Hi Everyone
Has anyone managed to successfully eliminate the the buzz through screening that single coil pick ups inherently give off , namely on a strat. The out of phase settings cancel this out but other settings have it. I have tried lining the cavity with copper foil method and also the conductive paint method with minimal success. Is it achievable, or something we have to live with with single coils. I know there are noiseless pick ups out there, but I like what I have.
regards to all
Mike
Stratocaster Pick Up Screening
Moderator: Moderators
Stratocaster Pick Up Screening
mdsc
Re: Stratocaster Pick Up Screening
You can only reduce the noise, never eliminate it completely. A lot will depend on the amount of noise present in the playing environment. A little noise and it might seem the hum is all gone. A lot of noise and it may feel like nothing has changed.
Now, how much screening did you do?
You are trying to make a complete a Faraday cage as possible so you need to put foil or paint all over the underside on the pickguard (or fit an aluminium plate under the pickguard like some early Fenders had). This needs to make good electrical contact with the pots so they ground the screening.
Sometimes the standard triangle of aluminium foil screening underneath the pots and selector switch has a clear plastic layer on it, so I always take off all the pots and switch and put new foil all over it, rather than just putting tape overlapping its edges, as you may not get electrical continuity.
That screening needs to make good physical contact with the screening in the control and pickup routs so that’s grounded. So the cavity rout screening needs to come over the top of the body.
I’ve seen lots of pictures of very neatly screened cavities where the foil stops just short of the top. Looks great and very neat, but does almost nothing. The screening must be grounded to be effective.
And because large areas of plastic, like pickguards, tend to warp over time, it is best to run the cavity shielding out to a few pickguard screw holes, so the pickguard and body screening are firmly held together. You could run a ground wire between the two, but I feel there are normally enough wires to fit in the control cavity without adding another long wire to fit in without getting them trapped between the body and pickguard.
Now, how much screening did you do?
You are trying to make a complete a Faraday cage as possible so you need to put foil or paint all over the underside on the pickguard (or fit an aluminium plate under the pickguard like some early Fenders had). This needs to make good electrical contact with the pots so they ground the screening.
Sometimes the standard triangle of aluminium foil screening underneath the pots and selector switch has a clear plastic layer on it, so I always take off all the pots and switch and put new foil all over it, rather than just putting tape overlapping its edges, as you may not get electrical continuity.
That screening needs to make good physical contact with the screening in the control and pickup routs so that’s grounded. So the cavity rout screening needs to come over the top of the body.
I’ve seen lots of pictures of very neatly screened cavities where the foil stops just short of the top. Looks great and very neat, but does almost nothing. The screening must be grounded to be effective.
And because large areas of plastic, like pickguards, tend to warp over time, it is best to run the cavity shielding out to a few pickguard screw holes, so the pickguard and body screening are firmly held together. You could run a ground wire between the two, but I feel there are normally enough wires to fit in the control cavity without adding another long wire to fit in without getting them trapped between the body and pickguard.
Reliably fallible.
Re: Stratocaster Pick Up Screening
Hiding to nothing dayna, or to very little.
I did some tests with a well screened Strat clone some years ago and relative to a 'medium strummed lowest E chord' I got a noise level of some -70dB FS when the guitar was optimally oriented. That was good enough for what son was doing at the time but of course pretty noisy in the context of modern digital kit.
The problem seems to have died down in forums now but say 5 years ago many guitarists were 'coming in from the cold' and trying home recording with this new fangled 'digi-gear'. Many of them were appalled at how noisy the guitar/amp combination was! In a pub the punters are always creating a 45dB SPL 'noise floor' (and for some reason drummers can never be quiet for more than 5 seconds!). I was fortunate to spend a little of my time with a top amp designers who was OCD about residual noise and the company produces amps with some of the best S/N specs' on the planet.
I'll try that Strat into my M4 later and post some numbers.
Dave.
I did some tests with a well screened Strat clone some years ago and relative to a 'medium strummed lowest E chord' I got a noise level of some -70dB FS when the guitar was optimally oriented. That was good enough for what son was doing at the time but of course pretty noisy in the context of modern digital kit.
