 ![]() @lewm I think what I have done with the baking pot proves that I'd have to use a sleeve for the cables as well. I have used 20 feet XLR cables to reach the other side of the room, closer to the router. Then I placed the router right next to the phono stage and put the phono preamp and the cables inside. Problem solved. Except it's not the most practical solution. :) The pot wasn't grounded but most of the cables must be inside. Once they pop out, they pick up the interference.
There's actually a hint - even the output cables react to the interference. When I squeeze them, the noise changes.
Let's see what an aluminum foil on the tubes does..
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When you squeeze them, you create a ground via your body. I have a table radio in my kitchen. It reacts to the lighting over our sink, which is on the same circuit, and also to a Canary detector plugged into the same outlet. If I hold the radio antenna in my hand, the RFI noise over the radio gets much quieter. The EAR is not balanced, is it? Looks like you have an ARC linestage sitting on the floor; is that unit internally balanced? I presume the 834P is inside the green thing.
Incidentally, maybe you wrote in haste, but I would not encase individual tubes in foil. Bad for cooling. That's the beauty of well designed high quality tube shields; they draw heat away from the tube and actually extend tube life, besides blocking interference. If you’re going to use foil, I would suggest just wrapping the whole chassis in foil; of course, you will eventually have to figure out how to allow for the whole device to stay cool, unless you install shields.
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Can I ask what you are using the Chord Qutest for?
I had an issue like this caused by a streamer.
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@filipm
From your experiment, the cables might be more an issue than the EAR.
Try some Gotham Audio Double Reussen shielded interconnects - TT to phono and phono to ARC. - fairly cheap, but good quality and very good shielding, much better than many audiophile cables.
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+1 on the Gotham interconnects. They are very good and can be bought directly from the manufacturer on line at a very reasonable price.
The best tube shield by far IMO is the IERC. They have ”fingers” inside that connect to the tube, reducing microphonics and leading away heat.
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@lewm That’s for sure - I’d only wrap the tubes or the unit into the foil for about a minute. It takes a while, about ten minutes before the tubes are warmed up. Sonically even longer, the real listening with the EAR starts after half an hour and then it’s just getting better.
Yes, that’s an ARC LS16 mk1. It’s balanced, I’m using Nordost Red dawn XLR cables. There are different cables on the picture, balanced as well, about 20 feet long - I was trying to move it on the other side of the room to see if the noise changes.
EAR 834p isn’t balanced.
I have tested the EAR with several components, Bryston B60 for example - same results.
@dover Thanks for the tip but is the issue is shielding, I’d rather just add shielding to any cable than testing different brands. That could get quite expensive. If it proves to be the shielding then I’d gladly buy one of these cables.
A simple shielding test could be again the aluminum foil. I have tried this before and it kind of worked but the noise didn’t disappear completely. The shield should be grounded, right? Maybe a piece of wire between the shield and the ARC preamp?
It would be the best to share the recording of the noise on some radiophonics forum. The sound is very specific so eventually I could find the source.. or am I being naive? I have tried googling things like "wifi noise" etc.
If there’s about 4 to 6 wifi networks, they may be overlaping.
A sound sample at 1:00"
@plumptonvinyl The Chord Qutest is connected to a streamer right now. I’m using a Allo Shanti linear power supply with it and it sounds very good. My streamer is a Raspberry Pi plugged into the router with an ethernet cable. I haven’t got the soundcard for it yet but I will upgrade it soon. It’s also powered from the Allo Shanti. I have had this problem before I bought the streamer
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From all the tests you have done, and the results, I believe that your noise is RF interference entering through your inputs and being amplified by the Ear as though it were an audio signal. I suggest getting some shorting plugs (cheap on Amazon) to verify this - just get two of those and connect them at the inputs (not the outputs!). Then listen to the amp. I suspect you will then have no noise at all (which is as it should be). If you have no noise, then that is how the sound is coming to the amp - not through the tubes, or the power, etc. The fact that you do not hear this noise when not in your apartment, and the fact that the noise reduces when you grab the cables makes me think this.
