[sdiy] ot: class d audio amp

[Czech Martin]

Yes, it is basically amplifiers going to DAC.
For subwoofer service the distortions can be quite low,
lower than 1%, down to 0.1%.
And with good efficiency.

m.c.

> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl
> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Glen
> Sent: Montag, 20. Oktober 2003 16:37
> To: Cornutt, David K; Sdiy (E-mail)
> Subject: RE: [sdiy] ot: class d audio amp
> 
> 
> At 10:26 AM 10/20/03 , Cornutt, David K wrote:
> 
> >Bleagh.  Isn't class D one of the circuits that they use
> >for RF amps, that only amplify part of the waveform?
> >I don't think I've ever heard of anyone using one as
> >an audio amp.
> 
> The "D" is for "Digital" in this case. 
> 
> I saw a very old article once about building a class D amp 
> with 555 timers
> and some support circuitry. I believe it used PWM of a high frequency
> square wave, filtered the result, and then sent it to a 
> speaker. It was
> supposed to be pretty power-efficient, and suitable for 
> battery power. Of
> course, this particular circuit wasn't meant to be Hi-Fi, but 
> I have heard
> of other class D audio amps that were supposed to give good quality. 
> 
> Come to think of it, a 1-bit DAC is pretty much the same 
> idea, albeit at a
> lower power level, if I'm not mistaken. I would certainly 
> consider that a
> usable level of audio fidelity.
> 
> later,
> Glen Berry
> 
>