Unexpected loudness-cracks

    I want to use an electric and an acoustic guitar with the KPA (FW 2.8 whatever) alternately. The electric guitar at normal input and the acoustic on the return input, mono loop activated on Stomp A. This generally works well, but there are unexpected volume jumps when the rig is enabled with loop in A Stomp. Why is that? Does anyone have this problem and it can be solved? Are there better alternatives to use two guitars (eg A/B box)? Can someone give a good advice?

    Play it like you mean it.

    You'll lose the ability to cut the signal to the acoustic, but instead of putting it in a mono loop, use it like an Aux input (like when you feed an mp3 to the KPA for jamming, etc. There's a How To somewhere on the forum and probably on wimp.org). That way the acoustic won't go through the Cab part of the profile, so you'll retain all the highs without turning the Stack/Cab on and off, and it should also deal with any volume issues.


    Cheers,
    Sam

    The profiler has two inputs: the normal input on the front and the aux input on the back. You can switch between both via the input or the system menu (can't remember exactly atm). I hope I got everything right (language barrier?), but using the aux input has nothing to do with bypassing anything.


    sambrox: What is wimp.org? Or do you mean wikpa.org?

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

    Argh yes, stupid autocorrect!!!


    If you set the Alt Input up as an Aux, then you DO bypass the Cabs. Try it : use Alt Input to feed a mono loop set AFTER the Stack (in X or Mod). Engage and disengage the Cabs while playing. Hear a difference?


    Cheers,
    Sam


    Edit : I am of course referring to the Return input, NOT Alternative Input! Sorry! Alt just mirrors the front input.

    Shit/autocorrect happens, sambrox. :)


    A loop always "wastes" a slot. Maybe the switching between front and alt input works too?

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

    Probably, but then the acoustic will go through the Stack too. Might be what the OP requires, dunno. I find that my Acoustasonic Tele sounds best when the Stack is bypassed.


    Cheers,
    Sam

    Yeah, I get your point, but you can always store an acoustic-rig with switched off amp and cab! Maybe this way you have the additional advantage of the stack-EQ-section.

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

    True enough. The Parallel Path option can also give great results, using a compressor and maybe a touch of chorus in parallel and a nice, clean rig profile.


    Cheers,
    Sam

    Thank you for your great input!


    I have the cab in my acoustics - profile disabled as I prefer the direct sound.
    Stomp A is defined as the "input loop"
    Stomp B has a slight compressor
    Stomp C is an EQ
    The stack section is bypassed (except the EQ section on)
    In the effects section I sometimes use chorus, delay and reverb.


    For this reason, the AUX input is not optimal. I am controlling my KPA via MIDI (FCB 1010), so the manually switching of the input section is very awkward since this can not be switched via midi.
    As I said, basically my setup works well, it is just this unusual volume-cracks. Can this possibly be the compressor? (but should not be ...) When I disable the compressor, there are less cracks but unfortunately they do not disappear completely.

    Play it like you mean it.

    It should also be noted that the alternative input is noisier than the front input, as stated by CK himself. I think it's intended to be used for line level signals, if you have your KPA permanently set up in a patch bay in the studio. This might also be the cause of clicks and crackles. Does your acoustic exhibit the same behaviour when going into the front input?


    Cheers,
    Sam

    When I use my acoustic guitar with the front input, everything is normal and works fine. Maybe it´s indeed an impedance issue - if I plug in my electric guitar in the return input, the crackles are still there. Maybe it helps, if I use a DI-Box before the aux input to get the signal to a line-level?

    Play it like you mean it.

    Maybe this helps too (look at the impedance of the front input):


    Front Input: ¼ inch TS unbalanced, dynamic range >108dB, impedance 1 MegOhm
    Alternative Input: ¼ inch TRS balanced with ground lift, dynamic range =105dB
    Return: XLR balanced, ¼ inch balanced with ground lift, dynamic range =105dB

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