(Second try to post this message.)
I just finished my dual CGS06 Burst Generator and love it! This project
sat unfinished on my workbench for several weeks, because there was a
strange malfunction I could not understand. Email exchanges with Ken
Stone (very helpful, Ken, thanks) helped rule out possible causes of the
problem. Finally what fixed it was swapping the Fairchild 40106 chip
for a Texas Instruments 40106. Something about all three different
Fairchild chips I tried was off spec. Same manufacturing lot, so it may
not apply to all Fairchilds. Anyway, I bought a bunch of TI chips and
will use them first from now on.
The symptom was: on power-up there would be a continuous stream of
pulses at the rate of the clock. The 4017 counter was not counting.
Most curious, I was able to see very short pulses on the *inputs pins*
of several of the 40106 inverters, and I could prove that nothing
external was generating them. Something seemed wrong internally to the
chip. I became intimately familiar with every pin of the three ICs on
the CGS06 board! I sure know that circuit now. I didn't have any TI
chips on hand at first; I had to order them (from Digikey). And that
was all it took.
I'm glad I used IC sockets; it would have be difficult to fix this
problem without them. I put Mill-Max DIP sockets, Mouser 575-193314,
575-193316, etc., on my CGS boards, except where there is a critical
analog signal path, as on the ASR (the next project).
I added a CGS56 board to each Burst Generator to buffer the 4 outputs to
+/-5V levels. Works great! I have a patch treating the pulses out as
an audio signals into two Synthacon VCFs. Patch the Duration Out to
gate an envelope generator that modifies the VCF frequency, and you get
a great percussive sound.
Two is better than one! You can cross-patch the End Outputs to the
Trigger Inputs of two Burst Generators and they trigger in sequence
quite reliably, giving a two-stage burst. Each stage can have a
different clock rate and number of pulses. This module calls for lots
of experimentation!
-Richard Brewster
I just finished my dual CGS06 Burst Generator and love it! This project
sat unfinished on my workbench for several weeks, because there was a
strange malfunction I could not understand. Email exchanges with Ken
Stone (very helpful, Ken, thanks) helped rule out possible causes of the
problem. Finally what fixed it was swapping the Fairchild 40106 chip
for a Texas Instruments 40106. Something about all three different
Fairchild chips I tried was off spec. Same manufacturing lot, so it may
not apply to all Fairchilds. Anyway, I bought a bunch of TI chips and
will use them first from now on.
The symptom was: on power-up there would be a continuous stream of
pulses at the rate of the clock. The 4017 counter was not counting.
Most curious, I was able to see very short pulses on the *inputs pins*
of several of the 40106 inverters, and I could prove that nothing
external was generating them. Something seemed wrong internally to the
chip. I became intimately familiar with every pin of the three ICs on
the CGS06 board! I sure know that circuit now. I didn't have any TI
chips on hand at first; I had to order them (from Digikey). And that
was all it took.
I'm glad I used IC sockets; it would have be difficult to fix this
problem without them. I put Mill-Max DIP sockets, Mouser 575-193314,
575-193316, etc., on my CGS boards, except where there is a critical
analog signal path, as on the ASR (the next project).
I added a CGS56 board to each Burst Generator to buffer the 4 outputs to
+/-5V levels. Works great! I have a patch treating the pulses out as
an audio signals into two Synthacon VCFs. Patch the Duration Out to
gate an envelope generator that modifies the VCF frequency, and you get
a great percussive sound.
Two is better than one! You can cross-patch the End Outputs to the
Trigger Inputs of two Burst Generators and they trigger in sequence
quite reliably, giving a two-stage burst. Each stage can have a
different clock rate and number of pulses. This module calls for lots
of experimentation!
-Richard Brewster