# Nobsound NS-08E also know as Nobsound 6J9 hybrid tube amp



## Headphone4Life

I've looked for a thread about this amp and didn't find one so I wanted to start one.

This is a very cheap hybrid tube amp at around $50 but don't let that fool you because its a nice little amp. Compared to my Schiit Vali I think it adds a little more in SQ while being as powerful. At 1100mW (32ohm) it has plenty of power to push most headphones and sound really nice with HE-400i and Sony Z7. I was thinking the tubes wouldn't play much of a part in this amp but I was wrong, they add a good bit of warmth and color that sounds quite good. You get the power of a solid state amp with a nice bit of tube warmth at a very good price. I bought this amp with no real expectations, I just wanted to hear what a $50 hybrid amp sounds like. Now after using it for about a week I haven't touched my Vali once, just saying.

Here's some specs,

Output power: ≥ 1100mW (32 ohm) 
Adapter Headphone Impedance: 18-600 ohm 
Total harmonic distortion: <0.005% Frequency Response: 20-30KHz 
Size: 111 * 69 * 32 mm (L * W * H) , (height 73mm when add tube) 
Net Weight: 185g

If anyone else has this amp or even another sub $100 hybrid let me know.


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## robert1325

Good find. Have you tried it with an efficient portable such as the px100-ii? Would the gain be too much?


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## Headphone4Life

I don't think the gain is a problem. My Sony Z7 are very efficient for what they are and they sound really good also but they're a dark headphone to begin with so they sound a little to warm with the Nobsound. I even tried my TDK BA200 with it and it sounded better than I thought it would. For a $50 amp I had no intention of using much (like I said I bought it just to see) it has surpassed all my expectations. I'm using right now with my 400i through my X3II and it sounds really good. I was going to sell it but not now, or at least not tell I get a new amp.


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## Dan-Fi

Hey I just received this little amp in the mail and I must say I was really impressed with the all-metal build. I'm listening to it right now with my Grado chromies, using my 4th gen iPod touch and Accudio with its SR325i setting. I must say it has improved in clarity compared to my existing cmoy with an LT1028 op amp. I think the soundstage has noticeably improved.
One thing though, when I turned on amp, there was a loud pop sound, even with the volume knob set to minimum. Did you get this as well, Headphone4Life? Otherwise I'm really enjoying this amp, especially given how cheap it is!


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## Headphone4Life

dan-fi said:


> Hey I just received this little amp in the mail and I must say I was really impressed with the all-metal build. I'm listening to it right now with my Grado chromies, using my 4th gen iPod touch and Accudio with its SR325i setting. I must say it has improved in clarity compared to my existing cmoy with an LT1028 op amp. I think the soundstage has noticeably improved.
> One thing though, when I turned on amp, there was a loud pop sound, even with the volume knob set to minimum. Did you get this as well, Headphone4Life? Otherwise I'm really enjoying this amp, especially given how cheap it is!


 
  
 Yeah, when you turn it on it does have a popping sound but I don't think its any problem with it.
  
 For the price I can't see anyone really complain about this little amp.  I'm shocked that it sounds better than my Vali with my HE-400i.  I don't like the way my Sony Z7 sounds with it though but I didn't buy it for them anyways.  Plenty of power to push most headphones no problem and really good SQ for what you pay for, anyone on a really tight budget should check this hybrid amp out.


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## Dan-Fi

Yes, I was on a tight budget and this was my first listening venture in tube-land, albeit in a hybrid sort of way. It certainly does have plenty of power, as I'm only using it at the 3-4 mark on the volume knob and that's loud enough for me.
  
 With regards to the popping sound, it was pretty loud on my SR325is and it got me worried, so what I'm doing now is powering the amp up without it being connected to the headphone, wait about 10-20secs, then connect up my Grados. I don't hear any popping noise when I connect it this way!
  
 Haven't caught the tube-rolling bug yet....but I feel it coming...!


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## Headphone4Life

dan-fi said:


> Yes, I was on a tight budget and this was my first listening venture in tube-land, albeit in a hybrid sort of way. It certainly does have plenty of power, as I'm only using it at the 3-4 mark on the volume knob and that's loud enough for me.
> 
> With regards to the popping sound, it was pretty loud on my SR325is and it got me worried, so what I'm doing now is powering the amp up without it being connected to the headphone, wait about 10-20secs, then connect up my Grados. I don't hear any popping noise when I connect it this way!
> 
> Haven't caught the tube-rolling bug yet....but I feel it coming...!




I do the same thing you do and connect my headphone after I turn the amp on. 

I've only had this and the Schiit Vali as far as tube amps go but I'm planning on getting a better hybrid down the line some time. As you probably know straight tube amps don't normally work well with planar's so that's why I'm just looking at hybrids. I'm thinking of maybe getting the new Vali 2 which you can tube roll with unlike the original Vali. There's a few good hybrids I'm looking at maybe buying, but to be honest I'm in no hurry because I truly like the Nobsound a lot.


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## DestrucSean

How well do you think the Nobsound would pair with my Sennheiser HD 700 headphones?


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## AzraelDarkangel

I'm buying a NuPrime uDSD to pair with my laptop and might buy the nobsound to pair with it for a fun comparison. I don't need the extra power for my AD1000X since it's very efficient and low impedance but at $50 plus extra tubes, it's not an issue to buy.


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## Grizmo

destrucsean said:


> How well do you think the Nobsound would pair with my Sennheiser HD 700 headphones?




I have one on its way so I can see how it pairs with cans that have similar charachteristics. On paper it seems it would be a decent option for the hd700 to properly powering them.


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## Dan-Fi

Well I just got myself an AKG K145/S for....AUD$5! I'm testing them out on the Nob and this little amp can easily drive these 200 ohm headphones! Listening to 80's music through my iPod touch connected via a Fiio LOD, I have the volume knob on the Nob at around 10 o'clock and it is just a tad too loud for me. Wow, these K145's are really nice....good detail and vocals are so crisp! I just need to find some new pads for them though as the existing ones have crumpled a bit....


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## HelgeW

I'm driving an AKG K702 with the Nobsound. I got the AKG some 3 weeks ago as I was curious about the "analytical" sound they are know for, and bought a Fiio E10K with them. The pair of them was not bad, but I was searching for a stand alone amp instead of the DAC/amp combi the Fiio is. And loving the sound of my Bradford tube amp driving my loudspeakers, I was watching in that direction.
 I have the Nobsound now since a week, and as the DAC is not yet ready, I'm feeding it by the Laptop, so the source is so lala. First (visual) impression is kind of strange: A cheap black profile housing bundled with a massive golden alloy front plate. But the best comes once you power it: The tubes are not just gliming in the soft orange I was used to, but are illuminated by some blue LED. All together - golden front plate, orange tubes, and blue LED - gives a really strange look.
 For the sound, I have to say, they add exactly the bit of smoothness to the AKG to bring them from "to analytical to be enjoyable" to "still great resolution, but soft enough to lean back and just listen". I can't compare to any more expansive amp, and as mentioned, the source is not exactly highend, but first impression is good.


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## trellus

I just ordered this on a whim... Been interested in trying a hybrid amp to see taste that tube flavor... Kind of hard to pass up for $50.


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## MachineGunz

Care to write your opinion once you get it?


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## Headphone4Life

I've been using my S.M.S.L sApIII amp a lot with my X5II but I hooked my Nobsound up to the X5II with my HE-400i and it sounds good. I get that little bit of warmth added to the mids along with a deeper soundstage and more full sound over all. I don't like the Nobsound with my Sony Z7 but with the Hifiman it sounds really nice. I can't think of an amp under $100 that would be better than this one. My sApIII was $65 3 years ago and I think it's equal to the NS-08E though with a different signature. Its more natural sounding with less warmth and that makes it pair great with my Z7 which already has a very warm signature.


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## edulov

There are several threads about this amp. Actually its very good, my old Senn HD430 (600 ohm) is a perfect match. Koss Pro 4AAT (250ohms) also sounded better. I even do not need more then 1/3 of the volume for Senn!
 But you should understand, that if yours came with stock Chinese 6JP valves (tubes) -* they are really bad.*

  
 I found and ordered other pairs of fine tubes quite cheap. Like day and night. Great improvement in highs, mids and especially lows and bass extension. Additionally I’ve got better soundstage. Not in width (left-right), compared with my main amp, but in depth (in front-behind).

 Later I shall order more valves to choose from and after selecting 2 best options I plan to play more, switching op amps (DIP8 package).
 Stock ones are good compared even with mid-class amps and very decent compared to HiFi amps.
 So all parts of "modding" is for people who do not believe much in recommendations and want to hear it personally. This cheap but good amp is a perfect option for this.

  
 BTW (Its not very strict thou) I found some “hardcore” hardware threads (in English and in Russian) which actually say that one pentode valve per channel sound much better then one twin-triode per channel. Cleaner, more natural, better soundstage and more power to drive hard cans.


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## DangerClose

Anyone know the power consumption on this or similar?  I don't think it's Class A.  I'd like to leave it on 24/7 but not if it uses a lot more power and creates a lot more heat than a typical little 10 watt amp.


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## edulov

PSU - 6V DC, 2A, so max consuption is 12W, but even for 600ohm 1/4 of volume is quite loud, so I doubt that you will use more then 5-7W
  
 The problem is not a consumption itself. Tubes/valves work fine several amount of time. Regular 6j9p works about 500 - 1000 hours.


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## DangerClose

Thanks.  Current prices on replacement stock tubes is as low as $1, but replacing them every month would still get annoying.


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## edulov

The "thin ice" here is not actually that valve will stop working. They degrade with time, may be unevenly. So the sound will change. In this amp valves are used for buffer, so your hearing will adopt to the changes in 24/7 sessions while the amplifier will keep working. I mean that you'll need to check the sound from time to time and replace valves upon your hearing criteria.
  
 BTW, I will check some relatively cheap valves later (in July) and on the opposite side - one very long life reference, "looking" at their sound.
 Very soon I plan to try 3 another op amps. Not the newest ones, but all of them received positive reviews and now they are really cheap, hoping that rolling cheaper tubes and op amps will provide stunning results. Fingers crossed.


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## edulov

I'v got a question on tube rolling, also I have some general comments and results of op amp rolling. Thus I'll post them here.
*Philosophy.*
 It does not matter how many times it was said or written, people still think that getting HQ is possible only from costly units. Gear is very important, especially for good headphones, especially high impedance ones (250 Ohm and above). But the result highly depends both on components quality and electrical/electronic design. Amplifier in mention has a simple, robust and smart design, so SQ mostly depend on components. Valve/tube is used as a buffer for inverse op amp connection where the buffer actually is a dynamic closed link which defines a big “cut” of SQ pie. But it also means that rolling op amp may improve or damage SQ. And – more rarely dynamic electrical connection between valve and op amp is unbiased giving sound artifacts and/or additional noises.
 The other side of the mirror is more complicated. SQ is flexible. Some elements like details, resolution, wide soundstage always count. Many other elements, especially quantity of bass and treble as a control over them are subjective. So I’ll mention only undeniable improvements.
  
*Rolling tubes.*
 Before anything else please understand that 6ж9п valve have many direct analogues and highly compatible ones also. Due to fabrication processes and materials they are not identical, so the devil hides in details. But first of all here is a list of all references, especially if you will look for them at eBay:
 6ж9п, 6j9p, 6g9p, 6zh9p, 6ж9п-Е, 6j9p-e, 6g9p-e, 6zh9p-e, 5A/170K, 6688, 6688A, CV3998, CV6189, E180F
Adding suffix letter usually means long life version of tube, also with refined specs.
Since I wanted to keep “playing” with this amp for some time, I tried some, definitely good options, but will continue testing after finding valves at reasonable prices.
  
At the moment I checked just 3 of them, but all - very good ones:
- General Electric 6688, US
 - RCA 6688A (made by Mullard)
 - Amperex JEP-6688, CША
  
 If you want studio-type sound you need GE. Detalization, resolution, separation of instruments, soundstage – exceptional. BUT! They do have bass extension w/o good punch and density. It does not mean that you will get problems with lows, since they are fully controlled. Just not too much. So this valve is not for bass heads.
 RCA and Amperex JEP are very similar. Just a little bit less of “open air” but much more prominent lows. Overall control is equal, punch and density. With one small detail – Amperex offers even bass density up to the lowest extension, while RCA offers less “body” at low-low bass. But once again, it will be important only for a hardcore bass head. Also RCA has lesser depth (not width) of soundstage, but you will need very good open cans to capture that. That’s why I am using Amperex JEP.
 A bit later I’ll try “normal” Amperex, comparing with JEP version and RCA’s once again.
  
*Op amp rolling.*
 Fooling with operational amplifiers is not so popular, since most amplifiers have them soldered.
  
 Our amplifier comes with DIP8 chips package and beds, so you can exchange them easily. But beware, you need electrical compatibility. That is why not all op amps in DIP8 package will fit (electrically). Also you must read corresponding threads since op amps are not equal. Many provide sound coloration. I prefer neutral sound without rolled-off higs and lows, so my list of candidates (considering prices and packaging) was quite short. I made it after harvesting forums in different languages. Take into account, that I am giving description how they sounded with my favorite tubes, but please believe me, my opinion virtually coincided with other people impressions from other amplifiers and sound cards.
  
 First of all, the factory installed NE5532 are old as mammoth ****, but in a well designed amplifier they offer very good balanced sound. Just a slight roll-off in treble and a little softness of treble too. Talking about preferences it makes NE5532 a perfect choice for many-many people, especially if they are sensitive to highs. It should be clear: a bright track in bright hp’s will sound bright, but not killing your ears.
  
 AD823ANZ is old also, but still very popular. Their sound character is not for my needs, but I can hear it w/o any hesitation. The sound reminds a magnetic tape, in a good sense. Sound is calm and clear, light in mids. Good bass control, some punch. Not much of body in lows, resembling magnetic tape sound even more. Slightly harsh treble, but only for high treble, so you’ll need special tracks and hp’s to hear that. The greatest negative for me (also reminding tape sound) is decent, but much narrower soundstage, compared to 5532. Only a hint of depth. It was noticeable even in fine closed cans, not only in a HiFi open ones.
  
 LME49720NA. Can’t say anything bad. As promised it offered incredible detalization, resolution and huge soundstage. Perfect control and balance everywhere. But this op amp has slightly different electric specs, so using it with my tubes caused little but clear “over” sound, like some derived noise, so I had to reject it. I was afraid it could happen, so I’ll try it with another tubes posting additional comments later. BTW – some people may call this sound a little bit clinical, which is not good for easy-going listening.
  
 LT1364CN8. It has a love-or-hate comments, showing that electric design affects its selection. In our case it is love. Studio, balanced sound w/o any imperfections. Great resolution and bass control. Top notch, honest treble. So some tracks could become too bright for you. Soundstage – wow! On a verge of placebo, comparing with LME. Absolutely natural sound of live instruments and vocals. A tad less detalization compared to LME, but captured that because I knew what might happen. You will need very good cans and quite specific tracks to hear such a difference. And the most important – no bias problems with my tubes.
  
 Beware! If you will choose "dark" op amp with bass-oriented tubes, the sound will float too far from being natural. Better find good bass heavy cans, keeping amp with balanced sound but extended lows. Combining op amp and tubes with rolled-off and "soft" treble also won't do any good.


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## edulov

P.S.
  
 Try to buy a batch of 3+ tubes, especially the used ones.
 1) As a backup
 2) If L/R sound different, 3 tubes give you 3 combinations to try
 3) Golden pins are better, indeed, but for much higher frequences (MHz). So there is no need to pay extra for the same reference. Magic happens inside the valve.
 4) When amp is ON, moving the box and touching tubes will couse "ringing" sound. A cuple of seconds is fine. But if "ringing" is long, or worse - permanent, try to check if the tubes were firmly installed first. If installation was correct - locate the ringing tube and replace it.


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## DavidK35

Could not resist, ordered one today, for desktop system. Plus some US NOS 6688A tubes.


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## edulov

Simple suggestions:
 1) Compare the sound of the stock tubes against another amp, the good one. And only afterwards try another tubes.
 2) In case of Panasonic RP-HTF600 & AKG 271 cans you will hear improvements, but not so much for lows due to their FRC's. In my setup AKG 271's lows got some body (not a placebo) and much better bass control, but it was happening with all my cans.
  
 I'll apreciate if you can share the results comparing the sound of NS-08E with Little Bear.
  
 Another comment, comparing my Topping TP32EX with Fiio E10K(line output)+Nobsound NE-08E. There are small differences, I can describe them, but the biggest difference was in the perception of the sound space created by headphones.
  
 For Nobsound I've found myself inside bigger hall, and more surprisingly the sound was more clear, like the walls were covered by marmol providing more reflextions. BTW, the use of GE tubes gave sensation of the huge hall, (Not the size of the soundstage, but how do you interpret the imaginary sound space).
  
 For Topping I feeled that walls were draped by thick cloth. Also a big-big hall, just smaller then others.
  
 Actually it is a nice combination, since some music styles sound more lively and natural with Topping, others - in Nobsound.
  
 So for now I'd love to get an indication which hybrid/tube amp (valve+op amp rolled may be) can offer the effect of big!!! hall with wooden walls. Reasonably priced of cause.
  
 Since I've heard music in different ambients, I am quite sure about my impressions.
  
 Cheers!


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## edulov

Finally made a comparision between
 1) JEP Amperex 6688 - my favourite
 2) Amperex 6688A - the goal of comparision, NewOldStock, US made
 3) RCA 6688A by Mullard
  
 The main idea was to compare how "special" Amperex go against regular ones and another fine valve pair.
 For good or for bad the summary of the sound signatures and dufferences is short and simple.
  
 1) most control over bass; dense, punchy lows everywhere; extended lows; exact reproduction in all FR range
 2) less control over bass, dense (less at low bass), punchy lows, but more boomy then 1); details, resolution - they have it, but overall sound is "smoother"
 3) slightly less control over bass, dense (less at low bass), punchy lows; details, resolution - they have it, but overall sound is "smoother"
  
 For me:
 1) goes ranked as the best between tubes rolled by me
 3) Have 2nd place, good for relaxed music listening, not getting heavy in bassy tracks
 2) Ranked 3rd, good for relaxed listening to music, more for bassheads
  
 P.S. for "experts" who might doubt Fiio 10K capabilities. DAC part of the device is very good, so presence of linear output is a gift of gods. You  can use it as DAC/AMP outside home with normal hp's and connect better AMP to it at home for better cans.


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## DangerClose

Not only is there not a 1/4" jack on this, but the 1/8" jack is recessed, so typical 1/4" to 1/8" headphone adapters won't fit.  Bad news for my K701.  
 A couple of my 1/8" headphones barely fit too.  An extension adapter cable works, but I need to try a shorter one since my 10-foot one hurts the sound quality. 
  
 It should go without saying that an electronic device should be in a secure spot.  This one lets you know when it's not by giving a pinnnggg sound when bumped. 
	

	
	
		
		

		
			




  
 I think the headphone output ohms is pretty high.  Without a gain switch, this isn't an ideal amp to use with easy-to-drive headphones anyway.
  
 Gets kind of hot.  I'm thinking about cutting a few air vents in the top.
  
 It softens the sound.  I had no plans on tube rolling with this, but you say the stock tubes are really bad.
  
 I'm trying to figure out if the tubes can be bypassed.  It looks like they can, but I'm not a circuit board whiz.


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## edulov

1. Bad design of the front panel (with deep holes for connector cables ) complicates connections, but there are different long tip jacks just as the fine thin cables. I have both options.
 2. Amp have so much power that I don't need any gain switch, volume knob is enough.
 3. Stock tubes are so bad, that any other will be better. I saw a lot of them quite-quite cheap, even from fine makers. Beware of the differences in bass and bass extension.
 4. Electric scheme of this amp REQUIRES some element as a buffer in a "closed-loop" connection for inverse op amp use. This buffer is made on the basis of the other solid op amp (like the finest soundcards and other amplifiers due to size restrictions) or using vacuum valve (triode or pentode). Better say that without it things just won't work for this electric design.
  
 BTW, tube rolling is one of the funniest parts, while using a vacuum or hybrid amps.


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## DangerClose

edulov said:


> 2. Amp have so much power that I don't need any gain switch, volume knob is enough.
> 
> 4. Electric scheme of this amp REQUIRES some element as a buffer in a "closed-loop" connection for inverse op amp use. This buffer is made on the basis of the other solid op amp (like the finest soundcards and other amplifiers due to size restrictions) or using vacuum valve (triode or pentode). Better say that without it things just won't work for this electric design.


 
  
 It could use a switch to lower the power so the volume knob is more useful and in its best zone.
  
 I know the tubes are required as it is, but you're saying the tubes can't be bypassed with a soldered wire somehow, at all.  There's pins on the tubes that aren't connected to anything.  Some circuit guys chatted a little about it and said it should be easy to bypass the tubes, but they only looked at it casually.
  
 I like it overall as-is, I'm just wondering how it might sound without the tubes, and also thinking ahead to if I use it a lot and start wearing out tubes constantly. lol.


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## edulov

Tubes/Valves (or op amps in similar designs) are functional in this electric scheme, so w/o it in the best case scenario you won't get enough power to drive high impedance headphones. For me it is one is the most important specs of this amplifier, equally important to the possibility to roll both tubes and op amps.
  
 Since you ignore rolling and don't need so much power - why did you bought this amp in the first place?


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## DangerClose

edulov said:


> Since you ignore rolling and don't need so much power - why did you bought this amp in the first place?


 
  
 Who said I don't need so much power. I just don't need so much power all the time.


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## edulov

To avoid technical discussions WHY you should not use selectable gain w/o real necessity, remember one of the basic rules for designing electric/electronic components:
  
 More components, more wires - more distortions.


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## DangerClose

edulov said:


> To avoid technical discussions WHY you should not use selectable gain w/o real necessity, remember one of the basic rules for designing electric/electronic components:
> 
> More components, more wires - more distortions.


 
  
 People should buy the Magni 1 and not the Magni 2 since the 2 has a gain switch and so more distortion?  
  
 I don't expect lots of features on this amp for the price.  They'd just be nice is all.  I can like it while also pointing out its shortcomings.


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## edulov

Ok. To avoid discussions in electronics, a valid answer: Magni (and some others) were designed electrically with a gain feature right from the beginning. Calculated and tuned in respective sections. NE08 was not designed with it in mind and SQ will suffer.


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## DavidK35

Well, I have had this amp a couple of weeks now & before I talk about it I just want to clear up a few things first.
  
 1) This amp does not run hot, warm yes but not hot. You can put your fingers on it & leave them there all day if you wish.
     It does not need any extra heatsinking, or extra holes, not to mention the 2 big holes already in the top for the tubes.
  
 2) I don't have any problem with the adaptors fitting. In fact the recesses IMO have been designed to perfectly accomodate said adaptors.
     The recesses are large enough diameter & shallow enough NOT to interfere, and add to the overall aesthetics.
  
     Here is a link to an adaptor that is not 10ft long. I use this for my fostex phones that only have 1/4" jacks. It will set you back a
     whopping $3
  
     http://www.ebay.com/itm/252322042871?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
  
  3) Bypassing the tubes is the silliest thing I have heard for a "tube" amp.
  
 This amp is well constructed & looks great, probably the greatest hifi bargain out there for $44 inc shipping.
  
 First I threw out the junk chinese tubes & replaced with 2 RCA NOS 6688A tubes (a whopping $20 total) & just ran it for a few days before any listening. I think the tube choice is part of the magic too. These miniatures seem way under appreciated in the audiophile world.
  
 Sounds way way above it's price point. Not the last word in sound quality(maybe) but extremely good (about 90%+ towards nirvana, LOL).
  
 Warm yes, but clear & detailed with the AKG241's. No detectable distortion & in fact best I have heard these phones & partner extremely well with this amp. Seem to get a little bit extra bass & much less sibilance with these cans also.
  
 The tech spec's are impressive too, 1.1W @ 32 ohms, 0.005THD 110SNR
  
 Can easily live with this amp, for a desktop system you really do not have to look any further.


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## DangerClose

davidk35 said:


> Well, I have had this amp a couple of weeks now & before I talk about it I just want to clear up a few things first.
> 
> 1) This amp does not run hot, warm yes but not hot. You can put your fingers on it & leave them there all day if you wish.
> It does not need any extra heatsinking, or extra holes, not to mention the 2 big holes already in the top for the tubes.
> ...


 
  
 I already said I like the amp.
  
 I said it gets "kind of hot." Which it does.  Electronics usually like to be cool, so while saying it doesn't "need" more venting may be accurate, more venting could potentially prolong its life.  Not everyone uses such things in a well-ventilated, 70-degree A/C'd space, either.  Do you think more venting would possibly hurt more than possibly help?
  
 That adapter may only be a "whopping" $3, but it also adds an extra cable, and that can affect the sound.  I got a new DAC yesterday and tried it with this and was immediately disappointed at it sounding dull.  I then tried different cables and got different sounds. So I prefer to avoid adding more unknown cheap cables into the equation with an adapter.  I was going to post about that yesterday but figured someone would want to fight about cables not mattering or about how this amp always sounds perfect.
  
 You say bypassing the tubes would be silly because it's a tube amp. What's silly is not considering someone may want the power for the price while not necessarily caring whether it has tubes or not, and not wanting to possibly have to replace two tubes every 500-1000 hours. Mine will probably be left on 100+ hours a week. If using two of the better recommended tubes, every year the tubes cost the same price as the amp did, or more.  After two years of use, the cost usage of the amp would be around $150 or more and continue to rise. If so, there's other amps to consider in the $150+ range that someone may or may not prefer. 
  
 I have multiple 1/4-1/8 adapters. They don't fit.  
 I put my Fostex 3.5mm cable in there.  It fits, but it's small and needs to be tweezered a bit when trying to remove it.  
 You say the recesses have been perfectly designed for said adapters.  Well, my generic adapters don't fit, and my Takstar adapters don't fit, and my Sennheiser adapters don't fit, so I don't think the recess is perfectly designed.
  
 These are generally minor shortcomings for the price, but covering up potential problems of this amp doesn't do potential buyers any favors.


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## DavidK35

_I said it gets "kind of hot." Which it does_
  
 I stand by my original statement, it gets warm not hot.
  
_ Electronics usually like to be cool, so while saying it doesn't "need" more venting may be accurate, more venting could potentially prolong its life.  Not everyone uses such things in a well-ventilated, 70-degree A/C'd space, either._
  
 As stated, heat is not an issue so it is completely irrelevent, but hey whatever floats your boat.
  
