Why my left speaker sounds louder then my right

Is it on all sources?.........or only phono?

If you reverse the speakers, reverse the amp outputs, reverse all the signal leads and cables and nothing changes it is the room. I once sold a high end system to someone who intended to put it into a room with one speaker next to a glass wall. He had other rooms I suggested he use but he wanted that one. Shortly after installation I got a call saying the speakers were diffferent; I went over and reversed the B&W 801s he was using; he could have done this himself as they were on wheels. The sound stayed the same with the other speaker so it was the room.

Make sure all your cables are clean at connection points and connected properly. Make sure your left and right speakers are identical to listening position!!! Make sure if you have tubes that all pins are clean. Please post up if you discover the problem. Good Luck.

Check the (balanced/unbalanced) switch in the back of your amplifier and be sure each channel is set to the same setting.

If you have a switch on a component that inverts the phase independently for each channel, make sure they are the same.