I'm near the end of my SFDR recap job. I've found an existing cap on V3 that seems to be installed backwards. It looks non-original (the only one like that in the amp). It's a 35uf/25v with the + end on the ground eyelet (near the front controls) and the - on the eyelet that goes to the tube socket. The schematic I have says that's wrong but the amp has always worked fine. V2 is the reverb pre but I've never had a problem with reverb. If the cap is wrong, why do things work ok?