Kemper Stage - Gating/Distortion Issue

  • Acoustic guitar with LR Baggs Lyric pickup into Kemper Stage.


    About 9 months ago in the middle of a gig, the output became gated and distorted. It sounded like the 9 volt for my pickup was dying so we took a break and I dropped a new one in. It didn't fix the issue so I slapped a vocal mic in front of the guitar and continued on with the gig. The next morning I plugged everything in and it all sounded fine. I never figured it out and it never happened again until this past weekend. Except this time, the issue is still happening today so I've been troubleshooting...


    My pickup has a volume knob and no other controls. If the knob is all the way up (where I normally keep it) the signal into the Kemper is gated and distorted. I have to play hard for it to come through and when I do, it's distorted. If I turn the volume down on the guitar I eventually hit a sweet spot where everything sounds fine (except weaker than normal since the volume is lower). So it sounds like the Kemper is gating the signal - almost like an overload protection feature.


    The problem is that this never happened outside of these two instances and as I said, the first time it happened, it went away the next day without me changing anything. I've been using the same guitar (at full volume) and the Kemper Stage for several years almost every weekend.


    Additional information:

    • I've played with this setup having the pickup at full volume for years and it's sounded great, with no gating or distortion, until now.
    • I tested the guitar in other devices to rule out the issue being with the pickup rather than the Kemper. No issues in other amps/processors at full volume.
    • Noise Gate feature under the Input section is at 0.0 as are Clean and Distortion Sens.
    • This happens with any Rig loaded
    • This happens even with no stomp effects applied to the Rig
    • The master volume on the Kemper Stage has no effect on the issue
    • I've never had this issue with any other guitar (acoustic or electric)
    • I've compared the output signal level from my acoustic guitar with several of my electric guitars. The signal from the acoustic guitar is not any stronger than the signal from any of my other guitars.


    Thoughts?


    Thanks,

    Jon

  • Thanks Don and hubzim.


    I’m not sure how the issue would just happen out of nowhere after the battery has been in the guitar for months. And then continue after changing the battery. I’ve changed the battery twice in the past few days with no improvement.


    If I pick up a voltage meter, what exactly should I be looking for to know that the 9v or pickup is causing the issue? And then how would I go about fixing it?

  • hi nightstick

    before talking how to solve the issue you have to confirm whats happening


    from my point of view dons tip to first rule out the battery is absolutly correct, trying different new batterys should be adequate.

    please keep also in mind that the lyric power switch could cause trouble. i think you are using a guitarcable with mono plugs, so i think the plug into your guitar is also the power switch. the contact may be dirty so try to clean by moving the plug several times in out out.


    if the issue is permanent you can check dc voltage at guitar output:

    - get a voltmeter and switch to dc measurement

    - connect guitar to kemperand ensure the issue is there

    - disconnect the cable plug from kemper input and measure voltage between tip and sleeve, normally should be 0 volt


    please consider:

    - the issue described in the New Ibanez GSR200 Bass works with Helix but Not Kemper thread is not a kemper fault but from my point of view a design fault by ibanez

    - every electronic circuit can fail even satellites or nuclear power plants. when you search the lr baggs forum you can find several similar faults

    so wish you good luck ;)

    hubert

  • Hubert,


    As I mentioned in my original post, I've changed the 9 volt several times and still have the issue. The contact also seems to be fine because the guitar works perfectly fine in every other amp, mixer, and audio interface I own, regardless of where the volume knob is on the pickup.


    Regarding the issue described in the thread I reference, I'm referring to the most recent posts where they point out that the Kemper seems to shut down the signal if the voltage is too high. I guess you could call that a design fault by Ibanez and also a design fault by LR Baggs in this case if it's the same issue (which it really sounds like it is)... But either way, the Kemper seems to be the only device I can find that has a compatability issue with the guitar.


    You mentioned testing it with a voltage meter again but I'll re-ask my question - If I pick up a voltage meter, what exactly should I be looking for to know that the 9v or pickup is causing the issue? And then how would I go about fixing it?


