DSE mini-synth rants

[>>>marjan<<<]

Hi all,

I suppose you're all in holiday mood, but when you get back,
take a look at this very interesting project:

articele:   vinyl.plattsburgh.edu/minisynth.html
samples :   http://members.optusnet.com.au/~shudder/minisynth.htm

Right now, I have too many projects started but maybe I'll 
consider this one sooner or later.

Anyway, the schematic has some errors. Here's what I've found:

R41 mic input level pot shouold have lower pin to gnd but
all other components on the same rail should be at V/2 (R2/3
divider) so dot on R41 gnd connection is wrong - others
(I think) are OK at V/2.

C6 at V/2 divider should be C2

IC3 pin 14 should be connected to IC1 pin 8 output (schmitt)
according to text but theres dot connection missing (otherwise
there's no sense to it), but cathode of D4 is connected to IC4
pin 12 which is wrong, I guess it's also dot on the wrong place
(pin 12 should go to IC2,3 input pins 14 and scmitt out.)

R39 is missing from PCB overlay.

Also, if you install separate pll input for IC2, shared R11 pull
down resistor will stay only with IC4 pin 13, so you'll need
another pulldown at pin 12.

I don't like LFO sharing IC with amps and schmitt. I'd consider
making two LFOs in separate 324. LFO wave is square RC filtered
which's strange, I'd use triangle from cap, maybe use remaining
opamps from another 324 for bufferig. Tri/square switch.
Level pot for each LFO (before 4M7 resistors). Range sw for LFOs.
Mix both sections into one output. Maybe simple RM (XOR)?

Now, anybody have idea how to add detune pot to one of the oscs,
just add CV to pin 12 via res or variable res at pin 11?

If you find some more errors, or have some nice mod, please
share...


Cheers,

marjan