So what happens when you overdrive them.....did you note any significant differences there ?.
Dan.
I built few SE amps with 45, 2A3, and 300B. During the last few months, I built my first PP amp and experimented with 807, EL34, KT66, and 6B4G output tubes.
The difference between SE and PP amp is rather significant. Both has it's own advantage. SE is excellent for listening vocals, simple music. The PP is great for powerful, orchestra, rock and rolls. SE can produce very finite details of the recording that PP hardly can match.
I used the same type of output transformer from Lundahl with amorphous core. Therefore, the match was base on the same ground.
Johnny
The difference between SE and PP amp is rather significant. Both has it's own advantage. SE is excellent for listening vocals, simple music. The PP is great for powerful, orchestra, rock and rolls. SE can produce very finite details of the recording that PP hardly can match.
I used the same type of output transformer from Lundahl with amorphous core. Therefore, the match was base on the same ground.
Johnny
Were your PP amps Class A DHT zero negative feedback designs ? otherwise the comparison isn't really valid.
Shoog
My PP employs two 76 tube for amplification and phase splitter then drives the power output tubes. The output tubes has common cathode resistor as per Willamson W5 design. There is no NFB at all and Class A operation. The output tubes are strapped in triode mode.
It is real fair competition.
Johnny
It is real fair competition.
Johnny
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When you carry out some more experiments with 300B's, 45's and 2A3 we can rejoin the comparison - or do you not think that DHT outputs bring anything to the mix ??
Shoog
Shoog
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6A3 is the twin brother of 2A3 that has the very similar structure and characteristics. 6A3 stands out of other tetrode or pentode power tubes. It sounds closer to SE amp but with some character of PP.
My question would have to be - what motivated your choice of output valves for your SE and your PP amps. Why didn't you apply the same care and attention to detail on your PP amps as you obviously did on your SET amps.
The best PP designers (Allen Wrights, Lynn Olsen) never compromised on the choice of output tubes for the flagship designs - and the results reflect this.
Shoog
The best PP designers (Allen Wrights, Lynn Olsen) never compromised on the choice of output tubes for the flagship designs - and the results reflect this.
Shoog
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I use almost same hardware for comparison between tubes in my PP amp. That's how I get my comparison. Anyway, this is only my own test and judgement. It is really good being a DIYer that I could modify my amp to work with various tubes.
Fun fun fun.
Fun fun fun.
Indeed it is fun fun fun and great to be able to DIY.
I think my point is - its not at all straightforward to compare when all things are not equal.
Shoog
I think my point is - its not at all straightforward to compare when all things are not equal.
Shoog
Would you say your own comparison quoted below was fair and honest?
As for the invalid comparison, I see a bunch in yours right out of the gate.
They say little knowledge is more dangerous than lack of it. That's because he / she goes around and spread it.
When you carry out some proper amp listening comparisons, we can rejoin the discussion.
Its my opinion based on my experience and extrapolation from others work. Take from it what you will, but I am unwilling to accept the virtues of SE over PP based on the fan mail of SET builders.
Its easily demonstrable that a Class A PP amp of comparable build quality to a SE has significantly lower overall distortion - you have done nothing to refute that.
Shoog
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You've got it wrong. I wasn't trying to refute that. I asked for some details because I wanted to learn. So far, you haven't posted anything helpful (objective) to the readers. Just bunch of speculations and personal opinion based on subjective listening comparisons.
How about my 300B SE amp, at 1W, 5W, and noise floor. These are not perfect comparisons, it can be argued, but they are not totally subjective, either. Compare 300B SE to 300B PP. I have tried a few different output transformers, and the difference in FFT is minute at best, especially for the SE since it is quite full of harmonic distortion.
Depending on my mood, there are times when I prefer the SE over the PP, but by and large the PP wins the audible contest. For me, measured distortion generally confirms my audible preferences.
Depending on my mood, there are times when I prefer the SE over the PP, but by and large the PP wins the audible contest. For me, measured distortion generally confirms my audible preferences.
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you've shown your 300b SE is relatively clean at 1w and 5w, but not shown how it compares to 300b in PP at 1 w and 5w. or to make it a fair fight, compared to 300b PP at 2w and 10w.
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