I too have a real problem with Kemper technical showing no interest in this problem. See my post about turning the LFC function OFF to fix the popping sound. It works for me and I can set all amp and effects settings to extreme values without a single pop. I need others to test this out, so please try it and report back. Thanks,
Mark
Ok thanks for trying the LFC. Sorry to hear it didn't make a difference in your case. I presume you don't have any solution yet? It's very frustrating to have these issues which should not happen on a unit of this price. So far I have not had any ideas to try from Kemper technical support. They are unable to reproduce it and I wonder whether they are taking this seriously.
That's weird. I have no trouble in reproducing it at this end. I've also had this problem since 7.2.0 and I was hoping that upgrading would cure this, but apparently not! Starting to wonder if my KPA has a hardware fault? But it seems so unlikely because so much of the clever stuff is done in software and I would imagine that the LFC feature is also done in software too. I'm really struggling to know what to do next. Obviously I could simply just leave the LFC off, but I'm not happy knowing that there is a problem with my KPA.
I would be grateful if a few others could do this test and report back just to confirm. Any other suggestions welcome. thanks guys.
Rig volume and about a thousand other settings have been checked over many days. The red light goes on when the pop occurs, but it is the pop that is causing that to happen and not the other way round. The output is not clipping (at least not at the analogue end anyway) as I have inspected the waveform and there is some headroom available before clipping. Believe me this fault is related to LFC. Turn it off and the fault goes completely. Try to reproduce it from my instructions.
After listening to your audio recording, it sounds like you and I have a similar issue (see my post about LFC pops). I have spent days trying to diagnose this and whilst the problem seems to be only on certain profiles, I have found that I can tweak some of the clean factory profiles to exhibit this problem. The solution which fixes it every time for me is to go to page 8 in the "System" menu and tick the "LFC Off" box.
I already sent a backup and a couple of sound files to Kemper, but they say they can't reproduce it. I've tried everything I can think of - reloading the firmware; various reset methods including factory reset and initialisation of flash memory - all make no difference. The ONLY thing that completely cures it is switching off the LFC. Try it and see if it works for you too and let me know.
I wonder if any of you guys can also reproduce this bug.
I get a loud popping sound when I play the strings hard on certain clean sounds. After days and days spent on a process of elimination, I can eliminate the fault by turning the LFC off! Yes I know that the LFC was supposed to improve the bass response, but on my KPA Rack running public beta 2.7.3 firmware, I can reproduce the fault easily. Ticking the LFC Off box cures the problem instantly.
Here's how you can test it:
1) Load up the following factory profile: "Vab Clean" or "S.Mehl 50 Clean"
2) At the bottom of the main rig page, adjust the EQ as follows: Bass=0, Middle=0, Treble=+3.2, Presence=+3.2
3) Press / hold the Stomp A button to view the compressor settings. Set as follows: Intensity=5, Attack=0, Squash=0, Mix=100% Volume=0. Make sure the compressor is turned on.
4) Press the System button and cursor to page 8. Make sure that LFC Off is NOT ticked.) Now plug in a guitar and play the strings really hard. Really dig in. The fault does not happen when the strings are played softly. If you can't reproduce this, try a guitar with hotter pickups. I've tried two guitars, and it happens on both and I don't think that they are particularly hot. My input sens settings are both at 0.
5) If you hear the popping sound, go back to settings and tick the LFC Off box to turn it off. Now try again. The sound will be perfect. No pops at all.
Hopefully someone else will try this and let me know if they got the same problem or not? I sent Kemper some files to try, but they reckon that they can't reproduce the fault. I have tried reloading the firmware, doing 3 different types of restore including wiping the flash memory. Nothing I do fixes the problem other than leaving the LFC permanenty turned off. 
