dB at the speaker for dual LME49990 and 59 dB for hybrid OPA1641/LME49990 version (first stage gain is still suppressed to 50%). I think I will stick these into spectrum analyzer to measure actual difference. I now have five different opamps that I can compare- the original opamp, the upgrade recommended by Victor, OPA1642, OPA1641/LME49990 and LME49990/LME49990. With two channels in the amp that's 10 measurements- sounds like a fun project...


----------



## Effusion

@Dimu very cool!  I'm a big vinyl fan as well and after following everything you recently did with your rig, I may have to do something similar to mine in the future too.  I've been down the crazy opamp road before in other equipment and I would roll quite a few in the past, so I know how much of a difference they can make to the sound in the end and how satisfying it is to finally find that magic one.

Also, that MP-200h looks amazing!  I'm sure it sounds just as good as it looks too.  There is just so much to getting great sound out of vinyl, from the cartridge, to the table, to the phono preamp, and beyond.  I always get a bit of a chuckle when vinyl newbies initially think it is as simple as their digital rigs and then find out how complex it truly can be.  In the end though, vinyl offers something that digital audio really just can't, not that it is superior in anyway, just different.  I actually prefer certain recordings on vinyl versus digital and even with a few, when I hear them digitally now, I can't help it, I just think about how they sound different on vinyl while listening digitally.

The crazy thing is how vinyl has been resurrected in recent years as CD sales have fallen off the map... while digital downloads/streaming is so much quicker/easier, there is a disconnect from the physical media that I believe can create a hidden void in one's psyche.  There is just something to getting a new record, examining the artwork/cover, feeling it in your hands, and the physical action of putting a needle to it.  Then there is always the spontaneous nature of it, the random pops/crackle, etc. add to the overall presence of the sound.  The great thing is how many new albums offer digital downloads with the vinyl versions, so one can now justify the extra cost of the record.  Also, some of my favorite genres on vinyl are ambient, classical, and jazz, as it just seems to add so much extra character and nuance to the sound, creating an environment where the music just seems more real or in the moment.  Now, I do know a lot of guys who stay away from vinyl like it is the plague, but that is really just because they burnt-out on it back in the day and it is just not as simple as digital music or they just have never been exposed to it properly, but I think they are sometimes missing the point.  It's not that we think vinyl is superior or even equal necessarily, although with some recordings it actually is, but different in such a way that we feel closer to the music in general when we experience it.

Keep letting us all know how it goes!


----------



## Dimu

Well here is a DUH moment- went poking into those opamps with oscilloscope and could not figure out why the output is different between the two channels until I noticed that the channels are wired upside down- right channel has second op amp as input stage while the left has the first op amp as the input stage. So I need to flip op amps in one of my hybrids and I have to watch which one I put into which channel... I kept looking just at the left channel on the schematic assuming that they are symmetrical. Turns out, for some funny reason, they are not.


----------



## Dimu

Regarding opamps- waiting for SOIC AD797 to throw into the mix. Will also flip one of the hybrid OPA1641/LME49990 at the same time.

I looked into RIAA equalization filter to see where it is at. Shifted balance point using the additional resistor network at the top of the board and tuned one of the caps with additional polysterene caps (bottom of the board). This aligned the filter component measurements to theoretical calculations. Then measured frequency response with LME49990 relative to RIAA curve. At the output of TU8500 top end is within 0.1 dB of ideal levels (the last column in the measurements table). Bottom end is suppressed though, will need to tweak that further and re-test. And I want to play with noise- I want the phono amp to be quieter.


----------



## Dimu

So I cleaned out phono section today:



 
then soldered back better metal film resistors and low pass filter caps with polypropylene dialectric. Dropped input impedance to 47k. 


 
Back is now cleaner too- only bypass caps remain on the back side:


 
Running frequency response traces now on the whole unit at max volume with 3x gain switch and MM mode switch.


----------



## Dimu

Traces confirmed what I measured earlier. Here are left and right channels below 1 kHz (100 Hz per division)- there should have been a bit more drop- supposed to be 19.35 dB:


 


 

These are left and right from 1 kHz to 21 kHz- perfect 20 dB drop:



 





These were measured across whole TU-8500- from phono input to the output, at max volume setting. Channels track each other perfectly both below and above 1 kHz- that is because I used highly matched components on both sides.


----------



## Dimu

Results of noise measurement on op-amps below. Measured using SPL1000 at the left speaker with TU-8500 and TU-8200 volume turned up to the max setting. 

original JRC 2068 DD - 54 dB
OPA 2227P - 58.5 dB
OPA1642 - 56 dB
AD797/AD797 - 55.5 dB
OPA1641/LME49990 - 55 dB
LME49990/OPA1641 - 59 dB (this is simply flipped installation of hybrid opamps between left and right channels)
LME49990/LME49990 - 59 dB

Here is what I think based on this:

1. the original op amp has the lowest noise- that is a surprise!
2. predictably LME49990 in the first stage leads to high noise due to high current noise of bipolar input.
3. AD797 has very respectable result. 
4. OPA1642 is not great likely because of the second stage noise (voltage noise due to JFET architecture).
5. OPA1641/LME49990 has the lowest noise of high quality opamps. This is what I expected, except JRC 2068 DD is somehow quieter...

Based on these measurements I decided to choose between AD797 and OPA1641/LME49990 hybrid. So I did a listen test. And I liked the hybrid better. Sound is more dynamic, more punchy. This is subjective of course.

So I am leaving the hybrid in there. First JFET stage has half the gain of the second bipolar stage (I put 4.7K resistor instead of 10K in the feedback loop of the first stage). Basically first stage picks up MM cartridge signal and drives the RIAA filter. Actual amplification is done by LME49990 in the second stage. TU-8200 tubes add just 3x gain on top, followed by two driver stages and output stage of TU-8200.

Listening to this whole setup as I am typing it- sounds awesome!
If you want turntable in your future grab a TU-8500 while they still make these kits!


----------



## Dimu

This is to document how hybrid opamp is installed with mixed up channels. The picture is upside down because it is taken from the back of the case- left channel is on the right. The top op amp is #1 and the bottom is #2 in these adapters. In the left channel (right on the picture) there is a stripe- this is OPA1641. The right channel has top opamp with first pin marked with a dot- this is LME49990.


----------



## Dimu

I discovered today that EL12 spez excites in UL mode (likely capacitances in the tube with inductance of the portion of the output transformer) and oscillates at 400 kHz with fairly significant amplitudes. This phenomenon is volume-dependent, it does not happen at low volume but occurs sharply past certain threshold. So if anybody wants to run those tubes make sure to flip to triode mode. This eliminates inductance from the second grid.


----------



## Dimu

DO NOT TRY THIS AT HOME 

well, you decide if you want to try this, but you've been warned 
seriously, this is not endorsed by Elekit in any way, they recommend against doing this.

I wanted to try to drive a big 8 Ohm speaker and TU8200 did not sound too good. So I converted it into a monoblock. Paralleled inputs, paralleled outputs, switched to 8Ohm load mode (this is important for several reasons, including the fact that this provides global feedback encompassing both channels of the amp at the same time via that blue cable in the picture below). Used oscilloscope to monitor amp output and so far so good. It is not about louder output, it is about improving damping and headroom. Tested with GEC TT21 driven by E80CC it sounds AWESOME even on a single speaker. UL mode seems to sound better than triode mode in this setup. I think I am building the second amp to have cute monoblocks with amazing sound, and still be able to flip into headphone mode at any time! Except now I need twice as many tubes 

I keep getting amazed by this little gem of an amp!


----------



## dawktah2

I am trying to find the source of noise in my unit.  I have a PS Audio Dectect power conditioner and with nothing connected, input device(s) or cables I can hear our HVAC units when they kick on.  Are valves more susceptible to this type of noise?  Its a buzzing that coincides with the quick dimming of the lights.  The Dectect is plugged into a UPS.  I am planning on calling PS Audio tomorrow with as much information as I can. Synology 416play NAS is also plugged in and is the music source. I am going to listen with only the Elekit plugged into Dectect but I don't think it will matter along with bypassing UPS.

Any ideas?


----------



## Dimu

This is not about valves and not about power source. It is electromagnetic interference that is picked up by your system and amplified by the amp. You can reduce energy levels (e.g. increase distance to the source of interference) or improve shielding (this is not an easy task). Could also be some kind of defect in your amp that makes it more susceptible to interference.



dawktah2 said:


> I am trying to find the source of noise in my unit.  I have a PS Audio Dectect power conditioner and with nothing connected, input device(s) or cables I can hear our HVAC units when they kick on.  Are valves more susceptible to this type of noise?  Its a buzzing that coincides with the quick dimming of the lights.  The Dectect is plugged into a UPS.  I am planning on calling PS Audio tomorrow with as much information as I can. Synology 416play NAS is also plugged in and is the music source. I am going to listen with only the Elekit plugged into Dectect but I don't think it will matter along with bypassing UPS.
> 
> Any ideas?


----------



## dawktah2

Dimu said:


> This is not about valves and not about power source. It is electromagnetic interference that is picked up by your system and amplified by the amp. You can reduce energy levels (e.g. increase distance to the source of interference) or improve shielding (this is not an easy task). Could also be some kind of defect in your amp that makes it more susceptible to interference.



Mmm, I think I'll build a mini pseudo Faraday cage (two cables would be sticking out) and see if this works.


----------



## jerick70

I'm really interested in the TU-8200.  I love building my own gear. How does this amp compare to Woo gear? How does it compare to other tube gear? 

I've owned the WA22 and WA5. The WA5 was awesome and the WA22 was just so so.


----------



## Lasollor

jerick70 said:


> I'm really interested in the TU-8200.  I love building my own gear. How does this amp compare to Woo gear? How does it compare to other tube gear?
> 
> I've owned the WA22 and WA5. The WA5 was awesome and the WA22 was just so so.



I haven’t heard the WA5 or WA22, but I’ve picked up a WA6-SE a few months ago with a WE422A rectifier and Westinghouse 6FD7 tubes in it. It is a very good amp, but directly comparing it to my modded TU-8200 (with Valvo E80CC and Hitachi 807 tubes), it looses in almost every aspect. The Elekit has better clarity, bigger soundstage, tighter bass and the sub bass goes lower. The WA6-SE is a little bit muddy (only in comparison), but it has a softer and sweeter sound to it. The Elekit sounds very different with different tubes, which can be a blessing and a curse and mine is now tuned to my preferences with the HD650. With the same tubes, the HD800 is easier to listen with the WA6-SE, but if I swap the tubes to RCA807, or Cossor 807 then again I prefer the TU-8200. I also have a LFF Paradox planar headphone, and I don’t like these at all with the Woo, TU-8200 is a better match. In the end I’m planning to sell the Woo amp soon, but I’m happy that I could compare the two.


----------



## sunneebear

Also a killer speaker amp too.


----------



## jerick70

sunneebear said:


> Also a killer speaker amp too.


I think it would go well with my Zu Omen IIs.


----------



## jerick70

Now to decide between the TU-8200 and the TU-8600.  The only thing holding me back from the 8600 is the cost of 300b tubes. This is why I sold my WA5, I can't see spending 4x - 5x the cost of the amp on tubes that will end up failing.....


----------



## vkung

Both are good amps. It is DIY.. The most important is your budget and what you want...

EH gold pin is not expensive . It is DIY you can upgrade later to Psavne WE300B or Elrog 300B...


----------



## sunneebear

jerick70 said:


> I think it would go well with my Zu Omen IIs.



My brother has the Omen and tried my TU 8200 with it.  I only had the stock tubes then and he didn't care for the paring.  Too mellow and tubey.


----------



## jerick70

sunneebear said:


> My brother has the Omen and tried my TU 8200 with it.  I only had the stock tubes then and he didn't care for the paring.  Too mellow and tubey.


That's too bad. I guess the TU-8200 is out then. 

Does anyone know how the TU-8600 fairs with the Zu Audio Omen IIs?


----------



## sunneebear

jerick70 said:


> That's too bad. I guess the TU-8200 is out then.
> 
> Does anyone know how the TU-8600 fairs with the Zu Audio Omen IIs?



That's just one person's taste with the stock tubes.  If you have read through this thread then you know that this amp is a virtual chameleon with tube rolling.


----------



## Effusion

Yeah, I wouldn't rule out the 8200, at least not right away.  Different tubes can make a huge difference as well as output modes.  It might have sounded too tubey and mellow to sunneebear because it may have been in Triode mode and thus Ultra-Linear mode may be a better match, as it tends to be with most speakers.  Sunneebear, do you remember what mode it was in at that time?  Even if it was in Ultra-Linear mode, the source and other things may have been attributing to this as well.  Either way, the 8200 gives you a ton of options to tweak the sound to your liking.  If there is one comment I hear most from those that hear my 8200, especially from my buddy who has heard it many times, is that it isn't a crazy tubey sounding amp.  Nothing like the Bottlehead Crack and the like, which while really seductive/smooth, tends to be too bloomy and way too slow for my tastes in general.  My 8200 is just right for my ears and has the attack that other tube amps tend to lack.  Of course, this too is just my opinion and I do have upgrades in it, so it isn't stock.

Regardless, they are both really great amps, although I unfortunately haven't been able to spend as much time with the newer 8600, especially compared to the time I've had with the 8200, since I have never owned a 8600 and have only heard it at RMAF twice.  I will say, that after many years now, I still have no desire to go with any other amps, and I've tried a ton of different ones, including very expensive ones, since owning my 8200.  That is one thing that is great about these amps, as well as other offerings from Elekit, for the price they simply cannot be beat in my experience.

My best recommendation, of course without having much experience with the 8600, would be the 8200, since it is cheaper, smaller, and doesn't require expensive 300Bs, etc.  Actually, one of the big positives in my opinion of the 8200 is the vast amounts of different types of tubes you can use in it, and even though some are very hard to find and expensive, new production are available as well; just lots of options in the end.  With all this said, if you plan to primarily use the amp to drive speakers, the 8600 would probably give you more of what you are wanting ultimately, but if like me, you will primarily use it with headphones and just occasionally or secondarily with speakers, than 8200 may make more sense or if just to get your feet wet within the world of Elekit initially.

Either way they are both great amps in my experience, but continue to let us know if you have questions!


----------



## dawktah2

I've stopped listening to mine since I have the crackle I don't know how to troubleshoot. It's not a tube since swapping L < > R on all tubes had no effect.


----------



## vkung (Dec 27, 2018)

there are only reasons
1. bad tube set or
2. bad soldering points

if it is not the issue from tube set, please check all your soldering points


----------



## Dimu

TU8200 is amazing. It is compact, it is versatile and it sounds really great! And also it is affordable. The base kit should cost more considering what's included and the quality. Yes, it stops being so affordable when all possible upgrades are applied to it. But it is one amazing amp, which is why I bought two kits for myself. It won't last forever, grab it while you can.

I spent some time with TU8340 with Lundahl transformers that Victor was kind enough to loan me to test it with my new big speakers. Then I hooked up TU8200 in parallel also known as "monoblock configuration" (notice- this is neither supported nor recommended by the manufacturer, so don't try this unless you are prepared to face the consequences on your own). And TU8200 with TT21 tubes sounded definitively better to my ears than TU8340 driving a large floor standing speaker. Yes, my TU8200 is probably the most upgraded unit out there (including larger power transformer), but still it fits in the same compact case. TU8340 is huge and heavy, a really well built amp and those Lundahls are great too. So for TU8200 to sound better while driving massive speaker it is amazing!

So yes, this is an amazing amp, that does not stop pleasuring my ears. And I built it myself, that gives me pleasure too! I listen to it every day when I get a chance, sometimes for 8+ hours per day. It is great. And so is TU8500 preamp including its phono section. Listening to this combo right now...

Oh and by the way, this thing will still be awesome long after the latest iPhone turns into obsolete garbage...


----------



## dawktah2

vkung said:


> there are only reasons
> 1. bad tube set or
> 2. bad soldering points
> 
> if it is not the issue from tube set, please check all your soldering points



Not being someone whom has done a lot of critical electronic soldering this check is done how?  Am I to just re-flow all the connections?


----------



## vkung

check and re-solderer each connections.


----------



## Effusion

@Dimu, you are a true madman!  Absolutely amazing what you have been able to do with your 8200(s) over the years... really a testament to the versatility of this little amplifier and what can be accomplished.

If anyone is concerned about the 8200 not being able to get them where they want to be ultimately, all you have to do is look at all the tweaks @Dimu has done, really shows that almost anything is possible with this amp and the truly great sound that can be achieved!


----------



## dawktah2

Spent last two hours fully disassembling the unit, and used my loupes and couldn't visibly see any bad contacts. Re-flowed all the solder and the crackle has gone!

Thanks so much! No clue which one it was...

It's probably my imagination but sounds more powerful, but could be from not listening to it.


----------



## portlandpsu (Jan 1, 2019)

Just finished before new year


----------



## Dimu

portlandpsu said:


> Just finished before new year



I've got the same caps but I did not figure out how to stick them in. Did not like the idea of long wires to avoid picking up noise.


----------



## Dimu

dawktah2 said:


> Spent last two hours fully disassembling the unit, and used my loupes and couldn't visibly see any bad contacts. Re-flowed all the solder and the crackle has gone!
> 
> Thanks so much! No clue which one it was...



Did you use lead-free solder? That stuff is crappy- high melting point and good chance to get cold joints if you are not careful giving each connection point some extra heat time. And overheating components and traces is not healthy. I always use lead, and for Elekit assembly I used lead with silver alloy.


----------



## portlandpsu

If you don't use the long wires, it is no way to stick them in.  However, It was no noise to pick up.  The background is so quiet.


----------



## portlandpsu

I used lead free solder which was Oyaide SS47.  So I use high temp iron (around 370-390 degrees) to solder the component.  It is better to complete soldering the component in 2 seconds.


----------



## dawktah2

Dimu said:


> Did you use lead-free solder? That stuff is crappy- high melting point and good chance to get cold joints if you are not careful giving each connection point some extra heat time. And overheating components and traces is not healthy. I always use lead, and for Elekit assembly I used lead with silver alloy.



I used Kester and a Hakko FX888D.


----------



## JayKay47

@vkung Is it true tha the TU-8200 does not have feedback and that the TU-8600 does have a feedback circut?


----------



## vkung

TU-8200 has feedback circuit 
Tu-8600’s OPT has the 3rd winding. This 3rd winding allows to reduce the overall NFB


----------



## ProfessorC1983

Hi everyone... wanted to say hello, since I bought myself a TU-8200DX from Victor as a Christmas present to myself. Had a lot of fun soldering it together and now I'm waiting for it to fully burn-in. I only have about 15 hours on it, so from everything I've read I know it will only get better from here! Thanks to everyone who has participated in this thread over the years. Reading it was a delight and there's such a wealth of information here about how to customize this amazing product.

Victor talked me into the Mundorf Supreme Silver Gold caps and the Genelex Gold Lion ECC82 tubes, along with the Amtrans resistor upgrades. As for power tubes, it's really a shame the NOS market has dried up... I'm so jealous of you guys that got GE 6L6GC's for $50 a pair back in 2015! Right now they're going for $180/pair on eBay, but I figure I should bite the bullet and pick up a set since they'll soon be gone forever. I want to try the SED Winged C EL34's as well since those will also disappear. I figure I'll have years to enjoy the new-stock tubes which will hopefully get better with time.

I picked up some Senn HD650's as well, which is a divine pairing so far, and I'm also using the Elekit to drive my ELAC Debut B6's. They aren't quite sensitive enough for Triode mode, UL is slightly better, but I think my next investment will be in some high sensitivity floorstanding speakers. I've heard that Tekton Lores are a great option for low-wattage tube amps, but I'd love to hear what <$1000 speakers you guys like specifically for this amp.

I did have a question for the user above who's using the Schiit Saga as a pre-amp for the Elekit, as I'm eager to use this combination as well. (I'll use the setup for TV watching in addition to digital music and vinyl, so having a remote volume control is important.) Did you find the reduced clarity occurred in the Saga's passive or active tube buffer mode, or both? I plan to try various combinations later but don't want to jump to conclusions since the Elekit is still breaking in, and all the new Mogami interconnects will require some burn-in time as well.

So far I couldn't be happier!


----------



## dawktah2

I think Western Electric beginning to make new 300B again will change the landscape.


----------



## Effusion

Congrats on the build @ProfessorC1983!

Yeah, while everyone will be different, I noticed my unit opening up and the bass getting better after about 30 hours or so.  I also eventually went with the silver/gold caps and have really enjoyed them since; many others here have also enjoyed the upgrade.  While I haven't tried the Gold Lion signal tubes, there should still be many old production out there at decent prices, however this will vary and higher-end 12au7s will tend to give better sound.  There are also options to run different options using some of the tweaks @Dimu has done.  Yeah, the hard part is the power tubes, especially since many have dried up in recent years.  The days of $50 GE 6L6GCs was really nice though!  Best advice for finding cheaper options is to use eBay, go for auctions, and just keep trying to get a good price.  Also helps to have a way to test them once they arrive, if just to make sure they are not really low on life if the seller was selling them as NOS or lightly used.  Also best to try to go with sellers that sell a lot of tubes and have pretty good reviews; tubes can get damaged during shipping and nothing is worse than a seller that won't accept them back if so.

One suggestion on power tubes are the 807s with adapters.  They are probably the only ones that are still decent in price, with a ton available.  However, in my experience, they can differ quite a bit in quality, with some sounding much better than others.  I never really cared a ton for the very common RCAs, but have had good luck at times with others.  However, inconsistencies do exist even within brands it seems, such as some Westinghouse's sounding really good, while others not so (different production years and internal materials/designs).  I also like my SED Winged C EL34's, really nice soundstage/air if I remember correctly and sweet in certain areas, but also a bit lean at times compared to some, but not as lean as some others, just about in-between many.  Unfortunately the EL34s have really gone up too, they where high in price 4 or 5 years ago as well, so Mullard and the such can be pricey, depending on their own factors, as well as harder to find.  While I primarily run my unit in Triode mode with headphones, in my experience UL mode can work a bit better with most speakers and gives more speed/impact to the drivers, as well as more wattage.  Also, I definitely prefer the EL34s in UL mode, compared to Triode with headphones, really allows them to open up and shine.  Other power tubes I feel sound better in Triode or Pentode in general and with headphones.  I haven't been able to spend much time with the unit hooked to speakers though, so my experiences there are a bit limited.

HD650s are a great choice with the 8200, I run a modded pair with mine and have always really enjoyed the result.  Honestly, due to the tweak-ability of the amp, I think the 8200 could potentially be a really good match with most headphones.  Folks here have run everything from low ohm IEMs to high ohm over the ear open backs with good results.  I've even had the pleasure of hearing the 8200 drive the Focal Utopias better than a $6,000 mega amp with thousands of dollars of tubes in it, using a specific tube combination in the 8200, and the owner of both also agreed (he was actually the first one to try and was floored at the time).  So, in my experience, synergy is very possible in many situations with this amp.

Can't really help on the Saga, but I did know of a passive pre that had a remote control that the manufacturer insisted imparts nothing onto the sound, essentially a "black" component, but this was years ago.  It was made by Fletcher Haynes Audio, https://www.facebook.com/pages/category/Electronics/FletcherHaynes-Audio-201540149902090/.  Peter is really an amazing guy, one of the last of his kind and knows a ton about tubes and tube/electrical circuits, Helen is also really great as well, very helpful and joyful... while I don't know more information about this pre-amp per se, unfortunately it also seems hard to find anything online as well, but I did see it in action in their showroom about 6 years ago, so at one time they had them.  Might be best to just contact Peter for more information, although I'll warn you that he is a very busy guy most of the year, plus it looks like his main website is no longer active, so I'm not sure the status.  The nice thing about Schiit products is that if it doesn't work out, for you and in your setup, they are generally easy to resell, so may be the best option initially.

Welcome to the club!


----------



## Effusion

Not sure why I didn't remember the switch linked below, as I actually own one, but guess I'm not sure how important the remote is for your uses and the inputs/outputs, etc.  Although my buddy is currently using mine to switch between recording devices, plus between headphones and speakers, when I did use it, prior to my Elekit, to switch between vinyl and pc it worked really great.  No real degrade in sq from what I remember, so might work as another option, just would have to press in the buttons instead of using a remote and no volume control, but it is passive, no power needed.  Plus it's cheap!

https://www.parts-express.com/parts...ite-video-selector-switch-5-in-2-out--180-938


----------



## Lasollor

I'd used a Saga to tame the gain on my TU-8200 for about a year, but sold it recently because I got a passive transformer to do the job.
I did find that with some tracks it reduced the clarity a little bit. Even after upgrading various parts of the amp, I couldn't hear it with the HD650 but noticed it sometimes with the HD800. For some reason active mode had a little hum with every tube I tried, so the above comments are about the passive mode which was completely silent. I think the functions of the Saga outweighs its effect on clarity if you need them. Just for comparison, replacing the stock volume pot on the TU-8200 had bigger effect on the clarity.


----------



## ProfessorC1983

Thanks @Lasollor -- I played with the Saga most of yesterday and unfortunately I get a pretty bad hum, regardless of whether it's in passive or active mode, and it even persists without any tube installed. It's pretty much unlistenable with headphones. Of course, if I attach the source directly to the Elekit, everything is perfect and the background is as black as I've ever heard regardless of volume level. I've reached out to Schiit for suggestions but I think I'll just return it and try another option. 

And thanks @Effusion for the suggestions! I have a very similar manual RCA switchbox right now, works great except for the lack of volume control and my girlfriend nagging me every time she has to get up from the couch to switch the input back from phono to TV.  I've been leaning toward building a semi-DIY solution based around the Joshua Tree Attenuator from Twisted Pair Audio - http://www.twistedpearaudio.com/control/jt.aspx - which uses only relays and Vishay Dale resistors in the signal path. Shouldn't be too hard to control it from an Arduino with IR receiver, and rig up a similar Omron G6K relay solution for the input switching as well. I'll let you guys know how it goes!


----------



## Effusion

Very cool, yeah I considered building one myself prior to owning the 8200 as well, different more simple design, but the price was just too good on that parts-express model at the time, plus I didn't need the volume control/remote.  Now I just use the 2nd input on the 8200 for my phono preamp, so no need anymore, but a remote would be nice.  Lasollor is right about the stock volume pot, which will actually probably be my next upgrade on the 8200, maybe sooner rather than later.  That's too bad about the Saga, wonder if something internally is screwed up with that one.  Could always try to contact Peter from Fletcher Haynes Audio, but I'm not sure if he is still active with the line, etc.  In the end, sometimes best to go with a solution that works best for all your needs, such as DIY options, etc. that you referenced.  Sounds really cool!

Yeah, let us all know how it goes and what questions you may have regarding the 8200 in the meantime!


----------



## sunneebear (Jan 6, 2019)

I was also interested in passive preamps.  After some research I settled between the twistedpear or Nelson Pass' B1 buffer.  I went with the B1.  I bought the kit with the relays but never used it because I came across a Adcom SLC-505 Straight Line Controller for $70 on Craigslist.  It was perfect.  A passive preamp and a bunch of inputs.  I have been using the Adcom since.  My brother is using the B1 and loves it.


----------



## sunneebear

My TU-8200 drives my main speakers (Jamo C 607) so yes I do use all the inputs on the Adcom.


----------



## Dimu (Jan 6, 2019)

TU-8500 is purpose-built as a preamp for TU-8200 and is a cute little project once TU-8200 assembly is finished. And it has good phono stage too. It adds a second pot, so you can control volume very precisely. And if you load it up it boosts 2nd harmonic and changes the sounds in a good way. But if you just want to attenuate signal all you have to do is plug in a couple of RCA attenuators- that has to be the simplest solution.

here is an example:

https://www.amazon.com/Harrison-Labs-Line-Level-Attenuator/dp/B0006N41B0


----------



## sunneebear

Dimu said:


> TU-8500 is purpose-built as a preamp for TU-8200 and is a cute little project once TU-8200 assembly is finished. And it has good phono stage too. It adds a second pot, so you can control volume very precisely. And if you load it up it boosts 2nd harmonic and changes the sounds in a good way. But if you just want to attenuate signal all you have to do is plug in a couple of RCA attenuators- that has to be the simplest solution.
> 
> here is an example:
> 
> https://www.amazon.com/Harrison-Labs-Line-Level-Attenuator/dp/B0006N41B0



Sadly the TU-8500 only has four inputs.  If you only need four, most relay type selectors start at four and are very cheap.  Kits came be had for $20.

Those RCA line level attenuators affect the sound.  In the 90's I tri-amped my speakers.  I used different amps to suite the characteristics of the tweeter, midrange and woofers.  Trying to match the levels for the amps, I tried those RCA attenuators.  Each brand had it's own sound.  When you have a few to AB you can tell right away that they affect the sound.


