SET amp owners thread

[bonzo75]

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

 

[bonzo75]

Different version of pictures

 

[SVS]

The piano and violins sound good, but the bass sometimes seems loose and bloated.
I think the amp doesn't have enough bass control.
In general, such tests are not adequate enough: you equate your ears to the recording plus the listener's audio system and his ears.

 

[adamaley]

I don't feel that phone recordings/playback convey anything worthwhile besides the enjoyment of hearing wonderful music while looking at images in video. They might convey some relevant datapoints of a system before and after changes are made, but even in that case, there are too many variables, IMO, to not take with a grain of salt.

However, I understand that others find great value in them, so I just move along through those discussions.

Hopefully we do not derail this amazing thread with debates over the role of video in assessing systems.

 

[SVS]

I don't feel that phone recordings/playback convey anything worthwhile besides the enjoyment of hearing wonderful music while looking at images in video. They might convey some relevant datapoints of a system before and after changes are made, but even in that case, there are too many variables, IMO, to not take with a grain of salt.

However, I understand that others find great value in them, so I just move along through those discussions.

Hopefully we do not derail this amazing thread with debates over the role of video in assessing systems.

What I am saying is that the assessment may not be entirely accurate. The general image is well received, but the details, which are much debated here, raise questions.

 

[bonzo75]

What I am saying is that the assessment may not be entirely accurate. The general image is well received, but the details, which are much debated here, raise questions.

All videos are meant to do is provide an interest worth auditioning - or not. I do not see any debated details with friends who follow my classical tastes, records, and videos.

 

[SVS]

All videos are meant to do is provide an interest worth auditioning - or not. I do not see any debated details with friends who follow my classical tastes, records, and videos.

We are all different. I respect your opinion, but mine is a bit different. This is normal.

 

[bonzo75]

We are all different. I respect your opinion, but mine is a bit different. This is normal.

i don’t doubt. There is a way of assessing videos which is further different from subjective tastes and experiences

 

[SVS]

i don’t doubt. There is a way of assessing videos which is further different from subjective tastes and experiences

There will never be objectivity in this matter. I have witnessed many times how one audition was evaluated by different people with a diametrical difference.

 

[Atmasphere]

There will never be objectivity in this matter. I have witnessed many times how one audition was evaluated by different people with a diametrical difference.

To be clear, objectivity left the building when the topic was SETs

The reason people like them is due to how they make distortion, although this is true of any amplifier that has a following. Its just that SETs make so much distortion that if you want anything like 'neutral' you only have about 20% usable power (as opposed to full power right at clipping). If your speakers lack the efficiency needed to work with that sort of power you won't really get to hear what the SET can do.

The thing is, if you put an SET on an even playing field with a push-pull amp, you'll find it has no advantages over that push-pull amp. An 'even playing field' means a PP amp of the same power, made with similar parts quality and similar attention to competent circuit design. Or perhaps the same kind of output tubes as used in the SET (as a non-objective anecdotal example, I have compared a type 45 SET to a type 45 PP amp and the SET was unable to compete in any meaningful way- the PP amp was smoother mids and highs, more detailed, better able to delineate vocals, had better bass, more speed and was overall more engaging) and otherwise the same quality parts.

I really don't think objectivity is anything to worry about here. If we're going to speak truth to power, its only all about fun and nothing else. So just enjoy it. Or get a better amp and enjoy that...

 

[adamaley]

To be clear, objectivity left the building when the topic was SETs

The reason people like them is due to how they make distortion, although this is true of any amplifier that has a following. Its just that SETs make so much distortion that if you want anything like 'neutral' you only have about 20% usable power (as opposed to full power right at clipping). If your speakers lack the efficiency needed to work with that sort of power you won't really get to hear what the SET can do.

The thing is, if you put an SET on an even playing field with a push-pull amp, you'll find it has no advantages over that push-pull amp. An 'even playing field' means a PP amp of the same power, made with similar parts quality and similar attention to competent circuit design. Or perhaps the same kind of output tubes as used in the SET (as a non-objective anecdotal example, I have compared a type 45 SET to a type 45 PP amp and the SET was unable to compete in any meaningful way- the PP amp was smoother mids and highs, more detailed, better able to delineate vocals, had better bass, more speed and was overall more engaging) and otherwise the same quality parts.

