Phono lead earth help (cable experts)


#1

I’ve just taken possession of Crimson Donkey’s plinth and arm set up to demo.
Lots of hum.

I noticed the earth cables he had were:

  1. from the arm to the phono stage :heavy_check_mark:

  2. a loop of wire that was doing nothing at all (ring that was earthed for no reason). :heavy_multiplication_x:

Looking at the SME manual this second wire should be two wires that are connected to the RCA at the phono stage end and then earthed together as a second connection.

My problem… how do I connect an earth to the metal rca? Is it just wire to the wire outer? Or do I have to undo the plugs and factor the earth in intenally?


#2

You can see the wires from the rca to a second spade.


#3

This wire needs to be connected to these plugs. It’s missing and I suspect this is my issue!?


#4

Put it on the Paradise earth tag, if its still humming does the amp have a tag, try it on there.

At the arm end, SME’s often have another tag to connect to the TT chassis, either connect it, or un-connect it depending where its at. Earth loops are a bit of trial and error.


#5

It’s the fact the metal rca should have an earth on each. As per the first picture and this one.
You can see the right hand side outputs have earth wires running out too.

I have the arm to paradise tag attached. I need a second earth fixing to the metal rca as below (you can see the earth wires exiting both plugs).

My ONLY question is: how do I connect the ground wire to the plug? Is just touching any of the metal outer sufficient?


#6

Try a croc clip and see if it cuts the hum


#7

Or just hold it against the metal of the rca to test


#8

Does touching the loose wire to the tag quieten it down? I’ll bet not?

The Paradise earth tag is connected internally to the earth of the phono plugs so extra wires won’t make a difference.

Also try with a standard lead + a bit of wire trying different combinations till its quiet.

While I don’t agree with Rega’s philosophy of no separate earth, having multiple tags doesn’t alway help either.


#9

Can’t get rid of the hum. Tried taping wire on the rca outer and earring both.
The power supply switch for the SP10 is now tripping the amp.
All gone wrong.


#10

Bugger, is the other deck ok?


#11

Frustrating this. It wasn’t consistent level of hum either. At first we thought it was the proximity of the SP10s PSU to the Paradise phono, as moving the psu initially killed the hum.

Never had this issue at mine, nor at Jim’s in January when we used it in the back room. :man_shrugging:t3:


#12

The psu is still tripping it. I think I need to check it.
But it hums without the power to the motor unit at all. I added another ground to the SME binding post (was just the deck earthed) but that’s ineffective.
Plan B is connect up the other arm and plinth and see if it gets rid of the hum. If so, the SME cable is the issue maybe.

Maybe it’s this issue

The bad ground and my paradise being a lot more sensitive?


#13

Have you tried CD’s ?


#14

You need tape faff. It might be less faffy.


#15

Earth hum from turntables, arms, SUT’s, phono stages.

LOL, black art.

Throw the instruction manual in the bin and just try stuff :smile:


#16

Haha, up yours science!


#17

Seriously, it’s a minefield. Science could probably explain it, I’m sure, but trial and error is faster.


#18

I’m yet to experience it. I’m accumulating all the bits but ran out of money :roll_eyes:

Hopefully I don’t smash it all with a hammer once I’m there.


#19

Don’t get me wrong, mostly it just works, It’s only when you get that mmmmmmmmmmmmmmmmmmm that you have to piss about.

It’s no big deal, you’ll get there in the end.


#20

Earth the tt.