Summoning Elite Troubleshooters

Crosscheck

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stratamania said:
They probably recommended it to prevent a possibility of shorting where the jack is. Though you could shield it and then insulate the shielding to prevent any shorting.
It's a tight fit as-is, so that would mean boring the hole out some more which is already pretty big. A little nervous about that.

TBurst Std said:
Crosscheck, which country do you live in?
The good ol' US of A. More specifically in New England, in a small town a few hours from Boston. This means wicked old infrastructure, seemingly upgraded ONLY to meet the bare minimum of industry requirements. Let's just say I sure as hell don't drink the water. I get it delivered. But this means a lot of of homes have electrical wiring which, while safe and legal, isn't the cleanest power you've ever played with.

Logrinn said:
I would also like to add what’s been said before - ground loop.
If EMG doesn’t recommend grounding/shielding you have with the copper foil in essence created what could be a secondary grounding.
I would check this. Before you rip out the copper you could perhaps just remove the pots from the cavity and have them (and the output jack) dangling in the air and try it like that. If the problem disappears, well that’s good, and if it doesn’t at least you haven’t ripped out the copper foil in vain/error.
Could be worth a try.
I just want to make sure I'm on the same page here as the rest of you. Given the facts that EMG has tested all my gear on their bench and found no noise, and that I have played out in places that produce less noise than at my home, is it still worth testing my existing gear for faults or replacing parts? I'm not nay-saying anyone, I'm just trying to better understand.

As for the ground loop theory, some posters have theorized EMI, as I've already tested (some) ground issues, and one user even said I'm essentially using the correct fix for the wrong problem.

I admit it's a vicious cycle; my bass gets noise that others don't, but my bass plays fine at some locations outside my home, so the assumed problem is greater sensitivity and the assumed goal is to provide some fort of EMI protections, which can mean replacing components...replace what I have? Protect what I have? Is that you John Wayne? Is this me?

rick2 said:
Alright ... it's unlikely, but EMG could be wrong.  I'd start by getting rid of all that shielding.  You don't need that with EMG's and as Logrinn said, it could be the culprit.
We tried that approach already :)

Mayfly said:
Hmmmm - if you really do have secondary grounds wired in there, by accident or design, then yea that could contribute.  Might be easier to pull the ground leads off of the electronics one by one and see what happens than to pull the electronics out of the bass, but either will work...

Usually ground loops get noisy when your power is generated by something other than a battery (that is, plugged into a 50/60Hz wall outlet).  In usual hum cases, two pieces of equipment end up at different ground potentials because of those 50/60 current pulses they are dumping into their chassis grounds.  If you complete the loop, by connecting the same audio cable to both, then 50/60Hz current flows in the grounds of your sensitive parts of the circuit, creating the hum.  In your case though, it could be that if you've got a loop in your bass then the loop itself is acting as an antenna and picking up the EMI hash, then happily  transferring it to the grounds of your sensitive electronics.

Solution: break the loop- if ya got one.

Hmmmmm........
I had to read this a few times. Even though I'm a tech guy, I'm a legit noob in the context of guitar and bass electronics. So this is a new one for my understanding. After some posters helped me (I think) rule out ground, here you're saying that grounding could cause the EMI itself. Get me some aspirin. Is it possible, with all the ground/non-ground testing I've done under the guidance of EMG and luthiers who have opened up my bass, could it still be worth testing by pulling any remaining ground connectors off the pots? My number one concern is that I don't want to fry anything.
 

TBurst Std

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2,591
Get something like this and test your outlets. Rewrire as needed. I still feel this is an EMI issue. Try a different outlet and different lighting and appliance utilizations.  Your previous post pretty much it dictates it’s an environment issue, not an instrument

https://www.lowes.com/pd/Kobalt-Receptacle-Tester/5001424383?cm_mmc=shp-_-c-_-prd-_-elc-_-google-_-lia-_-106-_-electricaltoolsandtesters-_-5001424383-_-0&placeholder=null&ds_rl=1286981&ds_a_cid=112741100&gclid=EAIaIQobChMI2aL2sLX87wIVADizAB1ctwjWEAQYAiABEgJ4vPD_BwE&gclsrc=aw.ds
 

TBurst Std

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PS: I never play anywhere without one of those testers.  You got to know what you’re dealing with before debugging.
 

