Swapping tubes,then cables is a start.Oftentimes it's sound waves building up on one side/ corner of the room. My room for instance has bass build up in two corners diagonal to each other. Behind the right speaker and behind me to my left. I solved my problem with room treatment and a *swarm* of subs.Not saying that's the case, but just something to check out.
Tube amp bias adjustment advice
I biased my first set of tubes on my 211 amp recently and am hearing more volume from the left channel. Does that mean I need to turn up the bias on the left channel to center the soundstage? Thank you in advance.