Project debut carbon dc ground hum

[emcc_3]

Just had my first version of this replaced under guarantee as the first one had a poor ground connection and the left channel would occasionally go completely and be replaced with hum.

New one has been setup and again have a hum, but less pronounced.

Currently have all audio equipment plugged in same strip. Will replacing the extension lead with a surge protector remove the hum?

 

[nopiano]

A surge protector is not the solution to hum, though it might be useful if you fear a flaky power supply or extreme weather events.

It sounds, as much as one can tell from a few words, like you might have a ground loop. Can you try plugging each item in turn into the mains socket directly, or into another extension fed from elsewhere? If that solves it then you need a different wiring setup.

Does your TT have a separate earth lead, and what does removing or connecting it do to the problem?

 

[emcc_3]

Hi,

Yes the turntable has a separate earth wire. If I disconnect at both or one end the hum becomes worse.

Have tried with each component plugged into mains but with no joy.

Only thing I can think is the RCA is the issue or within the tt itself something isn't grounded.

 

[nopiano]

Hi,

Yes the turntable has a separate earth wire. If I disconnect at both or one end the hum becomes worse.

Have tried with each component plugged into mains but with no joy.

Only thing I can think is the RCA is the issue or within the tt itself something isn't grounded.

Is it worse on one channel? If so, swap the cable from the TT so left is right, and see if the buzz moves too. I’m assuming it isn’t just proximity - e.g. the TT right next to, or above, the amp?

The K3 has a proper earth terminal i see, and the amp earthed via the mains, rather then double insulated. Are all three mains wires connected at the mains plug end?

 

[emcc_3]

It's not worse on a particular channel. TT is fairly close to the amp currently but have had it 0.75meters to a meter away previously and had the same hum.

 

[nopiano]

Oh dear. I'm at a bit of a loss to know then. Our friend brownz may be able to suggest something. He works at Henley, the importers.

What does your dealer say?

 

[emcc_3]

Only got the replacement on Thursday so haven't spoken to them yet.

 

[AntAxon]

My Project turntable was working perfectly then one day I got a humming sound from it. Obviously I checked the ground lead but then I found the powerlead had come loose where it plugged in the back of the turntable when it had been moved slightly.

 

[Al ears]

Sounds like you have too many earths. Try plugging turntable into its own power socket and connect earth lead to amp. If it still does it try disconnecting Sonus . The least number of things you have earthed through that mains block the better. If all else fails look at physically disconnecting the earth wire in the turntables mains plug. Good luck.

 

[emcc_3]

Tried the disconnects already. I'm borrowing a other turntable RCA from a friend to try and rule out cable. If that doesn't work will look at your suggestion with regards the earth on the power supply.

It's a pity as the turntable sounds good but the hum becomes a distraction. If there was no hum I would be more than happy with it.

If that doesn't work will push richer sounds for a refund and will look at the rega rp3 or clearaudio concept.

 

[emcc_3]

Checked the plug again. It is built to be multi region as in it is shipped with a 2 prong and 3 prong adapter which clicks into the main psu. Just realised this makes what would usually be the earth pin false.

 

[brownz]

Also - are you sure it's electrical hum ?

With a record on the TT. Remove the drive belt, switch the motor on, lower the stylus into the run in or lead out groove. If your hum appears then, and dissapears when you raise the tonearm then it might be picking up motor hum. Easily fixed by tuning (tightening / loosening) the two screws and two sorabthane mounts that attach the motor to the plinth, or even remove them entirely, each installation can be slightly different depending on what else is in your system or what the mains supply to your house is like . The motor will be fine just sitting on its suspension rubber band.

 

[brownz]

Checked the plug again. It is built to be multi region as in it is shipped with a 2 prong and 3 prong adapter which clicks into the main psu. Just realised this makes what would usually be the earth pin false.

You should have no hum out of the box. It needs to go back to the dealer for us to take a look at if you rule out all other things.
Your ground cable should link to the Phono Stage, and in an ideal world you should have another one from your Phono stage to the AMP.
If your Amp is doulble insulated (two pin cable as per the wall wart with the TT), then adding a Ground Plug can also improve things, but shouldn't be necessary.
(EDIT - Just seen - K3, so you should be fine on that point).
If it does get sent back ask the dealer to send it back for warranty repair and not to swap it for new, and let me know the RMA number so I can keep a look out for it.

 

[emcc_3]

Hi,

I'm using the phono stage on the amp. Ground cable is running between the two.

 

[emcc_3]

Hi,

Hum is there with the motor switched off. I'm guessing that rules out motor hum but happy to have a go if you think it could still be motor hum.

Only other thing I can think of is RF interference.

 

[brownz]

In that case, I'd try another set of cables first. If you're handy with a soldering iron then just flowing a touch of solder into the crimp on the earthing cable can improve matters. If you're not then drop me an email and I'll arrange to get a new cable sent out to try fisrt. If it's still not learnt the words after this, then it will need to come back via the shop for us to take a look at.

 

[emcc_3]

Thanks for this. In contact with richer sounds customer service so will get them to send out a new cable to see if it resolves the issue.

 

[emcc_3]

Thanks for this. In contact with richer sounds customer service so will get them to send out a new cable to see if it resolves the issue.

 

[emcc_3]

Richer sounds are sending a replacement lead.

 

[brownz]

Coolios, let us know how you get on.

 

[MajorFubar]

No one's asked whether the phono input still hums with the cable plugged into the amp but not plugged into the turntable.

Just to manage your expectations slightly, it's unlikely you're ever get the phono input to be totally silent because the pre-amp has to amplify the signal from literally microvolts in some cases, but the noise floor with everything cabled up should at least be lower than the vinyl-roar from a playing record.

 

[emcc_3]

Pardon my ignorance but if the cable is disconnected from the TT but left in the amp what would it suggest if there is still hum?

 

[Nemo]

Pardon my ignorance but if the cable is disconnected from the TT but left in the amp what would it suggest if there is still hum?

A good question, and one I have often pondered. It would suggest its the phono stage in the amp, not the turntable?

(Duck for cover)

 

[Vladimir]

Pardon my ignorance but if the cable is disconnected from the TT but left in the amp what would it suggest if there is still hum?

Faulty cable or possibly near source of interference (lamp, power cord, socket, phone charger etc.). It's usually ground loop or fault cable.

 

[Vladimir]

Pardon my ignorance but if the cable is disconnected from the TT but left in the amp what would it suggest if there is still hum?

A good question, and one I have often pondered. It would suggest its the phono stage in the amp, not the turntable?

(Duck for cover)

If the phono section hums even with nothing plugged in, it's still most likely to be ground loop, nasty energy source, fluorescent lamp etc.