Hum After Cartridge Change + Phonostage

After a few years of running a basic turntable setup (Orbit U-Turn, Yamaha A-S501, Monitor Bronze 2s), I recently installed: 1) a new cartridge (Ortofon 2M Bronze. . .discounted. . . ) and 2) a Pro-Ject Tube Box DS 2.

Now at somewhat high volumes (without a record on), there is a noticeable hum. When I touch one of: the ground on the receiver, the ground on the phonostage, or the tonearm, the hum goes away. When I connect a grounding wire to the receiver or to the phonostage and touch the other end, the hum goes away, but only when my hand is near or behind the equipment. When my hand is in front of the equipment, the hum is a little quieter, but still very noticeable. When I connect the ground wire from the phonostage to the receiver, the hum is still there.

When the phonostage is unplugged, the hum is still there a little, but not nearly as much as with the phonostage; and when I touch the tonearm, the hum goes away.

In any scenario, if I touch a screw near the bearing of the tonearm or touch 2 of the wires from the cartridge, the hum gets much worse.

I connected my old cartridge (Ortofon 2M Blue) and the humming is the same.

None of the components have a ground wire in the power cord, and the turntable is internally grounded.

My current theory is that I messed up something with the tonearm wiring when I changed the cartridge and the phonostage is amplifying that. I was careful when changing the cartridge, but I did need to pull a little hard on one or two pins. But I'm not sure that would explain why the hum goes away when I touch the tonearm/ground screws.

Does this actually sound like a grounding issue? If yes, how I can properly ground the equipment?

 

Check the ground wire is tight. When I changed table, I didn't connect the ground wire properly and it hummed until I realised.

If its not that, I'm sure someone else can suggest something.

 

I have the same phono stage and a similar problem, not a hum, rather a buzz. I think it is caused by the high "sensitivity" of the phono stage to other appliances emissions, like modem, tv set or even an air conditioner. I had the same buzzing with a Clearaudio phono stage, and in the manual, customers were warned that due to the high sensitivity of the phono stage, it could pick up high frequencies coming from other appliances. Shielding the phono stage would lead to a worsening of the musical performance. In my set up the buzzing is perceivable starting from volume at 12 hours position.

 

Any phono stage can be sensitive to placement and sources of outside interference - some more than others. Cables with good shielding help, as do the designer accounting for potential interference. However, there are some things that don't mix well at all with turntable systems and you need to get those things completely off the same circuit and far away from the phono stage as possible if you want to avoid problems like that.

 

Thanks, everyone. I get the sensitivity and shielding aspects. But when I touch the ground screw with my finger, the hum stops. If the hum was because of a placement or shielding issue, wouldn’t the hum persist even if I touched the ground screw?

 

Paging @SeeDeeFirth

 

Hmm, that sounds more like a grounding problem.

 

Certainly does.
Happens with electric guitars too.

 

Right

That’s what I figured. What I’ve tried is to attach a grounding wire to the phonostage ground screw. When I touch that when the wire is behind the equipment the hum stops. But when I touch it to a screw on the turntable or receiver, there’s no impact.

Any suggestions for how to ground it properly?

 

If I recollect correctly U-Turn's support team sent out a ground connection cable (plug it into a power outlet) to solve this issue for another member here.
Contact them.

 

You are right, I think my problem is caused by telephone cables conducting adsl signal, that share the same conduit, I don't know if it is the correct definition, with power cables of my home

 

Yeah, that might be it. Some guy on here recently had an issue with powerline ethernet - problem disappeared when he disconnected that system. Awhile back another guy had an issue with a deep freezer in the garage. Supposedly smart fridges can cause problems too.

 

I think you would be shocked at the noise the modem makes talking on WAN.
I am a telecoms engineer, and sometimes have to listen in on phone circuits to listen to general line noise.

 

Powerline ethernet is evil stuff - ask Graham Slee about it.
They work by modulating signal over the AC mains, and in plain speak it's RFI.

 

Excuse me, what means WAN?

 

I had a similar problem with my perreaux phono stage. I ran a second wire with bulldog clip back from the phono stage ground to the base of the mounting plate for my tonearm (same effect as touching it) and basically regrounded it. Fixed the problem completely. Think it was a ground loop problem from other equipment.

 

Wide Area Network, in other words your ISP gateway.

 

Thanks

 

RFI I can't stand. It's the devil incarnate I tell you!

 

It's why I fitted ferrite clamps on just about everything electrical in the house.
They're simple low pass filters, and let stuff below 150 KHz through unhindered.

 

Thanks, I’ll do that.

 

Update on this: U-turn sent (for free) a ground cable that connected to the white RCA connector on one end and to an outlet on the other. That pretty much solved the issue. Then I grounded the DS 2 as well, and I now can't hear any hum at all.

 

Have you checked your cartridge is attached sufficiently tightly to your headshell? You might need a ceramic Or otherwise non ferrous screwdriver to ensure this if your cartridge is MC

 

Seems pretty tight to me. What would I be hearing if the cartridge was too loose in the headshell?