What are the advantages/disadvantages of different amp topologies?

[Rensselaer]

What topologies are the best sounding amps you have heard?

I already said what sounds best to me. What topologies are the best sounding amps that you have heard?

 

[morricab]

I already said what sounds best to me. What topologies are the best sounding amps that you have heard?

Here is a relative ranking based on what I have heard over the years:
1) Top Notch SETS and Single ended hybrids (like Aries Cerat Triode FET, which is actually a single amplification element).
3) Class A PP triode with no feedback. The relatively new Thrax all 300B amp could be really good sounding.
4) OTL
6) Class A no feedback hybrids (PP type)

Still haven't heard SET OTL but they exist and could be quite interesting.

Anything ranked lower than this there is no way I could live with it. Mainly 1-3 are the only ones seriously considered anymore. I have had 3 different OTLs and while there is a definite wow factor to them, I found that they had flaws in terms of completeness to the sound (hard to explain but I know it when I hear it) that ultimately made me give them up.

 

[Rensselaer]

Here is a relative ranking based on what I have heard over the years:
1) Top Notch SETS and Single ended hybrids (like Aries Cerat Triode FET, which is actually a single amplification element).
3) Class A PP triode with no feedback. The relatively new Thrax all 300B amp could be really good sounding.
4) OTL
6) Class A no feedback hybrids (PP type)

Still haven't heard SET OTL but they exist and could be quite interesting.

Anything ranked lower than this there is no way I could live with it. Mainly 1-3 are the only ones seriously considered anymore. I have had 3 different OTLs and while there is a definite wow factor to them, I found that they had flaws in terms of completeness to the sound (hard to explain but I know it when I hear it) that ultimately made me give them up.

I owned a First Watt F3 for awhile, it used JFETs for amplification only (not hybrid). To me, it lacked the emotion of a good class A SET amplifier, but could emulate drum wack’s fantastically when driven by the Shindo Massetto pre. What about emotion in regards the Aries Cerat Triode-FET hybrid (Or is it strictly a FET acting like a triode)?

 

[acousticsguru]

Ipsofacto; I'm not saying one can't use solid state to make early mono recordings "un-palatable"?

Needless to say, my point is whatever is going to make one listen is "good", and in this particular case, listening deep into historical recordings via a revealing playback system gleaning a maximum of information might do the trick, as may trying to "upholster" their sometimes craggy sound for a more enjoyable experience, pointless to argue with either approach if it works. It's true some audiophiles use recordings to listen to systems, while the music lover will think of his or hers as a means to an end.

Greetings from Switzerland, David.

 

[acousticsguru]

What is needed from this highly experienced and knowledgeable group after consultation is some sort of agreement as to what everyone agrees makes the greatest real difference in "audible" outcome.

For instance, I said that, IMHO, over-engineering with loads of electronic processes applied between source and speaker, perhaps to correct "measurements" or to cut costs ( such as using a diodes in place of more expensive rectifier tubes), ruins the sound. I also said, IMHO, that designing a simple circuit with the lowest parts number but with the best parts available usually sounds best. Atmosphere, agreed to the simple design with excellent parts idea, but only as a segue to advertise his own OTL amplifiers.

All I've learnt here so far is that the pundits (I'm not one of them) do not agree on this. When it comes to loudspeakers, I remember taking a purist approach decades ago, in the meantime superseded by result-oriented, so not knowing enough about amplifier design to be able to contribute to the discussion in terms of technicalities, I'm still wondering if there are parallels.

Greetings from Switzerland, David.

 

[acousticsguru]

I owned a First Watt F3 for awhile, it used JFETs for amplification only (not hybrid). To me, it lacked the emotion of a good class A SET amplifier, but could emulate drum wack’s fantastically when driven by the Shindo Massetto pre. What about emotion in regards the Aries Cerat Triode-FET hybrid (Or is it strictly a FET acting like a triode)?

