Recommend power tubes for an SVT?

[Andrew]

Hey PBG (or anyone else who can help),
    Can I get a recommendation for a set of power tubes for my '73 SVT? 6550 or KT88 is fine.

Also, has anyone tried the Tung Sol KT120? Could an old SVT handle a set of these without modding, and would they make a difference in the amp's output?

Thanks!

[Psycho Bass Guy]

I've been meaning to try the KT120's, but between work and my extended illness (cancer was just the latest part), I haven't had the chance. I have heard of them being run safely in a Marshall Major which has no where near the robust heater current of an SVT, but that's just anecdotal. I'm still a huge fan of the Sovtek KT88/Tungsol 6550 if you don't want to experiment. 

[rahock]

I don't have an SVT so I'm kinda talking through my ass, but a couple of buddies who have had SVTs since the 70s like the Sovtek 6550s. They tried a few others but prefered the Sovteks for both sound and dependability.
Rick