no problem. For best performance you'll want to ensure the quad is a matched set, meaning they share a like output rating. Since the GT is cathode biased the tube rating and make are a personal preference and no bias adjustments are required. I've heard only good things about TAD 6l6 and 6v6s.
The real art of conversation is not only to say the right thing in the right place, but... to leave unsaid the wrong thing at the tempting moment. - Dorothy Nevill
Post by Phil (aka Phil) on Jul 23, 2009 7:04:17 GMT -7
My GT seems to be finicky about power tubes. The GT is an ultra high performance machine; it's like an F16 fighter that's inherently aerodynamically unstable It's really pushing those power tubes hard. I blew an EL84 once (no bad jokes about happy EL84's here please! ) and just put in the quad from my MAZ Sr. It hummed like crazy. I put them back in the Sr. and they sounded fine. I ordered a matched quad of JJ's from Eurotubes and they sounded great in the GT with no problems. All I can derive from that one experience and no further testing is that my GT must really like matched power tubes.
I have always accepted the fact that to get the level of gain, clarity, dynamics, and harmonics that the GT has you've got to design the amp "on the edge". It's kind of like owning an ultra high performance race car; it takes a little care and feeding
I still LOVE my GT. There's no other amp like it. It's got that whole "Trainwreck" kind of thing but it's much more Marshally and has so much clarity since it's just got a cut control and no tone network.