----------



## sennsay (Jan 10, 2019)

ProfessorC1983 said:


> Hi everyone... wanted to say hello, since I bought myself a TU-8200DX from Victor as a Christmas present to myself. Had a lot of fun soldering it together and now I'm waiting for it to fully burn-in. I only have about 15 hours on it, so from everything I've read I know it will only get better from here! Thanks to everyone who has participated in this thread over the years. Reading it was a delight and there's such a wealth of information here about how to customize this amazing product.
> 
> Victor talked me into the Mundorf Supreme Silver Gold caps and the Genelex Gold Lion ECC82 tubes, along with the Amtrans resistor upgrades. As for power tubes, it's really a shame the NOS market has dried up... I'm so jealous of you guys that got GE 6L6GC's for $50 a pair back in 2015! Right now they're going for $180/pair on eBay, but I figure I should bite the bullet and pick up a set since they'll soon be gone forever. I want to try the SED Winged C EL34's as well since those will also disappear. I figure I'll have years to enjoy the new-stock tubes which will hopefully get better with time.
> 
> ...


So glad you're happy with the new Elekit amp! Interesting you have the Mogami interconnects, these are something I have been meaning to buy or make myself, as I have made Mogami cables for almost all of my headphones, including two sets for my revered Sennheiser HD540 Reference (second release of the first 600 ohm model, ie; without the headband ridge). I bought these headphones from new 30 years ago now and they are still my goto cans for disappearing right into the music, the pleather pads and Mogami cable transforming them while maintaining the superbly organic musical traits that so effortlessly pour from them.
 I have just built my Elekit TU 8500 preamp 5 days ago, waiting and saving for some 18 months until I could do this. I bought up the Amtrans resistor kit, Mundorf Evo's and upgrade op-amps beforehand. After building kit gear for decades, I can easily state that this has been the finest kit to build of them all! I even went all the way and carefully filed down the joining links that hold all the boards together as they come in the fresh kit. I made a small booboo by only ordering two of the Mundorf caps, not four, but fortunately I have a stock of really nice 0.47uF polypropylene 650V caps on hand so I put them into the phono coupling section and the Mundorfs into the line stage. A also have a small stock of the fabulous and very rare now Black Gate 0.1uF NP caps and used two of them in the phono stage instead of the stock versions. I find that once these Black Gate caps run in .. and it takes a while! ... the transparency is fantastic, I've used them in several of my amps and as bypass caps for power supplies.
 Initially I used the stock tubes, in this case the preamp came with Chinese Shuguang 12AU7s and I have to admit I was rather amazed that they sounded pretty good! Lots of tuneful fun, a touch of extra tube warmth maybe, but still clear and very rhythmic, something that is the first thing I pick up on ... no rhythmic integrity, out they go! Bass was full yet did not slug timing, so I kept them in for the first 8-10 hours or so, thoroughly enjoying myself, my body instantly responding to the rhythms, no harshness or edge with AAC/Mp3 tracks from iTunes, just great fun as I sat and jived around. A really good start.
 Next day, I popped in my well used Psvane 12AU7-T's that came from my previous TRI KT88SE integrated amplifier. Blimey! These things really are still excellent tubes, taut timing, very transparent, extended and neutral in balance. I could swear I heard things in very well played tunes that I've simply never heard before, not so much overall, just little details here and there. The kit used is as in my Sig below, QP1R as a source via optical cable into the Schiit Modi Multibit DAC, Slinkylinks pure silver ICs into the preamp and the White Zombie LaCacanya ICs into a highly modded Silicon Chip headphone amp and HD540 Ref1s.
 The preamp is so utterly silent it's not surprising I could hear tiny details at the back of the soundstage suspended in their own space, very wide stereo stage and rather fine depth. The HD 540s excel (as I have them) at creating a virtual 3D space where the headphones themselves and the bones of my skull vanish and the depth perception from this system from a live concert, as in Bowie's Ziggy Stardust and the Spiders From Mars soundtrack is quite astonishing. Bowie's voice is punchy, full of natural character and yet never harsh or edgy, quite something! Bass is fast and taut, kick drum well separated behind Bowie, percussion well out to the left and almost behind my left ear, Mick Ronson's guitar soaring with fantastic creativity, especially on The Width Of A Circle and Cracked Actor.
 Even the phono stage is silent and I have to use full volume to hear even the slightest of noise, at normal listening levels and even beyond, it's effectively noiseless. Speaking of which, I really like this phono stage! Full of life, very tuneful and great imaging ... and the preamp is far from fully run in yet.
 Next, is to save up for the TU 8200. I will keep in touch with this thread to keep tube options alive and open.
PS: the pics actually show a set of Mullard ECC88s that I mistakenly thought were 12AT7s, oops!  No wonder they GLOWED brightly  Amazingly, they sounded rather good, if a bit warm and slightly soft in the top end. The Psvane 12AU7s are brilliant here.


----------



## sennsay

portlandpsu said:


> Just finished before new year


Ah, I see there are more better quality parts I can add to my TU 8500 yet  I was going to go with Nichicon FG caps in my power supply too, but thought I would just try stock for now ..... other than Mundorf Evos in the line stage, Amtran resistor kit, upgrade op-amps in the phono stage. Interesting what you've done there. SQ?


----------



## jerick70

I wanted to share my TU-8200DX build here on the thread.  I finished it last week and have been burning it in.  I switched out the stock tubes with New Production Tung-sol 6550s and NOS ribbed plate 12AU7 Mullards.  I have to say this is a gem of an amp.  The transparency in this config is fabulous. I'm running the Modwright LS100 as my preamp with Zu Audio Omen IIs for speakers and various headphones. iBasso SR-1s are my go to headphones....


----------



## jerick70

One question about the TU-8200... Can I use 12AT7s in place of 12AU7s?  I read about someone using these as an upgrade and was curious if this is possible.


----------



## ProfessorC1983

I ended up going with the Zu Omen MkII's as well -- so far they're an amazing pairing with this amp! Really floored by how much oomph they can put out with just 4W of triode power, and the forward sound signature balances well with the tube warmth from the amp. 

I also talked myself into a pair of NOS GE 6L6GC's while they're still available... huge improvement over the stock tubes! I already have the itch to roll more (thinking I may try the Winged-C EL34's next) but I need to get my preamp situation figured out first. Still thinking a DIY solution is best for my needs since I can't afford something like the ModWright.

On that note I had a couple of questions for anyone on the board who's still paying attention:

1) I'm trying to find the input impedance spec for the Elekit. The volume control I plan to use in my DIY preamp (Joshua Tree attenuator) has a fixed low output impedance of 750R... wondering if that is suitable to drive the Elekit passively or if I would need to add an active tube buffer stage in between?

2) Once I get the attenuator preamp working my plan is to remove the volume pot from the Elekit completely since I won't need it. Has anyone done this before? I assume it would just be a matter of desoldering it and adding either fixed resistors or wire jumpers across the 2 signal paths, but are there any gotchas I should look out for?


----------



## znev777

Just got one of these used, sounds great! I thought my HD6XX sounded like crap, I was pretty settled on selling them once I got my next pair of headphones. This amp opens them up very well, and now they actually have nice bass! Sound stage is also better, they aren't in my ears quite as much. And I've noticed they are also less fatiguing, maybe due to the tubes? Can't wait until I get my zmf oris, they should sound incredible on this the power thirsty planars that they are. Still using my jds element for it's dac, so I'll have to look into a nice dac as well I suppose...

What kind of tubes are a general upgrade over the electro-harmonix russian 6L6EH and the 12AU7 "China"? I like their general sound, but if I could get an appreciable upgrade for all 4 tubes for around ~$200 that would be pretty neat! I do believe this is not the DX version of the amp, so I may be a little more limited in selection. I'll have to pour over all these pages, I'm sure the answer is in there somewhere

Tubes are pretty dang beautiful, I especially like the hints of blue!


----------



## dawktah2

I'm a newbie but have Sophia EL34, NOS RCA 12AU7


----------



## znev777

I'm gonna have to make a list, so many tubes! Research is fun though, I'm going to have to do a lot of digging to try to avoid spending all my money on tubes


----------



## jerick70 (Mar 2, 2019)

znev777 said:


> I'm gonna have to make a list, so many tubes! Research is fun though, I'm going to have to do a lot of digging to try to avoid spending all my money on tubes


So far my favorite tube pairing is Tung-sol 6550s and Tungsram 6085s.  I've had my TU-8200 for about a month so I have a long way to go roling tubes though.


----------



## ProfessorC1983

znev777 said:


> I'm gonna have to make a list, so many tubes! Research is fun though, I'm going to have to do a lot of digging to try to avoid spending all my money on tubes



Unfortunately I find more research only leads me to spend more money on tubes. 

I'm still loving my NOS GE 6L6GC power tubes and have started rolling in Winged-C EL34's for variety. I want to try KT88's next, probably will go with the new Gold Lion's since there are so few affordable NOS options.

Currently looking into rolling the preamp tubes. My Gold Lion ECC82's sound good (and much better than the no-name "China's") but I want to see what I can get from NOS. It seems like clear-top RCA's and vintage Mullard's get a lot of love, but I'd be interested in hearing from others who have compared these and other NOS options! (I'm not yet quite up to the task of modding the amp to take more exotic driver tubes, but perhaps someday...)


----------



## znev777

Oof, I really should just get a decent pair of signal tubes for now, one of these chinese stock ones is hissing very slightly. I switched them, and the other side hisses so it must be them! A good number of posts have recommended the NOS RCA 12AU7, a little bit less than $30 for their higher rated ones. I just spent $360 for the amp, and another $550 for some new headphones so I really need to abstain for now.... this amp really brought out the 6XX, I can't imagine what some zmf ori's are going to sound like... I'm expecting some gnarly sub-bass for sure!


----------



## znev777

One of the stock tubes was a little hissy so I've been trying a few 12au7's, just some cheapies

First was a pair of RFT Germany 12AU7's, they sucked pretty bad, just muddled and boring. Sent them back, they were a clear downgrade from stock imo, they weren't expensive or anything but I expected more. 

Just got some Clear Top RCA 12AU7A today off of eBay, so good so far. They are nicely detailed and tight, but somewhat bright. Keepers for sure and cheap to boot, but I might still look a little for something meatier that won't fatigue me as fast as these do. 

The stock power tubes are good for now, power tubes seem to be pricier anyways and I need to cool the spending for a little bit before I try anything else


----------



## sennsay

znev777 said:


> One of the stock tubes was a little hissy so I've been trying a few 12au7's, just some cheapies
> 
> First was a pair of RFT Germany 12AU7's, they sucked pretty bad, just muddled and boring. Sent them back, they were a clear downgrade from stock imo, they weren't expensive or anything but I expected more.
> 
> ...


Hi there, I am using a matched pair of Psvane 12AU7-T's in my Elekit TU 8500 preamp, they are simply stunning! Utterly clean and neutral from top to bottom, with superb soundstage focus and vocal alacrity. They have no extra Mullard and stock Chinese 12AU7 warmth (although in saying that, the stock valves are an awful lot of fun to listen with, I had a ball while the preamp started it's run in process!), yet are musically dynamic and alive and extremely communicative. I won't be changing them out any time soon! I used to use these Psvane 12AU7-T's in my TRI TRV-88SE integrated amp and I'm very glad I kept them (the Psvane KT88-T's as well!)
I think and feel that the 12AU7-T's are quite the bargain, performing way better than some other expensive NOS valves I've heard. 
 While I know that the RCA Cleartops are also recommended for the TU 8500, I wouldn't want anything brighter to upset the superb balance I have now. That phono stage is a cracker, too! I have Mundorf cap upgrades, Amtrans resistor kit and the upgrade op-amps in my preamp. 
 Maybe you might like the Psvane 12AU7-T's too.


----------



## znev777

I'll get 35$ of store credit from the pair of tubes I'm returning so I'll probably get some nos tungsrams next, they are right on the money at $35. The store doesn't have psvane tubes unfortunately, but if the tungsrams don't work out they seem to be a good option. 

I've certainly heard good things about psvane, they seem to better than most of the new tubes coming from china and russia for sure. Most new tubes these days are just mediocre tubes with older reputable names slapped on, without bringing the same quality.


----------



## sennsay

znev777 said:


> I'll get 35$ of store credit from the pair of tubes I'm returning so I'll probably get some nos tungsrams next, they are right on the money at $35. The store doesn't have psvane tubes unfortunately, but if the tungsrams don't work out they seem to be a good option.
> 
> I've certainly heard good things about psvane, they seem to better than most of the new tubes coming from china and russia for sure. Most new tubes these days are just mediocre tubes with older reputable names slapped on, without bringing the same quality.


I've had nothing but great quality of build and sound from the Psvane tubes. I bought them from Grant Fidelity and had excellent service every time. The KT88-T's I am keeping for my next project, likely an Elekit tube amp. The Elekit TU 8500 is the finest quality kit I've come across in 45 years! Even with the instructions in Japanese


----------



## Varail

What is the right switch for ? The input selector one ?
Tx


----------



## znev777

Varail said:


> What is the right switch for ? The input selector one ?
> Tx


Yup, input selector


----------



## Varail (Mar 17, 2019)

znev777 said:


> Yup, input selector



Yes..what does it do ??

Whats the diff between up position and down ?


----------



## znev777

Varail said:


> Yes..what does it do ??
> 
> Whats the diff between up position and down ?


It switches between the two sets of red/white rca ports in the back. So if you had like a computer and a record player you could plug them both in and use that switch to switch which one the amp uses as a source.


----------



## Varail

Got it
Good to compare DACs
Thank you


----------



## znev777 (Apr 11, 2019)

Got some genelex gold lion kt66's and some tungsram hungary 12au7s, and they sounded pretty dang good, I thought I was finally done with tubes for a while... at least until one of the tungsrams started crackling and making loud POP noises, it's definitely a dud. Great, more waiting... nos tubes are such a pain in the ass, should have just gotten some psvane 12au7's....


----------



## sennsay

znev777 said:


> Got some genelex gold lion kt66's and some tungsram hungary 12au7s, and they sounded pretty dang good, I thought I was finally done with tubes for a while... at least until one of the tungsrams started crackling and making loud POP noises, it's definitely a dud and I'm surprised it got past testing. I've been ordering through Viva Tubes and I think they are a dud too, still haven't gotten the refund from my last pair of 12au7's that sounded like crap and now they send me an obviously troubled tube. Great, more waiting... nos tubes are such a pain in the ass, should have just gotten some psvane 12au7's....


I'd agree with you, the Psvane 12AU7-Ts in my TU8500 preamp are knockout and astonishingly transparent from top to bottom. I was listening to that preamp nearly all day yesterday while working on rebuilding a Marantz Model 1030, the preamp was running through a just finished Luxman SQ507X amplifier that has been completely re-capped and I was running in the refurbished power amp modules (new driver transistors too), running into a pair of old Pioneer CS-100 speakers, it all sounded amazingly alive and transparent and full of rhythmic fun. 
Although I have a couple of other tubes to use in the TU 8500, I doubt very much I could improve upon the sonic balance of the Psvanes' virtual 'no-tubes in the way' of the music. 
 I have much more saving to come yet before I can get myself and TU 8200 or similar.


----------



## vkung (Apr 5, 2019)

Revised TU-8200R will be displayed  in AXPONA 2019
The revised TU-8200 will set another new standard for low cost SET AMP.
Please stay tuned .. Another wonderful design from Mr Fujita (Master of Tube Amp in Japan)

Stereophile Review - TU-8600
https://www.stereophile.com/content/gramophone-dreams-27-elekit-tu-8600r-amplifier-kit


----------



## jerick70

vkung said:


> Revised TU-8200R will be displayed  in AXPONA 2019
> The revised TU-8200 will set another new standard for low cost SET AMP.
> Please stay tuned .. Another wonderful design from Mr Fujita (Master of Tube Amp in Japan)
> 
> ...


I should have waited.  I just purchased a TU-8200DX kit a few months ago.  

Do you know if the current TU-8200 will be upgradeable to the TU-8200R?


----------



## vkung

The revised TU-8200 is a big improvement from the OLD version. The detail will be available next week.


----------



## znev777

Faith in nos tubes restored, the tungsrams are pretty legit. Good all around and not painful like the clear tops. I think I'm done rolling for a while thankfully, might even cop a few more pairs in the future!


----------



## vkung (Apr 26, 2019)

This is the New TU-8200R. PCB-Unit 2.
Better protection circuit to prevent malfunction when Tube Rolling 
Lundhal option is possible in the near future


----------



## vkung

UNIT 1


----------



## Dimu

Thanks Victor! Layout looks familiar


----------



## vkung

They are different. There is no opt in main pcb


----------



## ProfessorC1983

Thanks Victor! What upgrades are available to TU-8200DX owners who want to get close to the 8200R level of performance? Is the Alps R27 pot the biggest change in terms of sound quality?


----------



## vkung

There is an upgrade kit to replace Unit 1 and 2. (the power transformer and OPT are the same for both versions)
The ALPS R27 is an option.  For sure the R27 is better than the stock volume pot.
Also I am working with Lundahl to design an opt for TU-8200 .
The upgrade kit is affordable for everyone.


----------



## sennsay (Apr 28, 2019)

vkung said:


> There is an upgrade kit to replace Unit 1 and 2. (the power transformer and OPT are the same for both versions)
> The ALPS R27 is an option.  For sure the R27 is better than the stock volume pot.
> Also I am working with Lundahl to design an opt for TU-8200 .
> The upgrade kit is affordable for everyone.


Hello, Victor, might there also be any upgrades for my TU8500 preamp? Say, an Alps volume pot, for instance? I pre-bought both the Amtrans resistor kit, upgrade op-amps for the phono stage and Mundorf Evo caps for the phono coupling stage before buying the kit, so that I had everything there - unfortunately at the time not realising I also needed two quality caps for the line stage, so I used the Mundorfs in the line stage and two other very nice polypropylene caps for the phono coupling. Replacing the stock 12AU7s with two top level Psvane 12AU7-Ts have transformed the preamp from an already wonderful preamp into an even greater level of neutral transparency that I've not heard from anything even remotely approaching the price of the TU8500 with it's upgrades. Absolutely brilliant piece of kit and I'm looking forward to the TU8200R in the near future.


----------



## vkung

TU-8500 does not have enough space for bigger volume pot..


----------



## Dimu

My TU-8500 has TDK pot which is better than ALPS. It was not as simple to install it as in TU-8200.


----------



## sennsay

vkung said:


> TU-8500 does not have enough space for bigger volume pot..


That's ok, the results are still fantastic!


----------



## sennsay

Dimu said:


> My TU-8500 has TDK pot which is better than ALPS. It was not as simple to install it as in TU-8200.


Righto, thank you, Is it a size issue with the TDK pot? The stock one is quite compact. Was it a big job, or just required a bit of care? 
I'm not in a rush, if I find something that does fits in there, I may give it a go.


----------



## znev777

Anyone have any experience with this amp and lcd2c's? My ori's don't seem to have any problems with it, no humming or anything (unless I turn them up stupid high, but the music masks it anyways), and they are both planars so they should be fine right?


----------



## vkung (Jul 1, 2019)

Lundhal LL2777 for TU-8200 or TU-8200R
Mr Lundhal has just sent this prototype opt to Mt Fujita for his final approval.


----------



## vkung




----------



## vkung (Jul 9, 2019)




----------



## jerick70

vkung said:


>


Are the upgrade boards and components available for the TU-8200DX now?  When will Lundhal transform upgrade be available?


----------



## znev777

I think I've settled on genalex gold lion Kt66's and rca clear top 12au7's in pentode mode. I like the dynamism! I thought the clear tops were a little bright for me, but better source material seems to alleviate that issue. It all makes for a clean, detailed, and punchy combination.


----------



## UntilThen

jerick70 said:


> Are the upgrade boards and components available for the TU-8200DX now?  When will Lundhal transform upgrade be available?



Can we have an answer to this question please?


----------



## vkung

UntilThen said:


> Can we have an answer to this question please?


ELEKIT will not offer upgrade PCB for TU-8200DX. The Lundhal is next spring. We are working on TU-8800


----------



## UntilThen

vkung said:


> ELEKIT will not offer upgrade PCB for TU-8200DX. The Lundhal is next spring. We are working on TU-8800



Thanks for the reply. I've just found the link from the preview of TU-8800. https://www.diyaudio.com/forums/elekit/342879-elekit-tu-8800-set-amp.html

It looks very interesting. It's using 7581 tubes. I suppose one could also swapped in KT88, 6L6? Yes I answered my own question. There's a switch of low, mid and high to handle various type of tubes. 

In particular, I'm interested in using Telefunken EL12 spez using an adapter. There's a forum member here @Dimu  who had used EL12 spez in his TU-8200 and like it very much. I have like 4 pairs of NOS Telefunken EL12 spez.


----------



## sunneebear

I just got my hands on a pair of Tekton Designs The Perfect SET 15.  Very good synergy with this amp.  A big speaker designed for flea amps.  Dial at 7:30-8:00 it is very loud.
.


----------



## vkung

After 3 years modification , here is the Lundahl LL2777B for TIU-8200.


----------



## vkung




----------



## eyeiaye

Hello All, I have read 40 or so pages on this forum.... such amazing knowledge here.
I have one question though... is there a recommended upgrade list anybody can provide for a first build? Perhaps some parts from mouser?

I plan on ordering and building over the holiday, but want to do it right on the first build. Perhaps a list of swapping this-for-that? Only on the most important bang for the buck components?

I do not know much about electrical engineering but have soldered a number of kits for synths. Looking forward to this project and your suggestions. I am looking for a "clean" sound.

Thanks in advance.


----------



## vkung

as long ss you follow the manual. it should be good.
i do not recommend to change the major components except the coupling caps, tube set  and OPT


----------



## eyeiaye

vkung said:


> as long ss you follow the manual. it should be good.
> i do not recommend to change the major components except the coupling caps, tube set  and OPT


Thanks so much, do you have a mouser BOM for the coupling caps, and OPT


----------



## eyeiaye

Also any other suggestions and parts


----------



## eyeiaye

Also, do you think this would pair well with the XLS Encore Speakers?
https://www.gr-research.com/store/p52/X-LS_Encore_Kit.html


----------



## vkung (Dec 15, 2020)

Do not know your speaker?
TU-8200 can drive ProAc 2.5..  It depends on  how loud you want to listen. 
For upgrade parts you can email  me


----------



## eyeiaye

vkung said:


> Do not know your speaker?
> TU-8200 can drive ProAc 2.5..  It depends on  how loud you want to listen.
> For upgrade parts you can email  me


Thanks so much! PM sent!!!


----------



## Effusion

Wow Victor, those  Lundahls look just amazing!  I'm sure they sound amazing too!

Are they available now?  The fit and finish on them looks perfect, 3 years waiting seems to be well worth it in the end!


----------



## vkung

yes.. it is pretty good


----------



## smgeiger

I bought and built my TU-8200 a couple of years ago and I loved it. I bought it from tubedepot.com. Work keeps me away a lot so it doesnʻt have a lot of hours. In the early days I did some power tube rolling but ended up settling on the original 6L6EHʻs that came with it. I had it playing yesterday and it sounded great. I played it again today and I started hearing distortion. It was from the right channel. Then the right channel went silent and the led changed to orange. I shut it down. I switched out power tubes but no help. The filaments glow. So Iʻm guessing itʻs a MOSFET and searched for replacements. Mouser no longer stocks them and it seems no one does anymore. Does anyone have a source? Thank you and Happy New Year!


----------



## vkung

Hi 
Happy New year
I have the FET in sock
You need replace the pair 6L6Gc

It is $1 each the shippping via Canada Post  no checking is $8.50
Thanks
vicor


----------



## smgeiger

Thank you vicor! Iʻll take four. How do I pay you?


----------



## vkung

If your LED turned RED.. It means too much current in your amp
You need to replace the tube set
I recommend to order  two extra two glass diodes.. 
send repayment to vkmusic.@me.com
please make sure to pick US$ otherwise PayPal will convert to C$ at the lowest exchange rate
if you have zelle you can send the $6 (4 FET 2 Diodes)+ $8.50 shipping to  vkung821@gmail.com
i will ship on monday


----------



## vkung

I refund to you
when you pay via paypal
please use vkmusic@me.com

I need you address 
and phone number

Thanks
Victor


----------



## vkung

I need to know your name
I have address..


----------



## smgeiger

Stephen Geiger


----------



## vkung

ok


----------



## smgeiger

The Q4 FET fixed it. Thank you for your help Victor!


----------



## vkung

That is good


----------



## smgeiger

I spoke too soon, I already lost the right channel again with red led. Voltage not passing through Q4. This was with a new set of 6L6 output tubes. So, today I replaced Q4 again along with Q6. I also replaced D4, ZD2, ZD4, Q2, PC2, C3, C4, C5 & C6. I installed a new set of input and output tubes and hooked to a different set of speakers. I powered up the amp and the led was blue again. I played it for about 15 minutes and checked the output tubes temperature with a laser thermometer. The left channel was around 330 degrees Fahrenheit and the right channel was about 450 degrees Fahrenheit. I turned it off. Obviously the right channel is drawing too much current. After a cooling period I powered on the amp again and red led again and dead right channel. I guessing there is issue with the auto bias circuit. Could it be the op amp? Any help resolving this would be greatly appreciated.


----------



## vkung

What is your phone number?


----------



## vkung

we can whatsapp's


----------



## eyeiaye

Hey all, wondering if there any any tubes that would be preferable for the DIY speaker build --- the XLS-ENCORE? 

Any experience or ideas?


----------



## eyeiaye

Here is a bit more detail on the speakers. 
https://www.gr-research.com/store/p52/X-LS_Encore_Kit.html


----------



## eyeiaye

eyeiaye said:


> Here is a bit more detail on the speakers.
> https://www.gr-research.com/store/p52/X-LS_Encore_Kit.html


The speakers have 8 ohm load and has 87db sensitivity. So I am wondering what mode and tubes would be best?


----------



## UntilThen

vkung said:


> we can whatsapp's



I've not seen such a helpful amp representative. Thanks Victor. You're a gem to this community.

This is my first post here because today I brought home a Elekit 8200, bought a mint condition unit from the local classified. Seller was ultra friendly and helpful in explaining to me the functions of the amp. I got it home and started listening with my favourite headphones, He1000se and LCD-3f. 

It is an amazing tone with Psvane 12au7 and Genalex Gold Lion KT88. Side by side with WA22. The latter is warmer and smoother while the 8200 is brighter with those tubes but at no time did I feel it is glaring or sibilant. In fact it is a great tone with LCD-3f. I love it and dare say even at this early stage, more than the Wa22.

Will try it out with my speakers later but for now will roll in the Electro-harmonix 6L6GC and Sylvania 12au7 for a change.


----------



## UntilThen

Stock tubes of EH 6L6GC and Psvane 12au7. Sound is now warmer and very nice. KT88 is more forceful and a more aggressive tone. I'm using Bifrost 2 as dac.

There's a bit of throbbing from the right driver, it's audible but when I place my finger on the metal plate in front of it, it disappears. Beautiful tone !!! I have been through a lot of tube amps but this is a bargain and might be the best sound I have heard so far.

Previous and current tube amps:- Feliks Elise, Euforia, La Figaro 339i, Glenn OTL amp, ALO Studio Six, Ultrasonic Studio Oblivion, Schiit Mjolnir 2, Woo Audio Wa22.

Staggering value this Elekit 8200 and I've just started listening to it. Having gone through so many tube amps, I can pick out which sound good, well to my ears. That's the disclaimer.

6L6GC is on socket saver and that raise the height. I can see the days ahead will be very engrossed with tube rolling.


----------



## UntilThen

If headphones wow me with the Elekit 8200, speakers even more. I'm using Axis LS88 floor standers rated at 150w RMS and 4 ohms 92db sensitivities. Usually I use my Sansui au alpha 907mr at 160w to drive these speakers or my Redgum Rgi120enr black series that can output 265w into 4ohms. Now I'm using Elekit 8200 in triode mode 4w, set to 4 ohms and it's driving the Axis LS88 to astounding levels - loud. Bass is really good.

With the Boston Acoustics VR-2, it's a no brainer for 8200 to drive it. BA is 8 ohms 93 dB. Drive it to it's peak. Bass is thumping and clarity and details abound.

Some pictures and my puppy is enjoying it.


----------



## UntilThen

UntilThen said:


> There's a bit of throbbing from the right driver, it's audible but when I place my finger on the metal plate in front of it, it disappears.



I've now move the amp further away from the dac and the noise disappeared. Happiness.  I can't believe how good this amp sound with either KT88 or 6L6GC with Psvane or Genalex Gold Lion 12AU7.

I'm making plans to get GEC KT66, Mullard EL34 xf2 next.


----------



## UntilThen

vkung said:


> I recommend you to replace the driver tube to Psavne Mark II 12Au7 or *Brima 12AU7*/ECC82. I like  EH6L6GC..



That's the combination I'm digging now. Psvane 12au7 with EH 6L6GC. Very good combination. Slight warm and organic. Gold Lion KT88 is more aggressive but also fun and punchy.


----------



## UntilThen

Since yesterday, I've been using He1000se with Elekit TU-8200. I've not heard this headphone sound so good. This amp is quite incredible.


