Looking for the best 3340-based VCO out there. The less flaws the better 
What’s your pick?
My favourite is Hero VCO from @analogoutput
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anything AO touches is usually the gold standard and this is no exception, I’d have built his if I didnt already have a few (inferior) 3340s already in the rack.
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The AS3340 (and possibly the V3340 and CEM3340) have a well-known problem. Using the Pulse PWM input can cause the pitch to shift. Some VCO designs take the triangle wave instead, and feed the triangle and PW control voltages into a comparator, eliminating the problem by generating the pulse externally from the 3340.
As you would normally have an op-amp buffer on the pulse output anyway, the solution does not need any extra ICs, as you simply configure the op-amp as the comparator instead.
You should probably study the design from @analogoutput He analyses the problem very nicely and designed a beautiful circuit
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You give me too much credit; I merely noted that if I followed Alfa’s recommendation of using a regulated -5 V for the negative power, I found the PWM pitch shift became negligible.
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I have several EWI instruments and my long time favourite is the Akai EWV2000 which is built around the CEM3394 which I find to be a very flexible analogue synth in a box.
The EWV2000 has been on my mod it or pass it list since I got it. Has anyone else used the 3394?
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