Unknown USB Device (device descriptor Request Failed). KPA to Windows 10 PC

  • I have submitted a ticket to Kemper on this already. In the meantime I wanted to see if anyone could suggest a fix for this.


    The story so far, I've had the KPA power head since 2013. Over the years I have had no issues connecting the KPA to the computer. A few years ago due to health issues I boxed the KPA up and put it in the closet where it sat for three years. I recently started using a newly legalized medication with amazing results. I decided it was time to break out the KPA again and updated everything (os, rm, windows 10, and any hardware you can update on the pc (bios chipset etc.). I had never had the KPA connected to this particular pc as I'd only purchased it within the last year. I connected the KPA to the PC and got the unrecognized device prompt . I looked in device manager and saw the "Unknown USB Device (device descriptor Request Failed)" error on the connection.


    In the following days I have tried 6 different usb a-b cables (5 that were brand new). I have taken my KPA back to OS 1.8, upgraded it to OS 7.3.2 and then to OS 7.4.1. Uninstalled RM 3.0.131 and reinstalled it countless times. I have tried connecting the KPA another PC and it doesn't even recognize that a USB device was plugged in (no sound indications, no popups and nothing in the device manager). I tried connecting the KPA to a laptop and it behaved exactly as the second PC did. I connected the KPA to yet another laptop and got the same unknown usb device error I originally got the my 1st PC. Also both PCs and both laptops had RM 3.0.131 freshly installed on them.


    I've tried using the useless windows Hardware and Devices troubleshooter. I have uninstalled/reinstalled and attempted to update the drivers of every possible usb listing in device manager several times. I disabled the USB Selective Suspend Settings. I've been into the registry to attempt a suggested fix. Nothing has worked. One thing I have noticed is that the unknown usb device error appears when I hook up the USB whether the KPA is powered on or not. Any ideas? 8|


    kpA

  • I have a similar story:

    The connection between my profiler and Rig Manager on both a Win 10 computer and a Win 7 audio computer built by Sweetwater just stopped one day over two years ago when it was still under warranty. I reinstalled all the updates available at the time on both the profiler and RM. I tried new USB chords but nothing fixed the problem. I got frustrated with it and put it away for a few months. When I started back with it, I finally called Kemper support after going through the same steps as before. The tech said it probably was a windows 10 from win 7 upgrade that caused my computer to stop communicating with Rig Manager. He said if I couldn't get it to working, I could send it in and they would fix it.

    I won't go into what a procrastinator I am, but here we are, 10/18/20. The Kemper Profiler still works like a jewell. Great sounds with the rigs that come in it. It just can't communicate with Rig Manager. The Toast ME editor works fine with the midi to USB adapter by the way.


    Now that I'm determined to get this resolved, I've been researching for the last few days and found a reference to this problem on a Kemper-Cakewalk forum. One poster mentioned that Rig Manager should show up in "Sound, video and game controllers" in Device Manager. It's not there on either of the two computers I've used with the Kemper. I'm pretty sure they used to be there when it was working. I have gone through many of the steps you listed, installing the two newest updates for the profiler and DM. I was just about to start trying to manually install drivers on the Win 10 but I can see from your experience that that probably isn't going to help.

    Worse case, it could be an issue with the Profiler USB type B port on the back of the profiler. I'm probably about to send mine off to British Audio in Nashville, Tenn. Yesterday, a tech there told me that they have replaced the entire circuit board that includes the USB port, but he had never heard of an actual problem with the USB port. They have replaced circuit boards under warranty for other issues and that Kemper just sends them the entire circuit board. It's got to be pretty rare for a USB port to just fail, unless we're putting great stress on the chord or being rough with it. I don't know about you, but mine was on a table and was clear of obstructions and hadn't moved for over a year when it just stopped communicating.

    It could also be a software issue that only a handful of people have had. I've spoken to people at Sweetwater and at Kemper and none of them had heard of this problem. I would love to get mine fixed without having to send it off considering it's now out of warranty. That's my fault. But, as a plus, since Sweetwater pointed me to British Audio ( an official warranty repair center for Kemper), it turns out they have a couple of pretty neat upgrades for Kemper Profilers, so if I have to send it to them, I'm going to get the power amp upgrade.

    Good luck with getting your problem resolved. Kempers' are great by themselves but they're so much better when you have access to Rig Manager and are easier to update.

  • Waking up an old thread here.

    I've got the same problems as described above. I purchased my toaster in 2016. In the beginning I got it to work for short periods of time. But just sometimes. And then it would freeze. I don't remeber now what I did back then the times it worked. Since then I've been mostly using it with my preferred rigs and performances live. In my home studio I've just been using the same sounds pretty much.


    But lately I really been needing the Rig Manager functionality more and more since I'm in a band working on a new album. Sometimes the Kemper shows up in Rig Manager but it wont respond to anything I do on screen. And I often got the unknown device message in device manager.

    I have been in contact with Kemper support and sent the requested log files. But all I've got as a reply is that I have an unstable USB setup and that the problem is coming from my PC and not from the Kemper. I have also tried several PCs, cables, USB ports. All the tweaks I have found on different forums. Nothing helps!! I am getting really frustrated with this! No other piece of hardware what so ever is failing in my current setup. Just the Kemper. This little piece of incredible technology. Why is that? All logic is pointing towards the Kemper.

    I mean, I can go to whatever store and buy whatever piece of equipment and plug it in tom my PC. And it just works!!