----------



## Effusion

@UntilThen, congratulations!  I'm so glad you are digging the 8200 and took a chance on it!  I still use mine daily, after 7 years, and I haven't felt the need to replace it at all since!

Thank you for your impressions!  I was originally looking at the WA22 when I went with the 8200 back in 2014 and while I don't regret the decision at all, I've always wondered... if you are ever able to find the time to do an in-depth comparison, I know at least I would be very interested!

I agree, Victor is just great, so helpful/kind as well as passionate about both DIY and Elekit.  Without him I would have never have been able to audition the 8200 at RMAF and would be listening to a different, and probably sonically lesser amp, right now.

While there is a ton of really good info in this thread, it is quite extensive.  A few initial things to consider is that many here have replaced the volume pot as well as certain caps, etc. with great success.  Also, many have enjoyed running speakers in Ultra-Linear mode, so be sure to try out the different modes.  Just make sure you unplug the amp for at least 10 minutes before switching the jumpers.  Personally I prefer Triode mode with headphones, however UL mode really makes EL34s come to life!  Considering the little experience I have with speakers and the 8200, on several occasions UL mode seemed to improve speed/impact, while just slightly decreasing bloom compared to Triode; always a trade-off.  Another upgrade that looks to be promising are the new Lundahl transformers for the 8200, which I believe are available now!

The real fun of this amp is the tube-rolling, just so many possibilities!  I've found that this little amp at times can even best giants when the right pairing is found, including running Utopias noticeably better with a special combo against the very excellent Eddie Current Studio amp.

Keep letting us all know how your journey progresses and if you have any questions!


----------



## UntilThen

@Effusion good to meet you. After all you started this thread and you're still around. Elekit owes a lot to you and a lot to @vkung . There are also a lot who have contributed here and I've enjoyed reading through this thread. I'm still new to the TU-8200 - mine is the 1st version I believe. You can confirm that from the picture of the insides below.

I've a question for @Dimu but I'm afraid he has left. Or anyone who can answer this. Dimu loves using the Telefunken EL12 spez which is the predecessor tube for EL34. I always love the EL12 spez from when I was playing around with it on the Feliks Audio Elise and Euforia. It's not suited to that amp but it will play and I love the tone of all the EL11, 12 and 12 spez tubes. So much so I've bought so many NOS tubes of the EL* varieties with even the original boxes. Dimu uses the EL12 spez in the TU-8200 but I was wondering 1) what adapter did he use (if you could link me the ebay link that would be great so that I can buy the correct adapter) 2) can the EL12 spez be use with 12AU7 (because I don't know how to change the transformers to handle E80CC tubes) using the stock transformer.

Now yesterday when I pick up the amp from the seller (who happen to be a very nice and helpful person) her told me that the amp is set to triode. So all throughout yesterday when I was using it to drive my speakers and headphones, I thought I was in triode mode but this morning I open up the amp to switch it to ultra linear and to my surprise, the jumper is at ultralinear. So I was using ultrlinear all this while but I have now switch it to triode. So 2 things I observed. The amp was very powerful driving my speakers and headphones because it was in ultralinear mode and bass is very strong and nice. Today after switching over to triode mode, I find it is so much sweeter and nicer on my headphones. Haven't tried triode mode with speakers yet.

I'll be buying NOS GEC KT66 and NOS Philips Miniwatts EL34 xf2 double O rings later this week. It will cost me more than the amp but that's because I love NOS tubes and I will get it while they still exists. These are brand new and NOS. I have my source.  He also have the GEC KT88 but that will kill the cat with the price. There's also KT77 and KT90 and 6550. Sigh this amp is so good sounding that I'm really going down the tube rabbit hole but that's ok - I was already starting to buy those tubes with a view of having a custom amp build for it. Fate intervenes and here I have the Elekit TU-8200 that is already ready made for these purpose and also drives speakers so well.

I know about Eddie Current Studio and Aficionado but have not heard them. I had the Glenn OTL amp and ALO Audio Studio Six which uses 6V6 tubes. Those are good but this TU-8200 with KT88 and 6L6GC is much better to my ears that is for sure.  

Yesterday Steve the owner of https://tubesoundaudio.com.au spoke to me on the phone. They are from Australia selling those kits and also provide assembly service. Additionally they also sell very nice wooden enclosures for the TU-8200. It's magnetic so it will just hooked onto the chassis. Very clever and very nice looking. I'm interested in it. Furthermore he told me that there are differences between the new TU-8200R model from the TU-8200. One of which is the ability to change the impedance for headphones to low, medium or high. I think that is very useful.

So after a few months of usage I might sell off this TU-8200 cheap and get them to make me a TU-8200R with upgraded transformers (Lundahl ?  ), more beefy OPTs to handle E80CC and Tung Sol TT21 like what Dimu did.  

Elekit has fascinated me so much I might even be interested in the TU-8600 (300b) - that all depends on how I will reshuffle my gear which as you can see in my signature is cramped with amps and headphones. Those are very good amps IMO but this Elekit TU-8200 completely surprise and delight me. I am just so surprise that this thread has gone quiet but not anymore.


----------



## UntilThen

Today I set it up with my iMac. Yesterday it was hooked to my PC in my study. Beautiful tone !!! Pairs beautiful with Bifrost 2 and He1000se. Simple and very effective. One of the best sonic signature I've heard and amp is very quiet with no noise or hum from tubes. I'm very impressed. I'm using Psvane Art Series 12AU7 and Genalex Gold Lion KT88 with socket savers underneath the KT88.


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## JazzVinyl

UntilThen said:


> Today I set it up with my iMac. Yesterday it was hooked to my PC in my study. Beautiful tone !!! Pairs beautiful with Bifrost 2 and He1000se. Simple and very effective. One of the best sonic signature I've heard and amp is very quiet with no noise or hum from tubes. I'm very impressed. I'm using Psvane Art Series 12AU7 and Genalex Gold Lion KT88 with socket savers underneath the KT88.



Bought already assembled?


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## UntilThen (Jan 30, 2021)

With no NOS tubes to compare, I find the current production Gold Lion KT88 and EH 6L6GC to be very good. Do I really need to splash on NOS tubes? Oh well just one pair of GEC KT66 and one pair of Philip Miniwatts EL34 xf2. 

My supplier also have 2 x Brimar 6L6GA black glass and 2 x Brimar 6L6G black glass. Can these be use in the TU-8200? They are not the GC version.


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## UntilThen

On opening up the chassis, I find the fit and finish very good. Panels slide in and out precisely. They are very well machined. Screws goes in, in perfect alignment. This is quality kit. It might not look much on photo but in real life, the amp is very impressive. The chassis is solid and heavy enough not to move when you pull your headphones in and out. The LED light can be change from blue to green.

I was given a dac board for this TU-8200 but I'm not using it because my Yggdrasil and Bifrost 2 are much better. Much is an understatement.


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## UntilThen

Yesterday I compared the Elekit TU-8200 with La Figaro 339i, an amp I have regards very highly. I prefer the LF339i over the Wa22. However in an a/b with TU-8200 vs LF339i, I much prefer the TU-8200. I have no time now to have a detailed impressions now but will do so later.


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## JazzVinyl

Ah yes, I see you purchased already assembled.  As soon as I saw you with a kit amp...I thought NO WAY he assembled it.

And so it is  

Enjoy!


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## JazzVinyl

Have fun hyper-hyping your latest expenditure.


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## UntilThen

I'm usually on Tidal HiFi for playback but this rendition of 'I'll play the blues for you' on Youtube premium is so good with He1000se and Elekit TU-8200. Those KT88s can kick some serious bass and the guitars are extremely clear. There's no better way to enjoy the blues even though it's not my main genre.


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## Effusion

@UntilThen, very cool!  Thanks for the link to Tube Sound Audio and the info about their build service and wooden panels!  I do really like those panels and I might have to pick some up one day soon.  I did mod my case years ago, both paint as well as with custom cooling air flow 80mm holes and dust filters, so maybe if I pick up a "R" version... I also agree, the 8200 has the look and feel (plus design) that you would expect from high quality Japanese kits.

I own a Darkvoice, pre-La Figaro, 336se, so I'm pretty familiar with their amps and have always wanted to hear/try the 399.  Crazy, nice to hear it stacks up well and is even a bit better to your ears.  The one thing I've found throughout the years is that the 8200 always impresses me when compared to other, and much more expensive, amps!

Yes, from the pictures your amp looks like the original, non-R, version.  While I'm not sure how the headphone impedance switches compare to the original in terms of sound, many have run IEMs to very high ohm over the ears with great results on the original.  It should be somewhere in this thread, but the rated ohm of the original version was something like 8-1000 ohms with no switch needed.  So, I'm not sure why the switch is in the R version, but Victor would know or he could contact Mr. Fujita for more specifics; probably just more stable that way, etc.  The big reason I know of to go with the newer "R" version instead is that I believe there are better protection circuits for when tubes fail.  I have blown a FET in mine, due to a bad tube, and I know many others have as well, so having this protection can really be a time-saver!

I did hear the 8600 at RMAF a few years ago at Victor's table and it sounded very nice!  It was a bit hard to get great impressions at that time, since it was a noisy environment and I also believe the unit was so new, it wasn't fully broken in yet.  I'm more partial to the 8200 at the moment though personally, due to the small form factor and the tubes used; 300Bs are so darn expensive!  I like to roll quite a few different types of tubes, so having more options, especially in the NOS arena, is a positive.  However, I would suspect that the 8600 would run speakers very well and probably at least a bit better than the 8200.  Like everything though, it really depends on your speakers and system synergy.

I agree, @Dimu, has done some truly amazing things with the 8200, really bringing it when it comes to DIY!  I wish I could help with your questions more and yes, I haven't seen @Dimu post in quite awhile, but if you don't hear back, maybe Victor or someone who replicated his mods would know more.  Dimu did post a lot of specifics in this thread, but most of it was very advanced modifications and should only be done at your own risk.

I have a few different pairs of GEC KT66s and they are very nice smooth sounding tubes.  They don't have quite the slam/impact the KT88s do, but depending on genre of music, the KT66s can be quite amazing.  Think more smooth jazz and classical, whereas electronic/rock for KT88s.  As far as the 6L6s goes, I'm not entirely sure which can and can't be used.  I've always just used the GCs, but jeez, I tend to like a lot of Brimar tubes, so those might sound really nice.  Victor knows which tubes generally can and can't be used, so I'd check with him.  Definitely look into trying other variants and brands of the 12au7s too, they can really make a difference and fine-tune the sound signature.  Many really like the mids that EL34s give in the 8200, but I think they sound a bit dull in Triode mode and need UL mode to give them their spark.

That's funny about the output modes, and yes, I agree in regards to Triode for headphones on the 8200.  Let us know what you think about Triode mode with your speakers though too!  You may find the initial power/impact lacking, but it would depend on the speaker.


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## UntilThen

Thanks again @Effusion for replying and your contributions continue unabated. LF339i is so much better than DV336se and I had the DV336se before. Had a very nice picture of it too. Side by side with Elekit TU-8200, it was a close contest especially with RCA Red Hots 5693 and Tung Sol 5998 that I use on the LF339i but ultimately I find the Elekit TU-8200 as having much better impact and dynamics. It's a big sound with those KT88s. This reminds me of the Primaluna Dialogue Premium HP amp running 8 x KT88 that I had at one time. The arrival of my Redgum Rgi120enr black series made me sell off the Primaluna.

I just had confirmation from my favourite ebay seller that this adapter is for EL12 spez to EL34 / KT88 / 6L6GC. So I've ordered 2 and when it comes I'll try 2 x EL12 spez with 12AU7 drivers. I can't see it being terribly out of whack as the EL12 spez should have EL34 genes and being Telefunken they will have that famous Telefunken tone of clarity and details. That or I blow up my amp and get a new TU-8200R.  

https://www.ebay.com/itm/2017843167...=em&s=ci&mail=sys&appVersion=1.28.0&xt=104038


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## UntilThen

This was my Primaluna Dialogue Premium HP when I had it, running 8 x KT88. HD800 from this amp was gorgeous. Now Elekit TU-8200 brings back that memory.


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## UntilThen

@vkung  can I use these beautiful Brimars 6L6GA and 6L6G on the TU-8200 stock version?


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## UntilThen

These are the KT66s that I will buy over several months... from my same secret supplier.


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## UntilThen

And the EL34s..... I can't believe he kept it for me all this while...


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## UntilThen

He also has these GEC KT88s .... gonna make me broke lol. These are the most expensive of the lot. $2000 for the quad.


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## UntilThen

Finally these are what I have now for Telefunken EL11, EL12, EL12n , EL12 spez. @Dimu will hate me for hoarding them.


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## UntilThen (Jan 30, 2021)

Going to be a fun Sunday afternoon comparing 4 amps - Elekit TU-8200, Wa22, LF339i and Schiit Mjolnir 2. @xtiva will be helping me in a blind test lol. Schiit Bifrost 2 as dac.


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## urbanfox

Been following this thread for awhile, I'm really so close to buying this kit.


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## UntilThen

urbanfox said:


> Been following this thread for awhile, I'm really so close to buying this kit.



I can assure you it's worth the time and money because to my ears it sound so good and this is after I have live with those other amps for a while.


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## urbanfox

...and I'm even closer. I have most of the tubes already. Curious how my Beyer Dt880 600ohms would sound with it. Or will I go deeper down the rabbit hole and break the bank on a pair of ZMF's.


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## urbanfox

UntilThen said:


> Going to be a fun Sunday afternoon comparing 4 amps - Elekit TU-8200, Wa22, LF339i and Schiit Mjolnir 2. @xtiva will be helping me in a blind test lol. Schiit Bifrost 2 as dac.


Should be good, have heard good experiences with the WA-22


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## UntilThen

urbanfox said:


> Should be good, have heard good experiences with the WA-22



Not going to lie. Between LF339i, Wa22 and TU-8200, the contest is very close. As I listen on Chris Lea 'Looking for the summer' with He1000se and these 3 amps, I can't help but feel I really enjoy the He1000se with these 3 amps.


----------



## UntilThen

urbanfox said:


> ...and I'm even closer. I have most of the tubes already. Curious how my Beyer Dt880 600ohms would sound with it. Or will I go deeper down the rabbit hole and break the bank on a pair of ZMF's.



I had Beyer T1.2 and ZMF Verite Open both just sold off. They will be great with TU-8200.


----------



## urbanfox

Sounds like this amp is really not all that picky with its phones.


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## urbanfox

I also have a pair of HE-560 that I think sound great. But the He-1000's might need an audition.


----------



## UntilThen

urbanfox said:


> Sounds like this amp is really not all that picky with its phones.



I've here with me He1000se, LCD-3f, LCD-X and HD650. Unfortunately HD800 is not present. All sound great and HD650 is like a different animal.


----------



## UntilThen

urbanfox said:


> I also have a pair of HE-560 that I think sound great. But the He-1000's might need an audition.



My son has the HE-560 and Arya which he use on his Topping D90 / A90. I can tell you amplification wise, I much prefer these tube amps. And I have not even consider the very capable Violectric v280 which I have here. Have not even power on Mjolnir 2.


----------



## urbanfox

UntilThen said:


> I've here with me He1000se, LCD-3f, LCD-X and HD650. Unfortunately HD800 is not present. All sound great and HD650 is like a different animal.


Very nice stable of ponies my friend. I really should try a pair of the 650's. I know they sound good with tube amps. And I have a Schitt Jot, its supposed to be the natural companion to the amp.


----------



## urbanfox

UntilThen said:


> My son has the HE-560 and Arya which he use on his Topping D90 / A90. I can tell you amplification wise, I much prefer these tube amps. And I have not even consider the very capable Violectric v280 which I have here. Have not even power on Mjolnir 2.


I agree, tube amps have so much more to offer and the ability to change the sound with different tubes gives infinite tuning.


----------



## UntilThen

urbanfox said:


> ...and I'm even closer. I have most of the tubes already.



What tubes do you have already?


----------



## UntilThen

urbanfox said:


> And I have a Schitt Jot, its supposed to be the natural companion to the amp.



I too had Jotunheim and Ragnarok before but they have been sold. Amps come and go for me not because they are bad but I'm on a voyage of discovery.


----------



## urbanfox

UntilThen said:


> What tubes do you have already?


Oh man a lot, I have Quads of El34,KT 77, and 6ca7's. I have an old pair of GE 6l6gc's. I have a Cayin AT-50s and a Rogue Audio Spinx that I have been tube rolling for awhile. 12au7 I'm pretty well set.


----------



## urbanfox

I think I'm at the point where I'm going start sell of some of my amps to buy a a really good tube amp.


----------



## urbanfox

Looks like there are two kits, one has the upgraded Lundahl transformers. Is the Lundahls the way to go?


----------



## UntilThen

urbanfox said:


> Oh man a lot, I have Quads of El34,KT 77, and 6ca7's. I have an old pair of GE 6l6gc's. I have a Cayin AT-50s and a Rogue Audio Spinx that I have been tube rolling for awhile. 12au7 I'm pretty well set.



You do need an amp that can make use of those tubes. Lovely tubes. KT77 and GE 6L6gc are rare and very expensive now.



urbanfox said:


> I think I'm at the point where I'm going start sell of some of my amps to buy a a really good tube amp.



Yes that what's I'm thinking myself but TU-8200 will make me pause for quite a while .. while I play around with it. Who knows I may end up like @Effusion  and end up with this TU-8200  



urbanfox said:


> Looks like there are two kits, one has the upgraded Lundahl transformers. Is the Lundahls the way to go?



I had Lundahl transformer on my Glenn OTL amp. Definitely go for it if cost is not an issue.


----------



## urbanfox

UntilThen said:


> You do need an amp that can make use of those tubes. Lovely tubes. KT77 and GE 6L6gc are rare and very expensive now.
> 
> 
> 
> ...


I agree totally. I bought a bunch a tubes a while back not knowing they would be hard to get. I wanna cash in now on the TR-8200 and do so real tube rolling.


----------



## UntilThen

urbanfox said:


> I agree totally. I bought a bunch a tubes a while back not knowing they would be hard to get. I wanna cash in now on the TR-8200 and do so real tube rolling.



I think the TU-8200SX is the upgraded model. Not sure if Lundahl transformer is included in that. @vkung will know. There are many with those good tubes and they are going for a customised amp that will set them back quite a lot. Elekit is a good start and to my ears they are very good and could even be where you end without having to spend more. Just get an Elekit model with good parts. You can get the wooden enclosure to make it a even more finished look. Plus you get the bonus of an amp that can switch from triode, ultralinear to pentode modes and it can drive efficient speakers. My seller was using it to drive his B&W 805 and KEF LS50.  I just drove my Axis LS88 tower speakers with it.

Here in Australia, TubeSoundAudio has an amp camp (like a boot camp) where you go there for 2 days. They will guide you to make your own TU-8200R providing you with everything. You don't need to know anything. You sleep the night in the AirBNB in Blue Mountains and then the next day you go home with your new amp, all fully tested and working beautifully. They also sell TU-8500 the preamp and phono stage kit or TU-8600 the 300b version kit. Looks like a nice weekend there if I wanted to get a new TU-8200R.


----------



## UntilThen

My classical loving friend is here and I'm letting him hear the 3 amps by himself without any influence from me. He will let me know at the end which is number 1, 2 and 3. That's his opinion though. I will give mine separately.


----------



## UntilThen

Well here's my friend's verdict after listening to the 3 amps with He1000se. For Handel 'Water Music' his choice is 1) Wa22  2) TU8200  3) LF339i. For Korean K-Pop of which he is a fan, his choice is  1) TU8200  2) LF339i  3) Wa22


----------



## urbanfox

UntilThen said:


> I think the TU-8200SX is the upgraded model. Not sure if Lundahl transformer is included in that. @vkung will know. There are many with those good tubes and they are going for a customised amp that will set them back quite a lot. Elekit is a good start and to my ears they are very good and could even be where you end without having to spend more. Just get an Elekit model with good parts. You can get the wooden enclosure to make it a even more finished look. Plus you get the bonus of an amp that can switch from triode, ultralinear to pentode modes and it can drive efficient speakers. My seller was using it to drive his B&W 805 and KEF LS50.  I just drove my Axis LS88 tower speakers with it.
> 
> Here in Australia, TubeSoundAudio has an amp camp (like a boot camp) where you go there for 2 days. They will guide you to make your own TU-8200R providing you with everything. You don't need to know anything. You sleep the night in the AirBNB in Blue Mountains and then the next day you go home with your new amp, all fully tested and working beautifully. They also sell TU-8500 the preamp and phono stage kit or TU-8600 the 300b version kit. Looks like a nice weekend there if I wanted to get a new TU-8200R.


Man< I would love to go to Amp camp! What a cool idea.


----------



## urbanfox

UntilThen said:


> Well here's my friend's verdict after listening to the 3 amps with He1000se. For Handel 'Water Music' his choice is 1) Wa22  2) TU8200  3) LF339i. For Korean K-Pop of which he is a fan, his choice is  1) TU8200  2) LF339i  3) Wa22


Interesting but kinda makes sense, the WA-22 6sn7's will give more spatial presence for the orchestra music.


----------



## UntilThen

urbanfox said:


> Man< I would love to go to Amp camp! What a cool idea.



After Covid-19 restrictions are lifted, come to Australia, Sydney and we'll go to the Blue Mountains for the Amp camp in Winter. Will bring the whisky and beer and bbq and good food.  and we'll talk head-fi no doubt.


----------



## urbanfox

UntilThen said:


> After Covid-19 restrictions are lifted, come to Australia, Sydney and we'll go to the Blue Mountains for the Amp camp in Winter. Will bring the whisky and beer and bbq and good food.  and we'll talk head-fi no doubt.


I think I might have to do that, I've always wanted to see Australia. And Beer, Bbq and music are my favorite things!


----------



## UntilThen

urbanfox said:


> I think I might have to do that, I've always wanted to see Australia. And Beer, Bbq and music are my favorite things!



Hahaha looks like I've found a new friend.


----------



## urbanfox

UntilThen said:


> Hahaha looks like I've found a new friend.


Cheers Mate, whatcha drinking right now?


----------



## UntilThen

urbanfox said:


> Cheers Mate, whatcha drinking right now?



Water at the moment because I'm still evaluating the 3 amps with He1000se. Can't be tipsy to do that. 

Here's an interesting observation from both my friend and I. We both felt that LF339i though having a wide soundstage, the depth and height is not quite there. Compared to Wa22 and TU8200, these 2 have a more holographic 3D presentation. Another aspect that stood out for me is the LF339i is the darkest and warmest, followed by Wa22 and then TU8200. In fact after listening to the other 2, TU8200 sounded a bit bright by comparison. 

Here's my take:-
In terms of power and force, it's 1) TU8200 2) LF339i 3) Wa22.

In terms  of smoothness and relax, it's 1) Wa22 2) LF339i 3) TU8200

In terms of fast transient and energy, it's 1) TU8200 2) LF339i 3) Wa22

It's no wonder, Dimu prefers the E80CC followed by 6SN7 as drivers. That probably take the shine a bit away and turn the TU8200 into a smoother sounding amp. Guess choice of drivers and power tubes will also alter TU8200 sound. Likewise a darker sounding headphone like HD650 or Atticus or Verite Open or Close might be perfect for it. Turning to LCD-3f, I actually prefer the TU8200 over the other 2 amps. That said I really love the He1000se with TU8200 because I'm a clarity and details lover and also tight controlled bass. There's nothing loose here.

Lastly in terms of clarity / details, instruments separation and imaging, it's 1) TU8200 2) LF339i & Wa22 tie.

Lastly, lastly in terms of fun and tube variations, it's 1) TU8200 2) Wa22 3) LF339i

I have barely scratch the surface where tubes are concerned with TU8200. The best is yet to come. 

I'll just leave this video of Joe Bonamassa 'Drive' with you as I type and listen with He1000se and Elekit TU8200 using Psvane 12au7 and Electro Harmonix 6L6GC. Mid-bass and sub-bass is hitting very hard, top end clarity and details are extremely good. Midrange is forward and very engaging. There is an open soundscape around my head. Spatial cue is prevalent and it's wide and enveloping. My head is bobbing and my feet tapping. My shoulders are swerving. It's a great feeling ! Let's drive !.


----------



## urbanfox

Cool video, looks like it was filmed on Mulholland Drive. Man, sounds like you guys are really enjoying yourselves. Your description of the TU8200/HE1000 psvane and EH 6L6GC is what I'm looking for.


----------



## UntilThen

EH 6L6GC is warmer than Genalex KT88. I prefer it and so does Victor. He likes it with Psvane 12au7. There's a video here on 6L6GC vs KT88 vs EL34. Gives you an idea of each type tube tone. Comparing JJ and EH type. Both current production and should be cheap.


----------



## urbanfox

I think the 6L6 sounded best. I have so many tube combinations for this amp. One of the reasons I wanna get it. Thanks for sharing the video.


----------



## urbanfox

Another budget option might be the current Tung-Sol EL-34Gt's. Great tubes for the money. Gold Lion KT-77, SED winged, and the Tung-sols are my favorites in my Cayin.


----------



## UntilThen

urbanfox said:


> I think the 6L6 sounded best.* I have so many tube combinations for this amp*. One of the reasons I wanna get it. Thanks for sharing the video.



And you should get the Elekit TU-8200R or SX for that reason. The amp is not very hot after several hours of usage. Steve from TubeSoundAudio explains to me that the tubes are mounted on top of the chassis, so it's heat dissipates into the room while the chassis remains cool. Hence you can use the wooden enclosure without making the amp hotter. Now I put my hand on top of the chassis, it feels pretty cool to touch as long as you don't touch the tubes.  

The only thing that looks a bit tacky is the self adhesive labels. Would have been nice if words are engraved on the panels. The volume knob is smooth but feels light weight. No complains though as it function perfectly. However for the price, there's no reason to not like it as it is. Furthermore, if you do this yourself, you'll feel like you've created your own amp.  For me, I'd rather have it professionally soldered and assembled.  For someone who can do a Bottlehead Crack, this will be too easy.


----------



## UntilThen

urbanfox said:


> Another budget option might be the current Tung-Sol EL-34Gt's. Great tubes for the money. Gold Lion KT-77, SED winged, and the Tung-sols are my favorites in my Cayin.



Thanks I'll look into those. I will feel less heartache if I burn in those current production cheaper tubes than a pair of NOS GEC KT88 at AUD $1100.


----------



## urbanfox

Definitely, are tubes expensive for you down under?


----------



## UntilThen

We don't have much NOS tubes here. Most are from sellers in USA and Europe, unless we are buying China's production like Psvane, etc. Shipping from overseas is expensive and takes time. Sometimes though, we may get some local sellers with tubes that we're looking for. There is a shop that sells Genalax Gold Lion KT77 and seems there are only a few pairs left so I should get one pair  I look at GE 6L6GC and there aren't many on eBay and they are very expensive for GE tubes.


----------



## urbanfox

UntilThen said:


> We don't have much NOS tubes here. Most are from sellers in USA and Europe, unless we are buying China's production like Psvane, etc. Shipping from overseas is expensive and takes time. Sometimes though, we may get some local sellers with tubes that we're looking for. There is a shop that sells Genalax Gold Lion KT77 and seems there are only a few pairs left so I should get one pair  I look at GE 6L6GC and there aren't many on eBay and they are very expensive for GE tubes.


That's too bad, I think you will like having the GL KT-77 in your arsenal. Very good tubes. Very detailed.


----------



## UntilThen

urbanfox said:


> That's too bad, I think you will like having the GL KT-77 in your arsenal. Very good tubes. Very detailed.



Just paid for a pair.


----------



## UntilThen

This 2 links are very important and useful to new comers for tubes. @Effusion  I suggest you pin it on the 1st post so it's easy to locate.

https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12726831

https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12728793


----------



## urbanfox

UntilThen said:


> This 2 links are very important and useful to new comers for tubes. @Effusion  I suggest you pin it on the 1st post so it's easy to locate.
> 
> https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12726831
> 
> https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12728793


Thanks for the links. Let me know what you think of the GL KT77's, mine took a few weeks to break in.


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## UntilThen

I also order 2 sets of adapters. 807 to 6L6 adapter and EL12 spez to KT88 adapter.

https://www.ebay.com.au/itm/191604638854

https://www.ebay.com.au/itm/201784316782

@Effusion  did you end up using 6SN7 with adapters as preamp tubes? If you did, can you confirm whether you have to change the D7 rectifier and / or power transformer before you can do that? Also likewise for E80CC - did you use that and did you have to change the rectifier and / or OPT before you can do that. I think Dimu mention that you can use E80CC with 807 or 6L6GC with no changes to those 2 items.


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## UntilThen (Jan 31, 2021)

My source have some 807 but not Cossor brand and some E80CC but he didn't tell me which brand. He also have rare EL34 with metal base but I think that will cost a bomb.  

