JJ KT77 Tubes Vs Tung Sol 6550s

They're in my EL34-based amp. Compared to various EL34's theyre more linear, and pretty dynamic as well (strong bass, good treble extension). A much more modern-sounding tube than the romantic Mullards, not as brite as the EH, more rounded than the SED's.

As far as 6550's go, I haven't heard the Tung-Sols (either old or new). My KT88 amp is a Citation II, much modded, and in that amp I strongly prefer the KT88SC solid plate tubes over the EH KT88's, over the GE 6550's, over the SED flying-C 6550's. A really nice sounding tube available from Penta Labs, or a bit cheaper from Dougs Tubes. That's my recommended tube for amps that support it.

The bias points are different for the KT77's vs. the 6550/KT88's. the KT77's require lower bias, so shouldn't be a problem if your amp supports.

Hope this helps!

Re the JJ KT77s, these are excellent-sounding tubes, better than some of the Mullard EL34s I have, but not quite as musical as my best ones. Certtainly a bargain at the price, although I understand that their quality control isn't stellar (my pair is fine). Dave

Dave,
What tubes that you have sound better?

Eagleman, my best sounding pair comprises two old Mullards, one an Xf1 code and the other an Xf2. The KT77s hold up well in comparison, though, especially considering the price difference ($36/pr. vs. approximately $225). Dave