The problem seems to have died down in forums now but say 5 years ago many guitarists were 'coming in from the cold' and trying home recording with this new fangled 'digi-gear'. Many of them were appalled at how noisy the guitar/amp combination was! In a pub the punters are always creating a 45dB SPL 'noise floor' (and for some reason drummers can never be quiet for more than 5 seconds!). I was fortunate to spend a little of my time with a top amp designers who was OCD about residual noise and the company produces amps with some of the best S/N specs' on the planet.
I'll try that Strat into my M4 later and post some numbers.
Dave.
Re: Stratocaster Pick Up Screening
It's certainly worth trying, though the results can be variable. It certainly won't make things worse and it can make things considerably better. I know people who've shielded noisy single-coil guitars and basses and they say it's made them near silent. But it will depend on may things, like how much of the pickup is sticking above the scratchplate (and so how much of the coil is above the shielding) the direction the noise is coming from and the sheer level of electromagnetic noise present.
It's also not going to stop hum picked up from being too close to transformers in amps etc.
At home, my non-shielded single coil guitars don't make much noise anyway unless I get too close to the amp. So when I do shield a guitar, it's hard to say if it's made a big or small improvement. But for a small outlay, I think its worth doing.
Just watch out for unintentional shorting of the signal on the shielding. Always best to stick some insulating tape underneath 3- and 5-way Tele/Strat lever switches as their input/output solder tags always sit very near the bottom of the control cavity.
Reliably fallible.
Re: Stratocaster Pick Up Screening
And it is possible to screen the pickups themselves using this method.
https://www.premierguitar.com/diy/mod-g ... il-pickups
I've never tried it, but the basic principle is good, especially when used in conjunction with cavity screening. It still leaves the top of the pickup open, so not perfect, but short of fitting metal covers or switching to hum cancelling or active low impedance pickups, you won't be able to do much better.
You'd need to be careful when soldering a ground connection to the foil coil screen as it's all too easy to overdo the heat and damage the coil wire insulation or melt away some wax if the coils are dipped and leave the pickup prone to microphonics. I'd personally try and solder a wire to pre-cut but not-yet-applied copper tape and then add it to the pickup. And if you think it adversely affects the sound, then it's also easily reversible.
https://www.premierguitar.com/diy/mod-g ... il-pickups
I've never tried it, but the basic principle is good, especially when used in conjunction with cavity screening. It still leaves the top of the pickup open, so not perfect, but short of fitting metal covers or switching to hum cancelling or active low impedance pickups, you won't be able to do much better.
You'd need to be careful when soldering a ground connection to the foil coil screen as it's all too easy to overdo the heat and damage the coil wire insulation or melt away some wax if the coils are dipped and leave the pickup prone to microphonics. I'd personally try and solder a wire to pre-cut but not-yet-applied copper tape and then add it to the pickup. And if you think it adversely affects the sound, then it's also easily reversible.
Reliably fallible.
Re: Stratocaster Pick Up Screening
Wonks wrote: ↑Wed Dec 07, 2022 11:32 am
It's certainly worth trying, though the results can be variable. It certainly won't make things worse and it can make things considerably better. I know people who've shielded noisy single-coil guitars and basses and they say it's made them near silent. But it will depend on may things, like how much of the pickup is sticking above the scratchplate (and so how much of the coil is above the shielding) the direction the noise is coming from and the sheer level of electromagnetic noise present.
It's also not going to stop hum picked up from being too close to transformers in amps etc.
At home, my non-shielded single coil guitars don't make much noise anyway unless I get too close to the amp. So when I do shield a guitar, it's hard to say if it's made a big or small improvement. But for a small outlay, I think its worth doing.
Just watch out for unintentional shorting of the signal on the shielding. Always best to stick some insulating tape underneath 3- and 5-way Tele/Strat lever switches as their input/output solder tags always sit very near the bottom of the control cavity.
Slight misunderstanding there Wonks? I did not mean to suggest that screening a guitar cavity was pointless. On the contrary, very necessary and I consider guitar makers that don't do so very remiss.
No, my statement "hiding to nothing" was meaning EVEN WHEN you have a perfectly screened guitar it will still pickup some noise and there is a limit to how quiet you can get one in any particular case.
I don't think I/we have mentioned noise gates? Either hard or software. I had a Behringer BCA2000 ten or more years ago. Rubbish drivers and proved to be electrically unreliable but it had a cracking noise gate in it on the High Z input.
"THINKS!" It is still in the loft I wonder if I can carve the gate circuitry out of it?
Dave.
