O-scopes are cheap these days, mine was about $225 on Amazon for a two channel. You can visually overlay the channels from a test record through the entire signal chain all the way to the speakers. Easy to spot an imbalance.
Balance control?
I’m running an analog exclusive rig and feel like I’ve been dealing with a channel imbalance for awhile now. I’ve tried trouble shooting this every single way I can think of. The cartridge is set up correctly, checked tubes, etc. My question is: am I obsessing over finding the root cause or should I just cave and use the balance control on my integrated? I feel like it would be ideal to find the cause and not use the balance control. Dose using the balance control introduce anything into the signal? Ugh.