I like this Cossor 807 with white ceramic base from Langrex and might buy a pair.
https://www.ebay.com.au/itm/807-ATS...UBE/273779027002?_trksid=p2485497.m4902.l9144

These are the new NOS tubes I'll be buying -

GEC KT66 clear glass - not identical label but identical in size and construction so that's ok. I got it cheaper than off ebay.



Philips Miniwatt 6CA7 / EL34 double o rings.


----------



## UntilThen

Dimu said:


> Finally, I started listening in ultralinear mode and then I switched to triode mode, and I think I noticed some difference. However now I am planning to switch back to ultralinear next time I open the amp to give it more power which will reduce clipping.



Because of what Dimu said here, I might switch it back to Ultralinear mode - I remember when I was in UL mode, bass was more pronounced and I like it. Will loose the sweetness of triode mode though. I wish there was a switch on the amp to change the mode without having to modify by drilling a hole in the chassis.


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## UntilThen (Jan 31, 2021)

Dimu has a lot of advice and this is a good one.
https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12778104

Some interesting measurement test -
https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12797196

and interesting discovery - 
https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12820294


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## UntilThen (Jan 31, 2021)

Set it back to Ultralinear and with 12au7 and KT88 with He1000se, the bass is strong and lovely. The magic is back listening to blues - 'I'll play the blues for you' by Daniel Castro. Soundstage is wide, deep and high. It's enveloping and 3D. Tube tone is lovely. Great 2nd harmonic distortions so loved of tube amps here. It's forceful but not rough. The amp sound smooth and powerful if that makes sense. I don't get this kind of tone from 6as7 / 6080. This is big tube sound of KT88, EL34, 6L6GC for the price of a bar of candy and it sound sweet. The love for this amp grows each passing day. 

Candy Dulfer - Lily Was Here is playing now and the music is holographic. I am hearing instruments so clearly all spaced out left, right and centre, front and back. It's surreal. I paid $800 for this amp 2nd hand with all the tubes included and I'm getting a ear blast. Best purchase for a long time.

I'm entirely agreeable with this review about this amp. https://wallofsound.ca/audioreviews...rheadphone-amplifier-kit-review-by-tim-smith/


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## Effusion

UntilThen said:


> This 2 links are very important and useful to new comers for tubes. @Effusion  I suggest you pin it on the 1st post so it's easy to locate.
> 
> https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12726831
> 
> https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12728793



Done!  Funny, it has been so long since I first posted and even updated the 1st post, in doing so just now, it messed-up the formatting and the site could no longer find the original photos... anyway, I think it is basically back to normal now!


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## Effusion

UntilThen said:


> I also order 2 sets of adapters. 807 to 6L6 adapter and EL12 spez to KT88 adapter.
> 
> https://www.ebay.com.au/itm/191604638854
> 
> ...



Those 807 adapters look good!  I actually have 3 sets of 807 adapters and found them all useful.  Many of the European 807s have smaller top pins, so I use different sets to make sure they are snug.  The adapters that fit the US 807s are extremely loose on certain European 807s and you can't really use them safely.  One of my adapters works perfectly on these European brands, but they won't even begin to fit on the US brands.  They were not marked this way when I purchased them and unfortunately it was so many years ago, I'm not sure if I still have the links to them or even if all 3 are still available.

I have not used 6sn7s nor E80CC in the 8200 unfortunately, so I can't help there, but I have used many 12au7 brands/variants.  Amperex 7316 are very nice and part of the combo that beat out the Studio that day with the Utopias, but they are very expensive.  Other cheaper options are out there and more than enough to have lots of fun with.  A good place to start if you feel the 8200 has a bit too much sparkle up top is maybe some nice Mullard ones, of different types.  Typically they are smoother with great mids.


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## Effusion

@UntilThen, I'm so glad the mini-audition went well and you are really enjoying the sound!

The ATS-25s you linked below are the ones you want, with the round plates.  These ATS-25 round plates, paired with Amperex 7316s, were the combo that bested the Studio with the Utopias that day.

https://www.ebay.com.au/itm/807-ATS...UBE/273779027002?_trksid=p2485497.m4902.l9144

Yeah, keep playing around with the modes, I find that Triode is sweeter and UL is more powerful/impactful.  The wonderful thing about this amp is that there are so many options!  Thus, you can really dial-in the perfect sound for probably any genre and I have found that there really isn't a single "best" setup with this amp.

That being said, this amp is really for those who like to tweak, tube-roll, and change it up every so often.  I've seen so many owners in the past only use one set of tubes and never change the output modes; often these same owners end up going with something else down the road, which I find a bit sad.  The only draw-back to all these options is that you may find yourself like me, constantly changing things around for certain albums/genres, however many already do this with different pairs of headphones and I find it all to be quite fun!

This amp is a journey inside itself!


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## UntilThen

Thanks for the response and updating the links on the front page @Effusion . As you said, this amp is a journey in itself. Being new to it and what the other tubes can bring to change the sound, I'm certainly keen to explore. Similarly to change the mode from triode to UL or Pentode - the last I have not tried.

However even as I was listening to it in UL mode with Psvane Art Series 12au7 and Genalax Gold Lion KT88 with He1000se, I feel very contented. It's a superb tone and if this is the only tone I get then I am already happy. I don't think it's necessary to tube roll and change mode that much but for those with a tweak nature - go for it and use socket savers please to preserve the sockets and don't damage the screws thread when undoing the chassis. I suppose getting new screws is very easy - just make sure they are the correct size with washers. Last thing, give this amp some love with some decent power cord and RCA interconnects and a small power conditioner. Always help. Also a capable DAC and headphone. This amp deserves it.


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## Effusion

@UntilThen, you're very welcome!

Yes, there is so much fun to be had with the 8200!  I actually haven't tried the Gold Lion KT88 reissues yet, but weeks ago I decided I probably should and have a plan going forward, so soon.  While I do have a few pairs of KT88s, none are the original and very expensive/rare GECs.  I've also enjoyed NOS 6550s, especially the GE 6550a, which are different in appearance to the common Tung-sols.  Both of these have great bass and impact/slam/speed; the 6550 having a bit less, but other better areas than my KT88s; always seems to be a give and take relationship.  In my general opinion, the 807s are somewhere between the KT88s and KT66s, but not as refined as either.  While the militarized 807s are pretty good, sometimes they seem a bit stiff and sterile at times.  Of course this depends on the make/brand, with the ATS-25 variant being my favorite.  The nice thing is that 807s can be found easily and cheaply.

Those KT-66s and EL34s look really nice!  I have two pairs of clear glass and one smoke glass, all GEC.  I tend to prefer the clear glasses, as my smoke glass pair is a bit too polite/soft, however they are a bit sweeter/smoother.  Many have really enjoyed the EL34s in 8200 and I've tried a ton of them too, so let us know what you think!  The Mullards tend to be some of the best in the mid-range and lots of companies rebranded them, so if you can tell by the internal structure and codes, you can save some money.  The Telefunkens and blue-glass Teslas tend to have more sparkle in my experience, but sometimes a bit too thin in parts.  Also, definitely try some out some different 12au7 variants too!

That is the right way to approach this amp, find a sound that you are very content with and let it sit for awhile, but at the same time change it up every once and awhile, to either confirm our find out new good combos.  In the beginning I was trying so many different tubes/options that I got a bit fatigued and eventually found that just letting things sit for at least a day or two was helpful for comparison and ended up being more enjoyable.  Everything is relevant, so different settings can be better with certain headphones/genres too.  I also agree, even though the Elekit is low cost compared to many, it scales very nicely and deserves to be fed the best source you possibly can.

Sit back and enjoy the great sound, you've made a great purchase!


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## urbanfox

UntilThen said:


> My source have some 807 but not Cossor brand and some E80CC but he didn't tell me which brand. He also have rare EL34 with metal base but I think that will cost a bomb.
> 
> I like this Cossor 807 with white ceramic base from Langrex and might buy a pair.
> https://www.ebay.com.au/itm/807-ATS...UBE/273779027002?_trksid=p2485497.m4902.l9144
> ...


I've heard good things about the phillips miniwatts, should be outstanding! I keep an eye out for quads. Prices keep going up, so I might just have to bite the bullet, and go for it.


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## UntilThen

urbanfox said:


> I've heard good things about the phillips miniwatts, should be outstanding! I keep an eye out for quads. Prices keep going up, so I might just have to bite the bullet, and go for it.



I've good reasons to believe that the Philips Miniwatt (Holland) are the same as Mullard of UK. Just manufacture in different places but with the same specs. This seller is a private collector and he has the most astonishing collection s of NOS expensive tubes. He doesn't advertise but only sell to friends but keep some for himself. 

In time to come, NOS pairs of GEC KT66, GEC KT88 and Mullard El34 xf2 xf3 will be pretty priceless and command a big sum. These tubes seems to last over the years though and doesn't deteriorate over the years when kept and preserved. 

Wait till you step into 2A3, 45 and 300b tubes...  

Well at least we still have current production tubes and if NOS runs out, we still have the current production tubes to last a very long time. I really find the Genelax Gold Lion KT88 totally worth the dollar.


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## Effusion

I agree, these tubes are in short supply and prices will continue to rise.  The nice thing about the 8200 is that while you still have choices for NOS, if you are willing to pay, there are also options for new stock, which are getting better every day.

The best way to determine if an EL34 is a true Mullard, as well as additional info, is from the etched code on the tubes, usually to the side or behind the printed label on the tube.  These etchings do not usually ware-off, so even if the label is gone, you can still usually tell.

There are many resources available online about these codes, including the one below:
https://mullard.org/blogs/news/mullard-valve-etched-codes-how-to-interpret-them

Mullards will also typically have a single or double halo getter at the top and welded plates.  Below are a few pictures of both the halos as well as the codes:













Over the years I've been able to get really good prices on rebranded Mullards by knowing what to look for.  Many believe the ones made at the Blackburn factory are the best, with slight differences between XF1s, XF2s, XF3s, etc.


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## UntilThen (Jan 31, 2021)

Yes what I'm getting are the double O or halo getters and with xf2. He also have the more expensive D getter.

2nd picture in this link is the one I'm getting - you can see the double halo getters.
1st picture are the ones with D getters which is more expensive.
     Post #1,097 of 1,155


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## UntilThen

I'm still blown away by the Elekit TU-8200 driving my He1000se. There's a holographic ring to music. Will be back later with the Gold Lion KT77.


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## UntilThen

catcherfly said:


> I built the TU-8200 last week with the 6L6GC + 12AU7 tubes, upgraded resistors + capacitors.  I had the enclosure powder coated matte black. This was a first time build for me (and first single driver tube amp) and it took me the better part of a weekend. I could not be happier! Victor immediately answered a number of my questions while putting it together (all of which was very satisfying) and I absolutely love the sound! I'm currently running in Ultra Linear mode, listening through HiFi Man HE-400i and Audio Nirvana Super 8 Alnico full range drivers in custom built mini monitor cabinets. I have a Audio-GD NFB-28 Preamp/DAC/Balanced Headphone Amp but I much prefer the headphone section of the TU-8200. I look forward to trying different tubes at some point.



Wow a black version of Elekit TU-8200. It's beautiful !!! Elekit should offer a black version too.


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## UntilThen

Effusion said:


> With the help of the automatic bias adjustment feature, you can roll quite a few popular audiophile vacuum tubes in this amp, including the following:
> 
> Power Tubes:
> 6L6GC, KT88, 6550C, 6CA7, EL34, 5881, KT66, 807 (with adapter), KT77, KT99 as well as all of the usual direct equivalents of the 6L6GC. However, 6L6's and its variants are not recommended, only the GC.
> ...



Ok now I know for sure KT77 can be use as well as those tubes up there - including 5881, 6550C and KT99 ?  I think on the manual it says KT90 and not KT99. Can you confirm @Effusion  ?


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## urbanfox

Effusion said:


> I agree, these tubes are in short supply and prices will continue to rise.  The nice thing about the 8200 is that while you still have choices for NOS, if you are willing to pay, there are also options for new stock, which are getting better every day.
> 
> The best way to determine if an EL34 is a true Mullard, as well as additional info, is from the etched code on the tubes, usually to the side or behind the printed label on the tube.  These etchings do not usually ware-off, so even if the label is gone, you can still usually tell.
> 
> ...


great info. Thank you


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## UntilThen

I got it !


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## Effusion (Jan 31, 2021)

@urbanfox, you're very welcome!  The biggest deals to be had in NOS tubes are simply rebrands, so knowing what to look for is a real game changer.  Several manufacturers have little things like this on their rebrands, such as GE and their dot pattern, in addition to Mullard.

@UntilThen, as far as KT77 and KT99, those were edits I made according to a previous owner @Mr Chance and the post below:

https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-11429338

With that said, I haven't tried either the KT77 or KT99 in the 8200 myself, however I have been meaning to.  Victor or Elekit would be able to verify the KT99 for certain, but looking back to 2015 when this was added, Mr Chance was using the Gold Lion KT77s in his 8200 successfully.

I agree, I'm more of a fan of black or darker equipment, as silver/white is just too flashy for me most of the time.  I also painted my 8200 and modded it to dissipate heat years ago.  While I wasn't sure if heat was really an issue, the amp does get warm, especially with certain types of tubes and in certain spots over time.  Having the passive cooling system seems to help quite a bit and I can even feel the heat coming out of the filter on top.  Definitely not required though, but I thought back then if I'm already going to paint it, might as well do something else cool while I'm at it! 

https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12377376


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## UntilThen (Jan 31, 2021)

Quite a paint job there @Effusion  Your TU-8200 is transformed.

This shows the size of KT77 alongside KT88 both are from Genalex Gold Lion. KT77 is slim. KT88 is like a Sumo wrestler. The glass on both tubes are very strong and thick. These Russian made tubes looks to be high quality physically.

Now listening to the KT77.... it's brand new so I'll give it some time before spilling the beans. Just want to say that it's very quiet....just like the KT88 quietness. Impressed. Oh the shop owner thought I was buying it for my guitar amp because it's an electric guitar shop. I told him I had Jimi Hendrix guitar. 

Thought I will tag my friends so they know I'm rolling their tubes. @DecentLevi @OctavianH @connieflyer @leftside @whirlwind @UsoppNoKami @xtr4 @Sound Trooper @paramesh @Rossliew


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## urbanfox

Let those puppies break-in and enjoy. The Gold lion 12au7's are very good too.


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## UntilThen

urbanfox said:


> Let those puppies break-in and enjoy. The Gold lion 12au7's are very good too.



I have the Gold lion 12au7 given by the seller in original box. Looks like it's not been used at all. Gold shiny pins.  

KT77 tracking beautifully. I have no idea it is this beautiful but I'll let it burn in more.


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## jonathan c

Two questions for @UntilThen:  When listening to headphones via the TU-8200, do speakers have to be connected as well? What are the lowest and highest impedance headphones that you have successfully used with the TU-8200?


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## UntilThen

jonathan c said:


> Two questions for @UntilThen:  When listening to headphones via the TU-8200, do speakers have to be connected as well? What are the lowest and highest impedance headphones that you have successfully used with the TU-8200?



Speakers don't need to be connected. Inserting a headphone jack will override the connection to external loudspeakers.

I've so far use He1000se (35 ohms 95dB) LCD-X (20 ohms 96 dB) and LCD-3f (110 ohms). All performed superbly. Have HD650 (300 ohms) haven't tried it yet but see no reason why it wouldn't work. I'll check shortly.


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## UntilThen (Feb 1, 2021)

Plug in Sennheiser HD650 the king of veil and I could not believe my ears. It's sounding as good as my He1000se !!! Driven by TU-8200, I ask myself - what veil? This is superb clarity and details.

He1000se is right next to me so I plug it in again. It was then I realised how good the He1000se is. Soundstage is so much wider and the details swims all around your head. It's holographic and surreal. Put on HD650, still very good, unbelievably good but the He1000se is just so much better.  No if no buts. YMMV.


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## UntilThen (Feb 1, 2021)

According to the manual, TU-8200 will handle 8 to 1000 ohms for headphones 

For speakers, 2 settings via switch behind.

. 8 ohms to 16 ohms
. 4 ohms to 6.3 ohms


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## UntilThen

As much as I love the Wa22 and LF339i, I find myself using the Elekit TU-8200 almost exclusively today. The sonic signature of the amp is burning into my brain even as I let the KT77 burn in for 6 hours now. TU-8200 is the cheapest of my amps as I bought it used but the tone is just great. 

Starting to get a glimpse of the KT77 tone. In fact on first listen, it's already great. It seems to be half way between KT88 and 6L6gc tone. KT88 is bright and 6L6gc is warm and KT77 is somewhere in the middle but more towards 6L6gc end. So the bass is great but tight and the mid is lovely and organic. The highs is pretty sparkly. Physically it doesn't look too great. Kind of skinny and very slim, like a model. 

This could be my fav power tubes of the 3 but I'll let it burn in to the 100 hours mark. That will take 3 weeks.  by which time more tubes would have arrived.

A pic...


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## jonathan c

UntilThen said:


> As much as I love the Wa22 and LF339i, I find myself using the Elekit TU-8200 almost exclusively today. The sonic signature of the amp is burning into my brain even as I let the KT77 burn in for 6 hours now. TU-8200 is the cheapest of my amps as I bought it used but the tone is just great.
> 
> Starting to get a glimpse of the KT77 tone. In fact on first listen, it's already great. It seems to be half way between KT88 and 6L6gc tone. KT88 is bright and 6L6gc is warm and KT77 is somewhere in the middle but more towards 6L6gc end. So the bass is great but tight and the mid is lovely and organic. The highs is pretty sparkly. Physically it doesn't look too great. Kind of skinny and very slim, like a model.
> 
> ...


Well, you have a new amp-owner-in-law (...?). I just purchased a TU-8200R from a EE builder/seller on eBay. The 8200 has upgraded Mundorf aluminium capacitors, ALPS 27, and more 😄. I have my order in for Genalex/Gold Lion EL34s (cryogenically treated) and am stocked with Brimar 12au7s & Raytheon 7730s. Itching to run the gamut from Gjallarhorn JM to ZMF Auteur...from Focal Clear to Senn HD600.


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## UntilThen

jonathan c said:


> Well, you have a new amp-owner-in-law (...?). I just purchased a TU-8200R from a EE builder/seller on eBay. The 8200 has upgraded Mundorf aluminium capacitors, ALPS 27, and more 😄. I have my order in for Genalex/Gold Lion EL34s (cryogenically treated) and am stocked with Brimar 12au7s & Raytheon 7730s. Itching to run the gamut from Gjallarhorn JM to ZMF Auteur...from Focal Clear to Senn HD600.



Congratulations ! You won't regret it and if you do sell it later, it will go faster than you can put up your advert. But why would you sell this very quiet and not hot and lovely sounding amp?  GL EL34 is a good choice to partner those headphones for a euphonic, romantic and yet very clear and powerful tone. Later I suggest getting a pair of Gold Lion KT77. They are absolutely a delight.

Man you have no idea what you're stepping into. I'm very surprise this amp is not more widely adopted. Sounding good on headphones and speakers. It's a tough act to follow. There's no big brand marketing here.


----------



## UntilThen

jonathan c said:


> Well, you have a new amp-owner-in-law (...?). I just purchased a TU-8200R from a EE builder/seller on eBay. The 8200 has upgraded Mundorf aluminium capacitors, ALPS 27, and more 😄. I have my order in for Genalex/Gold Lion EL34s (cryogenically treated) and am stocked with Brimar 12au7s & Raytheon 7730s. Itching to run the gamut from Gjallarhorn JM to ZMF Auteur...from Focal Clear to Senn HD600.



I'm very tempted to sell off this used older version TU-8200 and get what you got - the upgraded TU-8200R because I've not been so hyped with a new amp before and it's the cheapest of all my amps as I bought it used.  

He1000se and Elekit TU-8200 is a match made in heaven with Bifrost 2. I think a Susvara will do nicely here. 8200 will swing that top HiFiMan like a doll and I've heard Susvara only 3 weeks ago with Hugo TT2 + M Scalar + Auris Nirvana at the shop for 2 solid hours in total concentration with just 3 people in the shop. That's a AUD $33,000 system. What I  have here is AUD $8000 system if bought new everything. It's comparable. I really want to hear a LCD4 from Elekit 8200 just to hear if I get the same experience as what I heard from Qutest --> Auris Nirvana ---> LCD4. Quite certain it's very close.


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## UntilThen

The beat and rhythm from Chris Lea 'Road To Hell' on He1000se and Elekit 8200 makes me want to take a day off work just to go through my classic rock catalogue on Tidal HiFi.


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## Effusion

@jonathan c, congratulations and welcome to the club!  Let us know how it goes and what questions you have along the way! 

@UntilThen, very cool about the KT77s, I'll have to pick up a pair!  From what I gather it is a substitute for the EL34, hence the long thin bottle design.  I also looked further into the KT90s/KT99s and they are both a drop-in for any KT88 or 6550.  I also found a post where Victor confirmed the KT90 could be used, so I believe it is a go and safe to use stock.

For those interested, I also updated the original post to include the KT90s as well as a short description of the new model, the TU-8200R, including a link to a YouTube channel that goes through how to assemble the R version.


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## jonathan c

Thank you, @Effusion and @UntilThen !  This is what I will be using for the power tubes:


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## UntilThen

Hi Jonathan, that GL KT77 are exactly what I'm using now. I'll have to switch back to KT88 to compare. Listen to a day of each because I don't want to be switching every hour. It seems the KT90 are rare now but someone is selling a quad EH KT90 for a good price but I'll go slow with tubes - I want to get a pair of Cossor 801 with white ceramic base next - from Langrex.


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## jonathan c

UntilThen said:


> Hi Jonathan, that GL KT77 are exactly what I'm using now. I'll have to switch back to KT88 to compare. Listen to a day of each because I don't want to be switching every hour. It seems the KT90 are rare now but someone is selling a quad EH KT90 for a good price but I'll go slow with tubes - I want to get a pair of Cossor 801 with white ceramic base next - from Langrex.


Not to digress too far from the “raison d’etre” of this thread, but recognition of and compliments to Langrex are in order. First class in my estimation!


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## UntilThen

GL Kt88 in the power seats now and GL 12au7 as drivers. Brighter than the KT77 but so much more 3D effect and voluptuous in tone. I really like the KT88 too. Here I have a share in Genalex Gold Lion - KT88, KT77, 12AU7 and Psvane 12au7. 

My question is - if reissue Gold Lion sound so good, how much better would the NOS equivalent be? NOS is five times the price.


----------



## jonathan c

UntilThen said:


> GL Kt88 in the power seats now and GL 12au7 as drivers. Brighter than the KT77 but so much more 3D effect and voluptuous in tone. I really like the KT88 too. Here I have a share in Genalex Gold Lion - KT88, KT77, 12AU7 and Psvane 12au7.
> 
> My question is - if reissue Gold Lion sound so good, how much better would the NOS equivalent be? NOS is five times the price.


That is an interesting case of diminishing marginal returns in the context of rationality. For tubists (tubbicts?, tuberos?, tuberas?), though, any improvement might be worth the pursuit - price be damned...I’ll risk my **s for that glow in the glass...


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## UntilThen

Hello guys who have experience with TU-8200 and TU8500, what benefits does adding a TU-8500 (tube phono stage and preamp) apart from 2 more input options, make?

Reason I am asking is that I can get my hands on a nearly new TU-8500 for half the price. Can't contain my happiness now. I will be able to use my Rega Rp8 with my desktop and stereo now with the Elekit stack.

Does adding the tube preamp add more of tube tone to the TU-8200 amp?


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## UntilThen

These are the pictures of my intended TU-8500


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## jonathan c

UntilThen said:


> These are the pictures of my intended TU-8500


That looks quite svelte inside & outside. Go for it! Think of the 8200 & 8500 as Gemini twins. Thinking about your earlier post, one possibility for you with GLs and the like is: NOS in the phono preamp stage (maximise signal quality upstream) with “new production” in the amplifier stage...


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## UntilThen (Feb 2, 2021)

Thank you Jonathan ! Gemini twins here I come !!! Brimar cv4003 in the preamp stage and Psvane 12au7 in the TU-8200. I'm so excited now I'm tripping. 

The TU-8500 was professionally installed by a shop. It's like new. So I got both the TU-8200 and TU-8500 like new with very low hours. The TU-8200 was built by a guy who is very good with building amplifier kits and who knows what he is doing. It hasn't skipped a bit since I got it.


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## jonathan c

UntilThen said:


> Thank you Jonathan ! Gemini twins here I come !!! Brimar cv4003 in the preamp stage and Psvane 12au7 in the TU-8200. I'm so excited now I'm tripping.
> 
> The TU-8500 was professionally installed by a shop. It's like new. So I got both the TU-8200 and TU-8500 like new with very low hours. The TU-8200 was built by a guy who is very good with building amplifier kits and who knows what he is doing. It hasn't skipped a bit since I got it.





jonathan c said:


> That looks quite svelte inside & outside. Go for it! Think of the 8200 & 8500 as Gemini twins. Thinking about your earlier post, one possibility for you with GLs and the like is: NOS in the phono preamp stage (maximise signal quality upstream) with “new production” in the amplifier stage (downstream). With the very low signal levels in the phono preamp stage, life expectancy of the NOS tube should be greater than if it were used in a higher gain application. The expenditure on a Brimar CV4003 or maybe on a Telefunken ECC83 thereby seems less onerous.


----------



## UntilThen (Feb 2, 2021)

Right now I'm just excited that I have an Elekit combo. I'll think of Brimar cv4003 later. Will use my Psvane 12au7 in the TU-8500 and Sylvania 12au7 in TU-8200. Paying for NOS KT66 and EL34 today.

Strangely my Sansui au alpha 907mr had channel imbalance yesterday and a friend came over and threw money in my hands and walk away with it. Now I have a new and wonderful gear in the Elekit instead and the Redgum Rgi120enr black series amp still. I was going to buy Schiit Freya + preamp but I won't now. Things evolved in my head-fi journey at a break neck speed. I'm sure I won't regret this.


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## urbanfox

jonathan c said:


> Well, you have a new amp-owner-in-law (...?). I just purchased a TU-8200R from a EE builder/seller on eBay. The 8200 has upgraded Mundorf aluminium capacitors, ALPS 27, and more 😄. I have my order in for Genalex/Gold Lion EL34s (cryogenically treated) and am stocked with Brimar 12au7s & Raytheon 7730s. Itching to run the gamut from Gjallarhorn JM to ZMF Auteur...from Focal Clear to Senn HD600.


Please update us on your journey, those are some really nice tubes!


----------



## UntilThen

Elekit TU-8500 incoming but I have a major distraction in the Kenwood KA 3300D monster amp that could be mine....  a splendid perfectly working unit in pristine condition. 

TU-8500 preamp into that Kenwood driving some big Tannoys  

Ok slowly... let me enjoy the Gemini twins first.


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## jonathan c

urbanfox said:


> Please update us on your journey, those are some really nice tubes!


Thank you, plus the CV4003s and RYT 7730s could be used, with adapters, in my other tube h/p amps: Liquid Platinum, Woo WA3.


----------



## jonathan c

UntilThen said:


> Elekit TU-8500 incoming but I have a major distraction in the Kenwood KA 3300D monster amp that could be mine....  a splendid perfectly working unit in pristine condition.
> 
> TU-8500 preamp into that Kenwood driving some big Tannoys
> 
> Ok slowly... let me enjoy the Gemini twins first.


Focus on TU8500->TU8200->LCD-X/LCD-3f/1000se. One key area: Quality of interconnects between 8500 & 8200 (already addressed?). Question: Are your headphone cables upgrade candidates? If all checks, let the Elekits elicit joy 🤩


----------



## urbanfox

jonathan c said:


> Focus on TU8500->TU8200->LCD-X/LCD-3f/1000se. One key area: Quality of interconnects between 8500 & 8200 (already addressed?). Question: Are your headphone cables upgrade candidates? If all checks, let the Elekits elicit joy 🤩


I myself believe that cables can have subtle affects on tone. I really like Kimber's and wire world. You guys are making me jones so Freakin bad!


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## Effusion

@UntilThen, congratulations!  While I haven't owned the TU-8500 nor I have really auditioned one before, many 8200 owners have really enjoyed it!  I believe some have even commented that they liked it more than the 8200!  All depends on where your biggest need is though...

I currently only have two sources going into my 8200, my DAC and my phono preamp, so no real need myself for the extra inputs the 8500 provides, however if you have multiple sources and even a record player, it can be very handy indeed!  Yes, they are designed to sit on-top of each other as a stack, so they look really good too!  As with most Elekit kits, you could do a lot worse, especially for the money, so I'm sure you'll enjoy it!

You might want to search in this thread and/or elsewhere, but I believe owners of both have commented before that the 8200 sounds even better out of the 8500.

Let us know what you think once it arrives!

*If anyone else is also interested in the 8500, it is an easier kit to build, so its a nice training exercise prior to building the 8200 too!


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## jonathan c

urbanfox said:


> I myself believe that cables can have subtle affects on tone. I really like Kimber's and wire world. You guys are making me jones so Freakin bad!


