Guitar Hum Fault or Feature Why?

[Manfred]

The weapon against humming noise:
https://www.ilitchelectronics.com/produ ... for-strat/

DIY:
https://www.aggh.net/discussion/index.php?topic=49124.0

[RuptorGB]

Your pickups are getting hum/noise from your house wiring/lights/other. That is completely normal for single coils. Worse if you have house wiring problems/dimmers. You didn't answer the question does your Epi with humbuckers do it?

Yes at lower level of 2 to 3 mV, see picture 2mV/div, that is not bothering me like the Strat at almost 10mV. I just realised I probably made my Les Paul kit worse with my resistor summer network because it is about 4mV but still that is acceptable. I shall go back to that later. I wonder if I have been lucky with my capacitor modification that knocks the hum to less than 1mV. It could be all the other impedances and stray capacitances have made a perfect 50 Hz notch filter or created a sharp multi pole roll off because I can't believe the result. If I had a second Strat I would test the capacitor modification on that to see if it gives the same result but I am not rich.
Looking at the suggested Litch hum canceller it has to be tuned effectively telling us every guitar has sufficiently different characteristics that one fixed Litch won't work.
If I put my capacitor modified Strat on a Zoom 3000 setting with lots of gain where you can't move for the hiss the hum can just about be heard but with any other guitar with 2mV or more of hum the hiss disappears relative to the massive hum. So far I have not found a down side to having the capacitor so it stays and I am hum free on a guitar with single coils.

[Tassieviking]

I presume you have lined all the cavities with copper tape and made sure it is connected to the ground lug on the jack socket.
The pick guard and any other covers should also be covered in copper tape.

[plush]

So, uh, when are we going to see the wiring?

[Manfred]

Copper and aluminum are diamagnetic materials that have no shielding effect for low-frequency fields, e.g. at 50/60 Hz.
They are only suitable for shielding higher-frequency signals, such as radio signals or high-frequency radiation from devices such as switched-mode power supplies or electric motor drives.
Ferromagnetic materials such as mu-metal or similar materials with a high nickel content are required to shield low-frequency magnetic fields.

[Manfred]

Here is an article about it, unfortunately it is only available in German.

https://www.youtube.com/watch?v=EIdTC9YfCwo

[plush]

Copper and aluminum are diamagnetic materials that have no shielding effect for low-frequency fields, e.g. at 50/60 Hz.
They are only suitable for shielding higher-frequency signals, such as radio signals or high-frequency radiation from devices such as switched-mode power supplies or electric motor drives.
Ferromagnetic materials such as mu-metal or similar materials with a high nickel content are required to shield low-frequency magnetic fields.

I think you are mixing two both similar but different things here.

Both copper and aluminium (and other highly conductive materials used in Faraday cage) perform great when dealing with _electric_ fields at all frequencies.

As for magnetic fields, then yes, ferromagnetics such as mu-metal and/or annealed steel are the only option.

I can not imagine the household device that generates such strong magnetic field that could be picked up by guitar 1 meter away.

[Manfred]

Sorry, perhaps I wasn't precise enough and kept it short
I will explain what I meant in more detail in the near future.

[RuptorGB]

I can not imagine the household device that generates such strong magnetic field that could be picked up by guitar 1 meter away.

Exactly, magnetic fields are not the source and I put aluminium covers connected to the shield or 0V but they made no difference hence this thread. To answer your other query the capacitor modification eliminated the hum proving the pickups and any wires before the volume pot are the hum receptors. Now which wire is most likely to pick up the electric field hum is it the 3" lengths from the pickups and between tone controls or is it the yards of wire in the loops of the pickups? It is well known the single pickups are far worse than Humbuckers so I can't understand why they are in plastic rather than metal cases like Humbuckers unless that changes the sound dynamics.

[modman]

"Connect to 0V" -- I'm just a hobbyist, but most people would call that 'ground'.
Are you actually playing that guitar through an amp or do you have it connected to the scope all the time?

Strats have humbuckers too: if you put the switch in position 2 or 4.
Many guitarists do take the covers of - metal mass around the pickup does change the tone: tele neck pickup or tele bridge plate.

You could also choose Fender Vintage Noiseless pickups which cost 224EUR -- almost three times the price of your Strat kit. I have a Squier Tele and a P-Bass built from a kit. Both have pickups more expensive that the guitar. If you can't afford that, you'll have to live with the hum, but don't judge Fender guitar by looking at a chinese knockoff kit - especially the pickups.

Silence is a myth... here's 3:34 minutes of silence, it's one of the noisiest recordings you ever heard.

[RuptorGB]

you'll have to live with the hum

What hum? The cap has solved my guitar hum. I don't judge I had a problem that I fixed to my satisfaction and posted it because I thought it would be useful to others. I can't understand why it seems to bother people and why they judge me. Surely someone has done the same before probably before the Internet so nobody knows about it. Mind you given that medicine was shown electricity can kill pathogens (viruses, bacteria & parasites) over 100 years ago and they still ignore it in favour of chopping bits off & poisoning us nobody will even entertain or try the capacitor. Anyway on to the next step of fitting an on board buffer amp to prevent low external impedances from affecting the RC filter output. Can anybody point me to the best or suitable low power buffer amp circuit as I don't want to reinvent the wheel. I guess a class A JFET based buffer is the early type but are there any modern FET based chips or circuits?

[FiveseveN]

nobody will even entertain or try the capacitor

Might it be because they understand how a first order RC HPF works?

given that medicine was shown electricity can kill pathogens (viruses, bacteria & parasites) over 100 years ago and they still ignore it in favour of chopping bits off & poisoning us

Well now I regret trying to help a nut job.

[RuptorGB]

"nut job"?
Irrelevant nasty words from closed minds the trait of all trolls.
Gone to plug my hum free Strat into my 1970's Orange Matamp with 4x12" cabinet to sit and look at it.

[howmuch]

Well I'll be a monkey's uncle this simple modification has made the hum silent. A 10nF capacitor feeding the pickups to the volume control forms a High pass filter that cuts the hum. The lowest note on a guitar is 80 Hz so I arranged the capacitor value to make the filter roll off below that. Being a simple filter it starts cutting the low string but they are always louder due to their size and effect on the magnetic pickup. One can compensate by tilting the pickup closer to the low strings on the Strat but I can't detect the slight reduction in level of the low notes. The simulator figures are about 2dB cut at 80 Hz and 6 dB cut at 40 Hz, the half power point I think, but in the real world there is no hum.
The LTSpice model was only a rough guide to give me a starting point. C1 is the added cap, R1 is the volume & everything to the left of C1 is a single pickup but on the guitar is 3 pickups & tone controls.
I think it is a better solution than loading the pickups with 100 K volume as it only affects the bottom end slightly not the whole guitar range. I will do some more earhole testing but I don't think the sound is any different and I am no longer irritated by the hum.

StratCap.png

Just wanted to point out that the Fender Jaguar has what's affectionately known as the "strangle switch".
This is basically a switchable series capacitor, forming a high-pass filter, like in your schematic.
They use a 3.3nF cap. with 1M pots.
And the Fender/Squier Bass VI also uses the same value cap. and pots. And that's a BASS.

Squier Bass VI Strangle Cap.

SquierBassVIStrangleCap_Small.jpg (16.65 KiB) Viewed 6339 times