I really don't think objectivity is anything to worry about here. If we're going to speak truth to power, its only all about fun and nothing else. So just enjoy it. Or get a better amp and enjoy that...

Dead horse. Beaten.

 

[SVS]

The thing is, if you put an SET on an even playing field with a push-pull amp, you'll find it has no advantages over that push-pull amp. An 'even playing field' means a PP amp of the same power, made with similar parts quality and similar attention to competent circuit design. Or perhaps the same kind of output tubes as used in the SET (as a non-objective anecdotal example, I have compared a type 45 SET to a type 45 PP amp and the SET was unable to compete in any meaningful way- the PP amp was smoother mids and highs, more detailed, better able to delineate vocals, had better bass, more speed and was overall more engaging) and otherwise the same quality parts.

I really don't think objectivity is anything to worry about here. If we're going to speak truth to power, its only all about fun and nothing else. So just enjoy it. Or get a better amp and enjoy that...

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

PP amplifiers have the problem of the first Watt and larger odd harmonics, these are their main disadvantages that make their listening not very comfortable. But there are connoisseurs of such a sound.

You're right about entertainment, but it's interesting to hear other opinions.

 

[acousticsguru]

All videos are meant to do is provide an interest worth auditioning - or not. I do not see any debated details with friends who follow my classical tastes, records, and videos.

I agree with the general idea that such a video, similarly to a review or the opinion of a fellow audiophile whose tastes are to be trusted, may serve as a starting point or springboard so to speak to pursue music or a design or even brand, i.e. to gather first-hand impressions and experience oneself, and form one's own opinion - but they're hardly more than that, at best an amuse-bouche.

Greetings from Switzerland, David.

 

[Atmasphere]

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

PP amplifiers have the problem of the first Watt and larger odd harmonics, these are their main disadvantages that make their listening not very comfortable. But there are connoisseurs of such a sound.

You're right about entertainment, but it's interesting to hear other opinions.

I've heard many SETs. What you are saying (without knowing me, but if we give your comment the benefit of the doubt) suggests that most SETs are junk

You are incorrect about the 1st Watt thing and the larger odd harmonics. The issue is topology; some PP amps may well have the problem you describe, but most don't. They have a different problem, where single-ended and PP circuits are combined in the same amp, which results in both a quadratic non-linearity and a cubic non-linearity, resulting in a prominent 5th harmonic (which is similar but not the same as you describe). That can be avoided with careful design. BTW I'm not saying the 1st Watt isn't important- everyone knows it is. What I am saying is a PP amp can have a 1st Watt better than any SET.

The other apples and oranges (not on an even playing field) have to do with improperly applied negative feedback, which results in a greater amount of higher ordered harmonics (similar to what you might be describing, as that doesn't sound very good) and the class of operation (AB instead of A1).

So often when an SET is compared to a PP amp, the PP amp usually has these three problems thus described.

So to even the playing field, the PP amp needs to have the same class of operation and no feedback, as well as either the same output power at clipping or the same power tubes as the SET (take your pick). I've found though that if you apply feedback properly it does not hurt the 1st Watt at all.

Now what an SET can do that most PP amps with feedback cannot is have a ruler flat distortion vs frequency curve across the audio band. I can get into the engineering about how this is so (and probably did earlier on this thread). Its one of the more salient reasons amps can sound amusical. But you can have a PP amp do that just as well if you know what you're doing.

 

[SVS]

I've heard many SETs. What you are saying (without knowing me, but if we give your comment the benefit of the doubt) suggests that most SETs are junk

You are incorrect about the 1st Watt thing and the larger odd harmonics. The issue is topology; some PP amps may well have the problem you describe, but most don't. They have a different problem, where single-ended and PP circuits are combined in the same amp, which results in both a quadratic non-linearity and a cubic non-linearity, resulting in a prominent 5th harmonic (which is similar but not the same as you describe). That can be avoided with careful design. BTW I'm not saying the 1st Watt isn't important- everyone knows it is. What I am saying is a PP amp can have a 1st Watt better than any SET.

