1. Home
  2. amps-preamps
  3. 140387-15288

The Future of Audio Amplification

I have recently paired an Audio Research DS225 Class D amplifier with an Audio Research tube preamplifier (SP8 mkii). I cannot believe how wonderful and lifelike my music sounds. The DS225 replaced an Audio Research SD135 Class AB amplifier. Perhaps the SD135 is just not as good as some of the better quality amps that are out there, but it got me thinking that amazingly wonderful sonance can be achieved with a tubed pre and Class D amp. I have a hunch that as more people experience this combination, it will likely catch on and become the future path of many, if not most audiophile systems. It is interesting that Audio Research has been at the forefront of this development.
distortions
atmasphere's avatar
atmasphere
7,068 posts
 
@fsonicsmith
If you get a chance, look into the Tour Divide Race, from Banff to Antelope Wells.
@vt4c
+1
kosst_amojan
2,095 posts
 
@mr_m 

I don't think so. Measurements reflect it. If you listen to half way sensitive speakers, 90dB/watt or better, .02% high order distortion is going to be problematic. 
mr_m
1,087 posts
 
Kosst,
My last post wasn't directed at you, but more of a dismissal of class D as being worthless. Not in so many words by some, but I think one can read between the lines.

Looking back on what I said about 10% distortion isn't quite accurate, but some of these tube amps show just a handful of watts being useful up to about 1% distortion and this distortion rises quite rapidly as output goes up. With 10% being a approx. figure getting near these amps rated output. I don't know how you feel, but to me 1% or higher at a handful of watts output doesn't translate into very good performance, at least as far as I'm concerned....
kosst_amojan
2,095 posts
 
@mr_m 

The kind of distortion is extremely important. 1% being composed of a nice, clean second harmonic isn't good in my opinion, not because it doesn't sound good, but rather because you're basically using the amp as a tone control. That's significant color to add to a signal. That's not to say it sounds bad. A lot of people want that kind and level of coloration. Nobody likes complicated distortion. Some fuggly mix of 5th, 6th, and 7th order distortion at .1% is going to be a lot more offensive than a big, pretty 2nd order at 1%. The kind of distortion is more important than the amount. 

The problems you see in class D are the same you have with class B. The lower the power output, the more the distortion dominates. Class D just tries to minimize the distortion by reducing the time the transistors transition from off to on by pulsing them very rapidly. But no matter what, transistors switching off and on will always make huge amounts of high order distortion. It's unavoidable. It's just imppossible to fully filter it out. If it were possible, it would have been applied to class B amps by now. 
Post removed 
More to discover