Question for the electronics guys....

[TelePaul]

My single coils buzz when I face a particular direction. If I face in the direction of the black arrows, I'm okay but if I move slightly there's a shit load of background noise.

 

[mshilarious]

Your guitar is an aerial, so you pick up different interference signals depending on the direction you face.

 

[TelePaul]

Your guitar is an aerial, so you pick up different interference signals depending on the direction you face.

Is this normal? Normal for single coils anyways?

 

[mshilarious]

Is this normal? Normal for single coils anyways?

It's certainly not unusual, especially if it's an unshielded coil. It depends on how bad the RF environment is. Shielding the pickup will help a little; humbuckers will do better. Also review the shielding and grounding scheme of the control cavity. Using balanced wiring is the ultimate solution, but that's a bit of work.

 

[famous beagle]

Shielding the body cavity and pickguard will help tremendously.

Here's how to do it:

http://www.guitarnuts.com/wiring/shielding/shield3.php

 

[TelePaul]

Hmm I'm wondering what sort of stuff could cause it - lighting, crt monitors, that kinda thing?

 

[mshilarious]

Shielding the body cavity and pickguard will help tremendously.

Except it's probably already shielded (although it's possible something has gone wrong, it's worth a check). Single-coil unbalanced pickups are essentially a broken system. Compare with dynamic microphones. They are single-coil too, but when was the last time you heard an SM58 as noisy as a guitar? Consider that the signal strength of a guitar is 10 times stronger than a dynamic mic, and you realize just how badly guitars work--they have worse SNR with a signal 20dB louder. That's quite an accomplishment.

 

[mshilarious]

Hmm I'm wondering what sort of stuff could cause it - lighting, crt monitors, that kinda thing?

Fluorescent lights, dimmer switches, electric motors, refrigerator compressors, electric heaters. It's a noisy world out there.

 

[TelePaul]

Except it's probably already shielded (although it's possible something has gone wrong, it's worth a check). Single-coil unbalanced pickups are essentially a broken system. Compare with dynamic microphones. They are single-coil too, but when was the last time you heard an SM58 as noisy as a guitar? Consider that the signal strength of a guitar is 10 times stronger than a dynamic mic, and you realize just how badly guitars work--they have worse SNR with a signal 20dB louder. That's quite an accomplishment.

I'll have another look in the control cavity next time it's off but I don't think it's shielded. When you say Unbalanced pickups...can you get balanced single coils?

 

[mshilarious]

I'll have another look in the control cavity next time it's off but I don't think it's shielded. When you say Unbalanced pickups...can you get balanced single coils?

No, you can float them. The problem is there are very few balanced input amplifiers (really just acoustic amps with mic inputs that I know about), and no balanced input guitar pedals I don't think.

It's too bad, because it works perfectly. I wrote about it here:

http://www.naiant.com/guitarwiring.html

Since I wrote that I've become convinced the best approach is a transformer in the guitar. I use a 200K:1K transformer that works great. You lose 22dB with that, but the guitar is now not only balanced but also low output impedance. You can then use a 1/4 TRS to XLR cable, any ol' cable or length, and not worry about cable capacitance. But again, you would currently be limited to using an acoustic amp, or adding a transformer to a regular amp.

 

[TelePaul]

No, you can float them. The problem is there are very few balanced input amplifiers (really just acoustic amps with mic inputs that I know about), and no balanced input guitar pedals I don't think.

It's too bad, because it works perfectly. I wrote about it here:

http://www.naiant.com/guitarwiring.html

Since I wrote that I've become convinced the best approach is a transformer in the guitar. I use a 200K:1K transformer that works great. You lose 22dB with that, but the guitar is now not only balanced but also low output impedance. You can then use a 1/4 TRS to XLR cable, any ol' cable or length, and not worry about cable capacitance. But again, you would currently be limited to using an acoustic amp, or adding a transformer to a regular amp.

Not that I doubt your wizardry...but if this was as credible a solution as you say, wouldn't it be common place? Maybe it is and I just don't know...we're talking quieter than humbuckers?

 

[mshilarious]

Not that I doubt your wizardry...but if this was as credible a solution as you say, wouldn't it be common place? Maybe it is and I just don't know...we're talking quieter than humbuckers?

Beats me. Electrical engineering for guitars and amps has commonly seemed to be lackluster (note the vintage amps that can have potentially fatal grounding schemes). It doesn't help that most guitarists are hyperconservative when comes to instrument design.

Most of what I wrote would be anathema to the purist. Consider that a balanced input/output guitar pedal could no longer be "true bypass" without a gargantuan switch. Of course, if the guitar is low output impedance, then true bypass should be irrelevant, unless the guitar pedal components are crap and then why use it in the first place?

