On a minimoog model ‘D’ what is the function of the octave range trimmer on the osc board? How is it used in a calibration procedure? I have the older pre-10175 osc board.
-Kris
Hi Kris,
it will scale the change in pitch using the footage selctor switch on the front panel to be a perfect octave. It does interact with the other oscilator trimmers. See the pitch calibration sequence you find in the service manual of the Minimoog. Search the internet for a scon of it.
The model D service manual isn’t accurate. It says to set the VCO range switches to 4’ when calibrating them. Well if your octave trimpot is off then that affects the calibration.
I found this while studying the schematics. The better way is to calibrate the VCOs using range switch set to 2’, not 4’. In that setting the octave trimpot has no effect.
This is the URL for the modified tuning calibration that I posted on AH.
http://www.retrosynth.com/ah/search/lookit.cgi?-v9901.2166
Your pre-10175 board is the “second” board.