Quadra Phaser clone is working!
don at till.com
Thu Jun 26 17:54:25 CEST 1997
From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
Date: Thu, 26 Jun 1997 13:49:33 +0100
Started this project long ago, but it didn't work right.
Yesterday I have pulled the circuit out again, found a stupid
little component value error, and suddenly it works:
Very cool! A stereo pair of these in a rack mount unit would be such
a wonderful machine.
Phaser of the ARP Quadra,
14-stage symmetric transistor ladder all pass circuit,
compander system built around a CD4007UBE makes it almost noise free.
I like it very much. I guess it would win the price for the
most efficient phaser design: only 2 transistors and 2 capacitors
for each stage !
How noisy is it without the 4007 circuit?
How noisy would it be without the 4007 but with MAT-02's for the
BTW: It uses some "1N34A" diodes for signal limiting at high
resonance. Didn't find these anywhere. Can anybody
confirm that this would be germanium types ?
Yes, that's the classic germanium diode. Here in the US Radio Shack
still carries them.
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