Some days my amp sounds great

Sync

Always worth trying a different power socket.

One circuit in my last house had all sorts of earthing gremlins. When the heating came on my amps would sound awful.

LastMantra

WiresDreamDisasters said:

This is why I own 5 amps

I don't have lots of gear but my settings change pretty much daily. 

Dominic

I find this with my guitars......
When I play them they tend to sound a bit crap
When somebody else plays them they sound beautiful and musical

Gadget

A day? Sometimes 20 minutes makes the difference to me. Walk away, have a break, come back and everything sounds different!

dern

Happens every now and again and for some reason it always takes me longer than it should to realise my wah is cocked.

slowpilgrim

sleep!!