Moog Music Forum

Hello
I just bought a CV-control keyboard Analogue Systems French Connection (Ondes Martenot touch)
and want to use it with a slim phatty (so amazing to play Slim that way)

But there's an issue between the 2 machines : the Slim is not "well-tempered"
when I play an octave (12 half tones)on the FC, it plays only 11 half tones on the Slim

I tried on several other synths (Rolad Aira modular and Sub-37) and it worked.
So I suppose that the Slim CV inputs are not good calibrated.
FC sends 0 to 10v.
I made the 3 calibrations on the Slim (pw, notes, osc 2), I tried the both auto and manual tuning mode
and nothing happened better...

have you any help or suggestions to help me ?

merci

Hello again,
I can put my hands inside the synth but I don't know how I can fix it ...
I have an USB debug-adapter, perhaps it can help too...

michel.bananes.jr@gmail.c wrote: FC sends 0 to 10v.

Hi!
Page 13 of the manual:

Additional CV control:
The PITCH jack on the back panel is a CV input for external control of the oscillator pitch. This input controls the frequencies of both oscillators. A 1-volt change of this voltage will change the pitch by NOMINALLY one octave. The jack accepts -5 to +5 volts, or an expression pedal like the EP-2.

I think there's voltage capability problem.

In that case, it should not work with sub37 too..
cv inputs of the phattys are made to be controlled by expression pedal, more than by keyboards.
I read that it is a well-known problem of the phatty, it works on 0,98 v/oct and FC is giving 1v/oct.
It makes the difference of tune...
I know that there is a way to fix that on Minitaur with sysex,
But I don't think it works for phatty.
This is why I'm asking about an inner trimpot...

The Sub 37s external CV input is calibrated to precisely 1V/Octave - so it works.

The Slim's external CV input is NOT calibrated. Same with the Voyager Old School's ext CV input - it is NOT calibrated but approximates (very roughly) to 1V/Ove.

My Voyager Old School is about 1.27 V/Ove. There is a fix for the Voyager Old School that involves replacing a resistor (R47 100K) with a smaller value resistor (90K) and a trim pot (10K) in series. Why the hell Moog didn't provide this calibration option in the first place is baffling considering the grief it has caused. It would have cost them very little in hardware. I expect the production line calibration and set-up time is the reason.

Anyway, you need to compensate by attenuating or amplifying the CV input until the pitch tracks with whatever external CV source you are using. There's no other workaround.