Hooking up to a guitar cab

  • Hi everyone,


    I have been playing guitar for nearly 30 years so you'd think I know this stuff but here goes....


    I want to try my KPA through a 410 cabinet that I have, but I'm worried about damaging the amp (and speakers, but less so!) so I thought I'd
    check with you pros first.


    The cabinet says "8 ohms total - 120 watts"


    I am tempted to just plug it in and see what happens, but is there a place somewhere in the KPA where I have to set the ohms to match
    the speaker cabinet, or does the KPA somehow know how to do this automatically?

    I have been looking around for a couple hours trying to educate myself about this stuff, and while I think it will be fine I just want to get some
    expert advice before plugging it in. I have always played Fender combo amps so this has never really been something with which I needed to concern myself.


    Thanks so much.


    Calaban

  • Hey Calaban,


    I assume you own a powered Profiler.
    8 ohm is the most common load for a power amp, so no problem under this respect. But keep volume low! 120 watt is much lower than the maximum power the Kemper power amp can output.


    In case you've got the passive Profiler, you'll need an external power amp.


    In general, a SS power amp just outputs more voltage the lower the cab's impedance (up to a poin) and the other way round, and doesn't need any setting.


    :)


  • Viabroce...thanks for your help again!


    Yes, I own the Power Rack.


    So I got it hooked up and I'm getting sound, although it's not good.


    - Monitor Cab turned OFF in Output settings.
    - Stomps are audible when turned on and off, but the Delay and Reverb effects are not. Do I have to route them to the Monitor Out somehow?
    - Volume is set correctly I believe....the Output LED is not hitting the red, but Master Volume is all the way up and it's still rather quiet.


    The overall tone is not good at the moment, but I think that is user error at this point! Maybe it's just a really bad cabinet?


    Any thoughts?


    Thanks again...you've been a great help!


    Calaban

    Edited once, last by Calaban ().

  • Yes, I own the Power Rack.


    So I got it hooked up and I'm getting sound, although it's not good.


    - Monitor Cab turned OFF in Output settings.
    - Stomps are audible when turned on and off, but the Delay and Reverb effects are not. Do I have to route them to the Monitor Out somehow?
    - Volume is set correctly I believe....the Output LED is not hitting the red, but Master Volume is all the way up and it's still rather quiet.


    1. make sure that monitor out is set to master mono in the output menu. You should hear delay and reverb now.
    2. use the volume boost function to make it louder.



    The overall tone is not good at the moment, but I think that is user error at this point! Maybe it's just a really bad cabinet?


    It's not easy to determine why that is.
    Maybe describe the sonic characteristics of your cab. Speakers' brand etc.?

  • In order to evaluate the overall sound quality and do some troubleshooting, use just an amp and no fx whatsoever, and check that nothing is locked.


    How is the sound via headphones? Had you already used the Profiler before? Can you connect it passively (i.e., skipping the power section) to some active monitors/PA/bass amp/keyboard amp/acoustic amp?


    Also, try with cab on... You might be surprised :)


    Let us know

  • Thanks for all the help guys.


    It is now too late to try the cab in my apartment, but I will try again tomorrow and follow some of your suggestions.


    To answer your questions:


    -It's hard to describe the sonic characteristics of the speakers themselves, since I haven't used them in 10 years or so. They came with a Reverend Hellhound amp head, and they are made by Joe Naylor. The Hellhound is a switchable 40/60 watt amp. The speakers themselves are 30 watts each. Is it possible they just can't deal with the watts the KPA is putting out? I stopped using the amp years ago because after a couple months I decided I don't really like the sound of 10" speakers. I just figured since it's the only cabinet I have lying around I'd give it a shot.


    - I have been using the KPA with headphones for the past week with great results....everything sounds amazing and as it should.


    - Unfortunately I don't have any active monitors/PA/bass amp/keyboard amp/acoustic amp to try it with.


    - I tried it with cab on and the results weren't much different...it was slightly muddier but the volume wasn't any louder.


    - I feel that I should not have to use the volume boost function...shouldn't the amp be loud enough? I mean, it's really quiet. My Reverend amp used to rattle the windows.


