remote screen-brightness affected by cable

  • Noticed something strange today using an "approved" 3rd 6 metre party tour-grade ethernet-cable;

    if i boot my KPA with remote attached the screen is nice and bright with a screen brightness set to a value of "10,000"

    However, if i plug the remote in after the KPA has booted the remote brightness is considerably less.

    I can crank the brightness-setting up to max and it is still not as bright as the mid-brightness setting available when booting with remote attached.

    As part of the remote boot-up process, you should notice during the first few seconds the remote brightness increases from dim to max brightness over a short period of time before going off (this is normal) then, shortly after, coming back on and entering normal/running conditions

    With the "rogue" ethernet cable this dim-to-bright process lasts about half the duration.

    As an experiment, I used a bog-standard 3 metre computer ethernet cable and it worked fine, so it appears that the cable-length may be a factor.

    Any other users have any tips or experience regarding cable types and lengths?

  • I've read about some users having their pedal reboot as if losing power or not getting a good enough power-supply by using lesser-quality long cables. (Suggestions made were to employ a Power-Over-Ethernet device)

    Anyone know what voltage the remote pedal needs and tolerance? (is there a standard for POE injectors?)

    What difference is there between the power supplied from the KPA and that required by the remote?

  • KEMPER has not "approved" any 3rd party cables. We recommend our original Ethernet cable. Even cables with lowest resistance must not exceed 20 feet. For longer distances use PoE. With PoE you are free to use any Ethernet cable up to 300 feet.

    Please refer to the Main Manual chapter PROFILER Remote paragraph Cabling.

  • The issue here is not likely a voltage issue but an amperage issue. The cable you are using likely has very thin wire in it. The electrical properties change as the cable thickness increases allow the cable to deliver more power to the device over the length. For the 6 meter length this generally should not be a problem. I would check out another cable manufacturer. If you want to go long (over ~30 meters) this is were Kemper has indicated you can get into trouble. The heavier cable is the solution. A standard ethernet cable is likely awg 24. The kemper cable is awg 22( the lower the value the thicker the wire). If you have a High flex cable it is likely awg 26. If you want to go long using a thinner wire the POE injector is the proper solution. The kemper pedal is an Ethernet device. The circuitry used by the communications logic appears to support the specs for the POE based on posts by others on the forum. If you have questions let the forum know. For the POE information just search the forum.

  • The thing I don't get in the PoE injector story:

    It's true that tinner cable means more resistance, thus more voltage drop over the cable is the power consumption of the powered device increases. Also length increases resistance. So wrong cable or lengthy cable means not enough remaining voltage to operate the electronics of the remote. And the higher the brightness increases, the more power will be consumed, the more the voltage will drop, and thus, the sooner the remote will fail to boot...

    But a power over ethernet injector theoretically cannot change this situation: if both the Kemper and a separate PoE injector provide 48V on the ethernet cable, why on earth would that be a problem with a Kemper and a less than ideal cable, and no problem with a PoE injector and the very same less than ideal cable??

  • I sat down with one of the Electrical Engineers that I work with. He explained the practical information around this concern. Kemper when they designed the power section that is used to provide power to the Remote intended it to be used with the Cable provided. The Kemper cable is 22 AWG wire. This wire is larger than traditional ethernet cable which is normally 24 or 26. (The larger the number the smaller the diameter of the cable.) The smaller wire results in more resistance to the flow of energy on the wire. Therefore, if you use a standard ethernet wire of the same length as the kemper wire it is possible that you could experience problems with the remote. This would be due to insufficient power making it down the wire to the device because of the additional resistance of the wire. Kemper calculated the resistance of their wire and designed the power supply in the KPA to deliver the power over the 22 AWG wire. If you substitute the cable you are changing the resistance in the equation and you likely will get unexpected behavior.

    The use of a POE (Power Over Ethernet) allows you to overcome the problem. The POE has its own power source which has been designed to provide the power over long run with the higher resistance wire. The power source on the POE is designed to be able to deliver the power over the long distance. You can then make use of standard ethernet cables for your long runs. I believe the POE specification indicates that you can connect a device up to 100 to 150 feet away.

    I hope this helped. My comments here do not in any way intend to question anything that Kemper has done with the design of the Remote Interface. They designed the product according to their specifications and the product works as they intended. If we choose to use cables and distances that they did not intend then the problem ownership is our own not theirs.