Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

SVT-CL pre amp tube replacement

Discussion in 'Amps and Cabs [BG]' started by burlysluggers, May 18, 2004.


  1. burlysluggers

    burlysluggers

    Nov 6, 2003
    So I've bought a complete new set of tubes for my Ampeg SVT-CL. Everything was going fine until I was left with 2 - 12AX7 PreAmp tubes, and nowhere to put them.

    I have scoured the Ampeg site, and nothing. Someone please help. Where do they currently live, and how do I get to the to replace them?

    I installed 2 - 12AU7's and 1 - 12AX7 in the driver tube section. Where do the 2 - PreAmp 12AX7's go?

    Any help would be appreciated.
     
  2. I have never owned a SVT-CL so I am not 100% sure but in a vintage svt the pre-tubes go in the top part if the head just behind the controls inside the amp. If you open up the amp from the front and flip it upside down you should be able to get at those tubes. Thats how I do it anyway. Hope that helps.
     
  3. DougP

    DougP

    Sep 4, 2001
    The CL only has 4 tubes in it, 2 12AU7s and 2 12AX7s. they are all visible through the vents in the top. Unless there has been a design change recently.

    I just got this CL and i am loving it so far. keep us posted with new tube reviews in this thing please. what kind of tubes did you buy to replace the stock ones with?
     
  4. I have a sneaking suspicsion you don't have an SVT CL, but rather a vintage SVT, which a completely different (and much better) animal. If that's the case, you've got the wrong tubes. Can you post a pic or a link to a pic of a similar amp? Also, if you bought new power tubes, they need to be biased by a tech. It doesn't matter if they're "rated" or tested or whatever, the amp needs to be set up to run them properly.
     
  5. DougP

    DougP

    Sep 4, 2001
    Crap...i read that as SVP-CL...sorry. I am still excited over my new purchase and am retaining the one-track mind.
     
  6. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The preamp tubes go inside the "upper chassis", which is the part with the front panel.

    To replace them, you must remove that chassis.

    While it is possible for you to do the job yourself, If you are having trouble with it, I suggest taking it to a tech to make sure it is correctly biased up and operational. (legalities, legalities).

    Unless there is an overwhelming reason, or you have upgrade tubes, the preamp tubes should last a long time. They may not need to be replaced.
     
  7. burlysluggers

    burlysluggers

    Nov 6, 2003
    Thanks Jerrold. I found and replaced them. I bought some fairly powerful replacement tubes, and now that I have gone throught the replacement process, I will be taking it to a 'pro' to have it properly biased. The last thing I want to do is kill this thing. Thanks for everyones help.
     
  8. sheepdip

    sheepdip

    Apr 14, 2004
    Here is something you might want to do.....Tell the tech to remove the factory POS trim pots and install 5% 40 turn trim pots, the bias will stay at the proper voltage for a heck of a lot longer and your sound will be better longer. :eyebrow:
     
  9. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Strange that Ampeg went and changed the Original SVT when it was already perfect. :eyebrow:
    Why did they do that? The SVT Classic sounds not even close to the Original IMO. :bag:
     
  10. sheepdip

    sheepdip

    Apr 14, 2004
    Probably to make it cheaper, not necessarily better
     
  11. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    We have been through this before..........I think one of the threads DIDN'T get deleted.....

    The short answer is that we wanted to sell enough of them to bother making them. Any product is like that, if you can't make money you don't bother. A "vintage-exact" version was considered to be very high priced, if even possible, and unlikely to do anything but lose money overall, even if its cool.

    Someone is buying the SVT-CLs. If that stops, we won't make any more. It is that simple. Kinda like playing music, it's fun, but you still want the bar owner to fork over the cash.

    The SVP-CL is the older style preamp. If that does well, there may be a re-consideration of things. Of course, the SVP-CL might also cut into sales of a "vintage exact" SVT.....who knows?
     
  12. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Didn´t mean to start a war. Just curious. To bad it would be to expensive. Maybe a limited edition. But I would probably not be able to afford that. :D I´ll definately check out this new preamp when I see it in Sweden.
     
  13. I'm taking a peek at a modern SVT manual right here and it indicates that it has (3) 12AX7s and (2) 12AU7s ... :confused: