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Topic: single coil hum question |
Jim Rossen
From:
Iowa, USA
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Posted 16 Dec 2016 6:38 pm |
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My double neck has one single coil per neck. It has a neck selector switch that is near-both-far. There is a soft hum at near and far and no hum and reduced output in the both position. Is the hum situation expected?
Thanks
Jim |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 16 Dec 2016 7:04 pm
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That's pretty normal behavior when the pickups are wound with opposite magnetic polarities and opposite winding connections. Together in that configuration, they "buck" hum. That's how humbuckers work in general. It's also how modern Stratocasters are made, so the "bridge + middle" or the "neck + middle" settings are humbucking.
Unfortunately, that tone you get with "both" pickups on may not be ideal, and that leaves you still with the single coil hum problem when in noisy environments.
But when the noise at a gig is real bad, that "both" humbucking position can save you.
Brad |
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Jack Hanson
From:
San Luis Valley, USA
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Posted 16 Dec 2016 8:06 pm
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| Brad Sarno wrote: |
| But when the noise at a gig is real bad, that "both" humbucking position can save you. |
Or, you can carry one of these (just in case):
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Jim Rossen
From:
Iowa, USA
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Posted 16 Dec 2016 9:22 pm
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Thanks Brad and Jack
The guitar has metal necks and cab sides. Will using shielded cable help?
Jim |
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Mike Perlowin
From:
Los Angeles CA
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 16 Dec 2016 11:29 pm
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The only way to set up a perfect "humbucking single coil PU" with single-coil sound, is to use two identical (or properly calibrated) single coils, each loaded by its own active buffer, with signal mixed together in anti-phase after the buffers. One single coil PU is mounted as normal, and the other where it picks up the same noise-fields but not the strings.
Difficulty lies in placing the second PU on/in the instrument, and balance the two PUs out in the post-buffer mixer, but when successful the result is single coil sound with no tonal loss, and next to zero hum even in the worst electrical environments. |
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Tony Prior
From:
Charlotte NC
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Posted 17 Dec 2016 4:28 am
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The only REAL way to eliminate the HUM of a single coil is to replace it with a Humbucker. 
_________________
Emmons L-II , Fender Telecasters, B-Benders , Eastman Mandolin ,
Pro Tools 12 on WIN 7 !
jobless- but not homeless- now retired 9 years
CURRENT MUSIC TRACKS AT > https://tprior2241.wixsite.com/website |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 17 Dec 2016 6:17 am
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| Jim Rossen wrote: |
Thanks Brad and Jack
The guitar has metal necks and cab sides. Will using shielded cable help?
Jim |
Very little. Most of the hum is entering via the pickups. |
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Bob Hoffnar
From:
Austin, Tx
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Posted 17 Dec 2016 7:30 am
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| Brad Sarno wrote: |
That's pretty normal behavior when the pickups are wound with opposite magnetic polarities and opposite winding connections. Together in that configuration, they "buck" hum.
But when the noise at a gig is real bad, that "both" humbucking position can save you.
Brad |
I'm not so sure that the polarities have much to do with it. I think it is more about phase cancellation with is greatly diminished by the distance between the 2 necks. Mainly the hum is reduced because overall output is cut in half when both necks are engaged.
I known it's common knowledge that polarity is how humbucking pickups work but in my experiments it didn't do anything. I talked with other pickup builders and they said they just let people think it does because it's easier than trying to explain it.
_________________
Bob |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 17 Dec 2016 8:06 am
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| Bob Hoffnar wrote: |
| Mainly the hum is reduced because overall output is cut in half when both necks are engaged. |
Mainly so, yes. Two PUs in parallel load each other, quite non-linearly too.
| Bob Hoffnar wrote: |
| I known it's common knowledge that polarity is how humbucking pickups work but in my experiments it didn't do anything. I talked with other pickup builders and they said they just let people think it does because it's easier than trying to explain it. |
The LCR circuit for interacting coils are inherently difficult to explain, and most humbuckers are designed through trial and error, and then replicated. |
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Jim Rossen
From:
Iowa, USA
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Posted 17 Dec 2016 9:55 am
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Seems like some the conditions cited in Georg's message are present in my guitar as there is no hum in the both position. What is involved in implementing the "active buffer" and mixing to achieve the full output single coil sound?
Thanks
Jim |
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Jim Kennedy
From:
Brentwood California, USA
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Posted 17 Dec 2016 10:04 am
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I have no idea if this would work on a psteel, but you can shield the cotrol cavity on single coil guitars and star ground them. Even this does not totally eliminate hum, but it made a drastic difference on the Strat I did ths to. In bars with lots of neon and flourescent lights, it keeps the noise down to a quite tolerable level. Just google star grounding and shielding for guitars.
_________________
ShoBud Pro 1, 75 Tele, 85 Yamaha SA 2000, Fender Cybertwin, |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 17 Dec 2016 11:18 am
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| Jim Rossen wrote: |
| What is involved in implementing the "active buffer" and mixing to achieve the full output single coil sound? |
In essense it is two identical buffer circuits (think two FreeLoader or similar) - one for each PU, followed by a potentiometer to balance and sum the output of the two buffers. Single coil PUs will then sound like single coils, because they are loaded as single coil PUs should be. Hum and electric noise will be canceled out when the two PUs are connected in 180 deg phase to each other and levels balanced (fine-tuned) via the pot following the two buffers.
Years ago I saw a circuit presented on this forum that split a humbucker PU's two coils into two buffers for a somewhat similar "single coil sound out of a humbucker" effect, but I cannot find that circuit now. Such a circuit will work the same way if two single coil PUs are run through it. |
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Tony Prior
From:
Charlotte NC
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Posted 18 Dec 2016 8:47 am
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years back I had Wallace True Tones on my Carter, they were excellent, until I played the room from HxLL. I won't go into the room details as it just doesn't matter.
After a really nice call with Jerry, , I explained what was going on, what the room was like, the stage, the lighting, the dimmers, all that stuff. He gave me a really good overview but at the end of the conversation he said, you should probably just cave and put the Humbuckers back on !
he was right ! 
_________________
Emmons L-II , Fender Telecasters, B-Benders , Eastman Mandolin ,
Pro Tools 12 on WIN 7 !
jobless- but not homeless- now retired 9 years
CURRENT MUSIC TRACKS AT > https://tprior2241.wixsite.com/website |
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Jerry Jones
From:
Franklin, Tenn.
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Posted 18 Dec 2016 3:55 pm
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Here's a hum cancelling differential amp I posted a while back.
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Jerry Jones |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 18 Dec 2016 4:21 pm
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| Jerry Jones wrote: |
| Here's a hum cancelling differential amp I posted a while back. |
In its simplest form that's pretty much it. |
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