Power Amp Problem ?

  • Got exactly the same problem with power amp output, happened last week for a minute then worked fine, this weekend same issue but didnt fix itself
    Just checked cab and cables with another amp all working fine, all other outputs on kemper working correctly

  • If there is any issue with the output of the power amp (=Speaker Output) - being it loss of volume or noise or completely dead - check the signal of the Monitor Output. The line level signal of the Monitor Output is also feeding the built in power amp internally.


    If the signal of the Monitor Output is ok and the power amp output signal isn't, there is something wrong with the power amp or the speaker cable or the speaker cabinet.


    Normally it is sufficient to plug headphones into the Monitor Out. You should hear a signal on one side, which should be sufficient to evaluate if the signal is ok or not.

  • If there is any issue with the output of the power amp (=Speaker Output) - being it loss of volume or noise or completely dead - check the signal of the Monitor Output. The line level signal of the Monitor Output is also feeding the built in power amp internally.


    If the signal of the Monitor Output is ok and the power amp output signal isn't, there is something wrong with the power amp or the speaker cable or the speaker cabinet.


    Normally it is sufficient to plug headphones into the Monitor Out. You should hear a signal on one side, which should be sufficient to evaluate if the signal is ok or not.


    Hello Burkhard,


    Sorry to resurrect an older thread, but I was wondering what would happen if the power amp in my KPA PowerRack were to fail. I did a quick search, and came across this thread.


    Now, just to be clear, everything is fine and dandy. No problems, and I am coming up on 3 years.


    However, I was curious about the failure mode of a powered unit like mine, if the IcePower power section were ever to give up the proverbial ghost. In your experience, does such an occurrence sometimes take down the entire unit...or is it more than likely that I will still be able to use my KPA PowerRack by connecting via Monitor Out to a powered FRFR? I am not asking for a definitive answer, as I am sure there are multiple failure modes for the power module...however, i am just curious if you have any anecdotal information and experience in these cases. My concern is that if the power amp goes belly up, I would get a catastrophic error message on the display, and wouldn't be able to use the KPA at all.


    Thanks in advance,
    John

  • The cases I'm aware of, if the power amp breaks because of wear, all the rest keeps working. However there are other hardware (CPU, DSP,...) defects which could have wider implications. In any case you should avoid to connect the power amp's Speaker Output to any grounded gear like active power soaks or a line level input of a powered wedge,... That could damage the internal power amp and even other components.

  • The cases I'm aware of, if the power amp breaks because of wear, all the rest keeps working. However there are other hardware (CPU, DSP,...) defects which could have wider implications. In any case you should avoid to connect the power amp's Speaker Output to any grounded gear like active power soaks or a line level input of a powered wedge,... That could damage the internal power amp and even other components.

    Hello Burhard,


    Thanks for the info., and your quick reply. It is greatly appreciated.


    Indeed, your final point is well taken, and something I am always careful about.


    Cheers,
    John

  • Hi, I'm pretty new to Kemper although had some experience with modeling. I tried out everything that's mentioned in this thread but to no avail. This is my problem: newly arrived Matrix FR12P (passive FR, 300W, 8 Ohms) connected to Monitor Out of Kemper Poweramp gives very low and distorted level. All output settings in the Kemper seem correct to me. When I connect the FR12P to my VOX amp with the same cable (jack to Speakon), works perfectly. The output on the VOX for an extra cabinet is 30W - 8 Ohm. But... also when I connect headphones to Monitor Out Kemper all sounds normal and the same as through the Main Outs on my studio monitors! I'm not really good at the Ohm versus Watt thing (I always played on combo amps) but does pure deduction lead me to the fact that there's an incompatibility between the power amp of the Kemper (manual says 600W at 8 Ohms, 300W at 16 Ohms) and the Matrix FR12P (300W at 8 Ohms) which causes the problem? If so, is there any remedy which is not 'buy another FR speaker'? Thanks for reply.

  • Hi, I'm pretty new to Kemper although had some experience with modeling. I tried out everything that's mentioned in this thread but to no avail. This is my problem: newly arrived Matrix FR12P (passive FR, 300W, 8 Ohms) connected to Monitor Out of Kemper Poweramp gives very low and distorted level. All output settings in the Kemper seem correct to me. When I connect the FR12P to my VOX amp with the same cable (jack to Speakon), works perfectly. The output on the VOX for an extra cabinet is 30W - 8 Ohm. But... also when I connect headphones to Monitor Out Kemper all sounds normal and the same as through the Main Outs on my studio monitors! I'm not really good at the Ohm versus Watt thing (I always played on combo amps) but does pure deduction lead me to the fact that there's an incompatibility between the power amp of the Kemper (manual says 600W at 8 Ohms, 300W at 16 Ohms) and the Matrix FR12P (300W at 8 Ohms) which causes the problem? If so, is there any remedy which is not 'buy another FR speaker'? Thanks for reply.

    You need to connect this passive cab to the red speaker output, not the monitor output.

  • You need to connect this passive cab to the red speaker output, not the monitor output.

    Waaw, glad it's that simple, thanks a lot Ingolf :) . There's hardly anything in the manual of that Speaker Out, it's always Monitor Out this'n'that (or I've totally overlooked it). Thanks again, saved me some headache over the weekend!

  • Hi, I'm pretty new to Kemper although had some experience with modeling. I tried out everything that's mentioned in this thread but to no avail. This is my problem: newly arrived Matrix FR12P (passive FR, 300W, 8 Ohms) connected to Monitor Out of Kemper Poweramp gives very low and distorted level. All output settings in the Kemper seem correct to me. When I connect the FR12P to my VOX amp with the same cable (jack to Speakon), works perfectly. The output on the VOX for an extra cabinet is 30W - 8 Ohm. But... also when I connect headphones to Monitor Out Kemper all sounds normal and the same as through the Main Outs on my studio monitors! I'm not really good at the Ohm versus Watt thing (I always played on combo amps) but does pure deduction lead me to the fact that there's an incompatibility between the power amp of the Kemper (manual says 600W at 8 Ohms, 300W at 16 Ohms) and the Matrix FR12P (300W at 8 Ohms) which causes the problem? If so, is there any remedy which is not 'buy another FR speaker'? Thanks for reply.


    deeBee,


    As per @Ingolf answer, this information can be found on page #20 and 23 of the KPA Basics Manual,
    I agree that it may seem a bit confusing, at first, because of the internal link between the Speaker Output and the Monitor Output (and the manual refers a lot to the Monitor Output). The manual could be a bit more clear on this matter. But yes, you definitely want to use the Speaker Output when connecting to a passive (i.e. non-powered) monitor or guitar cabinet.


  • What did you "put to max"? Master Volume, Monitor Output Volume, Power Amp Boost,...?

    Is it affecting the SPEAKER OUTPUT only and not the MONITOR OUTPUT?

    Have you tested another input - ALTERNATIVE IN instead of Front INPUT or vice verse with Input Source set accordingly?

    Are you running OS 6.0?