Does it happen at all volume levels, or is it only noticeable at very soft levels?? If it only happens at low levels, it could just be the natural effect of the volume control not being able to match precisely...that's natural and it happens with many stereo volume controls. If it happens at all level, then follow the above suggestion and swap tubes side to side. They may not have been a matched pair, one may be older, etc.
Lower gain in left channel.
I just noticed last night that the volume from my left speaker is lower than my right speaker. It is enough that images are pulled towards the right speaker, but it is not glaring. Could this be a sympton of a power tube going bad? I'm running An Air Tight Preamp (with 6 month old new tubes) and a c-j Premiere 11A. I'm not sure the age of any of the tubes of the c-j, I bought it used and have had it for about 1 1/2 years. Would a tube or tubes going bad manifest in this way. There are no strange noises or anything coming from the left channel, just the slightly lowered gain. Thanks for your help.