Marco, Mesa Baron Tri Tube mod was 6L6, EL 34, and ?. I was under the impression that it limited to KT types, not 6550's.
I thought the tri tube mod in the Mesa Baron was 6l6's, EL34's and KT88's. I was not aware that it would also take 6550's. I never made the conversion on my Baron (I just stuffed it into a box into my attic where its gathering dust) to the tri-tube - a little birdy at Mesa talked me out of it - so I can't be absolutely sure. I googled this out of curiosity and found no authoritive comments contrary to my belief's.
Could you perhaps have been given a demo of the difference between the KT88 and EL34's? That would be my WAG based on your description of the sound.
I thought the tri tube mod in the Mesa Baron was 6l6's, EL34's and KT88's. I was not aware that it would also take 6550's. I never made the conversion on my Baron (I just stuffed it into a box into my attic where its gathering dust) to the tri-tube - a little birdy at Mesa talked me out of it - so I can't be absolutely sure. I googled this out of curiosity and found no authoritive comments contrary to my belief's.
Could you perhaps have been given a demo of the difference between the KT88 and EL34's? That would be my WAG based on your description of the sound.