Crosscheck

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TBurst Std said:
Get something like this and test your outlets. Rewrire as needed. I still feel this is an EMI issue. Try a different outlet and different lighting and appliance utilizations.  Your previous post pretty much it dictates it’s an environment issue, not an instrument

https://www.lowes.com/pd/Kobalt-Receptacle-Tester/5001424383?cm_mmc=shp-_-c-_-prd-_-elc-_-google-_-lia-_-106-_-electricaltoolsandtesters-_-5001424383-_-0&placeholder=null&ds_rl=1286981&ds_a_cid=112741100&gclid=EAIaIQobChMI2aL2sLX87wIVADizAB1ctwjWEAQYAiABEgJ4vPD_BwE&gclsrc=aw.ds
Very cool. That's more informative than the ones I have.
 

Crosscheck

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Things just got interesting boys!

The power lines some posters asked about are just in front of the house on the street. So out of curiosity, I plugged in my Amplug and headphones and walked to the back porch, which is the furthest away part.

Test 1: I faced away from the street overlooking the woods (same orientation as how I sit when normally playing at my laptop) and heard some hum. I turned around facing towards the front of the house and the hum was still there, yet half as loud.

Test 2: While listening, I walked from the back porch, through the kitchen, through the dining room and into the living room which faces the street. The entire walk, the hum got louder and louder. I was straight reliving the Back to the Future scene as Marty was firing up the gear in the beginning.

I think this is very telling. I'm going to try again after the wife signs off from work and kill all the breakers to confirm. As suggested, I'm going to include testing turning on one breaker at a time.
 

bagman67

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Sounds like you need to install a Faraday cage around your practice area.  Should be totally convenient and not at all unsightly.


I kid, of course.
 

mayfly

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8,228
Bagman67 said:
Sounds like you need to install a Faraday cage around your practice area.  Should be totally convenient and not at all unsightly.


I kid, of course.

I am reminded of where I used to work where I once walked in on the EMI test lab where an intern was listening to the radio INSIDE the faraday cage.  I expressed my disbelief (as in "WTF Man?!?") to which the intern replied something to effect of "yea it wouldn't work at the start of my term, but then I got it to work by disconnecting this fat wire here...".  :tard:

I wonder how many product tests were screwed up because of that  :)
 

TBurst Std

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2,591
Mayfly said:
Bagman67 said:
Sounds like you need to install a Faraday cage around your practice area.  Should be totally convenient and not at all unsightly.


I kid, of course.

I am reminded of where I used to work where I once walked in on the EMI test lab where an intern was listening to the radio INSIDE the faraday cage.  I expressed my disbelief (as in "WTF Man?!?") to which the intern replied something to effect of "yea it wouldn't work at the start of my term, but then I got it to work by disconnecting this fat wire here...".  :tard:

I wonder how many product tests were screwed up because of that  :)
That’s is so funny
 

Crosscheck

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Ha  :laughing7:  @Bagman67 & @Mayfly know of anyone giving away a cage? I'd actually install it.

For now I'm going to try some heavy duty tinfoil on the wall between me and the street, then just throw a Beatles tapestry over it or something...

BECAUSE, I just ran the breaker test. I had my son use his headphones with my bass and Amplug while I went to the breaker box.

1) I turned off everything, no change, hum remained.
2) I turned on one at a time, no change, hum remained at consistent volume.

So we now know that the EMI - at my place anyway - is emitting from the power lines. I have some test gear on the way, so when that arrives I'm going to do the extra ohm metering, bypassing and elimination tests people have suggested. I'll be back with results.
 