Some equipment used to come with shorting plugs way back when (my old Luxman R1050 had two phono inputs which came with these as they (shock!) amplified noise from my wifi router when not in use.
If this experiment has no noise, then not sure what you can do - either get rid of the source generating the RF (hard to do if it is not in your apartment), or perhaps the Ear has an RF filter (ceramic capacitor or an RF choke) on the input and it has failed. I seem to recall my old NAD preamps had these soldered inside on the inputs for this very purpose. The Ear may not have this at all, but it would be good to pop the lid and check - your Ear may have some kind of input filter and they have failed or their solder joints have failed and they are longer connected to ground?
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@ejb14
Ok, I'll get them as fast as possible. I actually got this recommendation a while ago but I have been trying so many things I have forgotten. Thank you.
I have tried to find out how the wifi noise sounds like. Are you able to record it? Is it any similiar to what I have posted? (the noise sample on the top of this thread)
If the stoppers help, I'm thinking the RCA cables would have to be placed in a copper sleeve, maybe even two copper sleeves. I'd solder a grounding cable to the sleeves and ground it to either the phono preamp or to a screw on the ARC linestage.
(I'm only suggesting this from my previous experiment with an aluminum foil - I had wrapped the input cables in several layers of the foil. The result wasn't perfect but it was ok just to see how the phono stage actually sounds in my setup.)
I'll also borrow some cheap integrated amp and a small speaker. There's a socket on the first floor of my apartment building so I'll test it on the hallway. If it won't pick up the noise then I'll do the same on the top floor. That should give me a hint where it's coming from.
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Just to be sure - sometimes "stopper" will not have a signal pin (like the AudiioQuest stopper is just an RCA cover with no center pin), but for this test you want shorting plugs with the center pin. You want the signal shorted to the ground so there is no signal on the input (which is also why I said don't put them on the outputs - they will blow the amp on the outputs).
I no longer have the luxman, and not sure if my current preamp is susceptible -(solid state Sutherland PH3D). I will see if I can try something.
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@filipm
I go back to my original statement. Flawed design or broken. It should not due this. If this happens on both channels, then it is a flawed design. A small capacitor between the signal input and signal ground (or case ground) and the noise will probably disappear. Cables may make a difference .... or not.
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Aluminum foil is fine for identifying the source of radiation but if it works you’ll need a more practical long term solution, like possibly tube shields or other.
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At this point the cure is worst than the disease. Dump this phono amp and get one that’s properly designed to not be susceptible to this type of interference at least within your setup. Seriously. You’re going to drive yourself nucking futs.
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This is not an inherent fault of the 834P. Shorting the unused inputs is a good idea.
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It absolutely is an inherent fault of the 834P @lewm . No quality piece of equipment should be that susceptible to RFI. It is broken or poorly designed. If other phono-pre don't do it and this one does, that is all the clue you need for that. That it uses tubes is no excuse.
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@filipm ,
The dominant signal in the recordings you posted is 50Hz. It is much larger than any other frequency component. I don't know if that is due to noise in your system, the recording, or it is a demodulated frequency from the noise you are experiencing.
The bursts are a packet rate of what looks like 2KHz, which is close to what you would get from GSM, but not close enough. (1.7KHz versus 2KHz). It is bang on 2KHz.
Maybe there is a wickedly noisy power supply in your vicinity and the RFI in in the building wiring.
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Although I don’t recommend tube rolling in order to improve sound quality, in this case it might be worthwhile to change all the tubes in the unit. It could be that one or more tubes is defective, thereby enhancing susceptibility to the noise. Even if that did not help, there is also the possibility that there is a cold solder joint somewhere in the chassis, possibly in a connection to a tube socket. So I would try the inexpensive and simple things first like shorting the unused inputs, and shielding the unit, and shielding the cables, but if that does not work you might want to take it to a knowledgeable technician who can measure the voltages.
