The recommended pedal: Yamaha FC7

The Boss FV-500L is an 8.5k pot. The FC7 is 50k. The polarity may be reversed as well. Last, you need to be sure to use a TRS cable and not TS. Given you can get 3 FC7 pedals to one FV-500L and I read unbiased feedback on non-Yamaha sites about the relative longevity/reliability of the FC7 vs FV-500L - I would think the FC7, as recommended, is really the route to go.

If polarity is reversed with the FV-500L - there are external adapters that can be used to convert the polarity. That's one more thing to go wrong (more pieces, lowered mean time between failure). Still, the potentiometer's properties are going to be different between the two pedals.

To get this worked out, you'd need to switch out the pot.

I wouldn't recommend doing this if you're using the FV-500L for anything that's working in that configuration.

Also, I believe the Yamaha pot is customized to provide some "landing space" at the extremes. Something you may or may not find when procuring a pot to replace. You could get a Yamaha part. Lastly - you're going to possibly be faced with the particulars of the mechanicals and how they provide for (or limit) the sweep of the pot.

There are many factors here involved with modifying the pedal and I wouldn't really recommend going that route. Although some may have the experience and resources to entertain doing that.

Thanks Jason ( @BM haha yep that was expected 😉 ) I found the Studiologic VP pedal works so at this stage I'll save the $100 (for the FC7) and use it instead.

Shame about the FV-500 it is a really nice pedal unit!

When connected to Foot Controller 2 (Super Knob) move your pedal heel to toe, it should move the Super Knob LEDs from minimum at 7 o’clock and maximum at 5 o’clock.
If it does not move them completely, you may not have “saved” any money, at all. The FC7 works at 50K Ohms… I don’t think the pedal you mention operates the same. Does it claim to be compatible with MONTAGE?

When connected to Foot Controller 2 (Super Knob) move your pedal heel to toe, it should move the Super Knob LEDs from minimum at 7 o’clock and maximum at 5 o’clock.
If it does not move them completely, you may not have “saved” any money, at all. The FC7 works at 50K Ohms… I don’t think the pedal you mention operates the same. Does it claim to be compatible with MONTAGE?

Yep as I wrote, works fine 🙂 in both sockets

It claims to be compatible with the Yamaha, really? I was not aware of this, are you certain or just saying that?
Yamaha FC7 pedals are virtually indestructible, if you take of them, I have one I’ve been using since SY77 (circa 1989) — that’s my ‘biased’ feedback.

Highly recommended… get a genuine Yamaha FC7 pedal - support the MONTAGE/MODX community! Get to hear what was designed to happen!