Active Cab Question

    1) First off I am using the powered Kemper head so I assume i'll need to turn the power amp off in the unit or do you know from experience that the powered kempers recognize it's plugged into a powered cab and bypasses it?


    2) It seems like using a mic cable would provide best results in connection from a pro audio standpoint but do you have any preference? It looks like there's 3 XLR inputs on the back of the cab but it's a 1x12 so is there a benefit to running two XLR's? Here's the link to the Cab i'm getting. https://xitonecabs.com/product/mbritt/

    Quote from GuyJames

    1) First off I am using the powered Kemper head so I assume i'll need to turn the power amp off in the unit or do you know from experience that the powered kempers recognize it's plugged into a powered cab and bypasses it?


    2) It seems like using a mic cable would provide best results in connection from a pro audio standpoint but do you have any preference? It looks like there's 3 XLR inputs on the back of the cab but it's a 1x12 so is there a benefit to running two XLR's? Here's the link to the Cab i'm getting. https://xitonecabs.com/product/mbritt/

    1) NEVER plug an active cab in the RED speaker output of the Kemper. This will damage your cab. Use the monitor out instead. You can turn off the Kemper's power amp in the output menu, but it's not mandatory.


    2) Like I said before, I'd use the monitor output in order to be independent from the main output which goes to FOH.

    @Ingolf


    Thank you man, I didn't think about it but your point made about using monitor out so I still have the XLR's put it in perspective. Do you have any preference on instrument cable you use? I'd imagine the shortest possible vable would be ideal. I use the George L's that I could make a 1 foot cable.

    Quote from GuyJames

    @Ingolf


    Do you have any preference on instrument cable you use? I'd imagine the shortest possible vable would be ideal. I use the George L's that I could make a 1 foot cable.

    Well, the monitor out sends a line level signal, therefore cable length doesn't actually matter (the profiler effectively is a buffer). I always use high quality (though no boutique high price quality) guitar cables (like Cordial etc.), up to 6 m length.

    Quote from Ingolf

    1) NEVER plug an active cab in the RED speaker output of the Kemper. This will damage your cab. Use the monitor out instead. You can turn off the Kemper's power amp in the output menu, but it's not mandatory.
    2) Like I said before, I'd use the monitor output in order to be independent from the main output which goes to FOH.

    Even worse: connecting a powered speaker, which is grounded, to the Speaker Output of the built in power amp would seriously damage the power amp!!! Don't do that! Warning in the manual.

    Well line level doesn't really matter so much - this unbalanced circuit (running from the monitor out to a cab via a guitar cable) has pretty significant limitations as soon as the cable length is more than a few feet.


    A guitar cable with 1/4" jacks will damp the high frequencies progressively more the longer the cable run. In theory, the cable acts as an RC low pass filter where C = capacitance (which will have a value per meter of cable - as the links below show, the capacitance per foot of different cables varies quite a bit) and R is resistance (which will also increase per meter). The jacks themselves also have capacitance. The same sorts of considerations apply when connecting hifi components with RCA leads.


    Treble response will have a resonance peak at the roll off frequency of the filter (rolloff frequency in Hz will be 1/2πRC) and will decrease after that at ~ 12 dB per octave. Here's some graphs and a couple of links on this stuff:


    [Blocked Image: http://www.shootoutguitarcable…tar-cable-equilibrium.jpg]


    [Blocked Image: http://zerocapcable.com/wordpr…ds/2015/11/cablecap51.gif]


    http://zerocapcable.com/?page_id=209


    http://www.shootoutguitarcable…e-resonant-frequency.html