Help with Hum

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Peter J

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Help with Hum
« on: 5 Mar 2013, 06:57 pm »
Nope, not looking to add hum :icon_lol:

That said, I'm looking for some advice. I've got a little hum from speakers...not huge, but noticeable when nothing is playing.

System is CAPS 3 server > Wyred 4 Sound DAC-2 > Eastern Electric M-88 integrated.

 This seems a little weird to me but it appears to be the connection between DAC and amp. If theres any cable (balanced or single-ended) plugged into inputs from DAC the hum is there. Doesn't matter if DAC is on or even plugged into power or usb from server, just cables in outputs going to inputs. Unplug all cables at either end and it's dead quiet, so I don't see how it could be anything upstream from DAC.

So I think I've got it isolated, just don't know what's causing it or how to eliminate. Is this a ground loop problem? It does sounds like a 60 cycle hum.

Any ideas?

doctorcilantro

Re: Help with Hum
« Reply #1 on: 30 Dec 2013, 06:06 am »
Did you solve your issues?

G Georgopoulos

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Re: Help with Hum
« Reply #2 on: 31 Dec 2013, 01:00 am »
Nope, not looking to add hum :icon_lol:

That said, I'm looking for some advice. I've got a little hum from speakers...not huge, but noticeable when nothing is playing.

System is CAPS 3 server > Wyred 4 Sound DAC-2 > Eastern Electric M-88 integrated.

 This seems a little weird to me but it appears to be the connection between DAC and amp. If theres any cable (balanced or single-ended) plugged into inputs from DAC the hum is there. Doesn't matter if DAC is on or even plugged into power or usb from server, just cables in outputs going to inputs. Unplug all cables at either end and it's dead quiet, so I don't see how it could be anything upstream from DAC.

So I think I've got it isolated, just don't know what's causing it or how to eliminate. Is this a ground loop problem? It does sounds like a 60 cycle hum.

Any ideas?

if you unplug all cables the amp is quite?,this tell us the amp is ok
you may have a problem with dac,try using another source (cdplayer etc)
with the amp,is the hum gone? if not,your amp could be inducing hum!

cant be more specific since i dont know your components

happy new year

cheers :green:

doctorcilantro

Re: Help with Hum
« Reply #3 on: 31 Dec 2013, 07:08 am »
What about shorting plugs into amp? One would expect to hear dead silence correct? Would this be better than no input? I would think you would get hum with no input, but speakers connected.

Ericus Rex

Re: Help with Hum
« Reply #4 on: 31 Dec 2013, 01:58 pm »
What about shorting plugs into amp? One would expect to hear dead silence correct? Would this be better than no input? I would think you would get hum with no input, but speakers connected.

Roger Modjeski has said in his Music Reference circle that you must always use shorting plugs when testing out an amp's noise level.  Leaving the inputs open is not the same thing.