I have become a big fan / user of Arctic Cables, particularly the Palladium Series - to my brainear the closest to no cable. Anyway, the TU-8200R arrives chez moi tomorrow 🎶. The tube amp stable (harem?) will be transformer-coupled, OTL, and tube/SS hybrid. I will enjoy the 8200 in its own right and in comparison to its new tube brethren, pictured below. I also intend to point/counterpoint the 8200 versus my favourite SS amp - Violectric V280. So, to @Effusion, @UntilThen, @urbanfox, and other readers of this thread, thank you and remember the Shakespearean question that we have already answered: “tu-be or not tu-be”...


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## UntilThen

jonathan c said:


> Focus on TU8500->TU8200->LCD-X/LCD-3f/1000se. One key area: Quality of interconnects between 8500 & 8200 (already addressed?). Question: Are your headphone cables upgrade candidates? If all checks, let the Elekits elicit joy 🤩



Don't you worry I use bare silver wires point to point. I raided the silver mine.  I use Forza Audioworks cables terminated in xlr balance connector and a pig tail to 1/4 inch - Noir Hybrid HPC and Claire Hybrid HPC



urbanfox said:


> I myself believe that cables can have subtle affects on tone. I really like Kimber's and wire world. You guys are making me jones so Freakin bad!



I use QED Reference Audio 40 RCA interconnects. It's about $500 a pair.  



Effusion said:


> I currently only have two sources going into my 8200, my DAC and my phono preamp, so no real need myself for the extra inputs the 8500 provides, however if you have multiple sources and even a record player, it can be very handy indeed! Yes, they are designed to sit on-top of each other as a stack, so they look really good too! As with most Elekit kits, you could do a lot worse, especially for the money, so I'm sure you'll enjoy it!
> 
> You might want to search in this thread and/or elsewhere, but I believe owners of both have commented before that the 8200 sounds even better out of the 8500.



I got the preamp for 3 purposes :-  
1) for greater 2nd harmonic distortions - ie more tubes sound but in an audiophile way.  
2) as a preamp for more inputs - I have a Rega RP8 TT 
3) is there a remote for TU-8500 ? I may be asking too much here.



jonathan c said:


> I also intend to point/counterpoint the 8200 versus my favourite SS amp - Violectric V280.



I also have v280 and Schiit Mjolnir 2 beside Oblivion, Wa22 and LF339i. I know TU-8200 is damm good. At this point I am not interested in a detailed comparison because I'm enjoying listening to music with 8200 as a headphone amp and as a stereo amp. I have no time for comparisons. Sound is too good !!!

Here I have the 8200 in the bottom of the rake, in the spot vacated by the behemoth Sansui. It's driving my Axis LS88 tone speaker rate at 150w rms and 4 ohms 92 dB - to really good sound ! I can't believe Dire Straits sound so good with 8200 as amp duty. I'm so pleased. 

That's my Rega RP8 in the top shelf with Avid Pellar phono stage in the 2nd shelf with the Rega power supply for the TT. 3rd shelf is the Pioneer SACD player. 4th shelf is Elekit TU-8200 - kind of small


----------



## UntilThen

How does it look with both units in wooden enclosure of the same type of wood ?


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## urbanfox

UntilThen said:


> Don't you worry I use bare silver wires point to point. I raided the silver mine.  I use Forza Audioworks cables terminated in xlr balance connector and a pig tail to 1/4 inch - Noir Hybrid HPC and Claire Hybrid HPC
> 
> 
> 
> ...


very nice set-up what cartridge are you using? I have a pair of speaker cables I made from QED Silver Anniversary and Kimber connectors.


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## jonathan c

UntilThen said:


> Don't you worry I use bare silver wires point to point. I raided the silver mine.  I use Forza Audioworks cables terminated in xlr balance connector and a pig tail to 1/4 inch - Noir Hybrid HPC and Claire Hybrid HPC
> 
> 
> 
> ...


Would you put the TU-8500 on the shelf with the TU-8200? A shelf directly above the TU-8200?


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## jonathan c

UntilThen said:


> How does it look with both units in wooden enclosure of the same type of wood ?


I like the TU-8200 with the metal and wood. I would prefer that the TU-8500 have wood for the faceplate only...that’s me though...


----------



## UntilThen

urbanfox said:


> very nice set-up what cartridge are you using? I have a pair of speaker cables I made from QED Silver Anniversary and Kimber connectors.



I use Apheta mc cartridge which comes with Rega RP8. It's a $2000 cartridge.



jonathan c said:


> Would you put the TU-8500 on the shelf with the TU-8200? A shelf directly above the TU-8200?



I have 3 days to put it on this shelf then I journey back to my work accomodation - there I have 2 other HiFi racks ...



jonathan c said:


> I like the TU-8200 with the metal and wood. I would prefer that the TU-8500 have wood for the faceplate only...that’s me though...



Perhaps... I'll get the pack but just use the front facia lol.


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## UntilThen

That's my TT when I had it on my desk with the Glenn OTL amp.


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## UntilThen (Feb 3, 2021)

jonathan c said:


> Would you put the TU-8500 on the shelf with the TU-8200? A shelf directly above the TU-8200?



I'll stack it together. Looks good with the 8200 on top of the 8500.

Now my $1200 Avid Pellar phono stage will be redundant lol. This phono stage was used in Len Wallis showroom with an Avid turntable and B&W 802 D2 in white speakers. Best sound I've heard.


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## jonathan c

UntilThen said:


> I'll stack it together. Looks good with the 8200 on top of the 8500.
> 
> Now my $1200 Avid Pellar phono stage will be redundant lol. This phono stage was used in Len Wallis showroom with an Avid turntable and B&W 802 D2 in white speakers. Best sound I've heard.


If you place the 8200 atop the 8500 would you use additional feet beneath the 8200 to give the 8500 vents extra room?


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## UntilThen (Feb 3, 2021)

jonathan c said:


> If you place the 8200 atop the 8500 would you use additional feet beneath the 8200 to give the 8500 vents extra room?



What nice feet would you suggest? I see you have some feet under your Cavalii amp.

I change my mind about stacking. I'll place them side by side. There's space to do that.

I can't believe how good 'Brothers In Arms' by Dire Straits sounded on my LS88 driven by the 8w TU-8200 in ultralinear mode.


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## UntilThen

In addition to GEC KT66 and Philips Miniwatt 6CA7, I'll be getting Brimar 12au7 long plates and Philips Miniwatt 12au7. Should get it next Monday.

My supplier is keeping aside a pair of Radiotron 807, GEC KT77 and Tung Sol NOS 6550. Gulp the last 2 will cost a bomb. The 807 is so new including the box.


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## UntilThen

Just realise I have a pair of Sylvania 12au7. It's a much better tone than the GL and Psvane. Sounds organic without any trace of glare. These Sylvania pairs very well with the very clear KT77 and I just love the KT77. Looking forward to the slightly used GEC KT77. These are very rare now and expensive. Likewise the Tung Sol NOS 6550 (very rare) - they look like the KT88. The TS 6550 NOS is even more expensive than the NOS KT77. I think I will buy a pair of each of these NOS tubes from him. It's going to be a tidy sum but should last me a life time. 

When my seller heard that I'm using Gold Lion KT77, he laughed. Terrible isn't it? Guess he has so many NOS tubes, these reissues must sound so bad to him.

Sylvania 12au7 and GL KT77.


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## jonathan c

Here is something that I came across with respect to stacking 8500 & 8200. I hope that this helps.


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## UntilThen

Kind of busy today but I'm using my TU-8200 almost exclusively now. Only occasionally powering on LF339i. Not even touching the v280. That is saying much for the TU-8200. Will give impressions of Gold Lion KT77 tomorrow compared to EH 6L6gc and GL KT88.


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## UntilThen

All these gear will be moved to my other accomodation come Sunday but now just getting the speakers close for further trial. Obviously this is a temporary setup because that's no way to put the speakers that close together. Elekit TU-8200 drives this cheap spare pair of Boston Acoustics VR-2 very well. Recommended power is 10 - 150 watts, 8 ohms and 93 dB. So it's very efficient and the 8200 drives it so well. Can go very loud no problem. I'm bringing this spare pair of Boston along on Sunday. This might take some of my time off headphones and using speakers instead.


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## UntilThen

Completely forgot about the Denon DP300F tt that my wife gave me several years ago. It's packed in storage and now taken out in as new condition. Has built in phono or can be switch off to use a dedicated phono. This is an automatic turntable that is very convenient.  Not as good as my Rega Rp8 but still great with the TU-8200.


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## jonathan c

UntilThen said:


> All these gear will be moved to my other accomodation come Sunday but now just getting the speakers close for further trial. Obviously this is a temporary setup because that's no way to put the speakers that close together. Elekit TU-8200 drives this cheap spare pair of Boston Acoustics VR-2 very well. Recommended power is 10 - 150 watts, 8 ohms and 93 dB. So it's very efficient and the 8200 drives it so well. Can go very loud no problem. I'm bringing this spare pair of Boston along on Sunday. This might take some of my time off headphones and using speakers instead.


The TUBA (nice term, eh) pairing looks like fun. I am reminded of one (of many) epithet of Paul W Klipsch, pere du Klipschorns: “what this country needs is a good five-watt amplifier”.


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## UntilThen

I am so tempted to buy this https://www.stereo.net.au/forums/to...n-box-repost-price-reduced-37-lower-than-rrp/ but I had just paid $300 for these BA and the BA does sound very good for it's price and even higher.

TUBA in action.  thanks to Jonathan for coining the term.  Simple - just turntable input and Pink Floyd album 'The Wall' playing on the Denon. Can't wait for the TU8500 to arrived !


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## UntilThen

This makes me feel better about my Boston.


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## UntilThen

I'm suddenly swamped with Boston.   This is a great song.


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## jonathan c

I do not want to steer the discussion too far from the TU-8200 and it seems that the VRs are a good speaker match to the Elekit. Years ago, I bought a pair of VRs for my dad who enjoyed them for years - his next speaker step was to B&W Matrix 801 Series II (!).


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## UntilThen

Good now try and drive his 801 with the 8200.


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## UntilThen

I'm back on He1000se with TU-8200 after listening to Boston for a while. Man .... this combination is the killer. The headphone output of 8200 is really good tone. Still running Sylvania 12au7 and GL KT77. I'm just thinking of how much the NOS GEC KT77 slightly used will cost me - $450 Aussie dollars.


----------



## jonathan c

UntilThen said:


> I'm back on He1000se with TU-8200 after listening to Boston for a while. Man .... this combination is the killer. The headphone output of 8200 is really good tone. Still running Sylvania 12au7 and GL KT77. I'm just thinking of how much the NOS GEC KT77 slightly used will cost me - $450 Aussie dollars.


With the signal levels and the auto-biasing in the TU-8200, at least the KT77 life should be extended...


----------



## UntilThen

jonathan c said:


> With the signal levels and the auto-biasing in the TU-8200, at least the KT77 life should be extended...



Why's that? What's so special about KT77 other than it sound super amazing. Btw 88 is my number so in theory I should love KT88 but it's not getting so much love after I use KT77. 

Do you know how expensive and rare GEC KT77 is? Look at this pair on eBay.
https://www.ebay.com.au/itm/GEC-KT7...703939?hash=item217ae45083:g:VTkAAOSw9CdfkdSo

and do you know how rare and expensive Tung Sol NOS 6550 is?
https://www.ebay.com.au/itm/2-Tung-...821811?hash=item56f02014f3:g:SMcAAOSws19f2-U0


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## UntilThen

There's a new TU-8800, looks similar to TU-8600 but with tubes as used in TU-8200.

Here's a glowing comments on using Susvara with Elekit TU-8600R.
https://www.head-fi.org/threads/elekit-300b-amp-kit.869957/post-14049028


----------



## Effusion

Jeez, some of these NOS tubes are fetching crazy prices!  The 6550s have been hard to come by for awhile now and prices have always been quite high.  I have a Tung-Sol, RCA (rebranded Tung-Sol I believe), as well as GE 6550a pair.  All sound great in the 8200, with my current favorite being the GE.  They have many of the same characteristics as the KT88s and at times even better punch in my opinion.  Unfortunately I've read that the reissued 6550s don't sound like the originals at all though, however I have yet to try one.  While I don't have any NOS KT77s, others such as NOS EL34s have been really going up in price.  Even the once cheap GE 6L6GCs are going for twice what they did back in 2014... just crazy!  At least the 807s are still cheap!

Yeah, the TU-8800 is new kid on the block and initial impressions have been very positive!  Many past/current 8200 owners have already taken the plunge and the kit is regarded as being fairly easy to build and quite fun!  The one thing I really like about it is the extra ~4 watts of power you can get for speakers, which really helps compatibility and gives more headroom.  It can be purchased with the new Lundahls as well!

However, the 8800 does take 12at7s and not 12au7s, for which I don't believe you really want to deviate from.  While a 12au7 might run in the amp, it will probably not sound very good, or at least like it is supposed to.  Also, the 8800 will take a few power tube types the 8200 does not, which is cool, however it doesn't have a Pentode mode (which is not a deal breaker).  One interesting thing is many users have had issues running 807s in Triode mode on the 8800, whereas they run very nicely in the 8200 in Triode.

I was actually thinking about getting the "R" version of the 8200, in addition to my "DX" version, but I may just end up getting an 8800, running it with speakers and keeping my 8200 for headphones only, etc. as a desktop amp.  The nice thing about the non-R version of the 8200 is that I don't have to open it up to switch the headphone output mode each time I go from my higher ohm headphones to my lower, and vise-versa.  The big thing I like about the R version is the extra protection it has from bad tubes though, which I believe Victor has already stated isn't available as an upgrade to the non-R versions.  The 8800 also has internal headphone switches, but one owner has built a nifty top adapter that appears to work great, even though Elekit advises not to do so.  With all that being said, if anyone ever has the chance to compare the non-R to the R version of the 8200, I would be very interested if the headphone output is all that much different.


----------



## UntilThen

@Effusion you've covered all aspects of the TU-8800. While I'm keen on a TU-8600 with 300b tubes, I think my next upgrade will be a new TU-8800. I don't mind buying 12AT7 again for the drivers. 

Enough of wishing for upgrades for now because I've just started enjoying the TU-8200 with both headphones and speakers. Now that the TU-8500 preamp/phono is coming, I'm priming my turntable ready for it. I'll leave the Rega RP8 at home for when I come home to enjoy with my main stereo. I have just pull out the Denon DP300F which is a present from my wife 5 years ago when I started in head-fi. That and the NAD d1050 dac are the 2 presents from her but of course I went on to buy other crazy stuff.

So anyhoo the DP300F is like new still and I brought it to Sydney HiFi for a cartridge replacement. I was debating better *Audio Technica AT440MLa Cartridge, **Denon DL-103 Moving Coil Cartridge or **Ortofon 2M Blue Moving Magnet Cartridge.*

In the end I chose Ortofon 2M Blue Moving Magnet Cartridge. So it's vinyl and Tidal HiFi for my accomodation away from home.


----------



## UntilThen

New 2M Blue cartridge on my TT sounding so clear through TU-8200 and Hekse. No pops and crackers because my LP is very new. Dark side of the moon.


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## UntilThen

Just came back from the local meet where I brought my TU-8200 and everyone loves it and want to buy it from me. I tried many headphones with it. Meze Empyrean, HD800s, ZMF Verite Open, Dan Clark Ether 2, ZMF Auteur. All sounded great!


----------



## dawktah2 (Feb 6, 2021)

My chain: Synology NAS > TT2 > TU-8200


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## jonathan c

Here it is: TU-8200R + Woo-WA3...first up on deck DT880 250ohm chrome...


----------



## UntilThen

dawktah2 said:


> My chain: Synology NAS > TT2 > TU-8200



Gorgeous. What power tubes are you using? Great nice blueish glow. Well how about some impressions of that setup?



jonathan c said:


> Here it is: TU-8200R + Woo-WA3...first up on deck DT880 250ohm chrome...



Too early to comment on the TU-8200 in the chain? The first day I heard mine, I sat up but then my unit is used and have been burn in for at least 50 hours. The owner probably didn't put in more than 100 hours.


----------



## jonathan c

UntilThen said:


> Gorgeous. What power tubes are you using? Great nice blueish glow. Well how about some impressions of that setup?
> 
> 
> 
> Too early to comment on the TU-8200 in the chain? The first day I heard mine, I sat up but then my unit is used and have been burn in for at least 50 hours. The owner probably didn't put in more than 100 hours.


I will definitely update you. In the meantime, I switched the DT880s out and the Audeze LCD-X in. I will let the system run a few hours (CD repeat) then 👂👂. I especially want to see how the Elekit does with low impedance headphones - I have quite a few...


----------



## UntilThen

jonathan c said:


> I will definitely update you. In the meantime, I switched the DT880s out and the Audeze LCD-X in. I will let the system run a few hours (CD repeat) then 👂👂. I especially want to see how the Elekit does with low impedance headphones - I have quite a few...



Speaking about the LCD-X, I sold it last night at 10:30 pm when 2 friends came over deciding whether to buy the LCD-3f or the LCD-X. In the end one of them decide on the LCD-X. For me it's a tough choice. I like both but I like the He1000se the most so I was willing to let one of the Audeze go. Someday the LCD-3f will be replaced by the LCD-4.

Clearing my gear in preparation to buy a Mogwai Se. TU-8200 and TU-8500 will remain. The latter is not even here yet.


----------



## UntilThen

Jonathan, your new TU-8200 will change in tone over time... your tubes are also new and amp new. You're some burning in to do but at least you can hear for yourself how the sound evolve over a period of time. It's an exciting experience you get to sample only once. Once burn in, you can't unburn it lol.


----------



## dawktah2 (Feb 6, 2021)

UntilThen said:


> Gorgeous. What power tubes are you using? Great nice blueish glow. Well how about some impressions of that setup?



They are Sophia Electric EL34 grade A matched pair. Warm mid bass. The harmonics tubes add life to transparent sound you can get out of the TT2. Makes voices sound more real to my ears.
I also upgraded my caps to the Mundorf. I have NOS RCA 12AU7

My plan is to replace the TU-8200 in the cabinet with the Woo 3ES in the future. I don't think I'll ever sell it.


----------



## UntilThen

dawktah2 said:


> They are Sophia Electric EL34 grade A matched pair. Warm mid bass. *The harmonics tubes add life to transparent sound you can get out of the TT2.* Makes voices sound more real to my ears.
> I also upgraded my caps to the Mundorf.



The bold part reflects my thinking exactly. I heard Susvara with TT2 and M Scalar at the shop. Wasn't really impressed by transparent tone. When Auris Nirvana was added to that mix, then I start to see why Susvara is so good. 

Most people will love 2nd harmonic distortions from tubes. It adds to musical notes several layers of microscopic bubbles that enrich the texture of the soundscape with organic and analogue bloom. It's no wonder after all these years I'm still in love with tube amps.


----------



## jonathan c

UntilThen said:


> Speaking about the LCD-X, I sold it last night at 10:30 pm when 2 friends came over deciding whether to buy the LCD-3f or the LCD-X. In the end one of them decide on the LCD-X. For me it's a tough choice. I like both but I like the He1000se the most so I was willing to let one of the Audeze go. Someday the LCD-3f will be replaced by the LCD-4.
> 
> Clearing my gear in preparation to buy a Mogwai Se. TU-8200 and TU-8500 will remain. The latter is not even here yet.


Best wishes on the Mogwai! I will certainly let the Elekit run awhile - the KT77 and CV4003 tubes were cryogenically treated. The folks at Upscale Audio (Calif.) thus recommend added “break-in” time. Somewhat related to LCD-4, have you heard Rosson RAD-0? I actually preferred their sound to that of the LCD-4z (low impedance): more linear, no frequency dip in upper midrange/ lower treble...best planar bass that I have heard.


----------



## dawktah2

UntilThen said:


> The bold part reflects my thinking exactly. I heard Susvara with TT2 and M Scalar at the shop. Wasn't really impressed by transparent tone. When Auris Nirvana was added to that mix, then I start to see why Susvara is so good.
> 
> Most people will love 2nd harmonic distortions from tubes. It adds to musical notes several layers of microscopic bubbles that enrich the texture of the soundscape with organic and analogue bloom. It's no wonder after all these years I'm still in love with tube amps.



My dad had an H.H. Scott and I've been trying to simulate that sound.


----------



## UntilThen

jonathan c said:


> Best wishes on the Mogwai!



Plans for Mogwai Se is a couple of months away. In the meantime, I'm focussed on the Elekit combo of TU-8200 and TU-8500. 

TU-8500 should be with me on Monday, that's tomorrow.

KT77 and CV4003 tubes cryogenically treated from Upscale Audio (Calif.) should be good. You're set for a great listening experience. 

No I've not heard the Rosson RAD-0. Too many interesting headphones I would like to own but I have a limit of 2 nice ones now. Yesterday hearing Meze Empyrean and Dan Clark Ether 2 on AmpandSound Encore, I really love those combinations.


----------



## urbanfox

UntilThen said:


> The bold part reflects my thinking exactly. I heard Susvara with TT2 and M Scalar at the shop. Wasn't really impressed by transparent tone. When Auris Nirvana was added to that mix, then I start to see why Susvara is so good.
> 
> Most people will love 2nd harmonic distortions from tubes. It adds to musical notes several layers of microscopic bubbles that enrich the texture of the soundscape with organic and analogue bloom. It's no wonder after all these years I'm still in love with tube amps.


I had a feeling the GL KT77's would work out for you. They will only get better as time goes on. I've been sitting on the fence on this amp because I want to upgrade my DAC, and my addiction to tube hoarding keeps dipping into my budget.


----------



## dawktah2

UntilThen said:


> Plans for Mogwai Se is a couple of months away. In the meantime, I'm focussed on the Elekit combo of TU-8200 and TU-8500.
> 
> TU-8500 should be with me on Monday, that's tomorrow.
> 
> ...



I may need to do a TU-8500 build and get me a turntable to break out my stack of LP's


----------



## UntilThen

dawktah2 said:


> I may need to do a TU-8500 build and get me a turntable to break out my stack of LP's



I've got room for TU-8500 now.
https://www.head-fi.org/threads/sho...e-no-old-pictures-please.529140/post-16162225


----------



## UntilThen

Today TU-8500 preamp / phono stage arrived and I put NOS Philips Miniwatt 12au7 in it and I also received my NOS type for TU-8200 - in goes Brimar 12au7 long plates and Philips Miniwatt 6CA7 xf2.

Just one hour into listening and I am already overwhelmed. The combo sounds the killer. Haven't use the GEC KT66 NOS yet. The tone is awesome and the tubes are still brand new.


----------



## UntilThen

NOS tubes arrived today (all brand new unused) :-

GEC KT66
Philips Miniwatt 6CA7
Brimar 12au7 long plates
Philips Miniwatt 12au7


----------



## jonathan c

Coming soon (2) to a TU-8200R near me...


----------



## UntilThen

Jonathan how's your experience with the TU-8200R. Don't hear you talk much about it. That Sophia blue looks nice but you should try at least one pair of NOS Mullard EL34. I have that in there since yesterday. A brand new pair and it sounded even better than my Gold Lion KT77. Much much better. NOS is the way to go but it's hell of expensive now. Oh well I figure I only need a pair of each type and the Elekit is totally worth it, especially with the preamp now.

I did not expect the preamp to the amp to make that much difference but it did. I can't listen without the preamp to the mix now. The Gemini twins as you call it, is now in a league of it's own. Right up there with high end system I've heard.


----------



## jonathan c

UntilThen said:


> Jonathan how's your experience with the TU-8200R. Don't hear you talk much about it. That Sophia blue looks nice but you should try at least one pair of NOS Mullard EL34. I have that in there since yesterday. A brand new pair and it sounded even better than my Gold Lion KT77. Much much better. NOS is the way to go but it's hell of expensive now. Oh well I figure I only need a pair of each type and the Elekit is totally worth it, especially with the preamp now.
> 
> I did not expect the preamp to the amp to make that much difference but it did. I can't listen without the preamp to the mix now. The Gemini twins as you call it, is now in a league of it's own. Right up there with high end system I've heard.


Me: talk little, listen much, details later....😎


----------



## jonathan c

First off, TU-8200R is musical, inviting, beguiling, “liquid” across the spectrum. Bass is deep and “juicy”, not pronounced; midrange is dimensional and full-bodied (almost in a Renaissance art sense); treble is there - easy and extended. Ambience and vocals are rendered beautifully and convincingly. All the detail and soundstage precision is there but without “corona / eclipse” type of edging: very satisfying. My overall reaction from first extended rendezvous with Elekit: an amp for wise listeners - those seeking the real thing who confidently trust their ears and mind. My listening palette features jazz, R&B, blues and my TU-8200R experience has been via Audeze LCD-X: a wonderful synergy in spectrum and dynamic range. I will continue with my other low-impedance headphones since the hp load selector / jumper (on board unit #2) is set to “low”. The Focal Clear and Kennerton Gjallarhorn JM will get their turn on this setting. Upon jumper reset to “high”, the queue will consist of ZMF Auteur, Senn HD600 (mod), DT1770 Pro 250 ohm, DT880 Edition 600 ohm. [One note: none of the sonic delights could have been so rendered without the help of Morrow Audio Elite interconnects and of the Mojo Audio EVO dac (a resistor-to-resistor ladder unit).]


----------



## Effusion

@jonathan c, really great impressions, thank you for sharing them!  Let us know how it fares with your higher ohm headphones too!  I have modded HD650s as well as ZMF Auteurs, and both at 300 ohms sound absolutely sublime out of my non-R version.  At the same time my 80 ohm custom Beyers sound equally as amazing!  Those Sophia Electric KT88s look really nice too!  A buddy of mine has always had great luck with their tubes and loves the sound of them over many NOS!

Are you currently running the amp in Triode, Ultra-Linear, or Pentode mode?  I've found that these modes can vary greatly as well as make certain tube types really shine!

@UntilThen, I'm glad to hear the NOS EL34s are blowing you away!  I agree, while I haven't tried a ton of new stock tubes in my 8200, something about the NOS ones just give this amp more life.  They tend to make my few new stock tubes sound both thin and edgy at times, without the natural ease/flow and fullness that NOS seems to provide on a more consistent basis.  One great thing about the 8200 is that I've found it to be very responsive to tubes, so rolling them doesn't just give off very slight differences, but ones that can both be heard without much effort and enjoyed individually.  At the same time, in my opinion, the 8200 doesn't have an extremely tubey sound, so really the best of both worlds!  Be sure to go back to the new stock options and combine them in different ways at some point, if just to experiment/verify.  You may also find that those Brimar 12au7s are really making a big positive impact too!

I'm also glad you are digging the 8500!  The extra "buffer" stage of the 8500 with those Philips Miniwatt 12au7s probably adds some really nice tube bloom!

 to both of you!


----------



## jonathan c

Effusion said:


> @jonathan c, really great impressions, thank you for sharing them!  Let us know how it fares with your higher ohm headphones too!  I have modded HD650s as well as ZMF Auteurs, and both at 300 ohms sound absolutely sublime out of my non-R version.  At the same time my 80 ohm custom Beyers sound equally as amazing!  Those Sophia Electric KT88s look really nice too!  A buddy of mine has always had great luck with their tubes and loves the sound of them over many NOS!
> 
> Are you currently running the amp in Triode, Ultra-Linear, or Pentode mode?  I've found that these modes can vary greatly as well as make certain tube types really shine!
> 
> ...


The TU-8200R default setting for output is ultralinear. In time I will switch to pentode / triode mode to give them a go. I am pleased thus far. When I do run the Auteur, DT1770, and HD600 through the “high” impedance setting, I will certainly, for fun, compare the experience with that from the Woo WA3 OTL. Happy 👂🎶 to you.


----------



## UntilThen

Got socket savers for all tubes and running GEC KT66 for the very first time of this brand new pair. Will be back next month for impressions.


----------



## jonathan c

UntilThen said:


> Got socket savers for all tubes and running GEC KT66 for the very first time of this brand new pair. Will be back next month for impressions.


Do you think that there is enough space above the tube tops? Where does the heat go?


----------



## UntilThen

Oh lots of air circulation. Have air con and big quiet stand fan if need be. 4 hours last night and barely warm. Those glass panel are think and can take heat. Elekit doesn’t feel hot at all compared to LF339


----------



## UntilThen

There more room between tube and glass above than it looks. I can change tubes without pulling out the amp.


----------



## jonathan c

UntilThen said:


> There more room between tube and glass above than it looks. I can change tubes without pulling out the amp.


😀👍 Given their price, I would hate to see the life of those wonderful tubes shortened by operating in high ambient temperatures.


----------



## UntilThen

jonathan c said:


> 😀👍 Given their price, I would hate to see the life of those wonderful tubes shortened by operating in high ambient temperatures.



Never I know what I am doing been rolling tubes for 5 years. Sarcasm are best kept to yourself.


