Clean profiles have static and distortion

    Quote from ckemper

    If the input led stays green or yellow (or a bit red), you will get no early distortion in clean rigs.

    Yes, that's the strange thing. I just double checked that the Input and Output leds are not clipping. In fact, there is no single point in my whole audio chain where the signal is clipping (I revised everything, from the Interface to the FRFR monitors...). Also tried lowering even more the Clean Sens parameter so that input led stays always at green and would never go not even into yellow, but the crackling was still appearing...

    I've seen several variations around this crackling theme. Broken pickups, bad wiring, or external electromagnetic noise may be more prevalent with some guitars, but I don't believe that is the full explanation. I've got a Les Paul with burstbuckers (2+3) that produce crackle on quite a few clean profiles, but there's none of that audible crackle through an ordinary amplifies no matter how low or high I crank the amp. Pickups, wiring, jack and components in this guitar are all brand new and it has got the best possible EM-shielding. I've isolated the crackle from the KPA with a signal analyser and compared to the output from the guitar. The analyser doesn't see anything coming from the guitar that would be an obvious source for the noise. Other guitars produce no crackle on the KPA with the same rigs. I suspect this may have something to do with how the KPA's input handles the impedance "seen" from the guitar, and that some values may be problematic.


    Recently there has also been quite loud crackling that appear for 3-5 seconds after switching to certain profiles. Then the KPA "settles down" and sounds just fine. For me it happens mostly with clean profiles, but others have reported problems with distorted rigs too. This problem has been verified by the support-team and registered as ticket #KA00084252.

    I've played one guitar for 20 years and not heard the crackle in tube amps, POD, etc., only after plugging it in to KPA. Impedance range issue sounds like a reasonable guess if kemper has confirmed it with some guitars.

    Quote from harmonic

    I've played one guitar for 20 years and not heard the crackle in tube amps, POD, etc., only after plugging it in to KPA. Impedance range issue sounds like a reasonable guess if kemper has confirmed it with some guitars.

    Yes, CK said they replicated the issue with some of their guitars. He also said that with those guitars making the crackle, you could still hear the noise when pluging directly into the DAW and kranking up High-end EQ.
    Though I can only hear it when I plug the guitar through KPA, the signal is crystal clear when directly into DAW. Also the crackling seems to disappear when disabling the Amp section of the Stack.
    Let's see if they can shed some more light in this issue! :thumbup:

    I experience the crackling, too. It happens with all my guitars, and it doesn't matter if I use single coils or humbuckers. It happens with both clean and crunch rigs. It's very apparent if I use Rig Manager to scroll through various rigs. Some rigs crackle more than others, and sometimes a rig crackles a lot at first, then settles down.


    However, here's an interesting observation: it only happens when I monitor the KPA through my audio interface via S/PDIF (KPA is master, and levels are set properly). I don't hear the crackling if I monitor via headphones connected directly to the KPA.


    I'll experiment more with various connections and try to isolate the problem. I'm using OS 2.5, but will roll back to an earlier OS to see if the issue persists.

    Quote from MassGuitar

    I experience the crackling, too. It happens with all my guitars, and it doesn't matter if I use single coils or humbuckers. It happens with both clean and crunch rigs. It's very apparent if I use Rig Manager to scroll through various rigs. Some rigs crackle more than others, and sometimes a rig crackles a lot at first, then settles down.


    However, here's an interesting observation: it only happens when I monitor the KPA through my audio interface via S/PDIF (KPA is master, and levels are set properly). I don't hear the crackling if I monitor via headphones connected directly to the KPA.


    I'll experiment more with various connections and try to isolate the problem. I'm using OS 2.5, but will roll back to an earlier OS to see if the issue persists.



    Interesting!


    I'll need to see if mine is the same when I get to a rig that has the crackling when switching to it. I have experienced the same, but can't remember if it was only via interface. I use SPDIF too. It seems to be prevalent on some profiles especially.

    Mine crackles at profiler start up for first second or two of sound. Then goes away. Main outs (XLR) to powered studio monitors. Does it with and without guitar plugged in. Output LED goes red during the crackling. Definitleyin the KPA as no guitar connected and evidence in output LED.


    Also crackles when scrolling through rigs, both clean and distorted.


    I'm on OS 2.5 and don't recall hearing this before I updated. I will roll back and see if it goes away with old OS when I get a chance. I'm highly suspicious that in order to speed things up in OS 2.5, that buffers are not being zeroed out properly and results in garbage sound for a second or so. Rolling back may add some credibility to this.

    Quote from heldal

    I've isolated the crackle from the KPA with a signal analyser and compared to the output from the guitar. The analyser doesn't see anything coming from the guitar that would be an obvious source for the noise. Other guitars produce no crackle on the KPA with the same rigs. I suspect this may have something to do with how the KPA's input handles the impedance "seen" from the guitar, and that some values may be problematic.


    You confirm exactly what we have observed. It happens with several guitars, while other guitars don't do it. We were able to retrieve the same noise with just using an audio interface, as mentioned.
    You might agree, that if there was such a "impedance problem", it would not be specific for a fraction of rigs only, since any impedance issures play in the analog domain, while rigs exist in the digital domain, and do not communicate with the impedances.


    Quote from heldal

    Recently there has also been quite loud crackling that appear for 3-5 seconds after switching to certain profiles. Then the KPA "settles down" and sounds just fine. For me it happens mostly with clean profiles, but others have reported problems with distorted rigs too. This problem has been verified by the support-team and registered as ticket #KA00084252.


