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Recommend me a warm, smooth sounding 6922, 6DJ8, ECC88 or equivalent

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I've just built a tube-buffered chip amp, and need to buy a new 6922 or equivalent to use in it. The design I followed is here http://www.customanalogue.com/diytubegainclone/index.htm .

I'll be buying off eBay - I live in New Zealand, and this seems to be the best way to get a wide range of tubes.

I'd like to get one that sounds nice and warm and smooth, if possible.

Are there any particular brands or types that would suit me best?

If anyone has any opinions on whether the design I chose was a good choice when my goal is warm, smooth sound, I'd be interested to know this too.

Thanks heaps :)
 
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gaplessophile said:
I've just built a tube-buffered chip amp, and need to buy a new 6922 or equivalent to use in it.
...
I'd like to get one that sounds nice and warm and smooth... .

At the risk of offending you (and any other sentiment-driven lurkers) I will tell you the truth: a vacuum tube does not have a sound quality, and hence you can not seek one that has a "nice and warm and smooth" sound.

Instead they have electrical characteristics that the designer selects and must manipulate by way of the surrounding circuitry in order to influence the overall sound quality of the system.

The notion that there are tubes which sound warm, or harsh, or accurate, or smooth, etc., is just nonsense spoken by people who want to sound as if they understand the subject, or who want to be seen as experts to boost their own ego, or they want to sell you something.

The tube in the linked schematic is an impedance converter - it presents a high impedance at the input so as to not load down the source, and creates a low(-ish) impedance at its output to drive the chipamp. I am surprised that the chipamp needs this impedance converter ( / buffer). The tube in this configuration will reduce the size of the input signal a little (which is a fact, but it may not be important), and it will introduce a little distortion. You may in fact like that type of distortion or you may not even notice it.

If you are very lucky the tube specification and the opperating point set by the designer (via the surrounding components) may contribute towards a sound that you interpret as 'warm and smooth'. Let's hope so.
 
What Grody said! And I could not have said it better myself. I have always believed that a tube has no characteristic sound of it's own, so long as it was "good" and not too microphonic or noisy. Why would a stream of electrons in one tube sound different from another? Seems logical, yes? But there's one small problem.

I'm not a hyper-sensitive listener (thank God) like some people I know from the NJ Audio Society I belong to. But even in my mid 60's I can detect subtle differences between certain like number tubes. Almost always small signal and preamp stages. I don't know exactly why this is, but I can hear it. Maybe it's psycho-acoustical or metaphysical to some extent. But it's there. I think this is what gaplessophile is refering to. The fact that in a given fixed circuit different tubes, of the same type, may sound slightly different.

There is no definitive way to predict what tubes will sound good to your personal ear/brain system. I would suggest to gaplessophile that he obtain an assortment to experiment with. I know this is not what he wanted, but there is no correct answer. Only rough guide lines based on one's personal taste. So I'll give you mine.

I prefer European NOS like Amperex, Mullard, Siemens and Telefunken to name a few. The Amperex "Premium Quality" 7308 w/gold pins is one of my favorites. Also, American Sylvania "gold brand" and GE "five star" are premium grades built for low noise. I have no experience with Chinese or Russian tubes. Don't need them, don't want them and don't like them for various reasons. But they are cheap and plentiful so you might want to try some if you can live with their faults. (miss-matched sections & OOT specs.)
 
While I agree with the core of what Gordy and HS are saying, I think that is a great oversimplification and maybe not too clear to the original poster? How the characteristics of a brand and type of tube sound is, as you stated, completely dependent on the circuit in question.

As Gordy stated, in that circuit the tube has no gain and so will introduce little if any of the even-order distortion you might be after. I also don't see the point of using a tube there other than for the sake of having a tube somewhere.
 
Load it on SVCS if you want to find the best sweet spot for any tube; then vary plate voltage and cathode resistance in order to find it. It is usually wide enough allowing a huge swing of an output signal.

Any tube has it, but some on very low currents, some on very high currents, but some don't have it because it would be needed to bias it's grid positively, also some need too high voltage for their sweet spot so it is not practical.

All 6922, 6DJ8, ECC88, 6N23P and others has sweet spots on approximately the same voltages and currents.

However, if you want to swap the tube in some particular design you have to guess what tubes better fit in conditions predefined by the developer that most usually used databooks and datasheets for particular tubes. No one can help you there.

For the design on the link also nobody can help you because 100% feedback in cathode follower eliminates all differences. Probably, the right answer is, "Buy a healthy one"
 
Many thanks for all your responses!

