Dual Complex VCO with Video - Audio - Pics

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Dual Complex VCO with Video - Audio - Pics

Post by J3RK »

Please see Page 23 for attached documentation. The files hosted below were removed by the ISP.

Also, there is a ZIP with all of my project docs here:


Old Information / Original Post:

The docs are up, and now updated with wiring diagrams, pics, more notes, updated notes, etc.

New MCVCO Schematic:


Docs Updated 11/11/2013
http://home.comcast.net/~r3cogniz3r/MCV ... -11-13.zip

Lorlin Hex Rotary Datasheet: http://www.lorlin.co.uk/PDF/BCK.pdf

Please post questions in this thread. I'm quite happy to help!

Old First Post:


Thought it was about time to mention what I've been up to for a while (aside from boxed-synth building.)

Since Complex Dual VCOs seem to be the thing to build these days, here's my take:

This will be a three board setup. 2 identical VCO boards, and a control board. The boards are 5"x4" so are Euro friendly on one axis. (this will require a lot of panel space anyway for all of the controls and connections, so these dimensions should be fine in all cases.)

The VCOs I'm calling "Mirror Core". It's our take on the internals of a CD4046 VCO, only built out using separate components. The CD4046 VCO didn't have high linearity for tracking in mind, so we've improved this significantly. I call it Mirror Core because it uses two opposing sawtooth cores (more or less) which is able to generate a perfect 50% square wave.

One of the more unique features is that we expose a logic level unipolar output, which can be used for clocking and logic purposes.

Features of the VCO:

Coarse/Fine tune controls.
1V/Oct input (high tracking range)
Linear FM input
PWM control
PWM CV input
VCO/LFO switch

Saw wave out
Tri wave out
Sqr 50% wave out
PWM wave out
Logic pulse out
Sine wave out

VCA in
VCA out

Lockhart folder in
Lockhart folder out

Control Board Features:

XOR A in + LED
XOR B in + LED
XOR out + LED

Dual Edge Divide by N and Divide by N.5 in
Dual Edge Divide by N and Divide by N.5 out
Dual Edge Divider 16 position rotary
Dual Edge Divider Edge Select switch
Dividided signal LED

LED driver 1 for VCO 1 Logic Pulse Out
LED driver 2 for VCO 2 Logic Pulse Out

Integrator in
Integrator out
Integrator Range control

All features can be brought to the panel however anyone sees fit. I personally will bring them all out as patch points, so I can use each component externally as well.

Between the 2 VCOs and the XOR (or external logic,) complex rhythmic patterns can be made.

The VCAs on the VCO boards are the Mike Sims dual OTA design for low noise/distortion. The wave-folder is a simple Lockhart folder ala Ken Stone's simple folder. Since there is one VCA per VCO, one can be used for an FM index VCA, and the other can be used as a CV input for the folder, (or anything really.)

As you may have noticed, the boards contain everything one needs to do Phase Locking. Just take the logic level signals, patch to the XOR, integrate, divide, and lock the second VCO. You could of course wire this all up, and have a switch that says Lock on it, but I think the XOR and Divide by N are quite useful outside of this function. (so I wouldn't do it that way.)

I've ordered prototypes for the VCO board, and have just finished the layout for the control board. (I'll be ordering protos for that in about a week.) I've been speaking with Clarke about the possibility of a panel for this as well. Once I've tested the full three-board configuration, I will be able to give him more solid IO/control specs after I'm sure everything's good as is.

Anyway, I'm hoping to make these available very soon. I just have one other major project to wrap up for someone first.

All audio demos are now in my Soundcloud page under the 5U set. All of the sounds there are using this VCO.






Last edited by J3RK on Mon Sep 12, 2016 12:15 pm, edited 31 times in total.
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Post by thebot »

WANT! Seriously, that sounds great.
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Post by HueMonContact »

This sounds really awesome. I love the amount of functions you packed into the design. Great job!
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Post by pre55ure »

Sounds awesome, I'd definitely be in for one (assuming it's not ridiculously expensive).

Extra awesomeness if Clarke does a panel as well. :bananaguitar:
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Post by sduck »

I'll definitely order 2 sets!
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Post by Dogue »

Intrigued over here, I says.
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Post by hexinverter »

Looks fun :D

Are there any vactrols? :hyper:
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Post by decaying.sine »

2 board sets for me too.

This smells like a 4U wide MOTM panel with the traditional grid spacing. Not bad for all the features, really.
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Post by djangosfire »

Sounds excellent! I'm in for a few for sure :party:
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Post by nickster »

Marvellous news ! :nana: :banana: :bananaguitar: (all the positive bananas for you sir)

I am very interested in building this project so count me in, please.
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Post by Rod Serling Fan Club »

Nice, what does the "integrator" do?
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Post by tony d »

Awesome ! I think i've found my next project.
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Post by lordofthebored »

Color me :75: this sounds really cool!
thank you thank you thank you
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Re: New Project - Dual Complex VCO "Mirror Core VCO&quo

Post by andrewF »

J3RK wrote:
The VCOs I'm calling "Mirror Core". It's our take on the internals of a CD4046 VCO, only built out using separate components. The CD4046 VCO didn't have high linearity for tracking in mind, so we've improved this significantly. I call it Mirror Core because it uses two opposing sawtooth cores, which is able to generate a perfect 50% square wave.
Great idea! Good luck with the project
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Post by synthcube »

Awesome! Count me in.
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Post by raisinbag »

:75: :help: :75: :yay:
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Post by hexinverter »

Can't wait to see/hear a demo of this one. Nice work sir :goo:
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Post by whitewulfe »

Loving the sound of where this is going!
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Post by blinosynth »

also a rod serling fan club pannel would be great! a buchla-euro pannel (or just a buchla pannel for who would build buchla)...
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Post by Luka »

sounds interesting jerk

looking forward to a demo
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Post by Kalerne »

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Post by theabsent »

My releases: https://laitoshuoltaja.bandcamp.com/releases
My sound art & live gigs: https://www.facebook.com/Laitoshuoltaja/
Modular live gigs (our modular band): https://konekonekone.bandcamp.com/releases
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Post by ringstone »

Sounds very interesting... I'll be on board for at least 2!

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Post by johnnly »

Sounds very interesting.
Looking forward to hearing more.
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