_That adapter may only be a "whopping" $3, but it also adds an extra cable, and that can affect the sound_
  
  
 Here is the solution for you:
  
 https://www.amazon.com/BesYee-2-Pack-conductor-female-adapter/dp/B0177DCOIS/ref=sr_1_5?s=audio-video-accessories&ie=UTF8&qid=1468435639&sr=1-5&keywords=1+8+female+to+1+8+male+adapter
  
 And a picture if the link doesn't work
  

  
  
 Slim, slim, slim, gold plated, lookee no cables, what a bargain only $8 for two.
  
_You say bypassing the tubes would be silly because it's a tube amp. What's silly is not considering someone may want the power for the price while not necessarily caring whether it has tubes or not_
  
 Your right it's not silly, it's downright ridiculous
  
_not wanting to possibly have to replace two tubes every 500-1000 hours. Mine will probably be left on 100+ hours a week. If using two of the better recommended tubes, every year the tubes cost the same price as the amp did, or more.  After two years of use, the cost usage of the amp would be around $150 or more and continue to rise. If so, there's other amps to consider in the $150+ range that someone may or may not prefer._
  
 First of all most tubes (excluding the chinese junk & maybe the modern tubes ( I don't know because I never use them)), including NOS miniatures are usually rated for 5000hours & some @ 10000hours (especially military).
 So 5000/100 = 50 weeks, roughly a year say. Worst case I think you would be spending $20 per year per set. Big bucks.
  
 Incidentally my main power amp has tubes in the preamp & SS in the output just like this one. In this application I dont think It is
 working that hard. In the last 7 years or more I have only had to replace 1 tube. I do not expect to be changing tubes like you are suggesting & are just making a mountain out of a molehill.
  
_I have multiple 1/4-1/8 adapters. They don't fit.  _
_I put my Fostex 3.5mm cable in there.  It fits, but it's small and needs to be tweezered a bit when trying to remove it._
  
 See above, not an issue
  
_You say the recesses have been perfectly designed for said adapters.  Well, my generic adapters don't fit, and my Takstar adapters don't fit, and my Sennheiser adapters don't fit, so I don't think the recess is perfectly designed._
  
 OK, I will rephrase that "it's been nicely designed to fit most peoples headphone jacks and/or adapters, for those that do have problems, see above"
 You know it's interesting, if you go to Amazon there are 68 reviews of this amp, mostly good, but if you look at the complaints not 1 single person has any issues with heat or adaptors, weird uhh.
  
_These are generally minor shortcomings for the price, but covering up potential problems of this amp doesn't do potential buyers any favors_
  
  
 That's a serious accusation there pal. There is no cover up going on, once again you are being overly dramatic. My assessment is as I see it. Like I say I believe this is the greatest bargain in desktop amps today bar none and I cannot find any issues at all in this equipment  which is a very rare thing. I am very picky & have tried at least 4 head amps before this. Right now I do not see any need to upgrade in the future. The only unknown is long term reliabilty, but only time will tell.


----------



## DangerClose

What's the difference between "warm" and "kind of hot?"  
  
 Mine's in an 86-degree room right now.  I put my hands on an LCD monitor.  It's warm.  I put my hands on the amp.  It's on but not being used, and it's kind of hot. 
  
 You posted another link to an adapter, along with what looks to be some aggressive/snide comments.  You still seem to want to brush aside the actual point that the recessed plugs are not typical and could cause a problem with some people's equipment.  Takstar doesn't fit.  Sennheiser doesn't fit.  That shouldn't be a dealbreaker, but it's possible for some people.  I already said I consider it a minor problem especially for the price, but it still is what it is and trying to brush aside criticisms of the amp doesn't do people any favors.  If so, may as well rename this to the "Nobsound is perfect, reply if you agree" thread.
  
 And yet again you insert aggressive/snide comments about the price of tubes.  Even $20 a year, 2-3 years of use makes this the same price as a Magni or other things, and more expensive every day after that.  Some people may think such considerations are unimportant, but other people may not, and they may decide to get something different after factoring in cost of use.
  


davidk35 said:


> You know it's interesting, if you go to Amazon there are 68 reviews of this amp, mostly good, but if you look at the complaints not 1 single person has any issues with heat or adaptors, weird uhh.


 
  
 How many of those people are using headphones with 1/4" ends?  Probably not many.
  


davidk35 said:


> _These are generally minor shortcomings for the price, but covering up potential problems of this amp doesn't do potential buyers any favors_
> 
> 
> That's a serious accusation there pal. There is no cover up going on, once again you are being overly dramatic. My assessment is as I see it. Like I say I believe this is the greatest bargain in desktop amps today bar none and I cannot find any issues at all in this equipment  which is a very rare thing. I am very picky & have tried at least 4 head amps before this. Right now I do not see any need to upgrade in the future. The only unknown is long term reliabilty, but only time will tell.


 
  
 You're the one being overly dramatic, taking minor criticisms of this amp that would-be buyers might like to be aware of and acting like they are a personal affront to you. And you're being aggressive and snide about it, pal.  
  
 Takstar and Sennheiser adapters don't work?  Who cares!
 Stock tubes suck, need to be replaced with more expensive ones, and depending on hours of use this "cheap" amp may cost more than a Magni?  Who cares!
 Wondering if you can take this bargain amp that only uses the tubes for a buffer anyway and eliminate the tubes to make it a solid-state bargain amp that never needs the tubes replaced? That's silly and ridiculous!  Just buy a Magni for 2x+ as much instead!
  
 You say the only unknown is long term reliability.  Electronics tend to have a longer life if they run cooler, but fortunately for this electronic device I'm told heat is completely irrelevant.
  
 We both like the amp.  I'm trying to discuss it more than just saying it's great.


----------



## antdroid

I just picked this hybrid up very impulsively. I was looking for something to get me over the hump for Amazon same-day delivery and stumbled upon it and then looked up a really random review from Sound & Vision magazine that liked it and just jumped on it also based on the amazon reviews and I'm pretty happy with it. What a steal! 
  
 It's solidly made and looks unique enough mostly because of the compact size and odd color choices. I really had doubts on how much signal noise or distortion it would make but this actually sounds great. The warm signature it brings is quite enjoyable. I really liked it paired with my HTC 10. I was looking for a small little amp to help it with some planar magnetic headphones (Fostex T50RP and soon to be coming Audeze Sines) and this really pairs well with the HTC 10 DAC sound which is a little bit more V/U-shaped than I like raising some of the mids back to enjoyable levels and actually made details come out a little more and open up the soundstage a bit wider.
  
 I also paired these with my MSI Laptop which uses an ESS Sabre Hifi DAC/Amp which is pretty capable of pushing most headphones and I didn't really like the results as much. It made the mids and bass a bit too boomier than I'd like with a little loss of detail. That said, the discrete dac/amp sound really good on its own so I didnt need to mess with a good thing.
  
 To the previous comments, it does get a tad warm but I would not call it "hot" by any means. You can touch it and keep touching the amp surface (not the tubes!) and be fine. I used a variety of different headphones (various IEMs, buds, and headphones with different cables) and I didn't experience any issues plugging them into the jacks. I could see how some cables may have trouble but I've switched out all my 3.5mm detachable cables to ones that work with recessed ports because they need to be anyway to work with my headphones.


----------



## DangerClose

antdroid said:


> To the previous comments, it does get a tad warm but I would not call it "hot" by any means. You can touch it and keep touching the amp surface (not the tubes!) and be fine. I used a variety of different headphones (various IEMs, buds, and headphones with different cables) and I didn't experience any issues plugging them into the jacks. I could see how some cables may have trouble but I've switched out all my 3.5mm detachable cables to ones that work with recessed ports because they need to be anyway to work with my headphones.


 
  
 Some of my larger 3.5mm might be a close fit, but they fit.  It's adapters that can be a problem. It's a minor thing, but it's a thing.
  
 If this isn't considered kind of hot, then the Schiit Magni is like in a freezer.  It's not even close to the temperature my NS08 gets.  Does such a temperature difference matter?  Is the NS08 designed to operate fine for decades at the higher temp?  Does my particular NS08 run hotter than yours for some strange reason?  Who knows.


----------



## DavidK35

Thank you for your common sense review of this amp. I concur with what you say.
  
 On a different general note, does anyone have any expertise on power supplies.
 I am currently using a regulated switching power supply but I have seen reference
 to "linear" regulated power supplies. Anyone know if there would be any benefit
 in using this kind of power supply?


----------



## edulov

Several thoughts could be totalled (not in any specific order).
 1. From the valves I tested the stock ones were the most hot ones. All other I was replacing by bare hand immediately after switching off. And I am not a Lava man to deal with really hot items.
 2. Stock valves sound too warm (but it could be up to someone taste) and muddy. The better cans you have, better heard. So *any* other pair of tubes is better. But beware, some may give too lean lows (up to taste, but gives strange feeling at bass heavy tracks).
 3. Even a stock op amps are good, but also could be rolled.
 4. Power supplies coming with amp could be different, they are acceptable if you were lucky, but try another one if you hear some noises, especially periodic ones. For this type of devices it could mean heavy wear of valves of PSU problems, but periodic rumble is not coming from tubes.


----------



## antdroid

edulov said:


> Several thoughts could be totalled (not in any specific order).
> 1. From the valves I tested the stock ones were the most hot ones. All other I was replacing by bare hand immediately after switching off. And I am not a Lava man to deal with really hot items.
> 2. Stock valves sound too warm (but it could be up to someone taste) and muddy. The better cans you have, better heard. So *any* other pair of tubes is better. But beware, some may give too lean lows (up to taste, but gives strange feeling at bass heavy tracks).
> 3. Even a stock op amps are good, but also could be rolled.
> 4. Power supplies coming with amp could be different, they are acceptable if you were lucky, but try another one if you hear some noises, especially periodic ones. For this type of devices it could mean heavy wear of valves of PSU problems, but periodic rumble is not coming from tubes.


 
 I prefer tubes that would give me a slight warmth but mostly neutral signature but widening the stage a bit to use with my HTC10 (uses the new Snapdragon Acqstic DAC). Do you have any recommendations?


----------



## edulov

To avoid thinking about quality but being possible to find at a good price - look for Mullard or Mullard made. BTW, I was lucky finding valves at eBay, even from garage sales. And cheaper than special stores. But if you have one within an hour car ride - better get them with some guarantee.


----------



## Dan-Fi

@edulov, how stable is the LT1364 in this amp? Has there been any noticeable deterioration in sound over time? I had a pair ordered a while ago and tried each out on my cmoy, but I think I fried them due to circuit incompatibility, which, not being an electronics expert, I didn't know at the time. I'm currently listening to Blondie on my NS-08 using Dario E180F's and OPA2107's with my Grado SR325is and am enjoying the sound, but I'm intrigued about the soundstage the LT1364 has to offer and am considering buying a pair of these again...


----------



## edulov

Sorry for the delay. LT1364 is a perfect match with different tubes, just don't mess with a key leg. LT offers refined sound compared to many others with both bass and treble ext., very good control. According to specs LT has slightly lower noises at high treble, but 2107 offer slightly better gain. The thing is that I can't use more then 1/3 of the amp's volume even for 600 Ohm headphones, not even talking about standard 16-32 ones. So this becomes irrelevant.
  
 Some mentioned that OPA's provide darker sound, so I exluded them from my consideration, since if I want dark sound, I have headphones for that.
  
 Testing different op ams and valves in this amp I got a clear understanding that most effect at soundstage is caused by tube rolling, swithing op amps you can improve it only slightly, mostly in terms of positioning of instruments.


----------



## Dan-Fi

Thanks very much for the response and good to know that LT1364 works well in this amp. I have used LT1028 and LT1057 op amps in my cmoy and agree that they sound more refined than the BB's I've tried, such as 2107 and 2111. As you said, OPAs do have a darker (but to me only slightly) sound than the LTs, which works for my SR325is and even my AKG K145/s, the latter of which I think is the harsher sounding of the two in treble. I'm only using 2107 over the stock op amp as that is the only one in my stock where I have a pair of that works 
  
 Current problem I'm having is with the power supply that came with the amp, or possibly with the power socket, as I'm hearing a background hiss every now and then. But if I wiggle the power jack, the hiss does disappear, as long as I don't move the cable again! I've ordered another 6VDC/2A power plug to see if a loose jack is the cause of the problem.


----------



## edulov

Faced noisy PSU problem, but in you case, I think you have to clean up contacts in the wall outlet first. Most people don't pay attention that some metal alloy is not so resistant to oxidation or become covered with thick ash after small electric sparks inside if there is a bad contact with plug. But be careful, cut off the main switch first.


----------



## Subhakar

edulov said:


>


 
  
  1. I ordered Nobsound 6J9 from this link: https://www.aliexpress.com/item/Music-Hall-6J9-Vacuum-Tube-Integrated-Amplifier-Mini-Audio-HiFi-Stereo-Headphone-amp-DIY-Free-Shipping/32443111524.html?spm=2114.13010608.0.0.RQn3jj
 Is it fully assembled one or a tedious DIY?
  
 2. The stock opamp this one comes with is half decent at least? 
  
 3.  Which tubes do you suggest for replacing the stock ones with?! I can spend a maximum of $10 on each. I am using them with beyerdynamic* DT 990 (600ohm)*. I like neutral and analytical studio-like signature with a little bit of bass and a great soundstage LxWxH that is possible.
  
 Thanks.


----------



## Brian Coffey

subhakar said:


> 1. I ordered Nobsound 6J9 from this link: https://www.aliexpress.com/item/Music-Hall-6J9-Vacuum-Tube-Integrated-Amplifier-Mini-Audio-HiFi-Stereo-Headphone-amp-DIY-Free-Shipping/32443111524.html?spm=2114.13010608.0.0.RQn3jj
> Is it fully assembled one or a tedious DIY?
> 
> 2. The stock opamp this one comes with is half decent at least?
> ...



I purchased mine from the same store and have been very impressed with it so far. I replaced the original tubes which I didn't think sounded all that bad with NOS Amprex 6688a. There was a fair amount of improvement in range and tone. The amp itself is fully assembled except for inserting the tubes.


----------



## Subhakar

brian coffey said:


> I purchased mine from the same store and have been very impressed with it so far. I replaced the original tubes which I didn't think sounded all that bad with NOS Amprex 6688a. There was a fair amount of improvement in range and tone. The amp itself is fully assembled except for inserting the tubes.




Thanks. Any particular site I can buy NOS Amprex 6688a from? Preferably in India/Asia? Can't find one locally.


----------



## Brian Coffey

subhakar said:


> Thanks. Any particular site I can buy NOS Amprex 6688a from? Preferably in India/Asia? Can't find one locally.




Sorry I got mine from Ebay here in the US.


----------



## Prohobo

I just ordered one of these little amps for my HE-400s to hook up to my computer at work.
  
 This will be my first TUBE amp and I also ordered a set of these tubes, any thoughts?
  
 https://www.amazon.com/gp/product/B0002M72JS/
  
Electro-Harmonix 12AX7EH Preamp Vacuum Tube  
  
 Of course I am a newbie - so I welcome suggestions.


----------



## Headphone4Life

They should be fine. Lets us know how it sounds with the 400s. I thought this little amp sounded better with my dynamic headphones more than with my HE-400i. Even though I don't use this amp anymore I hooked up my Focal Elear and it didn't sound half bad.


----------



## edulov

Sorry, but these are incompatible.
 You need one of those:
5A/170K
6j9p (6ж9п)
6688
CV3998
CV6189
E180F
EF861
EF180
  
If you order any valves untested, get 3 and select by ear a pair which provides balanced sound for L/R


----------



## Prohobo

jajajaja
  
 So there is a reason they call this amp NOBsound - I guess I am the NOB?!?!?!
  
  
 I was told these tubes:
  
E180F, EF861, 6688, 12AX7


----------



## edulov

Valve compatibility is not a secret. Even on eBay, you will find correct cross-references trying to search for 6j9p (6g9p), both are the transliteration of a Cyrillic letter "Ж". I know about one another 100% electrically compatible lamp, but dunno how it sounds, still planning to try it on. Also, there are some more from the same "family" 6ж, partially compatible.


----------



## cam94z28

Just got this little amp, and I'm already amazed!
  
 I've always had a "problem" with my ears, where either mine are more sensitive than everyone else, or they are about 10x more sensitive to sibilance, and "beaming" mids than most people. To the point that there is a physical reaction in my ears (mostly the left) to sibilant peaks. This amp might be the holy grail, in my case.
 I have been listening to my most sibilance prone headphones, and some known-sibilant songs. It's like this amp picks the sibilant ranges ONLY and smooths them over, without having much of an effect on the rest of the range. Is this the tube sound that everyone is raving about? If so, I'm a believer! I have a Schiit Vali (series 1), and it doesn't smooth the sound over like this. Maybe part of it is that it seems to have A LOT more headroom than the Schiit, so it still sounds good at lower volume. No noise, or background hiss so far, either. Here's hoping these tubes don't "break-in" to a bright nightmare.
  
 So, if you're hyper-sensitive like I am, you might want to drop the $45 and experiment. As for tube rolling, are there any compatible ones available on amazon? I couldn't find any, and I don't like ordering from "hole-in-the-wall" (bob's tubes) sites. Can't use eBay (don't ask).


----------



## edulov

If you are using stock tubes just bear that they provide horrible highs and overall mushy sound. Better valves are required, but what you call smoothing still be there because tube based amps are richer in harmonics, especially if they use pentodes like 6j9p. I dealt with sibilance sensitive cans and sibilant tracks and can say that with this amp the worst combinations are "on the edge" w/o damaging the sound or hurting ears.
 Talking about tube rolling I ordered mine from eBay - no problems. Amazon's sellers don't have compatible tubes.
  
 I am not a seller, but eBay is not so risky, there exist US based top rated sellers. Do not forget that you need a pair of equal tubes. Just look at least here http://www.ebay.com/itm/Mullard-6688-E180F-Vacuum-Tube-Gold-Pins-NOS-NIB-Tested-Strong-More-Available-/172401588219?hash=item2823ef77fb:g:aPMAAOSw9IpX0v9I or http://www.ebay.com/itm/Amperex-PQ-6688-E189F-Vacuum-Tube-NOS-NIB-Tested-Strong-More-Available-/172336256494?hash=item28200a95ee:g:H3kAAOSwFe5X0vOP


----------



## sup27606

Stumbled upon this little amp. I have a question. I saw a new amp has come out Nobsound NS-01E with similar power output as the NS-08E, but with only one tube. https://www.amazon.com/dp/B01I19SBPM/ref=psdc_537344_t2_B014FASL1A?th=1
  
 Has anyone compared this one with the NS-08E, and if I am to buy one, which one should I go for, NS-08E or the newer NS-01E?
  
 Thanks.


----------



## cam94z28

edulov said:


> If you are using stock tubes just bear that they provide horrible highs and overall mushy sound. Better valves are required, but what you call smoothing still be there because tube based amps are richer in harmonics, especially if they use pentodes like 6j9p. I dealt with sibilance sensitive cans and sibilant tracks and can say that with this amp the worst combinations are "on the edge" w/o damaging the sound or hurting ears.
> Talking about tube rolling I ordered mine from eBay - no problems. Amazon's sellers don't have compatible tubes.
> 
> I am not a seller, but eBay is not so risky, there exist US based top rated sellers. Do not forget that you need a pair of equal tubes. Just look at least here http://www.ebay.com/itm/Mullard-6688-E180F-Vacuum-Tube-Gold-Pins-NOS-NIB-Tested-Strong-More-Available-/172401588219?hash=item2823ef77fb:g:aPMAAOSw9IpX0v9I or http://www.ebay.com/itm/Amperex-PQ-6688-E189F-Vacuum-Tube-NOS-NIB-Tested-Strong-More-Available-/172336256494?hash=item28200a95ee:g:H3kAAOSwFe5X0vOP


 

 I actually found this place near me. They supposedly have 3.5 million tubes in stock, over 2000 different types, in a 7500sq. ft. warehouse. I emailed them, and they have Amperex 6688 JAN, for $7 each. I will be picking up a few on Friday.
  
 http://www.thetubecenter.com/contact_thetubecenter.html


----------



## edulov

cam94z28 said:


> I actually found this place near me. They supposedly have 3.5 million tubes in stock, over 2000 different types, in a 7500sq. ft. warehouse. I emailed them, and they have Amperex 6688 JAN, for $7 each. I will be picking up a few on Friday.
> 
> http://www.thetubecenter.com/contact_thetubecenter.html


 
 Good deal, reasonable price. BTW, 1) do not apply much force to the sides while "extracting" tubes. Just pull them up, slightly rocking back and forth 2) your new tubes will be smaller in size, its fine, do not worry


----------



## edulov

sup27606 said:


> Stumbled upon this little amp. I have a question. I saw a new amp has come out Nobsound NS-01E with similar power output as the NS-08E, but with only one tube. https://www.amazon.com/dp/B01I19SBPM/ref=psdc_537344_t2_B014FASL1A?th=1
> 
> Has anyone compared this one with the NS-08E, and if I am to buy one, which one should I go for, NS-08E or the newer NS-01E?
> 
> Thanks.


 

 Right about this design - no info. But what worries me most is
 1) A couple of posts definitely are promotional, not actual reviews
 2) NOBODY, even manufacturer tells the valve reference. Never liked such behavior. 
 3) Valve here must be one of the dual triodes, but which one and how many options for tube rolling will provide this reference? Since one certain tube spec is responsible for resolution, details and attack you can make a quite good prediction about sound just looking at the tube ref and manufacturer specs.
 4) No board images found, so no info about electric scheme and parts. Due to the small size of the amp, the op amps have to be in small modern packaging soldered to the board (so no op amp rolling...). Since the overall sound quality heavily depends on them too, just knowing their reference might greatly help, but...
 5) Just triode provide only even harmonics. Their presence is required by purists from music, but the absence or too strangled 1st and 3rd harmonics make the sound way to analytical and lifeless.
  
 Ok. If you will order NS-01E, tell us about tube and make a couple of good HiRes photos of the insides.


----------



## sup27606

edulov said:


> Right about this design - no info. But what worries me most is
> 1) A couple of posts definitely are promotional, not actual reviews
> 2) NOBODY, even manufacturer tells the valve reference. Never liked such behavior.
> 3) Valve here must be one of the dual triodes, but which one and how many options for tube rolling will provide this reference? Since one certain tube spec is responsible for resolution, details and attack you can make a quite good prediction about sound just looking at the tube ref and manufacturer specs.
> ...


 

 I agree with all of your points above, and hence went for the more established NS-08E. So far I haven't regretted. Using it with the Audeze Sine. Now, compared to this one, the Cayin C5 amp sounds thin and emaciated. The sound from the NS-8E has a heft and body to it that is unmistakable. The drums reverberate and the vocals shine. Paul Simon's Dazzling Blue comes alive, and Diana Krall is just seductive now. Thanks for your response to my question.


----------



## sup27606

Whats the difference between Amperex 6688a and 6688?
 Thanks.


----------



## edulov

sup27606 said:


> Whats the difference between Amperex 6688a and 6688?
> Thanks.


 
 According to the US electron tube military handbook letter "A" at the end of designation refers to the relialable version which means greater stability of electric parameters and potentially is better in everything. Other frequent letters are "JAN" used to designate military grade valves, both offering greater reliability, and longevity.
  
 If you will look for Soviet (Russian) made valves, some references have the final letter -E (long life) or -ДР (-DR for long life&gold plated pins, usually military grade).
  
 BTW, 6Ж9П-Е (6J9P-E) does exist! Can be found on eBay from many eastern Europe sellers. Quite cheap.


----------



## cam94z28

Just wanted to mention a weird "feature" of this amp with stock tubes. On lower impedance/higher sensitivity headphones it seems to remove bass, but on less sensitive, slightly higher impedance headphones, like my ancient Philips SHP895's, it actually adds bass, compared to a SS amp. Maybe it has a higher output impedance?
  
 I haven't picked up those 6688's I mentioned yet, but my dad found a huge box (rubbermaid tote) of old NOS tubes in the attic. Crossing my fingers there are some 6688's in there, once i get my hands on it.


----------



## Nrocket

Any Master and Dynamic MH40 use with the Nobsound? I'm thinking of getting it.


----------



## Audiophilic10

Maybe this has been asked already: Any amp from this brand at similar price point without the tubes?
 I saw this video about reverse-engineering it: https://www.youtube.com/watch?v=coSt5HWRvv4
 Sorry to introduce controversy here, but if you jump to the end they say that basically the tubes are just forced into the design for the sake of showing tubes and without them the amp would be even cheaper and function better...


----------



## sup27606

audiophilic10 said:


> Maybe this has been asked already: Any amp from this brand at similar price point without the tubes?
> I saw this video about reverse-engineering it: https://www.youtube.com/watch?v=coSt5HWRvv4
> Sorry to introduce controversy here, but if you jump to the end they say that basically the tubes are just forced into the design for the sake of showing tubes and without them the amp would be even cheaper and function better...




They didn't say the tubes are there for show. The tubes are not used for real amplification, but used as buffer which color the sound possibly by introducing some distortion. The tubes have an effect on the sound as changing the tubes change the sound profile. What engineers call better, and what audiophiles call better may be two different things, as clinically accurate may not always sound the best. Sound is very subjective. I use this amp with the Sennheiser 6xx and it sounds quite satisfying, although in certain songs, I can hear some distortion/crackling at regular volume although such instances are very rare.


----------



## edulov

sup27606 said:


> They didn't say the tubes are there for show. The tubes are not used for real amplification, but used as buffer which color the sound possibly by introducing some distortion. The tubes have an effect on the sound as changing the tubes change the sound profile. What engineers call better, and what audiophiles call better may be two different things, as clinically accurate may not always sound the best. Sound is very subjective. I use this amp with the Sennheiser 6xx and it sounds quite satisfying, although in certain songs, I can hear some distortion/crackling at regular volume although such instances are very rare.


 

 The buffer means a closed loop needed to give a higher amplification coefficient for op amps with some indirect processing of harmonics due to "how vacuum valve works". In usual HiFi-type solutions, the buffer is implemented by another op amp (mostly of the different reference) to generate reacher sound. That is why in my case I rolled both: tubes and op amps.
  
 About distortions (checked in my setup):
 1) Not tightly plugged PSU moved accidentally; Easy to solve;
 2) USB Jitter affects USB DAC decoding - mostly. You may need some voodoo up to switching to HQ motherboard (in case of desktop)
 3) EM wave mutual influence from other devices and cables. Buy HQ shielded audio cables.


----------



## dr3wd4wg

I purchased some NOS Mullard E180F tubes on Ebay (http://www.ebay.com/itm/5-Pcs-NOS-Mullard-E180F-6688-audio-radio-Preamp-Tubes-NIB-/290900841002?hash=item43bb0a922a). I have to wait till after the New Year before they ship
	

	
	
		
		

		
			





.  They look like early to mid 70's. Anybody else try these?


