do tubes/valves in amps determine most of the sound?...if so which would be a good buy for an orange TT.

just been looking around and the mesa boogie ones are one of the most expensive....are they any good?

the TT tales 12AX7 x2 and EL84 x2

No, the Tubes don't determine the majority of your tone, I would recommend JJ tubes, They are cheap and good, or you could also go to the "Everything you wanted to know about tubes" thread
Quote by Kensai
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Tubes DO NOT determine most of the sound. Changing the tubes will tweak the sound a little bit.

Mesa tubes aren't even close to the most expensive tubes, you're just not looking hard enough. A pair of NOS mullard EL84s cost ten times what Mesa charges. There are sites besides Musician's friend, you know

Anyway, Mesa tubes are just rebranded tubes, so forget about those. I'd get all JJs for the TT, they might help tame the fizziness.
JJ's have quality control issues. Some people get good ones, but an alarmingly high amount of people get DOA or ones that bust soon after purchase.

Stick with TAD, Winged =C=, Tung-Sol, Mullard, Electro Harmonix.

I like Tung-Sol and Penta for preamp.