----------



## jonathan c

UntilThen said:


> Never I know what I am doing been rolling tubes for 5 years. Sarcasm are best kept to yourself.


I did not intend sarcasm.


----------



## jonathan c

To @Effusion and @UntilThen:  I have been extending my sessions with the TU-8200R now fitted with the Sophia Electric EL34s. I let the system run for close to five hours on CD repeat before donning the ZMF Auteur...to bathe in the most engaging, most enthralling, most involving, most realistic (in a headphone context) sound that I have encountered. All the usual audiophile parametres and sub-categories were evident but it was the gestalt that thrilled me the most. I did actually compare the “low” versus “high” impedance setting. I am keeping it at “low”:  the high-Z Auteur, DT1770, and HD600 all were more communicative to me at the “low” versus “high” impedance setting. There was more “there” there (🙄). At the low-Z end of the hp spectrum, the Audeze LCD-X were at their level best. I am waiting for a custom SE amp-termination cable for the Clear and the Gjallarhorn (same 3.5mm termination) - what I have has XLR amp-termination. I cannot wait since the Gjallarhorn is still my favourite “overall” headphone. I will post.


----------



## Effusion

Awesome!  Very cool and interesting in regards to your impressions of the headphone output settings, really good to know!  I'm also glad to hear the Sophias are working out so well!  Would you say they are way beyond the KT77s overall, just a few steps above, or on par, but just different?

For sure, let us all know how it continues to go with the Clears/Gjallarhorns as well as the tube break-in!


----------



## jonathan c

Effusion said:


> Awesome!  Very cool and interesting in regards to your impressions of the headphone output settings, really good to know!  I'm also glad to hear the Sophias are working out so well!  Would you say they are way beyond the KT77s overall, just a few steps above, or on par, but just different?
> 
> For sure, let us all know how it continues to go with the Clears/Gjallarhorns as well as the tube break-in!


I am relieved and pleased with the perceived outperformance of headphones in the “low” impedance setting. First, it is consistent with my experience with other amplifiers that have low output impedance: LP and Violectric V280. (The Woo WA3 as an OTL h/p/a is a ‘special situation’: I would use only high-Z h/p.) Second, I really did not want to have to frequently open up the amp to adjust the Z when switching h/p. Onto the Sophia EL34s:  finesse with force, panache with power...not a huge step up from the Genalex KT77...enough to give notice that the music is being faithfully served...


----------



## UntilThen

An incredible sounding pair of tubes. The EL12 spez. My favourite from the days of Elise and now too. It's playing now in an amp that can truly exploit it's full potential. Elise wasn't built to use it.


----------



## UntilThen

This is Telefunken. The black one above is Tesla. A bit different tone. Marvellous tubes though. The Telefunken sound better to me but only just.


----------



## dawktah2

jonathan c said:


> To @Effusion and @UntilThen:  I have been extending my sessions with the TU-8200R now fitted with the Sophia Electric EL34s. I let the system run for close to five hours on CD repeat before donning the ZMF Auteur...to bathe in the most engaging, most enthralling, most involving, most realistic (in a headphone context) sound that I have encountered. All the usual audiophile parametres and sub-categories were evident but it was the gestalt that thrilled me the most. I did actually compare the “low” versus “high” impedance setting. I am keeping it at “low”:  the high-Z Auteur, DT1770, and HD600 all were more communicative to me at the “low” versus “high” impedance setting. There was more “there” there (🙄). At the low-Z end of the hp spectrum, the Audeze LCD-X were at their level best. I am waiting for a custom SE amp-termination cable for the Clear and the Gjallarhorn (same 3.5mm termination) - what I have has XLR amp-termination. I cannot wait since the Gjallarhorn is still my favourite “overall” headphone. I will post.



I'm glad you enjoy these tubes. These are the ones I have. I'm not sure if you picked them up after my post.


----------



## jonathan c

It looks as though it was soon after. Wonderful to hear through...wonderful to look at...


----------



## Nikonkit

Can anyone enlighten me re using the 8200 solely as a headphone amplifier, l was told that the speakers terminals have to be attached to a pair of speakers in order not to blow the transformer


----------



## UntilThen

Nikonkit said:


> Can anyone enlighten me re using the 8200 solely as a headphone amplifier, l was told that the speakers terminals have to be attached to a pair of speakers in order not to blow the transformer


Not true. No speakers need to be attached. If you have speakers attached and you plug in your headphone jack then the speakers will be cut out.


----------



## barbz127

Hi all, new to elekit but would anyone know why they moved from external switches back to pcb jumpers with the 8200r update?

More importantly would anyone who has assembled on think there is a way to extend the headphone power selector to the back panel via dip switches or similar?

I'm considering one of these for a headphone amp and have 13ohm and 300ohm headphones but see myself only using it for one or the other if this is hidden.

Thankyou


----------



## jonathan c

barbz127 said:


> Hi all, new to elekit but would anyone know why they moved from external switches back to pcb jumpers with the 8200r update?
> 
> More importantly would anyone who has assembled on think there is a way to extend the headphone power selector to the back panel via dip switches or similar?
> 
> ...


I am with you on this one. I love the sound (re)produced by the TU-8200R, but the jumper situation is clearly inconvenient. I keep the impedance setting at “low” and use the amp for my low-Z ( < 100 ohms) hp. My high-Z hp are driven by an OTL Woo WA3. (I did not build the amp; it was built by an EE).


----------



## barbz127

Thankyou,

Did you ever run it in high/med mode and compare the 8200 to your OtL?

I'm in the market for a single tube amp to do a bit of everything.

I might hitup a local builder to see what they can to make output power selection easier.

My guess is hiding it on the pcb ensures power is cut before making a change.


----------



## UntilThen

Hi Barbz, good to see you here and good to hear you're about to get a 8200R for yourself. 

I'm not sure what mine is set to. I've not changed it since buying it over. Although I did open up the case to change from UL to triode and to UL again twice. Even this would have been nice to have an external switch. Now mine is left in UL mode.


----------



## jonathan c

barbz127 said:


> Thankyou,
> 
> Did you ever run it in high/med mode and compare the 8200 to your OtL?
> 
> ...


I did in fact compare the 8200 “high”-Z mode with the WA3 for ZMF Auteur, Beyer DT1770, Senn HD600 (Custom Cans UK mod) and felt that there was a _touch_ more “there-ness” with the WA3. Was that OTL, maybe? Was that the WE 421a with Amperex PQ 7316, maybe?


----------



## UntilThen

A friend is bringing over a Mchanson amp that can run 6L6GC, KT77, KT88, KT150, EL34 over soon for me to compare with the Elekit TU-8200. Suddenly there's a proliferation of amps that can run these tubes. Choices are always good.

It's a model similar to this
https://www.ebay.com.au/itm/1146469...y5IvRKaJCkZIw0nuhpFQrgzSUCS9axyhoCOxYQAvD_BwE


----------



## barbz127

UntilThen said:


> A friend is bringing over a Mchanson amp that can run 6L6GC, KT77, KT88, KT150, EL34 over soon for me to compare with the Elekit TU-8200. Suddenly there's a proliferation of amps that can run these tubes. Choices are always good.
> 
> It's a model similar to this
> https://www.ebay.com.au/itm/1146469...y5IvRKaJCkZIw0nuhpFQrgzSUCS9axyhoCOxYQAvD_BwE


I'm really interested to hear about this, ive been talking to your friend and Eric about these builds. Make sure they bring the 300b amp over too!


----------



## UntilThen

barbz127 said:


> I'm really interested to hear about this, ive been talking to your friend and Eric about these builds. Make sure they bring the 300b amp over too!


Oh no he does not have the 300b amp with him but I’ll get to hear it another day.

I will see what Mchanson amp Dennis has later because I will be going to his place after I have audition the KT150 at my place... to get a Mullard gz34.

It’s going to be an eventful Sunday.


----------



## Nikonkit

Thanks very much for your help, l am going to get one if that's the case


----------



## dawktah2

UntilThen said:


> Oh no he does not have the 300b amp with him but I’ll get to hear it another day.
> 
> I will see what Mchanson amp Dennis has later because I will be going to his place after I have audition the KT150 at my place... to get a Mullard gz34.
> 
> It’s going to be an eventful Sunday.


Western Electric is making 300B tubes again so it will be nice to hear a NOS vs. NEW


----------



## UntilThen

dawktah2 said:


> Western Electric is making 300B tubes again so it will be nice to hear a NOS vs. NEW


300b tubes are not in my radar now as I'm still chasing KT88, EL34 NOS. Plenty to keep my wallet occupied.


----------



## UntilThen

My dalliance with Mcchanson KT150 amp and my impression of it vs Elekit TU-8200 going from memory.

https://www.head-fi.org/threads/eric-mcchanson-headphone-amp.718350/post-16192442


----------



## barbz127

UntilThen said:


> 300b tubes are not in my radar now as I'm still chasing KT88, EL34 NOS. Plenty to keep my wallet occupied.


With the tubes you've tried in the 8200 to date do you have a favorite type (kt66/77/88/el34) ?


----------



## UntilThen

barbz127 said:


> With the tubes you've tried in the 8200 to date do you have a favorite type (kt66/77/88/el34) ?


I've a lot of favourites amongst the NOS tubes in the order of preference but they are very close, separated by a hair's breath:-

Telefunfen EL12 spez with adapter
GEC KT66
Philips Miniwatt 6CA7 tie with EFT EL34. In fact these 2 are so close to the GEC KT66 in terms of preference, I would put them all three on the same level.

Next comes the current production tubes which are very good if you didn't listen to the NOS tubes:-
Genalex Gold Lion KT77
Genalex Gold Lion KT88
Electric Harmonix 6L6GC - this is the stock power tube.

Drivers that I have in order of preference:-
Brimar 12au7 long plates - there is a difference between the long plates and just the normal Brimar 12au7 - in terms of SQ and price.
Philips Miniwatt 12au7 - nice warm tone
Sylvania 12au7
Psvane 12au7
Gold Lion 12au7

I have Amperex 12au7 and Tung Sol 1960s 12au7 coming later at $400 a pair. I was assured by my astute seller that these will clean your ears and internal organs. 

I have GEC KT77 used coming later. Also coming later is the Tung Sol 1960s 6550. Much much later will also come the money sucking GEC KT88 NOS brand new. Canadian maple leaf and Radiotron 807 have been purchased. 

For Odyssey, I have tubes set aside additionally for my. Brimar 12ax7 that I was told is older than Methuselah. Mullard 12at7 with gold pins that is rarer than the Queens's corgi. 596 rectifier that is next in line to the throne of USA.... was going to say England but these are JAN USAF so it was made for the United States Air Force. F16s use them when they were F1s. Philco 5u4g, Mullard 5u4g, 5u4g from West Germany. 

Alright I'll take a breather. It's getting tiring just by typing all these !!!


----------



## barbz127

Thankyou, 

I have half a dozen brimar 12au7 long plates so that should keep me going for a while.

Eying off a set of mullard el34's....I should probably buy the amp first


----------



## UntilThen

barbz127 said:


> Thankyou,
> 
> I have half a dozen brimar 12au7 long plates so that should keep me going for a while.
> 
> Eying off a set of mullard el34's....I should probably buy the amp first


You're already equipped then with those lovely sounding Brimars !!!

Yes definitely buy the Ferrari first before you installed a super sexy after market stereo with subwoofers in it !


----------



## barbz127

A question for those of you with both the 8500 and 8200;

Do you have better or worse control over the volume with the 8500 in the chain? I feel like this is a dumb question but figured I should ask just in case.

And how do you use it? Full volume on the 8500 and use the volume control on the amp? or the other way around?

Thankyou


----------



## UntilThen

If I may answer this. I set preamp to 2 pm and then adjust volume on amp to suit. It’s all experimental but that seems to work for me. I probably could set the preamp to full volume and thereby have less play on the amp but experiment. The ELEKIT combo performed flawlessly so far. I find no fault with it.


----------



## barbz127

Dumb question sorry, the search isnt working for me.

How important it is to have matching input/power tubes?

Some amps that I have owned havent been too picky in this regards but im unsure about the 8200.

Thankyou


----------



## UntilThen

barbz127 said:


> Dumb question sorry, the search isnt working for me.
> 
> How important it is to have matching input/power tubes?
> 
> ...


Don't think matching tubes is important but always nice to have. I buy very nice driver and power tubes. My private seller never mentioned about them being matched but they are NOS and sound lovely to me.

If possible buy a nice NOS pair. You don't need all the different type of tubes unless it's your mission to sample them all. If you just have NOS pairs of KT66 and EL34, that is more than enough. Similarly for drivers. With Brimar 12au7 long plates, you don't need more. My drivers have never been swapped out since. Those Brimars stays in the sockets.


----------



## barbz127

Thankyou - just keeping an eye out for anything special/different to grab - I found a set of GE 6L6GC's in the cupboard also so between them, the brimar long 12au7's I should be sorted.


----------



## UntilThen

Those GE 6L6GC are very good and expensive to buy now. You should just start off with those Brimars and GE. It's a very good start !


----------



## barbz127 (Feb 24, 2021)

Is it safe to run 5814wa tubes in the tu8200r (and tu8500)?

From what I can see 12AU7 draws in 150/300mA compared to the 5814A that draws in 175/350mA.

Thankyou


----------



## Johnscheley

I have a TU 8200. It was assembled by a friend.  It's my headphone amplifier.  
I suggest 3 simple upgrades that put this baby amplifier on the level of amplifiers that cost thousands of dollars.
 1) NOS valves 
2) Better coupling capacitors 
3) Lundhal output transformers

The last upgrade was impressive.  These transformers are very good. They make this amplifier more organic, natural and truly tube  sound.  Worth every dollar spent.  It is worth talking to @vkun  and promoting these improvements.


----------



## UntilThen (Feb 25, 2021)

Johnscheley said:


> I have a TU 8200. It was assembled by a friend. It's my headphone amplifier.
> I suggest 3 simple upgrades that put this baby amplifier on the level of amplifiers that cost thousands of dollars.
> 1) NOS valves
> 2) Better coupling capacitors
> ...


I've had Lundahl transformer in my Glenn OTL amp. I won't be upgrading my TU-8200 because I've a custom amp being ordered with Sowter transformers and Mundorf caps and other goodies. Elekit TU-8200R is a precursor to my new SET amp call Odyssey. I use TU-8200 to burn in my NOS tubes and of course to listen to music while waiting for Odyssey - which has similar tube compliments as Elekit TU-8200. 

I miss my TU-8200 and TU-8500 combo because I left it in my work accommodation while I'm now in Sydney. However I'll be returning to the Elekit combo this Sunday.

I did make some enquiries from https://tubesoundaudio.com.au/ about Lundahl transformer for TU-8200R and they don't seem to know about it even though they sell both kit and fully assembled TU-8200R and TU-8600R.


----------



## GDuss

Johnscheley said:


> I have a TU 8200. It was assembled by a friend.  It's my headphone amplifier.
> I suggest 3 simple upgrades that put this baby amplifier on the level of amplifiers that cost thousands of dollars.
> 1) NOS valves
> 2) Better coupling capacitors
> ...



I will be building a TU-8200R soon, with Lundahl OPT's and Mundorf capacitors.  Everything is ready to start, except the silver solder is not here yet.

Regardless of the amp and the build, working with Victor is such a pleasant experience.  My first contact with him was an email I sent on a Sunday evening.  He called my cell phone 20 minutes later to discuss my questions.  I didn't even ask him to call me and honestly thought I would get a reply in a few days, but I had barely hit send on the email and was already on the phone with him  .  And every email I have sent gets a reply within 30 min.  Outstanding service.  If you are thinking of buying an Elekit you should definitely work with Victor (assuming you are at least in the Western hemisphere).  Others in this thread have already mentioned his great service, I'm just adding to the positive feedback.

I'm sure the amp will sound great too.


----------



## UntilThen

Congrats @GDuss . I'm sure your joy with the TU-8200R will be further heightened with such customer service from Victor. He single handed make the Elekit brand better known in North America.

I've not heard my headphones with TU-8200 for a week and I'm missing it much.


----------



## GDuss

UntilThen said:


> Congrats @GDuss . I'm sure your joy with the TU-8200R will be further heightened with such customer service from Victor. He single handed make the Elekit brand better known in North America.
> 
> I've not heard my headphones with TU-8200 for a week and I'm missing it much.



Thanks UT.  Hopefully you get back to your Elekit soon, and in the meantime you are listening to some top-notch equipment!!!


----------



## UntilThen

GDuss said:


> Thanks UT.  Hopefully you get back to your Elekit soon, and in the meantime you are listening to some top-notch equipment!!!


This Sunday. I'm just commuting between Sydney and Canberra. A tale of 2 cities. Despite all the other good sounding amp, I'm still particularly fond of the Elekit combo. Each time I change the NOS power tubes, I get a different tone... different but wonderful.


----------



## Johnscheley

GDuss said:


> I will be building a TU-8200R soon, with Lundahl OPT's and Mundorf capacitors.  Everything is ready to start, except the silver solder is not here yet.
> 
> Regardless of the amp and the build, working with Victor is such a pleasant experience.  My first contact with him was an email I sent on a Sunday evening.  He called my cell phone 20 minutes later to discuss my questions.  I didn't even ask him to call me and honestly thought I would get a reply in a few days, but I had barely hit send on the email and was already on the phone with him  .  And every email I have sent gets a reply within 30 min.  Outstanding service.  If you are thinking of buying an Elekit you should definitely work with Victor (assuming you are at least in the Western hemisphere).  Others in this thread have already mentioned his great service, I'm just adding to the positive feedback.
> 
> I'm sure the amp will sound great too.


I really agree.  Victor's work is outstanding.


----------



## UntilThen

You should get a pair of Brimar 12au7 long plates. Beats the Psvane or Gold Lion 12au7 any day. They aren't too expensive ... yet. These drivers stay in my amp and has not been changed for weeks. I can get Amperex and Tung Sol 1960s 12au7 at $400 a pair but I'm in no hurry because the cheaper Brimar is very good. Remember to get the long plates. They are better than the short ones.  

https://www.ebay.com.au/itm/One-PAI...055424?hash=item2183f90380:g:Bb8AAOSwT5xZQ2b1

https://www.ebay.com.au/itm/Matched...117814?hash=item1ab499a4f6:g:sdoAAOSwPPZgM-hQ


----------



## GDuss

UntilThen said:


> This Sunday. I'm just commuting between Sydney and Canberra. A tale of 2 cities. Despite all the other good sounding amp, I'm still particularly fond of the Elekit combo. Each time I change the NOS power tubes, I get a different tone... different but wonderful.



You have some very nice tubes for the amp so I'm not surprised you miss it.

I'm excited to listen to the amp, but I'm also excited to work on the build.  When I built the Crack, it was a happy time to finally get to listen to it when it was completed, but it was also sad to be done with the construction.  So maybe I will just go slow and enjoy this one.


----------



## UntilThen

It's always fun when you build your own amp. You can say, I made it !!!  However don't go too slow because TU-8200R sounds better when completed.


----------



## GDuss

UntilThen said:


> It's always fun when you build your own amp. You can say, I made it !!!  However don't go too slow because TU-8200R sounds better when completed.



Luckily I have some other amps to keep me entertained in the meantime, but most of them I did not build.

Good idea on the Brimar tubes.  They are still affordable.


----------



## dawktah2

UntilThen said:


> It's always fun when you build your own amp. You can say, I made it !!!  However don't go too slow because TU-8200R sounds better when completed.



I wouldn't mind building it over. I was in a hurry to build mine, I missed a solder joint. After I kept hearing a crackle opened up unit and found it. Purist say resistors/ capacitors should not touch the circuit board, I'd like to place them all with a little air gap.


----------



## cddc

barbz127 said:


> Is it safe to run 5814wa tubes in the tu8200r (and tu8500)?
> 
> From what I can see 12AU7 draws in 150/300mA compared to the 5814A that draws in 175/350mA.
> 
> Thankyou



Interesting question. Have you tried your premium 6SN7 tubes on the TU-8200 amp, @UntilThen ?

If 6SN7 works, then it should be safe to run 5814 tubes.


----------



## UntilThen

cddc said:


> Interesting question. *Have you tried your premium 6SN7 tubes on the TU-8200 amp*, @UntilThen ?
> 
> If 6SN7 works, then it should be safe to run 5814 tubes.



No. I don't believe you can use 6SN7 in TU-8200 amp. Someone here change the transformer to be able to do that. I won't go to that extend.

My new SET amp Odyssey though can use 6SL7, 6SN7, 12au7, 12at7, 12ax7 as well as 2 x Telefunken EL11.


----------



## cddc

Cool, you've got some really nice 6SN7 tubes, it would be great if they work on the TU-8200 amp.


----------



## UntilThen

I sold off some of my very nice 6sn7 together with Studio Six amp. Now I have to start collecting them again.

Fortunately my new amp need only one double triode to work. Pretty much like my previous Glenn OTL and Studio Six.

Top of my list to get are ECC32, ECC33, Sylvania 6sn7w metal base, RCA 5692, Tung Sol 6sn7gt bgrp, Sylvania 6sn7gt bad boys 3 holes.


----------



## cddc

I remember you had some really nice ECC32's, kind of pity you sold them off. They are now harder to find and quite expensive to buy.


----------



## UntilThen

That's the circle of life. I thought I have given up tubes lol.


----------



## UntilThen

Came back to my TU-8200 after one week and I could not believe what I've miss. If this is the only amp I'll ever get, then I'd be totally happy.


----------



## GDuss

UntilThen said:


> Came back to my TU-8200 after one week and I could not believe what I've miss. If this is the only amp I'll ever get, then I'd be totally happy.



What is your current set of tubes in the amp?  Brimar 12AU7 and what power tubes?


----------



## UntilThen

GDuss said:


> What is your current set of tubes in the amp?  Brimar 12AU7 and what power tubes?



For drivers:-
Brimar 12au7 long plates, Philip Miniwatt 12au7, Psvane 12au7, Sylvania 12au7, Gold Lion 12au7. 

For power tubes:-
NOS - GEC KT66, Philips Miniwatt 6CA7 (EL34), RFT EL34, Telefunken EL12 spez, Tesla EL12 spez, Canadian 807, Radiotron 807.
Current production - Genalex Gold Lion KT88, KT77, Electro Harmonix 6L6GC.

Up coming purchase:-
GEC KT88, GEC KT77, Tung Sol 6550 1960s, GEC TT21, Telefunken EL156, GE 6L6GC, Philips Miniwatt 6CA7 xf2 'D' getter. 
Amperex 12au7, Tung Sol 12au7 1960s.

That's it. 
Rest of purchase are for Odyssey. Of course these can also be used in Odyssey.


----------



## barbz127

UntilThen said:


> For drivers:-
> Brimar 12au7 long plates, Philip Miniwatt 12au7, Psvane 12au7, Sylvania 12au7, Gold Lion 12au7.
> 
> For power tubes:-
> ...


Would you have any thoughts on how the psvane 12au7 differ to the brimars?


----------



## UntilThen

barbz127 said:


> Would you have any thoughts on how the psvane 12au7 differ to the brimars?


Brimar 12au7 just sounded smoother and yet very detailed. Once I switch over to the Psvane 12au7, it just feel like raw. Strangely before I had the Brimars, the Psvane sounded ok. Once you heard NOS tubes it's hard to go back to current production tubes.


----------



## GDuss

UntilThen said:


> For drivers:-
> Brimar 12au7 long plates, Philip Miniwatt 12au7, Psvane 12au7, Sylvania 12au7, Gold Lion 12au7.
> 
> For power tubes:-
> ...



That's an impressive list of tubes (current and future).  And it's great you can use them in multiple amps.  I don't have other amps that use the same power tubes, so I'm starting from scratch with this Elekit.  My plan is to try to stick to “modest” tubes, like RCA or GE 6L6GC or maybe the current production Gold Lion KT66.  But we all know how that goes.

The ZMF Pendant uses 12AU7 so at least I can share those tubes between amps. And I already have some NOS tubes from that amp (Mullard, Ken Rad, RCA, Raytheon, and soon some Mazda's; still working on the Brimar long plates).  But the 12AU7's are still in good supply and at reasonable prices for many of them.

Just need to never listen to those crazy expensive EL34's so I won’t know what they sound like.


----------



## UntilThen

So you have the AmpandSound Pendant. I was contemplating either Mogwai Se or Bigger Ben but I decided to go for a custom amp using those tubes.

You have 2 beautiful sounding amps already.

The most expensive tubes in that range are the GEC KT88.


----------



## GDuss

UntilThen said:


> So you have the AmpandSound Pendant. I was contemplating either Mogwai Se or Bigger Ben but I decided to go for a custom amp using those tubes.
> 
> You have 2 beautiful sounding amps already.
> 
> The most expensive tubes in that range are the GEC KT88.



The Pendant is a spectacular amp but my understanding is that it sounds different than the other AmpsandSound amps (I have only heard the Pendant, not their others). The Pendant sounds like a solid-state amp with a generous dose of tube magic added to it.  It is very fast with great extension on both ends and can have excellent detail with the right tubes.  I think their other amps are more classically tube-sounding according to feedback I have heard from others.   I'm very curious to hear where the TU-8200R (with the upgraded transformers and caps) falls on this scale of sound.


----------



## barbz127

Can anyone confirm what the headphone impedance selector changes on the 8200r? 

Is it just changing the output impedance of the socket or something else entirely?

Thankyou


----------



## jonathan c

barbz127 said:


> Can anyone confirm what the headphone impedance selector changes on the 8200r?
> 
> Is it just changing the output impedance of the socket or something else entirely?
> 
> Thankyou


The jumper selection is for the output impedance.


----------



## UntilThen

GDuss said:


> The Pendant is a spectacular amp but my understanding is that it sounds different than the other AmpsandSound amps (I have only heard the Pendant, not their others). The Pendant sounds like a solid-state amp with a generous dose of tube magic added to it.  It is very fast with great extension on both ends and can have excellent detail with the right tubes.  I think their other amps are more classically tube-sounding according to feedback I have heard from others.   I'm very curious to hear where the TU-8200R (with the upgraded transformers and caps) falls on this scale of sound.


Thanks for the feedback on Pendant. Haven't heard both Ampandsound amps, I won't speculate but a look at the tubes used will provide some idea. However amp implementation is more important and will determine the eventual sound. 

I look forward to your comparison of 8200r vs Pendant.


----------



## barbz127

UntilThen said:


> For drivers:-
> Brimar 12au7 long plates, Philip Miniwatt 12au7, Psvane 12au7, Sylvania 12au7, Gold Lion 12au7.
> 
> For power tubes:-
> ...


@UntilThen what power tubes do you find you're using more often out of your current selection?


----------



## UntilThen

All three - EL12 spez, KT66 and EL34.


----------



## UntilThen

I may roll in the Gold Lion KT88 and KT77 just to see how they perform now after a long absence.


----------



## barbz127

With regard to the headphone output in the 8200r; I was reading elsewhere today where the output impedance has gone from ~95 ohm with the tu8200 to ~220 ohm with the tu8200r.

Is there any way to reduce this so it's more compatible with lower impedance headphones?

Is there any downside/risk to connecting headphones to the speaker outputs to access 4/8ohm outputs?

Or am I over thinking it?

Looking to run DCA aeon closed, verite closed and maybe a empyreans should I opt to treat myself this year.

Thankyou


----------



## UntilThen

I don't know the answer to this but the place where you bought the 8200r should be able to tell you.


----------



## barbz127

UntilThen said:


> I don't know the answer to this but the place where you bought the 8200r should be able to tell you.


Thankyou - I'll reach out.

Based on your positive experiences with the HE1000SE and TU-8200; the rule of thumb where the output impedance should be lower than the headphones is null and void given the HE1000SE are 35ohm headphones.


----------



## aedaza

Hi all,
I'm considering changing the coupling caps from the Amtrans Amco caps to Mundorf evo silver gold ones. Has anyone made that change? Interested to know your findings... Sound went towards analytical/clean? Or warmer/organic?


----------



## ProfessorC1983

So I've been really enjoying my TU-8200DX for the past couple of years... mostly listen to vinyl with my Sennheiser HD650s but I also use it with a pair of Zu Omen MKII's for watching TV. My usual preferred tube pairing is NOS Brimar CV4003 and Gold Lion KT88, although I did make the rectifier upgrade to use Valvo E80CC with GE 6L6GC.

Only slight complaint is it's developed a bit of a 60hz hum which isn't too bad when sound is playing but does annoy me... anyone else have this happen? Anything obvious to check?

I'm also getting the itch for an upgrade but not sure what to focus on since this combo is so perfect... the new Lundahl transformers maybe? Or keep the Elekit as-is and get a new set of cans? Any recommendations that you are liking better than the HD650s?


----------



## Effusion

@ProfessorC1983, I've run my DX almost every day since 2014 and it hasn't developed any sort of hum, so there may be a slight issue with yours.  In my experience this is generally due to a tube(s), so maybe swapping them out and seeing if it goes away might be a good place to start.  Also, does the hum increase when you turn the pot and thus the volume up?  If not, it may be a ground hum instead.

