earth bridging

[cider]

thanks for everyones help

 

[Spark123]

I'm not sure what leads you are using, I'd imagine you need a lead which connects one phono plug to channel 1 XLR and another lead which connects the other phono to channel 2 XLR, thinking channel one and two are referring to left and right??

 

[cider]

thats what im using now but have a constant hum until i unplug one of the leads from the amp end. could this mean duff leads?

 

[cider]

ok i have now had a response from a hifi forum telling me i have an earth problem pos in the house wiring could this be anything to do with the fact weve had a new consumer unit installed???

 

[ban-all-sheds]

hi-fi people have some very strange ideas about electrics - some of them way over the line into loony fantasies.

I'd check out the leads and equipment first (e.g. open up the case and look for broken earth/screen connections).

It might also be worth asking on a pro audio site, e.g. blue-room.org.uk

 

[stargazer]

I used to build amplifiers in my misspent youth. Problems with the household earth? I don’t think so. Humming was usually caused by poor screening or connections somewhere.

Currently got a mixer and ipod plugged in

I assume you've tried removing the ipod and using another audio source, like a CD player?

the noise only goes if i unplug one of the two inputs to the amp from the mixer.

Does it make a difference which input you plug in and which you leave out?
Does the humming come from the left, right or both speakers?

have a constant hum until i unplug one of the leads from the amp end. could this mean duff leads?

Possibly, wouldn't hurt to change them - try the simple stuff first.

I see the amplifier has a ground lift switch. Have you tried that?

 

[cider]

Currently got a mixer and ipod plugged in

I assume you've tried removing the ipod and using another audio source, like a CD player?

yep

the noise only goes if i unplug one of the two inputs to the amp from the mixer.

Does it make a difference which input you plug in and which you leave out?
Does the humming come from the left, right or both speakers?

seems to be associated with one lead whichever plug.

have a constant hum until i unplug one of the leads from the amp end. could this mean duff leads?

Possibly, wouldn't hurt to change them - try the simple stuff first.

dont know what leads i should buy as amp and mixer have different sockets to use

I see the amplifier has a ground lift switch. Have you tried that?[/quote]

fiddled with all that but being a fwit dont know where they should be set

 

[sparkyspike]

Get a pair of balanced jack-to-jack leads, that'll do the job.

 

[cider]

thanks.

one last question, i assume jacks are not the small type plug which fits into standard home hifi stuff as there are no terminals that size on the amp.
sorry but i am a numty

 

[RF Lighting]

Clicky

 

[cider]

that answers my question. top man
now i can crank my system up new yrs eve
you'll probably hear it where ever you are

 

[sparkyspike]

Get these ones:

TRS balanced leads

 

[RF Lighting]

Why?

They are mono inputs into the amplifier, so stereo leads are pointless

 

[sparkyspike]

Not pointless. The mono inputs are balanced, seeing as they are in parallel to the XLR inputs. So the 3rd core (the screen) in stereo cable can be used as a balancing wire, whilst the two insulated cores are the mono signal wires. Using two balanced cables gives two mono inputs. If hum is being experienced, using balanced leads could help.

Using TRS to XLR will have the same effect, but there is then the chance of having the wrong terminals connected.

 

[stargazer]

http://www.mediacollege.com/audio/balanced/cable-balanced.html