You are here

50Hz Hum & RFI Buzz - Quick and Easy Screening

For all things relating to guitars, basses, amps, pedals & accessories.

50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Jay Menon » Tue Aug 04, 2020 4:47 pm

I posted this over at the fretboard, but its perhaps even more relevant in a recording forum...

If you own / play a guitar that is not screened, or you want to find out what effect comprehensive screening would have on your own instrument (and decide whether it’s worth the time effort and expense) here is a quick and dirty way to find out...

Parts:

1. 1/4” metal bodied jack coupler
2. Short patch cable
3. Longer Guitar cable
Connect them in series

Now the earth is of course connected to the metal body of the coupler (and indeed the jack connector bodies too).

Strap the coupler to bare skin on your leg - Velcro ties work well.

Chain: Guitar - patch cable - coupler - longer cable - amplifier
(apologies for my ugly legs)

Works like a charm. Now when you take your hands off the strings/metal parts your instrument will not buzz any more. And if you're noodling at home / recording, this works fabulously...

With single coil pickups you’ll still have 50Hz hum - it's a good way to see the difference between 50Hz Hum and Inductive RFI Buzz...

Image
Image
Jay Menon
Frequent Poster
Posts: 845
Joined: Sun Sep 30, 2007 12:00 am
Location: Norfolk

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby ManFromGlass » Tue Aug 04, 2020 5:17 pm

Interesting!
Just curious though, I see a second wire running to the floor. What’s that for?
User avatar
ManFromGlass
Frequent Poster (Level2)
Posts: 3347
Joined: Sun Jul 24, 2011 12:00 am
Location: In the woods in Canada

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Jay Menon » Tue Aug 04, 2020 5:22 pm

My earphones...
Jay Menon
Frequent Poster
Posts: 845
Joined: Sun Sep 30, 2007 12:00 am
Location: Norfolk

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby adrian_k » Tue Aug 04, 2020 6:50 pm

Nice one - thanks for that :)
User avatar
adrian_k
Frequent Poster
Posts: 1036
Joined: Thu Jan 30, 2003 1:00 am
Location: Gloucestershire
getting better all the time..

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Wonks » Tue Aug 04, 2020 7:06 pm

Just screen your guitars (if it’s physically possible to) and have done with it. At worst there’ll be no change in normal circumstances (though in a more hostile electrical environment than you normally play in there may be benefits) and at best you get a much quieter, or even near-silent, guitar.
User avatar
Wonks
Jedi Poster
Posts: 10889
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Jay Menon » Tue Aug 04, 2020 7:17 pm

Difficult with a ES335 Wonky...

Actually, the Stratocaster in the picture is beautifully screened. I then installed an Ilitch hum-cancelling backplate - which is wired in conjunction with an RP/RW middle pickup, such that the coil is out of circuit in positions 2 and 4 (the pickups hum-cancel each other).

The coil is in circuit in positions 1, 3 & 5. And it does an absolutely fabulous job.

Interestingly in those positions since the backplate is outside the ‘faraday cage‘ of the cavity screening, there is a mild tendency to pick up inductive RFI buzz.

My little device eliminates that RFI buzz.

On another note, I have Kinman Impersonator pickups and DiMarzio Areas on two other Stratocasters. Each pickup on its own sounds very nice, and indeed comparable with traditional single coils.

In the in between positions however, traditional single coils have a certain magic that none of these hum-cancelling pickups have.
Jay Menon
Frequent Poster
Posts: 845
Joined: Sun Sep 30, 2007 12:00 am
Location: Norfolk

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Wonks » Tue Aug 04, 2020 7:40 pm

What bit of ‘if physically possible’ don’t you understand?
User avatar
Wonks
Jedi Poster
Posts: 10889
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Jay Menon » Tue Aug 04, 2020 7:55 pm

Wonks wrote:What bit of ‘if physically possible’ don’t you understand?

Thank you for that most gracious comment.
Jay Menon
Frequent Poster
Posts: 845
Joined: Sun Sep 30, 2007 12:00 am
Location: Norfolk

Re: 50Hz Hum & RFI Buzz - Quick and Easy Screening

Postby Dynamic Mike » Wed Aug 05, 2020 12:28 am

Jay Menon wrote:
Wonks wrote:What bit of ‘if physically possible’ don’t you understand?

Thank you for that most gracious comment.

Funny, I was expecting a response along the lines of 'Which bit of quick & easy didn't you understand?' but frankly I think I prefer your retort. I shall no doubt be using it tomorrow & claiming it as my own.

Just tried it out on a borrowed bass guitar & it works! Genius. The trickiest bit was digging out the connector (I hate when you can picture something in your mind, but you just can't picture whereabouts you can picture it). Total outlay £0.
Dynamic Mike
Frequent Poster (Level2)
Posts: 3464
Joined: Sun Dec 31, 2006 1:00 am
Is it too late to cancel cancel culture?