Class D is just Dandy!

Check out this review:

http://www.enjoythemusic.com/magazine/equipment/0220/AGD_The_Audion_GaNTube_Monoblocks_Review.htm

He loves them...bought them...replaced his tube amp.

AGD says they are using the IRS20957S PWM driver chip ($2.01@100).....and probably then a pair of $1.05@ GaNs on the output.  You can see most of the circuit inside the tube in the above review.  This means anyone can do this for practically nothing.  Putting the circuit in a tube is just a gimmick.  If they put that board inside the box and it was made in China with all the very same parts it would sell for around $1000 for the pair of mono blocks....no kidding   AGD are using LM4562 op amps ($1.00 each) on the input. There are no expensive parts in this amp.  You can see the very good sounding inexpensive Wima caps and Nichicon caps.  

But we don't want to wait for the Chinese version that sounds as good for $1000......no, let's buy the one with the board in a tube for $7000......heck, we have money to burn.....he he.  You see, fun times for cheap are right around the corner.  Of course, anyone can make an amp similar to this....if someone else here is the US made it and sold it direct....probably $2500 the pair.....still...way less than $7K.

@ricevs why don’t you do it? (No sarcasm)

Would require more technical ability and energy than I have and my health could be better (I will leave the amp making to the younger guns) .....but mostly I am writing a book that hopefully will make more difference in the happiness of people than a better inexpensive power amp.  I want everyone to be happy!

     I also have high expectations for the use of faster switching GaN  output transistors in class D amps since they have the potential to eliminate dead-time, which even further reduces distortion, which in turn,  typically results in improved sound quality. 
     I've been using good quality class D amps in my combo music and HT system for almost 6 years now.  In my opinion, they're the best option for attaining hi-end amp performance quality at an affordable price.  
     In my experiences with good quality class D amps, I've discovered their most unique quality is that they have no sound qualities of their own.  They just faithfully amplify the inputted signal without adding or subtracting anything.  They're like the audio amp ideal of a "straight wire with gain".
     Due to this extreme neutrality of class D amps, I've come to the conclusion that the most important factor determining the overall sound quality level of a system utilizing a good quality class D amp is the sound qualities of the preamp  chosen to pair with it. This neutrality also means the overall system sound quality contributions made by source components, and even interconnect and power cables,  will be readily apparent and need to be chosen carefully, too.
     I've not yet listened to a class D amp utilizing the much faster switching GaN transistors but am looking forward to doing so, hopefully, at an affordable price.  Based on my experiences with good quality class D amps, however, I suspect the use of GaN transistors will result in these amps being among the most neutral ever produced.  Choose your preamp, source components, interconnect and power cables appropriately.

Tim

,l with In my experiences with good quality class D ampsThey just faithfully amplify the inputted signaout adding or subtracting anything. They’re like the audio amp ideal of a "straight wire with gain".

Sorry they don’t look the same, just look at any 1-10khz test shot of input v output wave form.
And then without their output filter, the input wave form will be unrecognizable from the output, because of the HF garbage, and melt your tweeters silently in a nano second.

It’s like a customers preamp I had to work on, the owner said it sounded little bit hard, a quick look on the scope showed the output wave form looked just like the input wave form, all looked fine?.

Then I looked with the scope in the center of the preamps circuit, and found the wave form unrecognizable from the input with the amount of hf garbage on it.
That center amplification stage was oscillating its brains out!!! And all they (manufacturer) did was to filter it out at the end stage, instead of fixing the source of the problem.

I compensated the center stage so it didn’t oscillate anymore and removed the end stage output filter, and the customer was happy.

But you can’t do this with Class-D, so the only thing to do is to raise the sw noise in it even higher (1.5mhz) so then the output filter then can do it’s job fully without any phase effects down into the audible frequencies.
Then a Class-D’s input wave form will be much closer to matching it’s output wave form.  "straight wire with gain"


Cheers George