Minimoog connection of midi-cv convertor

[roh]

Hi - excuse the newbie questions here; I recently bought my first model D and have found a decent midi-cv box on the web.

Do I need to connect the S trigger input (Cinch Jones plug) or just the osc. and filter 1/4 inch plugs to it?

cheers
R.

[Kevin Lightner]

There are numerous posts in this forum's archives pertaining to this.

Simply put, putting a CV into the OSC input jack will ADD to the keyboard CV.
It will transpose the keyboard and the keyboard will transpose the incoming ext CV.
The CV will not go through the glide, nor be present at the orange keyboard filter tracking switches in the filter section.

The Gate signal will need a 2 prong Cinch-Jones connector and the MIDI converter must be set to "S-Trig" or inverted gates.

There are numerous other problems with this set up.
Since keyboard voltages are only constant when a key is held down, there can be drift which will cause your external CV to also drift (since these voltages added together.)
If one circumvents this issue but taping down a key or putting a pack of matched between keys, all will be well ok in the CV world, but that held-down key will also then be producing a constant gate signal
So that's not such good idea either as your external Gate signal may be ignored.


There are several solutions:

Add a switch.
Have the synth modded in any number of ways.
Use jacks that have shorting switches built into them.
Buy a cable (that I make) that unhooks the Mini's keyboard altogether and instead allows your external signals to replace the keyboard. With this method, you lose your keyboard's usage, but it's simple to put back to stock.
I am also just beginning production of a Minimoog D's keyboard contact board.
It adds MIDI in, MIDI out and provides CV and Gate also.

[roh]

thanks Kevin - simple question, albeit naive perhaps ; )

Do I even need to use the s trig input if I am just using the osc and filter jacks? Or do you need all 3 patched in?

[roh]

oh, as well - can I simply replace the 2 pin cinch jones with a 1/4" female plug?

[museslave]

The weird thing about the Minimoog is that it also includes a weird interface on the front which is activated via kinetic conversion from brain impulses.

[Kevin Lightner]

thanks Kevin - simple question, albeit naive perhaps ; )

Do I even need to use the s trig input if I am just using the osc and filter jacks? Or do you need all 3 patched in?

I can't answer this if I don't what you're trying to do, but I'll take a guess..

How about this for an answer?:

The only two places a Mini gets an S-trig signal is from the keyboard or that 2 pin plug on the top.
Without an S-trig signal, the envelope generators will do nothing and without an envelope generator doing something, the VCA will do nothing and no sound will be produced.
Somehow one must produce an S-trig signal to hear their Mini.

If you just want the Mini to drone for processing external signals, hold down a key or somehow short the pins of that s-trig jack on top.
You can even use a paper clip or metal tweezers inserted, but you might ruin the jack too.

oh, as well - can I simply replace the 2 pin cinch jones with a 1/4" female plug?

The 2 pin cinch jones connector can be replaced with a 1/4" female jack, but it will still need an S-trig signal to work.

"Simply" is the word I have the problem with. The hole for the S-trig jack is larger than most 1/4" jacks, so you'll need washers to hold it in.
With 2 washers and hopefully a lockwasher also, the barrel of the jack may not be long enough to get a nut onto.
There's many alternatives (make an adaptor, use thin washers, use a long shaft 1/4" jack, mount a plate, etc), but it'll still be an S-trig that the Mini wants to see.

Now here's the part that makes things confusing: that jack on top doesn't go to a circuit inside that's used to memorize keyboard notes.
It only triggers the envs generators.

So if you have an external midi to cv converter and hook it's pitch CV to the OSC jack and it's S-trig signal to that S-trig jack (whether 2 prong or 1/4" jack), you will indeed trigger the envs and change the pitch of the VCOs with that midi to cv converter.
BUT... so will the keyboard at the same time.
The big problem here is that the keyboard's voltage is held stable by that memory circuit mentioned above and it only gets updated by the keyboard's trigger signal, not the external s-trig jack.

So what will happen is that when you play your sequencer's midi into the midi converter, it will go to the Mini's osc jack and the pitch will change... but then it will start to droop down in pitch over time.
It will slowly go out of tune.

Now you could place a matchbook between keys or use tape to hold down a key and then the CV would be stable- no more going out of tune.
But that same key held down will produce a trigger too and so your external trigger will no longer be recognized.

