Simply amazing.......
This osc chip will fit on an 80?
and you allready have a waveshaper circuit...thats my needs right
there...
wow....I just bought 2 CS60?voice boards to desolder....
I may get the ol'eighty up and out of bed afterall....
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-----Original message-----
From: The Old Crow oldcrow@...
Date: Tue, 17 Mar 2009 22:39:13 -0600
To: yamahacs80@...
Subject: [yamahacs80] VCO153 project in board test phase
Hey folks, its been a while, but I have this thing in testing right
now. This is an equivalent circuit to the IG00153. This differs from
my MOTM-style modular 153 oscillator in that it is strictly the VCO IC
with a ramp output, linear CV input, current bias input (FT) for
octave
select and exponential modulation (vibrato) input. It can use the
original M-board FET and charge pump capacitor, or those can be
removed
and local ones installed. I madethis mainly to see about replacing
things at the chip level, but not relying on custom devices. It is 98%
SMT parts, with only 3 parts left through-hole for the moment (mainly
to
swap things and see how the specs change). It no longer needs an input
offset trimmer, or external frequency compensation of the input
summing
amp. The DIL-16 footprint in the middle of the board is used to
install
it into an actual IG00153 socket. Generally it is low-profile enough
to
fit between M boards (it does in my CS-50). It has internal
temperature
compensation of the charge switch and comparator, making it much more
stable than the original device. The charge pump core circuit runs on
its own internal 10V reference supply.
Eventually I want to craft the entire M-board from standard circuits.
The waveshaper is done (it is the one I made for the 153 module). The
EGs are done. The filters are done. I know how to buildthe VCA, thats
next. In any case here is an image of the board, a bit larger than
actual size. More later...
Crow
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