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@theaudioamp thanks, this is nice. 50hz means a ground loop, right?
the system is overall quiet with the other inputs. there's only slight white noise on the DAC's input, audible only when I'm really close to a speaker and at high volume levels.
If it was in the building wiring the noise would be gone with that battery we have tried here.
@lewm I'll have a different set of tubes next week. It's gonna take a while to get the shorting plugs.
I still think the EAR preamp is not defective simply because it works well anywhere else I have taken it. This must be an issue of the location. Soon I'll bring a simple integrated and plug it in in the hallway two floors lower.
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@filipm ,
I am suggesting that your phono stage is picking up RF that is being radiated through the building wiring. using the inverter would not change that. Though I assume that your turntable was unplugged from the AC and/or unplugged from your phono stage when you did that test.
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@theaudioamp That's possible but the noise if being picked up even when the turntable was unplugged from everything. The signal was just weaker. I can plug any RCA cable to the input of the phono stage to get back the strength of the signal, doesn't matter if the turntable is plugged in on the other side. That's the most confusing.
I'll know more next week though. Different tubes, I'll do tests around the building with more practical intergrated amp (I'm using separates) and I'll have the two closest neighbors' wifi switched off.
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@filipm , an underlying 50Hz, with a 2KHz packet rate is not WiFi. WiFi is rarely an issue with interference into low frequency analog electronics. The 2.4GHz signal is fast enough that most "things" cannot demodulate the frequency, and the modulation method also helps. I strongly suspect it is something else, though it could be 2 somethings, the 50Hz from building wiring, and the 2Khz from something else. Some home automation could be close enough to a 2KHz tone.
@filipm can you please do the following if you have a multimeter. Measure the resistance from the signal ground on the Phono input to the metal case of the box.
CABLES: I don’t know all the cables you tried, but you don’t need BS marketing crap like how the AQ Mackenzie is described. You need good old fashioned doubled shielded coax. Ignore all the marketing crap and use something that is designed using proper engineering principles like the Blue Jean LC-1. https://www.bluejeanscable.com/store/audio/LC1-design-notes.htm A cheap $10.00 coaxial 75 ohm video cable is likely to work better than that AQ crap for rejecting RF noise.
If adding the RCA cable (without the turntable) brings back the noise completely that tells me that your probably not using coax and/or (could be both), there is no connection from the signal ground to the metal enclosure. There should be a connection, at least capacitive between the two, so that the "cage" is unbroken and so that the potential (voltage) between the two is the same at RF frequencies so that no noise can transfer between the two.
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@filipm
Although I agree with most of what @theaudioamp has suggested, I'm yet to be convinced this is actually the fault of the phono section, even though the phono section is clearly able to amplify the noise.
First off the 12AX7s have nothing to do with this. They are not somehow inherently sensitive to RFI. How their grid circuits are set up is an entirely different matter...
The length and exposure of the 20 foot XLR cables is a clue.
I think that what is happening is there is noise being picked up and injected into the ground of the ARC (which plays the same sound at a much lower level...). Since the ARC does not support the balanced standard (even though otherwise is balanced) a noise is manifest.
To sort out what is going on first short the inputs of the phono section to be sure its OK. Removing the top cover and no additional noise points to the idea that the phono section really isn't the culprit. But if shorting the phono inputs shuts it up then the phono section needs mods to protect it from demodulating RF (demodulation is what causes nearly all RFI problems). I've seen this sort of thing caused by poor tonearm cables too, but if the phono section is adequately protected from RFI its usually no concern.
If shorting the inputs has no effect I would be trying to use different interconnect cables. A lot of 'high end audio' manufacturers have a poor grasp of how balanced line is supposed to work so I would be trying a cheap microphone cable like you can get at Guitar Center since such a cable will be wired correctly and will also have an effective shield. Note that this cable is between the preamp and amp; the idea here is that noise is being injected elsewhere from the phono section but is able to be amplified by the phono section; the noise is in the grounds of the preamp and is being passed to the phono section.