----------



## joemg

after doing a lot of googling on this, as I posted in another thread, this video shows that the tubes are only used as a buffer and not for actual amplification in these units: https://www.youtube.com/watch?annotation_id=annotation_369287791&feature=iv&src_vid=9RhD-NO0n-4&v=coSt5HWRvv4
  
 That's not to say they don't sound good, but I just thought I'd spread that information so anyone considering purchasing one (as I was) has all the facts.
  
 (The video shows a Xuanzu branded unit, but I believe it's just rebranded)


----------



## trellus

That's rather normal and expected at this price point. I had one of these and the tubes definitely color the sound even though they aren't doing the amplification.



joemg said:


> after doing a lot of googling on this, as I posted in another thread, this video shows that the tubes are only used as a buffer and not for actual amplification in these units: https://www.youtube.com/watch?annotation_id=annotation_369287791&feature=iv&src_vid=9RhD-NO0n-4&v=coSt5HWRvv4
> 
> That's not to say they don't sound good, but I just thought I'd spread that information so anyone considering purchasing one (as I was) has all the facts.
> 
> (The video shows a Xuanzu branded unit, but I believe it's just rebranded)


----------



## joemg

trellus said:


> That's rather normal and expected at this price point. I had one of these and the tubes definitely color the sound even though they aren't doing the amplification.


 
  
 yes, I agree... but you also have units like the Bravo V1 & V2 that are true tube amps for $60/70.  Again, I'm not knocking the amp, I was a click away from buying it myself after reading reviews... but when I got all the facts, I was a little bummed out so I wanted to make sure everyone had them before making their own decision to buy.
  
 After an absurd amount of research for a $50 amp, I finally just caved in and went with the Fiio E10k.  Amazon had it on warehouse deals, used, for $50.  I needed a DAC too, so there just was no beating this value for the money for me personally.  It's nowhere near as cool looking as the nobsound though, lol.


----------



## edulov

This is a hybrid amp, the amplification is made by pair op amp and valve. Other relatively cheap headphone amps with valves also are hybrid ones. Also, most of them are using triodes (pure ones). This one uses pentode as triode, but due to tube design, it gives reacher, more vivid sound.
 Since I have Fiio E10K for a long time now, I made a direct comparison after a tube rolling. Everything is better, just everything, especially highs and extension and control of lows. And even after tube and op amp rolling (maybe I was lucky to buy valves really cheap) the total cost of 08E was less then Fiio's.
  
 BTW, I needed a good amp for all fine hp range (32 Ohm up to 600 Ohm) with a plenty of power. Too many amps prised here actually can't drive 250 Ohm cans: they lack resolution and control. Not even counting for 600Ohm cans.


----------



## Audiophilic10

sup27606 said:


> They didn't say the tubes are there for show. The tubes are not used for real amplification, but used as buffer which color the sound possibly by introducing some distortion. The tubes have an effect on the sound as changing the tubes change the sound profile. What engineers call better, and what audiophiles call better may be two different things, as clinically accurate may not always sound the best. Sound is very subjective. I use this amp with the Sennheiser 6xx and it sounds quite satisfying, although in certain songs, I can hear some distortion/crackling at regular volume although such instances are very rare.


 

 Hello sup27606,
 yes, they didn't say tubes are for show (that would be having just a glowing tube doing nothing) but they elaborate that tubes were included into the design for the sake of having/showing tubes there... that's what I don't like so much. I don't want to diss the amp as for the price it seems a bargain and it's been stated to work, but were I to get a tube amp I'd prefer one built properly around tubes.


----------



## joemg

edulov said:


> This is a hybrid amp, the amplification is made by pair op amp and valve. Other relatively cheap headphone amps with valves also are hybrid ones. Also, most of them are using triodes (pure ones). This one uses pentode as triode, but due to tube design, it gives reacher, more vivid sound.
> Since I have Fiio E10K for a long time now, I made a direct comparison after a tube rolling. Everything is better, just everything, especially highs and extension and control of lows. And even after tube and op amp rolling (maybe I was lucky to buy valves really cheap) the total cost of 08E was less then Fiio's.
> 
> BTW, I needed a good amp for all fine hp range (32 Ohm up to 600 Ohm) with a plenty of power. Too many amps prised here actually can't drive 250 Ohm cans: they lack resolution and control. Not even counting for 600Ohm cans.




I'm genuinely curious about your findings:

When you compared the e10k and the 08e, were you using the dac on the e10k vs a different dac for the 08e or does the e10k give a line out? (Mine hasn't arrived yet)

I'm almost wondering if I should order both and just return the one I don't like as much... but then I'd need a dac too for the o8e...


----------



## sup27606

audiophilic10 said:


> Hello sup27606,
> yes, they didn't say tubes are for show (that would be having just a glowing tube doing nothing) but they elaborate that tubes were included into the design for the sake of having/showing tubes there... that's what I don't like so much. I don't want to diss the amp as for the price it seems a bargain and it's been stated to work, but were I to get a tube amp I'd prefer one built properly around tubes.


 
  
 They are using the tubes for coloring the sound instead of using them directly for amplification. The main task of amplification is done by the op-amps. Thats what I understand from the video. What the presenter (and the specialist he consulted towards the end) was saying was that, including the tubes probably introduced more distortion than not including them, which is probably true. In a way, adding the tubes is probably superfluous to the design. However I like how changing the tubes changes the sound profile, for example from the stock ones to the Mullard 6688s. What I find problematic about the video is, there is not a single mention of actual sound quality besides all the technical talks. They also did not bypass the tubes and compared whether the sound is better or worse without the tubes. Also, there is a general contempt towards audiophiles (the presenter refers to them as audiofools at one point).
  
 I am also not sure, how much I can emotionally connect with pure clinical sound. Is it even necessary for enjoying music? While listening to music through loudspeakers under practical conditions, or in a concert hall, there is always distortion present due to acoustics. Still such music is enjoyable.
  
 BTW, after seeing your post, I was curious about the Bravo V1, so I went ahead and ordered one. These amps are supposed to use only the tube for amplification, without any ICs. I will post the comparison with the Nobsound once I listen to both.


----------



## Audiophilic10

I agree on all you say, it would've been good some talk about sound on their part. I look forward to your findings!


----------



## LazyListener

Does this amp benefit from burn in?  Has anyone noticed a change in sound over time?  Also, do the tubes require burn in or warming up to sound best?  If so, how long, and is it a one time thing or after each cool down and power up cycle?


----------



## sup27606

I don't know about the burn-in, but the tubes should be warmed up to the recommended 15 sec every time before plunging in the headphones. Otherwise there will be a sharp transient sound through the phones which is not pretty.


----------



## LazyListener

sup27606 said:


> I don't know about the burn-in, but the tubes should be warmed up to the recommended 15 sec every time before plunging in the headphones. Otherwise there will be a sharp transient sound through the phones which is not pretty.


 

 Thanks!  Where do you get the 15 sec recommendation from?  I didn't get a manual or any documentation with mine with any recommendations.  Is that just a thing for tubes in general?
  
 I just got mine and I have to say I'm not too thrilled initially.  It's too bright sounding for my taste.  My Magni 2 sounds much more neutral and smooth.  I know I can buy other tubes to change the sound but was hoping I wouldn't have to.


----------



## edulov

sup27606 said:


> I don't know about the burn-in, but the tubes should be warmed up to the recommended 15 sec every time before plunging in the headphones. Otherwise there will be a sharp transient sound through the phones which is not pretty.


 
 Burn-in - no need, 20-30 sec for warming. I tried to catch the differences after extended warming (>3 mins) but on the edge of fooling myself. It looked that extended lows became slightly better controlled and full-bodied, but you need special test tracks and good cans. So if you are not a hardcore bass-head - just ignore or wait a couple of minutes.


----------



## edulov

For LazyListener:
 Amp comes with cheap horrible vacuum tubes. ANY other is better. Just take into account that not all tubes provide really extended, "clean" lows if you want to hear bass where track comes with them. Just do not forget that you will need good cans to catch the difference. If yours will show signs of muddiness and became boomy at lows or on the contrary became too harsh at highs it is just the sign to get better headphones before fine tube rolling or even op amp switching.


----------



## sup27606

lazylistener said:


> Thanks!  Where do you get the 15 sec recommendation from?  I didn't get a manual or any documentation with mine with any recommendations.  Is that just a thing for tubes in general?
> 
> I just got mine and I have to say I'm not too thrilled initially.  It's too bright sounding for my taste.  My Magni 2 sounds much more neutral and smooth.  I know I can buy other tubes to change the sound but was hoping I wouldn't have to.




Please see this link for the 15 sec recommendation:
http://www.doukaudio.com/Product/detail/id/7.html

Strange that you find it bright sounding. For me, it had warm sound with very deep lows and good soundstage. The stock tubes had poor treble response, so I replaced them with tubes as recommended in this forum. Now it sounds quite pleasant.


----------



## sup27606

edulov said:


> Burn-in - no need, 20-30 sec for warming. I tried to catch the differences after extended warming (>3 mins) but on the edge of fooling myself. It looked that extended lows became slightly better controlled and full-bodied, but you need special test tracks and good cans. So if you are not a hardcore bass-head - just ignore or wait a couple of minutes.




It's an analog device, so I have no problem in believing what you are hearing. There may be some marginal improvements after extended warming. I think the 15 sec recommendation is based on the time when it approaches near optimal sound, like 95% of steady state sound or something. Also, is it possible that different tubes have different heating times?


----------



## LazyListener

sup27606 said:


> Please see this link for the 15 sec recommendation:
> http://www.doukaudio.com/Product/detail/id/7.html
> 
> Strange that you find it bright sounding. For me, it had warm sound with very deep lows and good soundstage. The stock tubes had poor treble response, so I replaced them with tubes as recommended in this forum. Now it sounds quite pleasant.


 

 I think I'm sensitive to brightness.  It does sound warm down low with good bass, but too bright up top.  I agree, soundstage is pretty good, but some background sounds are a bit harder to hear than with other amps.
  
 I just swapped from it to E10K, and I actually prefer the sound of the E10K.  More neutral and balanced sounding.  Bass isn't as pronounced.  Soundstage is just as good, if not better.  No issue with not being able to hear background sounds.
  
 I'm using HD 650 for testing.
  
 I will have to consider different tubes, but I really, really didn't want to get into swapping tubes right away.


----------



## edulov

To LazyListener:
  
 Before going into the discussion I checked my FR database about HD650. It seems that there exist 2 completely different versions. One - you may call balanced and good, the other one has really bad lows and horrible treble. For me, it was a reason to ignore this cans. So w/o knowing which one is yours, a discussion is meaningless. Its Senn's fault, not yours.
  
 1. Some call the sound bright not taking into consideration that DAC, amp, hp's or spk's are honest and that it a real track sound, how it was meant to be. Or mess up brightness with sibilance.
 2. Since hp amp's soundstage is one of the cornerstones to differ between regular and better ones, I spent some time testing different tracks, amps and cans. My setup is times better then E10K. Also, this Fiio has one "undocumented" feature: quite bad THD at middle and especially high treble. Only after owning several good hp's I confirmed this instrumental measurement bu ear. But going back to soundstage: after tube rolling 08 offers not just a width, but depth and even slightly heights. I was really surprised how some tracks sounded afterwards being capable to locate instruments and vocals. At the same time I'd say 95% of tracks showed miserable width, no depth. SO bad tubes is the best choice to stay away from knowledge of being fooled. BUT! You'll need a really good set of open cans too hear that.
 3. For the price Fiio E10K offers good lows, but tube rolling gave me extension, body and control. Actually after hearing some tracks after "tuning" I deleted them surprised how bad they sound at lows when you can really hear below 100 Hz.
  
 PS. About Senn's. Some old school 4xx and 5xx open cans are much better than any of the 6xx series.


----------



## LazyListener

edulov said:


> To LazyListener:
> 
> Before going into the discussion I checked my FR database about HD650. It seems that there exist 2 completely different versions. One - you may call balanced and good, the other one has really bad lows and horrible treble. For me, it was a reason to ignore this cans. So w/o knowing which one is yours, a discussion is meaningless. Its Senn's fault, not yours.
> 
> ...


 

 I don't think I have bad 650s because they sound just fine with E10K and with Magni 2.  Even with my iphone they don't sound too bright.  (No, I don't use 650 with iphone, just for testing.)  Only with the 08e amp do they sound too bright (lows are fine).  I don't think it's sibilance as "S" sounds normal, not sharp.  It's a broader frequency range in the highs.  Also it's not specific songs.  It's every song.  Too bright.  Only with 08e amp.
  
 I have other cans I can try with the 08e to check the brightness.  Maybe I'll do that later, but I got this amp primarily for use with 650.


----------



## sup27606

lazylistener said:


> I don't think I have bad 650s because they sound just fine with E10K and with Magni 2.  Even with my iphone they don't sound too bright.  (No, I don't use 650 with iphone, just for testing.)  Only with the 08e amp do they sound too bright (lows are fine).  I don't think it's sibilance as "S" sounds normal, not sharp.  It's a broader frequency range in the highs.  Also it's not specific songs.  It's every song.  Too bright.  Only with 08e amp.
> 
> I have other cans I can try with the 08e to check the brightness.  Maybe I'll do that later, but I got this amp primarily for use with 650.




The phones I use most with the 08e are the 650s (massdrop 6xx which are rebranded 650) and I didn't find any unusual brightness. 650s have more polite trebles than other phones, so if the 650s sound bright with your amp, I wonder how the brighter cans like AKGs and ATHs would behave. This leads me to speculate, if there is anything wrong with the amp. BTW, I tested another phone with this amp, the Audeze Sine which has more pronounced treble than the 650s and even that didn't sound bright at all.

BTW, I understand E10K has a built in DAC. Which DAC are you using with the 08e? Since the E10K did not sound bright to you, can you connect the pre-out of E10 to the 08e. That way, you know it's 08e that's causing the issue. Also make other people listen to the amp and get their verdict.


----------



## LazyListener

sup27606 said:


> The phones I use most with the 08e are the 650s (massdrop 6xx which are rebranded 650) and I didn't find any unusual brightness. 650s have more polite trebles than other phones, so if the 650s sound bright with your amp, I wonder how the brighter cans like AKGs and ATHs would behave. This leads me to speculate, if there is anything wrong with the amp. BTW, I tested another phone with this amp, the Audeze Sine which has more pronounced treble than the 650s and even that didn't sound bright at all.
> 
> BTW, I understand E10K has a built in DAC. Which DAC are you using with the 08e? Since the E10K did not sound bright to you, can you connect the pre-out of E10 to the 08e. That way, you know it's 08e that's causing the issue. Also make other people listen to the amp and get their verdict.


 

 I used the E10K DAC line out with the 08e and Magni 2 in my testing.  I think I'm just sensitive to certain mid-treble frequencies when they're overemphasized relative to the rest of the spectrum.  This is also why 598 are my favorite cans - everything is softer, more laid back with them, and never, ever harsh, but still quite detailed.  I'm gonna try them next with the 08e and check for the brightness.


----------



## erich6

edulov said:


> Valve compatibility is not a secret. Even on eBay, you will find correct cross-references trying to search for 6j9p (6g9p), both are the transliteration of a Cyrillic letter "Ж". I know about one another 100% electrically compatible lamp, but dunno how it sounds, still planning to try it on. Also, there are some more from the same "family" 6ж, partially compatible.


 

 ​Thanks for all the inputs/analysis you've made to this thread.
  
 Can you say specifically why the 12AX7 is incompatible despite having the same 9-pin interface? Is it because the way the twin-triode of the 12AX7 interfaces with the amp vs. the pentone architecture of the 6j9?


----------



## MisterMudd

prohobo said:


> jajajaja
> 
> So there is a reason they call this amp NOBsound - I guess I am the NOB?!?!?!
> 
> ...



E180F works. I am using Millard.

Edit: Mullard


----------



## erich6

Well, I checked the data sheets for the 12AX7 and the 6688's and I think I answered my own question.  Different pin assignments and circuits altogether so don't expect them to be interchangeable.


----------



## edulov

E180F is a full analogue valve. 12AX7 is completely different. Compare pin layout yourself
 1. http://3.bp.blogspot.com/_VuFNYQK52XE/TUwT1JxygII/AAAAAAAAAWY/E6VCYUkLEDc/s1600/05309.png
 2. http://www.r-type.org/pdfs/e180f.pdf


----------



## edulov

598 are better for mids and much better for treble than 650, but not so good for lows (not that bad at the same time). And they sound softer if you have sensitive ears.


----------



## erich6

So searching the internet for replacement tubes for this amp I see several sellers group the 6688/E180F as almost a generic NOS from "various manufacturers" which seem to include Sylvania, RCA, Marconi, and Siemens.  Are they all equivalent and just a "rebranding"?
  
 The ones that seem to be normally called out separately are:
  
 Amperex
 GE (JAN)
 Philips
 Mullard
 Telefunken
  
 I guess the STC 5A/170K​ is also equivalent?
  
 That's not counting the Russian and Chinese types.


----------



## henkeman

What op amps might work good with NS-08E besides LT1364CN8, NE5532, OPA2107 and AD823ANZ ?


----------



## henkeman

The tubes are not all the same. They have different characteristics. The chinese ones and the E180F that I have are very different. MyE180F are clearer with better soundstage, bass, treble etc.


----------



## edulov

henkeman said:


> What op amps might work good with NS-08E besides LT1364CN8, NE5532, OPA2107 and AD823ANZ ?


 
 When I decided to play with op amps I started my search with compatibility lists for NE5532/DIP8 package, looking for the description of sound signatures and checking whitepapers for electric/specs compatibility.
 Complete list is much wider, but I excluded a lot of options due to strong colorization of sound signature (dark and veiled especially), lacking clarity for treble and lacking extension/control for lows.
  
 But may be you want the opposite, like dark sound and cut-off for treble?


----------



## henkeman

edulov said:


> When I decided to play with op amps I started my search with compatibility lists for NE5532/DIP8 package, looking for the description of sound signatures and checking whitepapers for electric/specs compatibility.
> Complete list is much wider, but I excluded a lot of options due to strong colorization of sound signature (dark and veiled especially), lacking clarity for treble and lacking extension/control for lows.
> 
> But may be you want the opposite, like dark sound and cut-off for treble?


 
 I want it to sound natural and musical with neutral clarity(not to analytical) good soundstage bass ext. But im also sensitive to treble. Have a pair of X2:s which are great besides some treble problems in certain tracks.


----------



## edulov

To henkeman:
  
 I wanted the same, so LT1364CN8 (CN8 denotes packaging) became my choice. All I can say that both LT and NE are honest in treble, so a bright track will sound bright; but no special emphasis to be heard. Just do not use tubes  providing "lean" sound, since they tend to be way too honest with high treble.


----------



## dr3wd4wg

I tried the LT1364 and found them too bright. The LM4562's I use now with Mullard E180F maintains the characteristics of the 5532 with (IMHO) less treble roll off and lower THD and noise. I might replace the 6V power supply, as even placing my phone near the amp causes all sorts of noise.


----------



## edulov

dr3wd4wg said:


> I tried the LT1364 and found them too bright. The LM4562's I use now with Mullard E180F maintains the characteristics of the 5532 with (IMHO) less treble roll off and lower THD and noise. I might replace the 6V power supply, as even placing my phone near the amp causes all sorts of noise.


 
 Agree


----------



## henkeman

Ok i really like the current sound profile of 5532:s and my valvo e180f so i might buy the LM4562 to since they where cheap from trusted source.I have lt1364 on the way from china (hope they are not fake). Will LT1028 work do you think? Im also contemplating upgrading the power supply but im not sure to what since I dont want to spend to much money on it compared to the amp.


----------



## erich6

I can confirm the Amperex JEP-6688's are great (mine are from 1964 production).  I also rolled a pair of NOS Lorenz E180Fs and they have the same tonality as the Amperex but slightly more expansive sound and bass control at the expense of slightly more microphonics (really only a little more which I only notice when something touches the amp).  Either pair is a great match.
  
 I tried a pair of Telefunken E180F (1968 production) and I was very disappointed...they sounded the same if not worse than the Chinese stock tubes.  It could be I just got a bad pair though. Anyone else try these?
  
 I'm still very impressed with this hybrid amp.  It's main issues are the poorly isolated power supply and short power chord...otherewise it's fantastic.


----------



## erich6

henkeman said:


> Ok i really like the current sound profile of 5532:s and my valvo e180f so i might buy the LM4562 to since they where cheap from trusted source.I have lt1364 on the way from china (hope they are not fake). Will LT1028 work do you think? Im also contemplating upgrading the power supply but im not sure to what since I dont want to spend to much money on it compared to the amp.


 

 ​I've been eyeing the Valvo as something to try.  They seem to be double the price of Amperex or Lorenz tubes though.  Have you been able to compare the Valvo's to other 6688/E180F tubes?


----------



## henkeman

erich6 said:


> ​I've been eyeing the Valvo as something to try.  They seem to be double the price of Amperex or Lorenz tubes though.  Have you been able to compare the Valvo's to other 6688/E180F tubes?


 
 I  have only got the Valvos:s and the chinese ones. I got mine from ebay.de for like $5 each including shipping so for me it was cheaper then the Amperex 6688 which I wanted to buy first hehe. But compared to the chinese ones its like lifting of a veil and all of the music sounded so much better and more balanced and clear.
  
 I bought 4 pc of czech made E180F Tesla yesterday from ebay because they looked so well done quality wise and was cheap. I read some where that they where really good but kind of "forgotten".. Cant wait til I get them so I can compare them with the Valvo:s.


----------



## erich6

henkeman said:


> I  have only got the Valvos:s and the chinese ones. I got mine from ebay.de for like $5 each including shipping so for me it was cheaper then the Amperex 6688 which I wanted to buy first hehe. But compared to the chinese ones its like lifting of a veil and all of the music sounded so much better and more balanced and clear.
> 
> I bought 4 pc of czech made E180F Tesla yesterday from ebay because they looked so well done quality wise and was cheap. I read some where that they where really good but kind of "forgotten".. Cant wait til I get them so I can compare them with the Valvo:s.


 

 ​$5 !!  I'm seeing them consistently for $80+ a pair.
  
 Yeah, I was thinking about trying the Teslas also.  Look forward to your impressions.


----------



## henkeman

erich6 said:


> ​$5 !!  I'm seeing them consistently for $80+ a pair.
> 
> Yeah, I was thinking about trying the Teslas also.  Look forward to your impressCurr


 
 Currently there are a pair for like $16 http://www.ebay.de/itm/Rohren-2x-E180F-Valvo-neu-Gold-Pin-/132049274040?hash=item1ebec004b8:gfYAAOSw241YZo-H 
  
 I think that "private persons" sell them much cheaper then commercial sellers. I dont know if they are different then the commercial ones. But mine looks exacly like the ones that sells for $80. There seems to be at least two different models but they are of the same high price from the commercial sellers.I have both models and they sounds about the same.


----------



## henkeman

I must say that my k550 have never sounded better then with this amp and good tubes no more trebleness and I cant believe that they are closed headphones. The soundstage got so huge but still natural! The tone is so nice, especially with rather calm "soundless" music with few instruments and vocalists(for more energetic music I prefer the open cans). Its like a pitch black background and the sounds/music just emerges from nothing at goes back to nothing so effortlessly with details that Ive never heard before, so natural.
  
 They are only 32 ohms but this is the most synergistic combo I tried so far (before I didnt like my k550s so much). Tried Fidelio X2, AKG k612 and K712. But the k550 seems to benefit the most of this amp at least to my ears.


----------



## Tom Steed

I put a pair of 50yr old new mullard e180f's into this little box and it sounds great. I use sony mdr1 phones which are punchy on the mid to high range. They've mellowed a lot, i am going to invest in another pair of headphone, just need to find some that suit me.also i will be 'rolling' the op amp's and will have a few pair arriving soon. namely OPA3604AU and LM4562NA. I want to see what they sound like.


----------



## edulov

tom steed said:


> I put a pair of 50yr old new mullard e180f's into this little box and it sounds great. I use sony mdr1 phones which are punchy on the mid to high range. They've mellowed a lot, i am going to invest in another pair of headphone, just need to find some that suit me.also i will be 'rolling' the op amp's and will have a few pair arriving soon. namely OPA3604AU and LM4562NA. I want to see what they sound like.


 
 Small advice about rolling opamps. Wait about 30 sec after switching on but w/o sound playing at mid-high volume for your headphones. If you will hear some persistent silent noise or light whistling - electrical specs of opamps are not in sync with tubes and you can't use this pair. Wish you luck.


----------



## Tom Steed

Thanks for the heads up, they're cheap enough to play with i wouldn't try with muses chips though..


----------



## lyncks

Hey everyone
  
 how does it do with the AKG K7xx? good match?
  
 Cheers


----------



## DJ The Rocket

dangerclose said:


> Some of my larger 3.5mm might be a close fit, but they fit.  It's adapters that can be a problem. It's a minor thing, but it's a thing.
> 
> If this isn't considered kind of hot, then the Schiit Magni is like in a freezer.  It's not even close to the temperature my NS08 gets.  Does such a temperature difference matter?  Is the NS08 designed to operate fine for decades at the higher temp?  Does my particular NS08 run hotter than yours for some strange reason?  Who knows.




Huh. I thought it sounded absurd t say you weren't able to make the 6.35mm to 3.5mm adapter work, but I tried mine directly, and what do you know, it doesn't fit! I've been using a silver-plated extension cable ($16 for 6' on Amazon) and I can't detect any loss of sound quality with it, even on my Norse Audio cabled LCD2.2s, and I easily can with generic extension cables (though the 6.35/3.5 adapter there may be a weakest link: better than the 6' silver plated cable, but worse than the Norse).

EDIT: I also wanted to mention that this 3.5mm jack doesn't seem to do well with TRRS cables--even using a TRRS extension cable with a TRS plug on the other end, not talking about anything with a mic or remote on it. My TRRS extension works, but it serms to become unseated too easily. Don't see that issue with TRS plugs. It's unfortunate that my good extension is TRRS, I had assumed I'd be covering all the possibilities with this one cord, guess it's more complicated than that


----------



## DJ The Rocket

henkeman said:


> I  have only got the Valvos:s and the chinese ones. I got mine from ebay.de for like $5 each including shipping so for me it was cheaper then the Amperex 6688 which I wanted to buy first hehe. But compared to the chinese ones its like lifting of a veil and all of the music sounded so much better and more balanced and clear.
> 
> I bought 4 pc of czech made E180F Tesla yesterday from ebay because they looked so well done quality wise and was cheap. I read some where that they where really good but kind of "forgotten".. Cant wait til I get them so I can compare them with the Valvo:s.




