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Turntable ground

Kinda strange, I have the technics slq3 table when I connect the ground I have slight hum, not bad enough to interfere with music. However when ground was left floating, dead quiet. 

pureclarity
yogiboy's avatar
yogiboy
6,193 posts
 

If your table is quiet with no ground wire why bother with it?

Direct drive turntables: Some models require grounding, while others (especially newer ones) may not 

pureclarity OP
95 posts
 

@yogiboy exactly what I did. Left it off and enjoying the music Connecting it probably created a ground loop somewhere.

stager
83 posts
 
stager
81 posts
 
 

In any audio circuit there are two ground paths: chassis ground and signal ground. In a balanced system these two ground paths run independently, hence the 3 pin XLR connector.

In an unbalanced system, aka the typical home stereo system, the two grounds are combines at the shield of the RCA connectors.

If your preamp and peripherals are also grounded with a three prong AC plug, you are running two ground paths at the same time, often causing a ground loop and raising your noise level.

Best practice: 
Plug your highest current drawing component, generally your power or integrated amplifier, into the wall outlet with its three prong AC plug. Lift the grounds for all the other components so you do create a ground loop. This will be perfectly safe - the grounds are passing through the unbalanced RCA audio cables and nowhere else.

As for your turntable: Your cartridge and turntable are a balanced system and for the quietest operation, the chassis grounds should be connected between turntable and preamp chassis - that’s why there’s a ground screw.
The RCA cables from the turntable cartridge constitutes the signal and signal ground from your cartridge. They will merge with the chassis ground at the preamp.

If you have lifted your peripherals’ chassis grounds (by not connecting the ground in on your AC plug except at the power amp), then your turntable ground chassis ground link will work properly and you will get the lowest possible noise your equipment allows.

However:
It's possible your Technics TT grounds are internally linked - there should be no continuity between the ground strap and the shield at either of the RCA connector at the TT's interconnect cable.
If there is, they they are linked, and it makes sense that you eliminated the noise by cutting the ground loop from a redundant chassis ground cable. In that case, just leave it off and put on some music.

This is NOT the way this is usually done.

refs:
https://www.perplexity.ai/search/e8cf6fe1-e90e-4201-8dca-ad093a2b6686

And have a look at these remarkable audio cables, the most transparent and accurate interconnects on the market:
https://silversolids.com/

atmasphere's avatar
atmasphere
12,412 posts
 

I also replaced my hardwired rca cables and put in rca jacks on the table and upgraded rca cables. At the same time updated the ground wire, but as mentioned above there is no hum when ground is disconnected.

@pureclarity Nearly all turntables are balanced sources which are being operated single-ended. That is why there is that ground wire that no other single-ended source seems to need.

When you replaced your jacks and cables, something got mis-wired. Its worth finding out what, since the sound (independantly of hum or buzz) can be improved. 

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