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

I just noticed this:

>>>solid stages (I had 3, they were ok)<<<

So to be 100% sure, in your current high RFI/EMI environment, using a SS phono stage (the CP60) produces no noise? Is that correct?

>>>I measured 33 ohms between the grounding pin on the chassis and the grounding pin of the inlet.<<<

If the piece of equipment you're referring to is the EAR, that figure should be much closer to zero ohms. If you were measuring the resistance of a wire that was maybe 100 feet in length, sure, maybe *that* figure could be 33 ohms, but it shouldn't be when measuring a connection the distance of inches, especially a ground connection.    

>>>So I took the EAR to my friend's place. Horrible wiring, cheap components - absolutely quiet and great sounding.<<<

I'd be curious in knowing if his system has the same meshing of XLR and RCA equipment as yours does, or is his exclusively RCA unbalanced connected equipment?

@filipm Looking at that above linked picture, I can now see (rather clearly) what the little silver screw on the back does. As you mentioned Filip, it supports a shield - a shield that isolates the audio portion of the EAR, from the power supply portion.

As an A-B test, is there any noise difference when completely bypassing the EAR (pretending for a moment it doesn't even exist), and feeding the turntable (TT) directly into the ARC LS16 mk1 TT input (I realize the Bryston B60 does not have a TT input)? If the noise still exists, does it still exist when trying a different set of RCA cables (feeding the ARC LS16 mk1) ? I apologize if these questions/suggestions have already been put forth.

This is definitely a fascinating post (at least for me), with so much detail explored. The greatest thing that was accomplished right off the bat was the fact that the OP (filipm) was able to record and post the noise or interference that he is experiencing and hearing. When trying to troubleshoot noise and interference, *that* is worth gold all by itself. With so many suggestions already being offered and tried, I'm not sure I have anything left in my arsenal to propose. I'm going to go back over all of the tips and suggestions, and see if I can offer anything. This is definitely one of the worst cases of noise (RFI & EMI) that I've ever heard. So far, it looks like finding a fix for this particular setup is quite the challenge. I completely understand your frustration filipm, but admire your tenacity.  

Sorry, I didn't realize that the LS16 didn't have an internal TT preamp. Is there any TT noise when going into the CP60's TT input (using the existing RCA cables that you're using with the EAR setup)?

So to be 100% sure, in your current high RFI/EMI environment, using a SS phono stage (the CP60) produces no noise? Is that correct?

...when using the exact RCA cables you were using when hooking up the EAR?

>>>very late at night or very early morning, do you still have this noise? If not, then I’d suspect someone in your building is the culprit.<<<

I was just wondering if this question was ever answered? Is the noise consistent at all times of day or night?

Do you have any other phono cartridge (already mounted in a headshell) besides your Nagaoka MP200? If you do, does the noise change (in any way) when using a different phono cartridge?

I'm not sure you answered my question though; in your current living space, with the problems you're now encountering with the EAR turntable preamp, what happens to turntable noise when you plug your turntable directly into the AR preamp's turntable inputs? Is there any difference comparing that wiring connecting setup, to the noise encountered with the turntable plugged into the EAR (and then routed to the AR preamp)? I understand that with the RCA cables in the baking pot, noise has been reduced. I'm also wondering if shielding (design, or lack there of) on the Nagaoka MP200 is part of the problem here, along with RCA cable shielding. I completely understand that you want to continue using the EAR, but I'd still be interested in knowing if noise is reduced (and by how much) when going directly into the AR with the turntable. Just curious.      

It also sounds like you purchased the EAR used, and I'm wondering if anyone has made some internal modifications along the way. 

You have a very unique setup, where you're mixing balanced (XLR type) and unbalanced (RCA type) pieces of equipment together, and in a situation like that, they don't always want to play nicely. This is when ground loops can take place. 

Are you familiar with a ground lifter plug? I know we have them in the US, but I don't know if you have them there. I'd be interested in hearing what the EAR would sound like, if you lifted the AC ground to it, while still keeping the TT ground connected to the EAR. 

