korg ms-04 lfo pedal

[snufkin]

the korg ms-04 is a foot pedal that provides an useful set of waveforms (TRI,SQUARE, RANDOM, GLISSANDO ) and has dual outputs

it runs off of two 9v batteries (bipolar I presume)

heres the manual
http://www.korganalogue.net/korgms/manuals/pp/0401.html#ff

any way got me to thinking (inspired by that modular effects beast Mark Hammer posted I think ?) it could be used as an awesome master modulation controller for a modular effects setup as long as;

1) there are no unobtainable parts
2)its complexity to features ratio is acceptable

i would propose building it as part of the system with an external expression pedal

so anyone have a schematic ? 

good/bad idea?

[frequencycentral]

I've got MS-50 and MS-02 schematics - but no MS-04.

I used to have the whole system: MS-10, MS-20, MS-50, SQ-10, MS-02. It just couldn't compete with my Roland 100m, ARP Odyssesy, my DIY modular or my DIY EMS Synthia.

[snufkin]

I used to have the whole system: MS-10, MS-20, MS-50, SQ-10, MS-02

no VC-10 then, what was the point?  ...

diy ems nice!

I want the ems speech synth where you draw the wave forms with a ball point pen    or at least for someone to explain to me very slowly how it worked
http://www.ems-synthi.demon.co.uk/synthis.gif

but currently I'm building an SNvoice based mini modular

[frequencycentral]

I used to have the whole system: MS-10, MS-20, MS-50, SQ-10, MS-02

no VC-10 then, what was the point?  ...

Yeah, I knew I was missing something!

diy ems nice!

Yes very nice. My brother built that for me. Its got all the improvements, including hard and soft sync, stable oscillators, gate input and 1 volt/octave CV input. The only thing its missing is the reverb, he built in sample and hold instead so no great loss. I felt so in his debt that I built him Thomas Henry's Superseque - 16 step ananlogue sequencer with 2 rows and forward/reverse/alternate ability. I even designed a nice little controller for it so you could use a clock divider to define how long it ran for. Best damn sequencer I ever built! I just gave him a Valvecaster too - so he's been payed back!!

but currently I'm building an SNvoice based mini modular

What's that?

#

Did you see the 12 volt tube VCF thread?

http://www.diystompboxes.com/smfforum/index.php?topic=69713.0

I'm going to build one into a pedal and another into my modular.

[Paul Perry (Frostwave)]

I have a rough copy of the MS04 schematic. (not really possible to build from, without a lot of guessing and tears).
I have a MS04 & it is very frustrating: the reason is, that while you have a pedal, there is only ONE pedal - and you really wish to control more than one variable!
(yes, you can control more than one at a time, but they have to vary locked together).
You feel as though you are playing an analog synthesiser, but it has only ONE knob, and that is controlled by your feet!

Verdict: a great unit, but held back by the limits of human anatomy.

[snufkin]

What's that?

http://mypeoplepc.com/members/scottnoanh/birthofasynth/id22.html good old Thomas Henry 

its a small almost complete synth in a very tiny package based on the SN76477 sound fx generator

its taken a back seat to my ADA tho

Verdict: a great unit, but held back by the limits of human anatomy.

thanks paul good to hear some reports on what its actually like

[frequencycentral]

Isnt the 76477 square wave output only?

[DougH]

I have a rough copy of the MS04 schematic. (not really possible to build from, without a lot of guessing and tears).
I have a MS04 & it is very frustrating: the reason is, that while you have a pedal, there is only ONE pedal - and you really wish to control more than one variable!
(yes, you can control more than one at a time, but they have to vary locked together).
You feel as though you are playing an analog synthesiser, but it has only ONE knob, and that is controlled by your feet!

Verdict: a great unit, but held back by the limits of human anatomy.

In the synth world I hear what you are saying. But in guitar world, I wonder if there is any value in this type of thing for controlling modulation effects like phasers or flangers? It may be a case of driving a thumbtack with a sledgehammer, as I don't think you need the LFO built into the pedal for this kind of thing. But it's still an interesting idea.

[Dan N]

I took a shot at cleaning up the schematic and got this:

http://users.rio.com/senorris/junk/MS04schematic.gif

Don't know the value of the zenor or that one resistor on the base of that transistor.

I even made a pcb (with just the 4X option):

http://users.rio.com/senorris/junk/ms04/

Populated it and threw it in my box of crap I'll probably never get around to wiring up.

[Paul Perry (Frostwave)]

thanks Dan, saved my eyes!
The MS04 is actually a very handy thing if you need a flexible voltage modulation source - for example if one had a Frostwave Resonator or Blue Ringer 
It would be more flexible if one half of the dual 10K pot was replaced by a second pedal, say an EV-5.

[snufkin]

The MS04 is actually a very handy thing if you need a flexible voltage modulation source - for example if one had a Frostwave Resonator or Blue Ringer 
It would be more flexible if one half of the dual 10K pot was replaced by a second pedal, say an EV-5.

exactly Paul i have allot of pedals/synths that could benefit from this

I'm in the process of debugging an old korg x911 guitar synth I got for cheep (I have it mostly up and running) actually tracks very well!
and it has allot of modulation inputs fm,vco and so on the ms-04 would make it a fully fledged mono synth as it lacks an LFO of its own
it has the ms-20 filter in it 

I also have an almost complete ada flanger

Insert Quote
I took a shot at cleaning up the schematic and got this:

http://users.rio.com/senorris/junk/MS04schematic.gif

Don't know the value of the zenor or that one resistor on the base of that transistor.

I even made a pcb (with just the 4X option):

http://users.rio.com/senorris/junk/ms04/

Populated it and threw it in my box of crap I'll probably never get around to wiring up.

awesome work Dan thanks for sharing I may etch this and try it at some point   

Posted by: frequencycentral

Isnt the 76477 square wave output only?

the sn voice does noise and tri as well !

[frequencycentral]

Posted by: frequencycentral

Isnt the 76477 square wave output only?

the sn voice does noise and tri as well !

A synth without sawtooths (teeth?) is like coffee without danish - something missing!

[Mark Hammer]

I'm in the process of debugging an old korg x911 guitar synth I got for cheep (I have it mostly up and running) actually tracks very well!
and it has allot of modulation inputs fm,vco and so on the ms-04 would make it a fully fledged mono synth as it lacks an LFO of its own
it has the ms-20 filter in it 

There was a variable filter resonance mod for the X-911 that appeared in Polyphony around 1981 or so.  I installed it on a guys  X911 somewhere around 1983-84 and it worked out really well.  Drop me a PM and I'll see if I can find the info.  It essentially involved (as do so many of these) replacing a single fixed resistor with a fixed+variable solution.