PDA

View Full Version : Turntable Earthing



Beechwoods
20-07-2008, 15:57
I have a Pro-Ject Debut Mk I turntable, entry-level but good sound for the money. It has 2 unbalanced RCA phono out's that go into a phono pre-amp. It also has a single earthing wire, with bare wire termination. A proper earth is essential to avoid hum. Up until now I've made do with screwing it temporarily to the chassis of another item of kit but wanted something more permanent. I figured I could wire the earth only of a 3 pin mains plug, and run that back to the earth cable of the turntable.

What do other folks think / do? My amp doesn't have an earthing point. My kit is also in a loft room so it's difficult to get a wire down to ground level to terminate at a proper earthing pole.

I need to get this sorted - I can't bear any hint of hum on my system!

Cheers :)

anthonyTD
20-07-2008, 16:27
I have a Pro-Ject Debut Mk I turntable, entry-level but good sound for the money. It has 2 unbalanced RCA phono out's that go into a phono pre-amp. It also has a single earthing wire, with bare wire termination. A proper earth is essential to avoid hum. Up until now I've made do with screwing it temporarily to the chassis of another item of kit but wanted something more permanent. I figured I could wire the earth only of a 3 pin mains plug, and run that back to the earth cable of the turntable.

What do other folks think / do? My amp doesn't have an earthing point. My kit is also in a loft room so it's difficult to get a wire down to ground level to terminate at a proper earthing pole.

I need to get this sorted - I can't bear any hint of hum on my system!

Cheers :)

hi,
does your phono-stage use a mains earth? if so, the turntable earth should realy go to the same earth potential as the phono circuit.
anthony...:)

Beechwoods
20-07-2008, 17:52
hi,
does your phono-stage use a mains earth? if so, the turntable earth should realy go to the same earth potential as the phono circuit.
anthony...:)

I don't believe it does. It runs from a 12v dc wire from the back of an integrated plug/transformer that goes into the wall; no earth :(

KMair
21-07-2008, 00:42
Have you tried without any ground? Try it and see if it doesn't go away or lessen.

I used to use a set of MIT phono innerconnects which were very heavy, so heavy that they eventually pulled an internal ground loose in my reciever.
It was maddening to find the source of the hum. I finally took the reciever to dealer and that was when the broken internal ground was discovered. When I brought it home I left all grounds off and was amazed at how quiet it was. You literally have to put your ear within inches of speaker to hear any noise! Playback improved dramatically!

anthonyTD
21-07-2008, 09:30
I don't believe it does. It runs from a 12v dc wire from the back of an integrated plug/transformer that goes into the wall; no earth :(
in that case, you should run an earth to the next piece of equipment in line eg, pre-amp/ power amp, and try that, both these devices should , if they have a metal enclosure be at earth potential from the mains supply.
hope this helps.
anthony...:)

Beechwoods
21-07-2008, 14:27
It sounds like I'd be best running a proper flylead from the chassis of my Amp back to the turntable. I'll give this a go and report back...