Noisy Humbuckers

Colnago

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Your guitar is fine.
This guys explains it the best.
 

ChubbyFingers

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^ Seen it.

That's why I figured it was because we had just cleaned the carpets.

Nonetheless I'm figuring if I can't isolate the transmitter, I can at least do everything I can to shield the receiver.
 

donepearce

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^ Seen it.

That's why I figured it was because we had just cleaned the carpets.

Nonetheless I'm figuring if I can't isolate the transmitter, I can at least do everything I can to shield the receiver.
I'm pretty sure the effect has nothing to do with the hygiene state of your carpets. 50/60Hz hum fields exist in any house that has mains wiring. If you find you can change the level of hum by turning your body, the effect is purely magnetic and works directly into the pickups. Your body is not involved. This is the kind of interference that is louder in single coils and is cancelled by humbuckers.
 

ChubbyFingers

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I think you missed the part where it was observed that by touching the strings, thus grounding oneself through the guitar and amp, the hum goes away.

Moreover, humbuckers, if a reminder is needed, are used quite deliberately to cancel out hum that the pickups, um, pick up.

Shielding everything else hasn't worked, so the only things left to shield are the wires between the switch and the control cavity.
 

Go Nigel Go

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If your amp has a polarity switch, try giving it a flip. I have several amps that have one, and it has cured hum on more than one occasion. Playing in dive bars, I have seen a whole host of electrical deficiencies at the stage. Electrical outlets are supposed to be standardized with the same prong always being the "hot" and the other being the "neutral". If the outlet isn't wired correctly the "hot leg" will be on the wrong side of the plug and can cause hum in many amps. Flipping the polarity switch basically "changes the prongs" inside your amp, which is handy when you are playing someplace where the wiring is suspect. Saved my butt a few times for sure.
 

donepearce

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If your amp has a polarity switch, try giving it a flip. I have several amps that have one, and it has cured hum on more than one occasion. Playing in dive bars, I have seen a whole host of electrical deficiencies at the stage. Electrical outlets are supposed to be standardized with the same prong always being the "hot" and the other being the "neutral". If the outlet isn't wired correctly the "hot leg" will be on the wrong side of the plug and can cause hum in many amps. Flipping the polarity switch basically "changes the prongs" inside your amp, which is handy when you are playing someplace where the wiring is suspect. Saved my butt a few times for sure.

Polarity switches have probably killed more musicians than the legendary curse of the 27th birthday. Fortunately neither legal nor possible in the UK.
 

ChubbyFingers

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Polarity switches have probably killed more musicians than the legendary curse of the 27th birthday. Fortunately neither legal nor possible in the UK.
I don't know if polarity switches are illegal in the UK, but theyre certainly unnecessary, given the design of the beloved 13 amp plug..

On the subject of which,, ast time I was in the UK, nearly v a decade ago now, it was virtually impossible to find a DIY 13-amp plug. I needed a bunch for computer power cords and the like and couldn't find them anywhere nearby.

Moulded on to a ready made power cord, yes, standalone plug, no.

Maybe it was an EU regulation, or maybe Brits no longer know how to, or more likely can no longer be bothered to, wire up a plug, I don't know.

Mind you, it's pretty much the same in the US too.

Just for the record, I'm an ex pat Brit.

"Four candles..."
 

donepearce

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The ability to wire a plug was pretty much a rite of passage into manhood when I was young. Electrical equipment was sold without plugs, so the ability to attach one was mandatory. I guess the fire services eventually lobbied the government to make the process illegal. Once moulded-on connectors were a thing, that legislation became easy. Now we only have to deal with the other end of the mains lead - the loathsome IEC connector which loses its ground without telling you.
 

ChubbyFingers

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The BS1363 13 amp plug is a thing of engineering beauty.

Did you know it was introduced in 1947, seventy-five years ago?

The 13 amp rating was chosen to deliver the current needed for a 3-bar electric fire, 3 kW. 240 volts (the at the time regulation voltage) x 12.5 amps = 3 kVA, so 13 amps was just over that.

The wiring was intended to be foolproof (but remember what Douglas Adams wrote about "the ingenuity of complete fools"), a fuse built into each plug, a cable anchor, a ground prong that connects before the others, and, if meeting the British Standard, a socket with shutters raised by the ground prong being inserted. The original bakelite material was the best plastic for the job at the time, and the thickness ensured it couldn't short or shock people touching it. And you basically have to take a hammer to the things to break them.
 

donepearce

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The BS1363 13 amp plug is a thing of engineering beauty.