Care to update us on the forgotten Teslas?


----------



## henkeman

Im sorry for the late post. I have continued my tube explorations and gotten a Little Dot MK3 so I have not been using my nobsound so much lately. Been burning in the Tesla:s under the weekend for about 20hrs so I can give my honest impressions.
  
 When I first got them the treble was really shrill and bad and I didnt think any burn in could possibly change that.
 I got disappointed and popped in the Valvos again and have not touched the Teslas since. Now I must say I really like them after the burn-in! No more harshness in the treble as heard before.
  
 I do not have time to compare direct side by side with the Valvos but from memory I must say they are about as good. Separation soundstage and treble is really good and sweet! In some ways I prefer this amp with the Teslas to the little dot with russian Voskhod  6j1p-ev tubes. It has a nice fullness to the sound and the harmonics are so nice!
  
 Im sorry I cant give a more detailed review of the tubes. They sound good and look really good and are nicely made to! At the price point I think it is a good buy.


----------



## erich6

henkeman said:


> Im sorry for the late post. I have continued my tube explorations and gotten a Little Dot MK3 so I have not been using my nobsound so much lately. Been burning in the Tesla:s under the weekend for about 20hrs so I can give my honest impressions.
> 
> When I first got them the treble was really shrill and bad and I didnt think any burn in could possibly change that.
> I got disappointed and popped in the Valvos again and have not touched the Teslas since. Now I must say I really like them after the burn-in! No more harshness in the treble as heard before.
> ...


 

 ​Thanks for sharing your findings! Also, thanks for the comparison to the Little Dot Mk3 as I've been wondering if it would be an upgrade to the Nobsound.  I really like the sound I'm getting from this little amp but the microphonics and poor power isolation sometimes gets to me.


----------



## henkeman

erich6 said:


> ​Thanks for sharing your findings! Also, thanks for the comparison to the Little Dot Mk3 as I've been wondering if it would be an upgrade to the Nobsound.  I really like the sound I'm getting from this little amp but the microphonics and poor power isolation sometimes gets to me.


 
 For me I consider the LD3 an upgrade. But if its worth x6 the price of the nobsound I dont know. The nobsound is really a budget king in my opninion.
  
 In some music I enjoy the nobsound more for example hard rock and more energetic music like Rodrigo y Gabriela which I think benefits from the fuller and actually softer sound of the nobsound. I guess the nobsound could be considered more fun but it doesn't suck me in as the LD3 does with my K712:s at least.
  
 I mostly listen to jazz, classical, instrumental, bluegrass and female vocalists that benefits the biggest in realism in the sounds of the music and soundstage of the LD3. Other improvements that I could discern in the LD3 was a cleaner sound compared the nobsound sounds a bit grainy and noisy especially if you have to push the volume. It might be that a better ps or batteriy power could remedy that a bit. I guess one could say that the LD3 with the Voshods at least is more clean and hifi. But its a matter of degrees not like night and day. In the end I think its just a matter of how much one could enjoy the music one likes and hear beauty in it and how much one can spend on gear, to me the LD3 gives me more enjoyment.


----------



## edulov

Too subjective.
 Due to the valve types used in LD3, it is intended to sound drier (analytical) which more people qualify as better HiFi. People mistake forced lack of harmonics with true HiFi.
 Mine Nob is not either noisy, either grainy or softy + HQ audio and USB cables. Also I never considered 712 since they fail in high treble. Considering their cost it becomes a deadly flaw.
 So I just won't consider this mentions as relevant. (no abuse, just tech specs).


----------



## henkeman

edulov said:


> Too subjective.
> Due to the valve types used in LD3, it is intended to sound drier (analytical) which more people qualify as better HiFi. People mistake forced lack of harmonics with true HiFi.
> Mine Nob is not either noisy, either grainy or softy + HQ audio and USB cables. Also I never considered 712 since they fail in high treble. Considering their cost it becomes a deadly flaw.
> So I just won't consider this mentions as relevant. (no abuse, just tech specs).


 
 It might come down to what one prefers and hears... I only gave my opinions based on my own hearing observations, preferences and knowledge at the given moment. Yes the harmonics in the nobsound are really good, but I  dont think they mean everthing in music. There is allways an element of balance that is needed.
  
 To me the LD3 sounds more realistic and true to real sound as heard i real life performances etc. But please enlighten me to what "true HiFi" is because I really dont know what else it could be.
  
 I really think there is something special with the triode strapped pentode and I happily will use it again. Maybe I will be disenchanted by the LD3 and find that I like the nobsound more. I dont know, but right now Im able to enjoy music more with the LD3.
  
 In the beginning I was disappointed with the LD3 because the thin analytical sound. But with higher gain and headphones that are fuller by nature they are really sublime. I will replace the Voshods with a more tubey sounding tubes.
  
 I only heard the noise/grainyness in direct comparison with the LD3. If I hadnt done the comparison I would have thought it was in the recording or something further upstreams. I only have the stock op-amps in the nobsound.
  
 I dont have any high treble problem with my k712, there might be a spike somewhere but nothing I could discern with my hearing. I think there might be different kinds of k712 or it is all subjective based on ones hearing. Some say they are bass weak/strong, mine are bass strong, some say they are dry, mine are not dry at all. They seem to pick up harmonics for good and bad. Some say they have treble problems mine dont. Some say they are thin or full, mine are full. I only gave $200 for my pair compared to the $220 i gave for mi HD600 which in my opinion are inferior in every way except balance. Modded my K712 by placing a pair of Fidelio X2 earpads on top of the stock ones an that brought balance so now I will sell the HD600s,


----------



## DJ The Rocket

edulov said:


> *Rolling tubes.*
> Before anything else please understand that 6ж9п valve have many direct analogues and highly compatible ones also. Due to fabrication processes and materials they are not identical, so the devil hides in details. But first of all here is a list of all references, especially if you will look for them at eBay:
> 6ж9п, 6j9p, 6g9p, 6zh9p, 6ж9п-Е, 6j9p-e, 6g9p-e, 6zh9p-e, [COLOR=00000A]5A/170K, 6688, 6688A, CV3998, CV6189,[/COLOR][COLOR=00000A]E180F[/COLOR]
> [COLOR=00000A]Adding suffix letter usually means long life version of tube, also with refined specs.[/COLOR]
> ...




I'm looking at a pair of GE 6688 ($14/pair) and regular Amprex 6688 ($22). Can you (or anybody) tell me if you feel the difference in quality is enough to be worth $8?


----------



## edulov

About GE and Amperex/RCA/Mullard
  
 GE offers more analytical sound w/o emphasis in lows and not so extended in lows.
 Since one part of the music, I'm listening "kicks" and I prefer open/semi-open cans which slightly lack bass, I keep GE's for special occasions.
 But if you prefer closed hp's, especially bass focused, GE's might offer you balance.


----------



## TheBIGKill1998

Heya guys, first of all, im new and this is my first post. And this is just meant to be a little reply containing my current experience with this amp. 
  
 To make 1 thing clear at the beginning, it is not a "real" hybrid tube amp, since the tubes are not directly used for pre-aplification, they are simply used as input buffers. 
 (still it is a great little amp tho, with a nice charme of tube flavour in the sound) 
  
 I use this amp at my PC with the Behringer U-Control UCA222 USB Audio Interface as DAC. 
 In my setup this little amp sounds pretty good for what it did cost.
  
 Currently im using russian 6j9p tubes, which sound pretty awesome, whilst being relatively cheap (i got 10 of those for 20 euros including shipping costs).
 I exchanged the op amps of it with LM4562NA ICs. I highly recommend those since they deliver more details than the stock ones. 
  
 Before i used Tesla E180F tubes, which i personally did not like much.
  
  
  
*To sum this all up, here's a little list of things i recommend when you're using this amp:*
  
 - Exchange the opamps (maybe with the ones i named earlier)
 - Use other tubes (i recommend the russian 6J9P ones)
 - Use a DAC
 - remove the blue LEDs (i just think it looks sooooo much better without them) 
  
 - if you decide to change the opamps, dont use/buy the OPA2604 ones.... i tried them.... and they seem to NOT match the electrical specs of the amp. I had constant weird noises coming out of my headphones, when i tried them out.


----------



## henkeman

Are these the 6J9P or the 6J9P-E you are using? How would you say they compare to the Teslas?
  
 Popped in my Valvos again and concluded I liked them more than the Teslas.


----------



## TheBIGKill1998

henkeman said:


> Are these the 6J9P or the 6J9P-E you are using? How would you say they compare to the Teslas?
> 
> Popped in my Valvos again and concluded I liked them more than the Teslas.


 
 Hello,
  
 I'm using the normal 6J9P Tubes and they sound pretty great. But the only difference between 6J9P and 6J9P - E Tubes, is that the 6J9P - E ones have a longer lifespan and are better built.
  
 Well, compared to the Teslas i would say, that the Teslas seem to be kinda muddy and with less Detail. I would say that the 6J9P Tubes sound pretty analytical. They have plenty Detail, whilst keeping up the typical tube warmth.
  
 But do not only focus on Tube Rolling. Rolling the Opamps changes the sound by quite a lot and can also improve it by far.


----------



## DangerClose

thebigkill1998 said:


> I'm using the normal 6J9P Tubes and they sound pretty great. But the only difference between 6J9P and 6J9P - E Tubes, is that the 6J9P - E ones have a longer lifespan and are better built.


 
  
 Have you tried both kinds?  I would say there's a clear difference.  Though one of my sets had more hours on them than the other, so that could have been a factor.  Before trying them, I had also read at least a couple people around the internet say they sound different.
  
 There's different 6j9p too.  I have some taller ones, and some shorter ones.  All labeled 6j9p (or foreign language equivalent).  Those sound different too, though, again, some had more hours than the others.


----------



## TheBIGKill1998

dangerclose said:


> Have you tried both kinds?  I would say there's a clear difference.  Though one of my sets had more hours on them than the other, so that could have been a factor.  Before trying them, I had also read at least a couple people around the internet say they sound different.
> 
> There's different 6j9p too.  I have some taller ones, and some shorter ones.  All labeled 6j9p (or foreign language equivalent).  Those sound different too, though, again, some had more hours than the others.


 
 No i have not tried both types. I am just saying what i know from their Descriptions. 
  
 The taller ones are a different type then. 
 But yeah, since the 6J9P-E Tubes are built differently (in general better built with a longer life span) it sure is possible that they sound different.
 I just did not know about that for sure.
  
 Which ones sound better in your opinion?
  
 If they really sound different, i really have to try them out!


----------



## Brian Coffey

What Op Amps seem to work best with this amp so. And is it a single or a dual?


----------



## TheBIGKill1998

brian coffey said:


> What Op Amps seem to work best with this amp so. And is it a single or a dual?


 
 It uses 2 ne5532 dual op amps. I exchanged them with the lm4562 op amps. 
 Just looking at the electronic specs they are almost a perfect match.
 I think that they outperform the stock ones (ne5532) in each category.


----------



## Brian Coffey

thebigkill1998 said:


> It uses 2 ne5532 dual op amps. I exchanged them with the lm4562 op amps.
> Just looking at the electronic specs they are almost a perfect match.
> I think that they outperform the stock ones (ne5532) in each category.


 
 Thank You! May order a couple this weekend.


----------



## TheBIGKill1998

brian coffey said:


> Thank You! May order a couple this weekend.


 
 You are welcome!


----------



## fjhuerta

I was wondering if anyone has noise issues with this amp. I just got mine and it has this noise. It's not  a 60 Hz hum, it's like surface noise on vinyl. It's very noticeable. It goes out whenever I take out the tubes. Any ideas will be greatly appreciated!


----------



## MisterMudd

fjhuerta said:


> I was wondering if anyone has noise issues with this amp. I just got mine and it has this noise. It's not  a 60 Hz hum, it's like surface noise on vinyl. It's very noticeable. It goes out whenever I take out the tubes. Any ideas will be greatly appreciated!



Had mine 8 months now, and though the stock tubes were good I replaced them quickly. Try some other inexpensive tubes before sending the amp back to replace or refund. When it works, it works very well and sounds great. Got my replacement tubes on eBay.


----------



## fjhuerta

mistermudd said:


> Had mine 8 months now, and though the stock tubes were good I replaced them quickly. Try some other inexpensive tubes before sending the amp back to replace or refund. When it works, it works very well and sounds great. Got my replacement tubes on eBay.


 
 I hope it's the tubes, because this amp sounds as good as everyone else said it did. It's probably better than my old X-Can V2, much to my surprise. The noise is pretty noticeable. I'll have to hunt those tubes down, I haven't found them in the usual places.


----------



## edulov

Two most frequent reasons are:
 1) Amp's PSU. Try to connect via good surge protector or UPS.
 2) Audio cables, especially if amp is located near other electric devices with high energy consumption. I had this issue until I connected amp to DAC using HQ shielded audio cable. Prices for good cables actually start from 15 presidents, just look for oxygen free shielded male-to-male stereo 1/8" TRS (3.5 mm jack). Strangely, the best from cheap ones are labeled as Mic(rophone) cables while placing audio label triples the price. Huh-huh...
  
 +3) Much rare. Try to hear music connecting DAC to laptop running on batteries.Not all desktop and AIO PSU's are good actually.
  
 Keep us posted what you will discover.


----------



## TheBIGKill1998

fjhuerta said:


> I hope it's the tubes, because this amp sounds as good as everyone else said it did. It's probably better than my old X-Can V2, much to my surprise. The noise is pretty noticeable. I'll have to hunt those tubes down, I haven't found them in the usual places.


 
 My recommendation would be to upgrade the tubes first of all. You will find em relatively easy on ebay.
 2nd you should take care of not using cheap cables. I also had noise problems with my amp in the beginning, but after i upgraded my cables to some higher quality ones from cordial, that problem was gone. 
  
 And if you think the amp sounds good so far, then i really recommend to upgrade the opamp chips. 
 After an upgrade this amp sounds even better IMHO. 
 i know this has nothing to do with your noise problem, but its just some idea for you if you want to modify this amp a bit.


----------



## fjhuerta

thebigkill1998 said:


> My recommendation would be to upgrade the tubes first of all. You will find em relatively easy on ebay.
> 2nd you should take care of not using cheap cables. I also had noise problems with my amp in the beginning, but after i upgraded my cables to some higher quality ones from cordial, that problem was gone.
> 
> And if you think the amp sounds good so far, then i really recommend to upgrade the opamp chips.
> ...


 
  
 Strangely enough, I ran an RMAA sweep yesterday, and got a very low noise floor of -96.9 dB, or so. I don't know what happened, but today the amp is as noiseless as a SS amp.
  
 It still sings. I can't believe the price. I like it more than my X-Can V2.
  
 RMAA shows it has somewhat of a roll-off in the upper and lower end. -2 dB or so at 30 KHz, IIRC. I wonder if that's the reason why it's so sweet.  I can post the graphs later, f anyone is interested.
  
 I'll definitely upgrade the tubes and op-amps. Which would you recommend? Where could I get them?


----------



## TheBIGKill1998

fjhuerta said:


> Strangely enough, I ran an RMAA sweep yesterday, and got a very low noise floor of -96.9 dB, or so. I don't know what happened, but today the amp is as noiseless as a SS amp.
> 
> It still sings. I can't believe the price. I like it more than my X-Can V2.
> 
> ...


 
 oh, if the noise was only temporary it could have also been the burn in of the tubes! 
  
 and yeah... it could be the roll-off. i may not be an audio tech expert, but this sounds plausible. 
 which also might play a role it its sound could be the harmonic distortion. Do you have the chance to measure it? 
 would be interesting to know that.
 and yeah, i would be very interested in the graph! 
  
 for the tube and op amp rolling:
 i am currently using russian 6J9P tubes and LM4562NA opamps (since they are almost a perfect match electronically) and im quite happy with my setup.
  
 Both components are available mostly on ebay. And there should be plenty of those russian tubes for a low price. I got 10 of them for 20 euros (shipping included). 
  
  
 P.S.: if anyone has experience with other opamps, i would like to hear your opinions!


----------



## fjhuerta

There's something really weird about the amp. Somedays it's noisy, and somedays it isn't. I'll post the graphs later today.


----------



## edulov

fjhuerta said:


> There's something really weird about the amp. Somedays it's noisy, and somedays it isn't. I'll post the graphs later today.


 
 I had such behavior several times, but in my case, it was unrelated to amp:
 Amp <- Audio Cable <- DAC <-USB Cable <- Desktop PC <- Foobar2000 <- Windows 7
  
 So, guess what? Connecting to other USB port is not helping, but restarting Windows always help. So it could be DAC driver, USB drivers, Direct X, windows audio service.
 Next time it happens I'll try DirectX - ASIO since another DAC/AMP was playing OK.
  
 I mean that without knowing how your amp is connected there exist too many possibilities


----------



## fjhuerta

The noise is mainly in the upper bass area. I'll post a noise spectrum analysis later. The amp seems pretty dead silent in the mids and treble. It doesn't have anything to do with my computer. The noise profile is still there, even when not connected to anything!


----------



## fjhuerta

These are the measurements. I'm really disappointed. This amp measures like a chinese made, $50  "tube" amp should, unfortunately. It sounds great to my ears, though. I guess it's the distortion. FR is very rolled off, the amp is quite noisy, it has tons of distortion and crosstalk. Measurements are overlaid with my sound card's reference measurements.


----------



## MisterMudd

If it sounds good to your ears, should that not be the top priority?


----------



## edulov

fjhuerta said:


> The noise is mainly in the upper bass area. I'll post a noise spectrum analysis later. The amp seems pretty dead silent in the mids and treble. It doesn't have anything to do with my computer. The noise profile is still there, even when not connected to anything!


 
 Mine problem always were mids both with stock and rolled op amps BTW. Permanent noise means 10% PSU and 90% cables and fitting


----------



## diivve

Can anyone make a comparison video stock tube and different tube? Highly appreciated.


----------



## fjhuerta

edulov said:


> Mine problem always were mids both with stock and rolled op amps BTW. Permanent noise means 10% PSU and 90% cables and fitting


 
 In this case, I have to wonder if the problem is the circuit itself, and the SMD components. I mean, how nice can this sound with sub-standard components, even considering a nice topology?

 Having said that, I was really curious and measured my X-Can V2 against this.

 Guess what. Other than a flatter FR (which, I think, came to be because of the Rock Grotto upgrades), this unit is better performing everywhere else. Not kidding.


----------



## dr3wd4wg

I love this little amp, with LM4562s and Mullards it sounds great. Only issue is the volume pot, at lower volumes there is a channel imbalance.


----------



## edulov

Running through several tests just proved the well-known thing. A LOT depends on pre-amp or DAC. Made test with several tubes and different inputs. Mids, treble, high treble - no roll offs when no roll-off in input signal. Slight, but noticeable difference below 100Hz with different tubes. You need really good ears and headphones, but it is not an imagination. Above 100Hz no FR difference, just different noise specs and dynamic range.
 BUT! My roll off "character" at lows look similar to yours, but not exactly the same in magnitudes. It goes slower than yours between 30 and 100Hz.
 Since most people cannot hear the difference lesser that 0.5dB, there is no problem above 37Hz for me.


----------



## fjhuerta

I'm thinking about getting a much stiffer power supply: 4A at 6VDC. Then, roll tubes and op amps. Can't hurt.


----------



## TheBIGKill1998

fjhuerta said:


> I'm thinking about getting a much stiffer power supply: 4A at 6VDC. Then, roll tubes and op amps. Can't hurt.


 
 Would you actually recommend getting a stiffer PSU? 
  
 P.S.: interesting graphs you got there


----------



## edulov

Won't put these graphs here, but 60Hz noise is a problem with stock PSU. Even if it is below an audible level (unless you plan to kill your ear drums). But the price of the really good one is above 100$$, it is an overkill for the cheap amp. But I'll be looking for the universal model, 3-12V, up to 3-3.5A with switchable polarity and set of plugs.
 Any ideas, BTW?


----------



## vapman

Can anyone post a shot of the pcb? thanks


----------



## TheBIGKill1998

vapman said:


> Can anyone post a shot of the pcb? thanks


 
 in this video: https://youtu.be/9RhD-NO0n-4?t=143
  
 you can see some close up shots of the PCB.


----------



## vapman

thebigkill1998 said:


> in this video: https://youtu.be/9RhD-NO0n-4?t=143
> 
> you can see some close up shots of the PCB.


 
 Thanks a bunch. I guess the google ones were right then =)
  
 i will post when i have mine with linear PSU, swapped opamps (probably burson v5i), russian tubes


----------



## Brian Coffey

vapman said:


> Thanks a bunch. I guess the google ones were right then =)
> 
> i will post when i have mine with linear PSU, swapped opamps (probably burson v5i), russian tubes


 
 Interested to hear your thoughts with the Bursons in it


----------



## edulov

Be carefull with Burr-Brown's. ALMOST EVERYWHERE, old ones and new ones are classified as dark sounding ones with overall emphasis in lows and lower mids resembling frequency shift.


----------



## Andrew Ellicott

I just got one for my birthday.  Haven't had much time to play with it yet, but, at least for the time being I will be pairing this with a pair of JVC ha-sz2000's.  Anyhow I noticed with the stock tubes, 1 glows brighter orange than the other.  I switched the tube positions to make sure it was an issue with the tubes.  Is this normal, or something I should contact the MFG about?
  
 Also is there a burn in period or anything I should be aware of to help my listening experience, besides swap tubes.  I'm COMEPLETELY new to all of this, besides a bit of reading.
  
 Thanks!


----------



## edulov

If you have recording device capable to show detailed level (or soundcard with line input and more or less advanced free rec SW, connect amp's line out to rec device line in and reproduce the same intensity signal for L/R.
 If recording levels differ more then 0.1-0.2dB you have a different wear of valves, so different colour mean different temperatures of the elements inside the lamp. If difference if constant, but small, you can change L/R balance of the playback device while recording to match recording levels. For the differences higher than 0.5dB better search for a replacement. If you plan to do tube rolling, better buy 3-4 units to select matching pair or pay more, ordering from reliable source which already guarantees pair matching via special testing device.


----------



## fjer

I have just ordered a NS-08E for tube rolling fun, but also a NS-01E (the small one with a single tube) to use at work.
 With its 5x5 cm it can easily stand on top of an ODAC, and with a minijack jumper cable it will make a very compact solution. And hopefully a more pleasant listening experience than O2+ODAC, which I have found a bit too fatiguing with Ultrasone PRO900.
  
 It will be interesting to compare NS-08E and NS-01E against each other.
 Nobsound claims that NS-01E is their best headamp, but it might just be a marketing trick or because its stock tube is better than the ones on NS-08E.
  
 Changing the tube on NS-01E is probably also a good idea, although it will require some soldering. Does anybody know which one it is? An ECC70/6021 perhaps?
  
*EDIT:*
 How long does it generally take for these E180F/6688/6Ж9П tubes to burn-in enough to reveal their true sound signature when paired with the NS-08E?
 I went a bit overboard and ordered 7 different sets of NOS tubes (Tesla, Philips, Dario Miniwatt, 60's Valvo, 80's Mullard, 70's 6Ж9П-Е and 80's 6Ж9П-Е). I am eager to try them out, but in order to make a fair comparison I should probably start out by doing some kind of systematic burn-in for all of them.
 I am thinking about 24 hours of music at a reasonable volume level for each tube pair. Would that be enough to give them a fair amount of burn-in?


----------



## TheBIGKill1998

fjer said:


> I have just ordered a NS-08E for tube rolling fun, but also a NS-01E (the small one with a single tube) to use at work.
> With its 5x5 cm it can easily stand on top of an ODAC, and with a minijack jumper cable it will make a very compact solution. And hopefully a more pleasant listening experience than O2+ODAC, which I have found a bit too fatiguing with Ultrasone PRO900.
> 
> It will be interesting to compare NS-08E and NS-01E against each other.
> ...




Well, the question is whether burn in actually is a thing or not.... but i dont want to start this discussion.
if you want to burn them in i think that 24 hours of music would be fine i guess.


----------



## TheBIGKill1998

How well do you guys think will this amp pair with a beyerdynamic dt 770 pro 80 ohm?


----------



## erich6

fjer said:


> How long does it generally take for these E180F/6688/6Ж9П tubes to burn-in enough to reveal their true sound signature when paired with the NS-08E?
> I went a bit overboard and ordered 7 different sets of NOS tubes (Tesla, Philips, Dario Miniwatt, 60's Valvo, 80's Mullard, 70's 6Ж9П-Е and 80's 6Ж9П-Е). I am eager to try them out, but in order to make a fair comparison I should probably start out by doing some kind of systematic burn-in for all of them.
> I am thinking about 24 hours of music at a reasonable volume level for each tube pair. Would that be enough to give them a fair amount of burn-in?



I've tried a few different types of tubes and I haven't noticed much of a burn-in effect with any of them...certainly nothing like what I've experienced with some headphones.


----------



## fjer (May 1, 2017)

Thanks, I also haven't noticed much change with the tubes I have tried so far. I thought that it would be different with NOS tubes after several decades of storage.

I am quite impressed by the Soviet tubes - mine are gold pin 6Ж9П-Е's from 07/86. They were by far the cheapest ones of all the tubes I had been looking at, so I didn't expect much from them.
They sound very good, and are completely dead in regards to microphonics. I can bang a chopstick against them without getting any feedback at all in the headphones. That does not hold true for the Philips, Mullard (military) and Tesla (military) tubes that I have put up to the same test, which all give a slight ring. And of course the sub-par Chinese stock tubes that ring even when tapping the amplifier enclosure.

Regarding the NS-01E; it's just as powerful as NS-08E, but it doesn't handle low-end frequencies very well IMO. However, the tube might be to blame. It seems to be a Chinese 6021 of the same brand as on NS-08E. It's dead silent when doing the chopstick test, though.
It would be interesting to replace it with a proper NOS tube to see if that improves its sound. Maybe also put in a couple of DIP8 sockets to allow for easy opamp rolling.
NS-01E also has two NE5532's and uses exactly the same power supply as NS-08E. My guess is that they just copied and miniaturized NS-08E's layout and replaced the two tubes with the smallest/cheapest dual-triode tube they could fit for the purpose, so that it could still be marketed as a "tube amplifier".

In other words, don't feel bad if you considered buying NS-01E but ended up with a NS-08E.


----------



## fjhuerta

So, here are my impressions after doing some things to the amp.

