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


Does anyone agree with me that there should be detailed descriptions of the sonic characteristics of each of the popular versions of each of the above tubes. I've read Joe's Tube Lore and a number of manufacturers web-sites which are great general direction guides but they really don't tell us what we need to know in specific and defined terms. Perhaps starting with an overall sonic characteristic like liquid, or warm, or dry or transparent then their response at the frequency extremes (since this is always an issue with tubes), then perhaps individual characteristis with say female voice, piano etc. and then imaging. We would all purchase a set of cheap base line tubes that are known for consistancy and have clearly defined caharacteristics so that comparisons could be made to this benchmark. Then use benchmark recordings. Even better if we had the same equipment best yet if we benchmarked every component in the chain but not necessary because we would be dealing in relatve values.

Of course there is the question of synergy with existing equipment and the fact that we all don't hear exactly the same and so on and so forth, but again, it would all be relative. "Tube "A" has has better defined bass than the benchmark by a factor of 3 on a scale of 1-10 IMO" for instance. Of course this wouldn't be an exact science but it would give us real direction and be more useful than "this is a really great tube or this is a really, really great tube" or slavishly depending on the opinion of the tube specialty store who may be as honest as the day is long but does have to move what he has in stock. If we can bring this evaluation process closer to science we could spend less time playing this silly expensive guessing games and spend more time exploring the kind of sound we like and buying the kind of sound we want (not to mention, listening to more music) Thoughts?
anacrusis
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Tvad, I suspect that Atmasphere is just supporting his design decisions, thats all. He put his money where his mouth is, but we don't have to. :-)

Interesting thread. For myself rolling tubes is a distraction which keeps me from endlessly spending big bucks on buying, trying, and growing dissatisfied with electonics, wires, PC's, ad infinitum. Just another aspect of the hobby. I try to entertain myself by rolling tubes and playing with room set up. Much cheaper and more fun. To each his own. I can understand why someone would want a near definitive list of tubes, applications, elcetronics speakers, etc, but I think there is a certain amount of mental masturbation involved in thinking that actually accomplishing such a feat was possible. Oh 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.
I suspect that some manufactures choose some particular tubes due to cost, reliabilty, market perception, ease of use, and especially avialability, as well as "inherent sonic qualities".
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