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@atmasphere Thanks for the long answer. First of all, I totally agree it could be a matter of poor wiring (Even though I have tried the same TT and cables elsewhere and it was fine). But it can’t be the XLR part.
Is there a way to short the inputs without the input shorting plugs? (I have ordered them but it’s gonna take a while).
About the ARC - I have tried the same only with a Bryston B60 integrated, the noise has always been there.
The 20ft XLR cables were just an idea so I could move the phono section as far as possible from the speakers (or just to the other side of the room, possibly further from the neighbors wifi router). Otherwise I’m using 3ft Nordost Red dawn XLR between the ARC and the power amp.
@theaudioamp
It’s not only adding the RCA cable to the input but also moving the output cable around (without anything plugged into the EAR preamp)
If I have measured the right place, it’s a zero. I’m not sure what you mean by the signal ground of the phono input. If it’s the pin where the TT ground should be attached then it’s zero.
From the ground pin to the rest of the chassis the meter shows 33 ohms.
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@filipm
"Is there a way to short the inputs without the input shorting plugs? (I have ordered them but it’s gonna take a while)."
Just take a cheap RCA cable, cut off one end and twist the signal cable and the ground/shield wires together. Make two of them, one for left and one for right, then plug the other still good RCA jack ends into the INs left and right. Viola, shorting plugs.
Paul at PS audio has a pretty good talk about it here if you want to get more detail on shorting plugs; Shorting plugs
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Does the noise come out of both channels? If so is it equal out of both? You might also try moving the tubes around.
All the best.
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@filipm
Have you tried turning off your cellphone - not flight mode - turned off completely ?
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@ejb14 ok, signal and ground are twisted together. But the result is the same as if I plugged a regular RCA cable - a lot louder than emtpy inputs.
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Ah - that is very telling. Of what, I am not certain, but it may suggest that your input RCAs are not connected (broken solder joint) to ground in their shields, or there is some other failure internally. If the shorting plugs are correct, it should be silent if the only problem here is RF interference. Is the sound coming from both channels? Try connecting only one output at a time (left or right) to see if one side is better than the other.
To make sure you have the shorting plugs correct, check the connection by using your digital multi-meter and touching the DMM probes to the signal pin and the shield on the plugs - make sure you have a positive connection (most DMMs have a connection test feature that emits a sound or beep when there is a connection.).
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I guess there's nothing that could go wrong making the shorting plugs. I simply cut a piece of cheap RCA cable and connected the signal wire to the shielding wire. It still acts as a regular cable though, basically an antenna.
I measured it with a multimeter - connecting the signal pin and the shield makes a beep.
If there's something wrong in the EAR itself, how's that possible it's working everywhere else except my home? 😫
There's only one thing that made a difference so far - covering everything - the unit and the cables, mainly the cables - into a metal pot. Or making a thick aluminum sleeve for the input cables.
Is it possible that there's an interference between the power cord and the output cables? But again. I tried the same cables at different places. Also, the EAR preamp has been powered with a battery.
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I would make sure the EAR is grounded via the power cord.
@filipm
That it makes more noise with the inputs shorted is telling.
Of course you are living in a high RFI zone; that is why everything works fine elsewhere. Could you clarify this comment:
About the ARC - I have tried the same only with a Bryston B60 integrated, the noise has always been there.
Was the ARC in the system with the Bryston and is that with or without the EAR?
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@atmasphere
I bought the EAR before the ARC LS16 and it's been tested with other things, Bryston B60 was one of them.
I mentioned it because it's a solid state integrated. When I plugged the EAR into the Bryston the noise was still being picked up.
There's an interesting point about the ARC though. When I changed the tubes (it's mk1), uses 4 pieces of 6922, the noise was picked up by the ARC too. It was just very quiet and only when the cage was opened. That set of tubes was used, I think it was either JJ or the stock electro harmonix. I'll try if I can make the ARC to pick up the noise again. Anyways, I think it was only apparent for about a minute and then it disappeared.