1) Stiffer power supply. I bought a 4A 6V regulated power supply.
No changes whatsoever. The little wall wart included isn't a real factor in how this amp performs.

2) A 6V battery.
Lower noise floor. But not by much. Performance is pretty much the same.

Here are my findings.

1) The amp hates low impedance headphones with a passion.
2) The amp works better than an X-Can V2 with higher impedance headphones, except for some noise I can't get rid of.
3) The amp is far, far more powerful than most of the Fiio products you can get for twice the price.



Theses graphs show how the NobSound behaves when not loaded with any headphones (blue trace) vs. with a battery supply and the upgraded power supply (green and white traces) with a set of Fiio EX-1 headphones connected.




 
The amp really suffers with the EX-1s!



 
Likewise. Worst performance comes when battery powered and loaded with the Fiios.



 

Quite a noisy amp. When battery powered, it's a bit quieter.



 

Intermodulation distortion, again, is worse when battery powered.

Looks terrible. But...


----------



## fjhuerta

Things change for the better with a full size can. I connected my AKG 712 Pros to the NobSound and Fiio Kunlun. Here's what I found.

The Fiio Kunlun is flatter, but the NobSound doesn't exhibit anymore the terrible frequency deviations it had with the Fiio EX-1 in ear. I guess the NobSound has a greater output impedance than expected.



 



 
Once again, the Fiio is better than the Nobsound. There's less noise below 3 Khz. There's a tiny bit less of noise when the NobSound is battery powered, but nothing special. 



 


Having said that, the Kunlun has tremendously higher THD numbers, by a factor of more than 10. So, although the Kunlun is a more accurate amp, it simply can't power the AKG's as well as the NobSound. Strange, because I thought 300mW would be more than enough for the AKGs. I was wrong.

I'd definitely use the NobSound instead of the Fiio Kunlun for the AKGs.


----------



## fjhuerta

Things change for the better with a full size can. I connected my AKG 712 Pros to the NobSound and Fiio Kunlun. Here's what I found.

The Fiio Kunlun is flatter, but the NobSound doesn't exhibit anymore the terrible frequency deviations it had with the Fiio EX-1 in ear. I guess the NobSound has a greater output impedance than expected.

 

 
Once again, the Fiio is better than the Nobsound. There's less noise below 3 Khz. There's a tiny bit less of noise when the NobSound is battery powered, but nothing special. 

 


Having said that, the Kunlun has tremendously higher THD numbers, by a factor of more than 10. So, although the Kunlun is a more accurate amp, it simply can't power the AKG's as well as the NobSound. Strange, because I thought 300mW would be more than enough for the AKGs. I was wrong.

I'd definitely use the NobSound instead of the Fiio Kunlun for the AKGs.


----------



## fjhuerta

And here's the NobSound (battery and Wall-Wart powered) vs the X-Can V2.

The X-Can V2 is a similar design, after all - a hybrid with no tube preamp, but rather a tube buffer using a 6922 tube. It cost $299 IIRC in 2000. The Nobsound cost me $35 on eBay a couple of weeks ago. So, let's see.



 

YIKES. This is evil. The X-Can, with the loaded AKG, looks like a smiley face EQ next to the flatness of the Nobsound.  Strangely enough, I'd have expected at least a similar curve out of both of them, because of impedance interaction between headphone and amp. The X-Can is simply all over the place. "Sounds exciting" would be my first guess as to how the X-Can behaves with the AKG.



 

Once again, there's too much noise on the lower end of the NobSound, but the X-Can has more noise in the most sensible range of our hearing, and it has a weird 5 KHz bump that is noticeable on other graphs. The NobSound is actually quieter.

Note: The NobSound was pretty noisy with the Fiio EX-1. The AKG 712Pros don't make that noise so evident.



 

The THD sweep gives the nod to the X-Can. It has lower distortion levels than the NobSound. The NobSound while battery powered has lower distortion levels than when powered wiht a wall wart.



 

The X-Can has higher THD than the NobSound, while battery or wall wart powered.



 

The NobSound has better dynamics all around than the X-Can.


----------



## fjhuerta (May 14, 2017)

So, there you have it. For $35, you can have a tube buffered SS amp that can actually power your big headphones with ease. It's better (IMHO) than a $299 circa 2000 amp, and it can power hungry headphones better than $100 Fiio amps.

It's quite a bargain, provided that you don't use it with low impedance or sensitive cans. It loves Sennheiser HD600s and AKG 712 Pros. It's a bit noisy in the low end, and you'll probably notice it (then again, maybe not). But it's pretty flat, it's distortion is kept on check, and it has tons and tons of power.

I'd definitely use it with a sealed battery for best performance. And it looks cool. I'll take a pic later, the battery is the same size as the amp!


----------



## TheBIGKill1998 (May 15, 2017)

Good job dude!

very interesting results you got there!

Im using this amp currently with my new beyerdynamics dt 770 pro 80 Ohm.
I think that also is a nice combo.

i wish i had the equipment to measure all that kind of stuff.
because i would really love to see how my mods on the nobsound perform.


----------



## daySpring

I've been using this little beast for little over a month now to drive T1.2, HD650, HE400i, K702 etc. Gotta say, after getting a $15 6V3A (dialed in) wall wart and getting rid of the annoying power noise that used to creep in after the amp has been left on for more than an hour, this is my all day driver for high impedance cans. Magni2 and M-stage HPA2 are rarely seeing any play time.

The stock 6j9p tubes are very 60s 'tube' sounding, warm but lots of distortion (read: not detailed) and tends to emphasize the fundamental tone and sound sort of overdriven. Rolling in a couple of NOS Philips Miniwatt SQs really cleaned up the sound.

The volume knob tough, seems to have no effective gain past the 2 o'clock position. So, Even though it is quite powerful, not as much as I first thought it was since I couldn't get past 9 o'clock on most cans with digital volume set at 100% in Foobar2k. On the bright side, I don't own a HE6, so not really worried about drive such cans.

Looking for recommendations for tube rolling for my old HE400 with Audeze vegan pads. Just like with the Magni2, this NS-08E gets quite sibilant at a little higher than regular listening volume. Need to tame that and pump a bit more tight sub bass that is sort of rolled off with the vegan pads.


----------



## Balder

Hi guys!

Thinking of buying one 08, but i use, and love, my Shure SRH940 - with an imp of just 42 ohms! Those of you who followed the somewhat "infected" debate when they came on the market in 2011, may remember that some claimed they were "Godlike", others just discarded them as booring, bass fatigued and to bright... bla bla... I bought them back in 2013, and they suit me fine. But they can be to analythical at times, and despite the low imp - they are "picky" on amps. So i was thinking maybe a "tube-hybrid" can make them a little more rock'nroll, live and smoothen them? I have read the whole thread and if i have got it right = 08 likes a heavy, imp and load? So are they right for Shure940? Or should i look at something like smsl sap vi, about the same price for me (ie SS OP-Amp "based")? I love to experiment, so maybe there is some tweaks that will make the combo Nob 08 + Shure to work? Anybody tried those HP on the 08?

Going to place a order for "an" HP-Amp at the end of July, in that price range up to $50.... so is it a bad idea to get the Nob 08, in my case? (no plans for a HP upgrade anytime soon).

Cheers/T.


----------



## TheBIGKill1998

Balder said:


> Hi guys!
> 
> Thinking of buying one 08, but i use, and love, my Shure SRH940 - with an imp of just 42 ohms! Those of you who followed the somewhat "infected" debate when they came on the market in 2011, may remember that some claimed they were "Godlike", others just discarded them as booring, bass fatigued and to bright... bla bla... I bought them back in 2013, and they suit me fine. But they can be to analythical at times, and despite the low imp - they are "picky" on amps. So i was thinking maybe a "tube-hybrid" can make them a little more rock'nroll, live and smoothen them? I have read the whole thread and if i have got it right = 08 likes a heavy, imp and load? So are they right for Shure940? Or should i look at something like smsl sap vi, about the same price for me (ie SS OP-Amp "based")? I love to experiment, so maybe there is some tweaks that will make the combo Nob 08 + Shure to work? Anybody tried those HP on the 08?
> 
> ...




Im using mine with my 80 Ohms Beyerdynamics DT 770s. Im totally happy with the combo. Im not sure how much the linearity and noise and such change between 42 and 80 Ohm... so i cant tell you very much about it. 
From my experience i can only say, that this amp, is totally recommendable.


----------



## TheBIGKill1998

After i had my volume (by accident) turned up completely, whilst my 80Ohm Beyerdynamics where plugged into this amp, i wonder if the max output power of this amp damaged my headphones.

Is it possible that the max output power of this amp (1100 mw on 32 ohm load, accodring to amazon) can damage 80Ohm Headphones?


----------



## Balder

Thank's for the reply "TheBIGKill1998"!

If you feed nearly a whooping 1 W into a headphone, that's probably designed to handle about 300mW, you can definitly "burn" them, especially if the amp is driven to a point of overload, then "clipping" occurs and the amp can in worst case scenario emit DC current to the phone, the coil in all dynamic phones/speakers(tweeters) can not handle DC(burnt a few "tweeters" my self in the "early" years of my HiFi hobby - but we all have to learn by our/(others) mistakes!). 1W can actually power a sensitive speaker to some degree... But, if they are "damaged", they would either "die"(burnt coil), or have a "crackling"(damaged membrane) sound - i am shure that you would hear that. So if they sound OK, you probably got away this time. If they are dead(and without warranty), replacing the driver units is not that hard/expensive to do your self - if you have some "DIY" skills. You may even "improve" their performance by getting "alternative/better" driver units. For advise on the "DIY" part i strongly recomend visiting the "diyAudio" forum - there are some very experienced people there that can "guide" you!

I think i will have a go at the Nob, the tweak potential alone is worth the money! If nothing else - it will keep me "entertained" for a long time, beeing retired with loads of time, lol!

Cheers!/T.


----------



## TheBIGKill1998

Balder said:


> Thank's for the reply "TheBIGKill1998"!
> 
> If you feed nearly a whooping 1 W into a headphone, that's probably designed to handle about 300mW, you can definitly "burn" them, especially if the amp is driven to a point of overload, then "clipping" occurs and the amp can in worst case scenario emit DC current to the phone, the coil in all dynamic phones/speakers(tweeters) can not handle DC(burnt a few "tweeters" my self in the "early" years of my HiFi hobby - but we all have to learn by our/(others) mistakes!). 1W can actually power a sensitive speaker to some degree... But, if they are "damaged", they would either "die"(burnt coil), or have a "crackling"(damaged membrane) sound - i am shure that you would hear that. So if they sound OK, you probably got away this time. If they are dead(and without warranty), replacing the driver units is not that hard/expensive to do your self - if you have some "DIY" skills. You may even "improve" their performance by getting "alternative/better" driver units. For advise on the "DIY" part i strongly recomend visiting the "diyAudio" forum - there are some very experienced people there that can "guide" you!
> 
> ...



Hello,

first of all, thank you for your answer on my question!

My headphones dont have any crackling noises from what i can hear so far.
They still (to me) sound quite good. 

and also, thank you for your DIY recommendation. If i should ever kill my headphones, i will take a look at the diy audio forum.


----------



## Balder

You are welcome!

By the way, reading on Amazon what people said after bying the Nob, and there was some 100+ comments. A few had have their, some times very expensive, HP's "killed" by the Nob? Reason being was that for some "unknown" reason the Nob had suddenly started emiting loud "hi pitch" noise, apperantly while playing? One guy had two HP's killed, one witch cost $200+!
But the wast majority of those who bought the Nob, and had HP's > 250 ohm's, was extremely pleased with it!

I am getting "cold feet". I have decided to go either OP-Amp "finished product": Douk "BlueBird 5.0" class A mini desktop HP-Amp(OP NE5534x2) = $50, Alternative: SMSL sAp8 = $60 (special offer!). Or go "easy-DIY" and buy: "soldered, finnished, tested-OK", board, discret class A "MOS-FET" + a transformer to feed it (AC 2x18V) = total ca $45, without casing. Witch falls within my budget (exept the sAp8 - need some serius "negotiation" with the wife for that, lol!). 

That since i don't really need the "huge" power output from the Nob, and the, rare, but serius "wierd" behaivour of the Nob? For "difficult" HP's - Nob have no competition in that price segment! But i think, in my case, 200 - 300mW, into 42 ohm - would suit my need's!

The "Douk BlueBird 5.0" i somewhat of a "wildcard", but you can "roll" the OP's, and tweak it in other ways, where as the SMSL is an "end" product - nothing that i can tweak(judging from pics of the inside!). Well - I am placing the order on "a" HP-Amp at the end of July, so who know's what other gadget's i'l find?

I am somewhat "obsessed" by getting maximum "bang/buck"!


Cheer's/T.


----------



## DavidK35

Well I have had this amp for 14months now, and I have the same opinion of it now as I did when I first got it.
This is the best amplifier bargain of all time. I run this thing everyday for an average of 5 hours a day & it performs faultlessly. Sound is so good it runs my main headamp a close 2nd.

Some notes:

1) I have 3 headphones all around 50-55 impedance, all work perfectly well (see profile).
    No issues whatsoever

2) I use the NOS 6688A tubes (recommended). 10,000 hrs rated & still going strong.
     Life of tubes is not an issue

3) I use this adaptor for the Sennheisers (cost less than $4). No issues.

 

4) It does make a loud thump when you turn it on. Have your headphones off & volume at zero
    and it will not be an issue

5) I use a regulated power supply, cost $15 fwiw.
    No issues.



6) Amp runs very warm not hot.
    Heat is not an issue.

I say again this is the best bargain out there IMO.


----------



## MisterMudd

DavidK35 said:


> Well I have had this amp for 14months now, and I have the same opinion of it now as I did when I first got it.
> This is the best amplifier bargain of all time. I run this thing everyday for an average of 5 hours a day & it performs faultlessly. Sound is so good it runs my main headamp a close 2nd.
> 
> Some notes:
> ...



Everything you say nails it! The little amp opens up every headphone I plug in, and it's awesome.


----------



## TheBIGKill1998

MisterMudd said:


> Everything you say nails it! The little amp opens up every headphone I plug in, and it's awesome.


Yep, this amp is pretty amazing!

Also, i got a question for everybody here. 
Is it possible that the loud popping noise, which occurs when you turn the amp on, can damage plugged in Headphones?


----------



## Slipmyster

Hi everyone. 
New hear. I've had my NS-08e for about 4 month now. I settled on the nobsound after reading a lot of good things about it on this forum and I'm glad I did.
At the moment I'm useing it with my jvc ha-rx900 headphones and it sounds really nice. I changed the tubes for a pair of Russian tubes that stoped the ringing and improved the sound a lot. 
I also put a couple of heatsinks on the op amps to help take some of the heat. 
It's a nice little amp for sure.


----------



## erich6

TheBIGKill1998 said:


> Yep, this amp is pretty amazing!
> 
> Also, i got a question for everybody here.
> Is it possible that the loud popping noise, which occurs when you turn the amp on, can damage plugged in Headphones?



I'm not sure but I always err on the side of caution and only plug headphones in a few seconds AFTER I've turned on the amp.


----------



## MisterMudd

erich6 said:


> I'm not sure but I always err on the side of caution and only plug headphones in a few seconds AFTER I've turned on the amp.


I concur, even though from all I have read it  seems to be okay if it is a low thump. If it is a loud thump or pop it is probably not good. I use a short headphone plug extension that stays connected to my amp, to save wear and tear on the amp plug.


----------



## TheBIGKill1998

MisterMudd said:


> I concur, even though from all I have read it  seems to be okay if it is a low thump. If it is a loud thump or pop it is probably not good. I use a short headphone plug extension that stays connected to my amp, to save wear and tear on the amp plug.



ahh alright, i basically do the same. i just wanted to get sure whether it was needed or not.

but i think i just gonne leave as it is then.



Also, i get quite some interference when my smartphone is in the same room as my amp.... is there a way i could kinda shield my amp?


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## Slipmyster (Aug 29, 2017)

Hi again.
Just wanted to show the heatsinks I put in my ns-08e
And my home made tube dampers made from an old leather belt.


----------



## erich6

Nice, thanks for sharing those pictures!


----------



## hjribeiro

I have a pair of HD650's and a chord mojo. I was looking for a cheap for a cheap tube amp just to see if I like the tube sound and to try out the tube rolling hobby 

This morning ( 8 hours ago ) I have accidentally discovered this amp. First place i came for reviews is here and when I find it has 13 pages(!!) on the forum I didn't hesitate! 13 pages for a 39£ tube amp? I need to have it.  I bought it on amazon uk and it arrives tomorrow.

Throughout my work day I was able to read most of the replies here and I feel I made a great decision buying it,

I will post an update of how it sounds, with the stock tubes, and how dfoes it pair with my mojo.

And now a question: Does anyone know where to buy tubes for this around Birmingham UK? I prefer to go to a store and help local retail than just buy random tubes on ebay.


----------



## Slipmyster

hjribeiro said:


> I have a pair of HD650's and a chord mojo. I was looking for a cheap for a cheap tube amp just to see if I like the tube sound and to try out the tube rolling hobby
> 
> This morning ( 8 hours ago ) I have accidentally discovered this amp. First place i came for reviews is here and when I find it has 13 pages(!!) on the forum I didn't hesitate! 13 pages for a 39£ tube amp? I need to have it.  I bought it on amazon uk and it arrives tomorrow.
> 
> ...



Hope you like it. Let us know what you think.
Sorry can't help with the tubes here in the uk I bought some Russian tubes on ebay and they are a big improvement on the stock tubes.
The Chinese tubes that come with the amp are very microphonic.


----------



## hjribeiro

Slipmyster said:


> Hope you like it. Let us know what you think.
> Sorry can't help with the tubes here in the uk I bought some Russian tubes on ebay and they are a big improvement on the stock tubes.
> The Chinese tubes that come with the amp are very microphonic.



I have not tried it much, but what I can tell so far is that it brings me not much coloration, the way I am using it.

If i use it directly from my laptop to power my HD650's, it powers them. They get loud. But still the bass is not there, very recessed - but that could be the source.

If I use it after my chord mojo, I "think" I can tell a difference. Very slightly - but could be placebo. Perhaps the tubes need some burn-in, or I need to swap them. I'll give it another go later this week and let it on for a couple of hours more. If I can't tell a significant difference I might get some new tubes.

It looks cool though


----------



## Slipmyster

hjribeiro said:


> I have not tried it much, but what I can tell so far is that it brings me not much coloration, the way I am using it.
> 
> If i use it directly from my laptop to power my HD650's, it powers them. They get loud. But still the bass is not there, very recessed - but that could be the source.
> 
> ...



What you are describing sounds about right for the stock tubes. 
Bright with not a lot of bass and not a lot going on with the soundstage.
I wouldn't judge it with those Chinese tubes they are not much cop and do the amp no justice.
Roll the tubes as soon as possible. You don't need to spend a fortune on them to get a big improvement.


----------



## hjribeiro

Slipmyster said:


> What you are describing sounds about right for the stock tubes.
> Bright with not a lot of bass and not a lot going on with the soundstage.
> I wouldn't judge it with those Chinese tubes they are not much cop and do the amp no justice.
> Roll the tubes as soon as possible. You don't need to spend a fortune on them to get a big improvement.



You just gave me the hope in it i needed to order a pair of tubes.

Is there any tubes you recommend? There are plenty suggestions on this thread - thinking of buying the ones that I could get quicker


----------



## Slipmyster

hjribeiro said:


> You just gave me the hope in it i needed to order a pair of tubes.
> 
> Is there any tubes you recommend? There are plenty suggestions on this thread - thinking of buying the ones that I could get quicker



Sorry but I'm only just starting on the tube rolling path. I bought the Russian tubes as I didn't want to spend too much incase I couldn't tell the difference. They have convinced me there is more to come in sound quality and they are solid I can tap my amp and there is no microphones at all. 
They have made this little amp sing.


----------



## Tom Steed

i use E180F's in mine and it sounds great(to me) ebay is a good source for these valves. http://www.ebay.co.uk/itm/Mullard-E...epid=0&hash=item4862795185:g:CTMAAOxy4YdTQtGw


----------



## hjribeiro

Tom Steed said:


> i use E180F's in mine and it sounds great(to me) ebay is a good source for these valves. http://www.ebay.co.uk/itm/Mullard-E...epid=0&hash=item4862795185:g:CTMAAOxy4YdTQtGw


Isn't it better to buy matched pairs?


----------



## Tom Steed

This was just an example, the chances are if you bought 2 they'd be NOS from the same batch. A matched pair will be more expensive.


----------



## hjribeiro

Tom Steed said:


> This was just an example, the chances are if you bought 2 they'd be NOS from the same batch. A matched pair will be more expensive.


They're on their way


----------



## Slipmyster

hjribeiro said:


> Isn't it better to buy matched pairs?



I bought two matched pair. Tom Steed is right they will cost a bit more for the matched tubes bit how much will depend on the seller


----------



## erich6

Refer to earlier posts in this thread for detailed description of tube sound differences. Amperex NOS will provide better bass.


----------



## dhaninugraha

Just pulled the trigger on this amp. Wonder how the rMBP > Hifiman HM-101 > NS08E > HD25 combo would sound.


----------



## sup27606

I got Mullard CV3998 E180F 6688 Vacuum Tubes matched pair from eBay last year. Costed me $25 for the pair. It seems, the price has gone down as of now. Matched pairs of same specs are available now for $18 shipped at eBay.

These tubes seem to have good bass without being boomy, and great soundstage both in width and breadth. The soundstage with Sennheiser 6XX is definitely bigger than what I get from Schiit Jotunheim. Also, the clarity is not any less either. I really like to hear live recordings through the Nobsound, because the bigger soundstage gives better feeling of the auditorium. I am feeding the amp from Mimby.

Does anyone know, how to solve the pops and cracks that occasionally occurs in the sound? Are they the tubes or the power supply? I notice, they always happen in the left earpiece.


----------



## Slipmyster

sup27606 said:


> I got Mullard CV3998 E180F 6688 Vacuum Tubes matched pair from eBay last year. Costed me $25 for the pair. It seems, the price has gone down as of now. Matched pairs of same specs are available now for $18 shipped at eBay.
> 
> These tubes seem to have good bass without being boomy, and great soundstage both in width and breadth. The soundstage with Sennheiser 6XX is definitely bigger than what I get from Schiit Jotunheim. Also, the clarity is not any less either. I really like to hear live recordings through the Nobsound, because the bigger soundstage gives better feeling of the auditorium. I am feeding the amp from Mimby.
> 
> Does anyone know, how to solve the pops and cracks that occasionally occurs in the sound? Are they the tubes or the power supply? I notice, they always happen in the left earpiece.



Do you have a different pair of tubes to try in place of the mullard's. 
Have you try'd re seating the tubes to make sure you have a clean connection.
May be someone with more experience may be able to give more advice. Hope you get it sorted.


----------



## edulov

About noise and cracks there is an easier solution. Swap the tubes and keep using them for a while till I'll get this effect again. Channel will change - one tube has more problems and you need to find a replacement. Otherwise the problem is outside. So, try to connect Nob' to other music gear and keep hearing. If the sound is clear, then your initial PC is guilty, still getting weird sounds - Nob's PSU (Most probably).
In the case of PC I've seen 3 most frequent problem origins: computer PSU, bad amp's input jack connection of audio cable (should not be a case if cable is not moving at the moment when cracks appear). And the third - problems with USB port if you have an usb DAC (the case of internal of internal sound card I shall mention at the end). Here you have different options to check. The best one - use Nob' for a while without computer just to ensure that problems have a PC as an origin.
If it is a case, most parasite sounds I was getting when PC was heavily loaded while playing audio. Normally, assigning quite bigger audio buffer size in player solves the problem. But if you are shure that cracks were appearing even at nearly idle PC state, the problem is in USB port, but once again, it could be caused by computer PSU. Here you need to try another USB port to confirm if it is a motherboard problem (still not 100%) or computer PSU. Laptop owners have lesser options, but as if in the case of the internal sound card, try to install the other, used one. Even a cheap one.

May be you will forge another sequence of checks depending on your computer/audio gear setup. Sadly, if the tube swap does not give an answer it will take time checking options unless problems appear for heavily loaded PC only. Just for interest, tell us later what happend in your case.

BTW, don't laugh at bad jack connection, especially if the Nob position is not permanent and cables somehow could be touched/displaced occasionally.


----------



## Tom Steed

Slipmyster said:


> I bought two matched pair. Tom Steed is right they will cost a bit more for the matched tubes bit how much will depend on the seller


I also put a pair of these in, JRC 4558D. These are inexpensive high quality op amps and they sound great.


----------



## Slipmyster

Tom Steed said:


> I also put a pair of these in, JRC 4558D. These are inexpensive high quality op amps and they sound great.



Thanks for the information I've bin thinking of trying to roll the op amp chips but wasn't sure witch ones would work and didn't want to risk doing any damage. 
Thanks again I'll get a pair. Do op amps need to be matched ?


----------



## Tom Steed

no, they should all be manufactured to the same spec. I would buy 2 from the same supplier though. copy this item number into fleabay, they're the pair i got: 182581579004


----------



## Slipmyster

B


Tom Steed said:


> no, they should all be manufactured to the same spec. I would buy 2 from the same supplier though. copy this item number into fleabay, they're the pair i got: 182581579004





Tom Steed said:


> no, they should all be manufactured to the same spec. I would buy 2 from the same supplier though. copy this item number into fleabay, they're the pair i got: 182581579004



Brilliant. Thank you very much


----------



## edulov

Matched not necesarilly means the same fabric or lot. Several electric parameters measured by special test unit must be very close to avoid bias for L/R. Since it takes time to proceed and make groups (some electrical devices need more than 2 equal tubes), usually they cost more, or the same seller makes quality batches.
You can discover the final result recording the amp's output with the same L/R setting at sound origin. Or using RMAA "live", it has this special option to adjust recording inputs.


----------



## sup27606 (Oct 10, 2017)

edulov said:


> About noise and cracks there is an easier solution. Swap the tubes and keep using them for a while till I'll get this effect again. Channel will change - one tube has more problems and you need to find a replacement. Otherwise the problem is outside. So, try to connect Nob' to other music gear and keep hearing. If the sound is clear, then your initial PC is guilty, still getting weird sounds - Nob's PSU (Most probably).
> In the case of PC I've seen 3 most frequent problem origins: computer PSU, bad amp's input jack connection of audio cable (should not be a case if cable is not moving at the moment when cracks appear). And the third - problems with USB port if you have an usb DAC (the case of internal of internal sound card I shall mention at the end). Here you have different options to check. The best one - use Nob' for a while without computer just to ensure that problems have a PC as an origin.
> If it is a case, most parasite sounds I was getting when PC was heavily loaded while playing audio. Normally, assigning quite bigger audio buffer size in player solves the problem. But if you are shure that cracks were appearing even at nearly idle PC state, the problem is in USB port, but once again, it could be caused by computer PSU. Here you need to try another USB port to confirm if it is a motherboard problem (still not 100%) or computer PSU. Laptop owners have lesser options, but as if in the case of the internal sound card, try to install the other, used one. Even a cheap one.
> 
> ...




