Dual Amp setup. What do I need to look out for?

Discussion in 'Amps and Cabs [BG]' started by pbass6811, Feb 3, 2018.

  1. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    Ok, so I've been totally inspired by @bass40hz . I wanna try a dual amp setup. Other than having matching amps, I have everything I need to get this done. My question is what kinds of things do I need to be wary of and look out for? For now, I'll be using a Quilter BB800 and a Mesa D800+ and running them each Through separate Ampeg PN-410s. What potential disasters do I need to keep an eye out for? I'm probably going to try this tonight, at one of our high profile gigs, lol!

    Other than the fact that the amps sound different, what could go wrong??
    bass40hz likes this.
  2. JRA

    JRA my words = opinion Gold Supporting Member

    nothing. absolutely nothing. :roflmao:

    seriously: i've bi-amped, tri-amped, double-amped...i've probably tried all of the various combinations at one time or another. i think the only thing you'll find out is: whether it's worth the effort. IME: it seldom was! YMMV. good luck tonight! :thumbsup:
  3. BadExample


    Jan 21, 2016
    Label your speaker cable ends. Go ahead, we'll wait. There was a sad thread a few months ago where an experienced bassist on a dimly lit stage plugged one amp output into another. Poof. The smoke got out and you can't get it back in.

    If your amps and cabs all use common connectors, this is especially important. Like if they all have speakon jacks. If you grab two ends from a mass of cables and accidentally plug one amp into the other, rather than the intended amp->cab connection, this thread will have a very sad ending. One amp trying to drive the output of another is a sure path to an expensive repair bill!
    Steve-Mo, ELG60, agedhorse and 3 others like this.
  4. seamonkey


    Aug 6, 2004
    Are you trying to do stereo?
    Or are you just looking to get louder?
    If you prefer one pre-amp, Send the preamp out of one amp to the effects return, aux in of the other amp.
    It won't be the same as a power-amp, but a lot less knobs and interference to keep track of.
  5. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    Cool. The way I'm looking at this is, I'm actually only schlepping one more cab. Everything else is always at every gig...

    Right on. Thanks for the heads up. I will definitely keep an eye on what's plugged into where. Thanks!
    BadExample and JRA like this.
  6. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    Hey. Nah, I'm not looking for stereo setup. I guess it's more of a wet/dry setup. One amp will be straight bass, the other amp gets the pedalboard...

    It makes sense in my head. Lol!
    Michael4bass and Fuzzonaut like this.
  7. The resultant phase responses to the bass input may become unpleasant by small or large degree. Individual perception may differ.
    Lvjoebass, BadExample and pbass6811 like this.
  8. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    That's what I'm concerned about with using two different amps. If they were both the same, it might not be as much of an issue. I'll letcha know. Thanks.
    Lvjoebass and BadExample like this.
  9. Not just the amps but the effects also.
    ihixulu, agedhorse and BadExample like this.
  10. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    The good thing is, if it sounds like crap, I can chalk it up to a learning experience and shut off one of the amps. No worries.

    I'm thinking that the worst that will happen is it sounds like @$$ and then I can move on.
    BadExample likes this.
  11. BadExample


    Jan 21, 2016
    To me it's fun to experiment with stuff like this. If worse comes to worse, you could power them both off and plug your cabs into one of the two heads. If you like it, check out the Crown XLS power amps. Each channel has independent HPF and LPF filters, so you can send clean to one channel, dirty to the other, and enjoy the yummy goodness :D I think I'll be heading in that direction. Something is really appealing to me to be able to just plug in a different preamp to change things up.

    Crown XLS 1502 Power Amplifier I'm pretty sure Sam Ash Castleton stocks these if you wanted to plug in and try it. Very nice people in that store.

