Got this working on Helix floor so thought I'd share what didn't and then did work. Firstly, using TS (Tip - Sleeve - mono - looks like a normal guitar jack) to TS jack lead doesn't work. I've seen one post where people have got this working e.g. with a volume block and setting the min value knob on the EV-30 to max. This did work for me but only seemed to have an an effect after half the the available travel on the EV-30. This was after doing quite a bit of playing with the settings on the helix (global settings | expression pedal polarity). Tried with TRS (Tip-Ring-Sleeve - stereo - has two black bands around it) to TRS lead. Again, this worked after a fashion but would go from min to max (at half travel) and back to min (at full travel). Couldn't get it to work. So, this is what I did, both methods work so if you've got the bits to hand, try it, but neither approach is mega expensive. Leave the min controls on the EV-30 set to minimum (fully anti clockwise):
Get a stereo jack lead (that's a TRS lead)
Put a stereo to mono jack adapter (widely available, very cheap) on one end
Put the stereo end (end without the adapter) in to the EV-30 (works in either output 1 or 2 on the EV-30)
Put the mono end (one with the adapter) into Helix 2 or 3
Assign it to a parameter
Feel the joy!!
Alternative is:
Get an insert (or Y lead) which is 1 TRS (stereo) jack to 2 TS (mono) jack lead
Put the stereo end into the EV-30
Put the mono jack labelled TIP (or SEND) into Helix
You don't need to do anything with the other mono jack
Put the mono end (one with the adapter) into Helix 2 or 3
Assign it to a parameter
Feel the joy!!
You can use both outputs on the EV-30 to get some really creative effects. Plug each output (using either method above) into expression 2 and 3 on Helix.If you invert polarity on output 2 (either on the pedal or in Helix setup but NOT both as it will just cancel out) you can increase the value of one parameter with one expression controller while decreasing the value of another. e.g wah value block and pitch value on a pitch whammy block. Endless permutations.
Enjoy!!
