No preamp 'Balance' control?

Before long, you will be asking for a 'loudness' control. Remember those? I am often amazed that the hi-end thinks convience controls takes away from the 'purity' of the sound. How silly. I have a tube pre-amp with separate channel controls. I seldom use that feature, in that I have a remote that has a balance control.

In my experience a Balance control is most useful in troubleshooting. Never necessary with prerecorded music.

I'll never buy a preamp without a balance control. I think it's mandatory on a tube preamp as the tubes will age slightly different and a balance control helps keep things in line.

Most but not in all recordings the singer or main instrument is in the center. If you have a mono switch in your preamp set it to mono, if everything is in the center switch back to stereo and if the singer or instrument is not center that’s way the record was recorded. If everything is not in the center with mono then you definitely have a problem. I have more than a few albums that seem out of balance but that is normal again because they were recorded that way. BTW this seems to be more evident the better the system gets, probably because there is better channel separation especially with vinyl.
Ther are a few threads on this subject here on audiogon.

Balance controls are really tricky to implement, but valuable if done right. Tricky as they can cause degradation of the sound the way a volume control can (loss of detail and bandwidth are the 2 big issues).

OTOH if you don't have one, recordings that are poorly mastered or any weird imbalances in your system including room anomalies will not image right. Generally you only need a few db, but IME those that have really highly resolved systems may only need 1/4 of a db of adjustment, while those with poorly set up systems might need considerably more. So the balance control has to be continuously variable and have a little range, yet somehow not affect the sound.

Our solution was to create a control that varies the *gain* of the circuit rather than the level of the signal going to it. This keeps the control out of the signal path. It also limits the range of the control to about 8db, but allows for the micro adjustments that can really make the difference.