Please forgive my lack of knowledge about tubes - your advice has hopefully set me on track :)

That's interesting that the tube needs to be providing some sort of voltage gain in order to "colour" the sound much - maybe I didn't pick the most appropriate design after all.

I guess I'll just get a tube and find out :)
 
Hi gaplessophile,

In terms of modern production (ie easiest for you to obtain) it's not looking too bad. The current JJ brand was surprisingly pleasant to my ears. Even the Sovtek 6922 isn't too harsh (although it's rather mind-numbingly boring and 'oppressive' sounding for music playback). There are new entrants all the time and there may now be something out now that's better than the JJ, but I can't say since havn't had any cause to seek out a replacement set yet

As for the makes of yore: Mullard, Amperex, and Philips 'SQ' have tended to be my own preferences matching the kind of sonics you seek. Siemens (also rebranded by RCA) tend to be a little more extended in the highs, but still manage a pretty liquid & grain-free presentation.
Any of the aforementioned would tend to cost 3 to 4 times more $'s than a JJ, however.
 
Something to be aware of, the 6922 family is quite prone to instability - which will manifest as harsh brittle sound. So very careful attention to layout with grid stoppers and the anode load right on the pin, will eliminate this as an issue.

I built that circuit a long time ago- watch for large amounts of DC on the output at power up (I fried some vintage speakers with this buffer). Also be aware that this is a very much simplified version of the commercial version offered elsewhere on the sight, and the sound quality to be expected is not what is possible.

Shoog
 
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Joined 2006
Re: Re: Recommend me a warm, smooth sounding 6922, 6DJ8, ECC88 or equivalent

Gordy said:


At the risk of offending you (and any other sentiment-driven lurkers) I will tell you the truth: a vacuum tube does not have a sound quality, and hence you can not seek one that has a "nice and warm and smooth" sound.

Instead they have electrical characteristics that the designer selects and must manipulate by way of the surrounding circuitry in order to influence the overall sound quality of the system.

The notion that there are tubes which sound warm, or harsh, or accurate, or smooth, etc., is just nonsense spoken by people who want to sound as if they understand the subject, or who want to be seen as experts to boost their own ego, or they want to sell you something.



Majestic said:

...
In terms of modern production (ie easiest for you to obtain) it's not looking too bad. The current JJ brand was surprisingly pleasant to my ears. Even the Sovtek 6922 isn't too harsh (although it's rather mind-numbingly boring and 'oppressive' sounding for music playback).
...
As for the makes of yore: Mullard, Amperex, and Philips 'SQ' have tended to be my own preferences matching the kind of sonics you seek. Siemens (also rebranded by RCA) tend to be a little more extended in the highs, but still manage a pretty liquid & grain-free presentation.
...


EXCUSE ME. WHICH PART OF... "a vacuum tube does not have a sound quality... Instead they have electrical characteristics that the designer selects and must manipulate by way of the surrounding circuitry in order to influence the overall sound quality of the system." ...DID YOU NOT UNDERSTAND?

I offer you a FACT, yet you still insist on some namby-pamby, sentiment-driven, emotional drama-queen audiophile nonsense?

May I suggest AudioAsylum.com for your emotional needs.

And while I have your attention let me give you a couple of hints:

1.
JJ, Mullard, Philips, etc., produced hundreds of thousands of each type of tube. For you, or any 'audiophile', to draw a conclusion from sampling only a few (or maybe just a pair) from such a vast number is complete nonsense.

2.
There is one main specification for each tube, and everything else you hear (...in an otherwise equivalent circuit ...) is down to TOLERANCES. Some were pretty decent at 10%, while others exceeded 20% or more. That is the difference you are hearing... the tolerances between each individual tube interacting with the circuit... not the difference between manufacturers.


So why the pseudo-rant? Because you have taken a sample of so few from a sea of so many and drawn a sentiment-based conclusion and then offer it as if it is a fact. This is the sort of nonsense that BLIGHTS audio design and promotes further misinformation as non-technical drivel is spread from person to person.

OK, rant done.
Said Gordy, shaking his head, as he wandered off to the pub...
 
EXCUSE ME. WHICH PART OF... "a vacuum tube does not have a sound quality... Instead they have electrical characteristics that the designer selects and must manipulate by way of the surrounding circuitry in order to influence the overall sound quality of the system." ...DID YOU NOT UNDERSTAND? I offer you a FACT, yet you still insist on some namby-pamby, sentiment-driven, emotional drama-queen audiophile nonsense?

