Ok to adjust balance to achieve center vocal image?


I have an all analog tube vinyl system and don’t remember having to adjust my balance setting in order to achieve a center vocal image. I do now though. I’m getting a left leaning vocal image with the balance set to zero. Is there a good way to see if this can be fixed so I don’t need to balance adjust to achieve a center vocal image? Could it be a preamp tube going out? Something else? Any harm in just continuing to adjust the balance - meaning am I experiencing any signal loss doing so? 
Thanks! Paul
paulgardner
The OP states that he has a "left leaning" vocal image.  Is everything leaning left or just the vocals?  My experience is that many recordings have the vocal image where it should be in space which is not necessarily dead center.

Second question is: When did this change or when did you become aware of it? 

Regards,
barts  
@barts I would say it’s not necessarily just the vocals that are left leaning but the vocals are the most noticeable meaning the loudest element. 

I first noticed it a month ago or so but nothing has changed in the system for 6 months or more. 
Thx
Post removed