Differences in sound of the same pickup wound to the same DCR with different wire AWG

[John_H]

Does anybody happen to know; if I wind a single coil with with 42 AWG, and another with 43 AWG, so that for each pickup I get the same inductance and aim for the same resonant peak, will the 43 AWG pickup pick up less RF interference since there smaller coil has less conductive mass, and therefore like a smaller antenna? Could I get a better signal to noise ratio with the finer wire, or should I expect that they would be the same?

If I were you, I would worry more about your guitar cable than this. You're inventing bad solutions for problems that don't exist. Have you ever built a pickup?

[John Kolbeck]

If I were you, I would worry more about your guitar cable than this. You're inventing bad solutions for problems that don't exist. Have you ever built a pickup?

Don't expect me to answer your questions if you won't answer mine.

[John_H]

Don't expect me to answer your questions if you won't answer mine.

It's ok, I know the answer to my question already. If you wish to learn about pickups, I suggest a pro-active approach where you "build" pickups yourself, arrive at some of your own results, and opinions, then discuss those results. What are you trying to achieve? Do you plan to ask five thousand questions, be spoon fed the information, and then build the one perfect guitar pickup. Threads like this are a parasite when it comes to message boards. They suck away time, energy, and bandwidth while pushing the relevant content by people that actually "build" things down to the bottom of the page. Getting snarky with me won't help either. You have already lost the respect that is awarded to most new members. When you come back with a query that is based upon your own research, rather than a shotgun load of "I wonder if" bullshit. I'll be happy to participate. There's an absolute wealth of info in the archived threads. It's a great place to start.

[John Kolbeck]

And yet, despite all the pickups you must have wound, you're unable to answer the question. That's... not really selling me on your trial and error approach.

[rjb]

And yet, despite all the pickups you must have wound, you're unable to answer the question.

You don't seem to realize that John_H did answer your question in post #46.

In real-life practical terms, the difference in RF pickup due to slightly different coil size is insignificant.

[John Kolbeck]

You don't seem to realize that John_H did answer your question in post #46.

All I see in post #46 is "I don't care, so nor should you."

In real-life practical terms, the difference in RF pickup due to slightly different coil size is insignificant.

OK, thank you.

[David King]

I'd guess that the difference in turns area is less than 5%. We are probably talking 1-2dB in noise differential. I.e. you won't hear it.

[Mike Sulzer]

I think it would be more accurate to say that rf pickup in an electric guitar pickup is almost never an important issue. Why?

First, the pickup at rf is just a lossy capacitor, not a very effective antenna. Who knows what the effective values are, but I doubt that you can relate them to the wire size. Second, as someone sort of mentioned, you would expect the wiring between the guitar and the amp to pickup more rf; it is more like an antenna. Also if the pickup has an electrostatic shield, that will keep out rf as well. Third, the input circuit of the guitar amp usually has a large resistor in series with the grid. That in combination with the input capacitance to the first stage, is very effective at eliminating rf.

Are you sure you really are talking about rf interference? What really matters in guitar pickups is hum, harmonics of 60 (50) Hz, from both electric and magnetic fields. rf pickup would be noticeable only if the rf signal is demodulated by a nonlinearity in the amp circuitry, so you might hear an audio signal or more likely these days a digital data signal. Sure, it can happen in very strong rf fields, but it is not a very common problem. If you leave your cell phone on top of some amplifiers, you can hear some pickup.

All I see in post #46 is "I don't care, so nor should you."




OK, thank you.

[John Kolbeck]

I think it would be more accurate to say that rf pickup in an electric guitar pickup is almost never an important issue. Why?

First, the pickup at rf is just a lossy capacitor, not a very effective antenna. Who knows what the effective values are, but I doubt that you can relate them to the wire size. Second, as someone sort of mentioned, you would expect the wiring between the guitar and the amp to pickup more rf; it is more like an antenna. Also if the pickup has an electrostatic shield, that will keep out rf as well. Third, the input circuit of the guitar amp usually has a large resistor in series with the grid. That in combination with the input capacitance to the first stage, is very effective at eliminating rf.

Are you sure you really are talking about rf interference? What really matters in guitar pickups is hum, harmonics of 60 (50) Hz, from both electric and magnetic fields. rf pickup would be noticeable only if the rf signal is demodulated by a nonlinearity in the amp circuitry, so you might hear an audio signal or more likely these days a digital data signal. Sure, it can happen in very strong rf fields, but it is not a very common problem. If you leave your cell phone on top of some amplifiers, you can hear some pickup.

Sorry, I meant all electromagnetic interference, 60Hz and harmonics included. Whatever typically plagues a single coil pickup. If 43 AWG is better than 42 AWG, than maybe 44 AWG is better still. The idea would be to get a quieter pickup without having to resort to humbucking.

[rjb]

rf pickup would be noticeable only if the rf signal is demodulated by a nonlinearity in the amp circuitry, so you might hear an audio signal or more likely these days a digital data signal. Sure, it can happen in very strong rf fields, but it is not a very common problem.

