Have built a Thomas Henry LM-VCO and in the middle of building an Eddy Bergman / YuSynth ADSR and a VCA. Hooked up to an AI Synthesis Stereo Matrix Mixer and Hexinverter Mutant Brain with an Alesis QX-49 keyboard and SR-18 drum machine.
What should I do with the last 10hp of my case?
a 4hp lfo would be quite a challenge for me, but i’ll look into it. from my understanding, the lfo would let me tweak the vca parameters and it could be used as an fm input for the vco?
If it’s fast enough it’s good for FM, but it can also wiggle that Pulse Width Modulation input. Can also help with lasers/sirens in the v/oct input. Can also wiggle a filter cut off. LFO’s are awesome <3. But if I had to choose in your set up, the filter will make the biggest difference to your overall sound. Your ADSR envelope will do the heavy lifting, especially with that really useful inverted output
Hmm, sounds like it might be worth me adding on another 24hp section to my case so that I can add a LFO. I’ll start with the filter, though - was looking at another Eddy Bergman stripboard layout for a VCF that ought to be quite manageable.
With 24 hp, you could fit a couple of LFOs and have space left for an attenuator. Look up attenuators, I’m sure Bergman’s site has one. It helps a lot for taming your modulations and you can fit like atleast two in four hp. A good LFO module size would be atleast 8 hp with two separate LFOs behind the panel. Some people can cram more in less space but ergonomics suffer. I think it’s plausible with to use a CD40106 (inverting Schmitt trigger oscillator) and a TL074 (output buffer ensuring 0-5v strength) with all the supporting circuits/jacks but definitely don’t take my word for it
That sounds like a plan.
I have some leftover TL074, a few CA3080, a few LM13700, and plenty of TL072 and basic CMOS chips and opamps, but I dont think I have the CD40106, but isnt a Schmitt trigger something that can be built entirely from transistors?
I’m thinking of making a 12hp generative module using arduino, DACs, and some code to operate as many CV controls as I can manage. Would be really cool to have it be able to implement a physical model algorithm for a guitar pluck or something, too.
Oh for sure you can use transistors. Slightly Nasty makes a full fledged VCO from transistors. So a great micro controller would be either the teensy line or even a RP2040 (I think that’s the designation it’s a raspberry pi based microcontroller.). Look up the Europi they have some great code examples you could look at.