Not a problem. The point of the forum is sharing, also known as teaching and learning. I call it "each one teach one." It succeeds when it's a safe place to be ignorant and ask ignorant questions.
Don't worry, you're not alone.
Thanks for bearing with me!
Another person also supported me in verifying the imbalance. I listened to some mono recordings and it's not possible to disregard it. It sounds like voices and symbals are mixed to the right even though the source is mono (again with the high frequencies).
I also did try to measure the AC voltage on the headphone cable ends, using 150hz. There was no considerable difference. The thing is, I don't hear any difference either when listening to the test tones. It's only apparent when listening to music! It's not the headphone drivers either since the bias swaps when swapping the ends of the cable.
I'm grasping for straws here but I did notice one thing, when bumping my rackety desk,
there is a very noticeable bell-echoing sound produced from the Crack. This sound is only audible in the right channel. Could that be some clue?
I mean, the measurements seem to disprove that there is an imbalance. But I can definitely hear one when listening to music. Do I need a scope to test higher frequencies?
Anyway, Doc B. suggested in my thread that I give it some time for the tube/circuit to break in before I did anything more drastic, as that may change the balance for the better. I'm still super new to this and I know the situation isn't exactly the same but I just thought I'd throw that out there.
Is it possible that the speedball needs to burn in? It has been going for some time now though.
Even though the imbalance is annoying, I've still been thouroughly enjoying the sound post-speedball. I just wish it could be balanced as well!