I'll have a different set of tubes for the EAR on Sunday.
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@filipm OK. That's 99 44/100% the EAR is at fault. What happens when it is not running off of the battery?
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@filipm
Hmm - perhaps I am missing something but the statement:
"It still acts as a regular cable though, basically an antenna. " - I am not sure is correct once you connect signal to ground. I believe all the energy on the input should be draining to ground at that point.
I just ran this same test (turns out I also created shorting plugs this way once way back when) with an admittedly quiet solid state phono preamp, and with an wifi router right next to the cut wire ends. When the signal wire was not connected to ground wire, I was picking up all kinds of noise from the router through the phono stage - move the wire further away from the router, the noise got quieter.
When I twisted the wires together - absolute silence - nothing, with the wires resting on the router, not even the usual phono stage ocean noise at max volume on the amp.
I wonder if your ground connection on your input RCAs (internally) are not connected (in which case, the shorting plugs would definitely act like an antenna). I suspect the EAR connects all grounds to a single point from the PCB to the case. Is that connection still good?
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@atmasphere when it's not running off the battery - when it's powered from the PS, it's the same except a 50Hz ground loop that is hard to get rid off when powered from the battery.
@ejb14 I can take detailed pictures of the input RCA and post it in here tomorrow.
That makes the most sense so far - no matter what I plug into the inputs, it seems they are never grounded. Therefore the shielding isn't working, right? Maybe that's why the noise gets quieter when I touch the cables, even the output cables - I'm grounding it.
I have tried connecting the chassis of the EAR to many things, I wasn't really succesful so far.
Thanks, I think we're getting closer.
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@filipm (Perhaps) an easy test; take your DMM and with the Ear turned off, verify connectivity between the input RCA jack shields and the ground lug (not the case necessarily) or the output RCA jack shields. On my phono stages they are all connected together.
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@filipm
There's an interesting point about the ARC though. When I changed the tubes (it's mk1), uses 4 pieces of 6922, the noise was picked up by the ARC too. It was just very quiet and only when the cage was opened.
Are you changing tubes while the unit is powered on?
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@ejb14 It's connected, both channels are. The grounding pin of the power input is connected, the case as well (but's it's painted so it can only be measured through the screws or one tiny spot where the paint has been scratched off)
How's that possible the shorting plugs aren't working? (This pictures shows the signal wire and the groung wire of that RCA plug before I twisted them together)
Is it possible that the tubes pick up the signal before it gets grounded?
@audphile1 of course not. Not even plugged in. But I powered it on when I changed the tubes and left the cage opened - to see if they all light up.
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I think your shorting plugs are doing their job, and you have verified that your input shields are properly connected to ground and that the problem lies elsewhere.
Have you verified your power outlets (in the wall) have good ground? You can get a tester cheap at a hardware store. That is another difference between your place and where the EAR worked just fine.
FYI, I just found this link and this guy details a lot of the steps you have done so far, including the shorting plugs. Worth a read -
Trouble shooting phono amplifier and SUT noise
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@filipm 8 days later and you are exactly where you started. You have a broken or poorly designed component or the combination of the two.
You should reach out to the person you bought it from and start working thru some sort of resolution. If it’s too late for that, may be send it in to have a qualified repair tech have a look at it and determine next steps.
Doesn’t look like you’re on the right track here…
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@filipm I am not convinced you have a broken or poorly designed phono stage.
Recap of the evidence so far:
1. You have a predominant 50hz hum in the noise as was analyzed previously.
2. Both the EAR and the ARC LS16 exhibit this noise in your apartment
3. Both the EAR and the ARC have three prong power inlets
4. The EAR routs its ground through the third pin of the power inlet as confirmed by your connectivity test. Presumably the ARC does as well. My Herron tube based preamp, and my Bottlehead tube headphone amp do this as well.
