Cambridge Audio CD5 Hum

[Terryff]

Noticed last night that my cd player has a significant hum. I tend to not switch off my Hi-Fi components, but have now started, both because the new maramtz amp i have draws a fair amount of 'leccy and also due to the cd player humming. Anyone got any idea what it might be, as it obviously interferes with my quest for clean and clear hi-fi?

 

[Tony_R]

Terryff:Noticed last night that my cd player has a significant hum. I tend to not switch off my Hi-Fi components, but have now started, both because the new maramtz amp i have draws a fair amount of 'leccy and also due to the cd player humming. Anyone got any idea what it might be, as it obviously interferes with my quest for clean and clear hi-fi?

Are you sure it's the CD5 humming?

I seem to recall there were some hum issues with the PM7200...

 

[Terryff]

I think so, as when i turned off the cd player it went.....

 

[Tony_R]

Terryff:I think so, as when i turned off the cd player it went.....

Definately CD player then...

Can you pin it down any particular channel? Or is it on both?

Also - has this only just started, it was it there from the time you installed the amp?

Do you have a headphone amp, to which you can plug the CD player into and check?

Is there any other equipment connected besides the CD player?

I'm just trying to rule out the possibility of an earth loop or similar here, although IIRC the Marantz isn't earthed to the mains, but I'm not sure about the CD5...

 

[Terryff]

I will try all this tonight, i have a mains conditioner on, so i think it will actually be the cd player. I have only just noticed it, though in all honesty it might have been going on before the marantz. I have a turntable connected and earthed through the amp also. might try routing my dab radio through the cd circuit to see if it is the actual circuit, have a funny deeling though that the hum comes directly from the cd unit, so i guess i almost answer my own question there as to the culprit. Guess i need to look at another one, don't think its that viable to have them repaired these days?

 

[Tony_R]

I'm willing to bet you have some kind of earth loop.

Try plugging *just* the Maranzt and Cambridge directly into the mains (bypassing your filter) and then try them.

I reckon you'll find your problem will have gone away...

Unless of course you're trying to justifiy buying a new CD player and you're talking yourself into it...

Perhaps "upgradeitis" has struck...

 

[Terryff]

Upgradeitis well established, though i had not wanted to change this yet, as a dac and pc music were next targets. If i have an earth loop what implication, asides the hum, does that have and how might it be fixed?

 

[Tony_R]

Terryff:Upgradeitis well established, though i had not wanted to change this yet, as a dac and pc music were next targets. If i have an earth loop what implication, asides the hum, does that have and how might it be fixed?

The only implication with audio is the hum. Most equipment used by live bands (amps / mixers etc.) has an "Earth lift" switch which actually disconnects the earth for that specific device (as it will already be earthed via some other path - hence the loop).

The remedy in this case is firstly to find which device is causing it, and then take appropriate steps from there.

This usually involves disconnecting an earth wire in the mains plug of the offending item. (although professional advice should be sought before doing this!).

As described above - an earth loop is formed by having two or more items connected to earth, but usually via some convoluted route.

So.. this could for example be that your DAB radio aerial is earthed at some point. That could definitely cause a loop.

Which is why I suggest a process of elimination, before taking this any further!