Doepfer

Peter

> if you can get to the scanner, let me see the schemo, if you can.  
> Dieter needs not worry - for $170 for the completed module, 
> there would be little reason to attempt to replicate it from scratch 
> - that would end up costing someone a lot more $$!.

	Had a quick look at my 'scribblings' on the 126 last night -
unfortunately I have only drawn out a small part of it neatly, but if
I get time over the weekend I'll draw some more out tidily (and then
see if I can sweet-talk our secretary to let me use her scanner in
works time...). The quad osc uses the 2 VCAs in a CEM PA382 chip
(exponential response). The circuitry summing the shift CV which is
then applied to the 382 includes an 'offset' preset, and this should
thus be setting the lowest frequency of the oscillator. From my rough
calcs, assuming the gain of the VCAs is 1, the oscillator would run at
approx  15kHz: estimating the gain at the actual voltage applied for
max and min shift gave me frequencies of 6.5kHz and 30Hz, which tied
in well with the measured values on my 126 of 5.8kHz and 57Hz. Thus
reducing the lowest shift possible may be simply a matter of twiddling
this preset a bit (although the osc is AC coupled to the 1496 chips of
course...). This also suggests that it would be nice to see the
service manual for the 126 anyway, to establish just what Doepfer's
set-up procedure with respect to this preset is (and of course this
will include the schematic anyway...) - it's a real shame that its
priced just a bit above what I'm prepared to pay, just for the sake of
having it, but I could be even more tempted if Doepfer made it
available on a CD, 'cos then at least one could use babelfish  to get
around the language problem!

Tim

[The views expressed above are entirely those of the writer and do not
represent the views, policy or understanding of any other person or
official body.]