Yes, Timboréale question is interesting and thanks Creative Spiral for confirming that a TRS can also reproduce this LPF Half issue.
This leads to another question. Is this same issue reproducible on the Prophet '08, Poly Evolver, and/or any other models? The former both have "LPF Half" settings and pedal inputs. Since, for posterity's sake, I'm actually really curious if this has affected perceptions of the Curtis chip and PA397 based DSIs, I would love to see this, and thus my hypothesis, tested out.
Can anyone with a Prophet '08 or Evolver series keyboard try this?
1. Set Pedal to LPF Half
2. Insert TR and/or TRS cable and then remove while powered up.
3. Test frequency range of filter.
4. Power cycle unit.--> Is the bandwidth still limited?
Just tested this on Pro 3 and PEK :
Pro 3: Not an issue... if you remove the Exp Pedal with it on, it immediately zeroes out the value. Also, if you leave foot pedal forward and shut down, then remove the Exp Pedal while its off (more likely scenario) - when you power back on it zeroes out the values, when no Exp Pedal is present. So - behaves good. There is one minor peculiarity on Pro3 in that if you have the pedal set to Full LPF or Half LPF, with pedal forward, and then switch to a different Pedal destination in globals, it doesn't immediately zero out the cutoff offsets... though it does upon power cycle always, so not a big deal.
PEK: Works well - removing Exp Pedal while powered on immediately zeroes out the values. Also, if you have pedal forward, power down and remove the pedal, and then power back up without a pedal, it has the values zeroed out as it should.
So, yeah, just seems to be an issue with Rev2... at least out of these three. (it may well exist on P08 too, since the Rev2 OS was probably built off P08 foundation)