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How to “isolate” AC line noise (hash) from your workbench
#16

Great info here. BTW, having the ground and neutrals tied together in a subpanel is a violation of the NEC in addition to making the ground circuit essentially the secondary of a transformer. If installing a Subpanel, don't forget to remove the ground screw or strap from the neutral bus and ensure a separate Ground Bus is installed. I am not a licensed electrician but I did successfully pass an Underwriter's inspection when I replaced my 1954 electrical Service with a 200 Amp Meter Pan, Outside Disconnect and Feeder Panel. I did much reading of the 2014 NEC which was available in the reference section of our Public Library. It was an interesting project, and the inspector telling my wife that I did a better job than a lot of electricians was worth the $190.00 inspection fee.

Also, interesting and true about the separate ground. There have been discussions regarding tying Radio Ground systems to the electrical ground, however this is likely before all of the computers and switch mode power supplies found in the average house. It is totally impossible for me to run an AM Radio on any station other than my transmitter inside my house or less than 10 feet outside the office or living room of my house. A lot of my 1954 suburban NY "Ranch" (i.e. shack) was wired in 2 conductor Romex with no ground. Maybe something is to be said for Type AC (replaced Type BX) armored cable.

I am now kicking myself for not removing a few EMI Filters during my Field Service career from BioMed and Lab equipment that was being discarded (also 12AX7 Telefunkens from old EKGs in the 1980s). If parting out or tossing out any TVs, most of them will have the caps and parallel wound chokes in their power supplies. However, EMI / RFI filters can be gotten on the internet for prices that may be worth the time savings (although this hobby is about saving, building and rebuilding).

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards, 

MrFixr55
#17

Don't overlook any bad surge suppressors or flaky power taps if you are using any, they can introduce some nasty stuff.




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