1 - they don't respond to aftertouch
2 - there is only one modulation buss
3 - they have no noise generator in the audio path
In this post, I’ll address these concerns with a method which will cost you only an audio cable or two. Most people correctly read that a Phatty has only one modulation bus, but we have "additional modulation busses" lying around if we have other synths.
Let me explain. Currently my Slim Phatty is providing me vibrato with aftertouch, but it also does many other things, based on whether I use a slider, ribbon or whatever. First of all, most parameters in a Phatty are already pre-mapped to midi, so if you can buss midi (e.g. with a software midi processor) you can route aftertouch (or any CC you like) to any of several dozen destinations with midi. I do some of this MIDI control, but the particular technique I am outlining in this post relies on the output audio of whatever synth you have controlling a Slim Phatty. Little Phatty users can utilize similar approaches by using the Moog's midi out to control a tone generator (you'll get more mod sources but not aftertouch), or alternatively, using a synth with aftertouch as controller and modulation source.
I am patching an auxiliary audio out from my main (S90ES) rompler synth into the pitch CV of the Phatty. By routing a low frequency sine/tri wave to pitch (volume of wave is assigned to aftertouch inside the rompler, make sure pitch does not track the keyboard, you’ll need to lower the pitch by 3-4 octaves into LFO territory to taste) you have vibrato on aftertouch. (Vibrato is what synthesists most commonly use aftertouch for.) If you send audio rate waves you have as thick an oscillator FM as you might desire. If you use the envelope in the rompler, you can have FM on the attack (for example) and have it decay out beautifully. Or you can crossfade it in when you need it with a slider, or even aftertouch. Most of the tricks we use modular systems for are available on the Slim if we think in terms of control signals. Currently, I have:
a - low frequency sine for vibrato,
b - audio rate signals for FM, and
c - a little white noise going into the Slim's Pitch CV. (The white noise adds a little jitter, to make the Slim's oscillators sound more vintage when that is needed.)
The latter two are activated by sliders and the former by aftertouch. This costs me three out of four tones in my rompler and I still have one more tone available in a single rompler patch.
I can hear someone asking, “Are audio voltages compatible with Pitch CV?” You’ll need to test the output voltages on whatever gear you are using, since you don't want to overload the Pitch CV. I did. The S90ES appears to send about +-1 volt compared to the Phatty CV limit of +-5 volts. This is more than adequate for most musical modulations.
So far, that's just the pitch CV in, being treated to three modulation sources. Similarly, you could use the filter and volume CVs and send a number of mod sources into them. I don’t. To keep things simple in a live situation, I use a footpedal for the filter CV and do most modulation tricks with the pitch CV.
The rompler does all the bussing (it may think it is sending audio, but it is actually sending control signals to the Phatty) for you. The engineers at Moog have designed beautiful instruments. All it takes for us to expand them is a control signal perspective.
Hoping this helps you enjoy your Phatty. Let us know if these ideas are helpful to you and if you use these or similar techniques,
Jerry
PS: Three mod sources is pretty rich for the pitch CV. If you are wondering what can be done with a fourth tone (I did) ... try sending it into the external audio in where it can serve as ...
a) a white noise generator,
b) a brief attack transient or
c) a third oscillator.
White noise from any source functions remarkably well when sent through the Moog ladder.