Thanks for all the suggestions. Good to remember if such problems happen in future. I don't know why, but the cracking sounds went away the next day. I have been listening for several days, and it hasn't come back. May be the jacks, that would be my guess.

Based on your impression couple of pages back, I am trying to find a pair of Amperex JEP 6688 tubes (I use the Mullards currently) online, but seems hard to find for cheap. How much should I expect to pay for a pair from the same batch (not necessarily matched)?

I am almost exclusively using the Sennheiser 6XX with the Nobsound. My personal view is, the Sennheiser synergizes very well with the Nobsound, fed from a Mimby. The other headphone I tried, Audeze EL-8 didn't sound so well, which explains the frequency curves for low impedance headphones. The soundstage from the Sennheiser/Nobsound combo is superb! and I came to this conclusion after hours of listening with a variety of music. To my ears, it surpasses the soundstage from the Schiit Jotunheim even in the balanced configuration. With the Nobsound, the sound has a beautiful smoothness to it without sacrificing details. Due to the smoothness, the micro-details are in fact more audible, and music can be enjoyed at low volume without losing impact. The sound almost feels magical, with subtle positional cues and a voluminous soundstage. None of the sound overpowers others or seem out of place. Vocals ARE amazing. I just feel, a slight sparkle (and I mean very little) in the treble could help in some of the tracks, for instance with the string instruments. Thats why, I am looking at the Amperex JEP.


----------



## edulov

Reasonable Ohm discussions is difficult to led w/o measuring, but to my hearing greater Ohm - sounds better. At least 32Ohm. Lower ones produces lifeless effect to me and less bass control.


----------



## sup27606

Slipmyster said:


> Do you have a different pair of tubes to try in place of the mullard's.
> Have you try'd re seating the tubes to make sure you have a clean connection.
> May be someone with more experience may be able to give more advice. Hope you get it sorted.



Thanks. luckily, the noise has disappeared and not come back again.


----------



## dhaninugraha

According to my country's PO, my NS08E package has arrived and on the way to the PO closest to me. Hopefully I'll have the package by this weekend. Can't wait to try it!


----------



## sup27606

After reading the recommendations in this thread, I was looking for Amperex-JEP 6688 online, but seems hard to find a pair of tubes that says JEP. There are plenty of matched pairs with the name Amperex PQ. Is there a difference between PQ and JEP?


----------



## edulov

As far as I recall JEP - USA made, PQ - Holland made. So their real electric specs could be slightly different. JAN - is a military grade long life version.


----------



## sup27606 (Oct 17, 2017)

edulov said:


> As far as I recall JEP - USA made, PQ - Holland made. So their real electric specs could be slightly different. JAN - is a military grade long life version.



Thanks very much. I see several JANs for sale. I was wondering if anyone compared the sound characteristics of the JAN vs JEP.

Edit: OK, got my answer from your January post. The JEP version has tighter bass, while the A version has a smoother sound. JEP is it for me then.


----------



## dhaninugraha

Mine has finally arrived!

_Well-packaged:_
_


_


_Against the Note 5 for scale:_
_

_


_Tubes on, ready to rock:_
_

_


_Them glowing tubes:_
_

_


----------



## Slipmyster

Nice.
Hope you like it. Don't judge it to much with the stock tubes they tend to ring like a bell every time you look at them.
Let us know what you think.


----------



## DangerClose (Oct 19, 2017)

Slipmyster said:


> What you are describing sounds about right for the stock tubes.
> Bright with not a lot of bass and not a lot going on with the soundstage.


More than anything, I think my stock tubes are too bassy.  Or to be more specific, too warm and muddy.  I probably wouldn't mind the warm if there was less mud.


----------



## Slipmyster

DangerClose said:


> More than anything, I think my stock tubes are too bassy.  Or to be more specific, too warm and muddy.  I probably wouldn't mind the warm if there was less mud.


There is lots of information in this thread on replacment tubes. 
I dare say that the manufacturing process of the Chinese tubes isn't as consistent as it could be so quality is sound may vary.
Mine sounded very thin and bright.
But this could depend on the headphone load may be ?


----------



## DangerClose (Oct 19, 2017)

Slipmyster said:


> There is lots of information in this thread on replacment tubes.
> I dare say that the manufacturing process of the Chinese tubes isn't as consistent as it could be so quality is sound may vary.


Regardless of whether someone thinks the stock tubes are bright or thinks the stock tubes are warm and muddy, I think we all agree the most important thing is that the stock tubes can be improved upon even with cheap replacements.

And for people just getting the amp who don't want to mess with more tubes, it's not like the stock tubes are awful.  Even with the stock tubes, it's a good amp in its price range, and beyond.

The headphone jack annoys me since it's embedded, the big pop sound when you first turn it on is annoying, the power cord is too short, etc, so it's not a perfect amp, but price is a big factor with this.


----------



## Slipmyster

DangerClose said:


> Regardless of whether someone thinks the stock tubes are bright or thinks the stock tubes are warm and muddy, I think we all agree the most important thing is that the stock tubes can be improved upon even with cheap replacements.
> 
> And for people just getting the amp who don't want to mess with more tubes, it's not like the stock tubes are awful.  Even with the stock tubes, it's a good amp in its price range, and beyond.
> 
> The headphone jack annoys me since it's embedded, the big pop sound when you first turn it on is annoying, etc, so it's not a perfect amp, but price is a big factor with this.



Fully agree.
It's a bit of a bargain.


----------



## dhaninugraha

Slipmyster said:


> Nice.
> Hope you like it. Don't judge it to much with the stock tubes they tend to ring like a bell every time you look at them.
> Let us know what you think.



For $46, it's a keeper. I'm rocking rMBP > Hifiman HM-101 > Mogami 2534 + Oyaide lookalike 3.5mm plugs > NS08E > HD25 (Mogami 2534 & Rean NYS231BG 3.5mm), and the whole shebang sounds -- for the lack of a better term -- balanced, at least to my ears.

Live recordings like John Mayer's _Where The Light Is: Live In Los Angeles_, Alicia Keys' _Unplugged_, this and this is a joy to listen to. Also John Mayer's "Gravity" (from _Continuum_) and Jason Mraz's "Butterfly" (from _We Sing. We Dance. We Steal Things.)_. Punch, dynamics, and details are pretty good for most commercial pop/rock/electronic/EDM/trap/RnB recordings, though I'm certain those who listen to those kind of music would want more (I know I do).

With the HD25, and my rMBP's volume set to max, I usually listen with the volume knob right on the 9 o'clock mark, turning at most 4 notches up for quieter recordings.


----------



## edulov

Hi. On the recent buy. Can you open it and look which op amps are installed in latest shipments?
I'll explain my interest afterwards.

Thanks in advance


----------



## dhaninugraha

edulov said:


> Hi. On the recent buy. Can you open it and look which op amps are installed in latest shipments?
> I'll explain my interest afterwards.
> 
> Thanks in advance



Looks like a pair of NE5532s:


----------



## edulov

Thanks. Still the same version. Think about rolling op amps too. You can find recommendations on head-fi. 5532 are old, but actually sound very good. Potentially you can improve lors, high trebble and resolution. But it will be heard in a really good cans only. BTW, a better soundstage (slightly) also is an option with another op amps.


----------



## Tom Steed

I have just put a pair of Burr Brown OPA2134PA opamps in and they sound good with the mullard e180f's. I'm waiting for a pair of muses02's to try. If they don't work so well i can always try them in my soundcard.


----------



## dhaninugraha

Looks like I'll be picking up a few pair of opamps from Mouser within 1-2 weeks: OPA2134, OPA2604, OPA2227, LM4562.
Valvo and Mullard tubes also comes to mind.

I think I need to cancel my PayPal account and credit cards...


----------



## Tom Steed

Tom Steed said:


> I have just put a pair of Burr Brown OPA2134PA opamps in and they sound good with the mullard e180f's. I'm waiting for a pair of muses02's to try. If they don't work so well i can always try them in my soundcard.



So i decided to get a pair of hd600's. Yes it was worth it. I play flat don't use eq and it's all there. Bass, mid's and high's but nothing is overpowering. A well balanced sound. I.m using the burr brown opamps with amperex 6688's with absolutely no complaints. I have a few more bits arriving soon and will see if the sound picture changes any.


----------



## erich6

I just got the HD6xx and I can report they pair well with the Nobsound NS-08E and Amperex JEP-6688's.  This little amp has plenty of power to give and lots of headroom with the HD6xx.


----------



## edulov

Just a comment about Burr Brown's compatible with this amp. They produce a darker sound. Not so accentuated, but I prefer neutral sound right from the gear.


----------



## edulov

This tiny guy can kill your ears even in 600 Ohm cans. That is why some people were crying that it lacks gain switch to deal with low-high ohm headpnones w/o touching volume button,


----------



## dhaninugraha

These babies just came in the mail. Left my hex keys at home though... Won't be able to try them out in the NS-08E until sometime tonight. *sigh*


----------



## Tom Steed

dhaninugraha said:


> These babies just came in the mail. Left my hex keys at home though... Won't be able to try them out in the NS-08E until sometime tonight. *sigh*


I got a pair of these to try today as well


----------



## dhaninugraha

Tom Steed said:


> I got a pair of these to try today as well



Cool! Which tubes are you pairing them with? I'm currently listening to them with the stock tubes on.


----------



## Tom Steed

dhaninugraha said:


> Cool! Which tubes are you pairing them with? I'm currently listening to them with the stock tubes on.


At the moment NOS mullard e180f's. I have 6688's to try as well and should be getting some Russian tubes soon.


----------



## Tom Steed

Tom Steed said:


> So i decided to get a pair of hd600's. Yes it was worth it. I play flat don't use eq and it's all there. Bass, mid's and high's but nothing is overpowering. A well balanced sound. I.m using the burr brown opamps with amperex 6688's with absolutely no complaints. I have a few more bits arriving soon and will see if the sound picture changes any.


Today i received a pair of dual opamps to try from Charles at Burson Audio. They are V5i hybrid amps, a mix of discrete components and a custom integrated circuit. They are a drop in component and can replace a multitude of differing opamps.  

 


The website states that they need a 'burn in' period of around 100hours. Which should be about 5-6 days as i don't turn the nob off.

My headphone amp is connected to the soundcard in my pc and my music is digital files, blu ray audio and streaming and other file formats. I use an ASUS Xonar essence stxII into the nob with e180f tubes output to HD600's and my first impressions, well it brought a smile to my face. The first file i played was 'on the run' from the pink floyd immersion box set. This is one of the busiest tracks i know, so much going on and everything was there in my ears. The headphones provide the soundstage and the amp drives it. I think it's a perfect match and hope it's gets better as they bun in.


----------



## Slipmyster

They look the business. Really neat.
I have a question about the volume pot if anyone can help.
Mine seems to have a bit of an imbalance toward the right hand channel is it possible to drop in an alps pot ?
Are they the same size ?


----------



## edulov

Slipmyster said:


> ...  a bit of an imbalance toward the right hand channel ...


Most probably (99%) a disbalance resides in slightly different (or even not so small) REAL electric specs of the tubes. It happens even for the NOB's, not even speaking about a weared second-hand. That is why many people pay extra for selected pairs, since a special testing device measures a set of electric specs for each tube and we can make the most equal pairs.
If disbalance is not so big and your audio source has a precise L/R balance control (ALL modern digital sound cards and operating systems offer this feature), make a realtime recording, measuring the signal strength for L and R, adjusting it through OS mixer or special sound driver feature.
Even more, some people don not recommend to use full sound card amplification (so called 100%), using 70-80% interval, where you can adjust your disbalance easily. Do not forget, that our amd is really powerful and you can compensate a volume drop turning an amp's knop instead of amplifying a sound card noises.

Tell us, if it helped.


----------



## Slipmyster

edulov said:


> Most probably (99%) a disbalance resides in slightly different (or even not so small) REAL electric specs of the tubes. It happens even for the NOB's, not even speaking about a weared second-hand. That is why many people pay extra for selected pairs, since a special testing device measures a set of electric specs for each tube and we can make the most equal pairs.
> If disbalance is not so big and your audio source has a precise L/R balance control (ALL modern digital sound cards and operating systems offer this feature), make a realtime recording, measuring the signal strength for L and R, adjusting it through OS mixer or special sound driver feature.
> Even more, some people don not recommend to use full sound card amplification (so called 100%), using 70-80% interval, where you can adjust your disbalance easily. Do not forget, that our amd is really powerful and you can compensate a volume drop turning an amp's knop instead of amplifying a sound card noises.
> 
> Tell us, if it helped.


Mine is connected to a Sony cd player so source isn't a problem.
I bought 2 matched pair of Russian 6j9's. The pair that is in now only have a few hours on them so I'm going to get the other pair out tomorrow and give them a try. May be swap them around a bit and see if i can level it up.
Thanks for the help


----------



## edulov

Warming up is happening for valves, but normally we are talking about 15 minutes max after swithing on. Measuring by ear is not a good idea actually. Download RMAA, they implemented realtime amplitude measurement for L/R, so you can see levels on the go.


----------



## dhaninugraha

I'm currently listening to the Spotify Premium on rMBP > NS-08E (stock tubes + Burson V5i SS opamps) > Senn HD25-1 setup. Max volume on the rMBP, volume knob is set a couple clicks past the 9 o'clock mark on the NS-08E. Connecting them both is a 3.5-to-3.5 I made out of Mogami 2534 and a pair of gold-plated Oyaide clone 3.5mm plugs.

First thing that I can say for certain, is that the V5i SS sounds airier than the stock NE5532s that came with the NS-08E. It also gives a better sense of ambience and realism in live recordings -- when I close my eyes, it's as if I could imagine which instruments are where and how low and/or far the clapping audience sits relative to the artist, and if said audience is chanting faintly from afar, or somewhere closer to the stage. John Mayer's _Where The Light Is: Live In Los Angeles_ is a good example of this.

More impressions to follow.


----------



## edulov

Thanks for sharing your experience.
I'd love to propose a small test, but for shure it happens in really good open cans.
Look for a losless Uriah Heep - The hanging tree. Best of all - some reissue/remaster, like the "It was 40 years ago" album. There in many places you must hear not just a good positioning and soundstage width, but be able to locate instruments in 3D.


----------



## Tom Steed

edulov said:


> Thanks for sharing your experience.
> I'd love to propose a small test, but for shure it happens in really good open cans.
> Look for a losless Uriah Heep - The hanging tree. Best of all - some reissue/remaster, like the "It was 40 years ago" album. There in many places you must hear not just a good positioning and soundstage width, but be able to locate instruments in 3D.



Ok, I tried this track in flac format. There was a lot of left/right positioning and all the instruments were well defined. I could separate them and they didn't blur together. That said it wasn't my fav Heep song. I prefer the Salisbury album as i knew the recording studio well and heard the acoustics first hand. 

At the moment i am using Russian 6j9's with the Vi5's. They are very bright and punchy in the midrange. I will be moving to the other tubes soon. Either way with a tube and op amp upgrade this little box punches well above it's weight. Depending on budget, you can go for the Vi5's at the top end and get a chip that is designed for audio presentation or at the lower end a normal audio op amp chip and as they say 'your mileage my vary'.

My setup is pc based:
Asus xonar essence stxII
Nosound with Russian 6jn, Mullard e180f and Amperex 6688. not matched valves but i found good deals on fleabay.
Sennheiser HD600


----------



## sup27606 (Nov 17, 2017)

Just put a pair of Burson V5i and now I hear all sorts of hissing sounds and low level hum. The noises do not change with volume. Also (weird), the hissing sound changes in intensity if I move around my headphone cable. The humming remains unaffected. The old opamps were dead silent. I guess, the opamps are defective. Anyone has any ideas? Thanks.

They sound phenomenal though.

Update: The hissing is completely gone now, but the low level hum remains. Its easily audible during quiet passages. I am sorry this turned out this way, because otherwise the opamps really make the amp shine, with clearly better imaging and treble details.


----------



## edulov

About opamp noise
1. Valve and opamp are connected in a very specific way in this amplifier
2. Opamp is not jaus a packaging. It has its internal scheme (a specific pin assignment) and electric parameters

When I made an opamp rollup, I looked for compatible devices with specific sound profile (neutral, wide, transparent & etc). But I made a note that they differ not only in amping current, but also have a slightly different specs. So when one of testees produced a notable backgound noise, I made a detailed comparision and found that being potentially soundwise better, its resistance and impedance numbers are different compared to others. Because forgetting about noise it sounded best from the bunch.

So, i'd recommend to try another tubes, even a stock ones to see, what happens with noise.


----------



## sup27606

I found the Burson ones both wide/deep and very detailed. That's why, despite the humming, I was just listening for hours yesterday. The sound is slightly warm which gives an almost speaker like feeling.

I will have to look for the factory tubes where I kept them, and once I find them, I will test with the new opamps.

Have you or anyone else face humming noise with the Burson, or is it just me? I am wondering whether this pair could be defective and whether to send them back (the window is short).

Assuming the amps are ok, and the noise is due to a mismatch in electrical parameters between them and the tubes, is it safe to continue using them? What can I do to mitigate the noise. Would changing the power supply help? Ha! I really like the sound.


----------



## edulov

Safe - yes. The difference is not that huge to damage, but keep listening noisy music? 
There is a small possibility that power unit isn't OK, providing lesser or higher voltage. If you have a tester or can lend it - make a check. BTW, twice I had an issue with a bad contact in a wall power socket which were causing noises. Take a look also.


----------



## sup27606 (Nov 17, 2017)

The noise is not loud, and only audible during quiet passages. Even when there is low conversation in the room, it becomes almost inaudible. I have tried to remove the thought of the noise from my head, so that I can enjoy music, with the hope that some day this issue will be resolved 

I have got a tester. I will check the power adapter tonight. There are big resources on the web for troubleshooting noise issues in amps, but many of those are for electronic experts, or even if I understand enough to follow them, I don't have the expertise to handle unexpected scenarios. If power turns out to be not the issue, I am not sure how to troubleshoot further though.

I already tried a different wall socket, and still had the issue. Thanks for the suggestions.


----------



## edulov

I hope we agreed that testing a completely different pair of bulbs may give a hint. It would be very rare that BOTH opamps came with the SAME ISSUE.


----------



## sup27606

Certainly. I will try to find the old tubes tonight. Also considering a battery pack to test for power issues.


----------



## Tom Steed

sup27606 said:


> Certainly. I will try to find the old tubes tonight. Also considering a battery pack to test for power issues.



You can also try different cables, from your sound source to the nob amp and if your headphone cable can be changed try that as well.
Make sure the earth wire from the circuit board to the back panel is still attached.  

Previously with different op amps I had hiss that changed when i moved the headphones, i reversed the cable and that cured it.#
With the Vi5's i have no noise, the only noise now is part of the recordings


----------



## sup27606

Tom Steed said:


> Previously with different op amps I had hiss that changed when i moved the headphones, i reversed the cable and that cured it.



I am also experiencing the same effect. when I move around the cable, the hiss reduces or becomes quiet. By reversing, did you mean, use a different cable? I am using the Sennheiser 6XX with the original cable it came with. I checked, the earth wire is securely connected to the chassis.



Tom Steed said:


> With the Vi5's i have no noise


Jealous!

About the hum, I notice when I twist the power connector while plugged into the amp socket, the hum reduces or goes off completely for very specific positions. Also, I tried a different set of tubes (factory ones) than the ones I am using (Amperex 6688) and the noise remained the same.


----------



## Tom Steed

sup27606 said:


> I am also experiencing the same effect. when I move around the cable, the hiss reduces or becomes quiet. By reversing, did you mean, use a different cable? I am using the Sennheiser 6XX with the original cable it came with. I checked, the earth wire is securely connected to the chassis.
> 
> 
> Jealous!
> ...



I was using Sony headphones and the cable had a 3.5mm jack at each end, i reversed it and it worked. The 6xxx use their own cable, maybe a replacement will make a difference.


----------



## edulov

The plugs of some cables could be disassembled and you will find a really bad soldering quality. Talking about Nob, its In/Out connectors are "deepened", so some cables could not be completely inserted, causing different sound distortions - I had this issue.


----------



## sup27606

Ok, I checked again today evening and now it is dead silent. Not sure what was going on before. I will continue to monitor for the next few days to see if the humming comes back.


----------



## sup27606

Update: The hum has come back. To check whether it's a power adapter issue, I powered the amp from a battery pack. Dead silent. So now I am thinking of two options: (1) get a ground loop eliminator like Ebtech Hum x, or (2) IFI iPower 9V adapter. I am skeptical about the second option, since it applies significantly more voltage than 6V, but it's also the cheapest. Not sure which way to go.


----------



## edulov

6V plus/minus a little. Slightly higher is better if you can't find a good 6V adapter.


----------



## sup27606

Any suggestion on a clean PSU, that won't be too expensive?


----------



## Tom Steed

Tom Steed said:


> Ok, I tried this track in flac format. There was a lot of left/right positioning and all the instruments were well defined. I could separate them and they didn't blur together. That said it wasn't my fav Heep song. I prefer the Salisbury album as i knew the recording studio well and heard the acoustics first hand.
> 
> At the moment i am using Russian 6j9's with the Vi5's. They are very bright and punchy in the midrange. I will be moving to the other tubes soon. Either way with a tube and op amp upgrade this little box punches well above it's weight. Depending on budget, you can go for the Vi5's at the top end and get a chip that is designed for audio presentation or at the lower end a normal audio op amp chip and as they say 'your mileage my vary'.
> 
> ...



I moved back to the amperex 6688 tubes for a while and left them to warm up. they sound smoother than the russian tubes. My ears aren't good enough to accurately describe the differences, they are all good but some are gooder than others 
I finally moved back to the mullard nos e180f's and these are the ones i prefer. For me they match perfectly with the Vi5 op amp. The original nosound performs well and the china valves and op amp just work. But this thread proves that with some changes it can be much more. After months of searching op amps and valves, i think i'm dialled into the sound i like and Charles at Burson Audio put the cherry on the cake by letting me test the Vi5's. I would buy these and may do so as my sound card can roll op amps.


----------



## dhaninugraha

It's been a while since I wrote my initial impressions about the V5i SS on this amp... And now I must say that I don't wanna return the V5i SS to Charles  j/k.

To echo what others have said; the V5i sounds big and punchy, has good imaging/sense of space, mids that I would say as upfront, detailed and borderline bright but very enjoyable still.

Rag'n'Bone Man's _Human_, Iron & Wine's _Flightless Bird, American Mouth_, Damien Rice's _The Blower's Daughter_, Sarah McLachlan's _Angel_, and James Blunt's acoustic rendition of _1973_ exemplifies my point about the mids and details. Vocals has this... intimate presence, yet there's this sense of airiness/space, without being artificially so. I can't exactly describe it. All I can say is, I'm having a really, really good time listening to all of them on repeat, with the stock tubes + V5i SS + HD25-1 combo.

Pop and electronic music sounds good too, with just enough punch and low extension, sparkly details, and good sense of presence to make things lively. Listening to David Guetta, Martin Garrix and Clean Bandit gives the kind of feeling you get when you hear a good set of stereo playing such songs at the local AV shop: it sounds fun and makes you wanna lowkey headbang, but not the enveloping, lows-so-low-you-could-feel-it-on-your-chest club feel.

Now excuse me, I've got a playlist full of Top 40 EDMs to listen to...


----------



## Slipmyster




----------



## NotMuchToLearn

I just ordered one of these off Amazon today (or a copy of this at least).  The one I ordered is found here.  It's a bit odd since the pics look like a copy of this nobsound amp, except it takes 12v instead of 6v, AND the brand in the pics (Hoomya) doesn't match the brand in the description (Shuogou).  Even the description exactly matches the nobsound's.  Everything about this is sketchy but I wanted to try it out.  Also since this thread seemed to like them, I ordered some soviet tubes from ebay and I'm excited to try them out in a week or so when they arrive: 

2x 6j9p-E NOS from 1975 
4x 6j20p NOS date unknown

I was tempted to buy some tesla tubes too but they were a bit much once I priced in shipping so I skimped out.  I found the same Hoomya amp on Amazon's Japan site and it has stellar reviews so I really hope I am getting what was pictured in the listing.

One of the reasons I got this was because my Audiotechnica M50x's little plastic piece that holds the cups to the ears broke off so I ordered some new AKG m220s from Massdrop.  Also I rebuilt my computer and the new mobo didn't have a compatible pci-e slot for my soundcard.  I will definitely  be experimenting with this amp and both headphones.  I'm hoping the tubes will really help the quality.  Also if anyone knows about the compatibility of the 6j20p tubes let me know.  I bought them because they said they were equivalent to 6688 and E180F tubes and they were a steal.


----------



## riffrafff

NotMuchToLearn said:


> I just ordered one of these off Amazon today (or a copy of this at least).  The one I ordered is found here.  It's a bit odd since the pics look like a copy of this nobsound amp, except it takes 12v instead of 6v, AND the brand in the pics (Hoomya) doesn't match the brand in the description (Shuogou).  Even the description exactly matches the nobsound's.  Everything about this is sketchy but I wanted to try it out.  Also since this thread seemed to like them, I ordered some soviet tubes from ebay and I'm excited to try them out in a week or so when they arrive:
> 
> 2x 6j9p-E NOS from 1975
> 4x 6j20p NOS date unknown
> ...



That looks similar to mine, but mine is labeled "Nobsound," like this one.  It also came with Chinese 6J9 tubes.  I replaced them with GE 6688 tubes (and the op-amps with NS LM4562NA parts) (not sure if I really heard a difference).  Plus, I ripped out those silly blue LEDs under the tubes, lol.


----------



## erich6

NotMuchToLearn said:


> I just ordered one of these off Amazon today (or a copy of this at least).  The one I ordered is found here.  It's a bit odd since the pics look like a copy of this nobsound amp, except it takes 12v instead of 6v, AND the brand in the pics (Hoomya) doesn't match the brand in the description (Shuogou).  Even the description exactly matches the nobsound's.  Everything about this is sketchy but I wanted to try it out.  Also since this thread seemed to like them, I ordered some soviet tubes from ebay and I'm excited to try them out in a week or so when they arrive:
> 
> 2x 6j9p-E NOS from 1975
> 4x 6j20p NOS date unknown
> ...



