Modular synth madness

This isn't quite enough for a system, so an angled base is put on it containing a sequencer. Two options, (a) just buy Doepfer stuff off the shelf - 

Brother's modular - 

New synth cabinet beginning to take shape. 

So far, this is 6U - two 3U 19" rack mounts. It'll expand (gradually) to 15 or 18U - 5 or six rows. 

At the moment, there are three oscillators, three filters, four envelope generators, a phaser, three LFO's and mixers and splitters galore. The final design will have 9 or 12 oscillators, sequencers and God knows what else in. Lots more soldering to do. 

This will be combined with the other two cabinets (18U) which will form the main sequencer section - with 8 sequencers, 6 oscillators and God knows what else. 

Slightly detuned oscillators, but this is what a Sunday morning around here sounds like. ;-)

Soldering so far, two thirds done. 

Yes, I need more solder. ;-)

Anyway, made a start on the VCOs. Three below. Just some resistors and diodes on at the moment - they cost about a penny each - unless you go for expensive precision resistors, which are ridiculously priced. 

The costliest single components for synth DIY are usually potentiometers (about $1.50 each for decent ones - knobs ($1) and chips, rare ones being quite expensive. ($6 up). One rare chip (CA3046) below, that's a transistor array, the other 4 chips are common TL072 operational amplifiers. One voltage regulator (78L09, +9v) - some 6mm trimmers to tune everything up and a few transistors (NPN / PNP ones) - few capacitors, mainly to smooth the power and to act as buffers for the chips. One 2x5 header strip per board to get the power in as well. 

It's a really simple design, no fancy stuff, all based around early to mid 1970's designs (actually based on the Roland System 100M VCO) - and they sound fabulous. Sometimes less is more with electronics. Should take about 7 hours to build the boards and wire them up - and then calibrate them, which is the fun bit. You just have to be meticulous when building these as they don't tolerate any form of error. 




Edited by Davesax1965 - August 12 2018 at 07:47

PS "Eartha Cat", yes..... ;-)

I think you might !! ;-)

No, well, the total amount of pain is the same for the project, it depends how you spread it. ;-)

I need some special (expensive) chips for the oscillators and some 0.1% precision resistors. One of our cats has been ill, big vets bill (she's OK now) but I think I'll spread the cost of the oscillators until next month !!! 

Quinino wrote: I can't disagree more: one should always, always begin right away with the most difficult work and save the easy parts for last, not the other way around as you seem to have done - now you will suffer extreme pain to conclude the project, needlessly (don't forget to follow my advise next time)

Edited by Mascodagama - August 10 2018 at 11:50