PA speaker hum at certain venues

[Al Krow]

Been getting hum through the PA speakers (RCF 932 and previously 912s) at certain venues. Assuming it's down to the electrical interference from the wiring. Is there anything that can be done to minimise?

[Bill Fitzmaurice]

Hum is almost always caused by grounding/earthing issues with the wiring and there's seldom anything you can do about it. 

[warwickhunt]

Worth looking at whether all the sockets are on the same ring and seeing if you can plug into one set of sockets; obviously being aware of the load placed on the socket.

[TimR]

Pubs? Check for a freezer or a light dimmer switch. 

[Phil Starr]

14 hours ago, Al Krow said:

Been getting hum through the PA speakers (RCF 932 and previously 912s) at certain venues. Assuming it's down to the electrical interference from the wiring. Is there anything that can be done to minimise?

Running everything through a single socket means you have a single earth for all your gear, which might help. Unless you are using incandescent lights you won’t overload a 13A socket. As has been said in other recent threads use a plug in mains tester to check the socket first. I used to check every time but now only check if there is a problem. If the socket is faulty you shouldn’t use it and you need to report it to the venue. 

 

You should be able to isolate the channel or channels which are causing the problem. Mute them all and open one at a time. It might be just one bit of gear that is picking up the hum or even just one of your cables that has a fault, Hum can’t be transmitted at wireless frequencies from a noisy, poorly screened nearby appliance. If so you could just move the amp or whatever away from the source. If one piece of your kit is causing the problem at several venues then get a tech to look at it. A lot of vintage amps can be poorly screened and single coil pickups are great radio receivers 

[Al Krow]

Thanks Phil - typo? "Hum can be transmitted..."

 

Just to prove I read your comments word for word, haha!

[Phil Starr]

4 hours ago, Al Krow said:

Thanks Phil - typo? "Hum can be transmitted..."

 

Just to prove I read your comments word for word, haha!

Hmmmmm

 

[Phil Starr]

Spellcheck on my tablet I guess.

 

[Al Krow]

48 minutes ago, Phil Starr said:

Spellcheck on my tablet I guess.

 

 

That can't be right? 😅