Both good suggestions. I was looking to do the same, but opposite. The Vox Pathfinder has nice sounding reverb but full on it sounds like 3 on other amps. I wanted to get more but eventually I said whatever its fine.
I don't think changing the taper from a to b (audio and logarithmic) will help. You'll want to either double or the half the stock pot probably as a starting point.
Make sure you know how discharge the caps before you go poking around, they retain charge even when the amp is off and unplugged and can be fatal if shorted.
WTB a Vox DA5 Amp. PM