Yes.
Also consider that most "improvements" made from the very start of audio electronics are business motivated.
A PP amplifier is cheaper and lighter to manufacture.
The market wanted things smaller, cheaper, "better".
The cost of manufacturing big iron transitioned to the consumer who shall instead pay to change a larger number of physically smaller tubes.
Compromises are made.
It's not all bad, we all benefit from this progress in our modern lives.
I don't think anybody has made a tube with audio as a top business priority since the 20s or 30s.
This is why these big triodes may be viewed as a pinnacle. They were fashioned around transmitting voice over wire in the nicest sounding way possible.
I mean the Chrysler K-car was also extremely common and popular, it does not make it an ideal platform to build a high performance vehicle. (High performance does not exclusively mean high power)
PP= more watts for less money.
Typically speaking, the higher wattage speaker run with these higher wattage amps may not have been capable of displaying the subtleties between the two topologies.
The race continues today, you can get all kinds of watts for little money.
Not to sound cliche, it's the first few watts that really matter.
Also consider that most "improvements" made from the very start of audio electronics are business motivated.
A PP amplifier is cheaper and lighter to manufacture.
The market wanted things smaller, cheaper, "better".
The cost of manufacturing big iron transitioned to the consumer who shall instead pay to change a larger number of physically smaller tubes.
Compromises are made.
It's not all bad, we all benefit from this progress in our modern lives.
I don't think anybody has made a tube with audio as a top business priority since the 20s or 30s.
This is why these big triodes may be viewed as a pinnacle. They were fashioned around transmitting voice over wire in the nicest sounding way possible.
I mean the Chrysler K-car was also extremely common and popular, it does not make it an ideal platform to build a high performance vehicle. (High performance does not exclusively mean high power)
PP= more watts for less money.
Typically speaking, the higher wattage speaker run with these higher wattage amps may not have been capable of displaying the subtleties between the two topologies.
The race continues today, you can get all kinds of watts for little money.
Not to sound cliche, it's the first few watts that really matter.
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My typical listening levels are made at less than one watt on vintage full range drivers. If there were significant differences in the delivery of the "subtler details" it would be very obvious. The point is the detail comes through whether listening to SE or PP.
These maybe the reasons why there was a general move from SE to PP, but in the terms of this discussion they are largely irrelevant to a comparison between the two in absolute terms. It really goes to confirm my belief that most people have outmoded frames of reference.
Shoog
These maybe the reasons why there was a general move from SE to PP, but in the terms of this discussion they are largely irrelevant to a comparison between the two in absolute terms. It really goes to confirm my belief that most people have outmoded frames of reference.
Shoog
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Run them both well within their linear ability and the comparison is more than fair.
I run my PP and my SE amps at less than one watt almost all of the time. Both are capable of at least double that output (though the PP's is capable of much more).
Don't make silly comparisons of SE at the limits of their ability - but fair comparisons are not difficult to set up.
Shoog
I run my PP and my SE amps at less than one watt almost all of the time. Both are capable of at least double that output (though the PP's is capable of much more).
Don't make silly comparisons of SE at the limits of their ability - but fair comparisons are not difficult to set up.
Shoog
Your previous posts are saying that you don't understand what fair amp comparison is.
I understand well enough that comparing a top flight 300B SET amp against a triode strapped KT88 PP isn't in any way fair.
Driving the PP heavily into distortion just to make a point is another unfair comparison.
Compare like with like, that is 300B SET to 300B PP, both in Pure Class A with ZgNFB, both within their most linear range, and you have a fair comparison.
I really think you are just been a obtuse now in refusing to understand simple straightforward statements. Accusing me of not understanding is very rich here when I have been abundantly clear about what I mean from the start of this discussion - and it has not changed one bit from what I have just bolded.
Shoog
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If you believe your amp listening comparison method quoted below qualifies as understanding well enough, then perhaps you can answer the following question. To what decibel did you match the levels?
OT posts removed. Please keep on topic and refrain from personal remarks.
"It really goes to confirm my belief that most people have outmoded frames of reference. Shoog"
Couldn't agree more. I'm going into 2014 with a PSE amp entirely made up of 4P1L directly heated tubes.
Happy New Year Shoog, Pano and everyone. Happy listening in 2014. Hopefully my greetings are all matched to within one decibel!
Couldn't agree more. I'm going into 2014 with a PSE amp entirely made up of 4P1L directly heated tubes.
Happy New Year Shoog, Pano and everyone. Happy listening in 2014. Hopefully my greetings are all matched to within one decibel!