Chacun a son gout. You made what I think is the key, valid technical point. No need to get personal insulting with those who don't want to take a technical path.
 
gaplessophile said:
I've just built a tube-buffered chip amp, and need to buy a new 6922 or equivalent to use in it. The design I followed is here http://www.customanalogue.com/diytubegainclone/index.htm .

I'll be buying off eBay - I live in New Zealand, and this seems to be the best way to get a wide range of tubes.

I'd like to get one that sounds nice and warm and smooth, if possible.

Are there any particular brands or types that would suit me best?

If anyone has any opinions on whether the design I chose was a good choice when my goal is warm, smooth sound, I'd be interested to know this too.

Thanks heaps :)

I know the amps designer, Joe Rassmussen, great bloke. Changing
tube types will affect the sound.

Amperex Bugle Boy 6DJ8 large getter is a good choice for this amp.

cheers

Terry
 
6922 equivalent

While I used to use 6DJ8/6922/ECC88 tubes in the past, I've come to find their sound too "hard" and sometimes edgy. However, I've found that the Russian 6N1P, which is fairly close in characteristics, has a much better, more natural sound. The only possible problem is that it's heater current is 0.6A, which is nearly twice that of the 6DJ8. This rules out its use in many commercial preamps, such as the Audio Research, but in home-built equipment, the higher current can easily be accommodated.

I've found that the 6N1P is in general pretty quiet, although, as with all tubes, some selection is needed to find the quietest. One big advantage is that any microphonics that exist are of the "clunky" type of sound, rather than the very high-pitched "zingy" sound found in the frame-grid tubes, such as the 6DJ8. The 6N1P is readily available from the various ex-Soviet block ebay sellers. There is a ruggedized, extended-life version called the 6N1P-EV, but I haven't found it to sound much different than the regular 6N1P.

- John Atwood
 
In the same circuit different tubes do sound different, just like in the same circuit different transistor brands tend to sound slightly different. Given a fixed circuit the original question is valid. If you have the minimal expertise it would be possible to tune the sound of the circuit to your tastes by altering the circuit values, regardless of valve. If the questioner is not confident then a bit of tube rolling is appropriate.
As an example I once had the Musical fidelity X10D tube buffer. I thought I would try a bit of tube rolling to sweeten up the sound. I substituted some NOS Mullard ECC88's. To my inexperienced surprise it sounded horribly bloated and syrupy. I sold the X10D shortly after. It turned out the generic new production no label tubes it was sold with sounded far superior in this particular circuit (they were very nice neutral sounding valves in general). Turned out the circuit was tuned to specifically get the best out of these valves, and MF were correct in recommending only replacing with the same.

The simple inclusion of a 50K trim pots and a series 50K resistor, in parallel with the cathode resistor would work. A series trim pot of say 5k before the final power supply cap would allow tuning of the anode voltage. Simple and might save spending stupid money on one of the most expensive NOS valves out there.

As to harshness from the 6922, I never found it in my Super Linear Cathode Follower preamp (the grandaddy of this tube buffer), but I tuned it out with appropriate circuit changes. I could get it sounding anywhere from full and chunky, to thin and all the way to lush and smooth.

Shoog
 
Re: Re: Re: Recommend me a warm, smooth sounding 6922, 6DJ8, ECC88 or equivalent

Shoog said:
Something to be aware of, the 6922 family is quite prone to instability - which will manifest as harsh brittle sound. So very careful attention to layout with grid stoppers and the anode load right on the pin, will eliminate this as an issue.


A very good reminder, shoog. Everyone take note.


Gordy said:

EXCUSE ME. WHICH PART OF... "a vacuum tube does not have a sound quality... Instead they have electrical characteristics that the designer selects and must manipulate by way of the surrounding circuitry in order to influence the overall sound quality of the system." ...DID YOU NOT UNDERSTAND?

I understood all of what you were saying. That is the way things should operate in the real world.

The trouble is that's not the case. Most tubes do have a sound. One that follows the tube when it is replaced in different equipment. I don't like it any more than you do (though it's actually nice to be able to have an extra degree of sonic control [over and above the circuit] by changing said parts.)


Gordy said:

I offer you a FACT, yet you still insist on some namby-pamby, sentiment-driven, emotional drama-queen audiophile nonsense?
Yes I still insist because I'm also trying to offer you and others a fact based on experience. Both personal and that of others too who have also heard the same thing.

Judging by the firmness of your insistence I suspect that your position on this is already cast in stone and will thus not be well-received by you. Perhaps just look at the L-plates on my avatar and just put it down to starry-eyed electrical inexperience if that makes it easier.

...or maybe just have another beer! :clown:


Gordy said:

May I suggest AudioAsylum.com for your emotional needs.

