My experience calibrating the VCO and 2OSC Sept 24, 2023 20:56:30 GMT
Post by feijai on Sept 24, 2023 20:56:30 GMT
I have recently acquired an old unit with three VCOs and one 2OSC, and have been busy calibrating them. It's not been easy. Some notes:
1. I have a Master IO R2. This unit does not respond to MIDI lower than C-1 or higher than G#3. Don't know about R3 or R4. Note that 0-5V would be C-1 to C3. C3 to G3 is 2/3V extra!
2. The VCOs are good news and bad news. The good news is that the VCOs can be calibrated to track more properly from C0 to A2. Beyond A2 they start getting sharp, to about 25 cents at C3 for example. The bad news is that the VCOs can't do bass AT ALL. On AE's Oscillator Calibration Page it's suggested to callibrate starting at C0, which is supposed to be equal to 1V, and it's clear why: C-1 to C0 is bad. If you calibrate from C0 and up, then C-1 to be over 50 cents (a half semitone) flat! Of course if you can calibrate starting at C-1, everything over C0 will be lost, so that's not going to work.
3. I got all three of my VCOs calibrated more or less identically. But turning the unit off, grabbing dinner, turning it on again and waiting for 30 minutes still had one VCO tracking quite differently from the others. :-(
4. The PWM dial affects the pitch of the VCO even in **sawtooth**: about 10-15 cents. That is not good.
5. The 2OSC calibrate quite poorly as I have heard, but you can use them for bass instead of the VCOs. If you calibrate starting at C-1, you can get about 1.5 octaves before things start going too flat to be usable.
6. 2OSC has 2 CV ins (of course) but only one Bus CV supply (!?!?!). So you can't connect both oscillators to your keyboard without scrounging for another Bus CV on some other module. What?
7. So far I have not seen much voltage loss even with all three VCOs and both 2OSC connected to Bus CV. Maybe I'm doing it wrong? Will do more testing.
I cannot afford new modules, so an OSC2/d is out of the question. But more importantly, I'm surprised that we haven't seen a DCO yet, replacing the VCO (that is, one which has triangle, fine tune, PWM, and ideally sine)