If you have an MS-20 and some non-Korg synth (I have a Microbrute for example, but anything else w/ CV out should work), you probably know that it uses Hz/V, and thus won't talk to other synths which use V/Oct. Fewer people know that the MS-20's Total and FREQ IN jacks use V/Oct, and most of those who do have deemed them not really able to track the pitch of a synth.
However, with the CP-251 you can actually get them to work together. Here's how, with the Micro as an example:
- Latch open the MS-20's VCA by plugging a signal into the TRIG IN jack. White or pink noise will work, as will the mod wheel if you have it all the way up (or down, can't remember which). Route its output to the Microbrute, and balance its VCO1 with the Microbrute. Kill VCO2 for now. Set the envelope to an Organ -- full sustain and zero A/D/H/R.
- Turn the Frequency's MG/T.EXT knob to 10, Osc 1 to 8' and hit the bottom C note.
- On the Microbrute, latch the note while you're turning possible (patch Gate In to Gate Out). Set the octave to 0 and hit its bottom C.
- Patch the Microbrute's CV out to channel 3 or 4 of the mixer, and the mixer's +Out to the Total In jack of the 20.
- Set the Master to around 9, then put them in tune with the Offset knob. On my Microbrute they get in tune just below -2 or so.
- Press the high C on the Microbrute, and turn the 251's Master knob until they're in tune again. You'll need a very light touch.
- Repeat the last two steps until it's as in tune as you can get it -- usually takes me 3 or 4 iterations -- and you're good to go.
Once you've got them in tune you can do some fun tricks with the two of them:
- Since the Total jack applies to all three MG/T.Ext knobs, you've now got filter tracking on the MS-20. It doesn't scale nearly as well as the oscillators but I find if you turn those knobs to 8 or 9 it'll track the keyboard alright-ish.
- The glide knob on the Brute only affects the Brute's oscillator, and the Portamento knob on the 20 won't do anything in this configuration. Route the +Out of the mixer through the Lag processor first, retuning if necessary.
- Plugging the 251's LFO into one of the mixer jacks of course gets you vibrato but only on the MS-20 for a neat effect. For more pronounced vibrato mult the LFO, sending one to an attenuator and sending that to the Microbrute's pitch jack, inverted. You can get some damn fine chorusing with this.
- Hitting a key on the MS-20 will add pitch, and hitting D# or E can get you some simple chords. This works especially well on the Microbrute since its subosc can go a fifth down.
- If you'd like the 20 to serve more as an attack transient, route the Brute's Gate Out to the 20's ESP and send its Trig Out to the 20's Trig In. Plugging in directly won't work because of V-Trig vs S-Trig issues. Ah, Korg.
- If you can set your synth to high-note priority, then you've now got yourself some duophony for not much more cash than Korg's Odyssey remake, especially with the Mini now running for $450 Stateside.
