one speaker louder than the other

Did you swap speaker sides to see if it follows the one speaker or if it is the room?

Hi Newbie,

Yes ..it follows as I switch the IC from right to left..
This proves that my monoblocks are okey? and perhaps it is a preamp issue?
My preamp is also a tubed system.
thanks for any followup.

What is your source component (?) or does it with all sources?

Switch the small tubes, channel to channel, in your pre-amp. See if the volume reduction changes speakers.

If that doesn't make a difference, and especially if you have a critically aligned and triangulated set up, check your listening chair'a position to be sure some one hasn't moved it a few inches (I have to recheck mine every time the housekeepers leave). :-)