controlling Doepfer DIY synth

[julienvoirin]

Dear Boxers

Does anybody has though to design a basic synth, completly controlled by a custom (or not) application using midibox modules (AOUT_NG, 4066, relay, etc) ?

I was thinking to design a VCO module after testing Seppoman SSM2044 module (it sounds great !) and was looking to ADSR and LFO solutions but i discovered the Doepfer DIY synth :

http://www.doepfer.de/DIY_Synth_e.htm

Edited August 13, 2010 by julienvoirin

[nILS]

Seems like you just discovered modular synths ;) Pick the modules you want, put them on a single PCB, pre-route the signal path if you don't want to bother with cables all the time, control the whole thing from a MIDIbox CV (with some possible code changes) - done :) THat's pretty much what my modular does. For some more interesting and simple modules you might want to check out yusynth.net.

[julienvoirin]

Seems like you just discovered modular synths

yes and no

control the whole thing from a MIDIbox CV (with some possible code changes) - done

ah interesting ! my idea was more to use something like a custom midibox 64 with AOUT_NG moduleS integrated

especially, i am curious about the calibrating of the various CV as i noticed that not all modules were working with CV=0 ; 12V (e.g doepfer ask for (0 ; +5V) on a CV input

my idea is also to ask what need to be "cabled" on this Doepfer Synth and what doesn"t (if i well understood, CV123=CV4 on the VCO )

i am also interested by a modulation matrix in hardware, so what solution : relays ?

everything should be small in order to fit a very small Casiotone i found in a garbage (50cm x 5cm x 10 cm)

the general idea is to have a complete analog solution for the audio and a complete digital solution as control (analog synth midi controlled)

[widdly]

Getting the CV's in the range 0-5 involves using a voltage divider (2 resistors). The problem with the Doepfer is that the ADSR, LFO and the resonance in the filter are not voltage controlled.

If I was doing this, I'd implement the modulation sources inside the Midibox and have the modulation matrix in digital. It would be a lot less electronics and would allow you to do cool stuff like midi sync on the LFO's.

I'd go with 8 CV's out of the AOut NG controlling Osc1_Pitch, Osc1_PWM, Osc2_Pitch, Osc2_PWM, Osc2_Level, Cut, Res and Amplitude.

You could use CMOS analog switches to control other parts. I like the DG series switches ..http://www.intersil.com/products/deviceinfo.asp?pn=DG411 You can use these to switch analogue signals using a DOUT pin.

The different wave shapes of VCO's could be selected with one of these chips. The sync signals could be switched with these. The second VCO signal could be switched to mix with the VCO1 or to frequency modulate either VC01 or the VCF.

You would need two VCO's, two VCA's, and a VCF.

For the VCO's I'd look at the Hearn Morley ones here...http://sites.google.com/site/hearnmorley/synth-diy-resources or the prebuilt pcb's from here..http://mattsonminimodular.com/

Edited August 19, 2010 by widdly

[julienvoirin]

thanks widdly ! exactly the kind of reply i expected