Sounds like you do not have a preamp. There are multiple reasons to use a preamp, balance control is on of them.. a good one will improve the sound quality significantly in nearly all systems.
Balance on Tube Amp
Recently purchased Tube Amp and with my hearing left side could use more volume and my living room will not allow me to keep speaker out approx 8 inches out from wall ...
What would be the best Quality way to make this adjustment on Amp with No Adjustment ???