What's all the hummin about??

[scartozi]

I do realize that there is conductive tape and paint but all that aside what is causing all the humming?

Guitar #1 MIA Strat
Fender factory Noiseless pickups, TBX mid boost and all original pots.
no conductive tape/paint, only the plate between the pots and pickguard
Plugged in: No noise at all

Guitar #2 MIM Strat
Fender custom shop pickups, it think aftermarket pots (previous owner)
No conductive tape/paint with foil between the pots and pickguard
Plugged in: Noisy as hell

Guitar #3 MIM Strat
Fender factory MIM pickups and pots
No conductive tape/paint with foil between the pots and pickguard
Plugged in: Noisy as hell

So, is it the noiseless pickups making guitar #1 so quiet?....I mean I know they are noiseless pickups.
How much would painting the cavity with conductive paint really help?

Should I change out the 5 way switch, pots and capacitor to better quality?

I'm just now diving into the electronic part of Strats so any help would be great.

 

[bagman67]

Short form answer: Yes, the noiseless pickups are what's eliminating the noise on the guitar with the markedly diminished hum.


Conductive paint, shielding tape, etc., may have some effect (you'll get conflicting stories here and abroad on the wide and woolly interwebz), but it's unlikely to make a truly substantial difference when it comes to good ol' 60-cycle AC hum.  If you don't want hum, don' t use single coil pickups - use humbuckers (which, in some flavor or another, is what your Fender factory noiseless pickups are).

 

[AutoBat]

Depends on the source of your noise.  If it's 60 cycle, that's just what they do. Does it go away or mostly so when you select position 2 & 4?
If you said 'no' then checking the wiring for cold solder points may help.
My guess is that it's probably a case of TADTS ( http://www.urbandictionary.com/define.php?term=TADTS )

 

[Cagey]

What Bagman said. It's the pickups. Single coils behave much like mile-long antennae, and there's no shielding them. Grounded conductive paint or foil in the pickup/control cavities will not have any noticeable effect and is a waste of time/expense/effort. Your wiring should be shielded, but with single coil pickups pretty much anything you do amounts to barking at the moon.

 

[line6man]

Noiseless pickups are humbuckers, IIRC. That means that 60Hz hum is reduced by common mode rejection.

Note that shielding works on electric field noise, and 60Hz hum is magnetic field noise.
Under the condition that it actually works and you can hear the difference (That's quite questionable, as you have an incomplete Faraday Cage, but that's for Cagey to rant about.), you should hear a reduction of electric field noise only.

 

[Cagey]

That's correct - noiseless pickups are "humbuckers". "Humbucking" is just a trade term, and it refers to pickups that utilize common mode noise rejection, as you say. Low impedance pickups such as EMG makes are also noiseless, as are piezos.

CMNR works at any frequency, it just so happens that what we hear the most from guitars/basses is the most dominant frequency, which is usually a harmonic of 60hz.

 

[scartozi]

I appreciate all the info. Like I said....I'm just getting into the whole pickup, pots thang. I have been use to playing my strategy with the noiseless pickups and that's probably why I notice such a difference. One of my MIM strats the noise is redder depending on where the 5 way switch is located. I'd have to plug it in to find out. I think I'm going to get the upgrade kit for both of the MIM strats and rewire them so I know they are done right. The one with the custom shop pickups looks like a mess so I don't know if the person knew what they were doing or not. I believe they are Texas specials but I'll have to check for red and blue dots and yellow wire.....should I change the capacitor or install the one with the upgrade kit?

 

[Cagey]

Capacitors in extremely low-power circuits like guitars usually last about 74,291,442 years or longer, so unless you don't like the response curve or somebody installed something ridiculous there's no real reason to change it.

 

[scartozi]

So what you're saying is they don't last very long then.....better buy 2 :icon_biggrin:

What's with the oil paper caps and isn't there one called black ice or something? Or are these just sales gimmicks to get people to spend money with no noticeable change.....placebo effect

 

[Cagey]

What's with the oil paper caps and isn't there one called black ice or something? Or are these just sales gimmicks to get people to spend money with no noticeable change.....placebo effect

There are reasons to use capacitors with different construction, but it generally has to do with two things. One is mechanical strength. Some caps need to be able to take a lot of physical abuse due to their environment. Vibration, wide temperature swings, etc. In that same category is packaging and connection scheme, which is usually dictated by device construction. Some need to be small, some need coaxial leads, some are surface mount, etc.

The other consideration is withstand (or working) voltage. Some circuits operate with much higher voltages present than others.

There are many other considerations, but those are the two biggies.

There's a myth in the guitar world that different capacitors "sound" different. It's horse pucky. For one thing, capacitors don't have a sound, but that's just swinging at low-hanging fruit. The reality is that .022μf is .022μf no matter how the capacitor is constructed or packaged. It can be an oil/paper, mylar, metal film, ceramic, tantalum, electrolytic, polyester, whatever cap, and if it's supposed to have .022μf of capacity, that's what it'll have within a range of tolerance.

When you look at the formula for capacitive reactance, there's no variable for working voltage. It's all about capacitance and frequency. Since the reactance is what you're interested in when you're making audio filters (tone controls), those are the only things you need to pay attention to. You do all the math to get the performance you want, then you pick parts that have the values you need and will withstand the physical/electrical environment.

In a guitar, the voltages are very small and the environment is closely moderated. So, there's no need to use paper/oil, mylar, or many of the fancy caps available. Those materials are all used for dielectrics (insulators) and are chosen for their varying ability to withstand or insulate against voltage. Paper over oil is usually a high voltage part, often in excess of 600vdc. You'd have to be hit by lightning for your guitar to ever see voltages like that, and in that case, I doubt you'd be worried about your guitar's tone control failing <grin>

So, since essentially all you need concern yourself with in a guitar's "tone" circuit is capacitance and resistance, you can use the smallest package at the lightest voltage you can find that has the capacitance that you need, and it'll work exactly the same as the biggest package at the highest voltage you can find.