The other apples and oranges (not on an even playing field) have to do with improperly applied negative feedback, which results in a greater amount of higher ordered harmonics (similar to what you might be describing, as that doesn't sound very good) and the class of operation (AB instead of A1).

So often when an SET is compared to a PP amp, the PP amp usually has these three problems thus described.

So to even the playing field, the PP amp needs to have the same class of operation and no feedback, as well as either the same output power at clipping or the same power tubes as the SET (take your pick). I've found though that if you apply feedback properly it does not hurt the 1st Watt at all.

Now what an SET can do that most PP amps with feedback cannot is have a ruler flat distortion vs frequency curve across the audio band. I can get into the engineering about how this is so (and probably did earlier on this thread). Its one of the more salient reasons amps can sound amusical. But you can have a PP amp do that just as well if you know what you're doing.

I don't know you, but your words describe you. In order not to start an absentee discussion on the topic of SET vs PP, read the review about the sound of a good SET

What are some great 300B SET amps $5-7K?

Can't wait to try them at my place How long do you have to wait? I am interested in the result.

www.whatsbestforum.com

Of course, there are PP sound connoisseurs, from my experience it is 1/3, if not 1/4, of the total number of listeners, but I would not say that any PP amp is better than any SET.

I believe that general feedback is death for the sound, so I hardly use it, the most I can afford is unshunted cathode resistors. Therefore, I know very well that the PP amplifier cannot sound good on the bass at low output power. Physics is a hard science and no one has yet been able to overcome its laws. According to these laws, the core material of the output transformer in weak magnetic fields has a low mu. This leads to a drop in the inductance of the output transformer and, as a result, insufficient bass. As the output power increases, the magnetic induction increases, the inductance and bass increase accordingly.
In budget models, this effect is overcome by introducing feedback. This also reduces the magnitude of harmonics, but their spectrum becomes very broad, and the character does not change.
This wide range of harmonics makes the sound dead, almost like transistors.

 

[Atmasphere]

I don't know you, but your words describe you. In order not to start an absentee discussion on the topic of SET vs PP, read the review about the sound of a good SET

What are some great 300B SET amps $5-7K?

Can't wait to try them at my place How long do you have to wait? I am interested in the result.

www.whatsbestforum.com

Of course, there are PP sound connoisseurs, from my experience it is 1/3, if not 1/4, of the total number of listeners, but I would not say that any PP amp is better than any SET.

I believe that general feedback is death for the sound, so I hardly use it, the most I can afford is unshunted cathode resistors. Therefore, I know very well that the PP amplifier cannot sound good on the bass at low output power. Physics is a hard science and no one has yet been able to overcome its laws. According to these laws, the core material of the output transformer in weak magnetic fields has a low mu. This leads to a drop in the inductance of the output transformer and, as a result, insufficient bass. As the output power increases, the magnetic induction increases, the inductance and bass increase accordingly.
In budget models, this effect is overcome by introducing feedback. This also reduces the magnitude of harmonics, but their spectrum becomes very broad, and the character does not change.
This wide range of harmonics makes the sound dead, almost like transistors.

Emphasis added. Neither would I, nor is that what I said.

It is much easier to get bandwidth out of PP output transformers, both in the bass and the highs. So you don't have to compromise in that regard, especially if the PP amp is of the same power as an SET. However you have assumed that all PP amps have output transformers, and some do not. OTLs can be class A, triode and zero feedback as well. With full power bandwidth to 1Hz. So they can make bass that most SETs will not even acknowledge exists.

The problem with feedback is its usually applied to a non-linear feedback node, like the cathode of a tube. If you don't do that, the feedback won't be distorted by the tube prior to executing its mission. Its a simple matter, but for some weird reason most designers simply incorrectly accept there's only one way to do it.

If you solve these problems you can make a very musical PP amp that is every bit as involving as the best SET. Its not rocket science but it does require pragmatism.

 

[SVS]

Emphasis added. Neither would I, nor is that what I said.

It is much easier to get bandwidth out of PP output transformers, both in the bass and the highs. So you don't have to compromise in that regard, especially if the PP amp is of the same power as an SET. However you have assumed that all PP amps have output transformers, and some do not. OTLs can be class A, triode and zero feedback as well. With full power bandwidth to 1Hz. So they can make bass that most SETs will not even acknowledge exists.

