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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
georgehifi's avatar
georgehifi
4,966 posts
 
You ricevs are doing the same here that  audiotroy is doing over here 
https://forum.audiogon.com/posts/1676235
erik_squires
5,268 posts
 
Sorry, but we wouldn't even be having this discussion if great class D amps had been around for ages.

Judging by the measurements I keep seeing, great class D amps still haven't arrived.

That's the first mistake.

Look, I use technology a lot. A LOT!

I believe in it, but I also know the limitations. It is one thing to measure distortion given our most common measures:
TIM and THD+N
They may tell us very little about how this is perceived or how it affects music reproduction to the human ear/brain/pleasure centers. I can critique practically ANY amplifier to death.

And also, take a look at some of the most highly touted amps out there. They aren't exactly stellar spec performers.

My point: Human beings perceive sound differently than pure specmanship. If you want to go "by spec alone" then you really can't make any claims at all.  I'd argue that based on the literature, some Class D are excellent amps and no one can hear better. 
My point? Your own ears are FAR better judges of quality and pleasure. Find me a measure that compares pleasure to transistor speed and I'll be really interested, but claiming that there's X parameter that Class D amps have to overcome before you admit they are excellent is hard for me to accept.

Do you know what I cannot argue against? People saying "I heard Class D amps by X manufacturer, and I did not like them because they sounded like ..."

That's fine.

But me? I've heard great Class A amps from highly touted makers and I preferred Class D.

And here we are back to my overall thesis:


Buy what you like listening to, specs and other people's opinions be damned. It's your wallet, and your time on earth that is important. No specs, no transistor speed, no class (A/B/D) matters when it comes time to spend your money. Make yourself happy.
What I lack, is a belief that a specific set of technical specs can be made so much better in Class D that they would change everything. Sorry, I like what I have. Show me not the spec but the performance and I may want more.

Please, buy what your ears like.
Best,
E




kosst_amojan
2,095 posts
 
Look at the measurements! It's more than just the noise. I haven't seen one yet that doesn't ring. They all have a lot of horrible things going on and it's a process of compromise and trade off to get something that sorta measures ok and doesn't sound simply bad. 

What's more, I reject the wholesale dismissal of measurements. It's a very sad state of affairs that most listeners are clueless about what's in the boxes they buy. "Just buy what you like listening to" is how Bose got so big. Most people LIKE compressed dynamics and overblown bass. Is that what hifi is now? That is why Bose has used class D amps for ages now. That's what class D amps do very well. 

Measurements are extremely useful for estimating what an amplifier will do with a pair of speakers. They are good indicators of how the thing will sound. How are you supposed to "buy what you like" if you don't even know what it is you like? "I like amps with ungodly noise and ringing" said nobody ever. "I like quiet, simple, linear, wide bandwidth amps with sexy negative phase second harmonics" says this guy. Which class D does that? I'm not interested in anything else. 
Post removed 
ricevs
190 posts
 

I am glad you know what you like. However, you are just guessing. You have never heard class D......so what do you have to contribute here? Just the same old "I don’t like how they measure, so they must not be any good". The fact is, that many have abandoned their class A/B, class A and tube amps for class D amps. This is a fact. I would never say that class D is better than any other class.....but in the last 5 year it has matured to be an equal competitor.

My own designed dual mono stereo 25 watt class A amp is very much like the Pass F5, except it uses dual differential pairs in the front end instead of just 2 jfets. The output stage is 3 parallel push pull mosfets and single feedback to the differential stage. 1.6 amps bias, only two resistors in series with the signal, DC coupled, no compensation, no current limiting, no binding posts (hardwired), 500 watt Plitron transformer for each channel, tons of power supply caps bypassed with modded Wimas, PCOCC wiring, damping of heatsinks and boards, no steel plates on transformers, no fuse, etc, etc. It sounds really, really great. But my modded IceEdge modules sound better. Now I am rebuilding the class A amp so it is in two chassis (the power transformers were interacting and to close to the circuit) and using even better resistors and wire and hopefully it now can compete or even beat my class D amp. We shall see. However, I could never produce the amp as it has no protection and who wants a 25 watt class A amp when you can get a 600 watt amp that sounds as good for less money and uses little heat and has an output impedance under 10 milliohm and input impedance of 150K!?!

If you go to Audio circle and go to the Nuprime circle and click on the thread on the Evolution One amps you will find a link to a review of their amp on Hifi-advice that is an interesting look at class D and its history.  For some reason I cannot put here the link to the review.  Worth reading.


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