Tim's Ancient Analog Synthesizer Page
This is my Monophonic Synthesizer. It was
designed
and built in the late 1970s.
It is shown here with all the patch cords
removed
so the panels are more visible.
Some of the modules were never completed beyond
the panel.
Click any image for a bigger version.
I apologise for the quality of some of the
schematics.
They were done before PCs
and schematic drawing software was available.
Also, many of these designs are
obsolete now. There are many good synth
schematics
available on the web.
I've got a lot of other old schematics which I
may add to this collection if there is any
interest. I read and recommend the SYNTH-DIY
mailing list. Due to spam, I
can't provide a mailto: link, but if you want
to contact me, use tim (at) chromaticsound (dot) com.
VCO
Unfortunately, I seem to have lost the schematics
for the VCO modules.
However, there are a number of good designs
available
on the web that I would
consider if I was starting today. See ASM-1
homepage for example.
VCF - 2 pole state variable
This is one of the better documented modules.
Both the schematic and PCB diagram
are on this page. Also, I have scanned a research
paper I did on the design, which contains
the schematic as well as a number of design
equations
and derivations. It is in Acrobat format:
Voltage
Controller Filter Research Paper
VCA
This circuit uses the rather obsure technique
of
parallelling the CA3080 inputs with a biased
diode
bridge to compensate for the non-linear response
of the OTA. Thus the input levels could be
increased,
and a better signal to noise ratio was achieved.
Much better VCA chips are available today.
ADSR Envelope Generator
Sample and Hold
Ring Modulator
The MC1595 is a true 4-quadrant multiplier.
LFO (8038 based)
I added an extra output stage to turn the
symetrical
triangle output into a true rising or falling
sawtooth.
Pseudo Random Noise Generator
This circuit is incorporated into the same module
as the LFO. It generates white and pink noise,
as
well as filtered random low frequency control
voltages.
Flanger
This is a typical design using the now scarce
SAD-1024.
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