# Best 3340 VCO out there?

**URL:** <https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168>\
**Category:** Uncategorized\
**Created:** [May 2, 2026, 9:38pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168 "2026-05-02T21:38:44Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![tamasgal](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/tamasgal/32/16249_2.png) [@tamasgal](https://lookmumnocomputer.discourse.group/u/tamasgal)\
**Post date:** [May 2, 2026, 9:38pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168/1 "2026-05-02T21:38:44Z")

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Looking for the best 3340-based VCO out there. The less flaws the better 🙂 What’s your pick?

My favourite is [Hero VCO](https://analogoutputblog.wordpress.com/2022/06/20/hero-and-sidekick/) from @analogoutput

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**Author:** ![Kelaifu](https://avatars.discourse-cdn.com/v4/letter/k/46a35a/32.png) [@Kelaifu](https://lookmumnocomputer.discourse.group/u/Kelaifu)\
**Post date:** [May 7, 2026, 12:47pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168/2 "2026-05-07T12:47:05Z")

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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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**Author:** ![DonErskine](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/donerskine/32/26142_2.png) [@DonErskine](https://lookmumnocomputer.discourse.group/u/DonErskine)\
**Post date:** [May 12, 2026, 7:49pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168/3 "2026-05-12T19:49:21Z")

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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.

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**Author:** ![tamasgal](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/tamasgal/32/16249_2.png) [@tamasgal](https://lookmumnocomputer.discourse.group/u/tamasgal)\
**Post date:** [May 12, 2026, 9:01pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168/4 "2026-05-12T21:01:35Z")

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You should probably study the design from @analogoutput He analyses the problem very nicely and designed a beautiful circuit 🙂

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**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\
**Post date:** [May 12, 2026, 9:22pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168/5 "2026-05-12T21:22:19Z")

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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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**Author:** ![Farabide](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@Farabide](https://lookmumnocomputer.discourse.group/u/Farabide)\
**Post date:** [May 12, 2026, 9:53pm UTC](https://lookmumnocomputer.discourse.group/t/best-3340-vco-out-there/8168/6 "2026-05-12T21:53:05Z")

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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?