In response to the "VTV 6550/KT88 Shoot Out
I read a article in VTV Issue #6 (VTV6) titled "KT88&6550 The Power Kings" by Eric Barber. It is a interesting article giving some history about development of these tubes. The above 'shoot out' reminded me of a part of the aricle as follows; "By the 1960's these tubes had set the standard for power amplification. So it was inevitable that other makers would introduce their own versions. GE came out with the straight sided 6550A in 1971. It was called the 6550A, because of the introduction of a exotic 5-ply metal plate material manufactured by Texas Instruments. This metal, produced by cladding a copper and iron core with aluminum outer layers using explosives, made for a more reliable tube with greater bias stability. The clad metal was better a dissipating plate heat, and thus it lessened plate and grid emission and reduced hot spots on the plate.
I am not making a judgement as to which tube is better, but the statement that I posted seems to say that the GE tube had some improvements over the Tung Sol.
I myself am currently using Svetalna's manufactured prior to the selling of the Svetlana name and they sound good. In looking for improvements I may try GE6550A's. One reason for using the GE's is they seem to be a bit more reasonably priced than the Tung Sol's.
Any thoughts.