    But not the Kemper. How can that be the PCs fault? Help me understand! Please!


    Is there anyone out there with some kind of idea why this happen to some of us?

    Every tip would be appreciated.

  • Eventually, the USB receptacle with fail from repeated attempts to insert and unplug USB cables. It gets worn out and the contact points inside get misaligned dropping the connection. Choices are then; either get a new case with new USB receptacles, or install a new USB card in the PC slot and add a USB hub or extension cable to the front.

    Larry Mar @ Lonegun Studios. Neither one famous yet.

  • Ditto on all points, and count me in for wanting to know why this is happening and how to remedy it! I've sent in my support request as well, and it's hard to imagine that this issue is limited to only a handful of Kemper users, yanno? Surely someone has figured out a fix or workaround by now.

  • Our engineering is looking into this. However, it's not as obvious as you might think. I'm using Windows 10 64 myself and it works flawlessly with current Rig Manager 3.2.57 and OS 8.6.2.

  • I actually went ahead and bought a brand new rack version Kemper for my home studio. When I plugged this machine into the same PC and the same setup where the old machine failed, it just worked straight away.


    I had some correspondence with the Kemper support. In the beginning I got an answer back that there would be something wrong with my PC setup and not the Kemper. After I bought the new machine and it worked I wrote again and explained that a new machine is working perfectly fine on the same PC setup. The reply then was that I would have to send in my old unit for repair and that it was liable for a cost since it's out of warranty. I've been waiting for a good time now to send it over since I'm using both units frequently.


    What bugs me is that back in the day when rig manager came out and I tried to get it to work I just assumed that the software needed updating. A couple of versions later I got tired of it and left the problem behind me. That's why it's been taking such a long time for me to get this sorted out. Back then I could never have imagined that there is a hardware problem behind it. But obviously there is a number of machines that have a faulty USB circuit in them. I mean if this was a car with a hardware problem you would get a notice that you need to return it to get it fixed (for free). In my opinion it would be nice if Kemper recognized the problem and took care of it. It's not easy as a consumer to know when it's a hardware based problem and not a software one, right? Or am I wrong?

  • Rig Manager is used since many years by thousands of clients. Connection issues can have many different reasons (mismatch of versions, USB cable, USB hub, PC setup and driver, Rig Manager installation,...). Sometimes it's a combination of those. Defective PROFILER hardware is only a very small fraction of it and even that is multi-facetted (a single chip, a socket perhaps with twisted contacts, a board,...). There has been no class-issue

    suggesting a general recall of hardware like car manufacturers sometimes experience it. USB and other sockets are part of the final tests performed before any unit leaves the factory. The USB connection of your PROFILER must have worked, when this unit left KEMPER ground.


    I guess, the PROFILER in question is of 2016. We offer 36 months manufacturer warranty covering such issues. The only support ticket I can find under your e-mail is of December 2020. It appears, you never raised this issue within the years of warranty. Or can you provide any reference?

  • Of course I should have raised a support ticket for this issue earlier on. So the delay and the warranty time running out is my bad. No argues there. The frustration comes from the fact that it actually is a hardware problem AND that it never worked properly. So if the PROFILER worked before it left the factory it stopped working before I opened the box. I could not have imagined this to be a hardware issue, so I set up my sounds over a period of time and started gigging with it. Being certain that it must have been a software/driver issue I just didn't bother until I needed the functionality again. And then the warranty time had runned out.


    I'm not trying to create a fuzz here (pun intended). If there is no such thing as a bad batch of USB circuits then I have myself to blame. And maybe the car reference was a bit misplaced to :-). I mean this isn't about a faulty airbag. I love the Kemper stuff and think it's awsome. Now I'm working around the problem since I bought a new unit. I set up my patches in that one and transfer it with a USB stick to the old one. Works good so far. Maybe I'll send down the old one to fix it anyways. We'll see.


    Rock on!

  • Ok, to be honest I don't see the "batch".


    This thread started more than one year ago with "Unknown USB Device" errors in Windows. regardless if the PROFILER is switched on or off, which means there must be a physical connection.

    riffjunky decribes another scenario where the PROFILER doesn't even show up in Device Manager, which might be a real hardware connection problem.

    BayouTexan refers to worn out USB connectors. Perhaps an user damaged it himself!?

    RedGtrRocker refers to "this issue", but there were already three different ones. Perhaps he had even a forth one!?

    These issues only look similar on a surface level. And now relate this to five years of production....

  • Please check out OS 8.6.6 which should solve the PC/MAC connection issues few users are experiencing for earlier 8.6 revisions as well as some other issues.


    This OS is currently available as public beta. Rig Manager will recommend it, if "Beta" is selected in its Preferences. It can also be downloaded for USB flash drive upgrade here:


    Download Operating System Beta Versions

  • Same issue here "Unknown USB Device (device descriptor Request Failed)"

    I'm on OS 8.6.6.32765, RM 3.2.65.17265, and Windows 11 with a kemper stage.


    The kemper USB does not connect to my own laptop. However, I just tried on my work laptop which did not previously have the rig manager, and everything seems to be working on the work laptop as it should. I can import my rigs from the kemper, etc.

  • I'm using Widnows 11 myself and it works seemlessly from the beginning.


    As far as I know, there can be an issue, if you perform an upgrade from Windows 10 to Windows 11 and havn't used any driver for more than six months before. This can also happen to PROFILER and Rig Manager. In that case a driver repair or reinstallation of Rig MAnager should do the job.