Funny you'd bring up drum whacks and Triode-FET - we listened to kick drum whacks (e.g. on Todd Cochran's "Behind the Mask", recorded by David Manley) all day yesterday, among other with Aries Cerat Ianus Essentia mono blocks, whose sound I do find solid state like but in the best sense of the term (no tube amp I've ever heard does, specifically, kick drum whacks quite as realistically as the best solid state - I realize I'm putting myself in a spot saying this here, maybe I'll just refrain from checking replies for a couple of days, LOL!).

Greetings from Switzerland, David.

 

[acousticsguru]

I owned a First Watt F3 for awhile, it used JFETs for amplification only (not hybrid). To me, it lacked the emotion of a good class A SET amplifier, but could emulate drum wack’s fantastically when driven by the Shindo Massetto pre. What about emotion in regards the Aries Cerat Triode-FET hybrid (Or is it strictly a FET acting like a triode)?

While I haven’t yet felt the need to duck because of what I said above, let me add that “emotion” to me is a function of music. There’s no getting emotional over gear, unless it is one’s sole inheritance from a loved one. From my perspective, what systems “contribute” is distraction, which precludes emotion. So when a drum whack makes me almost leap out of my seat as it would in a live concert, and a tube amp slightly softens bass response, that’s nowhere as decisive as the fact that a drum whack isn’t just bass, and what hinders my emotion is inevitably when my attention is drawn to a part rather than the whole. The musical properties that let us engage with the emotional content, to me are about coherence and timing, and of course tone (which is big when one is primarily a classical music aficionado like me), apart, quite simply, from anything that doesn’t belong there (the very definition of distraction). In general, I can’t bring myself to say that tube gear or solid state does all three better than the other, the point is the tradeoff must not be such that one isn’t connecting to one’s favorite music. In a nutshell, even if I know I’ll get in trouble saying I haven’t heard as realistic a kick drum whack from a tube amp as solid state, I say so as someone who owns and loves, among other, tube smps, and since I seem to listen to an even greater proportion of classical than I used to, it may be that tone makes a greater proportion of the music I listen to nowadays speak or connect to me (rather than vice versa - if I, the listener, have to bring emotion to the table, then what would I need great gear for?). But, as I told @christoph on Sunday morning, I occasionally miss the realism of a kick drum whack as played back through a Spectral system, engaging me with a type of music I used to listen to more often but now do more rarely - that’s how our playing kick drum whacks on several systems came about. It’s partly an educated guess based on inference (I know all those systems having heard them many times), but I’ll venture to say the Triode-FET has an edge in this department, possibly because it sounds more solid state than tube to me anyways, having said that, I made sure to play some music based on tone (e.g. massed strings), and there I cannot say the scale was tipping (nor isn’t generally speaking) the same direction for me, so that’s that.

Greetings from Switzerland, David.

 

[acousticsguru]

Let me ask what to me is the relevant question discussing what’s “best”: if one compared X recordings of Bach’s Chaconne (last movement of a work for solo violin, the Partita No. 2 in D minor, BWV 1004) - the kind of thing I like to do on a lazy Sunday - which playback do people around here consider “better”, the one that’ll allow the listener to tell X interpretations (not to mention violins used) apart, or the one that’ll make a greater proportion sound pleasing (even if that sonically implies greater sameness among those X performances, and hence lesser differentiation)? Don’t just reply “both”, as that’s what we all strive for in our pursuit of the musically “perfect” system.

Greetings from Switzerland, David.