Re: Stratocaster Pick Up Screening
There aren't any reversed polarity ('out of phase') positions on a standard Strat. The pickups are simply wired in parallel and it's the closer proximity of the pickups to each other (compared to say the bridge and neck pickups on a Tele or a Les Paul) that means the sound detected by each pickup is quite similar. As the pickups are sensing from different points along the string the peaks and dips of the various harmonics don't correspond that well, so there are more phase reinforcements and cancellations than on most other guitars with two pickups selected.
Your middle pickup will be RWRP wound (reverse wound reverse polarity). The combination of reversed magnetic poles and the pickup coil connected in reverse means the string output is still the same polarity as the neck and bridge pickups, but any noise signal is reverse polarity (so hence the hum cancelling).
In the very early years, Fender Strats had the same pickup in all three positions, so no hum cancelling in positions 2+4 , but the with the 3-way switch, they didn't have those positions (apart for the jamming half-way option), one reason they didn't bother with RWRP middle pickups until around 1985 (though I think Seymour Duncan and others had them as options before then on their replacement pickups).
If you actually wire them out of phase (which I've done by accident when mixing pickups from different manufacturers) the sound is really thin indeed and not that useable.
Reliably fallible.
Re: Stratocaster Pick Up Screening
How would running the single coil pick up cables through metal sheath Braiding and grounding that to the pot casing to earth(Like seen on some older Gibson Humbuckers) How would that Fare
mdsc
Re: Stratocaster Pick Up Screening
It would help a very small amount, but once you shield the cavity, there should be no noise getting in the cavity so would then be of minimal use. The metal braid is simply acting like the copper cavity shielding.
The pickup coil has the greatest length of wire in it, maybe 6000 turns or more at maybe 12cm length per turn. So that could be 720m or more of coil wire compared to maybe 30cm of pickup and output wire length. So a coil is going to pick up far more noise than the pickup lead itself.
So braided or foil screening for the connection wires works well in unscreened cavity situations and is basically mandatory for noise reduction in big hollow-bodied guitars that are impossible to internally foil screen.
It won’t do any harm to add it if you have shielded cavities but it’s adding bulk to the wires and with thick vintage cloth-covered wires, turning and squeezing them all under the bridge pickup when fitting the scratchplate on can be tricky at the best of times without the extra girth the braid would give.
The pickup coil has the greatest length of wire in it, maybe 6000 turns or more at maybe 12cm length per turn. So that could be 720m or more of coil wire compared to maybe 30cm of pickup and output wire length. So a coil is going to pick up far more noise than the pickup lead itself.
So braided or foil screening for the connection wires works well in unscreened cavity situations and is basically mandatory for noise reduction in big hollow-bodied guitars that are impossible to internally foil screen.
It won’t do any harm to add it if you have shielded cavities but it’s adding bulk to the wires and with thick vintage cloth-covered wires, turning and squeezing them all under the bridge pickup when fitting the scratchplate on can be tricky at the best of times without the extra girth the braid would give.
Reliably fallible.
Re: Stratocaster Pick Up Screening
Is there a technique or procedure known to screen the coils themselves.
mdsc
Re: Stratocaster Pick Up Screening
Some pickup types are totally screened in metal (Brass?) of course but I would think enclosing a plastic cased pickup in foil would change its tonal qualities? Eddy currents and all that swaddlin'.
But the bottom line surely is, how noisy IS the guitar. I have done as I promised and checked my Strat copy. A full E chord hit -13dBFS and leaving all controls set and moving the guitar around I get a minimum of -78dBFS and a worse case of about -65dBFS. I would say those noise figures are 'good enough for jazz'?
Guitar was about 750mm from this Lenovo laptop and the AI was a MOTU M4. Git cable was a 5mtr Klotts/Nuke 'silent plug'. At my feet was a chunky 17 0 17 volt 50Hz transformer feeding a Behringer mixer.
Running the 24bit/44.1kHz clip through Right Mark analyser showed no 50 Hz nor 100Hz, There was a maximum peak at 81Hz as you would expect.
TBH I doubt that running the guitar through an amp and using a mic would improve that signal to noise ratio much if at all?
Ooops! Correction, you can't run a 24 bit .wav through RMA, not my version anyway. The original recording was 24 bits but I had to convert it to 16 for the analyser. Makes little difference since 16 bits still has a far lower noise floor.
Dave.