SET amp owners thread

But it's also in the SET subforum of the site. Not sure why this should be where an OTL vs SET debate has to be flared up by an OTL manufacturer. A separate thread in this subforum, or even better, in the general forum might be more appropriate.

even if I´m retired I don´t have time to write essays like they do in this forum

had planned to install the Tommy Hørning nanocrystalline AVC today, but postponed since we´re testing NNNN TRENT 25 here on monday, and SODs law says something will go wrong...

Rob181 said:

Now why would he do that - its his IP & you are an amp builder. Buy one that go till your hearts content...

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I make amplifiers that I like. And I don't regularly tell anyone that they are better than others. But I think it's true.

SET lovers are usually the hardest to convince to switch. This'll be the hardest battle ever

SVS said:

There is no electrical DC feedback in your circuit diagram, but there is an option to do the feedback function manually. And this function is performed by the user. Huge milliammeters on the front of the devices prove the importance of these manipulations.
Maybe in the latest models you are using an analog zero adjustment on the output. But this is impossible without feedback. Will you show a schematic diagram that proves otherwise?

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Other than your question, the rest of this post is nonsense.

SVS said:

You firmly believe that things that are bad for you should be better for others. It is very self-assured, but has no foundation.

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This is too. Without knowing me, you have no idea if there is a foundation or not. Its a shot in the dark.

morricab said:

Trolling? Sorry, but who is coming on a SET owners thread and telling them that their SETs are no good and that your amps make lower distortion (Duh!) and better distortion (highly questionable for all the reasons I have laid out before. Also, contra to most of the literature that is available around psychoacoustics of distortion)? You don't think this will result in pushback from experienced listeners who have come to prefer the sound of SET amplification? Many of us have used OTL in the past. I myself have owned two different kinds one of which used 6C33C and the other used some TV tube type that eludes me now (EL509 or something?). I have not owned your amps but heard them a number of times at other people's homes and at shows. Not convinced enough to buy.

I haven't heard your new Ga based Class D but feedback, while positive, doesn't confirm that they sound like tube amps...and what does sounding like a tube amp even mean? You are posting on a SET thread, so when you say tube amp, why would you mean a push/pull tube amp or an OTL? You do realize that SET amps generally sound very different from most push/pull type designs, right? I have head some that are close and those are Class A triode (like 300B or 2A3)...but still not the same sound.

Likewise, telling them that only 20% of the power is "usable" because of distortion, ignoring the fact that A) most SET users have high sensitivity speakers where only a few watts are needed to get high SPL and B) That the audibility of distortion is dependent on absolute SPL, which works perfectly then with amps that increase THD with increasing power because the masking holds up as the SPL increases...assuming the CHARACTER of that distortion doesn't change with SPL...in most cases it doesn't...there are always exceptions. As an example. Let's say you have 100dB speakers and an 8 watt (3%THD) 300B amp. At 8 watts the SPL level will be about 109 dB for a single speaker so a pair at 3meters will still be easily 105+ dB SPL or more. Do you think 3% THD, that is mostly 2nd and 3rd harmonic, will be at all audible with 105dB SPL? Most of the time that amp will be cruising at mW because most people listen at well below 100dB. Average levels of 85dB are already quite loud and i rarely listen that loud. Even if that amp makes 4W at 1% THD that is over 100dB SPL at the listening position. That is 50% the rated power. Do you think that 1% is audible with 100dB levels...especially if those are mS long peaks and not sustained levels? Get real and think about what you post!

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My comments only contradict you; the texts and tomes you've trotted out don't defend your position as we've already seen.

The goal of any decent stereo system should be to sound like real music. Now if that isn't your goal then I am barking up the wrong tree! If SETs are bringing home the bacon, there should be no fear from the PP community (if there is such a thing); if SETs are so much better than the SET community should welcome comments from those that have a different outlook. That I get this sort of nonsensical pushback belies that.

You write as if I've no experience with SETs. That SVS guy does too. He writes as if I didn't design the OTLs we make and as a result shoots himself in the foot. It might interest you to know that I've been studying and designing SETs for 35 years. I've looked at hundreds of schematics and tried a lot of the ideas they show; I know SET designers on a first name basis and reviewed patent applications for some of them and advised others. The SETs are fun, but they aren't as musical as they could be, and they aren't as musical as the amps we make. I've heard some that come close, but they made 1/4 of the power of our M-60 and cost 4x as much. So its easy to make an argument for buyer awareness.

