Tube PHONO preamp interference - RFI, EMI, bad grounding?

@ejb14 We'll see what we can find on the AC line but I wouldn't be surprised. I am already looking at some power plants. Not sure if PS Audio is the way to go, I have been told by ARC that they recommend plugging their power amps directly to the wall otherwise I'll end up with limited dynamics. Other people say their system sounds better with a PP without any restrictions in the dynamics. Haven't tried any filter, nothing. 

I'll check what the capacitors say, a friend of mine has replaced them for me. I still have a picture of the old ones. 

The step-up transformer - yes, the noise level is different. the opposite I'd expect actually. I have a MM cartridge and the noise is stronger when the EAR is set on MM. There should be higher gain with MC settings but the noise is less audible, significantly. But it's still there for sure - and it would also be audible during playback.

I have talked to a guy who builds tube amps, a local. He's willing to take a look at the REF150 and I will take the EAR along. If he won't find a problem, I'll sell the EAR. It's gonna be a bit weird if someone comes to listen to it though :) 

@dpop 

The 33 ohm resistance can be there to avoid a ground loop, as I was told by people who build tube gear. 

You're right, I won't linger on it. I'll let one more person to see the preamp and if he says it's fine, I'll sell it. If not, we'll try to repair it.

I found the answer from the EAR factory - 

It's difficult to say but I suspect a broken earth connection to the screening of the input cable or possibly a broken earth connection on the 834P itself.

This would account for the lower noise level when touching the cable where the user's hand would give some grounding effect. 

Does the noise go if all input cables are disconnected from the 834P ? 

Be careful with adding additional earths as this may create an earth loop and introduce hum noise. The other possibility is a poor earth on the 834P metal top cover. This should be grounded via the four fixing screws. if this is not grounded it will pick up all sorts of external noise.. 

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I'd like to try PH5 phono stage but it's a real hunt in Europe. All the ARC preamps are always gone really quickly. 

OP,

My condolences on your plight. In hearing your first recording, my reaction is that is digital… digital signals sound like that.

As for the ARC amp… I assume you tried plugging into the power conditioner. It doesn’t sound like a ground loop. But if all components are plugged into the same circuit, that is eliminated.

On the ARC amp. Can you use an insulator and push on it and stop the buzz?

Good luck. I would borrow components (even cheap ones) and swap them out… to identify to verify it is the EAR. Then just swap it out. Sorry to hear of your predicament.
 

@filipm ok - sounds like a plan. Good luck to you!

FYI - one last thing - that 33 ohm value you found between the phono shields and the chassis on the EAR does not sound right - all the phono stages I have have negligible values (0.1 ohms) like your REF150 between shields and chassis and ground. I looked up the schematic of the EAR and suspiciously R16 is a 33 ohm resistor, and more suspiciously R16 was recently replaced. I am not an expert, but in the schematic it doesn't look like it supposed to be attached to ground. I'd recheck that one.

That noise to me sounds like something is generating on the building AC power service line or on the apartment circuit. I would like to see what's else is on the same circuit. Sounds like a motor driven fan or compressor and even a celling fan or something turning. "Maybe even the buildings boiler room generator or vibrating power massage chair"!

The vibrating chair was only for humor but something is oscillating on this circuit...

Bill M