Can I safely have two bass amps plugged into one cab?

Discussion in 'Amps and Cabs [BG]' started by keyboardguy, Mar 18, 2023 at 2:49 AM.

  1. keyboardguy

    keyboardguy Supporting Member

    May 11, 2005
    Hi folks;
    I want to try out two different non-tube bass amps into the same cabinet to compare each amps' sound. (A GK amp and a Peavey)

    The 8 ohm cab has 2 speakon inputs.
    Can I have both amps plugged in and turned on, but only ONE has the volume turned up? (the other has volume turned completely OFF.)

    That way I can listen to amp 'A' while amp 'B" volume is off, then quickly turn down 'A' and turn up 'B'.
    Will this harm the amps or cabinet at all?

    DJ Bebop likes this.
  2. Jogobass


    Feb 5, 2013
    Groningen, NL
    Intuitively, don't do this. You're connecting two power amps to each other. Doesn't matter that the volume is down. Maybe someone more knowledgeable knows for sure. Just giving the safe answer.
    seamonkey, DJ Bebop and MCF like this.
  3. Matthias


    May 30, 2000
    Vienna, Austria
    No, never do that. You will likely damage both amps, even if one of them is powered off!
    Last edited: Mar 18, 2023 at 3:30 AM
  4. Arthur U. Poon

    Arthur U. Poon

    Jan 30, 2004
    SLC, Utah -USA-
    Endorsing Artist: Mike Lull Custom Basses
    No. Don’t try it. You’ll quickly damage both amps.
  5. Coot


    Nov 14, 2018
    Get an A/B/Y switcher from Radial . You will need two full rigs, two amps and two cabs . Rent a similar cab for the experiment and you can A/B the heads that way. You can damage your equipment trying to A/B two heads into one cab. IMO
  6. Lance Bunyon

    Lance Bunyon

    Jul 17, 2018
    Just switch your load manually. For safety, use only one cable and switch it powering off the amp that doesn't have a load anymore. Plugging two amps into one cab will guarantee a silent (broken blown) cab pretty quickly.
  7. RichSnyder

    RichSnyder Columbia, MD Supporting Member

    Jun 19, 2003
    No. The second speaker jack on the speaker is for chaining a second cabinet. Plugging two amps into them is basically like plugging the amps into themselves.
  8. Can I safely have two bass amps plugged into one cab?

    mcnach, Spectrum, HolmeBass and 17 others like this.
  9. Can I safely have two bass amps plugged into one cab?


    Two amps into one speaker? One amp on, signal going into speaker, signal also going into second amp plugged into same speaker...


  10. MCF


    Sep 1, 2014
    DJ Bebop likes this.
  11. MCF


    Sep 1, 2014
    Funny how that GK cab post looks like the guy ran both outs from the head to a single cab. Is it the moon or something?
  12. But that is something that can survive another day. This is something that is calling on the magical smoke to appear.


    dkelley, BlueTalon, Schlyder and 2 others like this.
  13. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    This was a topic about 10 years ago where Robert Gallien replied and said that doing that is unusual and didn’t think there was a benefit but it won’t hurt anything. But that’s one amp, not two. Huge difference.
  14. Grinderman


    Dec 21, 2013
    Los Angeles
  15. The easy answer is, all you need is a speaker-level A/B switch (not a line-level switch as some here have recommended). This would connect only one amplifier (A or B) to the speaker cabinet.

    The problem is that pretty much all the switches of this type on the market also include an A+B selection, which would connect both amps to the speaker at the same time. Of course, from what I’ve always heard this will damage the amplifiers if you accidentally moved the switch to that position.

    Another issue with these devices is that they typically require hard-wired connections and don’t accept standard 1/4" or Speakon connectors. So, you’d have to cut up three cables to make it work.

    Really, it wouldn’t be hard for someone to make a device like this, with a project box, female 1/4” or Speakon connectors, and a double-pole, double-throw toggle switch.

    Wayne A. Pflughaupt

    Ecclesia: Unique Arrangements of Hymns, P&W Standards, and Original Tunes
    Administrator, Pedulla Club #45
    Administrator, Official Tobias Club #133
    Fretless Club #943
    Big Cabs Club #23
    My Rig: Stage and FOH Friendly
    My Basses
    DJ Bebop and CTW68 like this.
  16. DWBass

    DWBass The Funkfather

  17. Any attmpt down this path will lead to lots of damage. Just don't go there.
    DJ Bebop and BlueTalon like this.
  18. CosmicRay

    CosmicRay Supporting Member

    Strongly advise not to do such a thing.
    DJ Bebop likes this.
  19. john m

    john m Supporting Member

    Jan 15, 2006
    My money is on the speakers surviving and the amplifiers getting wiped out.
    HolmeBass and DJ Bebop like this.
  20. Ric5

    Ric5 Supporting Member

    Jan 29, 2008
    I like 5, 8, 10, and 12 string basses
    Can I safely have two bass amps plugged into one cab?

    The best case scenario is it will be a tone suck, the worst case scenario is it will kill one or both of the amps
    HolmeBass and DJ Bebop like this.