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Steve O'Conner wrote; "It isn't clear how much of the sonic signature is a function of the tube, and how much is a function of the supporting circuitry, except I think the answer is "The tube matters somewhat less, and the circuit more, than the Internet would have you believe"."
I couldn't agree more. It's a very difficult situation to asses because there are variables at every turn, a typical 6V6 amp runs 100v more on the plates that a typical EL84 amp. The EL84 PT will need to have a higher heater current capacity, which will have a knock on effect in current draw on the secondaries across the board. If you run 5881/6L6/EL34 at the limit of their plate voltage, that's only going to be moderate plate voltage for 6550/KT88.
Any 6L6 based amp I have built is overengineered in the heater capacity, so that I can run JJ6V6, 6L6/5881/KT66/EL34/6550/KT88/KT90 of the tubes I have tried, a specific brand of a specific model might exhibit unique characteristics, all else being equal (apart from a rebias, of course), but a Bassman fitted with 6550, or EL34 still sounds like a bassman, not perhaps like a bassman with New Jersey Tung Sols, but then neither will that same bassman with Shuguang 6L6GC, or JJ6L6GC, or SED 6L6GC...it sounds like a 50W push pull, fixed bias 4x10" amp, you would have to be VERY familiar with the amp in question, your instrument and the tubes in question to really be able to have half a chance of identifying tube type (within reason). An amp you are not familiar with...? A studio recording where dB/stage volume isn't relevant? Very, very hard to tell tube type...all bets are off as far as I'm concerned (if you just built one model of amp, blueprinted each one, and were familiar with every tube type, you might pick out a few combinations after a few listens and the chance to audition each one).
I'm certainly not saying they all sound the same, nor am I saying that anyone who expresses a specific preference has "golden ears", finding 2 amps of a similar model that sound "the same" is hard enough, but get a dozen similar (same model, but typical manufacturing tolerances) together, with different brands 6L6 type power tubes, fit one with EL34 and the EL34 one probably won't be identified until someone looks in the back. Yes, certain brands have a unique/distinctive character, but you would fine as broad a variation between various 6L6GC types as between some EL34 & some 6L6 types. Caveat - when I say "6L6 types" I am referring to a new, or NOS, tube supplied in a box with "6L6/5881" on the outside, I am not making a distinction between 6L6s "real" or "imagined/based on a ComBlock military octal tube that has a reasonable impedance match & voltage handling" ;-)
I couldn't agree more. It's a very difficult situation to asses because there are variables at every turn, a typical 6V6 amp runs 100v more on the plates that a typical EL84 amp. The EL84 PT will need to have a higher heater current capacity, which will have a knock on effect in current draw on the secondaries across the board. If you run 5881/6L6/EL34 at the limit of their plate voltage, that's only going to be moderate plate voltage for 6550/KT88.
Any 6L6 based amp I have built is overengineered in the heater capacity, so that I can run JJ6V6, 6L6/5881/KT66/EL34/6550/KT88/KT90 of the tubes I have tried, a specific brand of a specific model might exhibit unique characteristics, all else being equal (apart from a rebias, of course), but a Bassman fitted with 6550, or EL34 still sounds like a bassman, not perhaps like a bassman with New Jersey Tung Sols, but then neither will that same bassman with Shuguang 6L6GC, or JJ6L6GC, or SED 6L6GC...it sounds like a 50W push pull, fixed bias 4x10" amp, you would have to be VERY familiar with the amp in question, your instrument and the tubes in question to really be able to have half a chance of identifying tube type (within reason). An amp you are not familiar with...? A studio recording where dB/stage volume isn't relevant? Very, very hard to tell tube type...all bets are off as far as I'm concerned (if you just built one model of amp, blueprinted each one, and were familiar with every tube type, you might pick out a few combinations after a few listens and the chance to audition each one).
I'm certainly not saying they all sound the same, nor am I saying that anyone who expresses a specific preference has "golden ears", finding 2 amps of a similar model that sound "the same" is hard enough, but get a dozen similar (same model, but typical manufacturing tolerances) together, with different brands 6L6 type power tubes, fit one with EL34 and the EL34 one probably won't be identified until someone looks in the back. Yes, certain brands have a unique/distinctive character, but you would fine as broad a variation between various 6L6GC types as between some EL34 & some 6L6 types. Caveat - when I say "6L6 types" I am referring to a new, or NOS, tube supplied in a box with "6L6/5881" on the outside, I am not making a distinction between 6L6s "real" or "imagined/based on a ComBlock military octal tube that has a reasonable impedance match & voltage handling" ;-)
) and I've tried everything from 6p3s to EL37 at some time or another.
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