Class A amps or Class D??: Which sounds better??


Amplifier performance and synergy depends on the other components, and cables in a system. I have read alot about the advantages of Class A.amps Though an older amp design, do class A amps necessarily sound better than Class D digital amps like Nu-Force, Bel Canto, and Wyred4Sound?? These class D amps supposedly run more efficiently, with less heat and noise and are smaller in size.

I have a friend who has a Musical Fidelity A3CR power amp and a Bel canto pre-amp, and a pair of Spendor floorstanders. The MF amp is at least 10 years old, and no longer made. I have listened to the amp in his system, and it does sound very good. Most noteably is its across the board smoothness. However, I think its performance is system dependent, and might be a liability in other systems. Would like to hear comments and opinions about these two amp "designs", and if one sounds better than the other, OR JUST DIFFERENT.

BTW, I am not sure that owning a 10 year old amp like the MF A3CR is a good idea, despite its class A rating, and a few positive consumer reviews I have seen. Thank you
sunnyjim
My personal preference is for Class A, having just switched from D to A. Despite the much lower rated power, I found the Class A amp to have greater definition, control and musicality.
"..lack of authority that class D brings to the party is obvious "

What about vehicles with internal combusion engines ???
Once I drove Yugo and its was horrible !!!!!!! Friend recommended Ferrari but I said "Thanks but no, I know how they drive!"

The "authority" is a function of well designed power supplies be it for class D or class XYZ with BIG, BAD, headroom (and NO distortions, pleeeease!)

I piblished article on the topic in Enjoy The Sound:

http://www.enjoythemusic.com/magazine/manufacture/0708/index.html

If interested in the topic - please read, I wrote it as educational tool for non-engineers music lovers.

All The Best,
Simon
"It boils down to having the right tool for the job."

Thank you for that answer that "hits the nail on the head".

What hammer works best? Screwdriver? Amplifier?

Audio is not so complicated anymore as some make it out to be. The basic problems have been solved for years.

Now it is exactly more about choosing the right tool for the job than ever because, guess what, there are many very good ones out there and they are all different! Go figure!

Of course some may like certain tools and build their solutions that way. No problem. Its all good! There is no better or best technology. IT ALL DEPENDS! Who'da Thunkit?

One needs to think twice before categorically dismissing certain technologies that they may not prefer because there may be others out there that know better and credibility is lost.
I've been playing Upright and Slab Bass professionally since 1965. Playing in the rhythm section means you have the largest gear to deal with. I own and have owned a great deal of instrument amplification over the years. It boils down to having the right tool for the job. Often I need to transport my fiddle, amplifier and cabinet, in one trip to and from the car. A 90 pound Ampeg SVT head is out of the question.

I too play string bass, and in my band I play keyboards. Our bass player uses a 400-watt vacuum-tube Peavey, I have moved the amp many times and am well aware of its weight! We did a comparison between it and the 500-watt Orange class D amplifier; despite having 100 watts less power there was no contest- the Peavey smoked the class D amp easily and I have seen it do that a lot.

But I understand fully the issues of weight and heat! If we are to compare apples to apples, I recommend that the class D amp have the same power as the class A amp it is compared to. I think anyone will see at that point the difference in authority. However, class D represents the cheapest power available, and IME what that means is to have good success with the class D, it needs to have a lot more power- IME about 2-3x more at least.

Class D amps are highly power efficient, as the output section switches on and off and so does not spend much time in the linear region. This keeps heat down, and the requirement for large heatsinks and power supplies.

If you play organ pedal tones on your system at lifelike levels, this is the sort of signal that will tax a class D amp as it will heat up and where its sonic weaknesses will be manifest. IOW, something that makes serious on-going power requirements of the amp. With a class A amp this is no problem but a class D amp of the same power will get into trouble and its easy to hear.

My recommendation for those who doubt me is to do the comparison- but in doing so make sure that both amps make the same power.

I have seen Class D as the rising star in high end audio for the last 10-12 years and we've been listening to them ever since they first appeared. I think the technology still has a way to go- if you look at price/performance curves you will see what I mean.

In the meantime, the best I can make out is that to make class D work, it is better to have the amplifier be a lot more powerful than you have expectation of needing. That way you are not taxing it an it can show itself off better. But if you are talking apples to apples its a different matter.

I do not agree that my 1st caveat is somehow contradictory to my prior points in my post above. An 8 ohm speaker is sufficient for demonstration. Now with regards to 'difficult' loads, there is a reason that such speakers are said to be difficult. Its not just that some amps won't be able do drive them- its a lot more than that. Its a simple fact that you can see in the specs of any amplifier- class D included- the lower the impedance and the harder to drive the speaker is, the more distortion. In transistor amplifiers and class D, this means you will hear more odd-ordered harmonics, which the ear translates as harshness. So while an amplifier may be able to drive a 'difficult' load, this is not the same as saying it is sounding its best. So my caveat is perfectly acceptable.