So to be 100% sure Filip, while in your apartment, using a SS phono stage (for example, the CP60), and the turntable connected *to the* CP60, the noise goes completely away? Is that correct?  

if so, I kind of agree with audphile1: At this point, the cure is worse than the disease. Dump this phono pre-amp and get one that’s properly designed to not be susceptible to this type of interference, at least within your setup (or simply use the CP60's TT preamp, if that is quiet). Seriously. You’re going to drive yourself nucking futs.

It's almost guaranteed that spending lots of money on parts (different RCA cables, ferrite cores, heavily shielded AC cables, new tubes, tube shields, etc.) is not going to fix this EAR issue. It's either a grounding problem (which I can't seem to diagnose via this thread), or it's an EAR design issue (the EAR can't filter and repel the high amount of interference in your apartment). You also mention that some components have already been replaced in the EAR. I'm wondering why they failed in the first place? That's not typical of (and very rare IMO), of audio gear, and in a way, sends up an immediate red flag for me.  

@ejb14 Hmmm, you just made me think of something. It's possible the chasis is floating (no earth ground connection). Filip, do you see that little silver philips screw on the back panel with the bonding washer (washer with ridges which digs into the panel when screwed down) underneath it? Is there any wire connected to it inside the EAR? 

@filipm I'm looking at one version of the schematic on line...

https://rockgrotto.proboards.com/thread/11529/ear-834p-phono-stage-mods

...and it looks like the earth ground (e) is actually part of the audio circuit. Wow, I've never seen anything like that before. I would think this design makes it super susceptible to picking up atmospheric electrical noise. I don't care how good it sounds, this is a piece of equipment I would personally (and maybe you should too Filip) not incorporate into my audio system. IMO, it's a very poor design, but, I can see you're more than determined to keep using it, and make it work in your electrically noisy environment, so, I'll give it another try...

To fix this would probably entail a complete do-over (let's eliminate that option right now). From looking at this schematic (if this on-line schematic is a true version of *your* model), it looks like anytime you plug this EAR into a grounded outlet, the entire ground system that it's plugged into becomes part of the audio circuit (I hate to think of what this thing would sound like in a high RFI radio station environment, which already has loads of RFI and EMI in the surrounding atmosphere). 

My first suggestion is to (however you can accomplish it) lift the "e" ground at the chasis iec connector (I hope you know how to solder). It has to be done there, and nowhere else. Now how does the unit sound (with the turntable ground connected to the EAR where it should be)? If that still produces noise, I would reconnect the "e" ground, and purchase an Isolation Transformer, like this one:

XtremPro Hi-end Ground Loop Noise Isolator

Connect the XtremPro (since it probably employs a transformer of some type in its design, I don't know how perfectly flat its frequency response is) between the output of the EAR, and your preamp input (while still connecting the TT ground at the ear). How does the EAR sound now? The XtremPro should (hopefully) break the ground loop that's taking place with the design of the EAR. If that works, if needed, you can always shop around for a higher quality RCA isolator. Good luck.  

@oldrooney ...but has the problem really been resolved? We haven't heard from @filipm for a few days now. 

@filipm Thanks for the reply Filip. Looking at the pictures you have provided so far proves to me that the chasis is *not* floating (from earth ground), as I can see the green earth ground wire is soldered directly to the rear panel banana standoff/TT ground connection screw thread. That was one thing I was questioning. I still *highly recommend* purchasing this isolation transformer from Amazon. 

XtremPro Hi-end Ground Loop Noise Isolator/Filter 

It's pretty cheap, and it's always nice to have one of these in anyone's bag of tricks, when hooking up audio pieces of equipment. Again, if you do purchase this, it gets inserted between the TT preamp output, and the preamp input the TT preamp is feeding. 

@filipm Unfortunately, I don't have the engineering and design knowledge that's required to explain why that's in the circuit. Looking at the resistor, at this point in time, if you wanted to re-insert it back into the circuit, it's going to be impossible to do that, with the lead now clipped right at the resistor. I'm not sure I would have removed it, as you say the EAR plays fine anywhere else you use it, besides when used with *your* system. That means you have a problem that's exclusive to *just your* setup.  

It sure looks like the resistor is in place on *this* particular unit:

picture of resistor