The problem with feedback is its usually applied to a non-linear feedback node, like the cathode of a tube. If you don't do that, the feedback won't be distorted by the tube prior to executing its mission. Its a simple matter, but for some weird reason most designers simply incorrectly accept there's only one way to do it.

If you solve these problems you can make a very musical PP amp that is every bit as involving as the best SET. Its not rocket science but it does require pragmatism.

I did not write that with the same tubes and components, I repent.

Yes, you are right, there are other OTL.

OTL is a combination of tubes, active elements that work with weak currents and a speaker that requires a large current. The combination, in my opinion, is unnatural. Tubes are used in modes where their service life is short. In addition, they are used inefficiently: in the SET amplifier, I can get an output power of 20 W from the 6?33?, for the OTL amplifier, at least 4 such tubes are needed for this.

In OTL amps there is a problem of preventing direct current through the speaker. And this is only feedback or an output electrolytic capacitor. In both cases, the sound becomes worse.

 

[morricab]

To be clear, objectivity left the building when the topic was SETs

The reason people like them is due to how they make distortion, although this is true of any amplifier that has a following. Its just that SETs make so much distortion that if you want anything like 'neutral' you only have about 20% usable power (as opposed to full power right at clipping). If your speakers lack the efficiency needed to work with that sort of power you won't really get to hear what the SET can do.

The thing is, if you put an SET on an even playing field with a push-pull amp, you'll find it has no advantages over that push-pull amp. An 'even playing field' means a PP amp of the same power, made with similar parts quality and similar attention to competent circuit design. Or perhaps the same kind of output tubes as used in the SET (as a non-objective anecdotal example, I have compared a type 45 SET to a type 45 PP amp and the SET was unable to compete in any meaningful way- the PP amp was smoother mids and highs, more detailed, better able to delineate vocals, had better bass, more speed and was overall more engaging) and otherwise the same quality parts.

I really don't think objectivity is anything to worry about here. If we're going to speak truth to power, its only all about fun and nothing else. So just enjoy it. Or get a better amp and enjoy that...

Push pull by its very nature provides a large degree of even order distortion cancellation, leaving the odd order harmonics behind and exposed, if the two halves of the push pull are perfectly matched. The even order that creeps into the measurements of most push pull amps is due to the non-perfect execution and/or device matching. Of course this could also be done deliberately. So, the pattern is quite different between the two topologies and this has audible consequences. Keith Howard did experiments on these patterns by adding the distortion digitally to recordings and he found that a predominantly odd order pattern was by far the most offensive sounding. The same level of odd order distortion with the even order added back in was significantly more palatable. So much for your hypothesis that the 3rd order also masks like the 2nd. You need the preceeding harmonic to be higher than the following harmonic to provide the masking. Remove the evens and you remove the masking as the gap is too large to the next harmonics. The odd harmonics above 3rd are also well known to be unpleasant to humans, often metallic and edgy sounding. Expose them and that edge creeps in and sounds unnatural.

It is also wrong to say that only 20% of the power is usable. If a SET is rated at 20 watts with 3% distortion and nearly all of that is 2nd order, then nearly all of that 20 watts is certainly usable without much in the way of AUDIBLE distortion. AND if your speaker is sensitive, say like 95dB or higher, then you are probably never using much more than 1 watt anyway and you have a lot of headroom for peaks, which at those higher SPLs then 3 or probably even 10% THD (if mostly low order) won't be audible (Cheever makes it clear the audibility of distortion scales with SPL, which is why he has an SPL term in his equation).

 

[matsurus]

Push pull by its very nature provides a large degree of even order distortion cancellation, leaving the odd order harmonics behind and exposed, if the two halves of the push pull are perfectly matched. The even order that creeps into the measurements of most push pull amps is due to the non-perfect execution and/or device matching. Of course this could also be done deliberately. So, the pattern is quite different between the two topologies and this has audible consequences. Keith Howard did experiments on these patterns by adding the distortion digitally to recordings and he found that a predominantly odd order pattern was by far the most offensive sounding. The same level of odd order distortion with the even order added back in was significantly more palatable. So much for your hypothesis that the 3rd order also masks like the 2nd. You need the preceeding harmonic to be higher than the following harmonic to provide the masking. Remove the evens and you remove the masking as the gap is too large to the next harmonics. The odd harmonics above 3rd are also well known to be unpleasant to humans, often metallic and edgy sounding. Expose them and that edge creeps in and sounds unnatural.

