Here is an update to my previous post regarding the incompatibility of the POD HD500 with a Mission EP1-L6-RD external expression pedal.

I won't go into all the details of why the Mission EP1-L6 pedal is really not compatible with the POD HD500.  But I did have phone and e-mail correspondance with both Line 6 and Mission Engineering on this matter.

Suffice to say, at the time of this post, apparently Line 6 would need to provide a means to calibrate the external pedal, like can be done with the internal pedal.  And/or perhaps the firmware in the POD HD500 needs to be changed to handle an external pedal that ranges from 0 - 10k ohms rather than 0 - 6.8k ohms.  (This is why only about 70% of the pedal throw is utilized.)  This behavior is exhibited not only when trying to use the pedal to control volume, (as Mission seems to believe) but with any and every parameter you choose to assign to it.

Until something like that occurs, what about us folks that want a quick working solution right now?

It's easy.  Go down to Radio Shack and spend a dollar or two for a 22k ohm resistor (21.25k is what I calculated was required, but 22k works just fine) and connect it spanning the two input jack wires inside the pedal.  Now the pedal will range from 0 - 6.8k ohms making the POD happy!  And if warranty is a concern, then put the resistor (they are very small, and can be installed inside the jack) in a "special" cable you use to connect the pedal to the POD.

And, if Mission or Line 6 ever resolves this issue in the future (which is likely I should think) then just take the resistor out.  Easy!

The entire pedal throw is now utilized, and the transition is smooth from heel to toe, with just a hair more control at the heel end, which when used as a volume pedal gives me more control at the lower volumes.  Perfect!

Additionally, for users of the M9 and M13 Stompbox Modelers, this "modified" pedal still works great.

Admittedly, we should not be having to make any modification to a very expensive pedal to make it compatible with a Line 6 product for which it was designed.  But that's life, and a $1 resistor saves the day.

Have fun!

P.S.  By the way, if you have a Roland EV-5 pedal, you can make the same modification to it to make it work the same.  I know it's plastic and some folks hate that.  But you may already have one, and it is cheaper, smaller, and lighter, and it does work with both my POD HD500, and my M9 Stompbox Modeler.  (As I recall, the Roland EV-5 uses a TRS cable, and I did "snip" the ring wire to make it work with Line 6 products.)