Crosscheck

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Mayfly said:
From all the evidence I still think you've got a ground loop in your bass.
Speaking of which, I now have a multimeter  :headbang:
It's the Harbor Freight 7 Function Digital. Can you guide me though this testing?
 

Rick

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4,311
And if other guitars do not have the same problem then it's your bass not the electricity.

 

Crosscheck

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Mayfly said:
Yes nice looking bass.  I can't see anything obvious in the wiring either.  I would start a process of elimination:  Disconnect parts and see if the hum changes / goes away.  Start at the pickups and work your way up the signal chain.

Chris Kinman said:
There are 2 types of noise, Hum which is cancelled in the pickup and Buzz which can be minimized only by shielding the wiring cavities.

EMG pickups have internal shielding so grounding the strings is not necessary, the loss of sonic performance is compensated for by the active electronics inside the pickup.  Also EMG's are low impedance as is their active controls and that helps greatly to minimize hum.

It is indeed a perplexing mystery but somewhere there is something lurking that is causing this noise.  If it is indeed hum and not electrical buzz.  I can think of only one cause, ground loops.  In high impedance passive circuitry they are not a problem but can be present in active circuitry.  The usual solution to ground loops is star grounding, it's where all ground wires connect to a central ground point and like the tentacles of an octopus the other ends are not connected to anything (I.E. a ground point).  Include shielding connection too in this scenario just to be on the safe side.  It will be a tedious investigation but it might be worth it.

And just for the hell of it try a different lead.  Good luck.  CK

rick2 said:
if Every thing is done perfectly, including grounding, then there’s a defective part somewhere.  Whichever part, I don’t know.  I’d start by swapping out the the most complex parts and work my way to the simplest.  You could accumulate enough parts to make a new guitar, which isn’t the end of the world

TBurst Std said:
PS: I never play anywhere without one of those testers.  You got to know what you’re dealing with before debugging.

Bagman67 said:
Sounds like you need to install a Faraday cage around your practice area.  Should be totally convenient and not at all unsightly.


I kid, of course.

Replying to all. I've been doing a bunch of testing.

- Tburst, I picked up a nice Klein RT250 for testing my outlets. I have a mix of grounded and ungrounded outlets, but they all passed apart form that. However, we can rule this out due to the breaker test I ran after you had suggested testing outlets. But thanks still! It stays in my bag hence forth.

- Mayfly, I picked up a nice Thsinde TRMS 6000 (it's essentially a redone Fluke) auto-sensing multimeter. I tested all pot cases to their respective GND pins. All have continuity.

Now before I indulge all who suggested the presence of a ground loop and shielding everything including the pickup cavities, I tried this first which jives with your other suggestions: I made a custom cable which goes from the pickup, then soldered to the leads on the jack. I then removed everything, disco'd the batteries, tested each pickup independently direct to the jack (I tried two different jacks as well, both grounded to the shielding and not grounded). I was expecting no sound at all because EMG active pickups have their own electronics inside them, yet somehow, they produced a sound. No BTC, no Blend, no Vol, and no power from the batteries.

The hum remains in all scenarios, including direct to my Vox Amplug and headphones. Given this, do you think it's worth shielding the pickup cavities and retesting?

As the noise is so clearly EMI from the power lines, and all the testing thus far, I'm doubting EMG has the capacity to be protected from the sheer amount of EMI I'm getting at home. I'm leaning toward plastering heavy-duty aluminum foil to the wall between me and the street, and also getting an Electroharmonix Hum Debugger. I'm also considering alternate pickups, but I don't know which brand to go with for a warm jazz tone.

That said, I'm still open to suggestions.
 

Crosscheck

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Never heard a response, so I'm including some tests I did if it interests anyone.

[youtube]https://youtu.be/85WOZju2bJs[/youtube]

[youtube]https://youtu.be/laSZZJlz-Yk[/youtube]
 

Crosscheck

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Another big test. An attempt at a Faraday cage made from a cast iron Dutch oven. Three different pickups.

[youtube]https://youtu.be/iwBtJWrCA38[/youtube]
 
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