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Home Forums Products Stompboxes H9 Aux Switch and Expression help/ideas/setup needed please Reply To: H9 Aux Switch and Expression help/ideas/setup needed please

Alan Cork
nickrose wrote:

Alan Cork wrote:

Hi, I have just tried a Mission Engineering EP-25K expression pedal, which is 25K, but it doesn’t work. I have an Ernie Ball Volume pedal which does work but I want to use that for something else. I bought the Mission pedal because it is 25K. Could be an expensive mistake! I am also using a Boss FS-5U switch. Any ideas why this pedal doesn’t work? It does the 0 -100-0 thing.

We’re not able to recommend the Mission pedal because of this issue. But there is a solution (if you wish to accept it). If you don’t need details, skip the next two paragraphs.

The problem is that the Mission pedal is more of a volume pedal than an expression pedal, meaning that both ends of the potentiometer track are connected to the jack.

If you connect to it with a mono jack (as you must if using it with an AUX switch on an H9, or might with a Factor depending on your cables), this means that both ends of the pot are at ground or 0, while the highest value is in the middle of the track, giving you the 0-100-0 thing you mention.

The solution is to open the pedal and cut the wire leading to the ring terminal of the jack (ask a tech-y friend if necessary). This will fix it at minimal expense. Tape up the end of the cut wire in case you need to reconnect it at a future time.


Thanks so much for such a quick reply. I still have the chance to send the pedal back so that’s what I’ll do.

I thought that all 25k pedals would be ok and it’s a bit frustrating (to say the least) that this issue hadn’t been highlighted before. Anyway, I’ll go for one of the recommended pedals, if I can find one.