XLR main out louder than TS main out

  • Hi! I've connected kemper to mixer console via xlr cables and input sound was very loud (main out set to -12db). Also i found the sound little brighter. when i changed connection to Ts cables level of input was softer and the sound darker. is there any difference between this outputs?

  • TS cables act as an RC filter - they low pass the signal, just like a guitar lead plugged into an amp, pedal or interface. The longer the cable and the higher the capacitance per meter the cable has, the more the treble roll off. ( roll off freqency is 1/2 pi RC where C is the cable capacitance and R is the input impedance).


    Assuming the signal has the same amplitude to start with, XLR balanced lines are louder than TS lines because they use a noise cancelling differential design which makes them suited to long cable runs (low noise, low impedance). This design sums two copies of the signal together at the receiving end (one copy of the signal runs phase inverted in the cable) giving both noise cancelling AND a significant boost in output level once they are summed.

  • TS cables act as an RC filter - they low pass the signal, just like a guitar lead plugged into an amp, pedal or interface. The longer the cable and the higher the capacitance per meter the cable has, the more the treble roll off. ( roll off freqency is 1/2 pi RC where C is the cable capacitance and R is the input impedance).


    Not really. With a high impedance source, like a passive pickup, cable capacitance will create a low pass filter...but that's not the case in this scenario.


    The differences the OP heard is likely either lack of level matching, or the mic preamp colouring the signal.

  • Not really. With a high impedance source, like a passive pickup, cable capacitance will create a low pass filter...but that's not the case in this scenario.


    The differences the OP heard is likely either lack of level matching, or the mic preamp colouring the signal.

    The R in that equation is the input impedance of what you are plugging the TS lead into, as I understand it. What do you think the output and input impedances are if you are running out the KPAs TS output into a mixer or amplifier?

  • The R in that equation is the input impedance of what you are plugging the TS lead into, as I understand it. What do you think the output and input impedances are if you are running out the KPAs TS output into a mixer or amplifier?


    600 -> 10k maybe? It's too low for capacitance to be of concern. A passive guitar -> amp would be around 5k -> 1M.


    R = source impedance in your calculation. You have to put brackets on it, btw 8) 1/(2pi x Zout x Capacitance)

  • As others have said XLR is Balanced TS is Unbalanced so XLR is 6db louder.


    However, the most likely cause of a significant difference in perceived volume and tone is the mic preamps on the desk being overloaded by the XLR. Many desks with combi inputs automatically engage the mic preamp when and XLR cable is connected. This is not desirable when you are sending a line level (not mic level) signal.

  • TS cables act as an RC filter - they low pass the signal, just like a guitar lead plugged into an amp, pedal or interface. The longer the cable and the higher the capacitance per meter the cable has, the more the treble roll off. ( roll off freqency is 1/2 pi RC where C is the cable capacitance and R is the input impedance).


    Assuming the signal has the same amplitude to start with, XLR balanced lines are louder than TS lines because they use a noise cancelling differential design which makes them suited to long cable runs (low noise, low impedance). This design sums two copies of the signal together at the receiving end (one copy of the signal runs phase inverted in the cable) giving both noise cancelling AND a significant boost in output level once they are summed.

    You are correct that longer cables introduce more capacitive loading but are failing to account for the *source* impedance of whatever drives that cable. When the source impedance is relatively high (e.g. guitar pickup) the loading effect will definitely be in evidence. But when driven from a source with low internal impedance, such as any of the Kemper outputs, it is negligible.


    The comment about balanced line behavior is on point, though. Adding two signals 180-degrees out of phase amounts to a 6 db boost, which is quite obvious.

  • Or just 6db louder = brighter (Fletcher Munson and all that)

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