Class A amplifier

[Goodman]

The Stellar M1200? -



The BHK Mono 300:


If we are talking about a company's "best products" - well, PS Audio prefer tube input buffers. A MOSFET buffer is used on their cheaper amps.

For reference:
Review and Measurements of PS Audio S300 PWR Amp | Audio Science Review (ASR) Forum

This one with the MOSFET input stage is a recommended product here! The other power amps show "good enough" performance when measured elsewhere, no matter the topology. (The less said about PS Audio preamps and DACs, the better).

The class D modules they use may change frequency response with low impedance speakers, so it would not be a surprise if their MOSFET power stages are superior. Neither range is necessarily suitable for very low impedance loads, if you skip the marketing blurb and go straight to the specs, but I don't have any real problem with that.

So, if we limit ourselves to PS Audio I'd expect your assertion that they would claim their non-class D amp to be superior, to hold. It doesn't for Marantz though, and "I haven't owned one" doesn't cut it as a way out;

Glad we could agree an the PS audio class D.
On Marantz, I never mentioned them, you did, I meant I don't know anything about their products; do they rate their class D above their other POWER amps? Good to know, although marketing could be involved.
Obviously you are in the measurement objectiviste camp. So, are you saying that a good Class D amplifier will out perform any class AB amp on any load (my speakers) no need to listen or compare. There seems to be a consensus of reviewers and end users, (me) that Class D amps sound detailed, transparent but "thin," anémique in the lower midrange, and lacking weight. Are we all half death or inhabited with exorcism?

 

[JSmith]

Are we all half death or inhabited with exorcism?

Nah, your just likely finally listening to a transparent system that plays the source for what it is, rather than something which has a warm or coloured sound. This can be achieved via DSP/EQ, it doesn't need to be baked into the amp so it can't be altered. It's also very weird to classify all amps of a particular topology type as having a certain sound, when there are many types all with different measurement profiles.


JSmith

 

[SIY]

Glad we could agree an the PS audio class D.
On Marantz, I never mentioned them, you did, I meant I don't know anything about their products; do they rate their class D above their other POWER amps? Good to know, although marketing could be involved.
Obviously you are in the measurement objectiviste camp. So, are you saying that a good Class D amplifier will out perform any class AB amp on any load (my speakers) no need to listen or compare. There seems to be a consensus of reviewers and end users, (me) that Class D amps sound detailed, transparent but "thin," anémique in the lower midrange, and lacking weight. Are we all half death or inhabited with exorcism?

The best AB amps I've ever tested were ALMOST as good as the best Class D amps. No difference in sound, of course.

What you're "inhabited" with is peeking. When you compare level-matched and double blind, you will undoubtedly find that your sighted perceptions were misleading. Then you can either adjust your thinking or (sadly too common) focus your creativity is making excuses about why you have to peek to do sonic evaluation.

 

[Galliardist]

Glad we could agree an the PS audio class D.
On Marantz, I never mentioned them, you did, I meant I don't know anything about their products; do they rate their class D above their other POWER amps? Good to know, although marketing could be involved.
Obviously you are in the measurement objectiviste camp. So, are you saying that a good Class D amplifier will out perform any class AB amp on any load (my speakers) no need to listen or compare. There seems to be a consensus of reviewers and end users, (me) that Class D amps sound detailed, transparent but "thin," anémique in the lower midrange, and lacking weight. Are we all half death or inhabited with exorcism?

Clearly, your reference to "POWER" amps shows that you DO know the Marantz range - you are setting up your next get-out, because their reference and high end class D amps are integrated. You didn't specify power amps until this last post. No, you don't get out of your incorrect comments that way here. Bad luck.

Speaking of which, your attitude to PS Audio - you don't recommend MOSFET or class D amps, so I don't see how we agree, since in the right setup I would be happy to live with any of the PS Audio power amps, with another company's suitable preamps and DACs. You clearly don't recommend either MOSFET or Class D on principle, though, so you wouldn't. What's your point, that one amp you consider bad is better than another amp you consider bad?

And that brings me to your allegation. I'm class agnostic and believe in the use case. We have to start with the speaker/room interface, which will dominate the sound. Then choose an amp that will drive the speakers adequately. There's no reason in my opinion not to use a source that measures well, though I see no reason to only choose the "best" measuring. In fact, while I do, obviously, value decent measuring equipment, I actually believe that chasing "the best sounding" to the extreme is self-defeating. I happen to own the Marantz MA-10 - it has a bridged class D power stage that may not drive very low impedances (which I don't need). Does that make it a bad amp? It's a suitable amp for my use case.

As far as "weight" in the bass goes, I don't value it that greatly. I listen to early music (you might have guessed) and ensembles may have several different bass instruments playing. A good system allows me to hear what each of those instruments is doing. Is that what you mean by "lean"? My old AB amp was equally good at it. And I've heard far too many systems mess that up...

 

[Mart68]

on another forum a Martin Logan user has his valve amps go faulty. Whilst they were away for repair he substituted some Nord Class D amps.

He posted that he was not happy with the 'lean and clinical sound', but was told 'That's the character of class D mate.'

Then he remembered that he had dialled back the bass level on the Martin Logans to get rid of some bloat that was present with the valve amps. He adjusted that back to the default, and the 'lean and clinical' sound was no more.

