Connecting Arturia MicroBrute via CV to Mg Realistic Concertmate MG-1

[oredon]

Love the MicroBrute. Anybody know an easy way to connect the MicroBrute to a Mg so it has the correct gate/trigger response (i.e. triggering on keypress, not key release)?

Also, it seems like the CV octave scaling is 1 octave higher for MicroBrute than the Mg. I saw a similar issue in the MiniBrute forum. Any simple solution to this?

[bartleby]

brute (and practically every modern analog synth w/ cv/gate) uses v-trig for gates, the Mg mg1 uses s-trig. so you need a v-trig to s-trig converter. you can build it yourself, it's a very simple circuit. all you need is an npn transistor, a resistor and maybe a diode.

i'd recommend building it right into your mg1, as you will want to trigger it with other modern equipment. that's what i did with mine. but you can also put the converter circuit into an external box, if you prefer that - it's a passive circuit that doesn't need any psu of its own.

here is one description of the circuit, here is another. google will find you some more.

[edit:] btw this circuit is also useful for adding an analog clock input to a digital delay pedal with a tap switch, like the legendary ehx hazarai and many other modern delay pedals.

[bartleby]

as for the +1v offset on the mini and micro's cv outputs - is this really that much of a problem? can't you just use the vco octave switches on the mg1 to get them to play in the same octave as your brute?

[periol]

I have a Microbrute on the way, and one of the reasons I purchased it was to use it (especially the sequencer) with my MG-1.

Despite lots of research though, I have a couple of questions maybe someone can help with...

1.  I'm not great with tinkering with electronics, and the circuit diagrams posted above leave me confused.  Can I just purchase this (or something like it) to make the connection, or is there more to the story?



2.  In order to make this work, I need to connect the Microbrute "Pitch Out" to the "Pitch" input on the MG-1, and then the "Gate Out" to the "Trigger", correct?  Do I need a converter for both? 

3.  The Microbrute has 1/8" jacks, and the MG-1 (and the box in the picture) have 1/4" jacks.  Is there anything to worry about with this difference, or can I just use one of the sleeve converters I already have?

I'm definitely new to this stuff, but excited to figure it out.

[bartleby]

Can I just purchase this (or something like it) to make the connection, or is there more to the story?

i don't know this box, but if it does what it says on the label, you're good.
may i ask what you intend to pay for that little box?
the components you need to build this circuit yourself will be about 20 cents...

[edit:] ah, i just found their website. i guess, 15gbp is an ok-ish price if you don't feel like building your own converter right into your mg1. the most expensive component in that box is the plastic case. you could put some sticky magnetic tape on it to magnetically attach it to the metal case of your mg1...

In order to make this work, I need to connect the Microbrute "Pitch Out" to the "Pitch" input on the MG-1, and then the "Gate Out" to the "Trigger", correct? 

yep. but for the 'gate out' to 'trigger in' connection, you need the v-trig to s-trig converter described above.

Do I need a converter for both? 

no, you don't need a converter for pitch cv. your mg1 uses the same v/oct scale for pitch cv as the brute. afaik, only some vintage korg and yamaha synths like the ms and cs synths used hz/v for pitch cv instead.
but do bear in mind that your brute's pitch cv output has a +1v offset because of the way the pitch wheel is implemented. so playing the lowest note, it won't output 0v, but 1v instead. some people seem to think this is a problem - i can't see why, really.
but if you do think it's a big deal, you could use a cv utility module like doepfer's a138-2 to add a negative offset.

The Microbrute has 1/8" jacks, and the MG-1 (and the box in the picture) have 1/4" jacks.  Is there anything to worry about with this difference, or can I just use one of the sleeve converters I already have?

a simple mono converter like this or this should do the trick. or you could use an adapter cable.

[periol]

Many thanks for the help.

I'm not sure I am capable of making the cable myself, but I'm looking at the diagrams with a friend tomorrow who is more inclined to this stuff than I am, and we'll head to the store and see if we can figure out how to do this.

Thanks again.  I really appreciate it.  Now to make it happen!  Can't wait to use the Brute and it's sequencer with my MG-1...   

[Bruno@arturia]

but do bear in mind that your brute's pitch cv output has a +1v offset because of the way the pitch wheel is implemented. so playing the lowest note, it won't output 0v, but 1v instead.

actually it does output 0V in octave -3.
The issue people are having is that the voltage to frequency mapping is not the same between Brutes and some other synth.
1V for a brute gives C1 = 32.7Hz, I think it's C2 = 65.4Hz for a Mg.

[bartleby]

@bruno: oh, sorry o got that wrong. i was under the impression that brutes only output 0v pitch cv when playing the lowets note + turning the pitch wheel set to +/-1octave all the way down. don't remember where i got that from.

either way, i don't see this as much of a problem, as most other synths's vcos can select between several octaves...