Did you know it was introduced in 1947, seventy-five years ago?

The 13 amp rating was chosen to deliver the current needed for a 3-bar electric fire, 3 kW. 240 volts (the at the time regulation voltage) x 12.5 amps = 3 kVA, so 13 amps was just over that.

The wiring was intended to be foolproof (but remember what Douglas Adams wrote about "the ingenuity of complete fools"), a fuse built into each plug, a cable anchor, a ground prong that connects before the others, and, if meeting the British Standard, a socket with shutters raised by the ground prong being inserted. The original bakelite material was the best plastic for the job at the time, and the thickness ensured it couldn't short or shock people touching it. And you basically have to take a hammer to the things to break them.
It is indeed the best mains plug in the world. It has one disadvantage. If you unplug it and drop the lead on the floor, your bare foot will find all three of those pins in the middle of the night.
 

ChubbyFingers

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It is indeed the best mains plug in the world. It has one disadvantage. If you unplug it and drop the lead on the floor, your bare foot will find all three of those pins in the middle of the night.
Right next to the Lego brick or the cat turd on the stairs:wow:
 

ChubbyFingers

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Going completely off on a tangent...

Are you old enough to remember when builders put electric fires on the wall over bathtubs?

I remember my parents buying a brand new house around 1970, which had one.

My dad, then a young, now a retired, industrial HVAC and building services engineer, took one look at the thing and promptly ripped it off the wall before the teachests were even half unpacked.
 

ChubbyFingers

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Two cord bundles made up, ready to go in. One for the Epi LP, one for my P90 thinline.

I've dispensed with the switch ground wires, just adding "talis" soldered to the sheathing. Heat shrink was put over the ends to smooth things out for pulling through and to stop the braided fraying. 20220505_081257.jpg
 

donepearce

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Going completely off on a tangent...

Are you old enough to remember when builders put electric fires on the wall over bathtubs?

I remember my parents buying a brand new house around 1970, which had one.

My dad, then a young, now a retired, industrial HVAC and building services engineer, took one look at the thing and promptly ripped it off the wall before the teachests were even half unpacked.

I certainly do. My first real experience with an electric fire war a free-standing three-bar. It was bonfire night and I wanted to light a sparkler. So I did the obvious thing and poked it into the glowing coils. Didn't do that again.
 

donepearce

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Two cord bundles made up, ready to go in. One for the Epi LP, one for my P90 thinline.

I've dispensed with the switch ground wires, just adding "talis" soldered to the sheathing. Heat shrink was put over the ends to smooth things out for pulling through and to stop the braided fraying. View attachment 48032
That will do very nicely
 

ChubbyFingers

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I certainly do. My first real experience with an electric fire war a free-standing three-bar. It was bonfire night and I wanted to light a sparkler. So I did the obvious thing and poked it into the glowing coils. Didn't do that again.
My paternal grandfather was in the RAF from near the end of WW2 until 1936. He did two long tours overseas, one dropping bombs on Iraq, the other dropping bombs on Afghanistan. Go figure.

At some point I think he must have contracted malaria, because even in summer he'd sit next to a burning Parkray, and in winter one of those ancient chimney like paraffin heaters (talk about a fire hazard!) came out too.
 

Go Nigel Go

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I don't know about the British electrical system (other than that it is different). In the US, guitar amps are all 110 volts, and some of the places I was playing the polarity switch on my amp was probably the safest thing on the stage... :D
 

ChubbyFingers

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Domestic supply used to be 240 volts RMS 50 Hz, single phase.

The Europeans used to run at 220 volts RMS, also 50 Hz. In some parts of Europe, if you want more than 20 kW, you have to have a 3 phase supply, broken out in the breaker box.

At some point in the late 80s or early 90s, the UK was having trouble keeping supply up to 240 volts, mainly in the southeast, due to demand. The French, on the other hand, had built so many nuclear power plants, they were having trouble keeping the voltage down to 220.

So in a rare act of common sense from the EUSSR, the pan European (well, EU and the rest of western Europe), standardized on 230 volts RMS, 50 Hz.
 

ChubbyFingers

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Back on subject...

I fitted my shielded switch wiring to the LP this afternoon, and I'm pleased to say it has significantly reduced the hum. Not entirely eliminated it, but down to a level that I can't differentiate it over my Marshall Origin50's regular "yeah they all do that" background noise.
 


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