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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
mr_m
1,087 posts
 
Class D is definitely the future of audio. And they will only get better. Heat reeks havoc with amp internals. Class A is not immune to this not to mention draws large amounts of current even at idle.
twoleftears's avatar
twoleftears
1,457 posts
 

I heard Linear Tube Audio preamp + Bel Canto Ref 600 recently, and together they sounded very good.

True audiophilia, on the other hand, involves a certain measure of necessary sufferint.  Class A without a/c in the summer; needed to hire moving people every time you rearrange your listening room, etc.

kosst_amojan
2,095 posts
 
@aberyclark 

No, not really. The ONLY downside to class A amps is that they're obscenely inefficient and as a result make ungodly amounts of heat. Other than that they're technically superior in every way. 

Transistors make a lot of garbage when you go switching them fully off. That's why you apply a little bit of bias to a class AB amp. Otherwise it's just 2 class B amps with a ton of distortion. Class D doesn't bias the transistors at all and switches them at very high frequencies and that creates huge amounts of noise and distortion. The output of a class D module then needs to be filtered extensively to block the huge amount of high frequency noise and smooth the notchy sort of output into something resembling a waveform. 

The major advance in class D is stitching the transistors on and off even faster to achieve finer granularity in the pulsed output. That makes it easier to filter. Filtering isn't really advancing all that much. That technology has existed for a long time. It's just a debate of how to best apply it to this problem. 

I, and many others, think simple, linear signal chains from the source to the speaker sound best. It's really hard to beat a class A amp with a nice, clean, low level, low and even order distortion character. That's very hard to do with class D. 

mapman's avatar
mapman
15,679 posts
 
Kosst so what Class D amp setups have you actually  heard?  What other  set ups are you comparing to?  


tomic601's avatar
tomic601
2,164 posts
 
I have heard both the ARC monoblock 450 wpc and stereo class D amps (225 wpc )with a REF5 , source was TT , Ayre CD player, AQ cables and Vandersteen 7 at HiFi buys ( at that time 2013 Audio Alternative)
other amps auditioned that day over a 9 hour period:
Aesthetix Atlas - Stereo
Ayre MXR
ARC Ref150
ARC HD220

while the ARC class D amps finished last ( I ended up buying an Ayre VXR, they put up a good account of themselves. Not the last word in refinement, smoothness, etc....they are relatively inexpensive and don’t require a long term care contract with a chiropractor

i suspect ARC and others will keep pushing the quality and refinement for obvious reasons.....as they should...just as the best more traditional circuit designers will also keep pushing, as they should.....
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