MFOS "Sub-Commander" Guitar Synth

[dano12]

I'm building it, very excited about this project.

I've ordered the parts, PCB, and already have the enclosure and knobs ready to go:



Started digging in to do some mods--the step sequencer is already done and ready to go. Woot!



Did I mention how excited I am about this build?

[Mark Hammer]

Did we mention how much knob manufacturers are excited about your excitement?

Go get 'em, tiger!

[GREEN FUZ]

Lookin' good.

[GREEN FUZ]

It just occurred to me that you have plenty of room for some extra footswitches to kick a few well chosen parameters in and out.

[slacker]

I think I might have a go at building just the filter, gate/trigger and AD sections, that would make a pretty cool filter stompbox.

[Mark Hammer]

You can also do that with the lower half of this circuit here: http://experimentalistsanonymous.com/diy/Schematics/OOP%20Japanese%20Electronics%20Book/gtr-synth.gif  Note that the HEP6129 is simply a quad op-amp with an LM324/TL074 pinout, so you can probably replace it with a lot of different things.  I know of no direct replacement for the TA7125P, though this link here  http://www2.odn.ne.jp/chietronix/TA7125P.pdf  shows a nifty DIY replacement for it.

The LM2907/MC14046/MC14520/HEP6129 path at the top of the drawing can actually be omitted if one is only interested in the swept filter/VCA part of the circuit and not in the tracking oscillator and octave division.  Just note that since the filter section is a bit like the Steiner filter, in that bandpass vs lowpass is determined by feeding the signal in to different points rather than tapping different outputs (as with a state-variable filter), you will need to provide a path from that FET input stage to the BP/LP switch.  Other than that, it oughta work.

One of the things that tends to be overlooked among the non-analog-modular crowd is the staggering of envelope generators via a gate/trigger delay.  I.E. a gate/trigger delay circuit is definitely worth building in.

[slacker]

The filter part of that circuit has been on my to do list since I experimented with the Steiner filter, never got round to it though. The rest of it's pretty interesting looking as well, although I've read that the VCO part would not work very well.

[StephenGiles]

Did we mention how much knob manufacturers are excited about your excitement?

Go get 'em, tiger!

Andy Roberts, former guitarist with the Hank Wangford Band coined the line - "We sure do appreciate your appreciation!"

[dano12]

Did we mention how much knob manufacturers are excited about your excitement?

I think I've kept knob product managers happy over the last year. 

[widdly]

I'm building it, very excited about this project.

I've ordered the parts, PCB, and already have the enclosure and knobs ready to go:

Hey dano12,

where did you get that case?  It looks really nice.

[dano12]

Hey dano12,

where did you get that case?  It looks really nice.

It is a hammond part, got if from Allied. Check out this catalog page:

http://www.alliedelec.com/catalog/pf.asp?FN=647.pdf

[erix]

Dano - please tell us more about the sequencer you're using.

Is it Tone God's V.P.??

Other?

thx,
erix

[dano12]

Dano - please tell us more about the sequencer you're using.

Is it Tone God's V.P.??

Other?

thx,
erix

I put it together using the info for LED sequencers I found on this page: http://ourworld.compuserve.com/homepages/Bill_Bowden/page5.htm, specifically the 10 LED sequencer. I've replaced the transistors with pots and added a switch that drops RESET so that it can do 2,4,6, or 8 steps. Very simple circuit and fun to play with!

[stobiepole]

Well, my Sub-Commander is up and working...it's everything I dreamed it'd be and quite a bit more...

Very easy build, considering the size, and there's no confusing bits in the instructions and nothing clumsy about the board layout.

Give it a go!

Chris

[Jaicen_solo]

Congratulations, did you etch the board yourself??

Can I be the first to clamour for sound-clips