Humming through XLRs

[Mark Dunlop]

I recently bought an Audiolab combo - the 8300CDQ & 8300 XP and decided to try the XLR ouputs for a wee change. I then bought replacement speakers - B&W DM602 S3s out, ATC SCM 11s in.
There's a hum from the speakers when I select the XLR output on the 8300XP which is not present when I select the RCA outputs. I don't think the B&W speakers hummed, but I've sold them and now can't be sure. XLR leads are new from Designacable. RCA leads are home-mades.
Wasn't expecting XLRs to hum, and certainly not when RCAs don't... anyone got any clues?
Cheers
m.d.

 

[abacus]

Could be a faulty unit, also the XLR are at both ends and not going from XLR to RCA.
To be honest, for such a short length there is no advantage to XLR over RCA.

Bill

 

[Mark Dunlop]

Could be a faulty unit, also the XLR are at both ends and not going from XLR to RCA.
To be honest, for such a short length there is no advantage to XLR over RCA.

Bill

Cheers, Bill. I only decided to use XLRs for the s & giggles, really. I would say the sound is a little louder through them than the RCAs and the hum isn't apparent when listening.
I had a hum from a Rotel cd player once that I fixed by using a different power cable, but this is a different kettle of fish.
m.d.

 

[daytona600]

XLR wil be almost twice as Loud +6db on Balanced outputs compared to RCA
Should be no Hum even with hundreds of feet of cables unless 50hz picking up mains frequency from power cables

 

[Gray]

XLR leads are new from Designacable.

.....so they're probably ok.
But, if you've got a multimeter, you may as well check to confirm all is well.

You'll see the XLR pins are numbered 1,2,3 (printed on the plastic close to holes and pins).
Use continuity test to confirm all go to the corresponding numbers, plugs to sockets.
Pin 1 is the screen.
Will (should) have been tested prior to sale, but no harm in checking.