Teletype: conditioning the CV IN for note conversion

My Teletype arrived. Made some progress with some initial scripts, but I’m not seeing what needs to happen to scale a 1V/oct voltage at the CV IN to convert it to a 12-tone note value that I can manipulate and then output using the CV op. There seems to be two ops that from their terse description look like they could be involved- QT and JI. But I’ve not found much in the way of explanation as to how you might use these to quantize the input to a 12 tone scale. The descriptions are pretty vague. Can anyone give me any tips about that and explain how you actually use QT and JI? And if those aren’t the right tools, how you go about converting an input voltage to a note value?

In addition, I created a simple script just to feed the IN to an output CV. This was what I tried first:


I then feed a sequencer into the teletype and listened to the output CV + trigger into an oscillator. Compared with the sequencer hooked direct to the oscillator, the Teletype pass-thru is flat at irregular intervals. Seems that the output is not quite reliably tracking the input. So it occurred to me it could be a trigger timing issue, the input voltage hasn’t settled down when the IN is reading the value. Thinking that might be the case, I tried this:


This seemed to improve it for the most part, but it does seem to mess up periodically, just less often. So I tried 15, 20 and 50 as the delay time, ended up with this seemingly performing a little better, but there still remains some periodic instability, a kind of periodic wobbling of the voltage.

DEL 50: CV.SET 1 IN; TR.P 1

It’s not clear what’s going on-- if it’s jitter in the A/D conversion, or a CV in that hasn’t settled when the value is acquired, or what…

Any thoughts? If I can figure out how to convert to note values first and then use N on the output side, that may help stabilize it I suppose…

This all presumes 12tet:

QT X Y divides X by Y then throws away the remainder. So QT IN V 1 would give you whole volt (octave) increments of your input voltage, or QT IN N 1 would be semitones. Both of these method would output 16-bit “CV equivalent” numbers which you could send directly to an output as V/O CV.

N X is useful when you want to turn quantity X semitones into a V/O CV number for output. E.g. N 24 is equivalent to V 2 is equivalent to about 3276.

Are you running the latest beta firmware? If so, VN X will quantize CV input to semitones and then output number of semitones. It is somewhat equivalent to / X N 1 if you’re on the stable release firmware instead of the beta. This is good when you want to convert to whole number quantities for interval manipulation. You’d input the result into the N OP to turn it back into a V/O CV value.

I’m not familiar with JI, unfortunately, but I do know lots about the more advanced scale quantizing OPs in the beta. They’re all based on 12tet. What’s your desired scale?

I understand how N works, what I’m looking for is the inverse operation, turn CV equivalent numbers into 12t semitones. Sounds like VN X is what I need, as interval manipulation is what I’m trying to do. This is a brand-new Teletype that boots up with v3.2.0 and some cryptic code after that (a build number?). Is the beta generally available? In the meantime, I’ll try / X N 1 to see how that does. Thanks.

Hmm. Tried / X N 1. Seemed to be one semitone flat so I added one, and now I’m seeing the lowest note in the sequence is one semitone sharp…

So, I tried rounding. N 1 on mine is 137, so I used / + 68 X 137. That seems to work at least within the limited range of notes I’m feeding it at the moment (semitones from 12-24). Will run some more tests…

Tests over quite a few more octaves and some fine tuning and I ended up with / + 90 X 135. Looks like maybe that’ll work until the VN op makes it into the release.