Are there any cabs I SHOULDN'T plug my Powerrack into?

  • Well, I've gone and ordered the Kemper Powerrack! Arriving next month, I'm very excited. Rehearsal rooms tend to have passive guitar cabs in them, so I intend to plug it in to one of those. There's various reasons why I'm not going into the PA in this instance!


    Only... I'm a little nervous. A year and a half ago I had a nightmare just before a show where I literally fried my bass amp head (Spoiler alert - don't plug two heads into one cab!). It's got me very paranoid about plugging heads into cabs - especially the £1800 Kemper I just ordered. If I broke it, I wouldn't be able to afford the repair.


    I know almost nothing about guitar cabs, so before I Are most guitar cabs created equal? Can I safely plug into every guitar cabinet with the Kemper and know it'll work, or do I need to find out the cab's specs first? Do you know of any cabs you can't plug the Kemper into?


    And finally, say I unplugged the cable from the cab's side but left it in the Kemper - I heard that that damages a regular amp. Not sure if there's truth to that, but what happens if I do that to a Kemper? Is it okay to do that?


    I'm sorry I have so many questions. I just really do not want to break this thing.

  • You can plug the kemper into any cab. It’s 600 Watts so make sure the speakers in the cab can handle a lot of power and keep the volume low if they can’t. If you keep the kemper’s Power amp boost at 0, then the kemper can pretty safely work with a 150 watt cab at max volume.


    Note that if the power exceeds the power rating of the cab the speakers might blow but the kemper itself should be fine.


    It will not be damaged if you unplug the cab while it’s on (a regular amp will).


    There are usually 16, 8 and 4 ohm cabs. The kemper works with any of them but towards maximum volume a 4 ohm cab might try to draw too much power from the kemper. The kemper will automatically shut off in this case but should be undamaged. This will only be when it’s very loud.


    With the kemper you are more likely to damage a guitar cab (at loud volumes) than the kemper, which is quite advanced and should protect itself.

  • Impedance and power are inversely related. The Kemper puts out up to 600w at 4ohms or 8ohms but only 30pw at 16ohms. This won’t make a difference to the safety of the Kemper itself but it does mean you might need to keep the output level on the Kemper lower to protect the speakers if the cabinet is wired for 4 or 8ohms than you would with a 16ohm cab. Just be sensible with the volume level and you should be fine with pretty much any passive cab.

  • And if you use Direct Out + Monitor Out (preserving the stereo fx) and send these 2 outputs to 2 mixing desk inputs and from there to 2 powered speakers of 1000 W each? For monitor reasons. Does the affect the impedance of the used speakers. Does this way of connection sound different from Main outputs (jack or XLR?) to FOH ?

  • And if you use Direct Out + Monitor Out (preserving the stereo fx) and send these 2 outputs to 2 mixing desk inputs and from there to 2 powered speakers of 1000 W each? For monitor reasons. Does the affect the impedance of the used speakers. Does this way of connection sound different from Main outputs (jack or XLR?) to FOH ?

    This is possible and will sound the same as the Main Outputs as long as Monitor Outputs are set to Master Stereo (the same as the Main Outs should be set).