 

[Rensselaer]

While I haven’t yet felt the need to duck because of what I said above, let me add that “emotion” to me is a function of music. There’s no getting emotional over gear, unless it is one’s sole inheritance from a loved one. From my perspective, what systems “contribute” is distraction, which precludes emotion. So when a drum whack makes me almost leap out of my seat as it would in a live concert, and a tube amp slightly softens bass response, that’s nowhere as decisive as the fact that a drum whack isn’t just bass, and what hinders my emotion is inevitably when my attention is drawn to a part rather than the whole. The musical properties that let us engage with the emotional content, to me are about coherence and timing, and of course tone (which is big when one is primarily a classical music aficionado like me), apart, quite simply, from anything that doesn’t belong there (the very definition of distraction). In general, I can’t bring myself to say that tube gear or solid state does all three better than the other, the point is is the tradeoff must not be such that one isn’t connecting to one’s favorite music. In a nutshell, even if I know I’ll get in trouble saying I haven’t heard as realistic a kick drum whack from a tube amp as solid state, I say so as someone who owns and loves, among other, tube smps, and since I seem to listen to an even greater proportion of classical than I used to, it may be that tone makes a greater proportion of the music I listen to nowadays speak or connect to me (rather than vice versa - if I, the listener, have to bring emotion to the table, then what would I need great gear for?). But, as I told Christoph on Sunday morning, I occasionally miss the realism of a kick drum whack as played back through a Spectral system, engaging me with a type of music I used to listen to more often but now do more rarely - that’s how our playing kick drum whacks on several systems came about. It’s partly an educated guess based on inference (I know all those systems having heard them many times), but I’ll venture to say the Triode-FET has an edge in this department, possibly because it sounds more solid state than tube to me anyways, having said that, I made sure to play some music based on tone (e.g. massed strings), and there I cannot say the scale was tipping (nor isn’t generally speaking) the same direction for me, so that’s that.

Greetings from Switzerland, David.

I agree, distraction, caused by some hi-fi aspect of the playback, detracts from the emotion one feels when listening to music without distractions. Instead, I prefer tonally perfect, real as life, music waffling over my body like gentle waves on a tropical shore. That is the emotion I speak of; not over the equipment, but over the presentation that some equipment is capable of producing.

I am reminded of my friend Jim’s system that Kedar and I recently heard. He was driving the top end of his large horn speakers with a 300B SET, the bottom with a small class-D amplifier (passive crossovers). The system was heard only through the 300B SET, but lost grip of the bass. The class D amp replaced, the system was much better balanced. Still, not magic, until he swapped out his custom two box pre and separate phono stage for an old Audio Note Japan preamp with phono, then it sounded sublime. There was no distractions, just lovely orchestral music filling the room. As real to life as I have ever heard from artificial means.

Was the magic due to the horn speakers? The Kondo silver-wire pre-amp? The use of a class D amp to deal with bass while a 300B SET managed mids and top end? He said his cables were nothing special so can’t be that. There were no room tuning devices in the room so not that either. All I can say is that after swapping in and out different components and topologies, IMHO, Jim’s system reached that goal. I just can’t explain how exactly it did.

 

[acousticsguru]

I agree, distraction caused by some hi-fi aspect of the playback, detracts from the emotion one feels when listening to music without distractions. Instead, I prefer tonally perfect, real as life, waffing over your body like gentle waves on a tropical shore. That is the emotion I speak of (not over the equipment, but over the presentation that some equipment is capable of producing.

I am reminded of my friend Jim’s system that Bonzo and I recently heard. He was driving the top end of his large horn speakers with a 300B SET, the bottom with a small class-D amplifier (passive crossovers). The system was ok until he installed an Audio Note Japan preamp with phono, then it sounded sublime. There was no distractions, just lovely orchestral music filling the room. As real to life as I have ever heard from artificial means.

Did he add the preamp or replace another with it?

Greetings from Switzerland, David.

 

[Rensselaer]

Did he add the preamp or replace another with it?

Greetings from Switzerland, David.

Replaced with another

 

[acousticsguru]

Replaced with another

Not surprising then. Occasionally, adding a preamp may have this effect, although rarely without (even if only minor) drawbacks. I actually remember listening to a system where someone used two preamps in series.

Greetings from Switzerland, David.

