Bug? AX8 manual gives wrong expression pedal wiring

[davidespinosa]

Page 19 of the AX8 manual v1.00.2 says:

"Expression pedals require TRS cables because full control voltage is transmitted to them on one contact (the tip), while less than full voltage is returned to on another (the ring) so the host device is able to sense and utilize the pedal position. The third contact (sleeve) is connected to ground."

But I'm pretty sure the AX8 is "tip to wiper". That is, the AX8 supplies full control voltage on the ring, and the pedal returns less than full voltage on the tip.

 

[glombi]

Could anybody please confirm? I wired my BOS FV500-H like mentioned in the manual. It's working, but I get some nasty noise when using it to control global volume or wah block.

 

[paranoid]

should be no noise using a fv500 connected to an AX-8 pedal port. there is no audio connection there. that pedal should work just fine with a standard trs cable from the expression jack to the AX-8 pedal jack.

 

[PRSfreak4]

It's working, but I get some nasty noise when using it to control global volume or wah block.

Sounds like it's either your preset or some other variable causing the noise. As @paranoid mentioned, it's a contactless interaction between what is happening in your preset and the Expression pedal setting. I would make sure you have a solid TRS connection and that you've calibrated the pedal correctly. Hope that helps, you can post the preset if you want us to diagnose that?

 

[glombi]

The noise was also very present, when i controlled the global input volume via expression pedal. It was even heard more clearly. I contacted g66.eu and they recommend to test the wah with an LFO connected to the wah control. The noise was still there, even with all pedals and unnecessary lines disconnected, so the pedal and the wiring are out of the equation!

I also changed my TRS cable from Wiper => Ring to Wiper => Tip. This didn't help the noise. But both wirings seem to work, weras wah operation seemed more smoothly with the later. I still have to do A/B test to confirm.