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

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.

Strength of Class D is when lots of power is needed in a small and perhaps affordable low maintenance package.

Class D may or may not be a good option in other cases, however those will be weaker cases for Class D ie cases where the unique aspects of Class D do not matter as much.

What the best option is largely depends on the playing field. Each approach is sound and can sound very good on its home field, less so playing away games on the others, so one can always set pre-conditions that favor one solution versus another. What happens and is needed in real life is all that matters in the end.

I'd love to hear the NCore class D amps. I had a Hypex based class D amp as well as the lower powered Red Dragon M100 monoblocks and I just found I enjoyed Class A and Class AB amps more. The Class D amps I had seemed to lack definition and the music in my system wasn't as open or airy. I believe it is just preference and the synergy with one's equipment in their system.

I'd suggest that rather than just comparing Class D amps with Class A amps of the same power levels, compare them at the same price points, or for those that need to regularly transport their amps, the same sizes and weights, or any combinations there in.

Blah blah, and, of course, blah. Isn't this question (at least the subjective qualitative opinions part) like asking, "What's better...6 cylinder cars or 8 cylinder cars?" If the only thing defining an amp is its operating class, the world is too simple and I want off.