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

@filipm R16 could have been sacrificed due to a bad tube - which can happen in any tube gear - if that was the case be happy that was the only thing that died.

But - dpop and audiophile1 are correct - this is more of a puzzle than searching for that best sound. The EAR has quite the reputation, but if you just want fantastic sound and not this hassle, you might want to consider an alternate route.

For me, it’s both as I love a good puzzle and great sound. I will add that is seems to be similar for a lot of the folks over at audiokarma dot org - they have quite a few posts on building EAR clones over there, and so far us audiogoner’s here have not been able to solve this. They helped me through a number of puzzles in the past.

Back to your problem. It’s possible you have a combination of a power issue in your place and the EAR is not dealing well with it, potentially due to near failing components. If power is the issue the power company must fix it. But if they cannot, I’ve no personal experience on what you need to do. I would research double-conversion power units - (AC to DC to AC) with a complete separation from the AC power; I believe there some out there are running their audio completely on these things, but I think it has to be complete - no component can be plugged into the wall or your risk a ground loop issue again - so big and expensive. Make sure you can return it if it does not work for you.

On the EAR, given that you had to replace some parts already, best to replace all those electrolytic capacitors as well. I think the EAR came out in the late 90’s, and if this is an original unit, those electrolytic’s in the power supply especially may be near end of life. They are cheap and easy to replace. Just make sure to find units with the same capacitance with same voltage rating or higher and similar dimensions. Nichicon, United Chemicon 105+C caps would be good for the power supply. I would also while you are there reflow all the solder joints on the boards. Takes less time than you think, and that way you are assured there are no bad joints.

When you replaced those film capacitors, did you use new ones of the same capacitance and voltage? The voltage could be higher, but I believe the capacitance value needs to be exact or near exact or it could negatively affect the circuit. For R16, - same - did you use the exact same resistance and wattage value? I think higher wattage would be ok though, especially if the old one burned out for an unknown reason.

One other thing - I noticed the step-up transformers in your EAR - does pressing the MC/MM switch have any effect on the noise with the shorting plugs on? If so that may be your ground issue there - reflow the solder!

@filipm I didn't see that R16 was in the power supply before between the filter caps - should have looked more closely. Not sure what would cause that to fail, but I wouldn't be surprised if it was dirty power (in truth I don't know). In any event, I think that even more supports the thought that you should replace all the electrolytic capacitors in the power supply section and reflow all the solder there as who knows what else would have been affected before the resistor failed.  

@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.