New Digital Switching Amplifiers

What would it - high freq hash above 20k - sound like over speakers?

Bob Wood
http://www.GreatHomeTheater.com

Thanks Ar_t.
Bob, I don't think there is any sound you can hear over 20k but purely subjectively, it gives me a headache. Just don't ask me to DBT my experience.

Personally I dislike the entire working principle of digital amps
(aka class D,PWM).
First of all the introduction of a convertor into the signal chain
(converts the analog signal into a pulse-width modulated one),
then the fact that the transistors only ever are fully off or fully on
and in the full on only transmit white noise.
That the re-conversion relies on the inertia of the connected drivers.
The high-power fast switching limits choice of transistors to VFets.
Radio interference created by the switching and frequency,harmonic and intermodulation distortions created by the modulator (convertor).

The only reason for their existence is that they are very light and cheap
compared to regular amps which makes them ideal for touring pa application.
They are just about good enough for the job.

By the way switching frequency and amplitude is fixed in all these amps
as their functioning depends on it.

[email protected] switching frequency is not fixed in Tripath-based amps, and some others. Your understanding of digital amps is dated in other respects too. As to their advantages, light weight is not important for home audio, but low cost certainly is.

I agree. I believe he is assuming that this genre of amps has not improved any in the last 20 years.

It has.......I wouldn't waste my time with them if they hadn't.

As for "conversion".........some types do. The PCM/PWM ones do. Mostly, they just modulate the power supply, which is all that any amp does to begin with. It is just a different form of modulation.

I do not understand how they "only transmit white noise". Waiting for an explanation on that one. RFI, yes they do produce that. Some of us go to great lengths to eliminate it.

As for "cheap". Yes, some are. About the only real cost eliminated is the heat sink. You can get by with a smaller power transformer, as you don't have to heat the atmosphere at idle. Other than that, they are not that much cheaper to build.

Well, the goods ones aren't........