tyre monkey

I know it is not computer related, but can anyone help. I have recently moved house, and re-setup my hifi/home cinema system. I have a Yamaha processor for the home cinema, and a normal amp, which drives the left and right front speakers.

I have got a hum through the speakers, that i never had before, The TV is not connected to any RF signal or satellite box, only connected to the DVD player, I have tried different leads, cables, and pluging the amp into another wall socket. Nothing seems to improve it, any tips or suggestions???

boomer

Do any signal or speaker cables run alongside any mains cables (including ones under floorboards or in walls)?

Doc

Have you tried a surge suppressor plug?
£7.99 from www.maplin.co.uk code QL98G.

Try plugging the amp into a different ring main in your house. Fridges and freezers often cause a hum and this test would at least point you in the right direction.

kryten

Is there a big metal 'phono' ground binding post on the back of the amp? Does the noise stop if you touch it?

Is everything powered from the same point?

It could be a ground loop. Most HiFi isn't actually earthed and even something as simple as different length power cables can cause issues!

scoobs

First thing to try is removing the earth from the amp mains lead.

The hum is usually due to and earth loop somewhere, e.g. all you attached gear is earthed at two different points. If this cures it then, it's up to you whether or not you are happy to leave you amp without the earth dettached.

You could of course buy a load of pro gear off me, which runs off ballanced audio cables and will solve your hum problems


Scoobs

GavinP

Yamaha amps do seem to be very sensitive to mains interference in my experience - I had two (DSP-E492 and DSP-A592) before getting a Sony and both were affected by mains noise.

This site is good and they will send you a free booklet about mains supplies and hi-fi equipment which makes for VERY interesting reading....

EDIT: Or you can download it from Here in Adobe Acrobat format.

I used a single RFI/Surge adapter from Homebase for £20 which worked well. You plug it between the amp plug and wall socket.

Thanks

Gavin

[Edited by GavinP - 1/23/2002 8:50:40 AM]

tyre monkey

Thanks for that, will try all of the suggestions, I am sure I have changed something or a connection when moving.

The flat is newish and in a large block, I am wondering if I am getting a bad power supply... will try to eliminate it before looking for a "power cleaner" type product

Cheers

Jamie