Robert Harley wrote a puff piece in Stereophile a few years ago about various kinds of amps- their strengths and weaknesses. In that article he commented that 'no one knows why SETs measure so poorly yet sound so good' (paraphrasing). He apparently didn't bother to actually ask anyone that knew about stuff like that. The fact is we do know why this happens and better yet, these days measurement equipment has gotten good enough that we can measure what it is that causes an amp to sound good. You and I went around on that bit a year or two ago.

SETs make a lot of higher ordered harmonics- more than any other kind of amp. But they make a lot of lower ordered harmonics too; they work because of the ear's masking principle. How about an amp that makes only lower ordered harmonics?? Would that be better?

My comments about '20-25% of full power' are quite accurate. It is because people ignore this aspect of SET that you hear how they are so 'dynamic' for how little power they have; a very common comment in user posts and reviews. You can safely substitute the word 'distortion' for the word 'dynamics' in 90% of these comments and conversations without changing their meaning. IOW the 'dynamics' is caused by distortion. If you really want to hear what an SET is all about, you need a speaker that is efficient enough that you never pass that 20% point.

adamaley said:

But it's also in the SET subforum of the site. Not sure why this should be where an OTL vs SET debate has to be flared up by an OTL manufacturer. A separate thread in this subforum, or even better, in the general forum might be more appropriate.

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It was this comment

You haven't heard a good SET amplifier. Any PP amplifier is nervously smoked in a corner compared to it.

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directed at me without any knowledge about me whatsoever that started the latest set of missives.

I'm here because I take an interest in tube amps in general and I find SETs more interesting then big PP pentode based amps. SETs have things in common with other tube amps; class of operation, component quality, DHTs and so on. So I follow this thread.

Why are you Trolling this SET thread in the SET Amplification sub form … Sales of expensive to run room heaters and placky amps a little slow this month perhaps ?

Atmasphere said:

It was this comment

directed at me without any knowledge about me whatsoever that started the latest set of missives.

I'm here because I take an interest in tube amps in general and I find SETs more interesting then big PP pentode based amps. SETs have things in common with other tube amps; class of operation, component quality, DHTs and so on. So I follow this thread.

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You started it here with this post:


You were trolling and got a riposte and took offense?

I would also like to read something else than this one thing on repeat ad infinitum..
it really starts to feel like trolling at this point..

Atmasphere said:

SETs make a lot of higher ordered harmonics- more than any other kind of amp. But they make a lot of lower ordered harmonics too; they work because of the ear's masking principle. How about an amp that makes only lower ordered harmonics?? Would that be better?

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Justify this statement. You are the master of links, and here are only your words.

Argonaut said:

Why are you Trolling this SET thread in the SET Amplification sub form … Sales of expensive to run room heaters and placky amps a little slow this month perhaps ?

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Not trolling. AFAIK I've been factual. that room heater thing is kinda funny- is that the pot and kettle thing? Actually I explained my presence here in my last post.

SVS said:

Justify this statement. You are the master of links, and here are only your words.

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You're a designer right? And you didn't know this??

adamaley said:

You started it here with this post:

SET amp owners thread

Some short clips on piano 2nd The phone loses the breath in the midbass on this one, use headphones or sound Bar one of them is a mono

www.whatsbestforum.com

You were trolling and got a riposte and took offense?

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I didn't take offense. This being the internet, I don't know most of the people with which I interact on it. So its very hard to take things personally and I don't.

That comment at the link was a simple one and I'm surprised anyone took that at anything other than face value. Most of the SET people I know don't worry themselves too much about measurements, which are usually the thing trotted out by people who consider themselves 'objectivists' (although IMO they are anything but, often doing the very thing that they fault the 'subjectivists' for)...

I was merely pointing out that the idea that someone was being objective when playing an SET, listening for its attributes really isn't a thing.

Atmasphere said:

SETs make a lot of higher ordered harmonics- more than any other kind of amp. But they make a lot of lower ordered harmonics too; they work because of the ear's masking principle. How about an amp that makes only lower ordered harmonics?? Would that be better?

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That seems better to me.

Atmasphere said:

Other than your question, the rest of this post is nonsense.

This is too. Without knowing me, you have no idea if there is a foundation or not. Its a shot in the dark.



My comments only contradict you; the texts and tomes you've trotted out don't defend your position as we've already seen.

