[sdiy] Synthi A breakout cable

[Magnus Danielson]

From: "m d" <mdimmm at hotmail.com>
Subject: [sdiy] Synthi A breakout cable
Date: Mon, 04 Nov 2002 23:08:04 +0000

> Hello everyone,

Hi!

> I'm looking for some technical advice for a simple DIY conversion.
> I would like to make a breakout cable to connect my Synthi A to my Doepfer 
> A-100 system, and I'm not sure whether to use resistors in the cables or 
> not. Synthi modules connect to each other via 2.7kOhm resistors, and Doepfer 
> modules don't, they're simple patch cables. The breakout cable would connect 
> to the 32-way Prestopatch socket on the Synthi, with the possibility of 16 
> inputs and 16 outputs going into the Doepfer system.
> To keep the signals on suitable level for both machines, should I put 
> resistors in the inputs, outputs, all 32 cables or use none at all?

There is a few things to recall. In the Synthi A you have 0.33V/Oct on the VCOs
and 0.27V/Oct for the filter (if I recall things correctly), which may or may
not be an issue for you. Simple voltage dividers will serve you well for the
scaling.

As for the resistors, they reside in the pins, and there exist different pins
depending on the strength you want. Thus, the feeding of signals into the
inputs is up for a suitable series-resistor. You may want to consider to have
a few CV-mixers for some popular CVs (like frequency controls) so that you can
mix a few signals together prior to tossing them down the line to the Synthi-A.

I would consider buffering, just to keep things properly isolated. The Synthi A
matrix is sensitive as it is.

Cheers,
Magnus