Okay, so my 1987 SVT-HD, 60 of 500, arrived today, and I'm pretty stoked to fire this baby up! Unfortunately, my speaker cab is down at my band's practice space, and so I'll have to wait a day or two. I want to take the amp to my local tube guru anyway, before actually gigging with it. My question is, and be gentle, I'm new to the vintage tube amp thing, is should I have the amp retubed? 3 of the 6550's are the original SLM's, 1 is an RCA 6550, and the remaining 2 are larger than the first 4 and have no markings on them. These last 2 also look almost brand new. The preamp and driver tubes all look original, accept for two 12AX7's which have been replaced with Groove Tubes. Any and all suggestions welcome, including replacement tube manufacturers, if that should be the route to go. Thanks guys!