I also have extensive experience with the HD650, stock and modded, paired with the DX, but recently I've been really enjoying my new ZMF Auteurs.  The Auteurs are very neutral and have more resolution/detail.  However, they tend to have a slightly smaller soundstage and less of an upper bass hump than the HD650s, which makes bass notes a bit more clean, but not as full.  The bass impact has improved through burn-in and pad changes though.  All in all, I've been very happy with the Auteurs when paired with the DX, so much so that I haven't really thought about my HD650s much since I got them.

In my experience, the TU-8200 pairs well with many high-end headphones, so really any that you want to try should sound great!  If it is an either/or decision, I suggest looking into a new headphone choice first, as it should give you a bigger change in flavor overall and more options.  However, the Lundahls should provide a nice sound quality upgrade with the HD650s, so really about if you think you are looking for a change in flavor vs. better quality sound as is.

Cheers to the TU-8200DX!


----------



## barbz127

8200r with mundorf oil caps and lundahl transformer has arrived.

Currently on speaker duties with some usher s520's while I paint my office where my headfi setup lives.

New production Millard el34 and tungsols 12au7's are the current tube preference but will start rolling through my collection soon enough.


----------



## UntilThen

barbz127 said:


> 8200r with mundorf oil caps and lundahl transformer has arrived.



Smart setup that will sound awesome. My TU-8200 is being restored by Jules, who knows everything. He's replacing resistors and caps and FET for me. I will also have Mundorf caps but chose not to spend on Lundahl trannies for my Elekit because I have Odyssey coming with Sowter transformers.


----------



## jerick70

barbz127 said:


> 8200r with mundorf oil caps and lundahl transformer has arrived.
> 
> Currently on speaker duties with some usher s520's while I paint my office where my headfi setup lives.
> 
> New production Millard el34 and tungsols 12au7's are the current tube preference but will start rolling through my collection soon enough.


Awesome amp.  I built the DX version and I’m really happy with it.  I may upgrade to the R version.


----------



## barbz127

UntilThen said:


> Smart setup that will sound awesome. My TU-8200 is being restored by Jules, who knows everything. He's replacing resistors and caps and FET for me. I will also have Mundorf caps but chose not to spend on Lundahl trannies for my Elekit because I have Odyssey coming with Sowter transformers.


Glad to hear you're getting it sorted although it looks like you've had plenty of fun with other amps while the 8200 has been offline.

I have a resistor box made by Lachlan/passion for sound that connects to the speaker terminals and drops the output Impedance from 230ohm down to 1ohm.

Sounds magic in testing and can't wait to get the 8200 moved back to the office for headfi duties.


----------



## UntilThen

jerick70 said:


> Awesome amp.  I built the DX version and I’m really happy with it.  I may upgrade to the R version.



Jerick !!! Have you been in hiding? Haven't seen you for ages.  

Now how about some pictures of your DX.


----------



## jerick70

UntilThen said:


> Jerick !!! Have you been in hiding? Haven't seen you for ages.
> 
> Now how about some pictures of your DX.


Hey mate how’s it going!  Yes long time no see. Nope I’ve been on the board just must have missed each other.  It’s really good to see you.

Here is my DX with the Elekit 8500 preamp


----------



## UntilThen

jerick70 said:


> Hey mate how’s it going! Yes long time no see. Nope I’ve been on the board just must have missed each other. It’s really good to see you.
> 
> Here is my DX with the Elekit 8500 preamp



That's nice ! Sadly I sold off my TU-8500 preamp. That combo takes it up to another level imho. Coincidentally I just bought a mint pair of Tung Sol 6550 1960s just like yours. Great sounding tubes. Btw 807 tubes with adapters in the TU-8200 sound great but one of the tube was the culprit that took out my Elekit.

Didn't you buy the TU-8600R too?


----------



## jerick70

UntilThen said:


> That's nice ! Sadly I sold off my TU-8500 preamp. That combo takes it up to another level imho. Coincidentally I just bought a mint pair of Tung Sol 6550 1960s just like yours. Great sounding tubes. Btw 807 tubes with adapters in the TU-8200 sound great but one of the tube was the culprit that took out my Elekit.
> 
> Didn't you buy the TU-8600R too?


Is that An odyssey?  The Tungsol 6550 is a nice tube.  

No I didn’t end up getting the 8600.  I am a huge 300b fan, but the best tubes cost as much or more than the amp.  The economies of scale just aren’t there for 300b.


----------



## UntilThen

jerick70 said:


> Is that An odyssey?  The Tungsol 6550 is a nice tube.
> 
> No I didn’t end up getting the 8600.  I am a huge 300b fan, but the best tubes cost as much or more than the amp.  The economies of scale just aren’t there for 300b.



Nope that's not Odyssey. That Greek hero will be built in my Winter of 2021 - that's next month. Will use a silver solid aluminium chassis with Sowter output tranformers, Hammond power transformer and choke, Mundorf caps and Yamamoto sockets. Will use 6SL7 / 6SN7 drivers or a pair of Telefunken EL11. Power tubes are as varied as the TU-8200.

I did get a 300b amp a month ago, build by a seasoned local amp builder who's been doing it for 40 over years. Took him just one week to complete and I call it Destiny ! It's the cause of my disrupted sleeps for a month already and doesn't look like stopping. Whether with headphones or speakers, it is just heavenly.

That's the gold Destiny on the left and the amp builder's own KT88 set amp in triode mode on the right.


----------



## sennsay

jerick70 said:


> Hey mate how’s it going!  Yes long time no see. Nope I’ve been on the board just must have missed each other.  It’s really good to see you.
> 
> Here is my DX with the Elekit 8500 preamp


I'd really like to buy one of those DX kits, it's next on the list. I really love my TU8500, I bought the resistor upgrade kit separately from parts conneXion, as well as a couple of Mundorf poly caps, not TOTL, just good ones to start with. Unfortunately I ought to have ordered four, I forgot the phono to line stage pair, but fortunately had a couple of nice poly caps from another pre-amp job, so used those instead. No issues whatsoever with my build, gorgeous kit! Over two years later it is still as silent as the grave at full volume, I popped in a couple of Psvane's fully matched TOTL 12AU7-T's from my previous TRI TRV-88SE amp, replacing the stock tubes quite soon after the build. The Psvane tubes are stunning, transparent from the very bottom to the very top, making for an incredibly insightful, neutral and alive preamplifier. If the TU8200DX is anything like that good, want! I love my headphone listening - I have a couple of dedicated set-ups - but if I can build a great amp that will run with my 106dB efficient 1968 Sansui SP300 speakers (interestingly, although they will run with a 2W valve amp (I've done it with a restore job last year) they are significantly better when using a recently restored Eidetic GB-1a with 150W available - AND have a great headphone amp, I'm in! I still have a used set of Psvane KT88-T's from that TRI amp available. My problem is that I will have to save more, because there is no doubt I will want the full upgrade kit and Lundahl trannies!


----------



## jerick70

UntilThen said:


> Nope that's not Odyssey. That Greek hero will be built in my Winter of 2021 - that's next month. Will use a silver solid aluminium chassis with Sowter output tranformers, Hammond power transformer and choke, Mundorf caps and Yamamoto sockets. Will use 6SL7 / 6SN7 drivers or a pair of Telefunken EL11. Power tubes are as varied as the TU-8200.
> 
> I did get a 300b amp a month ago, build by a seasoned local amp builder who's been doing it for 40 over years. Took him just one week to complete and I call it Destiny ! It's the cause of my disrupted sleeps for a month already and doesn't look like stopping. Whether with headphones or speakers, it is just heavenly.
> 
> That's the gold Destiny on the left and the amp builder's own KT88 set amp in triode mode on the right.


300bs are magical.  I owned a Woo WA-5 a few years ago and it was incredible.  I sold it because of the price of tubes for it.  I’m really wanting to get back into 300b amps the way you’re talking about it. . I’m really satisfied with my 8200dx though.


----------



## jerick70

sennsay said:


> I'd really like to buy one of those DX kits, it's next on the list. I really love my TU8500, I bought the resistor upgrade kit separately from parts conneXion, as well as a couple of Mundorf poly caps, not TOTL, just good ones to start with. Unfortunately I ought to have ordered four, I forgot the phono to line stage pair, but fortunately had a couple of nice poly caps from another pre-amp job, so used those instead. No issues whatsoever with my build, gorgeous kit! Over two years later it is still as silent as the grave at full volume, I popped in a couple of Psvane's fully matched TOTL 12AU7-T's from my previous TRI TRV-88SE amp, replacing the stock tubes quite soon after the build. The Psvane tubes are stunning, transparent from the very bottom to the very top, making for an incredibly insightful, neutral and alive preamplifier. If the TU8200DX is anything like that good, want! I love my headphone listening - I have a couple of dedicated set-ups - but if I can build a great amp that will run with my 106dB efficient 1968 Sansui SP300 speakers (interestingly, although they will run with a 2W valve amp (I've done it with a restore job last year) they are significantly better when using a recently restored Eidetic GB-1a with 150W available - AND have a great headphone amp, I'm in! I still have a used set of Psvane KT88-T's from that TRI amp available. My problem is that I will have to save more, because there is no doubt I will want the full upgrade kit and Lundahl trannies!


I’m pairing my 8500 with a Pass labs ACA amp right now.  Great pairing.  I run all my headphones from the speaker terminals. I built the ACA amp too.  I really like building audio equipment.  So satisfying and you get kit that hits way above its price range.  

sounds like a super fun build.  Sourcing all the parts is the best. I’m looking at either a custom Pass Labs amp for my next build, I already have the custom PCBs for the Pass Amp. Or the TU8600S for my next build.


----------



## UntilThen

I will have to ask Jules to build me a TU-8500 again.

Jerick you can build me a Pass Lab amp. 🤪


----------



## UntilThen

jerick70 said:


> 300bs are magical.  I owned a Woo WA-5 a few years ago and it was incredible.  I sold it because of the price of tubes for it.  I’m really wanting to get back into 300b amps the way you’re talking about it. . I’m really satisfied with my 8200dx though.



Well start with cheaper Gold Lion 300b tubes and progress to KR Audio 300 tubes. You don’t have to go Takatsuki straight away but knowing you, you will. 😋


----------



## jerick70 (May 21, 2021)

UntilThen said:


> I will have to ask Jules to build me a TU-8500 again.
> 
> Jerick you can build me a Pass Lab amp. 🤪


Sure.  I love building amps. This is the amp I’m using.  You can do monoblocks too.  Nelson Pass makes the most simple but best sounding circuits in the industry.  This $300 amp is a mini J2 in sound. So analogue and tube sounding.  I’ve owned a J2 and they are really close.  8 watts into 8 ohms.

https://diyaudiostore.com/products/amp-camp-amp-kit?variant=7072933085218

Here’s my stack:


----------



## jerick70

UntilThen said:


> Well start with cheaper Gold Lion 300b tubes and progress to KR Audio 300 tubes. You don’t have to go Takatsuki straight away but knowing you, you will. 😋


Yeah you know me too well….


----------



## sennsay

jerick70 said:


> I’m pairing my 8500 with a Pass labs ACA amp right now.  Great pairing.  I run all my headphones from the speaker terminals. I built the ACA amp too.  I really like building audio equipment.  So satisfying and you get kit that hits way above its price range.
> 
> sounds like a super fun build.  Sourcing all the parts is the best. I’m looking at either a custom Pass Labs amp for my next build, I already have the custom PCBs for the Pass Amp. Or the TU8600S for my next build.


I s'pose I could run a couple of resistors from the output terminals of the Eidetic amp and either have an external 6.5mm socket or build one into the amp for my Sennheiser HD540 Ref 1 600 ohm cans ..... 
I loved building the TU8500 pre-amp, took my time to trim the board cleanly where they were attached to each other, double checked positioning of each part and had no issues whatsoever ... I have built many kits over the years, yet the quality of this one is superb, everything soldered effortlessly and all holes lined up perfectly. I lined the resistor codes to match as well, symmetry. I did replace the simple phono earth screw - which was a right pain to use, especially if swapping decks or moving the pre-amp to a different system - with a proper earth post. Much better. 
 Steve Guttenberg liked the ACA as well.


----------



## sennsay

jerick70 said:


> Sure.  I love building amps. This is the amp I’m using.  You can do monoblocks too.  Nelson Pass makes the most simple but best sounding circuits in the industry.  This $300 amp is a mini J2 in sound. So analogue and tube sounding.  I’ve owned a J2 and they are really close.  8 watts into 8 ohms.
> 
> https://diyaudiostore.com/products/amp-camp-amp-kit?variant=7072933085218
> 
> Here’s my stack:


Mmm, if you replaced the red LEDs with blue ones, they could almost be a perfect match ... 
I see you use a DAP there, I often use my Questyle QP1R as a source, either from the 3.5mm analogue signal from the internal DAC using an AQ Big Sur cable, or run optical out to a Schiit Audio Modi Multibit DAC, AQ Carbon cable.


----------



## jerick70

sennsay said:


> Mmm, if you replaced the red LEDs with blue ones, they could almost be a perfect match ...
> I see you use a DAP there, I often use my Questyle QP1R as a source, either from the 3.5mm analogue signal from the internal DAC using an AQ Big Sur cable, or run optical out to a Schiit Audio Modi Multibit DAC, AQ Carbon cable.


Yes I agree.  The ACA was originally for running my Zu Omen IIs.  I wanted to do something a little different because everything is blue now-a-days.  It’s easily changeable though.

I’m using a Hiby R6 2020 > LO > Zu Audio Mission cable > TU-8500 > Pass ACA speaker outs > Dyson Audio speaker to 4 pin XLR cable > headphones.  It’s great little setup to chill with…


----------



## sennsay

jerick70 said:


> Yes I agree.  The ACA was originally for running my Zu Omen IIs.  I wanted to do something a little different because everything is blue now-a-days.  It’s easily changeable though.
> 
> I’m using a Hiby R6 2020 > LO > Zu Audio Mission cable > TU-8500 > Pass ACA speaker outs > Dyson Audio speaker to 4 pin XLR cable > headphones.  It’s great little setup to chill with…


Are you using some NOS bottles in the TU8500? Stock (I might presume not so, but you _might_ be) are ok to get started, nice with MP3 files but lack resolution and transparency, bass depth and definition etc. I doubt if mine have had 5 hrs on them, so they are kept as spares. I've read that RCA Clear Tops (ECC82) are fine in the pre-amp, though I find the Psvanes are so good that I'm not bothered to look at any others for now. Funds used elsewhere and all that.


----------



## nottheseapples

Effusion said:


> *Elekit TU-8200DX Impressions/Review*​
> ​ Background: The TU-8200DX is a speaker and headphone amplifier kit, designed by Mr. Fujita of Elekit Japan as an upgraded design, with new features, to their highly praised and regarded TU-879S kit.  For North American enthusiasts, the kit can be purchased directly from Victor Kung of VKMusic in Canada, which includes English instructions.  The kit currently runs $725 US for the "DX" version from Victor, which includes 4 Amtrans AMCO 104 PET capacitors as well as 4 Nichikon conductive polymer aluminum electrolytic capacitors.  There's also an option through VKMusic to add an additional Elekit PS-3249 USB DAC to the unit as well.
> 
> I had the pleasure of meeting Mr. Kung of VKMusic at the 2013 RMAF show and I'm really glad I was able to talk with him about his passion for DIY and the various kits as well as fully assembled products offered by him to the North America market and sourced from Elekit in Japan.  I have been interested in a few of Elekit's offerings in both the distant and more recent past, including the highly regarded TU-882, which uses one of my favorite signal miniature vacuum tubes, the 2c51/396a/5670.  Unfortunately I've never been able to audition the TU-882, so I can't comment on its sonics, but if you are interested here is a great review done a few years back by Skylab.
> ...



nice review! owned the tu-882, loved that amp!


----------



## jerick70

sennsay said:


> Are you using some NOS bottles in the TU8500? Stock (I might presume not so, but you _might_ be) are ok to get started, nice with MP3 files but lack resolution and transparency, bass depth and definition etc. I doubt if mine have had 5 hrs on them, so they are kept as spares. I've read that RCA Clear Tops (ECC82) are fine in the pre-amp, though I find the Psvanes are so good that I'm not bothered to look at any others for now. Funds used elsewhere and all that.


I use NOS and new production tubes.  I have NOS telefunken tubes in the 8500 right now.


----------



## UntilThen

I was using Philips Miniwatt 12au7 in my TU-8500.


----------



## sennsay

jerick70 said:


> I use NOS and new production tubes.  I have NOS telefunken tubes in the 8500 right now.


And what balance do they have to you? Neutrality, mid-warmth, warmer bass or not? Just curious. These tubes/valves are just as important in the input stages of the amp too. I had a Sonic Frontiers SFL-1 pre-amp here for a rebuild a little while back, and once serviced the tube that stunned me the most was my one and only Seimens Gold Pin 6922 (it had been used in a TRI CD player), transparency and speed so astonishing that if I ever find another one of those pre-amps I will use that tube before anything else. I have kept my Psvane KT88-Ts (Black Bottle) just for when I buy one of these TU8200 kits.


----------



## jerick70

sennsay said:


> And what balance do they have to you? Neutrality, mid-warmth, warmer bass or not? Just curious. These tubes/valves are just as important in the input stages of the amp too. I had a Sonic Frontiers SFL-1 pre-amp here for a rebuild a little while back, and once serviced the tube that stunned me the most was my one and only Seimens Gold Pin 6922 (it had been used in a TRI CD player), transparency and speed so astonishing that if I ever find another one of those pre-amps I will use that tube before anything else. I have kept my Psvane KT88-Ts (Black Bottle) just for when I buy one of these TU8200 kits.


I pair my tubes according to source and amp.  I really like warm / analog sound.  I used the Telefunken tubes because they even out the warmness of the ACA amp.  It’s quite warm.  I do like bass with a nice smooth presentation.  No fatigue.  

In my TU-8200 I like darker tubes. I use NOS mullards, new production Genlex golden lions and the like.


----------



## sennsay

jerick70 said:


> I pair my tubes according to source and amp.  I really like warm / analog sound.  I used the Telefunken tubes because they even out the warmness of the ACA amp.  It’s quite warm.  I do like bass with a nice smooth presentation.  No fatigue.
> 
> In my TU-8200 I like darker tubes. I use NOS mullards, new production Genlex golden lions and the like.


Ah yes, they are a bit like the Amperex Orange Globe 6922's I used in the Valhalla 2 I used to have, recommended by the Schiit team. They are certainly 'warmer' than the Psvane 12AU7-T's, though not as transparent or extended at both ends. I use my TU8500 with a restored and upgraded Eidetic GB-1a power amp running into extremely sensitive (some 106dB) 1968 Sansui SP300 speakers. And yes, although the Eidetic is a 150WPC+ power amp, it runs magnificently with the Sansui's, the big horn mid driver (per channel) and horn tweeters with 12" bass driver (these SP300's are 36kg each cabinet). The sheer living presence in the room, including images above and behind the speakers, is something I utterly love to bits. Music is ALIVE. I have driven them with a 2W valve amp before and they run fine, a 10W Pioneer amp (ok), my usual 50W homebuilt amp (very well indeed), but the Eidetic lives up to it's reputation and I will not part with it now. 
 I have also heard that RCA 6201 Black Plates are also very fine in this pre-amp. I still would love to built the TU8200!


----------



## Harmonique131

Hello to you all.

For more than two years now, I have been using an Elekit TU-8200DX with great musical pleasure. I love this amplifier. I use Tung-Sol 7581A and Psvane 12AU7-TII tubes which give wonderful musical results on my Totem Sttaf speakers.

But I wanted to try to use a power cable in combination with the Elekit that would magnify the musical qualities of this beautiful tube amplifier as much as possible, without spending too much money.

I chose to build the power cable with pure copper Viborg plugs (gold plated shuko and silver plated IEC) and a cable sold by the meter (I'm in France), brand Furutech TCS31.

At the beginning, the musical result was horrible ! I wondered if I had not spent money unnecessarily. But the sound changed a lot after about 50 hours, to stabilize around 100 hours of use. And the result is beautiful! The voices become as incarnated, carnal, the general tone is soft, the highs a little in retreat, but with matter and very rich in harmonic. The Elekit seems to go lower in the bass with this power cable. Finally, the sound image is magnificent, wide and deep.

This cable will not please the amateurs of dynamics and extreme transparency, but I do not think that the owners of this amp are in this category.

I only wanted to share my experience with the Elekit and this power cable. If this is of any interest to you, I am delighted. If not, don't worry, we can live without it, very well !

Sincerely yours.

Translated with www.DeepL.com/Translator (free version)


----------



## Effusion

Thank you @Harmonique131 for sharing your experience!  I agree the 8200DX is an amazing amp that pairs very well to all sorts of additional gear.  During my journey, I have found that power cables can make a huge difference compared to other changes and DIY has really amazing value, if done right.

Cheers to the 8200DX!


----------



## barbz127

I'm in the market for some bookshelf speakers for the 8200r, would anyone have any they can recommend?

Current front runner is the Zu audio omen bookshelf.

Thankyou


----------



## UntilThen

Zu Omen is a good choice but depends on how loud you want to listen and where you place your speakers. In this nearfield setup, I've used Axis LS28, VoiceBox S and Whaferdale Diamond 10.1. My Elekit TU-8200 drives them all very well.


----------



## barbz127

UntilThen said:


> Zu Omen is a good choice but depends on how loud you want to listen and where you place your speakers. In this nearfield setup, I've used Axis LS28, VoiceBox S and Whaferdale Diamond 10.1. My Elekit TU-8200 drives them all very well.


Thanks, all relevant info I failed to provide sorry

This won't be for nearfield, rather for a living room with a chair near by for headfi duties. Speakers will need to be close to the wall so sealed or front ported at my options.


----------



## UntilThen

@bcowen please stop me from buying this Elekit.... because I already have so many frigging tube amps !!! But this one is screaming, 'Buy Me' !!!

https://www.stereo.net.au/forums/to...th-full-fruit-including-lundhal-transformers/


----------



## UntilThen

barbz127 said:


> Thanks, all relevant info I failed to provide sorry
> 
> This won't be for nearfield, rather for a living room with a chair near by for headfi duties. Speakers will need to be close to the wall so sealed or front ported at my options.



This would have been perfect and would have been mine but I am waiting for Odyssey and he's taking his sweet time coming home.

https://www.stereo.net.au/forums/topic/348718-fs-zu-audio-omen-dirty-weekend-upgraded/


----------



## Ovide

I’m still very happy with my Elekit 8200. I run E80CC’s as well as NOS ECC82’s (Mullard/Philips/Valvo and Brimar). Power tubes that I have used are amongst others Osram KT66 Grey, early 1950’s Mullard EL37, Mullard EL34 (XF2, XF3 and XF4), RCA 6L6GC BP, GE 6L6GC, Sylvania 6L6GC. I like the fact that through tube rolling you can adjust the sound to fit with your headphones. The mid emphasis of the Mullard EL34’s for instance accommodate the Beyer T1.1 very well.

I have a substantial collection of Philips 4699 metalrim tubes that I would like try out as well. Has anyone tried these in their Elekit yet?


----------



## Ovide

Nobody using the Philips 4699 with EL34 adapters?


----------



## UntilThen

My TU-8200 still under repair. Otherwise I will be tube rolling


----------



## Ovide

That sounds quite serious. I hope not due to tube rolling. Have you ever tried the 4699 met rim in the Elekit? It’s supposed to be even better than Mullard EL34.


----------



## UntilThen

I was using a NOS NIB pair of Sylvania 807 when the left tube go up in flames and took out the TU-8200. A guy I know is repairing it now but getting parts in this Covid times requires patience. I've not use 4699 but I have used Philips Miniwatt 6CA7 xf2 double O getters and RFT EL34. A seller I know has Philips Miniwatt 6CA7 double D getters brown base and also the metal base for me but I have put on hold anymore tubes buying until I get my custom KT88 / EL34 set amp. That is coming soon from Sweden.


----------



## aedaza

Hi allI bought 2 pairs of 807s with adapters from a reputable seller. With both pairs, after a couple of minutes, sound goes out in one channel and the LED turns orange. Turn off the Elekit, change tubes and all is well. That happened a couple of times. Oddly with 5933 tubes it works quite well! Any guess?


----------



## UntilThen

aedaza said:


> Hi allI bought 2 pairs of 807s with adapters from a reputable seller. With both pairs, after a couple of minutes, sound goes out in one channel and the LED turns orange. Turn off the Elekit, change tubes and all is well. That happened a couple of times. Oddly with 5933 tubes it works quite well! Any guess?



When that happens it’s a warning and I think you shouldn’t continue to use those 807.

Even though other earlier owners reported that it’s ok to use 807 in Elekit TU-8200, I’m not a 100% convinced, especially with what happens to my amp and these warnings signs on yours.


----------



## Ovide

UntilThen said:


> Even though other earlier owners reported that it’s ok to use 807 in Elekit TU-8200, I’m not a 100% convinced, especially with what happens to my amp and these warnings signs on yours.


Thx for the heads up. I was about to buy a couple of ceramic VTS-25 but will rethink this now.


----------



## aedaza

UntilThen said:


> When that happens it’s a warning and I think you shouldn’t continue to use those 807.
> 
> Even though other earlier owners reported that it’s ok to use 807 in Elekit TU-8200, I’m not a 100% convinced, especially with what happens to my amp and these warnings signs on yours.


Yeah I haven't tried to use them more. On the other hand, the 5933 sound and work just fine! What is really happening to those 807s and the amp? How does that protection works with the LED turning orange?


----------



## Ovide

I think that the fet’s blow when the light turns orange. I have several fet’s in reserve, just in case. But I think it is good practice to first test your tubes before trying them out in the Elekit.


----------



## Effusion

I've used dozens of 807s in the 8200 over the years, including ceramic ATS-25s, without issue.  I have also blown two FETs thus far, knock on wood!  On the DX version, the light always turned purple I believe when the FETs blew (it's been awhile).  Both times the tubes were bad, with one blowing while running in the amp!  The newer R version has protections built-in, so this may be where the orange light and sound stopping, without blowing a FET comes in.  @aedaza, do you happen to have the 8200R?

Initially I was unaware of the 807 type working in the 8200, but I found a few meet/show pictures of Victor's early on where he was running them and he told me they were okay to use in the amp.  I've enjoyed them quite a bit since, especially the ATS-25s, but often find them lacking the finesse of certain other NOS types, however those at much higher prices.  They do however usually sound much better than many others I have, often having a nice in-between sound.

One issue I ran into is that US 807s tend to have a bigger top pin than their European counterparts.  I actually have 3 sets of adapters now; some fit the US snugly, but are loose on the Europeans (I only use them if they are snug), and others that fit the Europeans snugly, but won't even begin to fit over the tip of the top pin on the US ones.  I'd have to count, but I think I have around 70 or so 807s at this point, all sorts of manufactures/variants, smoked, ceramic, hand-painted, etc.

I'm no expert, but Victor should be able to address any concerns regarding the 807s and/or technical questions of their use in the amp, R and pre-R, through Mr. Fujita.

I hope this helps!  Keep on rocking those 8200s!


----------



## aedaza

Thanks @Effusion ! Actually I have the DX version. Yeah funny thing that my LED turned orange instead of purple. Do you guys think that FETs in my amp could be already out of spec? The amp has been working fine, but I don't know if the tubes did any wrong to the amp. Might be that it tuned orange meaning that the FETs did not blow up in my case?


----------



## Effusion

You're very welcome!

Yes, that is strange, but makes some sense since the amp is still able to run.  When I blew both of mine, the amp no longer worked in the particular channel where the FET went out, so that may explain the orange instead of purple light.  I did some quick searches of the manual and some other forums, but unfortunately at no avail.

Maybe ask Victor, user vkung here, and see what he says?  Is the quality of the sound any different?  Any hums or cracks/pops, etc., now?  If not, you probably just got really lucky!  It is a good idea to have a few FETs on hand though and also to be able to replace them if you tube roll a lot.  I've been lucky to only have two bad tubes out of hundreds thus far, but when one goes and puts the amp out for a bit of time, it's really a bummer.


----------



## aedaza

Thanks pal! Good advice... Do you know where I can source those FETs? Better to have some spares


----------



## Effusion

Sure thing, you're very welcome!  Always best to be prepared!

I got mine from Victor, but I believe they are common enough to find easily online.  However, unfortunately I'm unsure of the exact part number at the moment.  It might be best to ask Victor, as not only would he know, he might have some to sell or know where to get them depending on your location.  You could also do a search on this thread, as I'm pretty sure someone probably linked to them at some point.


----------



## smodtactical (Aug 21, 2021)

Passion for sound likes mainline more than TU8200 with lundahl Trafos. Anyone else do this comparison ? I am a bit surprised, thought the upgraded 8200 would have taken it. I Think he just likes the richer sound of the mainline.


----------



## barbz127

The mainline has a special kind of bass that I've found rare in tube amps.