Anyway, the graphs on the site were done with a humbucker. I don't have a single coil guitar, but I expect that would have been more dramatic. Humbuckers are still imperfect because they aren't exactly identically placed. And there is still noise induced in the signal ground and cable because it is all unbalanced. The best you can do unbalanced is to use a humbucker with a cover, and fastidiously shield everything. But that describes the guitar that did that graph pretty well (although I took the cover off the pickup, it's a little brighter that way).

When it's wired balanced, you actually don't have to shield it at all. Doesn't hurt though.

The pickup I have in this guitar I wound by hand, even though it's a humbucker it's only 5K. It's a really bright pickup for a hummer. I got to think somebody makes a stacked humbucker in a single-coil case that is underwound . . . that could help, too.

 

[Anfontan]

Fluorescent lights, dimmer switches, electric motors, refrigerator compressors, electric heaters. It's a noisy world out there.

Absolutely!! I have worked in the Telemetry equipment field for close to 20 years and the airwaves are more saturated with signals every day-and thats only in the audio spectrum. Very high frequencies are even worse...

 

[ggunn]

Shielding the body cavity and pickguard will help tremendously.

Here's how to do it:

http://www.guitarnuts.com/wiring/shielding/shield3.php

It might or it might not. It depends on how well shielded his guitar already is and how severe the EM interference is. I have some medium tension power lines that run alongside my house that give me the same problem, and shielding doesn't help. I have an old (60's) Strat with just the pickguard shield, and one of my friends has a newer Strat with the cavity shielded. They both hum about the same amount when you play facing east or west and are quiet when you face north or south. It's a PITA.

 

[Light]

Shielding the body cavity and pickguard will help tremendously.

Here's how to do it:

http://www.guitarnuts.com/wiring/shielding/shield3.php

Just one note, this guys thing about putting a capacitor in line with the ground to the bridge is completely unnecessary. There is absolutely no way for a properly grounded amplifier with a proper fuse in it to send any current to the guitar, and even if you are stupid enough to run your amp without the right fuse (yes, I said stupid enough, if you run your amp with anything other than the fuse it is designed to run with you are a fucking moron who probably deserves what you are going to get), you are still extremely unlikely to ever have an issue. And even if you did manage to get current running to your guitar, the cap he is suggesting probably would not help.

Beyond that, if you want to shield your guitar it will likely help, but will not fix the problem completely. I prefer to do it with shielding paint, but then I shield enough guitars that I can go through a can in about a year. You would probably never use up a whole can in your life, so there is no real reason for you to buy it. Use either copper foil tape, or just get some aluminum foil and spray adhesive (which is a messy pain to use, but is the cheapest option). It doesn't matter what you use, they all will work about the same, and none of them will make it perfect.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[TelePaul]

It doesn't matter what you use, they all will work about the same, and none of them will make it perfect.


Light

"Cowards can never be moral."
M.K. Gandhi

But it'll help yeah?

 

[Light]

But it'll help yeah?

Probably.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[TelePaul]

Probably.


Light

"Cowards can never be moral."
M.K. Gandhi

Tah light, you're the man. Also, if you happen to be free, maybe ya could look at this guy, particularly his repairs? i'd like some basic work done - set-up, maybe a pickup replaced, grounding and shielding. I think he looks like he knows what hes up to but you might see something amiss

http://www.theguitarworkshop.net/before_after/index.htm

 

[Track Rat]

Paul, on my Tele that I gigged the most with, I ended up putting Duncan stacked humbuckings in it. If the stage was anywhere near a neon sign, the pickups would light up like a pin ball machine. Most single pole pickups like to hum. Of course you could build yourself a Farady Cage out of chicken wire and just play inside of it.

 

[Light]

Tah light, you're the man. Also, if you happen to be free, maybe ya could look at this guy, particularly his repairs? i'd like some basic work done - set-up, maybe a pickup replaced, grounding and shielding. I think he looks like he knows what hes up to but you might see something amiss

http://www.theguitarworkshop.net/before_after/index.htm

Hard to say, without actually seeing his work in person. I dislike how he was doing those peghead repairs, but it IS a very traditional way of doing it. It's just that it is nearly impossible to get the splines to fit properly. We do it in a different way, but that is not in and of itself mean anything. As I said, a lot of people have been using that method for a long time, and it DOES at least show that he is thinking about the right issues when doing those kinds of repairs, even if we disagree about how to actually perform the repair.


Light

"Cowards can never be moral."
M.K. Gandhi