'72 Ampeg SVT

Discussion in 'Amps and Cabs [BG]' started by braun-jovi, Jan 11, 2005.

  1. braun-jovi


    Mar 25, 2004
    Evansville, IN
    I just got a '72 Ampeg SVT. On the back it asks for a four ohm load from the main output and a four ohm load from the extention speaker. Does this amp want to run at a two ohm load? and if it does want to see a four ohm load, do I run cable from my first eight ohm speaker to my second or will i be fine running both from the main and ext speaker outs? sorry for the ignorance and thanks in advance.
  2. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Early ones used a 4 pin connector for the main 4 ohm speaker, and plugging a speaker into the standard extension speaker jackautomatically switched to the 2 ohm tap.

    Later units have had switches to set the tap.

    Also, double 1/4 inch jacks were used with automatic switching.

    So, assuming no switch, and both as 1/4 inch jacks, which I think is right for yours, you should be able to use a 4 ohm speaker on the main out, which you would use if only using one speaker.

    If you use two, plugging the second (also 4 ohm) speaker into the extension jack does the switching to 2 ohms for you.

    Unfortunately, units have been "modified" in various ways over the years, so without seeing yours I can't be absolutely sure.
  3. braun-jovi


    Mar 25, 2004
    Evansville, IN
    You are correct, there is no switch and it has two output jacks.

    Also, both of my speaker cabinets are 8ohm. Would I be better off running into one of them, then out of it to the other speaker cabinet or do I use the extention speaker jack and it will switch it to a 4ohm load?

    Thanks for your response, it's greatly appreciated.
  4. The ONLY way you should run your amp is to take the "speaker out" line into one cab and then daisy chain the other off that cab. If you try to use the "extension speaker" jack at all, you'll trip an internal switch and your amp will be expecting a 2 ohm, not 4 ohm load.
  5. braun-jovi


    Mar 25, 2004
    Evansville, IN
    Thanks PBG. That's what I was thinking, just wanted to make sure.