Aries black boxes (frustration!)

[Grant Richter]

>   The ones I'm referring to are the Linear CV/Exp Current generator and 
>the PD-10 potted module.

The exponential converter seems to be Terry Mikulic's NPN-PNP circuit as
published in Electronotes. See Electronotes #37 page 2. At least I replaced a
block with a 2N3904 and two 2N3906's which worked fine.
The collector of the NPN goes to ground instead of +V.
The resistor to negative supply sets the initial current I believe.
There may be a Q81 type resistor also in the epoxy block?
Anybody with more info?

>   The PD-10 looks suspiciously like a bridge rectifier, but after seeing 
>the size of the black box on the circuit diagram, I can't imagine it 
>being that.

That would be a current controlled ladder phase shifter (10 poles!).
Someone on the list said he had traced it out but he never sent it to me.
Says it's similar to the one used in the ARP Quadra (14 poles).
Tau Systems "The Pipe" also used this design. Still looking for
a schematic!

BTW: My Jan/Feb. 1980 issue of Polyphony has a patch contest and
lists Bob Snowdale as president, Ron Rivera as designer and Mark
Styles and Ken Perrin as user experts. Anyone have any contact info
for any of the above?