# can you use a VCA or Mixer as And/Or gate?

When working with gates. Am I correct to assume that a VCA can be used as an AND gate, and a Mixer can be used as an OR gate? Or am I missing a logical piece of the puzzle?

To me, logic gates implies that they output strong highs (Vmax) and strong lows(0V). The receiving modules have different threshold values for which voltage is considered as high. Using a buffer as described before, a â€śLOWâ€ť signal will be interpreted as LOW and HIGH as HIGH.

And, Iâ€™m not sure that itâ€™s true that VCAâ€™s and Mixers are allways neutral - They might have inbuilt filters (like real world electronics).

Yes thanks. That makes alot of sense. I made the mistake of assuming â€śLowâ€ť is 0V and â€śHighâ€ť is anything above 0V. Even though, theoretically, you can rig up a VCV Fundamental Mixer to work as an AND/OR gate, cant you?

I can make AND by sending A to CH1 and B to CH1 CV. They both have to be 10V to output 10V.

I donâ€™t know how to wire a mixer as an OR gate. If A to channel 1 and B to Channel 2, they get summed. 10+10=20V

BUT, If you see everything over 0V as being TRUE, Itâ€™s a valid OR gate.

Thank you. I know that you are probably thinking â€śwhy not just use one of the hundreds of logic gate modules?â€ť. Itâ€™s just something Iâ€™ve been pondering lately. Except for some filters and reverbs, it will be interesting to see (like a challenge) what canâ€™t be made with the Fundamental Modules. Anyway, thanks for your time.

1 Like

If all your inputs are initially constrained to binary (0V = False, 10V = True), then it is possible to create all possible logic gates using nothing more than combinations of VCV MIX, VCV VCA, and constant CV of 10V (and/or -10V) from VCV 8VERT. All outputs can be constrained to 0V / 10V.

• NOT
• OR
• NOR
• AND
• NAND
• XOR
• XNOR

I posted those constructs at VCV Fundamental Constructs: Logic Gates

In more generic terms, the minimum set of requirements to create all the gates are a collection of

• Summing Mixers
• VCAs
• Inverters
• a single 10V constant CV source

If you have analog inputs, then you can easily convert them to binary using Comparators. Iâ€™ve got VCV Fundamental Comparators as well.

1 Like

Thank you Dave. I have so much respect for you and the input you have given to this community. A while ago I tried what you are doing now with your VCV constructs, but I have up. Your knowledge is inspiring. And your music is awesome.

1 Like

Oh my, Thank You!

I do enjoy discovering ways of creating things with basic building blocks, and sharing what I have learned. And it feels great to get appreciation for both my music and my educational efforts/patches.

But as far as my synth knowledge?.. I have so much more to learn! I donâ€™t even think I know enough yet to realize just how much I donâ€™t know!

3 Likes

well, nobody yet knows how deep this rabbit hole goes, maybe itâ€™s infinite?

2 Likes