Jumping to conclusions based on the nonsense written by reviewers and 'users' is always a bad idea and can be expensive.

Most reviewers and users don't know their arse from their elbow.

 

[BDWoody]

What's wrong with turntables?

Nothing at all.

It's more about the expectations many have based on a lot of mythology surrounding the medium in general.

There seems to be a consensus of reviewers and end users, (me) that Class D amps sound detailed, transparent but "thin," anémique in the lower midrange, and lacking weight. Are we all half death or inhabited with exorcism?

No, just drawing drawing erroneous conclusions based on uncontrolled listening.

Bias is a real thing.

 

[Deleted member 43441]

A class A amp is not going to be technically a step up from a class A/B one, and in fact will undoubtedly measure worse. Going from A/B to A is a more lateral move which is starting to get into the 'audiophile' side of things, more subjectively based. Nothing wrong with that at all, but you will be wading into a pool with strong viewpoints either way, subjective and objective, with just one the 'right' way according to who you listen to.

So, in my opinion, there is no need to go with class A. But if you want to explore alternatives, even if they bring you right back to the same place, by all means, go for it. Its supposed to be fun.

I have to agree with this, and in my opinion if done correctly all of the amplifier topologies sound similar… if not indistinguishable.

I have newer Pascal class D amps, and I have 30-year-old (serviced) class A/B amps, and blindfolded I’d be hard-pressed to pick which one is playing.

 

[Purité Audio]

Same here compared every known class as long as the amp is properly engineered and capable of driving the loudspeaker.
Keith

 

[Deleted member 43441]

This is what people need to understand, and your statement is exactly right… If properly done they are basically indistinguishable, I know this because I’ve had many of them. The terms that are thrown around (online) these days are not electrical, and surely not scientific terms. They lead to misinformation, and people chasing a magic bullet.

 

[Purité Audio]

They would all be better off acoustically measuring their rooms, no dealer margin in that of course.
Keith

 

[Deleted member 43441]

They would all be better off acoustically measuring their rooms, no dealer margin in that of course.
Keith

Isn’t that the truth! How many times do I see equipment that measures so great, in a room that sounds like an echo chamber? People would be better off spending a reasonable amount of money, and investing in base traps and wall treatments… than spending a fortune on electronics aone.

 

[Deleted member 43441]

Same here compared every known class as long as the amp is properly engineered and capable of driving the loudspeaker.
Keith

That’s quite the statement from a manufacturer, I appreciate your candidness! What a great statement.

 

[Purité Audio]

Did you see the in-room measurements for the Magico M9 before they were taken down?
As scotty would have said you can’t refute physics captain or something like that.
Keith

 

[Purité Audio]

That’s quite the statement from a manufacturer, I appreciate your candidness! What a great statement.

I am only a flogger, I don’t have the wit to actually make anything, I do write with suggestions to manufacturers from time to time they have more or less all been universally ignored.
Keith

 

[Deleted member 43441]

Did you see the in-room measurements for the Magico M9 before they were taken down?
As scotty would have said you can’t refute physics captain or something like that.
Keith

I did not see the measurements. I only signed up yesterday evening.

 

[Deleted member 43441]

I am only a flogger, I don’t have the wit to actually make anything, I do write with suggestions to manufacturers from time to time they have more or less all been universally ignored.
Keith

Don’t forget, it will sink in to the ones that want to hear.

 

[Purité Audio]

I did not see the measurements. I only signed up yesterday evening.

Welcome, despite being a hotbed for evangelical measurement fanaticism it can occasionally be pretty enjoyable here.
Keith

 

[RichB]

You choosing who the Ferrari is and who the Chevrolet is without scientific measurements / method - highly subjective.
From science' POV, none of the brands you posted (10k$ amps) come close to a 3k$ class D amp from Benchmark (AHB2). Read the measurements and compare.
The way I see it:
Ferrari = Benchmark AHB2 (class D) and the amps that measure well
Chevrolet = audiophile BS that doesn't even have clear measurements posted by manufacturer

Back to the thread:
@rman9 IMO your system is fine. Enjoy the music and apply room correction if you can. No need for new stuff other then room correction IMO. (I agree with @Galliardist )

The AHB2 is a class A/B amplifier with feed-forward correction from a low powered class-A amplifier. It also uses feedback and a switching mode power supply. It claims to have negligible crossover distortion. I obviously like them

With music and HT, I frequently listen at levels that do not exceed 1 watt (measured using 0 dBFS signals and voltmeter). In reality, problably 1/10'th of a watt.

- Rich

 

[Goodman]

I have to agree with this, and in my opinion if done correctly all of the amplifier topologies sound similar… if not indistinguishable.

I have newer Pascal class D amps, and I have 30-year-old (serviced) class A/B amps, and blindfolded I’d be hard-pressed to pick which one is playing.

On what speakers?

 

[RichB]

@Amir has done square wave testing but it doesn't show anything that is not in the other measurements so he doesn't do them any more. No amp can reproduce a "perfect square waves" as you would need unlimited bandwidth. The best use of a square wave is when doing repair on an amp... a quick look at a square wave can give you a lot of information on where to look for the problem.

I'd like to see dynamic transient power measurements rather than fixed power bandwidth square-waves or similar measurements.
Protection mechanisms differ it would be interesting to see if these, and other design choices, affect cause linearity or distortion issues when driving reactive loads.

- Rich