    We will investigate this "short crackling".

    The hint to audio interfaces behaving the same is intriguing. Having to maximize the highs in order to hear the unwanted noise makes it a revealing experiment and nothing more tho.


    The problem remains tho: the Profiler reveals the noise under normal use, which makes those profiles useless. We need a solution anyway, and having to use a selection of guitars with the Profiler (provided that one owns guitars that don't exhibit this behaviour) is of course out of questions.


    Using a clean profile doesn't equate to cranking highs up. If the profile sounds like the real amp, then there are no excesses of any frequencies in the profile(r), are they?
    This might suggest that the solution might lie in how the Profiler handles high frequencies, either during the profiling process or during playback.


    Also, it would be interesting to investigate why and how guitars produce the noise. Sounds like a capacitor discharging...

    Quote from viabcroce

    The problem remains tho: the Profiler reveals the noise under normal use, which makes those profiles useless. We need a solution anyway, and having to use a selection of guitars with the Profiler (provided that one owns guitars that don't exhibit this behaviour) is of course out of questions.

    Totally agree !! I can hear the damn crackling in all my guitars and nearly all the clean profiles (though it's more evident in some rigs than in others) .
    Sure I'd like to see a solution on next firmwares.

    I've found a profile which seems to act in an opposite way as regards the issue.


    With 44-MKII Clean by And 44 (a clean profile), the crackling only appears on the low strings. It's not related to grounding or guitar setting.


    Note I wrote "on the low strings": while taking the same note on strings of gradually higher order (thinner) the issue fades away.
    This is meaningful because it appears to only happen on this profile ATM.


    And I can also confirm that the issue is located in the Amp section. I've progressively switched off all the other sections with no changes. Switching Amp off makes the issue disappear.


    The sonic spectrum of the crackling is mostly located around 2500 Hz (roughly checked by trying to eq it out).


    I'm afraid I can't record anything ATM, and have got only 1 guitar here; but HTH nevertheless.


    EDIT: I've probably caught the bug LOL.


    It's related to the Pick parameter: values different than 0 (both negative or positive) trigger the noise.
    For small displacements the issue is almost negligible. It does'n seem to grow linearly up to |5| tho, with an apparent maximum noise around about |3.5|. I apparently cannot notice a difference between positive or negative values as well.


    EDIT: Apparently, almost all the clean profiles suffer from this, even tho not all by the same amount. For example, 9 V BJL by M Wienstroer seems to be rather unaffected.
    Note: by "clean profiles" I also mean high-gain ones with the gain turned to 0. Tried with 44-Plexy SOLO by And44 cleaned down, and the results are the same.


    Really HTH: the Pick parameter in absolutely the one I use most with clean profiles
    :(

    Edited 2 times, last by viabcroce ().

    Quote from viabcroce

    And I can also confirm that the issue is located in the Amp section. I've progressively switched off all the other sections with no changes. Switching Amp off makes the issue disappear.

    Again agree with that 100%.



    Though, I also get the noise with the Pick parameter at <0.0>. If you listen carefully, you'll find the noise in all the clean rigs (unless you deactivate the Amp section ofc..)


    Another thing, I observed it to happen on the low strings too, but also in the high ones, yo only need to make a chord and there it will appear the cracklings.

    The problem with the pick parameter has been discussed before. I thought it was fixed, but looks like it persists.


    Question is, is it the pick parameter or the guitar? The idea that certain guitars don't work well with the Kemper seems horrific. Can everyone identify what pickups they're using when they get this problem?


    In that regard, at first glance, I don't seem to have this crackling sound with EMGs or Bill Lawrence pups. Can anyone identify certain characteristics of pickups that have this problem? Something with electronics? Is it some sort of magnetic thing? Something to do with electronics?


    This is a different issue, I also have cracklings on some profiles which reveal themselves on the highs. Getting noises with Pick set to 0 it's clearly something else, altho it might be related.
    Next time I come across a profile of the other kind I'll post it here :)


    nightlight: I'm having the issue with Bill Lawrence L400 (either of the two). Far from my other guitars ATM, will have access to them in September.

    Quote from viabcroce

    This is a different issue, I also have cracklings on some profiles which reveal themselves on the highs. Getting noises with Pick set to 0 it's clearly something else, altho it might be related.
    Next time I come across a profile of the other kind I'll post it here

    Okay, I though we were talking about the same kind of crackling. Althoug I never noticed any strange behaviour with the Pick parameter.




    About my pickups:
    - Seymour Duncan AHB-1 Blackouts (this girls have a HOT output)
    - Ibanez V87 and V77 (HB)


    They both generate the so called high-freq crackling on clean profiles. Also the crackling is present whether using HB mode or SingleCoil.


    I still want to try with a pair of EMGs that I have as spare parts. Though I thting I'll get the cracks too, as they have clean and hot output.

    I have the same issue as well, I even opened a support ticket and the kemper team reported back that they were able to reproduce it with just an audio interface with cranked highs, and that it is guitar specific.


    The thing is, as many others have stated, that NONE of the other digital devices I have worked with, or real amps for that matter, reveal this problem. Oh and I have tested it on all SEVEN of my guitars, three of them being in the 2000Euro range.


    I am REALLY hoping that a solution to the problem is found as the kemper is an otherwise amazing product, but as it stands now, the clean sounds (the way I like them) are pretty much unusable. :(