Thanks to the recent thread I decided to revisit my non-working
Bi-N-Tic filter. I'd used a BF245A or B for the VCO FET. Not a good
substitute - don't bother trying it. I found a PN4091 in my stash,
soldered it in and the VCO started working right away.
The next problem was the diode that goes to the BC547. I have the
Rev.1.1 board and didn't know about the error on PCB until I happened
to re-read the fine print on the CGS site this morning. Putting the
diode in correctly and fixing a blown trace got the module working...
One modification that I made is that I took four of the 4024 outputs
and summed them into a CGS04 mixer, which I piggy-backed onto the main
board. That output is then fed into the second audio input, adding
some nice "prickly" pulses if I turn up the gain.
It's quite an ornery beast. The patch I came up with this morning made
me think of nails being thrown into a jet engine. I'll try and record
a sample later on.
Bi-N-Tic filter. I'd used a BF245A or B for the VCO FET. Not a good
substitute - don't bother trying it. I found a PN4091 in my stash,
soldered it in and the VCO started working right away.
The next problem was the diode that goes to the BC547. I have the
Rev.1.1 board and didn't know about the error on PCB until I happened
to re-read the fine print on the CGS site this morning. Putting the
diode in correctly and fixing a blown trace got the module working...
One modification that I made is that I took four of the 4024 outputs
and summed them into a CGS04 mixer, which I piggy-backed onto the main
board. That output is then fed into the second audio input, adding
some nice "prickly" pulses if I turn up the gain.
It's quite an ornery beast. The patch I came up with this morning made
me think of nails being thrown into a jet engine. I'll try and record
a sample later on.