a little bit of hum............... - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 1st June 2006, 06:27 PM   #1
diyAudio Member
Join Date: Aug 2002
Location: Suffolk ,England
Default a little bit of hum...............

Hi guys, Ive got a hum problem, just need some feedback, i am currently monoblocking, Monobridging two Behringer A500 *pro Amps, and on the left channel i seem to be getting some hum. I have it in a system with a rotel pre amp, Cd player, turntable, Cassette deck

Before i say any more, sometimes i run my finger along the front of my Cd player and amp which is metal , and there is a small voltage ,static running across them. I have a small studio, and the hum is present in there, also downstairs it happens to the hifi in the front room. a small charge at times. My television upstairs has the same background interference. I have had that for 4 years, and beforehand a Audiolab 8000SX times 2, and that never gave off hummed so much.

anyway any info ideas, could be poor grounding in the power amp, the interconnects, i have unplugged everything , interconnects and all

So maybe a ring main problem? Its a bit of a lottery really.

thanks for any info
  Reply With Quote
Old 1st June 2006, 08:20 PM   #2
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
Netlist's Avatar
Join Date: Jan 2003
Itís difficult to confirm if the hum and the voltage present on the metal parts of the system are related with each other.
I however would advice to let an electrician have a serious look at the ground in the house and studio. Being in the consumer business, I frequently encounter houses with bad or no grounds and itís not the first time I got shocked by the cable antenna or the video and TV equipment.
It might be a solution for the hum as well.

  Reply With Quote
Old 2nd June 2006, 01:07 AM   #3
jaycee is offline jaycee  United Kingdom
diyAudio Member
Join Date: Apr 2004
Location: Norwich, UK
You need to check the earth bonding in your house. If you are getting potential build up on metal earthed items then this means your house has a poor earth.

I'd suggest getting a qualified electrician to do an EFLI test.
  Reply With Quote
Old 2nd June 2006, 01:09 AM   #4
diyAudio Member
Join Date: Aug 2002
Location: Suffolk ,England
thankyou guys, I think i should get an electrician to check it out, its been going ona few years now, with currents running through cables it shouldnt.
  Reply With Quote
Old 2nd June 2006, 02:14 AM   #5
diyAudio Member
BrianDonegan's Avatar
Join Date: Dec 2004
Location: TPA HQ (The Basement)
Sounds like a bad neutral coming from the pole (power company pole). Maybe a bad line transformer. They should be able to clear it up.
  Reply With Quote
Old 2nd June 2006, 03:20 AM   #6
lndm is offline lndm  Australia
diyAudio Member
Join Date: Mar 2006
Location: nsw
Default Re: a little bit of hum...............

Originally posted by emperor Ive got a hum problem, just need some feedback,

If you take a walk around your house and locate the ground stake, there's a chance you may notice something obvious, like corrosion (not a substitute for a professional opinion.
  Reply With Quote
Old 2nd June 2006, 04:50 PM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
being British based you are unlikely to have an earth stake and similarly no pole transformer.

Depending on which earthing system your power company installed will determine whether you have a true earth or an earth shared with the neutral incomer.

Whichever, I would go for a professional check over just for peace of mind. There is a downside, if they find a problem they will condemn it and may switch you off until it's fixed. You are then over a barrel, and price no longer seems relevant.

ps, you can buy a cheap plug top with a tester built in that checks for the presence of Live, Neutral and Earth and that they are on the correct poles. But it does not check the quality of your system connections.
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote
Old 2nd June 2006, 05:34 PM   #8
poobah is offline poobah  United States
diyAudio Member
poobah's Avatar
Join Date: Nov 2005
These guys are "spot on" if that's the correct term. I have sometimes foolishly ignored tingles on equipment only to find out sometime later that I was touching a solid 120 Volts AC... damp socks or barefoot is a good (BAD) way of finding these things.

Take along wire and tie it to a water pipe. Go around your house with a meter... you might be shocked (literally) at what you find.

Oh, BE CARFULL with that long wire, don't ground yourself!

EDIT: speeling... again!
  Reply With Quote
Old 2nd June 2006, 05:49 PM   #9
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
Netlist's Avatar
Join Date: Jan 2003
I'm glad to see the words of warning given by people in this thread. As stated many times and very nice phrased by SY some time ago: "Dead is very permanent."

  Reply With Quote
Old 2nd June 2006, 05:53 PM   #10
PMA is online now PMA  Europe
diyAudio Member
PMA's Avatar
Join Date: Apr 2002
Location: Prague
Unfortunately we often face "hum" and "noise" problems . Sad to see sometimes ....
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

New To Site? Need Help?

All times are GMT. The time now is 07:09 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2