Why my left speaker sounds louder then my right

There's a good chance that the difference you hear is caused by asymmetry in the room acoustics and not the electronics or speakers. In a good setup, a mono source should appear as a phantom image in between the two speakers.

The way to check that is to switch the left speaker to the right and see if the situation reverses. You can narrow things down by switching L/R on the source, then the preamp, then the amp as well as at the speakers.

If room acoustics, you can experiment with speaker placement and room treatment.

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.