Tube Characterization: 6DJ8, 6922, 7308, CCa, etc

Thanks for your input Tvad!

My post is offered more as a contribution and less as a quest for a personal solution. I propose the creation of a logical methodology for determining the sound of individual tube brands and models. This post was inspired by Joe's Tube Lore and I hope would represent the next logical step.

If we can establish a minimum reference then we benefit the greatest number of people. If I only use my personal system as a reference, I benefit maybe only one or two others.

If it can be said that a tube has a house sound then surely there are characteristics latent to the sound of a particular tube in a given context. I really don't think that context has to be as exacting as -this preamp or that preamp- because we are looking at relative values here. But you do make a good point so let me ask what you feel the minimum reference requirements would be to make valid evaluations. Let's start with the above being used as preamp tubes, and that the participants would decide on reference recordings, and that there would be a reference tube from which comparisons can be made. Do you feel that we would have to be more specific than that for the experiment to have value? Once we establish the above, we can get a consensus on descriptions that are objective and quantifiable.

My post is offered more as a contribution and less as a quest for a personal solution. I propose the creation of a logical methodology for determining the sound of individual tube brands and models. This post was inspired by Joe's Tube Lore and I hope would represent the next logical step.

If we can establish a minimum reference then we benefit the greatest number of people. If I only use my personal system as a reference, I benefit maybe only one or two others.

If it can be said that a tube has a house sound then surely there are characteristics latent to the sound of a particular tube in a given context. I really don't think that context has to be as exacting as -this preamp or that preamp- because we are looking at relative values here. But you do make a good point so let me ask what you feel the minimum reference requirements would be to make valid evaluations. Let's start with the above being used as preamp tubes, and that the participants would decide on reference recordings, and that there would be a reference tube from which comparisons can be made. Do you feel that we would have to be more specific than that for the experiment to have value? Once we establish the above, we can get a consensus on descriptions that are objective and quantifiable.

Perhaps I should follow Dsremer's lead and invest in good wine and forget exotic tubes. Now you may like Chardonnays for reason of their peppery quality and I may dislike them for that same reason. The peppery quality remains.

Tubes too indeed have characteristic sonic qualities as does everything else in the component chain. For instance, in the 6DJ8 family, I have never heard a Telefunken that didn't have soft, warmish sounding bass relative to say a Mullard which I would characterize as quicker cleaner, with more dynamic impact. Then again Teles have those liquid mids and highs. Though you may like what you like and that's how it should be, I doubt any of you that have experience with the afore mentioned tubes would question my objective observations. We need a peoples point of reference and a common objective language.

My system:
Porter Ports (20 amp cryo)
Eichman Express Power
Denon 3910
Synergistic Research Designer Reference Interconnect 1m
DK VS-1 Mk III:
Synergistic Research Alpha Quad Active 4m

Synergistic Research Designer Reference FX Interconnect 4m
NuForce Ref 9s
Synergistic Research Designer Reference Spkr Cable 2m

Von Schweikert VR4 Jrs

I'm using Valvo E188CCs in the DK

If you still think I'm all wet (as opposed to lucid with great midrange sparkle), I'll discontine this thread.

08-01-06: Mrtennis
"this question can only be answered in the context of a particular tube circuit".

08-01-06: Rchau
"You can change the sound of tube by just changing the operating point (plate voltage, load ressistors, heater voltage,...). Also, the sound in different topologies(anode follower, cathode follower, cascade, mu follower, etc..) vary with the same tube".

This is the first issue that needs to be addressed: Can anyone offer confirmation that using the same tube (control) in a number of different preamps radically changes the latent sonic characteristics of that tube or will there remain a distinct signature? It seems to me that a designer creates a tube amp or preamp not because of the electrical characteristics of tubes(you can accomplish that with solid state devices) but rather for some sonic quality inherent with tubes. A tube isn't just another circuit in a device it is "the" circuit in the device and engineers design the ancillary circuits in support of this all important part. I know that I'm out of my depth here but this idea would seem to be supported by Mick Maloney of Supratek and my guess is most other design engineers as well. If indeed your tube component is virtually immune to tube rolling, then it's a moot point. If on the other hand, your sound changes considerably with changes in tubes then you are the most likely candidate for this study.

How, in one breath, can one laud the accomplishment of Joe's Tube Lore and in the next breath invalidate the concept? Let's face it, this classic post has probably generated more tube interest and more tube sales since its release than any other single contribution. Personally, and based on my limited testing of 4 sets of tubes, I have found his objective observations to be spot on and his equipment doesn't even resemble mine. That's why my reaction was, 'hey let's run with this'.

I think Albert Porter is the most generous and one of the most knowlegeable persons in this hobby. I'm hoping that just because his post was in opposition to mine that we're not creating camps. I'd guess that upon the additional information and further reflection, he would incline more towards the "okay if we want to do it, this is what we would have to do" side and this is what I would like to encourage. I'd be very interested to know the vernacular Albert uses in his listening sessions with his friends of invite anyone to recommend such a language, perhaps something used by their favorite reviewer. This could be the Audiogon standard. We can also use existing reviews as a launch point.

You either believe that tubes make a difference or you don't. If they do make a difference, then shouldn't we seek to objectively evaluate and bring closer to science our selection process. than exists currently. Perfect? hardly. Science? sorta. Vauluable? invaluable!

