[sdiy] Phase shifters & Compandor chip availability

[Tim Ressel]

Yo Colin,

Okay, yeah, sure, its the same thing. What I meant
was: is it a case of the ladder having a really low
upper end where compandors are the only way to get
decent range? 

Ah, but wait! I see now that the control voltage for
the compressor is fed to the expanders. This would
suggest a fixed gain through the ladder. Otherwise you
would use a second detector on the expanders. So I
don't think the compandor stage is there to equalize
levels during resonance clipping. It must be for
dynamic range.

Colin, you built the Juergen Haible circuit, which
does not use companding, yes? Is there much noise?

--tr

--- Colin f <colin at colinfraser.com> wrote:
> ----- Original Message -----
> From: "Tim Ressel" <madhun2001 at yahoo.com>
> To: "Synth-Diy" <synth-diy at dropmix.xs4all.nl>
> Sent: Tuesday, January 07, 2003 8:19 AM
> Subject: [sdiy] Phase shifters & Compandor chip
> availability
> 
> 
> > I was interested in the ARP Quadra schematic. Does
> > anyone know why a compandor was included? I figure
> its
> > either for noise reduction or dynamic range
> > enhancement, possibly both.
> 
> Aren't they both the same thing ? ;-)
> 
> > Running the signal thru 28
> > transistors has got to be noisy.
> >
> > Has anyone built one of these beasties?
> 
> I've built two, using Juergen Haible's PCB layout
> from
>
http://www.it.kth.se/~e93_mda/synths/friends/haible/hj_sch.html
> It has a very deep, liquid sound.
> Juergens PCB foil and component layout didn't quite
> match.
> I fixed the component layout, but can't remember if
> Juergen updated the one
> on his page.
> You'll find my fixed version at
> http://www.colinfraser.com/phaser.htm
> 
> Colin f
> 
> 


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