Pro-Ject Carbon Hum

carboniferous
Post Reply
shavermcspud
Great Britain
Posts: 1
Joined: 02 Feb 2019 16:54

Pro-Ject Carbon Hum

Post by shavermcspud » 02 Feb 2019 17:09

Hi all

First post but long time lurker.
Ive had my PJ Carbon TT for a few years and always had the same EMF hum from day one but have lived with it due to low listening volumes.

Ive now got a private listening room so can have the volume slightly higher which has exacerbated the hum.

The kit I have in place.

PJ Carbon Turntable, (doesn't have the external 15v power supply mines direct to UK mains plug.)
Valve Vacuum Tube Phono Preamplifier / Also Pro-Ject MM solid state pre-amp
world audio design valve amplifier rebuilt with UK Mullard valves.
Various high and low end interconnects.

Everything has a common ground from TT, to pre-amp to power amp but I still get hum even without the platter being on. Ive checked and double checked all connections, tried various different interconnects, direct to ground between all kit and power strip, ive tried a new cartridge/stylus and even powering everything off in the house to eliminate.

Even if i unplug the TT from the mains I still get hum.

Ive tried many different cables, pre amps, cartridges and the problem persists.

If i remove the TT from the link by pulling the RCA from the TT the hum goes away.

Ive checked the continuity between the tone-arm ground and the rear ground post and that's fine.

I'm totally at a loss now.

Any help appreciated.

Estragon64
member
member
Posts: 34
Joined: 21 Aug 2015 21:08

Re: Pro-Ject Carbon Hum

Post by Estragon64 » 13 Feb 2019 16:03

I had a similar hum on my Debut Carbon. I was able to cure it by removing the transport screws. You can see the screws here:

http://i.imgur.com/pVSZnpB.jpg

Give it a try if you haven't already.

raphaelmabo
long player
long player
Sweden
Posts: 1830
Joined: 30 Aug 2010 21:01
Location: Askersund, Sweden
Contact:

Re: Pro-Ject Carbon Hum

Post by raphaelmabo » 13 Feb 2019 18:05

Borrow another turntable and see if it has the same problem or not?

vinnn
junior member
junior member
England
Posts: 8
Joined: 10 Feb 2017 12:06

Re: Pro-Ject Carbon Hum

Post by vinnn » 25 Feb 2019 23:19

Estragon64 wrote:
13 Feb 2019 16:03
I had a similar hum on my Debut Carbon. I was able to cure it by removing the transport screws. You can see the screws here:

http://i.imgur.com/pVSZnpB.jpg

Give it a try if you haven't already.
a) OP said...
if i unplug the TT from the mains I still get hum
b) They're not transport screws

Henley
member
member
Great Britain
Posts: 226
Joined: 18 Jul 2011 14:53
Location: Didcot, UK
Contact:

Re: Pro-Ject Carbon Hum

Post by Henley » 26 Mar 2019 14:07

By all means let us have a look at it,. we may be able to add an extra ground track to cure the problem.

Guesstimator
member
member
Posts: 174
Joined: 08 Nov 2014 20:06

Re: Pro-Ject Carbon Hum

Post by Guesstimator » 28 Mar 2019 14:52

I improved things slightly by connecting the bearing housing (from underneath) to the ground post. Also you could try an earthing wire from the TT ground post to the earth plug in the wall.... I never managed to get rid of the hum completely. At one time I posted a video somewhere on here. Just try different combinations and avoid ground loops. I then moved to vintage tt's and I've been hum free ever since. No idea why though...

Post Reply