    There was a very sad thread, maybe last fall or summer, where someone plugged one amp output into another on a dimly lit stage. Ate both amps :( It was a sad thread :( That's why I mentioned labeling the ends of the cables. It would really suck to kill two nice amps and be left with nothing :( I already labeled my cables... I'm kinda thick. You know how Purdue employees are :D BTW: just noticed your location, I'm just down the street from you... an hour N. on 65.
    Lvjoebass and pbass6811 like this.
  12. Your back? The paint in the stairwell? Your very small and underfoot dog? Just trying to think of everything that would go wrong if I tried this.
  13. Direct Box Rox

    Direct Box Rox Silence = Deaf

    Feb 12, 2012
    I would say, nothing. My live rig was two Eden WT-300's. One into an SWR 8x8 and one into an SWR 2x12. I plugged my Zon bass into the heads at the same time via a Y-cord and EQ'd each cabinet separately. Never ran into any issues.
    Last edited: Feb 3, 2018
    pbass6811 likes this.
  14. mpdd

    mpdd neoconceptualist

    Mar 24, 2010
    generally, i think one amp is supposed to sound clean through 12s or 15s, while the other is supposed to be distorted through 10s, or at least that's what i've read
    pbass6811 likes this.
  15. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    Yeah, I think these things are cool to try, especially since I didn't hafta buy anything to give it a shot. So, you're in the Lafayette area? We play at a joint called Ace's Pub there in Lafayette. I've got nothing but love for Purdue, my oldest daughter just got her Master's from there.

    Fortunately, all my cabs are Neo's, the heaviest amp I'm using is 6lbs, the only stairs involved are the three leading up to the stage, and the cat know better than to stand near me while I'm schlepping gear, because I will strap a cab to his back and make him earn his keep...lol!

    That sounds killer! I always loved the Eden and SWR gear I owned.

    Right on. I'm not trying to get into "that" debate, but I am a diehard, unapologetic matching cab proponent. I'll always try matching cabs first...
    toddbooster, Direct Box Rox and mpdd like this.
  16. Wasnex


    Dec 25, 2011
    Using matching cabs should eliminate most phase related problems, but keep in mind EQ introduces phase shift as well. Greater boost or cut means greater phase shift. Probably minimal impact such as reduced clarity and uneven tone.

    Some pedals invert signal polarity 180 degrees which can result in cancellation in the low end and comb filtering across the audio spectrum. This would likely produce a quite noticeable loss of low end and volume.

    Digital effects have latency that equates to a slight signal delay which can cause comb filtering. Impact would probably vary with the type of effect used. Perhaps perceived as a slightly annoying mid range resonance.

    If you have FOH support an additional channel will be required for bass.

    If you are using several effects it could be quite time consuming to dial them in given you haven't used this sort of setup before. I would play around with the setup at home, work out the kinks in rehearsal, and use it live after I had a good feel for how to dial in the various sounds. YMMV

    Additional Ideas for later
    If you have the option, consider experimenting with pre distortion EQ and post distortion high pass and low pass filtering on your wet rig. Ideal EQ and band pass settings could vary from one effect to another.

    It is likely, some effects will sound better running parallel wet/dry amps, and some will sound better running wet on both amps. The range of possibilities with signal switching is endless, so have fun and good luck.
  17. pbass6811

    pbass6811 Supporting Member

    Nov 10, 2008
    Indy, IN
    Holy cow! That was a phenomenal breakdown of what things to look for! Thank you! I didn't even think that some stuff would benefit from running through both amps. That's super cool. I'll probably go ahead and try it tonight, since it's pretty much all I've been thinking about today, lol, but you've given me lots of food for thought. Well played, sir...
    DrummerwStrings and Wasnex like this.
  18. Wasnex


    Dec 25, 2011
    I am sure everyone looks forward to the gig report:bassist: :thumbsup:
  19. I do this all the time! My second amp is called "the PA system"...
  20. DrummerwStrings


    Mar 27, 2015
    Can put bright colored tape around the cable ends too as a backup.

    EDIT: I initially thought above-referenced post said 'label the cabs'.
    Last edited: Feb 3, 2018