----------



## Levanter

Been searching for a tube amp and this caught my interest. I like the smaller form factor too. 
Anyone has a similar sized DAC which pairs well? And is it safe to place the tube amp on top of the DAC?


----------



## Galapac (Nov 25, 2021)

Levanter said:


> Been searching for a tube amp and this caught my interest. I like the smaller form factor too.
> Anyone has a similar sized DAC which pairs well? And is it safe to place the tube amp on top of the DAC?


Your post was awhile ago so not sure if you got your answer.
I pair mine with a Topping D70 and it pairs quite well.
I also have the option of going direct from my DAP because of the 2 inputs.


----------



## Galapac (Nov 25, 2021)

I just finished my TU-8200R DX from diyaudiostore.com with Lundahl transformers and I am quite pleased with the results.
Running mine on Triode mode with a pair of Genelex KT-88s and a pair of Shuaguang ECC82s and the sound is very dynamic and full sounding through the spectrum. I also had mine powder coated in red to stand out from the usual.
Great amp for any DIYer.


----------



## UntilThen

Agree that the Elekit TU-8200 is a great sounding amp at an affordable price. I experimented with lots of power tubes with it and am very impressed. Only sold it recently because I wanted to keep the tube amps count to 3.


----------



## Galapac

I have read most of the pages in this thread regarding upgrades to the TU-8200R but maybe someone can clarify for me.
I have the latest TU8200R DX from diyaudiostore.com which has the Lundahl transformers and I want to try E80CC tubes I place of the 12AU7s.
I have searched on this site and others and I am not 100% clear in what I need to swap out for parts.

I have surmised they at the least I need to replace the bridge rectifiers in D5-D7 with something like these: https://www.digikey.com/en/products/detail/DF210-G/641-1343-5-ND/2074808

Is there anything else I need to consider before using the E80CC tube type?


----------



## Galapac

Galapac said:


> I have read most of the pages in this thread regarding upgrades to the TU-8200R but maybe someone can clarify for me.
> I have the latest TU8200R DX from diyaudiostore.com which has the Lundahl transformers and I want to try E80CC tubes I place of the 12AU7s.
> I have searched on this site and others and I am not 100% clear in what I need to swap out for parts.
> 
> ...


I think I have my answer here from Dimu and only need to upgrade the rectifiers and as long as I only pair the E80CC with 6L6GC I shouldn’t have problems with the power transformer overheating.

Post in thread 'Elekit TU-8200 DX Headphone/Speaker Amp Review'
https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-12683344


----------



## ColdsnapBry

Do I have to do anything to the 8200 for a good headphone out? I'll use it only as a headphone amp with ZMF/Sennheisers.


----------



## UntilThen

Nope just plug your headphone in. The amp is very quiet and sound great.


----------



## driftingbunnies

Anyone have good recommendations for new production tubes? I've been recommended to go NOS for input tubes and then new production should be fine for power tubes. The prices and availability of the tubes that were recommended when this thread started are so drastic that some recommendations don't make as much sense anymore. Thanks!


----------



## UntilThen

Try Psvane KT88 Tii or Shuguang Treasures KT88-Z. Psvane is better but just.


----------



## Galapac

I prefer the Tung-Sol new production over any of the Chinese tubes and I have tried the KT-88 Gold Lion, the KT88 Treasures.
Check out the new 7581A Tung-Sol reviews online, it's like a beefed up 6L6GC, but with more depth and balance.


----------



## Harmonique131

Good evening.

For those of you who like warmth of voices and rich harmonic timbres, with a lot of sweetness, I obtained a wonderful reproduction with two tubes of current design:
- The TAD 6L6WGC-STR Blackplate GE style :
https://www.tubeampdoctor.com/en/6l6wgc-str-blackplate-ge-style-tad-premium-matched?number=RT812

- and the 12AU7 Full Music :
https://www.tubeampdoctor.com/en/tj-full-music-12au7?number=FM-12AU7-MP

I give European links because I am in France, but I imagine that they can also be found elsewhere (the TAD site is very serious and makes a good pairing of tubes).

A wonderful symbiosis between these two tubes and a really excellent musical reproduction! (The Tung-Sol 7581A can't beat the warmth on the voices and the refinement of the timbres. And the marriage with the 12AU7 Full Music is not magic).

Musically from France.


----------



## Galapac (Dec 11, 2021)

That is why it is _all_ subjective and I think when someone asks what new production tubes are best, the response should be, what types or genres of music do you listen to the most?

I find that different combinations of tubes work best in certain genres over others.
That may be why I prefer Tung-Sol for new production over the Chinese counterparts as they synergize well with my preference for rock and heavy metal music.

They are also innovating new designs in their tubes.
Have you seen the new Tung-Sol 6L6G? It’s a new coke bottle shape and has a huge soundstage in my TU-8200R.
Nice bonus blue glow as well. 😎


----------



## Harmonique131

Hello Galapac.

Thank you for your testimony which I absolutely share. Indeed, certain associations of tubes allow a more or less successful marriage. Everything will depend on the desired result and the style of music we listen to. I do not know the new 6L6 of Tung-Sol, I thank you very much for this information. 

Indeed, the 7581A Tung-Sol is a wonderful tube and it goes very well with the Sylvania GB 5814A. The result is very good, extremely different from the TAD tubes, with a lot of transparency, a large soundstage, a nice holographic precision and very pure timbres, but much less rich in harmonics than with the TAD tubes. The dynamics and the bass are also good. 

No set of tubes between these two is superior to the other, it is just a matter of taste and musical style. For my part, I sometimes use one or the other depending on the style of music I want to listen to, even if my preference is clearly for the TAD and Full Music. 

One more reason to appreciate strongly this wonderful little amplifier, which allows to find the subtle balance between the musical style and the musical result which will then strongly depend on the tubes used. 

Sincerely from France.


----------



## Galapac

Hey @Harmonique131, Thanks for the lead on the Sylvania GB 5814A, I have not tried that tube yet and will give it a go when I have the chance.


----------



## driftingbunnies

Thanks @Harmonique131 and @Galapac ! I'll take a look at those suggestions. Have any of you tried KT88's with the 8200? I know Victor has said that the amp was designed with 6L6GC in mind but I've been getting a few KT88 recommendations since this amp should be compatible.


----------



## Galapac

How much are you willing to pay for a pair of E80CC tubes? This is crazy…

https://www.ebay.com/itm/265463526360?hash=item3dcedbf3d8:g:HI0AAOSw305hwfou


----------



## jonathan c

Galapac said:


> How much are you willing to pay for a pair of E80CC tubes? This is crazy…
> 
> https://www.ebay.com/itm/265463526360?hash=item3dcedbf3d8:g:HI0AAOSw305hwfou


Agreed !!...is seller a relative of wege_high_tubes?…Does larceny run in the family?…


----------



## Galapac

jonathan c said:


> Agreed !!...is seller a relative of wege_high_tubes?…Does larceny run in the family?…


This is not the seller…he started the auction around $89.00 and these fools are bidding it to the heavens. I’m watching this one to see if they pull their bids…there has been a lot of abuse of this lately on auctions.


----------



## lostrockets

What will changing the caps and transformer do to the sound? Some reports ive read say the change is subtle while other say its more significant. Curious what your experience has been and what you changed


----------



## lostrockets

Galapac said:


> That is why it is _all_ subjective and I think when someone asks what new production tubes are best, the response should be, what types or genres of music do you listen to the most?
> 
> I find that different combinations of tubes work best in certain genres over others.
> That may be why I prefer Tung-Sol for new production over the Chinese counterparts as they synergize well with my preference for rock and heavy metal music.
> ...


Hows the coke bottle shape sound different from the smaller shape?


----------



## Mercuttio

lostrockets said:


> Hows the coke bottle shape sound different from the smaller shape?


They sounded the same to me. Not worth the premium, frankly.


----------



## Galapac

Mercuttio said:


> They sounded the same to me. Not worth the premium, frankly.


I would agree that the sound isn't that much different but I enjoy the glow. YMMV.


----------



## lostrockets

Anyone tried or know if its possible to use 6sn7gtb with an adapter in place of the 12au7?

What about el84 with an adapter in place of 6l6?


----------



## Galapac

Yes you can use 6SN7s in the Elekit TU-8200, but I had beefed up my amp with 2 amp bridge rectifier diodes so I could also use other tubes as well.
https://www.digikey.com/en/products...808?s=N4IgTCBcDaIGwBYCMBaJBmB6UFYUDkAREAXQF8g

I use 6SN7s with 6L6GCs only as that keeps the heat down. I’m afraid to push it any further as I wouldn’t want to damage the transformer.
This setup I use stays cool and allows me to use my 6SN7 tubes.

Got these adapters but Deyan can make you a pair too.
https://www.ebay.com/itm/193442652471


----------



## lostrockets

Galapac said:


> Yes you can use 6SN7s in the Elekit TU-8200, but I had beefed up my amp with 2 amp bridge rectifier diodes so I could also use other tubes as well.
> https://www.digikey.com/en/products...808?s=N4IgTCBcDaIGwBYCMBaJBmB6UFYUDkAREAXQF8g
> 
> I use 6SN7s with 6L6GCs only as that keeps the heat down. I’m afraid to push it any further as I wouldn’t want to damage the transformer.
> ...


nice! hows the sounds compared to 12au7? and is the bridge rectifier required to use the adapter?


----------



## Galapac

To tell you the truth, I don’t hear much of a difference between the 6SN7 and 12AU7 in this amp.
Others may but I got the adapters because I had a lot of 6SN7s lying around and thought it would be fun to tube roll them in for variety.
I have only had the adapters for about a week so I am still experimenting.
I don’t think the bridge rectifier is required but it does give you a bit more headroom with regards to power.


----------



## Mercuttio

Given recent events, I'm starting to become quite concerned that my tube supplies are going to dry up. At the moment, I only really buy JJ stuff, from Slovakia. I have noticed now that those too are very difficult to find from any of the readily available sources. I have enough to probably last another year, but it is a weird little reminder of greater events taking place. Has anyone else noticed this, and what are folks who use mostly new stock tubes doing to mitigate it?


----------



## lostrockets

Galapac said:


> To tell you the truth, I don’t hear much of a difference between the 6SN7 and 12AU7 in this amp.
> Others may but I got the adapters because I had a lot of 6SN7s lying around and thought it would be fun to tube roll them in for variety.
> I have only had the adapters for about a week so I am still experimenting.
> I don’t think the bridge rectifier is required but it does give you a bit more headroom with regards to power.


I went ahead and contacted elekit about adapters and they said it wasnt recommended so i wont be using then on my amp but good its working out for yours!


----------



## lostrockets

Mercuttio said:


> Given recent events, I'm starting to become quite concerned that my tube supplies are going to dry up. At the moment, I only really buy JJ stuff, from Slovakia. I have noticed now that those too are very difficult to find from any of the readily available sources. I have enough to probably last another year, but it is a weird little reminder of greater events taking place. Has anyone else noticed this, and what are folks who use mostly new stock tubes doing to mitigate it?


I also read that there’d be a shortage of new production russian…and curious if youve considered nos? I was initially against them but my experience has been positive 4 years in, since i first tried them out. 

Theres plenty of nos tubes available for the elekit, not only on ebay and tube sellers like jim mcshanen, jesse brent vintage tube supply at reasonable prices thatll last you years


----------



## Mercuttio

lostrockets said:


> I also read that there’d be a shortage of new production russian…and curious if youve considered nos? I was initially against them but my experience has been positive 4 years in, since i first tried them out.
> 
> Theres plenty of nos tubes available for the elekit, not only on ebay and tube sellers like jim mcshanen, jesse brent vintage tube supply at reasonable prices thatll last you years


I have done some NOS in the past, but the prices have spiraled so high. I actually liked the basic JJ tube setup more than the more expensive Tung-Sol stuff from Russia. I think mostly I've been expecting to spend around $60 on a full restock of tubes for the unit, but now I'm seeing that price go to $90 on my most recent restock, to over $130 if what I'm looking for is in stock. 

What should I expect to pay for NOS tubes, and what is the lifespan like? I run this thing 8+ hours a day 5 days a week. The JJ tubes generally give me a year or so of service.


----------



## Galapac (Mar 14, 2022)

Mercuttio said:


> Given recent events, I'm starting to become quite concerned that my tube supplies are going to dry up. At the moment, I only really buy JJ stuff, from Slovakia. I have noticed now that those too are very difficult to find from any of the readily available sources. I have enough to probably last another year, but it is a weird little reminder of greater events taking place. Has anyone else noticed this, and what are folks who use mostly new stock tubes doing to mitigate it?


Read about it all here:

https://www.gearnews.com/mike-matth...ix-says-no-more-russian-vacuum-tubes-in-2022/

That means all tubes are going up, including Slovak, Chinese, and NOS tubes as Russia was a huge supplier over several brands.

NOS might be higher priced than JJ tubes but they also may last you longer, if you can believe that, as long as they are fairly unused or true NOS.
If you never tried I suggest you do and you may like the sound a lot better.

10 X 5 X 52 = 2,600 hours which is really not a lot for a tube. The new production tubes should last at least 5,000 hours but unfortunately many don't.


----------



## Mercuttio (Mar 14, 2022)

Galapac said:


> Read about it all here:
> 
> https://www.gearnews.com/mike-matth...ix-says-no-more-russian-vacuum-tubes-in-2022/
> 
> ...


Huh, good to know on the hours. I may be basing a lot of my projections on life on sets of Tung Sol I had go out after around a year. I haven't had a JJ tube fail me yet, though. Perhaps those will be better.

I just looked at my above comment, and I see I wrote "The JJ tubes generally give me a year or so of service." I mis-typed- I meant Tung Sol here.


----------



## lostrockets

Mercuttio said:


> I have done some NOS in the past, but the prices have spiraled so high. I actually liked the basic JJ tube setup more than the more expensive Tung-Sol stuff from Russia. I think mostly I've been expecting to spend around $60 on a full restock of tubes for the unit, but now I'm seeing that price go to $90 on my most recent restock, to over $130 if what I'm looking for is in stock.
> 
> What should I expect to pay for NOS tubes, and what is the lifespan like? I run this thing 8+ hours a day 5 days a week. The JJ tubes generally give me a year or so of service.


i hear you and thats some heavy use! maybe consider asking a vendor if you buy a lot of tubes for a bulk discount ?


----------



## Mercuttio

Hey so this is a REAL stupid question, but- 
If I don't have speakers connected to the back of this unit, and it's on without a headphone connected to it, could that potentially damage it? Say, using it as JUST a headphone amplifier? I've always heard people talk about running units without a load attached as being bad.


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## jerick70 (Mar 15, 2022)

Mercuttio said:


> Hey so this is a REAL stupid question, but-
> If I don't have speakers connected to the back of this unit, and it's on without a headphone connected to it, could that potentially damage it? Say, using it as JUST a headphone amplifier? I've always heard people talk about running units without a load attached as being bad.


I don’t think so. I leave my solid state Burson Conductor 3XR on all the time and have never had an issue.  

Now tube headphone amps are a different story.  I wouldn’t recommend leaving one on because if one of the tubes shorts or blows when you’re not there it could burn down your house.  It’s not going to damage your amp if there isn’t a load on it though.


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## lostrockets

was listening to some liszt today and noticed some distortion. 

its only audible on some of the busier sections of some songs like "Années de pèlerinage I, S. 160: No. 6, Vallée d'Obermann"  but it sounds pretty bad when it happens.

 anyone else know what could be causing it? 

obviously if i lower the volume it goes away. 

not sure if its the elekit or the tubes or the speakers or something else. 

any ideas what it could be ?


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## jerick70

lostrockets said:


> was listening to some liszt today and noticed some distortion.
> 
> its only audible on some of the busier sections of some songs like "Années de pèlerinage I, S. 160: No. 6, Vallée d'Obermann"  but it sounds pretty bad when it happens.
> 
> ...


I’ve had issues like this with certain recordings.  But it’s really a crap shot to guess.  Post your whole audio chain including tubes, interconnects, and headphone cable + headphones.


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## lostrockets (Apr 2, 2022)

jerick70 said:


> I’ve had issues like this with certain recordings.  But it’s really a crap shot to guess.  Post your whole audio chain including tubes, interconnects, and headphone cable + headphones.


I figured it out. I tried first replacing the drivers (mullard nos with new prod gold lions) helped a little. Then tried replacing gold lion kt66 (which i enjoy for electronic music thanks to the extra bass) with tung sol 7581s and this helped as well. What eliminated the distortion completely was switching from triode to UL!


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## Galapac

I prefer pentode mode myself.
Triode was a bit “soft“ for my tastes In terms of power wheras pentode seems ”bolder”, if that makes sense.


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## lostrockets

Galapac said:


> I prefer pentode mode myself.
> Triode was a bit “soft“ for my tastes In terms of power wheras pentode seems ”bolder”, if that makes sense.


Definitely a different sound, what tubes are you using with pentode?


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## Galapac

lostrockets said:


> Definitely a different sound, what tubes are you using with pentode?


I mainly use 6L6GC/EL34 varieties with E80CCs up front but I moved my amp to take the E80CCs as they require a bit more power.
The amp runs cool to the touch so I have no issues and have been running this setup for about 5 months now.
My favorite 6L6GC/EL34s are:
Svetlana Winged ==C== EL34 original, not the rebrand.
RCA 6L6GC black plate
Sylvania 6L6GC

Here is a link where I shared what I did to use EL80CCs and 6SN7s.

Post in thread 'Elekit TU-8200 DX Headphone/Speaker Amp Review'
https://www.head-fi.org/threads/elekit-tu-8200-dx-headphone-speaker-amp-review.722633/post-16850879


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## lostrockets

anyone compared the winged c to any other el34s or even new production? how about the nos 6L6 to new production?

got some 5881s on the way to try out. also looking for some nos 7581s.

so far my favorite are nos amperex 12au7s with gold lion kt77s


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## Dimu

So I finally decided to swap output transformers in my amp which I got from Victor more than a year ago. Really like the sound! If money is no object this one is a recommended upgrade. Also parasitic noises went down to next to nothing. And it fits nicely with my big power transformer.

Separate thanks to Victor for using high quality wire in the transformer upgrade kit. It made a difference.

I've been enjoying this amp for years and I am not planning to stop, it is just awesome! In fact I have a sealed backup unit sitting in the closet


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## UntilThen

I see you are using TFK EL12 spez.

I am a fan of using Telefunken EL12 spez in Elekit TU8200. I have 3 pairs of those bought in new original TFK boxes.

Though I have other good tubes such as GEC KT88 and Mullard EL34 double D getters and Tung Sol  6550 1960s, I still return to the EL12 spez very often.


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## Galapac (May 24, 2022)

Dimu said:


> So I finally decided to swap output transformers in my amp which I got from Victor more than a year ago. Really like the sound! If money is no object this one is a recommended upgrade. Also parasitic noises went down to next to nothing. And it fits nicely with my big power transformer.
> 
> Separate thanks to Victor for using high quality wire in the transformer upgrade kit. It made a difference.
> 
> I've been enjoying this amp for years and I am not planning to stop, it is just awesome! In fact I have a sealed backup unit sitting in the closet


Wow! Long time, no post.
Glad to see you are still among the living.
How would you compare the performance now compared to pre Lundahl?

I did that upgrade first when I bought mine along with your recommended bridge diode upgrade to use the E80CCs and love my TU-8200 with different EL34/6L6GC combinations.


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## Galapac

UntilThen said:


> I see you are using TFK EL12 spez.
> 
> I am a fan of using Telefunken EL12 spez in Elekit TU8200. I have 3 pairs of those bought in new original TFK boxes.
> 
> Though I have other good tubes such as GEC KT88 and Mullard EL34 double D getters and Tung Sol  6550 1960s, I still return to the EL12 spez very often.


Any other recommendation for EL12 spez or is that THE tube to have in that class?
I see also Tungsram in EL12 but not sure of their performance.

I also just built the TU-8600S and using that with WE 300Bs and that is one sweet amp but that is for another thread.


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## Dimu

Yes I like EL12 a lot, even though it is not a fit for this amp strictly looking at the datasheet. But it sounds great and I have not had any trouble with it yet. My other big favorite is GEC TT21 which is similar to KT88. But I had trouble with a pair of TT21 after a while. GEC KT66 is very nice too. I don’t like EL34 sound, 6L6 sounds better to my ear. Never tried TungSol but I would imagine I would like it. Tried some other tubes but nothing else is noticeably better than 6L6. So EL12, TT21/KT88 and KT66 are my favorites. And I don’t buy any tubes that are not at least 40 years old, most of my EL12 are from 1954. EL12 is a good thermal fit for this amp, it runs much cooler than with big tubes like TT21.

More important than output tube is E80CC input tube. I would take E80CC with 6L6 over any output tube with 12AU7. And as you can see in the pictures I power the whole thing from a beefed up transformer (not just higher current rating but bigger magnetic core) with additional caps for smooth power delivery with ample on-demand capacity. And all other components are upgraded including all caps, almost all resistors, and the pot. And soldered with lots of lead and silver throughout.

I mostly use the amp with Schiit Gungnir Multibit with USB buffer. And 8500 with Mullard 12AT7 in between, cranked up to boost second harmonic. When I use turn table it is hooked up via 8500 too which has significantly upgraded phono section.


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## Dimu

Galapac said:


> Wow! Long time, no post.
> Glad to see you are still among the living.
> How would you compare the performance now compared to pre Lundahl?
> 
> I did that upgrade first when I bought mine along with your recommended bridge diode upgrade to use the E80CCs and love my TU-8200 with different EL34/6L6GC combinations.


I think Lundahl is an improvement, I am definitely keeping mine. It was just about the only stock component I had left in my amp- everything else is not what came in the kit from Japan. I know Victor had worked a lot on making it happen, he tried different prototypes before he finally got it working well. And then he did this great job of figuring out a bracket, PCB and good quality wires. 

I travelled a lot over last couple years so spent little time near the amp and did not have a chance to upgrade transformers until today. Actually I opened it up to deal with D7 rectifier problem and at the same time decided to throw in the transformers. If you check the pictures you will see I mounted it differently than Victor’s pictures suggest, I did that in order to minimize cable lengths. So my left transformer is oriented same way as right so that secondary is facing backwards.

As for D7 I have ordered an 8 amp part to try because my 3 amp part does not seem to be too happy after a while.


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## UntilThen

Galapac said:


> Any other recommendation for EL12 spez or is that THE tube to have in that class?
> I see also Tungsram in EL12 but not sure of their performance.
> 
> I also just built the TU-8600S and using that with WE 300Bs and that is one sweet amp but that is for another thread.



I have not tried EL12 without the top anode cap.

I have tried Radiotron 807 which is good but not as good as EL12 spez.

Woo Audio offered to make the Teflon adapters for me and I might consider it because their adapters are just superb.


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## Dimu

UntilThen said:


> I have not tried EL12 without the top anode cap.
> 
> I have tried Radiotron 807 which is good but not as good as EL12 spez.
> 
> Woo Audio offered to make the Teflon adapters for me and I might consider it because their adapters are just superb.


You cannot just stick tubes in without checking datasheet for compatibility. EL12 without top anode is not rated for anode voltage produced by 8200. EL12 spez has much higher voltage rating which is compatible with the amp. The problem with it is oscillations at around 1MHz. I’ll play with it to see if I can suppress it because other than that it is a really great match for the amp.


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## jerick70 (May 25, 2022)

EL12 looks interesting.  I may try them, but I’m super happy with my Tungsol 7581As and Siemens E80CCs.

If I was going to spend more money on tubes, I think I would build the 300b amp and get some top end 300b tubes.


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## UntilThen

Dimu said:


> You cannot just stick tubes in without checking datasheet for compatibility. EL12 without top anode is not rated for anode voltage produced by 8200. EL12 spez has much higher voltage rating which is compatible with the amp. The problem with it is oscillations at around 1MHz. I’ll play with it to see if I can suppress it because other than that it is a really great match for the amp.



Yes I’m aware of that. That’s why I have stayed off EL12 but kept with EL12 spez.

In any case, EL12 spez is custom build for my tube amp and that’s not an Elekit.


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## Dimu

Dimu said:


> You cannot just stick tubes in without checking datasheet for compatibility. EL12 without top anode is not rated for anode voltage produced by 8200. EL12 spez has much higher voltage rating which is compatible with the amp. The problem with it is oscillations at around 1MHz. I’ll play with it to see if I can suppress it because other than that it is a really great match for the amp.


Checked those oscillations and confirmed that with Lundahl, E80CC and EL12 spez there are no high frequency oscillations. The only signals I see at 500KHz and above are present with amp disconnected from power, so these are induced from external fields.


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## sennsay

Dimu said:


> Yes I like EL12 a lot, even though it is not a fit for this amp strictly looking at the datasheet. But it sounds great and I have not had any trouble with it yet. My other big favorite is GEC TT21 which is similar to KT88. But I had trouble with a pair of TT21 after a while. GEC KT66 is very nice too. I don’t like EL34 sound, 6L6 sounds better to my ear. Never tried TungSol but I would imagine I would like it. Tried some other tubes but nothing else is noticeably better than 6L6. So EL12, TT21/KT88 and KT66 are my favorites. And I don’t buy any tubes that are not at least 40 years old, most of my EL12 are from 1954. EL12 is a good thermal fit for this amp, it runs much cooler than with big tubes like TT21.
> 
> More important than output tube is E80CC input tube. I would take E80CC with 6L6 over any output tube with 12AU7. And as you can see in the pictures I power the whole thing from a beefed up transformer (not just higher current rating but bigger magnetic core) with additional caps for smooth power delivery with ample on-demand capacity. And all other components are upgraded including all caps, almost all resistors, and the pot. And soldered with lots of lead and silver throughout.
> 
> I mostly use the amp with Schiit Gungnir Multibit with USB buffer. And 8500 with Mullard 12AT7 in between, cranked up to boost second harmonic. When I use turn table it is hooked up via 8500 too which has significantly upgraded phono section.


Interesting .... so what constitutes your 'significantly upgraded' phono section, Dimu? My own TU8500 has the 'standard' full upgrade kit, resistor pack plus the upgrade op-amps and two polypropylene coupling caps to the line stage, it's a good phono stage, but not fabulous, I prefer the line stage with Psvane 12AU7-T tubes and two Mundorf polypropylene caps, transparency IS fabulous! Top to bottom. If I can improve the phono stage then I would like to do so. Cheers.


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## kartk

Updated TU-8200 with some suggested mods on diyaudio, higher value filter cap. Upgraded oscon caps for bias reference, higher value cap for heater voltage.. Headphone out is dead silent, and even speaker out seems to have lower noise floor. It sounds way more cleaner. Using Brimar CV4003, Tungsol 5881 in Triode mode.
This is an amazing amp for such small form factor. Looking forward to use E80CC tubes as driver now with next set of mods.


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## SemiAudiophile

Anyone know what the power rating is out of the headphone out? 

I remember this being able to drive low impedance Grados and high impedance Senn HD650 beautifully. But trying to figure out if it will be powerful enough to drive hungry planars like HiFiMan HEKV2 or Susvara.


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## vkung

SemiAudiophile said:


> Anyone know what the power rating is out of the headphone out?
> 
> I remember this being able to drive low impedance Grados and high impedance Senn HD650 beautifully. But trying to figure out if it will be powerful enough to drive hungry planars like HiFiMan HEKV2 or Susvara.


No issue ...


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## thebigcanman

No idea of the rating but it had absolutely no issues with my HD800 when I had the setup


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## Sonic Defender

How loud would you people say you were listening, and to what style of music? The other member may listen louder than you and to different music that may be more demanding to reproduce.


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## thebigcanman

I listen to a wide variety of music. Never had to turn the amplifier up very loud. It was a superb pairing with the HD800 absolutely gripped it


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## Giru

Heard this amp last night (It was the 8200R with Lundahl OPTs, upgraded components and silver solder; Tung Sol 7581A driven by NOS Brimar 13D5). Dang! This amp is a solid piece of kit! It blew away the stock Feliks Euforia anniversary that I had actually gone to audition. I mean sure it's not a fair comparison but I could make out the difference on almost every attempt with my R70X. And to think this is a speaker amp and not even a dedicated headphone amp😯

Seriously considering getting a kit. Althought with all the upgrades and tubes (and not to mention the effin 77% customs duty🤬) the cost should be no less than the Feliks.


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## UntilThen

The 8200 is the brainchild of Odyssey.


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## Giru

The thing that impressed me most was how incredibly powerful and dynamic it was whilst being dead silent. The background was pitch black. Quite uncanny for a headphone amp let alone for a speaker amp. One can easily mistake it for a great ss amp if not for the warmth.

The Euphoria was only okayish and sounded a little thin in comparison, maybe a bit weak too. Bass depth was a bit better and I could feel the sub-bass on certain tracks however the sheer slam of the elekit was unmistakable. 

No doubt one of the best tube amps I've heard in a long time. Serious FOMO happening😣


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## UntilThen

Get it.  When things were less complicated and less expensive for me.


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