Turntable grounding issue (I think?)

BuToNz

BuToNz

BuToNz

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Hi guys,

Wondering if I could get some help...

Purchased a Pro-Ject Debut Carbon DC + Pro-Ject Phono Box Mk2. All setup and working ok but I'm getting a dreadful hum at any kind of volume.

The connections are as below:
F2kvHcH.png

Two things to note: My AVR/AMP does not have a phono preamp (Hence buying the Phono Box) nor does it seem to have any grounding termination point. Secondly due to space issues the turntable is around 5 meters away from the AVR which also requires it to be on a different wall socket. Not sure if this makes a difference.

Disconnecting the grounding wire between the turntable and preamp worsens the humming/buzzing. My understanding is I have issues with ground as nothing actually has a set ground?

Any advice appreciated - It's a struggle to find anything through Google as it seems most people don't tend to use an AVR as the amplifier.

Many thanks!

***SOLVED - ISSUE WITH RCA SUPPLIED WITH TURNTABLE***
 
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You've probably done this, but check to make sure all the connections are correct and properly seated and that the cartridge is wired correctly.

Does your tonearm have a detachable cable? If so make sure sure it is properly seated as I once had an awful hum caused because it was not fully inserted..
 
marl said:
You've probably done this, but check to make sure all the connections are correct and properly seated and that the cartridge is wired correctly.

Does your tonearm have a detachable cable? If so make sure sure it is properly seated as I once had an awful hum caused because it was not fully inserted..
Click to expand...

Done all of this, doesn't seem to change the noise. :(

Additional info which I think (After some reading) is pretty important:

Connected to my AVR/AMP is my computer via HDMI (in) and my TV via HDMI (out). Unplugging the computer from the wall increases the noise, so I assume some sort of grounding is being done through my computer?

My computer/TV/AVR-AMP are all connected to the same surge protector. As previously stated the Turntable and Preamp are both connected to a different wall socket. However I have tried connecting them to the same surge protector as the computer/TV/AVR-AMP but the hum is still there.

Quite confused now, I assume the only thing which has a ground is the computer? :confused:

:EDIT: Just thought actually...The subwoofer from my cinema kit is connected via figure of 8 (2 pin) to the same surge protector as the computer/TV/AVR-AMP. This does not hum or have any issues.

***UPDATED ORIGINAL POST WITH BETTER DIAGRAM***
 
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Try unplugging the other inputs/outputs from the AVR and see if any of the others affect the issue. (up to the point where only the phonobox is connected) If it is limited to the phonobox only, you could try a ground loop isolator between the phonobox and the AVR.
 
Kei said:
Try unplugging the other inputs/outputs from the AVR and see if any of the others affect the issue. (up to the point where only the phonobox is connected) If it is limited to the phonobox only, you could try a ground loop isolator between the phonobox and the AVR.
Click to expand...

FerretBoy said:
Indeed remover everything from the amp and add one at a time until you get humming.
Click to expand...

Thanks guys, I'll pull the lot out tomorrow and give it a bash. Will adding a ground loop isolator effect sound quality at all?

kitfit1 said:
This is a well documented issue with this deck. It might well be worth having a good read of the link below.

http://www.avsforum.com/forum/173-2-channel-audio/1513521-eliminating-hum-pro-ject-debut-carbon-turntable.html
Click to expand...

I don't think this is the same issue as I'm having. The hum is there no matter the turntable power status. I'll have a good read though, thanks.
 
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Wow, so...tried a new set of RCA's between the preamp and turntable. All hum/buzzing gone. Can't believe with a £300+ turntable they couldn't include some half decent RCA's. I guess the included ones aren't shielded?
 
BuToNz said:
Wow, so...tried a new set of RCA's between the preamp and turntable. All hum/buzzing gone. Can't believe with a £300+ turntable they couldn't include some half decent RCA's. I guess the included ones aren't shielded?
Click to expand...

Were they supplied by the retailer, or were they supplied by Project with the turntable ? Either way i have to agree with you, supplying leads that induce hum is just about as stupid a thing i have heard.
 
They came with the turntable, they look decent and seemed to connect snug but obviously very poorly shielded!

Semi-decent RCA's being used now and zero hum/buzz. Don't know why they even bothered to include them.
 
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