    The biggest problem that I can see is that it's just not as loud as I think it should be (I couldn't get it past quiet bedroom levels) and the effects don't seem to be working. I will try the suggestions tomorrow.


    Thanks again for the help!


    Cal

  • There must be something routed incorrectly in the Output section. Believe me, it's loud enough! I have a PowerRack, and I never turn it up past halfway with my 2X12, if I even get past a quarter!!


    Cheers,
    Sam

  • Ok I've had a little more luck today but not much.


    I am using the Morgan AC20 profile from (I believe) rmpacheco. Great sounding profile in the headphones!


    -I got the effects to work so there's some progress (Thanks Ingolf)


    -It still is not loud enough, and even when I turn the gain on the profile down to 0.0 I get distortion if I try to bring the volume up. The master V = 5.0, regular V = 0.0...if I try to turn it up any louder the sound gets distorted (keep in mind I'm trying to get a clean sound for now....but it just doesn't seem possible at a decent volume)


    -I tried the Power Amp Boost (it was set to +6 dB already) but I also got distortion if I turned it up. In fact I had to turn it down to 0.0 to get rid of the distorted tone.


    So it seems like I simply have zero clean headroom. At this point I feel that this speaker cabinet just isn't up to the task but if anyone has any other suggestions I'd be glad to try them out!

  • Well, if the outputs are set correctly and you're using a decent quality speaker cable that isn't defective, then either there's a fault with the poweramp or connector, or the speakers are faulty. As they haven't been used in 10 years, I'd be looking at the speakers first.


    Cheers,
    Sam

  • Well, if the outputs are set correctly and you're using a decent quality speaker cable that isn't defective, then either there's a fault with the poweramp or connector, or the speakers are faulty. As they haven't been used in 10 years, I'd be looking at the speakers first.


    Cheers,
    Sam


    Two thoughts:


    1. I think the outputs are set correctly but they may not be! I am so new to the digital world that I just may not be doing it correctly. What I am discovering is that there are so many different volume controls that I'm getting a bit confused! The manual doesn't really give a step by step guide to setting input and output levels so I'm really just guessing. Can anyone offer some guidance?


    2. I read in the manual that there is switch available to turn off the power amp....my unit does not have this. Is it only on the Head version and not the Rack version? The reason I'm asking is that maybe they sent me the wrong unit and I don't even have a power amp! Now....please excuse my ignorance here...is it possible for the unit to make sound at all through a passive cabinet if there is no power amp?

    • The "switch" to turn your poweramp off is software switch. You find it when you push "output" and than find the page with it pushing "page" buttons
    • Check in the same output section, if you Master at Monitor out is linked to Master
    • Look at output led, if it is red you clip.
    • Try this:
      – Rig Volume at noon (this volume knob is only to match the volume between presets)
      – Power Amp Boost: +6dB
      – now with Master at 4–6 you have more as enough loudness (eg with live drummer, even if the cab is 16 Ohm)


    When you test, first turn all effects off, than try it with effects, perhaps you have some boost here too.


    If you have speaker output on the back – with red ring, and printed 8–16 ohm – you have power amp :)

  • HAHA I figured it out.


    I swear sometimes I'm not the sharpest tool in the shed...


    This is what clued me in:


    "If you have speaker output on the back – with red ring, and printed 8–16 ohm – you have power amp :-)"


    I had been using the MONITOR OUT into a PASSIVE cabinet!!!


    So...finally taking my head out of my butt, I went from the MAIN OUT into the cabinet and it sounds brilliant!


    I still need to learn a lot about the different output setting to make sure I have it all set correctly, but right now there are no LED's clipping and it's loud and luscious!


    Thanks for your patience...you have all been so helpful!


    Silly me....


    Calaban

  • Is there a knot in my brain? A powered Speaker Output = ok, but the Main Outs are powered while the Monitor Out isn't? Why should the Main Outs (which normally go FOH) be powered, if there's a powered Speaker Output?

    I could have farted and it would have sounded good! (Brian Johnson)