Class A “class D killer” amplifier with THD less than -120dB

[Piere]

I do find class D's high-frequency distortion, even when bandlimited to well below the self oscillation (switching) frequency, curious. I would have expected loop gain to be high enough to stay competitive or better than class A/AB amps well beyond 20 kHz, unless HF artifacts are being aliased/mixed back into baseband. @pma's data are very interesting and the first I have seen in a while for audio amplifiers. I have not tried to research it though believe Bruno's papers may offer insight (?) Times like these I wish I had kept my AES membership.

Curious about that too! The class-A/B CA's I have build have a small signal BW of around 10 MHz and a full power limit of 200 KHz before slew limiting comes in at full power. Nevertheless they are limited at the input to around 150 kHz to avoid any slew induced problems. Total wideband input noise is about 4 nV/sqrt(Hz). Which calculates to -130dB for 2V_rms input at full power and 20 kHz BW.

 

[Axo1989]

Another day, another old farts thread.

I'm favourably disposed to your products for the obvious reasons (extra nice build, features and aesthetics, reasonable pricing) but dropping snark into another makers' (or potential makers, not sure) threads without a smiley is a bit off-putting. Don't Musk out on me.

 

[Ken Tajalli]

Yes, totally. Scary low efficiency. Even that big Marantz I pictured above is the equivalent of a couple of outdoor medium floodlights in Class A. Or an entire house of LED lights...

My retired monoblock class A , tube OTL's burnt nearly a kilowatt at idle!
Electricity prices went up, I retired them.
My SS amp now, pulls 20W at idle, perhaps about 30, while listening at night time.
Its a class AB.

 

[boXem]

I'm favourably disposed to your products for the obvious reasons (extra nice build, features and aesthetics, reasonable pricing) but dropping snark into another makers' (or potential makers, not sure) threads without a smiley is a bit off-putting. Don't Musk out on me.

I did not understand that this was a manufacturer thread. Sorry for this. Then the best would be to contact the admins to get the manufacturer badge. What do you think about this @pma?

 

[Blumlein 88]

Another day, another old farts thread.

Yes, that is how it looks to me. Doesn't mean some of the questions about class D aren't valid, but for some reason people fight against some new tech. CD, SS, fuel injection cars so on and so forth. Even if some good A/B units are slightly better they almost surely cost more. So question becomes are they good enough. They seem good enough. We have lots of people complaining they aren't. Yes, distortion goes up at higher frequencies. But when what goes up starts from such a low level does it mean it reaches an audible level? Does IMD dirty up the below 20 khz range enough to hear? Actually pretty simple to test these things.

 

[antcollinet]

Seriously, if you are cranking it near full power, nobody gives a chit about being green and saving the planet, do they? They are partying hard.

If I've had enough Bushmills, I can't even hear my tinnitus buzzing.

 

[AdamG]

I did not understand that this was a manufacturer thread. Sorry for this. Then the best would be to contact the admins to get the manufacturer badge. What do you think about this @pma?

No one here other than you has made a notification they are a Manufacturer or Vendor. So, if you are please advise us before you do anything more in regards to promoting your product here. Thank you for your understanding and cooperation.

 

[AdamG]

And I think we have enough Kill Class D Threads for now thank you. Any further thread creations along this line will be closed or merged. Popping up like weeds recently!

On Edit. I changed my mind. We have too many similar yet separate threads about this same subject. So I merged them here. Good reading!