Help eliminating hum.

  • Hello all,

    I have a PRS custom 22 semi hollow with a Hum, narrow field, Hum pick up configuration.

    When I play at church I have an awful loud hum and microphonic issue.

    However, at home, either through my KPA or my tube amp. no hum.

    I am using the mains power cable supplied with my KPA.

    I dont know what else to do. i have heard of using a power conditioner but I was hoping there is a setting I can change or something else I can do.

    Please help.

    Thank you,

    Riley

  • Are you the online ohne Witz this issue? In Some places they have a system for people with a hearing disorder (sorry, I don't know the correct Name). Such systems can cause such issues.

  • there is a hum on kemper, is true, also if you switch on the ground lift hum change, but not disappear. I think the best thing you can do is to have the output level on your kemper high enough (avoiding to clip the signal) to keep the volume on mixer low so the hum will be very low, cause it not increase if you turn up the volume of the output

  • there is a hum on kemper, is true, also if you switch on the ground lift hum change, but not disappear. I think the best thing you can do is to have the output level on your kemper high enough (avoiding to clip the signal) to keep the volume on mixer low so the hum will be very low, cause it not increase if you turn up the volume of the output

    If you have a permanent hum something is wrong. It should be silent in normal conditions. Could be related to power in your area or external interference (such as pickup noise) the Kemper shouldn't be introducing hum.

  • I am not smart, I just play smart person on TV 8o


    If nothing has changed except the venue, hum is almost always a ground loop. If you have two pieces of gear connected to each other at a distance, the ground voltage potential of each unit will be different. So currents will travel on the wires between the units and show up as hum in the circuits.


    Since you are on the Kemper site we have to assume you are connecting the Kemper to a mixer that is very far away. The mixer is not only far away but is probably on a completely different electrical circuit than you are. This will mean ground loop currents and hum.


    If switching the ground options on the Kemper do not help you may need an isolator. This is a box that uses a transformer to isolate the two devices electrically from each other. This stops any low frequency ground currents from flowing. Electrical power is 50 or 60Hz.


    You can also get hum from devices around you that are creating electrical noise. This noise is picked up from your pickups and is coming thru the air (in most cases). If you are using your humbuckers and getting loud hum, something would have to be making a lot of noise. Since this noise is being transmitted thru the air it will be a distance squared function. Meaning, the closer you are to it the louder it will be. So you would need to move around and see if it gets better or worse. Many times just spinning around can cause the hum to come or go.


    You are saying hum and microphonics. If you have ground and noise transmission issues your hand touching the guitar strings can act like an antenna. Does this noise come and go when you hand is touching the guitar strings/pickups/etc?


    Other options would be the ground circuits at the venue are not wired correctly or have ground cheater plugs on them.


    Or if you have pedals plugged into wall warts. The hum can come from poor power supply filtering. Batteries do not need filtering and are 100% isolated so they never hum. If your Kemper is on one power circuit and your pedals are plugged into a different circuit, you will have ground loop hum.


    Best of luck to you, hopefully the pros here can give you some great advice.

  • As has been said, a ground loop is a likely culprit.


    Power conditioners have their place, but I’ve never had one eliminate hum when added.


    Does your church use fluorescent lights? If so - that’s likely contributing, if it isn’t the outright cause. Fluorescent bulbs emit what is called 60 cycle hum. It can either be transmitted through the power circuit, or more commonly it’s coming through your pickups.


    Is the hum directional? Meaning, if you turn your guitar, or aim your pickups towards the floor/ceiling does the sound change or even go away?


    Does it do it in the room with the lights all off? Another room of the same building?


    I had this happen with a Telecaster that had 50s spec pickups. Every guitar made noise in that room….but that Tele under the lights of that auditorium acted like channeling hum was it’s purpose in life.


    Infuriating, to say the least.


    Keep eliminating possible sources (lights, room, power circuit….try a different guitar through the same gear, same guitar through someone else’s gear…..set up at a third location (not the church, not your rehearsal space). Also - if you’ve got pedals in your chain, remove them completely.


    Still doing it? If not…start removing individual pedals to find the offender(or the cable involved?)


    Keep limiting the variables and you’ll find the culprit. Then you can sort out how to address that problem. (FYI…there may be more than one cause….so, y’know…..fun…🙄)


    Yeah…. it’s a gigantic pain, but once you find the problem it’s worth it.


    Good luck!

    “Without music, life would be a mistake.” - Friedrich Nietzsche

    Edited once, last by Ruefus ().

  • Thank you all so much for the great advice.

    I am going to try changing the ground on my KPA and getting a power conditioner.

    I am going from my KPA to the mixing desk a long ways away. and the PA, mix, input system the church has is an absolute mess of cables, power, mics, network cables and I dont know what else.

    Maybe I will ask to move my location on stage and see if that helps also.

    Wish me luck!

    Riley

  • TomR I think you are referring to an induction loop.


    The other option could just be a groundloop. Are you connecting to the mixer AND something else simultaneously when at church but not doing so at home? Try flipping the ground buttons on any output in use.

    Ah, yes. Thanks. :)

  • As has been said, a ground loop is a likely culprit.


    Power conditioners have their place, but I’ve never had one eliminate hum when added.


    Does your church use fluorescent lights? If so - that’s likely contributing, if it isn’t the outright cause. Fluorescent bulbs emit what is called 60 cycle hum. It can either be transmitted through the power circuit, or more commonly it’s coming through your pickups.

    Lots of good tips here. Lights can always be an issue. THe most critical issues I have endures were induction loops. But that would affect all guitars / basses on that specific venue.