 

[Rensselaer]

Not surprising then. Occasionally, adding a preamp may have this effect, although rarely without (even if only minor) drawbacks. I actually remember listening to a system where someone used two preamps in series.

Greetings from Switzerland, David.

It is my opinion that though the change of phono/pre-amp at the end of the process pulled everything together, I would not apportion all the improvement to it. Rather, I would attribute the final product to the synergy of each component in combination.

I mentioned the make of the pre-amplifier (which possibly influenced your comment above). I see now that I should not have done that. This thread is to uncover design topology that leads to audio bliss, not to sell specific products.

What I hoped the example of Jim’s system would cause those interested to ponder was; sublime sound was achieved without room tuning, without dedicated power supplies ( however he does have solar panels and battery setup), without expensive interconnects or power cables, bi-amped using a Class D amplifier (through passive crossovers) to handle the bass while a 300B SET handle the mids and top end, and that into large high-efficiency horn speakers.

Take from this what you will. As for me? I regret spending so much on high end power cords. I have not added commercial sound absorbers/deflectors to my listening room so far and am unlikely to in the future. I already use SET’s and horn speakers, but am buying another SET amp for my system (211’s) and will see how the system sounds with it alone, however, if not great I will contact the maker of my passive crossovers to see if he could possibly split it into a crossover with two inputs, one for up to 500 Hz, the other for above 500 Hz so that I can bi-amp (Considering a Class D for the bottom end).

 

[acousticsguru]

It is my opinion that though the change of phono/pre-amp at the end of the process pulled everything together, I would not apportion all the improvement to it. Rather, I would attribute the final product to the synergy of each component in combination.

I mentioned the make of the pre-amplifier (which possibly influenced your comment above). I see now that I should not have done that. This thread is to uncover design topology that leads to audio bliss, not to sell specific products.

What I hoped the example of Jim’s system would cause those interested to ponder was; sublime sound was achieved without room tuning, without dedicated power supplies ( however he does have solar panels and battery setup), without expensive interconnects or power cables, bi-amped using a Class D amplifier (through passive crossovers) to handle the bass while a 300B SET handle the mids and top end, and that into large high-efficiency horn speakers.

Take from this what you will. As for me? I regret spending so much on high end power cords. I have not added commercial sound absorbers/deflectors to my listening room so far and am unlikely to in the future. I am buying another SET amp for my system (211’s) and will see how the system sounds with it alone, however, if not great I will contact the maker of my passive crossovers to see if he could possibly split it into a crossover with two inputs, one for up to 500 Hz, the other for above 500 Hz so that I can bi-amp.

Actually it's not the make of the preamp that made me say so (you didn't mention what it replaced either), but the fact that for years I used to drive power amps directly with DACs, or so-called integrated amps that in reality are power amps with input attenuators, and noticing tradeoffs either way (with and without preamp), but in general agree with my audiophile buddies that using a preamp (or real integrated amp that does feature a preamp stage) gives an overall more musical result (again, on average, in the majority of systems I've heard, still something one needs to try out). Even so, I'm still on the fence which I prefer in one of my systems, most likely because the DAC there now has an improved output stage.

While "everything matters", I agree power cords feature pretty much dead last on my priorities list as well (besides not using stock, those tend to brighten sound). Room treatment fairly high up (had an acoustic ceiling installed as part of a renovation, what a difference that made, plus it's not intrusive as some treatments that occupy space and look awful).

Greetings from Switzerland, David.

 

[Rensselaer]

Actually it's not the make of the preamp that made me say so (you didn't mention what it replaced either), but the fact that for years I used to drive power amps directly with DACs, or so-called integrated amps that in reality are power amps with input attenuators, and noticing tradeoffs either way (with and without preamp), but in general agree with my audiophile buddies that using a preamp (or real integrated amp that does feature a preamp stage) gives an overall more musical result (again, on average, in the majority of systems I've heard, still something one needs to try out). Even so, I'm still on the fence which I prefer in one of my systems, most likely because the DAC there now has an improved output stage.