Hey Guys,
I wonder how much a part the output transformer plays in all this? I ask because the SE amp has a gapped transformer and the PP does not.
I would tend to side with Shoog on this one because push pull cancels even order while SE doesn't. (But I'm an amateur)
Also, how does this argument stack up for SE amps using pentode outputs? the big triodes seem prohibitively expensive for their power output?
I wonder how much a part the output transformer plays in all this? I ask because the SE amp has a gapped transformer and the PP does not.
I would tend to side with Shoog on this one because push pull cancels even order while SE doesn't. (But I'm an amateur)
Also, how does this argument stack up for SE amps using pentode outputs? the big triodes seem prohibitively expensive for their power output?
Just to comment on your point, I just finished my first amp that I was able to do FFTs on the output, which was a push-pull KT88 amp with local feedback on the output tubes and no global loop. I built in a trimpot on the anode loads of the input LTP, so that I could adjust in/out the even harmonics. Even with that adjustment, I couldn't get the 2nd harmonic to be lower than the 3rd. I was surprised as I always thought that p-p amps would be odd harmonic dominated. Attached are distortion spectra taken at 1W and at 10W. My test setup is noisy, but it gets the point across.
Attachments
What I take from your measurements is you have built a PP amp that doesn't properly sum the even order distortions in the output stage. No correction on the input to that circuit will change that.
In a perfect world the second should disappear on the FFT and I hope we all agree the math shows that. I guess you need to really think about where your measurements deviated from the ideal before you make claims that might be challenged.
dave
I agree with this but to extrapolate that to your next statement...
I call BS.
If anyone wants to use science to justify a system, then you need to adhere to the laws of that system. If anything you do deviates from those laws and throws up a red flag, it is your responsibility to take note and correct.
dave
I think, some days I awake and need SE, another day PP, I have four tonearms in the same turntable, some days I say, I like MM, another day or week, MC. Some days I awake and want to be wild and romantic, other days I want to be logic and accurate. Further the discussion is a subjective experience.
In this discussion I read the same said with different words but nothing new under the sun. Anyway without downplaying the exhibitions and shows elecuentes of true sages of electronics with vacuum valves.
In this discussion I read the same said with different words but nothing new under the sun. Anyway without downplaying the exhibitions and shows elecuentes of true sages of electronics with vacuum valves.
It seems to play a significant part. I think you are listening to the things that the SE transformer takes away - ie less bass control and less high frequency extension. The reason I say this is that when people have experimented (Tubelbabs for one) with DC compensated gapless SE, they describe losing the SE magic even though the performance is nominally better.
Shoog
Shoog,
What is DC compensated? Where can I read about it, did tubelab publish anything on it? I was wondering about the possibility of not running DC through the transformer at all. Has anyone ever run the B+ directly to the output tube plates and then AC couled the plate to the output transformer? I've wondered about this as transformers really only work for AC. Or does the standing DC in the transformer have an effect on the sound. That is what you seem to imply on the above post?
What is DC compensated? Where can I read about it, did tubelab publish anything on it? I was wondering about the possibility of not running DC through the transformer at all. Has anyone ever run the B+ directly to the output tube plates and then AC couled the plate to the output transformer? I've wondered about this as transformers really only work for AC. Or does the standing DC in the transformer have an effect on the sound. That is what you seem to imply on the above post?
DC compensated SE is where an equal but opposite DC standing current is applied to a seperate winding to make there be no standing DC in the core. Tubelab made the comment in a thread where various schemes were explored and I don't think he published anything.
Parafeed is another approach, its the approach I have explored (with CCS load) and may explain why I missed the magic of SE.
Shoog
Parafeed is another approach, its the approach I have explored (with CCS load) and may explain why I missed the magic of SE.
Shoog
Dave,
Huh? I fail to see where I made any claim that could be challenged. I just claimed I built a p-p amp that has distortion that is 2nd dominated. Obviously I agree that in an ideal p-p amp there would be no 2nd in the output.
In the case of my amp, the imbalance occurs in the driver stage, and I knew it was going to be a problem in the design phase, which is why I attempted to put an adjustment in the input to help knock it down some. The only surprise to me was that after knocking it down a few dB, the second is still quite a bit higher than the third. It's not a problem, the amp sounds quite nice and I'm happy with it. It wasn't a critical requirement that my amp have less 2nd than 3rd. I was testing out unique circuits with the goal of learning.
My only observation is that real world amps differ from theory. This shouldn't be a surprise or controversial to anyone, since we use ideal components in theory and we can only approximate those in real life.
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