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Summoning Elite Troubleshooters
- Thread starter Crosscheck67
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- 60 cycle hum emg emi ground hum
Many thanks to 96 art for sending me two pickups to test with!
I have a pair of those skull transmission style earbuds on, and I have to say it's pretty impressive when you pluck a note on the E string - it makes my temples shake. 
To me, the difference in the tone of the noise between the pickups rules out that it's being caused by something in the signal chain (if it was a noisy preamp, audio interface, cable, etc I'd expect it to be more similar between the pickups). And the directional nature with respect to the orientation of the pickup relative to the power line is pretty typical of good old fashioned EMI. Did the EMGs exhibit the same directional nature for the noise? I'm assuming yes.
I know you did a big foil balloon shielding test. If I were in your shoes, just out of curiosity, I'd probably try to do a last ditch shielding test involving the biggest/thickest conductor I could find. A sheet metal plate or thick mesh screen. Anything bigger than the pickup, thick, and ground-able. Put it between the pickup and the power lines and see if the noise changes. Heck, put the pickup in a (very much unplugged!) microwave or other appliance with a metal chassis, ground the chassis to your jack and see if the noise stops. I'd also like to hear the 96 art pickup with a shielded cable instead of just the twisted leads (and now I wish I'd thought of that earlier). The results of a test like this might or might not translate well to your bass but at least it may give you a firm answer on the noise issue.
Barring really odd scenarios (which aren't possible with the circuit you have), EMI is defeated by hum cancelling coils and shielding - in the absence of a preamp with good noise rejection, that's pretty much it.
To me, the difference in the tone of the noise between the pickups rules out that it's being caused by something in the signal chain (if it was a noisy preamp, audio interface, cable, etc I'd expect it to be more similar between the pickups). And the directional nature with respect to the orientation of the pickup relative to the power line is pretty typical of good old fashioned EMI. Did the EMGs exhibit the same directional nature for the noise? I'm assuming yes.
I know you did a big foil balloon shielding test. If I were in your shoes, just out of curiosity, I'd probably try to do a last ditch shielding test involving the biggest/thickest conductor I could find. A sheet metal plate or thick mesh screen. Anything bigger than the pickup, thick, and ground-able. Put it between the pickup and the power lines and see if the noise changes. Heck, put the pickup in a (very much unplugged!) microwave or other appliance with a metal chassis, ground the chassis to your jack and see if the noise stops. I'd also like to hear the 96 art pickup with a shielded cable instead of just the twisted leads (and now I wish I'd thought of that earlier). The results of a test like this might or might not translate well to your bass but at least it may give you a firm answer on the noise issue.
Barring really odd scenarios (which aren't possible with the circuit you have), EMI is defeated by hum cancelling coils and shielding - in the absence of a preamp with good noise rejection, that's pretty much it.
Are they quieter than the EMG? If so, I wonder what full shielding would do?
Otherwise I'm at a loss and think you need a realtor.
Have you checked the ground in your house to make sure it's actually we working? And your outlet?
I was reading to through a couple of articles on emi interference on the audiophile side, interesting reading.
Over there came the thought of using mic cable to connect everything.
I was reading to through a couple of articles on emi interference on the audiophile side, interesting reading.
Over there came the thought of using mic cable to connect everything.
@dwizum @bdplaid @fig
I have a 7 quart Lodge Dutch Oven with lid. Thick and heavy. Would that work well for this test?
Question for the others: don't different metals filter out different frequencies?
I checked my outlets with a Klein RT250. Some of my outlets are grounded, some aren't. But given my test with all power off, would it matter? Not being rhetorical...truly asking.
I read that's true and almost asked if cast iron has the properties to kill RF from power lines. I was looking at shielding paint a while back...
On bill Lawrence's site he had a bit to say about shielding.
There are differences in shielding between different materials. Copper is really good! Thickness matters as does frequency of the noise signal. As thickness increases, shielding gets better - a dutch oven is so thick that I'd assume the differences in material are washed out, but this is starting to get above my pay grade.
It's probably pretty quick to test. The trick is that the shielding needs to be grounded - connected to the sleeve of the jack. I'm not sure how you'd get a good bond from a dutch oven to your jack. Something like an appliance chassis or a piece of sheet metal (think: old fashioned steel trash can lid) is easy since you can copper tape a wire to it, or connect the wire to one of the chassis screws. If your shielding isn't grounded, then it's basically just acting like a big collection mirror instead of a shield.
Who's having dutch oven roasted pickups for dinner tonight??!!
It's probably pretty quick to test. The trick is that the shielding needs to be grounded - connected to the sleeve of the jack. I'm not sure how you'd get a good bond from a dutch oven to your jack. Something like an appliance chassis or a piece of sheet metal (think: old fashioned steel trash can lid) is easy since you can copper tape a wire to it, or connect the wire to one of the chassis screws. If your shielding isn't grounded, then it's basically just acting like a big collection mirror instead of a shield.
Who's having dutch oven roasted pickups for dinner tonight??!!
I've been on Keto since Easter, so no more homemade fries for me. I'm pretty sure pickups have zero carbs and plenty of minerals so hey...why not?Who's having dutch oven roasted pickups for dinner tonight??!!
If I were to run that test in the cast iron, wouldn't the sheer weight of the lid crushing the ground to the pot suffice? I'm sure soldering to it would get some nasty looks from the Mrs...
Every bass I've had EMG pickups in or EMG pickups and EMG preamps have been DEAD quiet. I suspect it is your outboard gear.
edit, all of my basses with EMGs have been completely un-sheilded as well. JJ's, PJ's DC's, and 45HZ's.
edit, all of my basses with EMGs have been completely un-sheilded as well. JJ's, PJ's DC's, and 45HZ's.
How about a piece of copper tape?
It would be easy to check with a multimeter to be sure you get continuity between the cast iron and the ground lug.
I'm not quite catching the vision...and it's lighting my brain up with novice questions.
- How big a piece?
- Where would it go? If I'm using the adhesive side, I'm assuming that is not conductive?
- The 6" x 11" sheet I have left is what I used for the last shielded test and I soldered to that, but did not ground to the aluminum foil - which could have been a mistake.
- Am I grounding to both the copper tape and the cast iron pot?