    Thanks again.

  • hi jon,


    the ibanez issue is clearly a design fault because every instrument seems to show the behaviour


    with similar fault at lr baggs forum i tried to say that there is a possibility of a faulty circuit.

    when there is dc at the output you have a defective circuit.


    but first of all you have to proof. you can do it easy this way:


    if the issue is permanent you can check dc voltage at guitar output:

    - get a voltmeter and switch to dc measurement

    - connect guitar to kemperand ensure the issue is there

    - disconnect the cable plug from kemper input and measure voltage between tip and sleeve, normally should be 0 volt


    when you get dc voltage you have to repair the lr baggs

    when not...?

    cheers hubert

  • FYI. A 9v battery will cause a home smoke detector to start twerping low battery at 8.25 volts.

    The more you find what Kemper can do then the harder you try to find what it cannot do -- like make a good cup of Frappuccino.

  • hi jon


    i saw your comments on the Ibanez thread and your earlier comments on this one about the LR Baggs being an expensive system which shouldn’t be badly designed. Also the fact that there aren’t any mentions of such an issue on the Baggs forum. However, I think the main point about what Hubert is saying is that it may not be a design fault but rather an intermittent fault in the wiring of your particular instrument. It could be a dry solder joint or something else shorting a connection somewhere. As Hubert said, the first thing is to confirm for certain whether DC voltage leakage is occurring. A simple multi meter is the best way to check this. A multimeter is a great thing for any guitarist to have anyway as it can be used for testing cables, batteries etc. I would recommend buying one and keeping it in your gig bag anyway.

  • think the main point about what Hubert is saying is that it may not be a design fault but rather an intermittent fault in the wiring of your particular instrument. It could be a dry solder joint or something else shorting a connection somewhere.

    Again, if this is the case, then how is it that it only happens when plugged into the Kemper and not when plugged into any other processor, amp, mixer, etc/? It's not intermittent. I'm sitting here going back and forth right now. Plugged into the amp, everything is great. Plugged into my computer interface, great. Back to the amp, great. Into the Kemper, gated and distorted (unless I turn the volume down). Back to the amp, great....

  • Again, if this is the case, then how is it that it only happens when plugged into the Kemper and not when plugged into any other processor, amp, mixer, etc/? It's not intermittent. I'm sitting here going back and forth right now. Plugged into the amp, everything is great. Plugged into my computer interface, great. Back to the amp, great. Into the Kemper, gated and distorted (unless I turn the volume down). Back to the amp, great....

    OK, at least that test does confirm it isn’t an intermittent connection fault. You need to raise a support ticket with Kemper to find out what is going on in your case.

  • Response from Kemper:


    Could be an impedance issue:

    Unfortunately, I do not know your guitar and the specs but I can provide you with the Profiler Input specs:


    Front INPUT: 1⁄4-inch TS unbalanced, dynamic range >108 dB, impedance 1 megohms

    ALTERNATIVE INPUT: 1⁄4-inch TRS balanced with ground lift, dynamic range =105 dB, impedance 825 kohms

    RETURN: XLR balanced, 1⁄4-inch TRS balanced with ground lift, dynamic range =105 dB, impedance 825 kohms

  • Hi Nightstick did you get anywhere with your issue.

    I am having EXACTLY the same issue and I know it is not my Guitars.

    I use a Fender Strat & PRS both not active, no batteries.

    For years I have had no problems but now it is distorting.

    I have tried updating the OS, I have changed leads, I can't see where the issue is.

    Why would all the settings suddenly need changing when I haven't touch it...I don't get it!!

  • I did, but it sounds like your issue may be a little different. The microphone system in my acoustic is giving off DC voltage and sending it into the Kemper - which it shouldn't be doing. So the mic system does need to be repaired or replaced. The Kemper just seems to be much more sensitive to that voltage than any other device since everything else I plug the guitar into functions just fine. Only the Kemper has issues. For now, I'm just running a separate tuner pedal between the guitar and Kemper as a workaround until I repair the mic system.