[sdiy] CVs to an old Radioshack Reverb

[Happy Harry]

Hi Kris....

Watch it... knobs are not "just" voltage dividers. They are only
voltage dividers in circuits where you already have voltage control
built in.

Sometimes they are variable resistances... sometimes AC voltage
dividers...

Usually you CANNOT as a rule, insert voltages where potentiometers
were. You need to understand the circuit.

BTW.... Its a BBD circuit so I shouldn't help you NOT BREAK it.. ;^P

But I have mercy on the DIY folk. Nobody likes to break things even
if they do SUCK.

Try and see if Radio Shack can still provide a service manual, etc.

Ask Paul Schreiber of synthtech.com, He a Radio Shack alumni...

If not you need to trace the schematic from the PCB and get data
sheets for the devices. Then we can help you make it VC.

If they are single variable resistors, you could use photoconductive
cells. If they are really pots... it could be harder but is still
possible.

H^)hary


>From: "Rhen, Kris" <krhen at stucki.com>
>To: synth-diy at dropmix.xs4all.nl
>Subject: [sdiy] CVs to an old Radioshack Reverb
>Date: Tue, 16 Oct 2001 13:15:38 -0400
>
>Hi all, found something this weekend.  Used to have an old
>Radioshack/Realistic reverb a looooong looooong time ago and had lost it.
>My parents were having a garage sale this past weekend and we stopped by,
>and what did I find sitting on a table for $1??? My reverb!!!  After
>chastising my father pretty severely :-) brought it home and decided to
>stick it in a module (replace the RCA jacks with minis, get rid of all the
>extra stuff like tape monitoring circuitry etc).  One thing I want to do is
>put CV points around the knobs for dept, delay and mix.  I also want to do
>some similar mods to some of my modules (adding res CVs around the res 
>knobs
>where there are none etc.) so I thought this would be a quick and easy -
>who-cares-if-I-break-it trial.
>
>I realize the knobs are just voltage dividers, so putting a voltage across
>the knob leads should accomplish the same task, with switching jacks to
>break the knob paths?  I'm sure there must be more to it, so any guidance 
>is
>appreciated.  Thanks all
>KRIS
>
>p.s. anyone know what's in this thing?  There's hardly any ICs at all.  Its
>model 42-2108 Stereo Reverb System.
>
>
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