While "everything matters", I agree power cords feature pretty much dead last on my priorities list as well (besides not using stock, those tend to brighten sound). Room treatment fairly high up (had an acoustic ceiling installed as part of a renovation, what a difference that made, plus it's not intrusive as some treatments that occupy space and look awful).

Greetings from Switzerland, David.

The 211 based SET's I ordered from Sound Gate/Otomon in Japan are sent with volume pots for use sans pre-amplifier. I see that in general you preferred the sound of your system when using a pre-amplifier despite the volume pots ... that is, until you bought a DAC with an improved output stage (but still on the fence). I intend to run mine directly from my Ypsilon VPS100 phono stage. Have you any experience going pre-less with phono stages?

 

[Aries Cerat]

While I haven’t yet felt the need to duck because of what I said above, let me add that “emotion” to me is a function of music. There’s no getting emotional over gear, unless it is one’s sole inheritance from a loved one. From my perspective, what systems “contribute” is distraction, which precludes emotion. So when a drum whack makes me almost leap out of my seat as it would in a live concert, and a tube amp slightly softens bass response, that’s nowhere as decisive as the fact that a drum whack isn’t just bass, and what hinders my emotion is inevitably when my attention is drawn to a part rather than the whole. The musical properties that let us engage with the emotional content, to me are about coherence and timing, and of course tone (which is big when one is primarily a classical music aficionado like me), apart, quite simply, from anything that doesn’t belong there (the very definition of distraction). In general, I can’t bring myself to say that tube gear or solid state does all three better than the other, the point is the tradeoff must not be such that one isn’t connecting to one’s favorite music. In a nutshell, even if I know I’ll get in trouble saying I haven’t heard as realistic a kick drum whack from a tube amp as solid state, I say so as someone who owns and loves, among other, tube smps, and since I seem to listen to an even greater proportion of classical than I used to, it may be that tone makes a greater proportion of the music I listen to nowadays speak or connect to me (rather than vice versa - if I, the listener, have to bring emotion to the table, then what would I need great gear for?). But, as I told @christoph on Sunday morning, I occasionally miss the realism of a kick drum whack as played back through a Spectral system, engaging me with a type of music I used to listen to more often but now do more rarely - that’s how our playing kick drum whacks on several systems came about. It’s partly an educated guess based on inference (I know all those systems having heard them many times), but I’ll venture to say the Triode-FET has an edge in this department, possibly because it sounds more solid state than tube to me anyways, having said that, I made sure to play some music based on tone (e.g. massed strings), and there I cannot say the scale was tipping (nor isn’t generally speaking) the same direction for me, so that’s that.

Greetings from Switzerland, David.

Hello David

You should of played with bias and /or tube rolling. The TriodeFet bias system is not like the normal bias systems in other equipment, where you have a linear scale which there is a sweetspot and you can move around it, but more like a 3d "bias"
space , that is crated by the many parameters you can change on the amp.
We do this occationally when visitors come, we can change the same amp sound from more tube-than-SS, and other way around, but also keep the punch and dynamics and add more SET characteristics.This system can really change the amp to suit the system, music and speakers.
The amp can transform it's character because you can manipulate the TriodeFet transfer curves, as they are derived by the two (or one) tube used.
When you go into tube combinations rolling, then tuning space gets a fourth dimension

Do you know what combo was used in the amps?

Best
Stavros

 

[acousticsguru]

Hello David

You should of played with bias and /or tube rolling. The TriodeFet bias system is not like the normal bias systems in other equipment, where you have a linear scale which there is a sweetspot and you can move around it, but more like a 3d "bias"
space , that is crated by the many parameters you can change on the amp.
We do this occationally when visitors come, we can change the same amp sound from more tube-than-SS, and other way around, but also keep the punch and dynamics and add more SET characteristics.This system can really change the amp to suit the system, music and speakers.
The amp can transform it's character because you can manipulate the TriodeFet transfer curves, as they are derived by the two (or one) tube used.
When you go into tube combinations rolling, then tuning space gets a fourth dimension

Do you know what combo was used in the amps?