5. The EAR does not exhibit the noise when used in another location (when plugged into a power outlet not in your apartment)
6. The shorting plugs did not reduce the noise
7. Grabbing/touching the cables affected the noise
8. The troubleshooting guide I linked, Bottlehead's trouble shooting guide, and @hagtech 's guide all suggest a 50/60 hz hum/noise is a lifted ground
This evidence suggests you have a lifted ground, possibly either in your power strip, or in your apartment outlets. Assuming the LS16 is not broken or poorly designed, and exhibits the noise too suggests that the EAR may not be broken. That would not make your EAR broken or poorly designed, just not being used as specified (with a good connection to ground).
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Assuming the OP lives in the US, I think it's a bit too simple to blame his issue purely on bad grounding, if you listen to the recorded noise up above. First of all, there is an intermittent burst of 50Hz noise. In the US, we use 60Hz AC, and it's pretty well regulated at that frequency. Typical noise due to grounding issues is at 60Hz or 120Hz. Moreover, it's not intermittent; it's constant. This noise seems due to RFI or EMI from some outside source, though it's true that the susceptibility to the Interference could be related to a poor ground circuit somewhere. There are already a myriad of reasonable ideas for the source and what to do about it in this thread. I hope something works. I am now wondering about bad diodes inside the EAR or the ARC. I am also wondering what did happen or will happen when all the tubes are replaced, though that will not rule out a cold solder joint inside one or the other device.
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@lewm - an excellent point - I was assuming the OP was on 50Hz AC power, based on one of his previous statements in this thread, and the circular plugs in the powerstrip in one of the pics he posted.
@filipm - are you on 50Hz AC or 60Hz AC power? (should have asked this question earlier.)
I plotted the noise spectrum in Audacity, and the 50hz buzz/hum is constant throughout the entire recording at around -17db though it does have very short spikes to -13db intermittently (I think this is the intermittent bursts lewm is talking about). And then there is another spike of a range of frequencies every four seconds.
From the Bottlehead trouble shooting guide:
"Buzzy hum, like a bee - This usually means a lifted ground connection. "
if a lifted ground, then where it is lifted is the question, but a cold solder joint is certainly possible, though I would have thought if so it would have shown itself when the EAR was used at an alternate location.
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@lewm @ejb14 I should have mentioned I live in Prague, Czech Republic. The voltage is 230V and the frequency is 50Hz. I posted it on a local forum but got quickly annoyed by the same jokes some people have been posting for the last two decades over and over.
I was in Berlin yesterday and took my EAR along. It worked perfectly fine even with the cheapest power cord and the interconnects I was using here. I didn't get the tubes yet but I returned with an ARC REF150 power amp. What a beauty.
Ejb, I'm now gonna read the article you have sent. Thanks.
Exactly, if there was a lifted ground on the EAR, it would have been apparent at least at one of the locations I have been to. I wanna try to bring a small intergrated amp and plug it in on the hallway to eliminate the circuit in the apartment.
Is there any test I can do inside the apartment? I invited an electrician and he said the power line should be fine.
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@filipm You could get an outlet tester from Amazon or a hardware store - one that would show open ground/earth would be important. Search Amazon for "outlet tester Prague" (or UK) - You can also use your DMM to test (google how to do it, lots of hits) - just be careful - and use just your right hand to place the probes - do not use both hands - if the outlet is not connected to ground, you don't want to become the ground. If you can, I would get an outlet tester. They are cheap and a great thing to have in this hobby. You likely want to test your power cords too for ground correctness.
I've been in and tested many homes and apartments. Not all were wired correctly, even the newer ones. Check all outlets.
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Is there any test I can do inside the apartment? I invited an electrician and he said the power line should be fine.
Beautiful city Prague.
If you are in an older building, you should get an electrician to verify the male earth pins in the building are in fact grounded. They may not be, or the grounding may be compromised with poor connectivity - corrosion etc.
Also if both the EAR and ARC are grounded through the power cables, then when you connect the 2 units with an RCA cable then you have an earth loop - have you tried lifting the ground on the EAR ( making sure iit is grounded via the ARC by putting a multimeter across the 2 chassis.?
