[sdiy] ot: class d audio amp

[Czech Martin]

No, it seems that by clever signal processing
you can get rid of a lot of artefacts,
thus delivering quite good sound at least for 
woofers (in the Nx 100W area).
When the needed frequencies get higher, the
distortion (or sideband) problems get worse.

This seems to need a lot of DSP computing.
I'm looking for the range 20Hz-100Hz, where
the problems are smaller and a PWM solution
of 1st or second order migh suffice.

I wonder if some of these devices are not
jamming transmitters ...
so officials will stop you from running them
because of EMI.

m.c.

> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl
> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Harry 
> Bissell Jr
> Sent: Montag, 20. Oktober 2003 18:13
> To: Magnus Danielson; david.k.cornutt at boeing.com
> Cc: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] ot: class d audio amp
> 
> 
> 
> --- Magnus Danielson <cfmd at swipnet.se> wrote:
> 
> > You don't want to know what class D is!
> > 
> > Cheers,
> > Magnus
> 
>   I have a prototype class D amp... its good
> for 875KW (short term peak)...  It switches at 1.2KHz
> so its a little noisy but what the heck, its good
> enough
> for rock and roll...
> 
> (actually its a welding control :^)
> 
> Class D seems like an 'acceptable' idea for a laptop
> computer where the sound is going to be lousy anyway
> becaise of the massive 1" speakers...
> 
> In a tiny chip it might be quite workable, but scaled
> up
> to audio amp size, the parasitics are likely to make
> the
> project quite unworkable. I assume that for a project
> to be good for "diy" it should work at least as well
> as a commercial unit (or be made entirely from old
> radios or something else from the salvage bin - in
> that case a little reduction in performance may be
> acceptable for novelty reasons)  :^P
> 
> H^) harry
> 
> 
>