[sdiy] CVs to an old Radioshack Reverb

[tpaddock at seanet.com]

I have the schematic for the mono Mighty Radio Shack Reverb 
around here somewhere. 
I don't know how close it is to what you have. It uses a 
MN3207 BBD and MN3102 clock. On it, I think at least one 
slider (delay time?) is a variable resistor that I want to 
replace with a photocell. On mine, I broke the dry signal 
path to make it delay only. (was my first music gear mod)

Harry? I've got 8 more of them. And I'm going cut their 
dry paths. And I'm going to patch them all in a circle! 
All in a circle, Harry, feeding on each other's evil! 
Distortion! Aliasing! Evil! Noise floor through the 
roof! MWAAAAHAAAAHAAA!

http://www.seanet.com/~tpaddock/images/rs_rev_logo_sm.jpg

Thank you,
 - -- -  Toby Paddock

> 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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