The goal of any decent stereo system should be to sound like real music. Now if that isn't your goal then I am barking up the wrong tree! If SETs are bringing home the bacon, there should be no fear from the PP community (if there is such a thing); if SETs are so much better than the SET community should welcome comments from those that have a different outlook. That I get this sort of nonsensical pushback belies that.

You write as if I've no experience with SETs. That SVS guy does too. He writes as if I didn't design the OTLs we make and as a result shoots himself in the foot. It might interest you to know that I've been studying and designing SETs for 35 years. I've looked at hundreds of schematics and tried a lot of the ideas they show; I know SET designers on a first name basis and reviewed patent applications for some of them and advised others. The SETs are fun, but they aren't as musical as they could be, and they aren't as musical as the amps we make. I've heard some that come close, but they made 1/4 of the power of our M-60 and cost 4x as much. So its easy to make an argument for buyer awareness.

Robert Harley wrote a puff piece in Stereophile a few years ago about various kinds of amps- their strengths and weaknesses. In that article he commented that 'no one knows why SETs measure so poorly yet sound so good' (paraphrasing). He apparently didn't bother to actually ask anyone that knew about stuff like that. The fact is we do know why this happens and better yet, these days measurement equipment has gotten good enough that we can measure what it is that causes an amp to sound good. You and I went around on that bit a year or two ago.

SETs make a lot of higher ordered harmonics- more than any other kind of amp. But they make a lot of lower ordered harmonics too; they work because of the ear's masking principle. How about an amp that makes only lower ordered harmonics?? Would that be better?

My comments about '20-25% of full power' are quite accurate. It is because people ignore this aspect of SET that you hear how they are so 'dynamic' for how little power they have; a very common comment in user posts and reviews. You can safely substitute the word 'distortion' for the word 'dynamics' in 90% of these comments and conversations without changing their meaning. IOW the 'dynamics' is caused by distortion. If you really want to hear what an SET is all about, you need a speaker that is efficient enough that you never pass that 20% point.

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The amp you describe that makes only low order harmonics is a SET at low power. No other amp design does this. None of your designs do this. As your amps cancel even orders there is no 2nd, or greatly reduced 2nd and 4th. Everything 5th and above is unpleasant and your amps all
make higher orders, primarily of the unpleasant odd kind.

Looks like it hit 1% THD at 20 watts… the Amplifon SET42se gets 32 watts with 1% THD.

Atmasphere said:

You're a designer right? And you didn't know this??

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I know the opposite, and I ask where did you read such nonsense?
I already wrote about my experience above, and later it was confirmed by another study: PP amps, and OTL is a PP amp, 1/3 of listeners like it. I think that you are trying to convert someone from the rest of the listeners to your faith.

Please look on page 35 for differential amp behavior. Triodes without feedback only make odd orders and at pretty high levels.

morricab said:

The amp you describe that makes only low order harmonics is a SET at low power. No other amp design does this. None of your designs do this. As your amps cancel even orders there is no 2nd, or greatly reduced 2nd and 4th. Everything 5th and above is unpleasant and your amps all
make higher orders, primarily of the unpleasant odd kind.

SoundStage! Measurements - Atma-Sphere MA-1 Mk II.2 Mono Amplifiers: Measurements (2/2002)

Looks like it hit 1% THD at 20 watts… the Amplifon SET42se gets 32 watts with 1% THD.

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As best we can figure, when Bascomb did that measurement 23 years ago, he grounded one of the speaker terminals. This is very easy to do with most test equipment! That unbalances the drive to the power tubes so distortion takes off pretty fast. Typically the MA-1 can make about 1% at full power and if you are careful with the tubes you can get it down to 0.5%.

To properly measure the distortion you need a differential probe at the least so you can look at the balanced output.

morricab said:

https://www.its.caltech.edu/~musiclab/feedback-paper-acrobat.pdf

Please look on page 35 for differential amp behavior. Triodes without feedback only make odd orders and at pretty high levels.

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I've read that paper before. It has errors. One of them is they didn't explore the impact of the constant current source, so didn't investigate topologies of the CCS as a result.

The means they used for feedback is degeneration resistors, which really messes with the ability of the differential amp to actually be differential.

Having worked with differential amplifiers for 40 years, I can tell you the way you set up the CCS and then set the operating point has an enormous effect on the resulting circuit. The better the CCS, the better the diff amp performs and you can't have that performance if there are degeneration resistors in the circuit.

You might also note that the paper is based on simulation rather than actual tubes and so the tube type, which has an effect as well, isn't specified as there isn't one. This paper was an interesting read until I realized that it really doesn't pertain to real life.