Cycle Hum

Dennis Detweiler · From: Solon, Iowa, US

Any way to eliminate 60 cycle hum from a power station that is 100yds from my house? Using TT single coil pickups. Is it the pickups or line?
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1976 Birdseye U-12 MSA with Telonics 427 pickup, 1975 Birdseye U-12 MSA with Telonics X-12 pickup, Revelation preamp, Carbon Copy Delay and Hall Of Fame Reverb, Crown XLS 1002, 2- 15" Eminence Wheelhouse speakers, ShoBud Pedal, Effects Pedals. 1949 Epiphone D-8.

Georg Sørtun · From: Mandal, Agder, Norway

Most likely the PU picking up radiation.
Precisely tuned notch-filters at 60Hz and 120Hz will pretty much eliminate the hum, no matter the cause.

Brad Sarno · From: St. Louis, MO USA

Georg Sørtun · From: Mandal, Agder, Norway

Lost notes on a PSG is usually not a problem with properly tuned, sharp, notch filters.

E9 barely touches on a 120Hz notch with 10th string in open - low B is 123.5Hz, and that's the "light-attenuated" notch. Nothing but subharmonics below 110Hz even with whole-note lowered 10th string to A.

Extended E9 goes down to around 80Hz. C6 goes lower - 55Hz as absolute lowest AFAIK. Notes dipping into a 60Hz notch filter may be noticeable for those who play a lot around 1st fret on lowest C6 string.

An Alumitone is not very sensitive to LF radiation - humbucker with low-Z and very high Q-point, so Alumitone is an option for replacing a single coil PU if hum is a problem.

Most other humbuckers are wired so hot (high-Z) that they affect the entire mid-range for PSGs - too low Q-point, so most "single coil sound" lovers will be disappointed.

Brad Sarno · From: St. Louis, MO USA

Good point Georg.

Brad

Dennis Detweiler · From: Solon, Iowa, US

Thanks guys!
Yes, both of my guitars are TT wound 18000 and I love the sound (Not the hum).
I have a Furman PQ-3 and can eliminate alot of the hum at around 100hz with bandwidth rolled back to about 2:00 until I hear it coming back again. But, it effects my overall tone more than I can bear.
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1976 Birdseye U-12 MSA with Telonics 427 pickup, 1975 Birdseye U-12 MSA with Telonics X-12 pickup, Revelation preamp, Carbon Copy Delay and Hall Of Fame Reverb, Crown XLS 1002, 2- 15" Eminence Wheelhouse speakers, ShoBud Pedal, Effects Pedals. 1949 Epiphone D-8.

Georg Sørtun · From: Mandal, Agder, Norway

Check availability of narrow band-stop (notch) filters for 60Hz...
http://en.wikipedia.org/wiki/Band-stop_filter
Unlike the low-freq roll-off filter in your EQ, such a notch filter won't affect the overall tone much if at all.

Even better if you have the chance to test out an Alumitone, as then the hum won't be a problem anymore and if the string-balance (height) is right you most likely will hear even more of your PSG's tonal qualities than your TTs can transfer. Whether you like the clearer sound or not is of course a matter of taste Smile

IMO, 18K is too hot even on a single coil, I prefer 14K or lower for "true instrument tone". I never argue with those who "like it hot" though, but then the PU shape the sound and options are limited if hum is a problem.

Bob Martin · From: Madison Tn

Thanks George, that good info, I've used notch filters before to reduce the 60 cycle hum out of audio signals but I never knew that on a steel guitar that the 60 cycle hum could be notched out of the spectrum and not make that much difference. On a regular 6 string electric guitar the theory doesn't seem to apply unless I've been doing something wrong. Please help me or correct me if the same can be done to an electric 6 string and not effect the tonal qualities. thanks

Big Bob
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***Praise God From Whom All Blessings Flow***

Georg Sørtun · From: Mandal, Agder, Norway

Bob, the theory is good for regular guitars - low E is around 82.5Hz. Getting hold of a good, sharp, notch filter for filtering out 60Hz +/- only a few Hz, may not be easy though.

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Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Dennis, more than likely it is not the power lines 100 yards away--just my opinion. More than likely it is something in your home, or the way you are hooking up. Dennis, when I played at the Roy Clark Theatre the hum was so bad I couldn't hardly stand it. I could take the exact same set up home and it was dead quiet. Sometimes odd little things cause hum. I was once testing guitar pedals and got a hum. When I traced the problem down it was the leg of my steel guitar touching a base board heater. Even though the heater was off and the metal was painted metal it still caused a hum. A guitar cord laying on a transformer can cause hum. Those money saving lights that look like a pig's tail can cause more hum than a 4 foot floresent bulb. Dennis, what you need to do is experiement and hunt for the problem. Take your equiment to a different location and see what happens. I would not blame the power lines 100 yards away. The problem is closer! By the way--I built a notch filter that eliminated the exact 60 cycle hum frequency. Trust me--you won't like it if you build a notch filter. If you lose that frequency your steel guitar will sound like a fence post with strings on it.

Georg Sørtun · From: Mandal, Agder, Norway

Am I correct in that the OP wrote "power station", not "power lines"?
A power station is either a producing or redistributing entity, containing transformers, and transformers radiate fundamental AC freq far wider than plain high-Voltage power lines do. 100 yards isn't far for neither high-Voltage power lines or transformers though, and radiation distance depends mainly on Voltage and load.

Anyway, the hum in or radiating from power lines/transformers is mainly fundamental frequency, that can be notched out with a good notch filter with next to zero adverse effect on PSGs' frequency range.

The noise radiating from fluorescent lights and various switching units used around in most homes OTOH, is mainly wideband noise that can not be filtered out without dropping much of the audible range, so they must be eliminated at source or phased out in the PU.

Listening to the hum coming out of the PSG amp, should be enough to determine what type of noise-source one is dealing with.

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