I started this build back in 2019.
Finally catching up. Sorry for the delay.
I blame a combination of slackness and covid.
Part one is here.
Mouge Mixer/VCA- build notes
The Moog CP3 is a classic so its always interesting to study the circuits.
iT HAS two (inverted) outputs. : a +ve & a -ve
It also has a passive mix bus without the use of op-amps.
The module uses transistors.
And I was unsure what parts to use. The LM394 is obsolete.
What to do? Should I use some cheap Chinese copy off Ebay , ... or maybe a Russian clone ???
I decided to try some matched some BC547s first.
The LM394 consists of a pair of super matched NPN transistors
The Emitter-base voltage is matched to 50 mV
The BC547 is also a NPN transistor
First , you need to match the BC547s.
Here is some info on the subject of matching
Vbe (base-emitter voltage) matching is the most common type of matching done.
I like using a Atlas DCA Pro DCA75
Installing headers
pOTS and jacks next.
Still testing the transistors.
They need to be matched as closely as possible.
The mixer actually has 2 outputs: a +ve and a -Ve.
It's what you'd expect from a CP3 mixer.
However, the -ve is fed directly to the switching pin of the VCA input.
This output is somewhat distorted.
The +ve output is the jack directly below IN2
And YES
It does work with the BC547's
You don't need to buy clones from Ebay.
Links
+ NLC blog
+ official build notes & BOM
+ FB builders
+ NLC blog
+ official build notes & BOM
+ FB builders
+ Wiki
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Click here to return to the NLC Build Index:
http://djjondent.blogspot.com.au/2015/03/non-linear-circuits-ncl-index.html
Click here to return to the NLC Build Index:
http://djjondent.blogspot.com.au/2015/03/non-linear-circuits-ncl-index.html
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