Thanks to everyone who contributed kindly and thoughtfully to this post.

Jab, Cmo, Dopogue, Imin2u, let's move forward. I will repost a part II to this thread in hopes that we can consolidate those of like opinion in this forum. If not I will try to find some other way to invite your participation. I'm planning out a methodology with a speaker designer so when we have a plan of attack I will let you know. Look for: Tube Characterization: 6DJ8 Part II

In the meantime Albert, please feel free to basterdize this thread to your hearts content. The rest of us will be somewhere else. I guess spending an hour on the phone with me discussing audio at 3:00 in the morning was not so much personal generosity as insomnia. Sleep well!

Thanks to everyone who contributed kindly and thoughtfully to this post.

Jab, Cmo, Dopogue, Imin2u, let's move forward. I will repost a part II to this thread in hopes that we can consolidate those of like opinion in this forum. If not I will try to find some other way to invite your participation. I'm planning out a methodology with a speaker designer so when we have a plan of attack I will let you know. Look for: Tube Characterization: 6DJ8 Part II

In the meantime Albert, please feel free to basterdize this thread to your hearts content. The rest of us will be somewhere else. I guess spending an hour on the phone with me discussing audio at 3:00 in the morning was not so much personal generosity as insomnia. Sleep well!

Okay, curiosity got the better of me and I had to see what was going on in this thread. Albert, as you know, I do value your opinion and will no doubt be calling you at some point.

Many of us, certainly tube users, choose sound produced by circuits employing tubes because to us they are different if not preferable to the sound produced by all solid state circuits (with a few notable exceptions). We could call this particular class of sound “the tube phenomena.” We have come to this choice through observation and analysis. My hypothesis is that design engineers employ tubes because of their inherent sonic qualities and not because of electrical parameters that can otherwise be achieved by solid state devices which are cheaper and generally accepted to be more reliable. It would logically follow that these design engineers would want the full measure of benefits that can be derived from the device around which they are basing their design. Wouldn’t you? I know I would. Now you may choose to agree or disagree with my hypothesis but without some conjecture there would be no basis for experimentation. Without experimentation opposing opinions are themselves mere conjecture. Every opposing opinion I have seen in this thread is logical and valid. Does anyone have evidence to support these views? If you do, I would like to investigate whether or not there are certain classes of circuit design (as i suspect there to be) that can be identified by a certain design approach and if “common” designs yield similar sonic results based on a control tube. If we can then name these circuits and identify them within our own equipment, perhaps through consultation with the engineer we would then have a testbed. The idea is to agree upon what we can prove and bring this noble quest closer to fruition for the greatest number of people. If it finally comes to having to share my findings only with other DK Design owners then so be it. Though opinions would seem to lead in that direction, hard indicators do not.

Okay, curiosity got the better of me and I had to see what was going on in this thread. Albert, as you know, I do value your opinion and will no doubt be calling you at some point.

Many of us, certainly tube users, choose sound produced by circuits employing tubes because to us they are different if not preferable to the sound produced by all solid state circuits (with a few notable exceptions). We could call this particular class of sound “the tube phenomena.” We have come to this choice through observation and analysis. My hypothesis is that design engineers employ tubes because of their inherent sonic qualities and not because of electrical parameters that can otherwise be achieved by solid state devices which are cheaper and generally accepted to be more reliable. It would logically follow that these design engineers would want the full measure of benefits that can be derived from the device around which they are basing their design. Wouldn’t you? I know I would. Now you may choose to agree or disagree with my hypothesis but without some conjecture there would be no basis for experimentation. Without experimentation opposing opinions are themselves mere conjecture. Every opposing opinion I have seen in this thread is logical and valid. Does anyone have evidence to support these views? If you do, I would like to investigate whether or not there are certain classes of circuit design (as i suspect there to be) that can be identified by a certain design approach and if “common” designs yield similar sonic results based on a control tube. If we can then name these circuits and identify them within our own equipment, perhaps through consultation with the engineer we would then have a testbed. The idea is to agree upon what we can prove and bring this noble quest closer to fruition for the greatest number of people. If it finally comes to having to share my findings only with other DK Design owners then so be it. Though opinions would seem to lead in that direction, hard indicators do not.

Your responses to this thread, even those in opposition to my ideas are very much appreciated. There is some great information and some true audiophile wisdom here. I've even decided to purchase an integrated for a second system with 6SN7 tubes at the preamp stage.

Though I would concede that there may be no absolute basis for tube selection because of differences in circuitry, there are certainly preamps out there that expose similar qualities in particular tubes. (if my mullard and telefunken tubes sound the same in my preamp as yours, it's probably likely that every other tube will expose similar qualities in my preamp as in yours)

I have come upon a tube that I would like to share with you (with fellow DK owners for sure) that I feel is absolutely amazing and it's a Valvo E188CC. The person who sold it to me claimed it to be a Mullard, but it doesn't look like any other Mullard I have ever seen. The midrange and highs are neutral and transparant and the bass is close to if not the best I've heard. I highly recommend auditioning this tube if you can.

I've continued this discussion on audio asylum on recommendation and have received some quite interesting information there as well. Thanks again for your input.