There's a lot of controversy about this on all the music forums, but it's mostly just misunderstanding about what's actually going on. There are even some well-intentioned videos where guys try to show with elaborate mockups how the differences play out. Don't pay any attention to it. I've seen them all, and they're all flawed studies so the results are inconclusive, even when it sounds as though what they're "proving" is true. They never control for all the variables, so they draw false conclusions.

Just buy the cheapest ceramic caps you can find at the capacity you want, and you'll be fine. The little ones Warmoth sells for $.50 cents are perfect. If you buy them in bulk from Allied, Mouser, RSE et al, they're only 2 or 3 cents apiece and they'll work the same as the $25 epoxy-sealed oil over paper parts that are the size of a half roll of dimes and barely fit in your control cavity.

 

[scartozi]

Thanks cagey for the explanation! I'll just use the one from the rebuild kit.

 

[line6man]

So what you're saying is they don't last very long then.....better buy 2 :icon_biggrin:

What's with the oil paper caps and isn't there one called black ice or something? Or are these just sales gimmicks to get people to spend money with no noticeable change.....placebo effect

IIRC, the Black Ice is two Schottky diodes in inverse parallel, that sound like absolute shit in a guitar. If you want to get into that, buy some twenty cent diodes, don't pay the $30 or whatever they are charging.

 

[Cagey]

So what you're saying is they don't last very long then.....better buy 2 :icon_biggrin:

What's with the oil paper caps and isn't there one called black ice or something? Or are these just sales gimmicks to get people to spend money with no noticeable change.....placebo effect

IIRC, the Black Ice is two Schottky diodes in inverse parallel, that sound like absolute shite in a guitar. If you want to get into that, buy some twenty cent diodes, don't pay the $30 or whatever they are charging.

That's it. StewMac sells them for $27.50 + shipping.

They do sound like shit, though. The original Vox? Univox? Fuzz pedal used that trick 100 years ago to chop off the peaks of the waveforms, then amplify what was left before sending it along for your amplifier's preamp to freak out on. Basically amplifying square waves. Keef used it on "Satisfaction", and you can hear it on Norman Greenbaum's "Spirit in the Sky". Since then it's become somewhat common, especially in low-end gear. Although, Marshall was doing it for a while in the JCM 900 series amps. Common mod was to just clip the little bastards out, and you'd end up with a hotter preamp as a result and the thing would just scream like you'd expect. Much better sound, and it was a no-cost mod.

 

[Super Turbo Deluxe Custom]

If you want to dive in and get your hands dirty and familiarize yourself with guitar wiring, we all encourage that.  However, IMO, a rewire kit isn't necessary.  By turning the tone pot, you know if it's working or not.  A rewire kit won't make single coils not hum.  Like mentioned, the in between positions on a Strat (2 and 4) are humbucking, so they shouldn't hum.

 

[bagman67]

If you want to dive in and get your hands dirty and familiarize yourself with guitar wiring, we all encourage that.  However, IMO, a rewire kit isn't necessary.  By turning the tone pot, you know if it's working or not.  A rewire kit won't make single coils not hum.  Like mentioned, the in between positions on a Strat (2 and 4) are humbucking  as long as your middle pickup is reverse wound/reverse polarity, so they shouldn't hum.

FTFY.


Bagman

 

[Alfang]

Cagey put out a lot of good info, but I will disagree with one thing, as i always do with cagey, god bless his intent.

you don't need shielded wire for 3 inches of wire, that mile long antenna won't care about 3 inches of wire.

However, In cageys defence, theres no harm in using shielded cable

 

[scartozi]

I plan on keeping these guitars and although I can't say for certain I'm sure the MIM strats don't have great quality pots, switch and cap. If I'm wrong please let me know....all I'm looking for are good electronic parts. I don't mind spending $50-60 on two wiring kits for my MIM strats if the quality of the replacement parts are better than what is in them. Am I expecting it to solve all my problems...no, just want good equipment.

 

[Cagey]

you don't need shielded wire for 3 inches of wire, that mile long antenna won't care about 3 inches of wire.

Replace the shielded wire going from your volume pot to the output jack with unshielded wire, then let me know how that works out.

Edit: Once you've done that and quickly unplugged your guitar from the amp, then before you put the shielded wire back, paint the inside of the control cavity with conductive paint, or line it with foil, and ground it. Then, try plugging it in again and let me know how that works out.

Finally, put the shielded wire back.

 

[Cagey]

I plan on keeping these guitars and although I can't say for certain I'm sure the MIM strats don't have great quality pots, switch and cap. If I'm wrong please let me know....all I'm looking for are good electronic parts. I don't mind spending $50-60 on two wiring kits for my MIM strats if the quality of the replacement parts are better than what is in them. Am I expecting it to solve all my problems...no, just want good equipment.

I'm sure you've heard the old saying: "If it ain't broke, don't fix it!"

 

[scartozi]

I plan on keeping these guitars and although I can't say for certain I'm sure the MIM strats don't have great quality pots, switch and cap. If I'm wrong please let me know....all I'm looking for are good electronic parts. I don't mind spending $50-60 on two wiring kits for my MIM strats if the quality of the replacement parts are better than what is in them. Am I expecting it to solve all my problems...no, just want good equipment.

I'm sure you've heard the old saying: "If it ain't broke, don't fix it!"

Well what's the fun in that :icon_biggrin: ......."if it ain't broke, make it better"