Still, it does happen occasionally.

I used to organize folk music concerts and dances at a hall that was built in 1929, had funky electrical wiring, and was less than half a mile from a commercial AM radio station. We provided the PA systems (different configurations for different events- usually all mic'd vocals and acoustic instruments). Occasionally, if you put your head right next to the main speakers, you could just barely hear the radio station. Until we held that concert with that duo from Hawaii with those electric slack-key guitars. That night, the station came in loud and clear.

At another location, a lodge built by the WPA at a campsite just below Camp David, our PA picked up a conversation in some Slavic language. It was during a break, and IIRC all the channel inputs were muted.
So I doubt that any amount of instrument shielding would have prevented the unintentional eavesdropping.

My girlfriend's Blackberry used to sporadically emit Morse code-like signals that were picked up by every device in the house- including the toaster.

Q: So, what's your point?
A: No point. Just sharing.

Actual Question:
Am I correct in intuiting that lower frequency rf is more likely to cause problems than higher frequencies
(e.g. AM in the 535-1605 KHz band vs. cell phones at 800MHz and higher)?


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Musical Content

[David King]

Sorry, I meant all electromagnetic interference, 60Hz and harmonics included. Whatever typically plagues a single coil pickup. If 43 AWG is better than 42 AWG, than maybe 44 AWG is better still. The idea would be to get a quieter pickup without having to resort to humbucking.

By this reasoning you should go out and get some 46AWG and try winding something with it. If you can get it onto your bobbins without breaking it you might just have something here. If it's still too noisy you can now fit two coils side by side into a strat cover and take the world by storm.

[John Kolbeck]

At resonance, the impedance is at its maximum. Look at the measurement of the impedance of any pickup, for example:[ATTACH]37718[/ATTACH]

Sorry to dig up this older thread, but since this post, I continue to come across contradictory information, saying that impedance is at a minimum at resonance:

http://hyperphysics.phy-astr.gsu.edu...ic/serres.html

For series resonance the condition of resonance is straightforward and it is characterized by minimum impedance and zero phase.

Q and Bandwidth of a Resonant Circuit : Resonance - Electronics Textbook

A series resonant circuit looks like a resistance at the resonant frequency. (Figure below) Since the definition of resonance is XL=XC, the reactive components cancel, leaving only the resistance to contribute to the impedance. The impedance is also at a minimum at resonance.

Intuitively, I'm thinking the reason you have louder signal at resonance is because the pickup is doing the least to resist the flow of current at that frequency. Am I misunderstanding?

[Mike Sulzer]

Sorry to dig up this older thread, but since this post, I continue to come across contradictory information, saying that impedance is at a minimum at resonance:

http://hyperphysics.phy-astr.gsu.edu...ic/serres.html


Q and Bandwidth of a Resonant Circuit : Resonance - Electronics Textbook


Intuitively, I'm thinking the reason you have louder signal at resonance is because the pickup is doing the least to resist the flow of current at that frequency. Am I misunderstanding?

The pickup is a two terminal device with the coil connected to the two terminals, and a correct model for the distributed capacitance is a capacitance connected across the coil. It is thus a parallel resonant circuit that has its maximum impedance at resonance.

Now take this model and add a voltage source in series with the coil. (That is where the voltage is generated by magnetic induction.) The output is taken at the terminals and thus across the capacitor. If you have a cable running to an amplifier, the capacitance of this cable appears in parallel with the pickup capacitance (and is usually larger). Thus you have a kind of low pass filter with an L in series with the voltage source and a C across the input to the amp. If the losses in the coil are small enough and the input impedance of the amp is high enough, you have a resonant low pass filter which has a maximum in its response somewhat before if rolls off, and also its output impedance is highest at this resonance. You should be able to find this kind of low pass filter described in detail on the web.

[John Kolbeck]

The pickup is a two terminal device with the coil connected to the two terminals, and a correct model for the distributed capacitance is a capacitance connected across the coil. It is thus a parallel resonant circuit that has its maximum impedance at resonance.

Now take this model and add a voltage source in series with the coil. (That is where the voltage is generated by magnetic induction.) The output is taken at the terminals and thus across the capacitor. If you have a cable running to an amplifier, the capacitance of this cable appears in parallel with the pickup capacitance (and is usually larger). Thus you have a kind of low pass filter with an L in series with the voltage source and a C across the input to the amp. If the losses in the coil are small enough and the input impedance of the amp is high enough, you have a resonant low pass filter which has a maximum in its response somewhat before if rolls off, and also its output impedance is highest at this resonance. You should be able to find this kind of low pass filter described in detail on the web.

Thanks, that got me on the right track.

[Steve A.]

This kind of questions belong to the Beginner/Hobbyist section.

This thread can be moved there if the folks here think it appropriate.

Steve Ahola
Super moderator

Motion rejected