I just got my 1995 AC30TBX reissue back from the shop (all new tubes) and at a practice the other night, I put it through its paces to test it out. Everything sounded great except when I switched to the Vibrato channel - the volume seemed to be kind of weak. The Normal and Vibrato channels are normally a little weaker than the Brilliant channel but this seemed a lot weaker than I remembered it ever being before. It also seemed to sound a lot thinner than the Normal channel. With the Brilliant channel at 9:00, I had to set the Normal channel at around 11:00 to be of equal volume (this is normal), but I had to set the Vibrato channel to around 1:00 to be equal to the 9:00 Brilliant volume level (this didn't seem normal).
So I brought it back to my tech guy to check it all out and make sure there weren't any bum tubes, and he couldn't find anything wrong with it. He finally talked to a tech guy at Korg who tested two AC30s in his shop and he ended up with those EXACT same settings for equal volume. So the final word is that this is just the way it's supposed to be - there's nothing wrong with it! I know that the Brilliant channel is the loudest of the three channels, but I could have sworn that the Normal and Vibrato channels were basically the same, volume-wise. Does anyone here have this same "problem" with their AC30?