EXPRESSION PEDALS

leoder

New Member
Hi Ron, first post here as a newby... I see from earlier in this thread that it's possible to switch the polarity on the Mission Engineering EP1 exp. pedal to function correctly with the GT & PBC - I have a MMLT/7 so assume it's the same ? Would this be possible though with the LT and the SP2 Exp. Pedal to function both as a switch and exp. and/or other possibilities ie. with the SP2/two channels ? And if so, would both outputs require the polarity reversal - or rather, what would be required if it is feasible ? I hope that makes sense ! Many thanks, Alan
 
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rjmmusic

Administrator
Staff member
Yes, the LT would work the same way once you've reversed the polarity.

An SP2 would work ans an expression pedal, but not a switch, the switch is used for a different purpose on that pedal. You could use the second output of the pedal to connect to a different device in addition to the LT, but it won't have any additional capabilities on the LT compared to an SP1.
 

Dbow

Member
The problem is that Boss kinda tricked us with that one. Their reverse switch doesn't reverse tip and ring, it reverses the 2nd output so that when one output goes up in value, the other one goes down.

Reversing tip and ring, via cable or modifying the pedal, will fix the polarity issue.
So I did the reverse cable solder and the Boss pedals are better but I'm still getting nearly all my signal from the top half of the pedal. They don't really do anything through the first half of throw. Any suggestions to fix this?

Thanks!
 

rjmmusic

Administrator
Staff member
So I did the reverse cable solder and the Boss pedals are better but I'm still getting nearly all my signal from the top half of the pedal. They don't really do anything through the first half of throw. Any suggestions to fix this?

Thanks!

The cable should fix it., if it's wired correctly. Did you try calibrating the pedal? And, have you tried another expression pedal input on the GT?
 

Dbow

Member
The cable should fix it., if it's wired correctly. Did you try calibrating the pedal? And, have you tried another expression pedal input on the GT?
I have other pedals that seem to work fine. I soldered the cables correctly to swap tip/ring and checked them carefully. Are there any settings on the GT to help compensate for this? I really, really wish I had installed these pedals before the return date.
 

rjmmusic

Administrator
Staff member
I have other pedals that seem to work fine. I soldered the cables correctly to swap tip/ring and checked them carefully. Are there any settings on the GT to help compensate for this? I really, really wish I had installed these pedals before the return date.
There isn't any setting that could compensate for a reverse polarity pedal. However, if it was calibrated when it was inverted, then you definitely need to calibrate again once it's not inverted.

You're sure that you have the tip on one side connected to the ring on the other, and ring on one side connected to tip on the other? It's pretty much a physical impossibility that it would work the same way with both straight TRS and swapped cables.
 

jasonmauer

Member
Ah, thanks for finding that! The lag is because it''s sending (or trying to send) twice as many CC messages. If device is set to None, it shouldn't try to send to that device. I'll look into the issue.
Following up to this issue I reported earlier -- it turns out the problem I was experiencing was most likely due to an intermediate MIDI box I had in the chain that was dropping MIDI messages (probably from overloading the bus). When I switched the box out the problem went away entirely.

Could have been a combination of factors; I'm not 100% sure I traced down all the root causes, or if there was more than one cause -- but at least things are working as expected again. Thanks again for the continued support.
 
Hello,
I own a Boss FV500L (used without ever having a problem with the Liquid Foot Pro pedalboard) which I use to control the volume of the Kemper and an identical pedal to control the Whammy4.
Once I connected my Boss FV500L to the pedalboard via trs it should have communicated correctly with the Kemper and instead it oscillated and was unusable (connected directly to kemper it worked wonderfully), checking the characteristics of the compatible pedals for RJM I was shown that for this type of expression pedal I had to invert tip and ring, which I did but without success, it continues to oscillate on kemper, also calibrated on kemper and GT but it remains unusable connected to the pedal board.

As for the Whammy, no problem, it was enough for me to invert the tip and ring and it works wonders (I clarify the messages do not go through kemper but through a midi switcher)

What do you think could be the problem? Could there be a conflict between the two systems? I specify that I have already thought about the solution of changing the pedal or removing the volume and I don't like it very much

Thanks in advance, cheers
 

rjmmusic

Administrator
Staff member
Oscillating? That doesn't sound like an expression pedal problem... Check your MIDI settings on the GT. MIDI Merge should be turned off and MIDI Receive Channel should be should be set to None, or at least set to a different channel than the Kemper is. Either one of those settings will cause a MIDI loop.
 
Sorry but I can’t find Merge, can you tell me where is it? Anyway I show you my settings

for oscillating I mean this (sorry but I no able to upload a video here) https://we.tl/t-IiQ1rDSrjn
 

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rjmmusic

Administrator
Staff member
Merge is in the Globals tab, in the lower right corner of the MIDI section. It says "Merge: In Out Thru"

I don't know what would cause that problem, especially since it works fine with the Whammy. Your settings on the GT look correct.

Does it stop oscillating if you unplug the cable from the MIDI input on the GT?
 
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