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Can I plug my vintage Ampeg SVT into an 8 Ohm cab?

Discussion in 'Amps and Cabs [BG]' started by rheohead, Mar 23, 2010.

  1. I have an extra Genz Benz XB cab lying around and I was wondering if it is safe to plug my vintage 300 Watt SVT ('73-'74 - I can't remember) into it. The cab is the original Genz Benz 210T XB that was 250W RMS and 8 ohms.

    I found a thread on TB talking about the SVT with 4 and 2 Ohm loads but I'm not sure what will happen with 8 Ohms.

    Any thoughts?
  2. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    You'll get a few answers here. Some will say the mismatch won't harm it, others will say it will.
    If it were me, I wouldn't do it. But that's me.
  3. nysbob


    Sep 14, 2003
    Cincinnati OH
    I've done it with one of single 15" cabs, but I wouldn't push it real hard or do it constantly. :meh:
  4. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Although the amp will be slightly less powerful it will make for higher plate loading than the the amps original design, it will shorten tube life and may damage your output transformer.
    other than that its fine.
    A 2 X 10 cab for a 300 watt tube head is not the full ticket is it, you will have to be very careful or you will mechanically damage it even if you don't burn the voice coils.:bassist:
  5. anonymous02282011

    anonymous02282011 Guest

    Jun 27, 2007
    Safe? well, sorta.

    The tap on that amp is made for a 4ohm load, and that's going to be your best bet. Especially for long term use.

    I have a 70s SVT that I've used with an 8ohm cab before. I had no issues with this particular cab but every cab is different and a cabs impedence rating is just and average; the actual impedence jumps around a bit as you play.

    I've recently switched over to a 4ohm Berg HT212. I've always felt the amp sounded better at 4ohms in the low end and now I don't have to worry about stressing it out.

    If you do have to use an 8ohm cab, try not to play for too long or too loud.
  6. Grooveman1961


    May 8, 2006
    Let r rip

    No good technical reason not to.
  7. lem8r


    Jan 6, 2010
    It's not harmful for trans and tubes! You just loose some bandwidth and power.
    If you want matched impedance, then plug 8 Ohm cab into 4 Ohm output and pull any(not form same row) pair of output tubes. Than you loose in power but impedance would be close to normal (for rest 4 tubes)
  8. Thanks for the replies everyone.

    I don't gig with this amp. At 86 lbs., it doesn't leave the house! :D

    It is just sitting in the back room with some other gear and I was going to use it to jam along with an accoustic guitar and maybe do some recording with it. I have no intention of cranking this thing. It's more of a collector piece than performance gear. It's in great shape for it's age.

    It sounds like it's best if I just look around for a suitable matching Ampeg cab and complete the set.
  9. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    i prefer to run a 4 ohm cab with mine, but i have never done any damage to it running an 8 ohm cab.
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