This is why a stock Minimoog cannot be used effectively via an external MIDI to cv converter unless the Minimoog is modified in some way.
People see an OSC in jack and an S-trig in jack and reasonably believe they can control a Mini from a MIDI to CV converter, but it's just not true.
What they're not realizing is that the Mini's keyboard is always connected to the oscillators too and it goes through a memory circuit first that will slowly droop in pitch if it doesn't receive a trigger signal from the keyboard.
Besides, the OSC in jack doesn't go through the Mini's glide circuit anyway and not all MIDI to CV converters produce the same style glide (if any at all.)

To properly control a Mini from a MIDI to CV converter, one either needs to build or buy a cable to replace the Mini's keyboard (I make and sell them) or modify the innards of the Minimoog itself. An experienced tech should be employed to perform such a modification.

[roh]

Thanks Kevin - clarity has been achieved. You are the MAN! ; )

cheers
R.

[roh]

The weird thing about the Minimoog is that it also includes a weird interface on the front which is activated via kinetic conversion from brain impulses.

well thats a given...

[roh]

thanks Kevin - simple question, albeit naive perhaps ; )

Do I even need to use the s trig input if I am just using the osc and filter jacks? Or do you need all 3 patched in?

I can't answer this if I don't what you're trying to do, but I'll take a guess..

How about this for an answer?:

The only two places a Mini gets an S-trig signal is from the keyboard or that 2 pin plug on the top.
Without an S-trig signal, the envelope generators will do nothing and without an envelope generator doing something, the VCA will do nothing and no sound will be produced.
Somehow one must produce an S-trig signal to hear their Mini.

If you just want the Mini to drone for processing external signals, hold down a key or somehow short the pins of that s-trig jack on top.
You can even use a paper clip or metal tweezers inserted, but you might ruin the jack too.

oh, as well - can I simply replace the 2 pin cinch jones with a 1/4" female plug?

The 2 pin cinch jones connector can be replaced with a 1/4" female jack, but it will still need an S-trig signal to work.

"Simply" is the word I have the problem with. The hole for the S-trig jack is larger than most 1/4" jacks, so you'll need washers to hold it in.
With 2 washers and hopefully a lockwasher also, the barrel of the jack may not be long enough to get a nut onto.
There's many alternatives (make an adaptor, use thin washers, use a long shaft 1/4" jack, mount a plate, etc), but it'll still be an S-trig that the Mini wants to see.

Now here's the part that makes things confusing: that jack on top doesn't go to a circuit inside that's used to memorize keyboard notes.
It only triggers the envs generators.

So if you have an external midi to cv converter and hook it's pitch CV to the OSC jack and it's S-trig signal to that S-trig jack (whether 2 prong or 1/4" jack), you will indeed trigger the envs and change the pitch of the VCOs with that midi to cv converter.
BUT... so will the keyboard at the same time.
The big problem here is that the keyboard's voltage is held stable by that memory circuit mentioned above and it only gets updated by the keyboard's trigger signal, not the external s-trig jack.

So what will happen is that when you play your sequencer's midi into the midi converter, it will go to the Mini's osc jack and the pitch will change... but then it will start to droop down in pitch over time.
It will slowly go out of tune.

Now you could place a matchbook between keys or use tape to hold down a key and then the CV would be stable- no more going out of tune.
But that same key held down will produce a trigger too and so your external trigger will no longer be recognized.

This is why a stock Minimoog cannot be used effectively via an external MIDI to cv converter unless the Minimoog is modified in some way.
People see an OSC in jack and an S-trig in jack and reasonably believe they can control a Mini from a MIDI to CV converter, but it's just not true.
What they're not realizing is that the Mini's keyboard is always connected to the oscillators too and it goes through a memory circuit first that will slowly droop in pitch if it doesn't receive a trigger signal from the keyboard.
Besides, the OSC in jack doesn't go through the Mini's glide circuit anyway and not all MIDI to CV converters produce the same style glide (if any at all.)

To properly control a Mini from a MIDI to CV converter, one either needs to build or buy a cable to replace the Mini's keyboard (I make and sell them) or modify the innards of the Minimoog itself. An experienced tech should be employed to perform such a modification.

Hi Kevin - do you have these cables in at your store now?

[cameric]

Kenton will make these S-Trig cables for you - they're quite pricey though once you factor in shipping. Very high quality though.

Their Pro Solo Mk 2 is a stellar piece of kit that I use with my mini, rogue, and anything else I happen to have around. The S-trig cable is very simple to use.