Jurgen's circuit is of interest, yes. However, I have a general rule:

If there's over 10 analog ICs involved, who in the f@*k am I
kidding.

This has saved me from countless failed attempts to recreate
circuits from my past in which I lust and why I stick to the easy
stuff, like Buchla Low pass Gates and simple voltage
processors.

Some day you should all try to have a lookey-see at Buchla's
Frequency Shifter. What a monster. Four different supply
voltages, fhree pages of pure Buchlian-type mumbo-jumbo
schematic diagrams, notes scribbled all over the place.

But....it had no internal oscillator, just two inputs! and...it used the
same IC as it's heart as the Deopfer unit - the 1496.

In any event, the Deopfer Freq Shifter has changed my life -
highly recommended!

--- In Doepfer_a100@y..., "duffnuff" <duffnuff@h...> wrote:
> saw this and thought it might be of interest. home-built freq
> shifter w lo freq capability..
>
> http://home.t-online.de/home/jhaible/hj_fs.html