Fluctuating values on 4pm calibration

Hello all !

I’m in the process of (finally) assembling and calibrating a Shruthi XT with 4pm filter board.
All went along pretty good, I managed to make a few mistake, to fix them and learn from them (also, first chip flashing…) so far so good !
But I having an issue on the 4pm filter calibrating process. When I’m playing the same note over and over again, I’m not getting the same filter oscillation frequency.
They can be quite different, ie when I’m playing C3 with the cutoff at 63, I’m getting values between 500Hz and 4kHz. While this make an fun sample and hold type of sequence, this is not what I’m looking for :slight_smile:

Any obvious thing I might be missing ?

(I believe parameters are good, no waveforms for the osc, no env or lfo modulation for the filter frequency, and I’m getting a proper sine out of the filter.)
I got the styroflex caps from an ebay source, could it be them ? How could I test them ?

Thanks a lot for your help !

> Any obvious thing I might be missing ?

You are probably not starting from the “init” patch, but from a patch in which velocity is mapped to the filter cutoff.

Found it !
I forgot the velocity modulation > filter cutoff…
I swear I looked quite a bit before posting, but apparently you need to bring out in the open your silly mistakes to find the solution right away. :slight_smile:

[EDIT] but you’re too fast to provide answer to padawan like me. It was definitely that. Thanks !

I’m not seeing the init patch though, my first saved preset is junon. did I forgot to flash something ?

[EDIT] Alright, after a couple of unsuccessful tries through the programmer, I managed to get the external eeprom patches transfered via sysex. A couple of them wouldn’t work (#17 and #18) but it seems that most of them made the trip. Thanks

You can reset a patch to default settings by pressing S6 + S1 from the patch load/save page.

Alright, good to know. I guess I need to take some quality time with the manual now that I’ve played with the filter mode and resonance flavours… :slight_smile: (OMG the sound !)

Thanks for your help !