Home › Forums › Help/Technical Questions › Can cable length affect the response of an expression pedal? (H.O.G. content)
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July 21, 2010 at 4:43 pm #80520StaccoMember
Can cable length affect the response of an expression pedal? (H.O.G. content)
I mean, it affects voltage, right? not audio, so I wouldn’t think so…. but I made a looong TRS cable connecting my HOG to a Boss FV-550-L and now the expression control goes from zero to full with minimal movement. It seems that all of the action is going on at the beginning of the travel. Say, in octave up mode, it practically jumps straight to the octave as soon as I depress the pedal and then, during the rest of the travel, stays with the same sound.
I know this didn’t happen when I was using a shorter cable, the changes happened way more gradually. (An no, I can’t try and compare with a shorter cable on the fly… cause cheapskate that I am I used the only two TRS jacks that I had to make this longer one). I think I’ll try out with the M-Audio that came with the HOG to see if that still works.
But, I dunno, any ideas? The Boss has no adjustment apart from the minimal vol. Knob (which I know has to be kept at minimum) and the treadle hardness. Maybe the cable is not soldered properly or the ends are crossed? I really have no idea about how these things work!
July 22, 2010 at 1:28 pm #110426CryabetesParticipantthe boss FV50L is a 50K pot right? the proper exp. pedal for these (and the ring thing and boss pedals pretty much everything except yamaha keyboards and moogerfoogers) is 10K. you can build a step-down box (using the parallel resistor formula here ) or just use the M-audio ones
it should be a 12K resistor across the tip and ring of the cable, i think.
July 22, 2010 at 5:00 pm #110436StaccoMemberQuote:the boss FV50L is a 50K pot right? the proper exp. pedal for these (and the ring thing and boss pedals pretty much everything except yamaha keyboards and moogerfoogers) is 10K. you can build a step-down box (using the parallel resistor formula here ) or just use the M-audio onesit should be a 12K resistor across the tip and ring of the cable, i think.
Uh.,uh, it’s the Boss FV-500-L which is actually listed here as one of the pedals EHX recommends for usage with the HOG. I know it HAS worked right with a shorter cable, so the question is, once again, if cable length could be affecting the expression pedal or not. (I did try it today with the M-Audio and it works fine, all across the range of the sweep)
July 23, 2010 at 7:30 pm #110453puretubeMemberHi Gustavo:
the M-Audio exp-pedal has a linear pot (i.e. the rotating variable resistor that is being turned
when you rock the footpedal forth and back)
which means that its resistance and hence the control-voltage (CV) increases linearly from zero to maximum according to the travel (rotation) of the pedal.
This is good most of the time for CV Expression-pedal inputs.The Boss pedal is a volume-pedal which has a logarithmic pot
which means that when it is used for varying the CV, it will vary its resistance (and hence the CV) very very slowly in the beginning of the travel, and then very fast towards the end.
This is good for audio-signal Volume-controlling.Now, depending on how the Tip, Ring, and Sleeve of the TRS-cable are wired,
this can mean that the CV seems to “jump” from min to max or vice versa
either near the toe-down or the heel-down position of the volume-pedal.The resistance-curve of a pot (linear or logarithmic) is called “taper”,
while the logarithmic taper is often also called “audio”.November 1, 2010 at 2:07 pm #112317DimitreeMemberhello
can anyone tell me if the pot on the M AUDIO EXP is a common alpha pot, 16mm perhaps? I’d like to know if the taper is easy to swap with another value, taking it from another pot.
many thanks
Dimitri -
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