Tube amp bias adjustment advice

How about using your cell phone, buy a SPL plug in mic. Calibrate the mic and do a test or two. Quit guessing and see if one is actually louder than the other.

https://www.amazon.com/Dayton-Audio-iMM-6-Calibrated-Measurement/dp/B00ADR2B84/ref=sr_1_2?crid=3KHWP

ES posted this little mic and it works quite well. 19-20.00 usd

Order now and Prime usually gets it there in a day.
How are those ears? Make sure.

Most important, make sure you don’t have a speaker wired out of phase or something simple like that. A wire that is mismarked, or hooked up wrong.. Being that far off center is more than a balance issue.
Balance is time arrival, somehow that’s being messed with, right?
Phase shift, will cause a lower spl and late arrival..

Check for proper connection on the monitor section to the bass section.
Make sure they are in phase.
Check the SPL, make sure.. 20.00 one day...

Regards

My speakers are 20 inches and 23 inches from the back of the speaker to the back wall but if you measure from the front of the speakers to the sitting position they are both exactly 84 inches. Measuring from the back of the speaker to the back wall is a good starting point but if you want to be exact you must measure from the front of the speaker to the sitting position I’ve been doing this for over 50 years and I have yet to have the same measurements from the back of the wall to the back of the speaker there’s always some adjustments needed I hope this clarifies my position. Warmest regards

I had a chance to try a few things including different sources and swapping the speaker cables. I must have hearing loss out of my right ear because I noticed no difference. I will buy an SPL and verify but I asked my GF and she said it sounds balanced when seated in the middle.

One more thought, it could still be my room so I will explore that after I do the SPL.

@needfreestuff i hear what you are saying but my room is a large rectangle 25x20 feet. That being said, the spacing from the back wall is more important in my situation. There is 10 feet between the speakers and only 10 inches between my ears. BTW the speakers are 30” from the back wall on the inside and 32” on the outside.
Bigger issue I believe is a large skylight above the left and not one above the right speaker. If I could post a picture it would be much easier but I don’t see an option in Audiogon

@mmporsche 

you can get your hearing tested too... if you really are wondering

good luck