It is also wrong to say that only 20% of the power is usable. If a SET is rated at 20 watts with 3% distortion and nearly all of that is 2nd order, then nearly all of that 20 watts is certainly usable without much in the way of AUDIBLE distortion. AND if your speaker is sensitive, say like 95dB or higher, then you are probably never using much more than 1 watt anyway and you have a lot of headroom for peaks, which at those higher SPLs then 3 or probably even 10% THD (if mostly low order) won't be audible (Cheever makes it clear the audibility of distortion scales with SPL, which is why he has an SPL term in his equation).

I don't really disagree with most what you re saying, but Nelson Pass has written about this topic of third harmonics, they made several test about this in pass labs how different listeners feel about harmonics:
"

Harmonic Distortion and Sound​

Many audiophiles believe that 2nd harmonic is to be preferred over 3rd harmonic. Certainly it is simpler in character, and it is well agreed that orders higher than third are more audible and less musical. However when given a choice between the sound of an amplifier whose characteristic is dominantly 2nd harmonic versus 3rd harmonic, a good percentage of listeners choose the 3rd.

I have built many examples of simple 2nd and 3rd harmonic “types” of amplifiers over the last 35 years. When I say “types” I mean that they used simple Class A circuits described as “single-ended” versus “push-pull” and so tended to have a 2nd harmonic versus 3rd harmonic in the character of their distortion, but were not made to deliberately distort.

Anecdotally, it appears that preferences break out roughly into a third of customers liking 2nd harmonic types, a third liking 3rd harmonic, and the remainder liking neither or both. Customers have also been known to change their mind over a period of time.

However the issue is partially obscured by the fact that the 3rd harmonic type amplifiers usually have lower total distortion. Third harmonic usually appears with a negative coefficient, resulting in what we think of as “compressive” - the example in figure 3. It's worth noting that odd orders on nonlinearity also can be seen altering the amplitude of the fundamental tone -something a distortion analyzer doesn't ordinarily display.

Audiophiles have been accused of using 2nd or 3rd harmonic distortion as tone controls to deliberately alter the sound. I suppose that there are people who like it that way, but I don't think this is generally the case. For reasons which will become clearer when we talk about inter-modulation distortion, high levels of any harmonic become problematic with musical material having multiple instruments, and the argument that 2nd or 3rd adds “musicality” doesn't quite hold up.

The sound of 2nd order type circuits is often praised as “warm” and by comparison 3rd order type circuits are often noted for “dynamic contrast”. 2nd order type amplifiers seem to do particularly well with simple musical material, and 3rd order types generally seem to be better at more complex music."


-While i don't really have firsthand experience in all aspects of how different distortion spectrum "feel" (and nelson writes), i agree about third harmonic being "dynamic". I actually absolutely detest third harmonic spectrum from firsthand experience, but i know several people that really prefer amplifiers that produce this kind of spectrum VS Hiraga descending distortion from second order that i personally like..

Horses for courses..

 

[acousticsguru]

“The sound of 2nd order type circuits is often praised as “warm” and by comparison 3rd order type circuits are often noted for “dynamic contrast”. 2nd order type amplifiers seem to do particularly well with simple musical material, and 3rd order types generally seem to be better at more complex music."

This aspect, the complexity of the music and/or number of instruments playing, tends to get overlooked - agree wholeheartedly. It’s one reason (of several) why classical music aficionados don’t seem to like the same systems (or components such as amps and DACs) as audiophiles who listen to different types of music - something I’ve been noticing for years. Needless to say, once one starts to pay attention to audiophiles’ tastes in music, it’s easy to understand why systems that do everything equally well are the rarest: because mostly everyone prioritizes.

Greetings from Switzerland, David.