Kemper Power Head random volume loss

    Hi


    My Kemper Power Head has developed a really worrying issue over the 6 weeks.


    It randomly loses nearly all volume via the powered speaker output. It is a global problem and does not seem related to any profile. When it occurs, virtually all volume disappears leaving a tiny amount of volume. The line level 'monitor out' is UNAFFECTED when this happens - meaning there is no corresponding volume loss.


    If you turn it up really high the volume does increase buts sounds wobbly and distorted. The dipslay and other controls are all normal. When you turn it off, it usual happy goodbye pop is replaced by a weak fizz. On one occasion it happened as soon as I powered it on ... again with a very sickly fizz sound.


    I am using a Kemper remote but no volume pedal or any morphing.


    Rebooting *nearly* always fixes it - until it goes wrong again ... which is one in every three sessions. I have a gig coming up and am really worried.


    I'm running the latest OS 5.5.2. I had been running the spring reverb beta - Kemper told me to back out to a full version to see if that helps. Unfortunately it makes no difference.


    Has anyone else seen this problem recently or even better have a solution?


    Same issue raised before:


    random loss of volume

    Sudden Volume (Monitor Out) Issue

    Sudden Output Level Drop - Main Output

    Power amp volume drops


    Best wishes,


    Simon

    Edited 4 times, last by mirkin: Found some cross references ().

    After searching the forum, it seems that this issue has raised its head many times. Many commentators think it is related to the linking of the various outputs to the master volume control (using the options on the output settings pages).


    So I have un-linked ALL outputs from the master volume to see if this helps. Will send an update

    Unfortunately the problem occurred again then ten minute later righted itself. The logical conclusion is that it must be a hardware controller issue. Such a downer as this means the amp will have to go back to Germany

    Kemper support asked me to see if the volume was down on the line level 'monitor out' jack when the volume collapses from the power amp speaker output. Luckily the problem occurred and I can now confirm that the line level 'monitor out' was NOT effected ie it was at a normal level whilst all the volume had dropped from the power amp speaker output.

    Same thing just started happening on my Kemper yesterday too and I am still experiencing this issue of sudden volume drop and fizz ?. Going to contact KPA support.

    Okay I once had an issue like this ... However I had the KPA configured to use one of the 1/4 inch controller ports to connect a volume pedal.

    When the volume drop happened I took the 1/4 inch jack and worked it in and out several times and things came back to life. My hypothesis is that the KPA's jack or the cords jack might have had some corrosion and made one of the connections to the KPA JACK float intermittently which can cause strange volume changes or even total loss. So its a little like snake oil but maybe even if your not using them that somewhere along the way the KPA might have got a little confused , scanned them and jumped to service the volume by mistake. So for the heck of it work a 1/4 inch jack in and out about 6 times on each controller jack and then fire up the KPA and see if this helps...

    If the problem continues and your not actually using the controller jacks for anything you could look to see if CONTROL 1 or CONTROL 2 looks to be assigned or better yet just simply perform a [ SYSTEM ] ( INIT GLOBAL ) Maybe there some boot control registers that have corrupted data that is causing the phenomena. Hope this helps ....

    Just from your description I think a Global Init maybe the magic bullet for this condition. But it wont hurt to give the jacks a slight work out as well.

    If accidental volume changes are caused by an expression pedal and its cable connection (TRS), this can easily be verified looking at the pedal controller bars on page Pedal Links in System Settings. If your pedal is configured as Volume Pedal you check the bar "Volume". And if your pedal is configured as Wah Pedal and the option WahPedal to Volume is activated, you check the bars for Wah and Volume and can monitor, if that works as expected.


    If those bars don't reach minimum or maximum, you should recalibrate on the related page PEDAL n. If the bar doesn't follow you pedal moves, your pedal or your cable might be defective or not completely plugged in. If your expression pedal has a pot to limit its range, make sure, that this pot is set to maximum range. Perhaps you have limited the range so much, that the pedal is practically dysfunctional.


    If just an open cable (TRS cable without expression pedal connected) is plugged into one of the PEDAL sockets, the assigned controller bars fluctuate. That is caused by the automatic recalibration the PROFILER performs and is normal.

    Thanks everyone for the responses. I have tested with multiple cables and speakers and it still happens. As I stated before I don't use any volume or expression pedal.


    In any case the problem has progressed. It started happening all the time. Then, a week ago, the power amp went completely belly up. So it was a hardware issue all along. Kemper support agree with this diagnosis. A complete pain in the arse.

    I have the same issue, and the amp is back with Kemper. At the moment they can't re-produce the problem. It was happening to me during gigs after about the 5th song and I had the change to using the Monitor Out to an active speaker (quite stressful during a gig!)


    Will report back when they find the problem.

    Regarding the issue on the video, I would check

    - cables and guitar

    - test both inputs: Front INPUT and ALTERNATIVE INPUT with Input Source set accordingly

    - test MONITOR OUTPUT with a powered speaker or mixing desk or just plugging in headphones (signal on one side only)

    If all these components are functional and just the SPEAKER OUTPUT shows the issue, we have to conclude a defective power amp.

    I have recently noticed this same issue.

    In my case, I've successfully isolated it to being an issue with Kemper's Volume Pedal technology.

    As long as I don't touch my Volume Pedal, everything works as expected and volumes between patches and system are maintained correctly.

    However, as soon as I touch the Volume Pedal, everything gets messed up.

    Also, as soon as I unplug the Volume Pedal, the issue is immediately resolved.

    As a temporary workaround, I've configured my patches to just have a volume increase when I click a the currently activated switch a second time.

    This is definitely an unacceptable issue for any professional environment and I really need to get this resolved.

    Any feedback is greatly appreciated.

    I'm also going to follow up with Tech Support and will update this post if I learn anything useful.


    Current OS - 8.6.6.32765

    OS Build Date - Oct 26 2021 16:53:29

    DSP Date - Sep 17 2021 15:24


    I'm using the Kemper Profiler head with built in 600w amp.

    I always run directly to Front-Of-House in stereo for all gigs and never use the power amp.

    There is no such issue with the "KEMPER Volume Pedal technology". I guess, you can imagine how many people are using a PROFILER with an expression pedal controlling volume since up to ten years and what would happen, if such basic functionality wouldn't work reliably.


    Check your setup and settings. Is your expression pedal and cable ok? Perhaps Volume Pedal Range is screwed and Volume Pedal is locked....

    scott4est We are still watign for a concrete descriptions and example (PROFILER backup) what is meant by "However, as soon as I touch the Volume Pedal, everything gets messed up."


    I'm reading that you are storing Volume Pedal Range at different levels in your Rigs, sometimes below and sometimes above 0. That makes a major difference as it transforms the pedal between a normal volume pedal (n% to 100%) and a booster pedal (100% to m%). Perhaps that intended behavior feels as "messed up".

    ¨   Volume Pedal Range

    This is a bipolar parameter. In the middle position, the Volume Pedal has no effect. When you set the Range more to the left, you determine the minimum volume at heel-position, while the maximum volume at toe-position stays the same. At the minimum position, the pedal performs the swell from zero level, just as you would expect from an analog volume pedal. As you turn “Volume Pedal Range” towards the right half, the Volume Pedal turns from an attenuation pedal into a booster pedal. Now, the heel stays at standard volume, and the toe-swell will give you a volume or gain boost. The maximum boost, at the top position of “Volume Pedal Range”, is +24 dB.