Funny "distortion" or clipping in Kemper Rack ...

  • I searched the forum and didn't really find anything on this. I've got a Kemper Rack (unpowered), current OS, current Rig Manager version, running into a Fryette PowerStation and then to a 2x12 with Celestion F12-X200's.


    When I play a "crunchy" profile (like a MBritt EL84 crunch) i get this bit of distortion that sound somewhat "digital" or clipping (not in the good way). My input is not "red," and messed about with Clean Sense and Distortion Sense to no avail. I'm not running anything in the loop, no external effects pedals. Have two Mission pedals (1 wah, 1 morphing).


    Here's a clip from tonight -- the sound I'm talking about is just "behind" the main tone. Hoping for any thoughts. It does this equally (as far as I can hear) regardless of guitar, pickups, etc. On pure clean rigs I don't hear it, and if it's on the full distortion rigs (Marshall 800, '69 50w, etc.) I can't hear it over the main distortion.


    I'd appreciate any thoughts. FWIW, I just watched a ToneJunkie YouTube clip on using the Clean and Distortion Sense, and it seemed like HW may be having that same sound (he apparently didn't mind it or didn't hear it).


    Edited to add: it is most prominent on the G string from open up to maybe D or so ... in the clip below, to my ears, this "clipping" diminishes when I'm on the B string at the 7-9 frets. This made me think EQ, but adjusting the BMT and Presence controls on the Rig didn't seem to affect this "clipping" tone.


    https://www.dropbox.com/s/q3zy…0Clipping%20Demo.mp3?dl=0

  • 2 cents from here: Did you guys try to put a High/Low-cut in the signal chain, preferrable after the stack, e.g. in slot X? After some time with the Kemper enjoying many profiles I found myself to put this into the X slot almost all the time, actually with different values especially on the high cut side. And I think Kemper's approach to make High/Low-cut available in the Output section now is a hint how much it is needed with some profiles.


    Fingers crossed you'll get it fixed in whatever way as I can imagine it is really distracting for the ear...

  • I think it's the guitar.


    That "funky" (not in a good way) resonant vibration is something I've encountered with a couple of guitars in the past. I wasn't able to do anything about it, unfortunately. In my case it usually manifested on the thicker strings and from perhaps the 10th fret upwards. In your case the particular resonant vibrations produced by your G string may be the culprit. The overdrive range that brings it to the fore is likely adding harmonics which make it easier-to-hear.


    Could it be that the Kemper is simply revealing a flaw that wasn't apparent before when using your previous gear? Just throwing this out there.

  • My les Paul does that, and I think it’s because of the TOM bridge. It seems to be some sort of buzz «behind» the b string, both literally and figuratively... I can even hear it when I play it unplugged. 😊

  • Yes, I just replaced the cheap TOM of a new Gretsch with a Gotoh, it had the same rattle. It was the wire that is supposed to hold the screws in place, running perpendicular to the strings. Superglue or nail polish is a temporary fix...

  • So ran straight in to the Kemper Rack - unplugged the Remote - not outboard effects, no wireless, just guitar-->cable-->Kemper. That "distortion" is still there. Tried every electric I own, no difference. Tried high pass and low pass filters. Odd -- not a deal breaker since I do live work with this rig, and I imagine few others would hear it unless I pointed it out - but it's definitely there. But if I were recording this would be a big deal.

  • So I have done quite a bot of experimenting. I’m using the Powerhead, remote and Kemper Kab.

    I find that most profiles have a quite pronounced digital clipping distortion unless I roll off the guitar volume. It does not happen on the ToneJunkie Purple Plexi or one of my own but pretty much everything else will do it. Happens on SIngle coils but also on humbuckers. I’m sure it didn’t always do this so maybe some setting I have changed. Anyone any ideas?

    Cheers

  • There seems to be an increasing number of posts about something similar to this. I wonder if its related to the OS update.

    I'm not running a super recent software version. Don't have my Kemper near me, atm, to check the version, but it's definitely not a beta version. It does seem like there are a lot more of these issues showing up. The scary thing is, after I did a full wipe and reload of the backup, it was fine for a while. It didn't start until the Kemper had been off for a few days. If this happened at a gig (not that many of those are happening now), that would be a huge problem.


    Has anyone else done a wipe/reload and had the issue reappear?

  • Hi,

    I noticed a harsh noise in all of my profiles too, must have happened since the latest update.

    Don´t know for shure if the update is the cause, just chronological order.

    I uploaded some recordings of a TopJimi DCAC Malcolm profile that sounds just wrong and rather horrible, which is not typical of these profiles.

    I DO clip the input if I really dig in, but a) that never was a problem before, and b) no setting of clean and distortion sense makes it go away.
    Strange resonance, bad sounding distortion. Sounds broken.

    I´m not shure if it´s getting worse, or if I am getting more tuned in to the problem. Getting worse would lead to a broken part moving out of spec.

    System reset did not help.

    Sounds are here: https://www.dropbox.com/sh/loy…KGvL5ZXrTwJGCdtwRCxa?dl=0

    It´s not as evident on lower output PUs, but still there.


    I´m on Version 7.4.1.171821 on a rack profiler.

    It´s not: The cable, the soundcard, the guitar, I checked.

  • Turned the volume pedal off in the Rig settings, to no effect. Have an FCB1010, but I don´t use it here at home; it´s connected but turned off.

    Meanwhile every rig is unusable, sounds really bad. Every distorted profile is very nasal, overly and digitally distorted.

    Like some kind of input or output filter is running away.

    Calling customer service tomorrow.