advertisement


TT Grounding

J

jamington2004

pfm Member
Hi hoping to be spoon fed some nuggets of advice on grounding from a knowledgable fishie or 2 :)

My turntable has a grounding wire attached to the underside of the bearing assembly, as well as the more traditional ground wire alongside the tonearm cable.

I have 2 issues to try and fix - one is standard hum which I could do with a few simple tips on (plug phono stage and TT in same socket / different sockets etc?)

It is fairly constant - fades in and out a bit if I move the phone stage / cables around. So while the cupboard it's in is full of electronics - I don't think it's RF interference (maybe wrong :) )

Second is when I touch the finger lift, or when I put the turntable weight on - I get static / crackle coming through the the speakers.

Hum is most annoying as it makes me feel like it could be getting in the way of the finer details of the music

Crackle when touching stuff less so - but would love to know where I should stick that bloody spare grounding wire!!! (careful now.....)

Thanks in advance
Jamie
 
What turntable and phono stage is it? I ask as different logic applies in different situations, e.g. whether the phono stage has a mains earth, whether the deck has a metal chassis/plinth/arm board etc.
 
Ah - I didn't think it mattered

It's a DIY valve phono stage with a pretty hefty power supply inside and metal case - and a grounding terminal which I screw the tonearm ground wire into

And Basis Debut Gold Standard which is mainly acrylic - but lead inserts underneath the platter and armboard. And an SME V fitted to it

Thanks so much for trying to help :)
 
Just consider the main bearing earth to be a means of allowing static charge in the vinyl to disipate, you should be able to connect that anywhere without causing buzz. I suspect your issue will be an earth loop betwen your phono stage and preamp, you may find you need to lift the earth on one of them.
 
Ah ok - interesting re bearing cable thanks :)

I don't have a pre amp - only a little Devialet router that transmits to the speakers via Ethernet. Otherwise in the chain there is an ADAC to get the sound converterted and into the digital router

And a wifi router and sky box :)
 
well I found on my system that mc cartridges ( the ones I used ) need to have the arm /turntable earth connected to the cartridge ground whereas the mm ( the one I now use ) need them to be separate. That didnt solve the hum completely and there still was the sensitivity to touching the arm though - my preamp/phono has a floating earth ( ie not a real one no earth pin in the case socket) and I had to make a real one from a mains plug and run that to the tag on the preamp/phono that you connect the turntable earth to, to make a real earth to the preamp/phono. So just a few ideas to try.

In my case the bearing is connected by a metal strip to the arm fixture( under neath - Roksan Xerxes)
 
Has this problem always been there? If so I suspect arrangements in your DIY phono amp.

Did you build this yourself? ( i am guessing not)
Is it a recognised (well known) design?

If the problem is 'new' then something else could be afoot
 
JensenHealey said:
Has this problem always been there? If so I suspect arrangements in your DIY phono amp.

Did you build this yourself? ( i am guessing not)
Is it a recognised (well known) design?

If the problem is 'new' then something else could be afoot
Click to expand...

Sorry should have said it's the same with other phono stages - even a brand new Dino MK3

Pretty sure the buzz has always been there since previous TT - but the static / crackle when I touch stuff seems new
 
mercalia said:
well I found on my system that mc cartridges ( the ones I used ) need to have the arm /turntable earth connected to the cartridge ground whereas the mm ( the one I now use ) need them to be separate. That didnt solve the hum completely and there still was the sensitivity to touching the arm though - my preamp/phono has a floating earth ( ie not a real one no earth pin in the case socket) and I had to make a real one from a mains plug and run that to the tag on the preamp/phono that you connect the turntable earth to, to make a real earth to the preamp/phono. So just a few ideas to try.

In my case the bearing is connected by a metal strip to the arm fixture( under neath - Roksan Xerxes)
Click to expand...

Thanks - will try and digest what his actually means. I am a bit of a technical dunce:)
 
Sounds a lot better too! The 10x5 is staying in for a while :)

Crackles still there when touching stuff, hum a lot better. If anything some electronic noises maybe from the ADAC converter
 
jamington2004 said:
Which Basis do you have? :)

I don't have a SUT but tried both into the phono stage ground

Just swapped out 2m black for DV10x5 - seems a lot better

Hmmm.....
Click to expand...

Signature 2200 with Vector 4 arm,I just paired both wires from the arm and bearing together to SUT with another cable from SUT to Phono,works fine.
 
The hum also gets louder when I touch the finger lift now. Grrrrr

And I think I have replaced standard hum with interference - as it's more poppy clicks digital sounding. New cart has no body/ shell on it which might make sense

Have swapped out phono cables and optical cables in and out of ADAC converter and switch
 
It could be as simple as a broken wire. In the past i have used a length of wire attached to the earth terminal on the phono stage and touched the other end to different parts of the turntable chassis and earth points to find out what's going on.
 
In my case the arm sensitivity was that the preamp/phono had a floating earth ie no earth pin in the case socket - making up a plug with just the earth pin in and a cable to the preamp/phono case ( I used the tag you connect the TT arm to ) solved that. Does your phono have a proper earth?
 
Questions:

I am unclear on how you have everything connected up - where does the bearing ground wire go to?

Have you then got two earth wires running from the turntable to the phono amp?

I am assuming that the turntable power lead has only two wires (L & N, with no earth?)
I am also assuming that the phono amp power lead DOES have an earth connected.
I appreciate a lot of modern moulded plugs might make this difficult to check!

Can you draw a sketch of how all the power, signal and earth wires connect up?

Do you or a friend have a multimeter? - broken earth wire on or from the arm seems a distinct possibility.

You can check continuity (power EVERYTHING OFF!) between arm tube and phono amp earth terminal - with bearing wire temporarily disconnected. Then do the other way around to do bearing earth continuity check
 
You must log in or register to reply here.


advertisement


Back
Top