Hero VCO module

Here we have the Hero voltage controlled oscillator in Kosmo format. This is my idea of a nice 3340 based VCO, combining features I like from several previous designs. It has fixes for the 3340's most problematic attributes: there's no frequency shift when pulse rate changes and no ringing on the pulse wave falling edges. Amplitudes are a uniform ±5 V for all waveforms — which include sine in addition to triangle, ramp, and pulse. There's a ridiculous but nice 11 position octave switch. But what's that extra pin header for?

00:00 Intro
00:10 Hero VCO
00:55 3340 chip
01:56 Front panel tour
05:21 Under the hood
06:00 Pulse width frequency shift and negative voltage supply
09:24 Pulse wave ringing
10:12 Output amplitudes
12:33 Demo on scope
15:18 Sound demo
17:53 Wrapup and teaser

Music: Ringtone by Rich Holmes

[harrywoodell]

"All" the 3340 fixes in one place! This will be a big help when I build my LMNC oscillators. I've stumbled across most of this on the Discord, but not so well organized and presented. Can't wait to see if this Hero has a Sidekick.

[peternoya]

Awesome project. This VCO is a thoroughbred workhorse. Thanks for sharing your knowledge with us!

[rogrevs]

Nice job Rich. Loving the way that the octave switch goes up to 11. Looking forward to seeing the companion module next weekend.

[EdEditz]

Great job! The octave switch is a great addition. I tried doing that on mine but it was too early on in my DIY journey for me to pull that off successfully.

[mcshafty]

Surely no explanations are necessary for a knob that goes to eleven

The osc sounds great Rictch - I haven't done a build in ages. This could get me out of retirement 😂

Looking forward to vid 2

[VanBroicz]

Very nice! Maybe pair it with a sequential switch so you can cycle through those outputs

[russliquid]

ive never heard zener pronounced ha .... potatoes .... thank you for sharing your knowledge! ive been enjoying the fruits of your labor