Class D come of age - Coherent amplification

[Clive]

I'd be very interested to hear Tony's class d amp. I identify with what he's saying when comparing valve and class d. I find I cycle through a few power amps to give me a variation in the sound I experience. There are a few more amps in my stash than my signature suggests. The favourites however are the class d and the two valve amps. I select the class d for a few weeks when I'm craving a tighter, more "precise" sound, after those few weeks I then switch to valves to give me some extra meat to the soundstage and that fluidity Tony talks about. The valves being SE and PSE will be euphonic but they sound good and my speakers are a great match for them. Again...after a while a want to switch the presentation again so I revert to class d, sometimes via class a/b solidstate Philips Black Tulip or current dumping Quad 306.

If I could finally have all the positive attributes in a single amp it would be wonderful.

[Marco]

Hi Tony,

Interesting stuff, as is Alan's appraisal of the Class D amps in question. I have little experience of Class D, so can't really offer much input to the discussion. However, were Class D amps used in the system you demonstrated at Cranage Hall last year?

As you know, I spent some time in your room listening to music and chatting with you, so if that was Class D I may have some kind of handle on what it does, musically

Marco.

[Pharos]

Are my now ten year old class D Icepower amps regarded as not very good then?

[Mr. C]

Dennis,

In answer to your question, if they are ICE power 1000ASP modules they have a limited bandwidth of 38Khz +/-3dB so not even the second harmonic is captured.
From personal experience with a wide range of amplifiers, a minimum BW of the four harmonic (80Khz) more is better but having over 1/4 mhz is a bit OTT is required to begin to truly recreate a proper three dimensional, textural layering imho.

The later ASX series are a big improvement over the ASP models which were really for pro audio big banger speakers and subs. Though the 500 ASP I always felt far more engaging even only if it had 500watts lol still swing 38 amps at peak, but it had a 80Khz bandwidth.

Everyone experience with these may well be different, however the bottom line is what each of us really holds close to their heart for perception of a quality sound.


The

[Marco]

Hi Tony,

Could you answer post #22 please, specifically whether it was Class D amps I was listening to in your room at Cranage? Churz!

Marco.

[Pharos]

I cannot see the need for the bandwidth you quote Tony.

[montesquieu]

Dennis,

In answer to your question, if they are ICE power 1000ASP modules they have a limited bandwidth of 38Khz +/-3dB so not even the second harmonic is captured.
From personal experience with a wide range of amplifiers, a minimum BW of the four harmonic (80Khz) more is better but having over 1/4 mhz is a bit OTT is required to begin to truly recreate a proper three dimensional, textural layering imho.

The later ASX series are a big improvement over the ASP models which were really for pro audio big banger speakers and subs. Though the 500 ASP I always felt far more engaging even only if it had 500watts lol still swing 38 amps at peak, but it had a 80Khz bandwidth.

Everyone experience with these may well be different, however the bottom line is what each of us really holds close to their heart for perception of a quality sound.


The

In agreement with Geoff that Class D is undoubtedly the future, my concern has been that any I've heard have been close, but not quite up to the best valve amps in terms of musicality. (My view is that the best Class D amps have probably already exceeded what A or A/B solid state can manage). So still 'the future' then even if it's getting nearer.

Tony, can you give us a view on price? £140k amps of the kind you mentioned as competition aren't real world for people here, any more than they are likely to drive home in a Bugatti.

The biggest question really is 'what's the damage?' which for many will determine whether a listen is something urgent or a curiosity that can wait till some random hifi show.

[sq225917]

I cannot see the need for the bandwidth you quote Tony.

Maybe there's a benefit to having a faster modulator which has shorter clocking cycles and therefore greater precision, the converse of course is a greater requirement on the output filter to block all HF EMI reaching the speaker.


Tom, my experience of Class D amps says they haven't reached the best of class A/B yet. Back to back with perfectly built NC400's a I ended up going for the Class A/B unit. Of course there may be gains to be had from better input buufers and output filters for the NC400s

[struth]

In agreement with Geoff that Class D is undoubtedly the future, my concern has been that any I've heard have been close, but not quite up to the best valve amps in terms of musicality. (My view is that the best Class D amps have probably already exceeded what A or A/B solid state can manage). So still 'the future' then even if it's getting nearer.

Tony, can you give us a view on price? £140k amps of the kind you mentioned as competition aren't real world for people here, any more than they are likely to drive home in a Bugatti.

The biggest question really is 'what's the damage?' which for many will determine whether a listen is something urgent or a curiosity that can wait till some random hifi show.

Indeed many Hifi items have a higher than Hifi price tag. But plenty seem to afford them. They just generally don't frequent fora lol.

[montesquieu]

Indeed many Hifi items have a higher than Hifi price tag. But plenty seem to afford them. They just generally don't frequent fora lol.

Too busy running hedge funds, out shooting with Jackie Stewart or flying their own private jets I suppose.