The 6j9p should work; not sure about the 6j20p.  It's a bit hit-or-miss with Soviet tubes.  I highly recommend NOS Amperex JEP-6688 (I have 1964 USA production and they sound great.)


----------



## AthenaZephyrian

Anyone know how this compares to a Little Dot I+ with rolled tubes and op-amp (or stock, I guess)?  OP said it was better than the Vali, and the Vali competes with the LDI+.  

And how's it stack up to its miniature, titankilling cousin, the unfortunately-unrollable NS-O1E?  I found the NS-O1E goes to-to-toe with the LDI+.


----------



## AthenaZephyrian

riffrafff said:


> That looks similar to mine, but mine is labeled "Nobsound," like this one.  It also came with Chinese 6J9 tubes.  I replaced them with GE 6688 tubes (and the op-amps with NS LM4562NA parts) (not sure if I really heard a difference).  Plus, I ripped out those silly blue LEDs under the tubes, lol.



Bloody hate the blue LEDs on all my electronics.  If I wanted it blue I'D MAKE IT BLOODY BLUE. [/rant]  Totally interferes with the lovely tube glow.  I blacked out the LED on my NS-O1E.


----------



## Dan-Fi (Sep 2, 2018)

Hey guys, glad to see that this thread is still alive with Nob users! I just thought I'd chime in on a possible suggestion for users who like me, have been battling with the issue of background hissing on this amp. I'm sure it's something to do with the power plug or adapter (if I wriggle the power jack, I can minimise the hiss, but can still hear some) and I tried different powerpoints, extension cords and adapters over the past couple or so years since I bought this amp, but the hissing persisted. So I neglected it for a long time and it collected dust by my bedside table...

Well today is Fathers Day in Oz and I got to spend some "me time" to lie in bed and listen to some music and I thought I'd try out the Nob once again. I have an LG V10 and there are posts about activating its high impedance mode to make some headphones shine on this phone and one suggestion was to use a volume attenuator, like the one Shure supplies with its higher end IEMs. You can buy this separately and I did so a while back to use my Grados on this phone. It was only today I thought (yes I'm getting older and slower with thought processes!), why don't I try this out on the Nob and see if this attenuator can mitigate the hissing? Well lo and behold, it did the trick! No hissing anymore, except if it came from the recording! I can finally listen to classical music on the Nob without any background hissing! 






So now I'm back in love with this amp and listening right now to Karajan using a matched pair of Dario E180F tubes and my Grado SR325is (yes I do like classical with this headphone!). Hope this helps out for some of you Nob users!


----------



## erich6

Dan-Fi said:


> Hey guys, glad to see that this thread is still alive with Nob users! I just thought I'd chime in on a possible suggestion for users who like me, have been battling with the issue of background hissing on this amp. I'm sure it's something to do with the power plug or adapter (if I wriggle the power jack, I can minimise the hiss, but can still hear some) and I tried different powerpoints, extension cords and adapters over the past couple or so years since I bought this amp, but the hissing persisted. So I neglected it for a long time and it collected dust by my bedside table...
> 
> Well today is Fathers Day in Oz and I got to spend some "me time" to lie in bed and listen to some music and I thought I'd try out the Nob once again. I have an LG V10 and there are posts about activating its high impedance mode to make some headphones shine on this phone and one suggestion was to use a volume attenuator, like the one Shure supplies with its higher end IEMs. You can buy this separately and I did so a while back to use my Grados on this phone. It was only today I thought (yes I'm getting older and slower with thought processes!), why don't I try this out on the Nob and see if this attenuator can mitigate the hissing? Well lo and behold, it did the trick! No hissing anymore, except if it came from the recording! I can finally listen to classical music on the Nob without any background hissing!
> 
> ...



Happy Father's Day and glad this setup works for you.  I've noticed that high impedance headphones won't pick up the power source noise but low impedance cans will.  It's annoying because the amp sound quality is excellent otherwise.  I was going to try different power sources but looks like you've tried that to no avail.


----------



## Dan-Fi

Thanks @erich6 for the well-wishes. The highest impedance headphone I have is an old AKG K145/S which I think is rated at 200 ohm, but I could still hear hissing with them. However, as you'd indicated, higher resistivity certainly lowered the volume of the hissing. You can get one of those Shure volume attenuators on Ebay for about AUD$20-$25 when I purchased one a while ago.


----------



## riffrafff

I ran a wire from the case to NEMA-ground to eliminate the hum I was getting on mine.


----------



## rlisin

Has anyone tried this little guy with very low impedance headphones, 4-8 ohms? I have a few like that (DT48, some old Pioneers), wondering whether it's safe to connect them to this amp. Of course with usual safety precautions, connecting after the amp is on, with volume down. Not asking about SQ and background noise, just safety for headphones and the amp.


----------



## erich6

rlisin said:


> Has anyone tried this little guy with very low impedance headphones, 4-8 ohms? I have a few like that (DT48, some old Pioneers), wondering whether it's safe to connect them to this amp. Of course with usual safety precautions, connecting after the amp is on, with volume down. Not asking about SQ and background noise, just safety for headphones and the amp.



I'm not sure about whether it would be safe or not but...I think regardless it would not be a good fit and overkill.  I use 32 ohm &  pretty sensitive headphones with it and can barely turn the volume up past the 7 o'clock position (sometimes can get to 8 o'clock with quiet recordings).


----------



## rlisin

Different story. I'm talking about VINTAGE 4-8 ohm headphones that are not easy to drive at all, they were designed to work with headphone outputs of amplifiers and receivers from the 1970s, or even their speaker outputs. For example, your average smartphone won't have the juice to drive them, but it will easily drive the majority of modern 16-50 ohm cans. 
Also, I can make up my own mind with regard to convenience and SQ of such connection as soon as I have a listen. My question is about safety only.


----------



## K31TH3R (Oct 10, 2018)

rlisin said:


> Different story. I'm talking about VINTAGE 4-8 ohm headphones that are not easy to drive at all, they were designed to work with headphone outputs of amplifiers and receivers from the 1970s, or even their speaker outputs. For example, your average smartphone won't have the juice to drive them, but it will easily drive the majority of modern 16-50 ohm cans.
> Also, I can make up my own mind with regard to convenience and SQ of such connection as soon as I have a listen. My question is about safety only.



Worst case scenario is either the headphones won't be very loud or just won't sound very good, or the amp overheats and shuts down. From what I read the Nobsound amps will shut down when they overheat, so I'd imagine they also have overcurrent protection. The headphones can probably handle far more current than the amp will output. Power supply output is quoted at 6v, 2000ma. But 6v at 8ohms is 7500ma, and 4ohms is 1.5A so I'm guessing the amp or power supply will just shutdown if you crank the volume on 8ohm or 4ohm load. I wouldn't have any worries just plugging it in and turning up the volume and seeing what happens.

I ordered the Nobsound NS-01E and will be receiving one tomorrow. I've read the NS-01E has better frequency response at the low end, as well as more gain than the NS-08E. My current setup is just slightly too analytical/cold and lacks just a little bit of mid-bass so I figured I'd see what the Nobsound has to offer and use my Pimeta as a pre-amp. The mids improved a lot on my 990's after I recabled them and now the mids are overpowering the mid-bass.

I don't have high expectations for the Nobsound, but at $46, why not give it a go?


----------



## riffrafff

K31TH3R said:


> I don't have high expectations for the Nobsound, but at $46, why not give it a go?



I have one at work, with NOS GE 6688 tubes.  Works okay in my fairly noisy environment with closed cans (AKG K553).


----------



## rlisin

K31TH3R said:


> Worst case scenario is either the headphones won't be very loud or just won't sound very good, or the amp overheats and shuts down. From what I read the Nobsound amps will shut down when they overheat, so I'd imagine they also have overcurrent protection. The headphones can probably handle far more current than the amp will output. Power supply output is quoted at 6v, 2000ma. But 6v at 8ohms is 7500ma, and 4ohms is 1.5A so I'm guessing the amp or power supply will just shutdown if you crank the volume on 8ohm or 4ohm load. I wouldn't have any worries just plugging it in and turning up the volume and seeing what happens.



Thanks, I'll give it a shot then.


----------



## Slipmyster

Hi
I have just had to replace the volume pot in my ns-08 due to an imbalance on the left channel. I was looking at the blue LED's
Has anyone disconnected them or do they do more than just light up the tube's ?

Thanks


----------



## riffrafff

Slipmyster said:


> Has anyone disconnected them or do they do more than just light up the tube's ?



Just clip them out.  I de-soldered mine, but either way works.


----------



## Slipmyster

riffrafff said:


> Just clip them out.  I de-soldered mine, but either way works.


Thank you


----------



## Tinker22

Has anyone measured the voltage of the power supply that comes with this amp? Preferably loaded, in other words when plugged in so one would have to probe the voltage with the unit opened up. Mine arrives in a couple of days, along with some matched Mullard valves. Excited for sure. I am considering fitting a linear regulator in place of the PSU. I am thinking that the power supply is probably not fantastic. I nice noise-less stable supply would be good.


----------



## RickeyM (Nov 2, 2018)

I just ordered one of these yesterday and also ordered a pair of GE 6J4 tubes. i see from a pic here that the op-amps are in sockets which is handy because I have some LM4562a's handy and a pair of some of those discrete op-amps (not Burson's) so I'll be doing a little experimenting   Currently the only 'phones I have are a pair of surprisingly good SMS Audio Streets and a pair of Radio Shack earbuds but I may add another pair of cans before years end. I'll post back in a few days about my impressions.


----------



## RickeyM (Nov 2, 2018)

*HEY, WHAT GIVES???* OK I got my Nobsound NS-08E and the tubes and sockets are 7-pin ones not the 9-pin ones I've seen in pics in this thread. The only markings I can decipher on the tubes are 6J3. Other than that it looks just like the pics, it's in fine condition and is working great. Sounds pretty good too. Playing some songs off Amazon Prime > RCA tablet > UGREEN USB converter > Nob > SMS Audio Streets. Of course this is with the stock tubes & Op-amps. This setup seems kind of forward in the mids, recessed a bit in the bass, nice and clear in the highs. Granted I haven't tried any other sources or rolled any tubes or Op-amps yet but so far I'm liking it. Now about them tubes...


----------



## Slipmyster

RickeyM said:


> *HEY, WHAT GIVES???* OK I got my Nobsound NS-08E and the tubes and sockets are 7-pin ones not the 9-pin ones I've seen in pics in this thread. The only markings I can decipher on the tubes are 6J3. Other than that it looks just like the pics, it's in fine condition and is working great. Sounds pretty good too. Playing some songs off Amazon Prime > RCA tablet > UGREEN USB converter > Nob > SMS Audio Streets. Of course this is with the stock tubes & Op-amps. This setup seems kind of forward in the mids, recessed a bit in the bass, nice and clear in the highs. Granted I haven't tried any other sources or rolled any tubes or Op-amps yet but so far I'm liking it. Now about them tubes...


They have changed the tubes on the new one. According to there website the 6j3 is supposed to have better sound.


----------



## RickeyM

Slipmyster said:


> They have changed the tubes on the new one. According to there website the 6j3 is supposed to have better sound.



Oh OK, I was slightly worried that I didn't get the genuine article. A couple of things I did notice. The power plug fits nice and snug and the tubes aren't microphonic. No hum either.


----------



## Tinker22

Got mine today. Awaiting my Mullard E180F tubes which should arrive tomorrow. Nonetheless I am impressed even with the Chinese tubes out the box with no burn-in. I got the old version, which I am happy about as then at least I can use the Mullard tubes.


----------



## Slipmyster

You'll have to let us know what you think of it.
Im really happy with mine with the Russian tube's.


----------



## Tinker22 (Nov 4, 2018)

Still waiting for the Mullards. They're in the post from the UK so I am hoping I get them tomorrow. Anyway, I had another theory and would be interested to hear thoughts on it. So a typical setup might be as follows:

Music player (PC, Phone, tablet, whatever) -> DAC -> Nobsound NS-08E - Headphones.

We all know the NS-08E is a hybrid amplifier. So the tube acts as a voltage follower, or a buffer. It does not provide any amplification. But since the audio signal passes through it, it effectively provides the "tube effect" in terms of response. Hence the different quality sounds when using different tubes and the different sound versus just using a DAC -> Solid State Amp -> Headphones. So it effectively filters the audio with the tube sound. This is my take on it anyway. The amplification in the NS-08E is provided by some solid-state op-amps at the output, after the tubes.

Now with any amplifier, the distortion and harmonics are higher when the input signal amplitude is larger. The harmonic distortion contributes to the tube sound, according to my understanding. So my guesstimate theory is that we should maybe be pumping maximum amplitude through the valves. This means for a given listening volume, we should crank up the volume on the music player to maximum while setting the volume on the NS-08E to minimum. Balancing the volume in this way means maximum audio amplitude passing through the valves.

Maybe this results in a better sound. I don't know. Just thought I would throw this out there for some opinions either way.


----------



## RickeyM

Tinker22 said:


> Still waiting for the Mullards. They're in the post from the UK so I am hoping I get them tomorrow. Anyway, I had another theory and would be interested to hear thoughts on it. So a typical setup might be as follows:
> 
> Music player (PC, Phone, tablet, whatever) -> DAC -> Nobsound NS-08E - Headphones.
> 
> ...



Hmm, like driving  my NS-08E from the "line outs" of my CD player. Higher output than any phone or media player. Sounds great this way even with the stock tubes.


----------



## RickeyM (Nov 5, 2018)

I just got my tubes in. First report, the GE's must have been defective or damaged in shipping. All I got was a high pitched whine sound and no music. Very microphonic as well. The Amperex tubes are very good. The mids are tamed and the bass is stronger yet more detailed. The highs are nice and clean as well. Now I'm wondering should I spend more money rolling other tubes or quit while I'm ahead? The Mullards and other Amperex tube seem to be more expensive. For now I'll enjoy some music  

EDIT: maybe the 6J4's aren't compatible after all?


----------



## toon05 (Dec 2, 2018)

Hi, could I just ask the guy (RickyM) who purchased the 'New Upgraded' version of the Nobsound where he bought it from as I've just ordered one from Amazon here in the UK and was under the impression as stated on their website it should be a 6j9 which I have tubes for, but just finishing reading your article RickyM you were supplied with a 6j3 amp, I'm praying not from Amazon as I'm likely to receive the same, ok I can send it back or keep it but with 3 sets of extra tubes I'd feel rather.....Erm...miffed for want of a better phrase. Can 'RickyM' or 'Tinker22' help me out on this one? Kind regards. ps....if it goes 'Pete Tong' then I guess someone in the UK is going to get a bargain!...


----------



## toon05 (Dec 4, 2018)

toon05 said:


> Hi, could I just ask the guy (RickyM) who purchased the 'New Upgraded' version of the Nobsound where he bought it from as I've just ordered one from Amazon here in the UK and was under the impression as stated on their website it should be a 6j9 which I have tubes for, but just finishing reading your article RickyM you were supplied with a 6j3 amp, I'm praying not from Amazon as I'm likely to receive the same, ok I can send it back or keep it but with 3 sets of extra tubes I'd feel rather.....Erm...miffed for want of a better phrase. Can 'RickyM' or 'Tinker22' help me out on this one? Kind regards. ps....if it goes 'Pete Tong' then I guess someone in the UK is going to get a bargain!...


Just received the amp and its a 6j9 thankfully, I'll probably give the stock tubes a good go at first before attempting some rolling and op amps as well, sounds nice so hopefully it'll last a bit............wonder what the upgraded version sounds like.....maybe another day.....


----------



## RickeyM (Dec 4, 2018)

Yeah, I got mine from Amazon and in the description it does say the package contains 6J9 tubes. This leads me to believe Amazon UK still has the first models in stock and they're shipping those out first. BTW, what are the tubes you have? I have the Amperex tubes and LM4562na Op-amps and it  sounds great. I get the feeling that with a really great set of cans it would be killer.


----------



## toon05 (Dec 5, 2018)

RickeyM said:


> Yeah, I got mine from Amazon and in the description it does say the package contains 6J9 tubes. This leads me to believe Amazon UK still has the first models in stock and they're shipping those out first. BTW, what are the tubes you have? I have the Amperex tubes and LM4562na Op-amps and it  sounds great. I get the feeling that with a really great set of cans it would be killer.


Hi and thanks for the reply, got some Mullard E180F's from 'Yitry' on EBay and a pair of Russian 6j9's (I think) ordered off a reliable seller ' Audiozomba' both a matching pair and around £18 for a pair, then a matching pair of again Russian 6j9's from a foreign European seller 'Brandmix'£12 the pair so I've plenty of mixing and matching to do along with op amps as well, I've got a pair of hd600's from years and years ago, Richer Sounds were selling them cheap back then for around £45 a pair, forgot I had them and how good they were! But at the moment I'm just listening to it through a cheap and nasty pair of Betron's!!!! Still sounds good though....Amperex WAY to expensive for me to get posted in from the States but you never know...Cheers.


----------



## finubi

My Notebook, Dell E4300 sounds like crap on the headphone output, also the volume is to low with Beyerdynamic DT250Ohm. Will this thing help or do I need to get an external DAC?


----------



## Tom Steed

Yes, it will help. I just plugged into my latitude 6430 using winamp with no adjustment it sounded fine on my HD600's


----------



## finubi

I received mine today. And mine dont mak'e noises when i hit the tubes ore the case. Did the change the design?


----------



## finubi

Stupid question, but could I use a 12V 2A to increase volume or would it damage the unit?


----------



## edulov

Yes, it will damage the unit. Valve is a 6.3V unit. OpAmps must use recommended 5-15V, so if you WANT it won't be harmful to use 6.5V with the same current as a stock PSU does.


----------



## finubi

I made an error. Systemvolume was on 100% but Firefox only on 20%. Now this Amp is crazy loud.


----------



## Sean Davenport

Hi All, my first post!
I bought this amp from Amazon UK and got the newer 6J3 version, however I had already gone out and bought some Tesla E180F NOS valves which I found are completely different. are there any upgrade valves for the 6J3 valves that anyone has tried yet?
Thanks all!


----------



## edulov

Hi. No to your question, but officially 6Ж3 was replaced by better 6Ж4П (6AU6). It is one detail to look for compatible valves. The other one that looking at direct analogues 6AG5/EF96 and general behavior knowledge look for Mullard, RCA first. Then - Russian ones. If you like leaner sound but neutral and balanced - try GE (General Electric). Remember, that according to Russian specs valves with codes terminated with letter П normally have better parameter and longer life span, so their analogues formally are better options. Keep us informed, pls!


----------



## Sean Davenport

Thanks, so these https://www.ebay.co.uk/itm/M8100-6A...d:g:IbcAAOSwhcJWJhmX:rk:2:pf:1&frcectupt=true would be good options then? I assume posting links like this is acceptable? if not I'll take it down.
Cheers.


----------



## edulov

Nope. You need these https://www.ebay.co.uk/itm/MULLARD-...e:g:ce4AAOSwm5xcMjbI:rk:1:pf:1&frcectupt=true


----------



## finubi

Do you think the female audio jacks will last a long time? They look very cheap.


----------



## Sean Davenport

edulov said:


> Nope. You need these https://www.ebay.co.uk/itm/MULLARD-...e:g:ce4AAOSwm5xcMjbI:rk:1:pf:1&frcectupt=true


Its a shame they only had one, I'll keep looking for a pair. Thanks.


----------



## Tom Steed

Sean Davenport said:


> Its a shame they only had one, I'll keep looking for a pair. Thanks.



Just search for EF94 or 6AU6 https://www.ebay.co.uk/itm/2x-Fishe...h=item1cc63976ca:g:JyoAAOSwCXxcM8ha:rk:2:pf:0


----------



## RickeyM

Sean Davenport said:


> Hi All, my first post!
> I bought this amp from Amazon UK and got the newer 6J3 version, however I had already gone out and bought some Tesla E180F NOS valves which I found are completely different. are there any upgrade valves for the 6J3 valves that anyone has tried yet?
> Thanks all!


I used Amperex tubes in mine and I like 'em a lot. Others have used Russian tubes.


----------



## edulov

Sorry, forgot about Amperex. Definitely a good ones


----------



## edulov

About audio jacks. Mine are fine, even being cheap. But, as noted many times for many equipment and cans, audio cables make difference, in case of this amp you need good ones for input and output.
You can save some money buying HiFi microphone ones. Use the same HQ cables & hardware, but are sold cheaper. Just be sure you can insert selected one in the smaller front hole or the jack pin is longer.


----------



## hiroshi976

Hello everybody.
it's my first post here on the forum. I'm a new user. I bought a Xuanzu X2-U808, same  to Nobsound ns-08e, indeed the Nobsound is a rebranded Xuanzu. The Nobosound pcb seen here, the few photos were branded Xuanzu. I preferred the Xuanzu to the nobsound, I did not want  have the "new" version with the 6J3 tube.
I wanted a tip for modding. I read the discussion, the top seems to be Mullard E180F, with op Burson V5I-D? Correct?
Recommended alternative to burson V5I, op economic but performing?
Another note, power supply seems the weak point. how could it be improved?
have advice?

thank you very much, and sorry my english!
kind regards
Hiro


----------



## edulov

If you need "safe" options w/o paying too much, order any or Mullard/RCA/Amperex. This amp also benefits from opamp upgrade, but you have to see which ones you have first, may be they already installed better ones?
About power supply, look for any with the very familiar specs, +5% max. There are some used for quality equipment, there some multi-voltage units. I would say that prices could vary from 5$ to 150+$ If you have friends in technical/physics university departments, talk to them first.


----------



## hiroshi976

thank you!
I already ordered on ebay, a pair Mullard E180F. The amp should arrive tomorrow, tubes next week!
Which opamp are usually installed? Which are the best?

Does anyone have the Xuanzu?  I bought this


----------



## edulov

look at your first. I placed my IMHO or in this thread, or in other one dedicated to this amp.


----------



## finubi

I can hear electric static when I turn on the amp for maybe 5 Minutes, then it is gone. Also my volume control is not even on all settings. Are these known problems?


----------



## Slipmyster (Jan 19, 2019)

finubi said:


> I can hear electric static when I turn on the amp for maybe 5 Minutes, then it is gone. Also my volume control is not even on all settings. Are these known problems?


The noise when you turn it on is normal.
Just plug your headphones in after you've turned it on.
I had the same problem with the volume control on mine. i hade to change the volume pot.


----------



## finubi

I did not mean the popping sound, I mean electric noise for 5 Minutes, weird. They dont have good qulity control. My first unit had an somehow broken female DC jack but a good potetiometer.


----------



## hiroshi976

Received  yesterday. I did some tests. It works perfectly. No pop noise during music I only hear "click/crack noise"  when turned it on.
Great sound. This morning I improved the power supply. I installed an EMI filter and change power supply box.
The opamps installed are NE5532P. I'm waiting Mullard E180F for first upgrade.

Do you recommend a combination of OpAmp with these tubes?
thank you


----------



## edulov

Lot of people will appreciate only this change, since installing better opamps will add details in general and improve "high" highs. Slightly widen a sound scene. But to hear these changes, you'll need really good cans. Since your profile does not include information, I can not tell.


----------



## hiroshi976

did you replace them? I have a Sennheiser HD518 and a Alessandro Grado MS1, entry level headphone but good sound (imho)


----------



## edulov

Overall good cans, but Sens won't give you enough highs and are not very good for soundstage, MS1 are tuned, good sound stage but can not provide enough lows to hear all tube rolling change. But with MS1 you will hear all opamp improvements in mids and highs. Recon to give you a pair of days to "dig" for all posts about compatible opamps in DIP casing. You can try some, but if a descriptions mentions "dark" sound, do not go for that option it you like live instruments and real vocals.


----------



## finubi

Are the tubes amp the sound or are they just preamps?


----------



## edulov

Hybrid. Opamp + tube


----------



## hiroshi976

i have modded and upgrade power supply. I inserted an emi filter. now go much better!


----------



## Machiventa

Hello, is the newer model still considered a decent amp? How do you know which version you're buying?


----------



## finubi (Apr 20, 2019)

Î think they just replaced the tubes, beside from this it is still the same model.

I found another problem, I think they deliver a power supply with a wrong DC plug.
The right one fits tight and it is slightly shorter.
Is this another DC type or just better quality?


----------



## N3v3rmind

just ordered a my 6j9 amp, a pair of mullards and a pair of LM4562.

Question, when desoldering the blue leds, has the tube socket needs to come off?

thanks,
dan


----------



## Slipmyster

N3v3rmind said:


> just ordered a my 6j9 amp, a pair of mullards and a pair of LM4562.
> 
> Question, when desoldering the blue leds, has the tube socket needs to come off?
> 
> ...


You should be able to get to the led's from underneath easy enough


----------



## JasonFH

I've been having a lot of fun with this little amp. I think I have the newer version and have some questions on op-amp rolling.

Does anyone know if the two internal op-amps run in series or one for each L & R channel of the output? I picked up some LT1364CN8 opamps (5 actually) and if I replace both of the NE5532 amps with the LT1364CN8, I get a loud and nasty buzz which seems to come from both L & R channels. If I just replace one of the op-amps with the LT1364CN8 and leave one as a stock NE5532 no buzz. No matter which combo I use as soon as both of the op amps are LT1364 they generate an awful buzz. (Tried all 5 of my LT1364s)

Any ideas?


----------



## edulov

Hi
I had the same problem with LT's, since their electrical params are not the same as NE. They are compatible, but not fully.


----------



## TheSands

edulov said:


> Hi
> I had the same problem with LT's, since their electrical params are not the same as NE. They are compatible, but not fully.



Hi,

so what opamps would you recommend? I have Rev. 8.0 of the board HY-A-U808-A. I read some pages earlier that someone replaced them with BB OPA267(?).. Are these fully compatible (I'm sorry, but I'm still new in this field).

Thanks a lot!


----------



## thomaskong78

I had been happy to drive HD 800S with Chord Dave Dac direct.

Sound & Vision – 21 Jun 16





*Tube Amps for Pocket Change Nobsound NS-08E*
Nobsound NS-08E Performance Features Ergonomics



I happened to come across above review.

Upon relying Amazon return policy, i pulled the trigger for it.

I did not expect any improvement by the amp.

It there is no significant deterioration vs direct Dave connection, it would have been nice.

On the contrary to my lower expectation, it made sound more exciting without harsh edge added.




1500×1500

https://www.amazon.com/Fairytales-Original-Master-Dogrobosz-Toneff/dp/B01D8QBNLM/ref=tmm_acd_swatch_0?_encoding=UTF8&qid=1573691594&sr=8-4


This is one of my favorite Jazz recording that I had enjoyed since 1999.