Best
Stavros

Hi Stavros, thanks for chiming in! These are Michael’s, and he has played with bias and rolled tubes to some extent, but also mentioned there are almost too many variables for him to go through every possible combination. I’m guessing it’s as with everything, once one starts to get the gist, the decision making process is going to take less time?

I’ll ask Michael what his current favorite tubes and settings are, in the meantime, do you play with the latter depending on the recording as well, or find what works best in a given system, room and setup?

Greetings from Switzerland, David.

 

[acousticsguru]

The 211 based SET's I ordered from Sound Gate/Otomon in Japan are sent with volume pots for use sans pre-amplifier. I see that in general you preferred the sound of your system when using a pre-amplifier despite the volume pots ... that is, until you bought a DAC with an improved output stage (but still on the fence). I intend to run mine directly from my Ypsilon VPS100 phono stage. Have you any experience going pre-less with phono stages?

In other people’s systems - I don’t currently own a turntable anymore. My impression is similar to running DACs direct: phono stages that are part of a full-blown preamp into power amps (with or without input attenuators - it goes against my grain to refer to those as integrated, especially since I’ve owned several that fall into that category) are more likely to offer the requisite drive, not to mention impedance matching and overall coherence. An EMT or Spectral (back when they still made phono stages - I don’t even know most of the current portfolio) doesn’t “need” anything IMHO (these are just examples for tube and SS off the top of my head), whereas those that come without output attenuation of their own, I’d always want to try with and without preamp, just like DACs (despite the fact that most of the latter include some sort of volume control these days).

Greetings from Switzerland, David.

 

[acousticsguru]

In other people’s systems - I don’t currently own a turntable anymore. My impression is similar to running DACs direct: phono stages that are part of a full-blown preamp into power amps (with or without input attenuators - it goes against my grain to refer to those as integrated, especially since I’ve owned several that fall into that category) are more likely to offer the requisite drive, not to mention impedance matching and overall coherence. An EMT or Spectral (back when they still made phono stages - I don’t even know most of the current portfolio) doesn’t “need” anything IMHO (these are just examples for tube and SS off the top of my head), whereas those that come without output attenuation of their own, I’d always want to try with and without preamp, just like DACs (despite the fact that most of the latter include some sort of volume control these days).

Greetings from Switzerland, David.

Steve Deckert has a smart way of putting it: that an amp doesn’t “know” what comes before, so all depends on the quality of the output stage of that prior component in the chain.

Greetings from Switzerland, David.

 

[Aries Cerat]

Hi Stavros, thanks for chiming in! These are Michael’s, and he has played with bias and rolled tubes to some extent, but also mentioned there are almost too many variables for him to go through every possible combination. I’m guessing it’s as with everything, once one starts to get the gist, the decision making process is going to take less time?

I’ll ask Michael what his current favorite tubes and settings are, in the meantime, do you play with the latter depending on the recording as well, or find what works best in a given system, room and setup?

Greetings from Switzerland, David.

Hi David

The tube compliment choice (single, dual or combo) will be the first, when choosing how to better suit/alter the amp to the system (if you have tubes to play around that is).

The bias system then comes into play.
You could be right, as with everything , it is a slippery slope. Once you get the experience how you can alter the sound, it is a possibility that you will spend a lot of time tweaking, especially if you are into this sort of thing.Having too many options is confusing for some, although once you get familiar, it is very easy to do even on the fly while listening.
It is a powerful tuning system, which as everything is prone to abuse

You can certainly change the amps to better suit the recording( some labels have extremely district character which would make some sense to tune.) However i usually leave the amps alone in systems, after i settle in the tube combo used and TF current.(which be mostly determined by the room/speakers/pre ).

Regards
Stavros