Vibro Champ Repair Info Needed

[wmharps@xxxxxxxxx]

Hey, Amp Folks (you know who you are):

I have a mid-70s silverface Vibro Champ with the vibro intensity pot missing.  
It works fine without it, but I'm thinking I'd like to replace that pot, which 
was simply snipped out years and years (and years and years) ago.  If I'm 
reading the schematic correctly (and there's a GOOD chance I'm not), it looks 
like there's supposed to be a 25K reverse audio pot there (marked "25K-RA" on 
the schematic: http://www.ampwares.com/ffg/schem/champ_vibro_aa764_schem.gif).

Can someone advise me what is a suitable replacement and where I can get one (I 
need the knob as well, but those don't seem to be so hard to find).  I see that 
Angela Instruments carries 50K RA pots, and 25K (non-RA) pots), are either of 
these suitable replacements.  I am NOT an electronics guy, though I can handle 
soldering the new pot in place, I believe.

Anxiously awaiting good advice,

- -tim