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To Tube Or Not To Tube... That Is The Question!

Discussion in 'Amps and Cabs [BG]' started by kdogg, Mar 5, 2008.


  1. kdogg

    kdogg

    Nov 13, 2005
    Ohio
    Okay, so my 1987 SVT-HD, 60 of 500, arrived today, and I'm pretty stoked to fire this baby up! :hyper: 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!
     
  2. Rob Mancini

    Rob Mancini Guest

    Feb 26, 2008
    I've got tubes older than most people on here in my amps that still test as well as the day they were made. You replace the tubes that need it and leave the tubes that still work in there. The only exception is power tubes. With an SVT, you want two matched sets of three power tubes. If one blows, you should either replace it with one that's matched to the other two, or you should get a set of 3. And since 6550's are very expensive, I'd go with the first option when possible.

    I use a place called www.vacuumtubesinc.com because I love NOS tubes and that's pretty much all he sells. But if you get new tubes, it seems like JJ tubes have the hot hand right now.
     
  3. edbass

    edbass

    Nov 8, 2004
    Good plan.
    Be sure to make sure the filter caps are still good, old electrolytics caps can certainly make your life miserable.
    Have the tubes tested before you replace them. Preamp tubes can last a very long time, and while output tubes don't usually last nearly as long, sometimes they do. I have 60's vintage Genelex KT88's that test nearly new, and they aren't in a box, they are in the amps they were put in in 1967. I gig them regularly. Normally, I would at least make sure that you have matched pairs (6 matched tubes, 2 sets of 3 matched tubes, or at least3 matched pairs in your SVT). Several boutique builders intentionally mismatch tube sets in pursuit of tone. It might sound great, the previous owner may have mixed and matched outputs on purpose.
    Probably not. I would at least listen to the amp with the tubes it has in it (if they test strong) and see what it sounds like.
     
  4. edbass

    edbass

    Nov 8, 2004
    Sorry about stepping on your post, Rob. I didn't see you had posted while I was hunting and pecking. :)
     
  5. Rob Mancini

    Rob Mancini Guest

    Feb 26, 2008
    It's cool. Everyone's free to answer ;)
     
  6. kdogg

    kdogg

    Nov 13, 2005
    Ohio
    That's good to hear guys. Just doing some preliminary research, a total retube is going to run into quite a nice chunk of change. On the upside, once done, the amp should scream along for several years. I'll definitely let the tech test the tubes though, and if good, won't worry about them.
     

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