This CD sounds more natural with amp than through Dave direct.

Transparency got reduced by tiny bit but to tolerable extent.

It will work wonder for less Dac than Dave.

I am also going to do tube rolling with some Nos tubes.

RTC 5654 RT


----------



## Slipmyster

thomaskong78 said:


> I had been happy to drive HD 800S with Chord Dave Dac direct.
> 
> Sound & Vision – 21 Jun 16
> 
> ...


For the money they are a cracking bit of kit.
I've had mine for a while now in regular use with Russian long life tube's and it's been superb.


----------



## kkagan (Dec 26, 2019)

On a whim I bought this amp (the Nobsound NS-08E), it's impressive -especially for $50.  Can someone recommend a DAC to pair it with?  I listen to music on my Android Phone & Senn 599; with the addition of the NS-08E, I'm hoping to improve the setup with a small DAC as well.  Thanks all.


----------



## Tinker22

I have paired mine with a...

*FiiO E10K Headphone Amplifier and DAC*


----------



## kkagan

Thanks Tinker, I'm looking for just a DAC, not a DAC Amp combo, though I'm sure there's a way to bypass the amp on the E10K.


----------



## JasonFH

I was very happy with the USB-C to 3.5mm DAC from Samsung.  https://www.samsung.com/us/mobile/m.../usb-c-headphone-jack-adapter-ee-uc10juwegus/ 

I bought it because I have a Note 10, but then thought why not try it on a USB-C port on my laptop. I was very happy with the results. Windows seems to think it can do higher bit and sample rates than it advertises. Not sure if that's true or not and I won't go into the sample rate debate, but I'm very happy with it. 

It sits between my laptop dock and NobSound NS-08E. Listening primarily with Sennheiser 660s headphones. I bought two more, one for the office, one for home and one for travel.


----------



## kkagan

Thanks Jason, I'll take a look.


----------



## alexbau

Slipmyster said:


> For the money they are a cracking bit of kit.
> I've had mine for a while now in regular use with Russian long life tube's and it's been superb.


Hi Slipmyster, where did you find these Russian tubes? do you have the model nr? thanks!

- Alex


----------



## Slipmyster

alexbau said:


> Hi Slipmyster, where did you find these Russian tubes? do you have the model nr? thanks!
> 
> - Alex


Hi
I bought the tubes off ebay. 
They are the long life 6J9E
There are plenty on there at the moment. 
Hope this helps.


----------



## Hashi8888

edulov said:


> I'v got a question on tube rolling, also I have some general comments and results of op amp rolling. Thus I'll post them here.
> *Philosophy.*
> It does not matter how many times it was said or written, people still think that getting HQ is possible only from costly units. Gear is very important, especially for good headphones, especially high impedance ones (250 Ohm and above). But the result highly depends both on components quality and electrical/electronic design. Amplifier in mention has a simple, robust and smart design, so SQ mostly depend on components. Valve/tube is used as a buffer for inverse op amp connection where the buffer actually is a dynamic closed link which defines a big “cut” of SQ pie. But it also means that rolling op amp may improve or damage SQ. And – more rarely dynamic electrical connection between valve and op amp is unbiased giving sound artifacts and/or additional noises.
> The other side of the mirror is more complicated. SQ is flexible. Some elements like details, resolution, wide soundstage always count. Many other elements, especially quantity of bass and treble as a control over them are subjective. So I’ll mention only undeniable improvements.
> ...




Hi,

I followed this old post. I bought $70 worth of 6688A tubes thinking they are the correct ones. What is going on? I just received the Amperex 6688A tubes and they are 9 pin.
The Nobsound NS-08E is 7 pin tubed. Hitting my head on the wall now, got tubes and can’t use them.

Did Nobsound NS-08e change from 9pin to 7pin? Is this where I screwed up? Ugh...


----------



## rlisin

Did Nobsound NS-08e change from 9pin to 7pin?


Hashi8888 said:


> Did Nobsound NS-08e change from 9pin to 7pin?


Yes, in 2018 I think. Old version - 9 pin, new version - 7 pin. It has been discussed here, unfortunately sometimes you have to read the whole thread, not just 1 old post.


----------



## alexbau

It's been said a few pages before, anyway there's someone who knows some tube to substitute the chinese which comes with the Nob?


----------



## YanaMJ

Hello,

I'm forecasting to buy this little amps and to change the tubes. I'd like to use it with a Kennerton Vali and a Meze 99 Classics combined with an Ibasso DX160. Do you think it is worth a try ?

Thanks a lot for your help.


----------



## Arro

I've been experimenting with both versions of the amp. So far I've found a fully compatible tube that I haven't seen mentioned yet. The 6J49P is an improved version of the 6J9P. It's also available in E, D, DR and DRY variants from the Reflector and Ryazan factories. The 6J49P is a B9A socket tube and will only work in the 6J9 version.


----------



## RickeyM (Dec 10, 2020)

I've been enjoying my Nobsound NS-08E for a couple of years now. I have some GE 6J4 tubes in place of the originals and I swapped out the original Op-amps for some LM4562's. Outstanding sounding amp for the price. I had some High Current Output Low Distortion Dual Op-amps I got for my disc player but haven't gotten around to using them so I thought why not try them in my "Nobby"? The result? _Niiice _ Subjectively speaking they give more depth, definition and a bit better dynamics. It's impossible to do a quick A-B comparison but I've been listening with the LM4562's in there for a couple of years and I do like the discrete Op-amps a bit better. For about $16 bucks I recommend them. I have no idea whether they're better than something like the Burson discrete Op-amps but IMO they're better than the LM4562's which in turn are better than the stock Op-amps. The only bummer is having to wait around four weeks or so to get them. I call it a nice plug in upgrade.


----------



## donato (Jan 23, 2021)

I had this nobsound in my office setup with a dragonfly red, but I had switched to being remote well before the pandemic so this was just sitting in storage in my garage at home.  I just happened to stumble on to it again so I hooked it up again.  I had upgraded tubes to Amperex 6688 which made a huge difference in sound (love the soundstaging and a fun midbass bump (it was the tracks I was listening too).  this has got to be one of the cheapest platforms to do tube rolling).  Currently listening with my LCD-1.  In any case, I rediscovered the fun with this little setup.  Rolling op amps also sounds like something fun to try too.


----------



## MisterMudd

donato said:


> I had this nobsound in my office setup with a dragonfly red, but I had switched to being remote well before the pandemic so this was just sitting in storage in my garage at home.  I just happened to stumble on to it again so I hooked it up again.  I had upgraded tubes to Amperex 6688 which made a huge difference in sound (love the soundstaging and a fun midbass bump.  this has got to be one of the cheapest platforms to do tube rolling).  Currently listening with my LCD-1.  In any case, I rediscovered the fun with this little setup.  Rolling op amps also sounds like something fun to try too.


Dang it. Just boxed mine up in favor of my new iFi Zen. Maybe pull it back out too!! LOL. Only reason I boxed it up was for desk space.


----------



## donato (Jan 23, 2021)

I'm still reading through the entirety of this thread, but where is a good place to buy alternate op amps?

EDIT: Never mind.  I found them on digikey


----------



## donato

I had tried a couple different opamps from digikey, the LM4562NA ($1.74 each) and the OPA2134PA ($5.08 each).  Both were an improvement over the stock NE5532.  I settled on the OPA2134PA with Amperex tubes.  But I just swapped in the Burson V5i ($79/pair) and that totally blew away the OPA2134PA.  It brought a bit more mid presence, but more importantly it significantly cleaned up the bass which would sometimes get a bit bloated/muddy.  I also received some Mullards so I'll to give those a roll to compare to the Amperex.


----------



## MisterMudd

donato said:


> I had tried a couple different opamps from digikey, the LM4562NA ($1.74 each) and the OPA2134PA ($5.08 each).  Both were an improvement over the stock NE5532.  I settled on the OPA2134PA with Amperex tubes.  But I just swapped in the Burson V5i ($79/pair) and that totally blew away the OPA2134PA.  It brought a bit more mid presence, but more importantly it significantly cleaned up the bass which would sometimes get a bit bloated/muddy.  I also received some Mullards so I'll to give those a roll to compare to the Amperex.


Thanks for the rolling. Very interesting. May open mine up now.


----------



## donato

MisterMudd said:


> Thanks for the rolling. Very interesting. May open mine up now.


If you haven't upgraded the opamp, definitely worth it.  I've also ordered a pair of Sparkos SS3601 based on a recommendation.  About the same price as the Burson though.

The Mullards so far have been great.  Probably my favorite.  Had to retry all my tubes after the opamp change.  I have GE JAN, Amperex, and Mullard.


----------



## Minipeace

Hello, I’ve just purchased this little amp and I’m looking into changing the amps to the Burson V5i. 
I noticed there are 2 models a dual and single and looking the the original amp it’s a dual but I just wanted to double check it’s the dual channel V5i that would be the direct replacement.
Thanks.


----------



## donato

Minipeace said:


> Hello, I’ve just purchased this little amp and I’m looking into changing the amps to the Burson V5i.
> I noticed there are 2 models a dual and single and looking the the original amp it’s a dual but I just wanted to double check it’s the dual channel V5i that would be the direct replacement.
> Thanks.


The dual is what I replaced mine with.


----------



## Minipeace

donato said:


> The dual is what I replaced mine with.


That’s great, thanks for putting my mind at rest. Off I go to order a pair.


----------



## donato

Minipeace said:


> That’s great, thanks for putting my mind at rest. Off I go to order a pair.


Report back what you think!


----------



## Minipeace

donato said:


> Report back what you think!


Will do. I’ve also ordered a pair of Russian 6J3P to change out the ones supplied. I’m a Valve novice 😊 the closet to valves in my current speaker setup is the Musical Fidelity A370.2 where Tim de Paravicini (EAR) was involved in some of the design work of this massive solid state amp and with great sadness is no longer with us.

The amp is up and running while I wait for all the items to arrive and I’m using my HD660S. Will be interesting to see what difference the amps make then I’ll swap the valves and have a listen. 

​


----------



## Minipeace

Ok I’ve had a while with the amp and I suppose this is all objective but as it stands with no modifications I find it’s a tad grainy or course up in the top end and a bit congested overall. It’s not bad but that’s the traits I’m finding but in a way there is a fluid or a more open type sound which I like. 
Reading the thread I hope the change of tubes and the opamps bring a more detailed sound but keep the open type sound. It’s an interesting little amp for sure.


----------



## donato

Minipeace said:


> Ok I’ve had a while with the amp and I suppose this is all objective but as it stands with no modifications I find it’s a tad grainy or course up in the top end and a bit congested overall. It’s not bad but that’s the traits I’m finding but in a way there is a fluid or a more open type sound which I like.
> Reading the thread I hope the change of tubes and the opamps bring a more detailed sound but keep the open type sound. It’s an interesting little amp for sure.


In stock form, the sound is compromised.  The burson opamps make a substantial improvement and tubes can as well.  I'd recommend the mullards or amperex


----------



## alexbau

on which tube setup? the 7 pins or the 9? 9 is the old one, the newest Nobsound comes with 7 pins tubes... are Mullard and Amperex 7 pins? what are the codes? thanks


----------



## Minipeace (Mar 19, 2021)

I don’t believe they are but I could be wrong. Mines the 7 pin version so I need to look around for more valves.
I’ve just received the Russian valves and just trying them now. First impressions are it’s cleaner sounding. Need a bit of listening but so far so good. just need the opamps now.

Edit. Spent the afternoon having a nice long session relaxing and its quite a difference with the swap of valves. Gone has the harshness or grainy texture in the highs and overall a cleaner sound which helps the separation of instruments. I’m really hoping the opamps can add more detail but for a cheap little amp I’m pleasantly surprised.


----------



## donato

alexbau said:


> on which tube setup? the 7 pins or the 9? 9 is the old one, the newest Nobsound comes with 7 pins tubes... are Mullard and Amperex 7 pins? what are the codes? thanks



I have the older 9 pin and the mullard and amperex tubes I was referring to were 9 pins of course.  Not sure what's available for the 7-pin tube.


----------



## alexbau

Minipeace said:


> I don’t believe they are but I could be wrong. Mines the 7 pin version so I need to look around for more valves.
> I’ve just received the Russian valves and just trying them now. First impressions are it’s cleaner sounding. Need a bit of listening but so far so good. just need the opamps now.
> 
> Edit. Spent the afternoon having a nice long session relaxing and its quite a difference with the swap of valves. Gone has the harshness or grainy texture in the highs and overall a cleaner sound which helps the separation of instruments. I’m really hoping the opamps can add more detail but for a cheap little amp I’m pleasantly surprised.



Hi Minipeace, could you please tell us what to search for this Russian tubes? I'm searching too for 7 pins tubes... thanks!!


----------



## alexbau

donato said:


> I have the older 9 pin and the mullard and amperex tubes I was referring to were 9 pins of course.  Not sure what's available for the 7-pin tube.



It seemed to me, 'cause many says that the new version (7 pins) sounds better than the 9 pins and I'd like to know if tube rolling and Burson's opamp could still be a good change (for the bucks).


----------



## Minipeace

alexbau said:


> Hi Minipeace, could you please tell us what to search for this Russian tubes? I'm searching too for 7 pins tubes... thanks!!


hope this helps.
https://www.audiozomba.com/product/nobsound-amplifier-vacuum-tubes/

i purchased the Russian valves here and they come as a pair. I’m a complete novice with valves so it seemed a safe choice.

Im still waiting for the opamps to arrive to give them a try.


----------



## alexbau

Thank you Minipeace, I-ll take a look! Please let us know when Bursons will be in place!


----------



## donato

I also have the Sparkos opamps coming so i'll give that a try too in addition to the Burson v5i.  I debated even trying some of the higher end Burson's just for the hell of it although I wouldn't be able to keep the case on.


----------



## donato

Minipeace said:


> hope this helps.
> https://www.audiozomba.com/product/nobsound-amplifier-vacuum-tubes/
> 
> i purchased the Russian valves here and they come as a pair. I’m a complete novice with valves so it seemed a safe choice.
> ...



Yes, this has to be one of the cheapest/easiest devices to do some valve/tube rolling as well as opamp rolling.  I had never done opamp rolling before this unit.  It's good cheap fun for sure.


----------



## Minipeace

donato said:


> Yes, this has to be one of the cheapest/easiest devices to do some valve/tube rolling as well as opamp rolling.  I had never done opamp rolling before this unit.  It's good cheap fun for sure.


The V5i set has arrived and I’ve just pushed them in and am listening to them now.
first impressions are It’s cleared up the low end and listening to Frank Zappa Bobby brown goes down his voice has a darker lower level. 
Hazel O’Connor will you shows the high end has a nice sharp finish with the T and S sounds no longer sounding harsh. 
Kate Bush Cloudbusting her voice has the lovely Ts and very sharp sounding. 
Overall it’s cleaner sounding, more depth and a better soundstage. Will be interesting to see if it changes over the run in period the Bursons talk about.


----------



## donato

I finally got around to replacing the Bursons with the Sparkos.  Initial impressions are that these are even cleaner sounding than the Bursons (which in turn were better than the handful other opamps I had tried).  Bass seems much better, cleaned up and less muddy.  It's sounding really great, but I do need to do a more thorough comparison with the Burson.  Then again, these Sparkos cost about double what the Burson cost.  I'd be interested in trying the more expensive Bursons too, but then the case wouldn't fit anymore.  Still using the Mullards, but I may have to give the Amperex another try too.


----------



## donato

Swapping between Amperex and Mullard, Mullards have slightly better bass control, Amperex are a little more and much more spacious sounding.  So pick your tradeoff.


----------



## alexbau

donato said:


> I finally got around to replacing the Bursons with the Sparkos.  Initial impressions are that these are even cleaner sounding than the Bursons (which in turn were better than the handful other opamps I had tried).  Bass seems much better, cleaned up and less muddy.  It's sounding really great, but I do need to do a more thorough comparison with the Burson.  Then again, these Sparkos cost about double what the Burson cost.  I'd be interested in trying the more expensive Bursons too, but then the case wouldn't fit anymore.  Still using the Mullards, but I may have to give the Amperex another try too.


Hi Donato, these Sparks seems to be the SS3602 Dual, not the Single one... it is?
- Alex


----------



## donato

alexbau said:


> Hi Donato, these Sparks seems to be the SS3602 Dual, not the Single one... it is?
> - Alex


Yes, those are the dual.  I actually made the initial mistake of order the single and having it not work before exchanging them for the duals (and paying the cost difference of course).


----------



## MisterMudd

Totally agree with @donato that the amp is very easy to roll opamps and, like his, my Nobsound NS-08E is the older 9-pin model from 2015. Have been listening to mostly solid-state DACs and Amps over the last few years, with my NS collecting dust on my desk. Even boxed it up a few times over the years, but this thread has me pulling it back out again, likely to reside bedside now. I’ve only rolled tubes with this amp and my stock includes the Philips E180F (Mullards), Amperex, and GE JAN. Out of those 3 the Mullards are far and away the best of the 3 tubes, and took up permanent residence way back. The others do not come close in my estimation. Recently got the new Burson V5i dual opamps in but spent a good while listening with the original opamps before switching out. What I thought was pretty good with the original opamps took a significant leap upward with the V5i. Quite amazing actually. Listening to a variety of music with Philips Fidelio X2 (OG-2014) and the newer HiFiMan Deva was totally, addictive. The Burson’s bookended the sound extremely well with much better treble and very, very well-done bass. That said, the best compliment I could give the V5i is that they presented a superior balanced sound, nothing overdone, while granting a wider soundstage and more airy presence. The upper end sounded sweeter and more precise, while the mids were brought forward in a smooth complementary fashion. Voices sounded way more natural. The Deva was a pure joy to listen to with this setup. If I was forced to choose one aspect of the improved sound to highlight, it would be the bass! Gone was the pedestrian bass of the original opamps. Man, it just came through so well defined with the Burson it was not even close. The Nobsound NS-08E is an incredible bargain I think, and the Burson V5i for the entry price is an outstanding achievement. This combo is now gonna get a LOT of head time. I may just buy the newer version of the Nobsound NS-08E and pair it with my new Schiit Modi 3+ DAC. Whatever you do – Enjoy the music!!


----------



## donato

MisterMudd said:


> Totally agree with @donato that the amp is very easy to roll opamps and, like his, my Nobsound NS-08E is the older 9-pin model from 2015. Have been listening to mostly solid-state DACs and Amps over the last few years, with my NS collecting dust on my desk. Even boxed it up a few times over the years, but this thread has me pulling it back out again, likely to reside bedside now. I’ve only rolled tubes with this amp and my stock includes the Philips E180F (Mullards), Amperex, and GE JAN. Out of those 3 the Mullards are far and away the best of the 3 tubes, and took up permanent residence way back. The others do not come close in my estimation. Recently got the new Burson V5i dual opamps in but spent a good while listening with the original opamps before switching out. What I thought was pretty good with the original opamps took a significant leap upward with the V5i. Quite amazing actually. Listening to a variety of music with Philips Fidelio X2 (OG-2014) and the newer HiFiMan Deva was totally, addictive. The Burson’s bookended the sound extremely well with much better treble and very, very well-done bass. That said, the best compliment I could give the V5i is that they presented a superior balanced sound, nothing overdone, while granting a wider soundstage and more airy presence. The upper end sounded sweeter and more precise, while the mids were brought forward in a smooth complementary fashion. Voices sounded way more natural. The Deva was a pure joy to listen to with this setup. If I was forced to choose one aspect of the improved sound to highlight, it would be the bass! Gone was the pedestrian bass of the original opamps. Man, it just came through so well defined with the Burson it was not even close. The Nobsound NS-08E is an incredible bargain I think, and the Burson V5i for the entry price is an outstanding achievement. This combo is now gonna get a LOT of head time. I may just buy the newer version of the Nobsound NS-08E and pair it with my new Schiit Modi 3+ DAC. Whatever you do – Enjoy the music!!


What a great writeup and glad you found some great sound.  You definitely get some bang for your buck with this little unit and it's cheap and easy enough to roll tubes and opamps.  I still use mine daily even while still chasing summit-fi sound otherwise.


----------



## Mortus (Jun 15, 2021)

hey guys i am popping my head to let you know there is carbon copy of this amp for 25 eur  on amazon.it it is same as nobsound ns-08e upgraded version with 6j3 7 pin tube link tomorrow i will receive GE JAN 5654w tubes, and around Friday lm4562na op amps ,but even on default my akg k712pro with my merdian explorer 2 as source made me very happy with sound quality it produces , i also think tubes will change sound ,but for op amp im not so sure will it change anything cuz ne 5532 p is already pretty good , i am new to tube stuff did i pick good ones ?which can be considered upgrade over stock tubes ?

Edit:
GE JAN 5654W one thing i can say "vieni vedi vinci" sound is like 2 classes above bass treble separation soundstage all got level up in terms of quality and  quanity i hear now things in records i would not hear before i probably will spend now night hearing my old faithful playlist    , btw i dont know is it important but now when i swaped tubes that  came as default they were mislabeled  they were  not 6j3 tube instead  6j3-j i dont  know if there is difference or they are worse  but i wanted to point it out

i will share my opamp swap latter but  so far i could not swap for lm 49860na because amp after placing second op amp started to buzz so i think there might be some compatibility issue can you suggest me some op amps known to be compatibile with this amp ?


----------



## sfrsfr (Aug 5, 2021)

Nobsound NS-08E was introduced more than 5 years ago and it seems to be still popular.
I am interested to try it out for high impedance earbuds and have a few questions:
1) Is there anything better now in this price category (under $100)?
2) Did anyone directly compare the upgraded version to the original one? I understand only the tubes are different... would any of them be preferable?
3) Would Muses02 opamps be a good match for it (vs Burson V5i)?

Thank you!


----------



## rlisin

sfrsfr said:


> 2) Did anyone directly compare the upgraded version to the original one? I understand only the tubes are different... would any of them be preferable?


I did - sort of. I had to go by memory because my original version already had stock tubes replaced with Russian ones and I had to rely on my memory comparing it to my friend's revised version with stock tubes. My impression was that they were similar with stock tubes: not bad, but definite room for improvement in terms of clarity, bass and treble extension etc. Both improved immensely after replacing stock tubes with Russian NOS ones. There were very minor differences between them, but those could be attributed to the tubes and since the two amp versions use different tubes, there is no way of comparing the devices themselves, with tubes taken out of the equation. I would say you're good with either version of the amp.

We bought each amp for around $30, under $50 including 4 replacement Russian tubes for each amp, and I don't think there's anything better (or even close to that quality) you could get for the money we paid. Considering the combination of SQ and power, I don't see anything that could compete in the price range under $100 either.

We haven't tried different opamps yet.


----------



## athiker94

May have already been mentioned. Read somewhere that they are having good luck with the GE Jan 5654W tubes.


----------



## athiker94 (Mar 9, 2022)

Do the GE 5654 tubes need burn in? I just put them in over the last few days and they SEEM a dot harsh. I like the original tubes a dot more in their musicality at this point. But, the sound is way more refined and balanced with the new tubes. Just a bit harsh at times.

EDIT: the tubes sound better now and this little amp sounds amazing with my He400i phones.


----------



## DaddiPig (Jul 28, 2022)

athiker94 said:


> May have already been mentioned. Read somewhere that they are having good luck with the GE Jan 5654W tubes.


I know this is old but I thought I just had to comment on this. I just got the DollaTek Jan 5654W tubes for this little amp and the difference is nothing short of amazing. It's like night and day. The high end is now so much crisper and ride cymbals etc are no longer a faint "ding" in the background they come through crystal clear with the resonance they should have (I used to be a professional drummer so I know how they should sound). The whole frequency range is much more natural with cleaner bass and mid range and extended high end. There is now a presence to the music that just wasn't there with the stock tubes. I have the later model which came with the 7-pin 6J3s. These Jan 5654W tubes have totally transformed this amp and anyone that owns this little gem should without a doubt change the stock ones, you won't regret it and at £13.99 GBP for a matched pair it's a no brainer!


----------



## AndreRitter

I have scored one of these for thirty quid delivered. 
While I eagerly await said delivery I have the odd question or three.
Anybody done much modding to these? I'm obviously going to have to lose the blue LEDs and I'm going to look at changing the 3.5mm sockets but I wonder what else has been tried beyond those and rolling tubes and op-amps?
Is the 5654 really a swap for 6j3? I loved the 5654 sound in a full size power amp some years ago so it's a lovely thought.
I have no doubt I shall be back with more questions or at least some images of mods in progress.
Cheers all, here's to a great day.


----------



## AndreRitter

Had a look at The Valve Museum and the specs for EF95 (5654) and EF96 (6J3) are very close so I now have an even bigger monkey on my back.
http://www.r-type.org/exhib/aaa0409.htm
http://www.r-type.org/exhib/aaa0122.htm


----------



## DaddiPig (Oct 22, 2022)

AndreRitter said:


> I have scored one of these for thirty quid delivered.
> While I eagerly await said delivery I have the odd question or three.
> Anybody done much modding to these? I'm obviously going to have to lose the blue LEDs and I'm going to look at changing the 3.5mm sockets but I wonder what else has been tried beyond those and rolling tubes and op-amps?
> Is the 5654 really a swap for 6j3? I loved the 5654 sound in a full size power amp some years ago so it's a lovely thought.
> ...


Hi Andre. Please see my post above. I got the DollaTek Jan 5654W tubes from Amazon and it has made a world of difference as per my post. I see they are still available and at that price it really is worth giving them a try. I'm going to try swapping out the op amps too at some point but I haven't got round to it yet as its not my main amp (I have a Stax setup which I use most of the time and also a Musical Fidelity M1 HPAP for dynamic cans) but I have heard it can make quite an improvement. I have used the NS-08E with AKG K712 Pro and Beyer Dynamic DT990 Pro 250 ohm version and it drives both easily and sounds surprisingly good with both. Its a great little amp for no money and quite powerful (I believe its 1.1W into 32 ohm) so will drive most cans easily. Have fun!


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## AndreRitter

That's the Jan sound in my experience too china.
I used to alternate a set of Jan with another of Brimar in the pre section of a Chinese integrated.
The joy of tubes, change the sound to suit your mood.


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## finubi (Oct 22, 2022)

I still do not understand, the sound is not amplified by the tubes. Nevertheless, a change can improve the sound? What is the explanation for this?
Which are the best to use with the newer version?


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## RickeyM

Understand the science I do not. Believing what my ears hear I do.


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## AndreRitter

Not impressed.
If anyone is interested mine is on ebay with its original valves and a russian pair with an hour on them.
It is also minus those silly blue leds.


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