Problem with True Impedance on Kemper Fuzz

  • I just switched over from a rack profiler to a new stage unit. The True Impedance option sounds quite nice on the Kemper fuzz, but it's behaving very strangely when I turn that block off using a footswitch. The impedance setting changes immediately (I can hear the sound get brighter), but the fuzz does not get bypassed for another four or five seconds! If I disable the impedance check-box the effect bypasses immediately on press of the footswitch. Anyone else seeing the problem? I already tried a factory reset and restore, but no change in the behavior.

  • I reported the problem to Kemper support who tell me this is normal behavior. From the manual section on the Kemper Fuzz:

    Code
    You will notice an audio drop-out when switching, too. This drop-out will also occur whenever you switch from or to a Rig with a fuzz with active “True Impedance”. This drop-out cannot be avoided as the hardware impedance dramatically changes the incoming level of your guitar in an instance. Consider carefully whether you will make use of the volume pot advantages or benefit from an artifact-free switching.

    What threw me is that it's not really a "drop-out". The impedance changes instantly, brightening up the sound, but the fuzz effect does not bypass for almost four seconds. This all seems a bit odd, but not being privy to the system architecture there may well be good reasons for it.

  • Thanks very much for confirming what I suspect. The delay I'm seeing is unlikely to be intentional or expected. I can tolerate a short glitch before and after soloing, but having to wait many seconds before the fuzz bypasses is a non-starter.

  • I've had one open since the day I started this thread. As I mention above, they told me it's expected. But it doesn't match your experience nor can I believe they would have shipped software that took many seconds to bypass the effect. I pinged them again on the issue but I have not heard back.

  • I just tested on my Player. There is a lag of maybe half a second or more before the Fuzz kicks in. I assume this is the audio Drop Out that can't be avoided due to how the True Impedance Buffer works.

    However, like others have mentioned it definitely doesn't seem to turn off immediately. When I bypass the Fuzz the main fuzz effect does turn off immediately but there is a residual fuzz (like having the fuzz effect with the Mix turned down) for a while which then fades out to nothing. I can only assume that is bug :?:

  • Rather than re-shuffling the DSP code I would have opted for switching actual caps in and out with small relays. That would be virtually instantaneous in both directions.

    I don’t think they are just shuffling DSP code - if they were then us toaster owners would get it via an upgrade. It’s advertised as a physical thing so (if I understand it correctly) it’s physically altering something.

    From their reply to you, they’re saying you can turn the physical impedance feature off and get instantaneous switching *or* have the feature on and experience a lag.

    I don’t know why the lag occurs either but I’d guess it’s that the physical change is going to cause upsetting volume differences and cause a massive speaker thump if you do it instantly. There will be a legitamate reason for it as I’m sure they’d rather not have lag either.