Ruby Amp Volume Cut Out? Help

[OddEddie]

I have a little Ruby amp from "runoffgroove" that I built and it sounds great but both the volume (50k) & the gain (5k) pots shut the sound off around 9. Also have a question about the 220uf cap that goes to the speaker as to why it makes no difference which way I orient it, Ive seen schematics designed both ways and built them both ways. Shouldnt an electrolytic capacitor only work correctly in one direction?
Any help is welcome