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OP,
Congratulations on the ARC REF150. Great sounding amp.
Now, I would recommend you give up on your EAR and get a ARC PH8… or better yet a ARC REF Phonostage. Each additional piece of ARC is incredibly synergistic… culminating in a really amazing sound with all ARC. Although it makes sense in retrospect, I was really surprised when I dropped in the final ARC piece in my system.
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@dover I already got an electrician over and it was the first thing he did. I demonstrated the problem with the phono preamp, he even brought a 12V battery and we had plugged the EAR into that. I have shared a picture in a one of the previous posts.
Maybe I'll have to call him again, or I'll find someone else to be sure. I will consider getting the tester to do it myself.
The building isn't that old, it's in the center but it's a functionalist building from the 50's. The power line could be 20-25 years old. I'll open up one of the sockets to take a look. The voltage is pretty stable too. The owner takes very good care of it.
I'll definitely call the electrician and make sure he checked it properly. But I think we even checked the grounding outside of the apartment.
There's a different circuit in the kitchen, I tried to power up the EAR from there, no change nor difference in the noise level. I could run a power cable from a socket outside of the apartment.
I have finally bought proper power cables, they are on it's way.
As soon as I sell the Classé power amp I'll get better interconnects too.
I have mentioned this issue in the conversation with the ARC staff as we were discussing the advantages of the ref150 over a ref110 (the use of KT150 tubes) and they basically said I should get the best interconnects I can afford and keep them short.
And yes, I have tried lifting the ground in the EAR's power cord.
@ghdprentice the original idea was to find an ARC PH5, still affordable but all the ARC products are rare in Europe. So is BAT gear or Conrad Johnson. I have read how EAR compares to PH5 and I simply went this way.
I'm a bit afraid I'd have the same issue with any ARC phono too.
The REF150 is great, it gives a lot of room for improvements in the rest of the system. If I get an opportunity to get a good deal on an ARC phono I'll go for it.
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@filipm if you are going to open up a wall socket to check things out, might as well check for DC voltage on your AC power too - just put your DMM to DC volts and the probes on hot and neutral - I don't think it would cause this issue as it typically causes mechanical transformer hum and vibration and not noise in the signal path. However, I suppose the tubes could be picking up that vibration if present via microphonics - and it is another thing that might not be present in another location.
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If tips from phono stage manufs including Jud @ Joule-Electra(RIP), Kevin@K&K and everyone here couldn't resolve it, it was time to move on.
@sbank If that was a JE phono section, the input gain stage was so starved for current that it easily rectifies RF energy and so will be prone to RFI problems. I think Jud didn't want to increase the current to a more linear region as gain was going to be sacrificed.
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@ejb14 There is a transformer hum in the EAR. I thought that's normal. There's also some hum in the LS16. Nothing too loud but when you get head close to the device in absolute silence it's audible.
The electrician didn't make it yet. But I got the shorting plugs. It's the same as the shorting plugs I have made. It makes no difference at all. - that's kind of a hint.
Anyways, today's hifishark found an ARC PH5 stage in Netherlands. I'm thinking of picking it up. It will be interesting to see if it acts the same. I was also always curious how these two compare. If the problem remains, I'll sell one of them and keep looking for the solution or I'll just sell both and get a solid state phono stage.
I think you might be right about the lifted ground. I remember bringing home my first dedicated phono stage. There was some kind of hum too. I don't really know what I did but it disappeared after a while a remained pretty quiet. I also had a Primare R15 phono stage, it wasn't quiet either, there was this white noise at higher volume but neither of them picked the noise like the EAR.
That was the first thing I thought of, the transformer is making noise and the tubes are picking it up. But I would never guess the noise of the transformer is caused by a lifted ground. I'll take the EAR somewhere else again and see if the transformer sounds the same. (I didn't mention it before because it's very quiet and seems normal)
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