I tend to listen to music for my emotional needs atm.

Gordy said:

And while I have your attention let me give you a couple of hints:

1.
JJ, Mullard, Philips, etc., produced hundreds of thousands of each type of tube. For you, or any 'audiophile', to draw a conclusion from sampling only a few (or maybe just a pair) from such a vast number is complete nonsense.

I wasn't saying that all Mullards have a definite sonic quality. I was talking about their ECC88's. And yes the circuit matters as shoog noted above.

Gordy said:

2.
There is one main specification for each tube, and everything else you hear (...in an otherwise equivalent circuit ...) is down to TOLERANCES. Some were pretty decent at 10%, while others exceeded 20% or more. That is the difference you are hearing... the tolerances between each individual tube interacting with the circuit... not the difference between manufacturers.
That sounds like decree of sound-quality by proclamation. Perhaps you could cast your magic over some remaining quibbles in my Hi-Fi system?

I've tried probably over 20 different makes of 6DJ8's & 6922's in my time. They all had an individual sonic character which followed them around even in different circuits.
I'm sorry if this does not agree with your outlook of the electronic domain, but it seems to be an unfortunate reality; and not just for myself, but tens of thousands of music lovers globally.
 
EXCUSE ME. WHICH PART OF... "a vacuum tube does not have a sound quality... Instead they have electrical characteristics that the designer selects and must manipulate by way of the surrounding circuitry in order to influence the overall sound quality of the system." ...DID YOU NOT UNDERSTAND?

I offer you a FACT, yet you still insist on some namby-pamby, sentiment-driven, emotional drama-queen audiophile nonsense?

In all fairness, this is not really science but polemic. There are plenty of different ways a vacuum tube can affect a signal not taken into account by the designer and in fact the same tube made by different manufacturers at different times can and will sound different from one another. Bright, smooth, warm, nasty, liquid, harsh, etc. are all legitimate terms one can use to describe the sound of a particular tube.

John
 
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Joined 2006
Re: Re: Re: Re: Recommend me a warm, smooth sounding 6922, 6DJ8, ECC88 or equivalent

JohnAtwood said:
...6DJ8/6922/ECC88 tubes ... I've come to find their sound too "hard"...

(I snipped your post for clarity while trying to retain the core message).

Essentially what you are saying is that every 6DJ8/6922/ECC88, in every possible circuit (...irrespective of anode voltage, current, bias point, psu ripple and load...), in every possible system, sounds too "hard". Any reasonable engineer will find that complete nonsense, and as a 'consultant' you should know better than to suggest it.


Majestic said:

Most tubes do have a sound.


NO, they do not. Systems have a sound.

Systems have a sound, of which the tube is just one contributing part. If you swap a new tube for a similar type of new tube (eg 6DJ8 for 6DJ8) and the sound changes then you are hearing the system response to the difference in tolerance between the tubes. You are not hearing the difference between Mullard and Philips, etc.



Majestic said:
but tens of thousands of music lovers globally.


You will not like the reality of it, but the answer is that it is psychological bias and desire. Yes, really. Many people fall for the charm of the little glowing bottles, and they want to talk about it passionately. But most are not technical and very few can be bothered to learn about impedances, plate curves, etc., etc.. So what do they do? They grab on to whatever sentiment they can, and gush on and on about that. I've seen and heard soooo many of them. They prattle on about 12AX7s that sound cold, 300Bs that are warm and lush, 6H30s that are stout and authoritative... the world is full of these people who draw conclusions from a sample of one and assign sentiment to technology so they can get an involvement with a subject that they can not be bothered to learn properly. That is all well and good if you want to cuddle up to a fellow audiophile and gush merrily, but it has absolutely no place in systems engineering, which is what music reproduction actually is.

.........................

Look, all I was trying to do was point out the fact that if you want to improve your system you need to start understanding the underlying technology, and then point you towards tube specification as a good starting point. But if all you want is to think that individual tubes have a specific sound quality (and believe that it must be right because lots of others say so) then I am wasting my time. Likewise you too are wasting your time because a technical forum is no place for sentiment-driven opinion. (And what happens when six guys say that Mullards sound great and then a half-dozen say that they sound very harsh and hard? Where does opinion get you? There is no true point of reference and you are back to where you started !) Best advice: LEARN THE UNDERLYING TECHNOLOGY AND LEAVE THE SENTIMENT BEHIND.

.............................

Oh why do I bother? I give up. If you want to think that all tubes have a certain sound then get on with it. Good luck. Bye-bye thread.
 
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