Pickups Q and resonance
- Thread starter walters
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STRATDELUXER97
Stratoblaster Tone Meister
Re: Pickups Q and resonance
Newbies are only allowed to ask 1 question at a time! LOL :laugh2: :laugh2:
Great questions,but hard to answer?
walters said:
Newbies are only allowed to ask 1 question at a time! LOL :laugh2: :laugh2:
Great questions,but hard to answer?
Stevo
Tonus Maximus Pacificas
Re: Pickups Q and resonance
When you have capacitive reactance equal to inductive reactance, you have resonance - In a guitar pickup, overall resonance is also influenced by string vibration and the pickup's magnet also.
The variable Q can be found by dividing the total bandwidth by the resonant frequency.
The bandpass range can also be calculated as frequencies above .707 on the total bandwidth curve. The .707 comes from an integral sin-squared(x)dx from 0 to pi, or, the square root of 1/2. That integral is very common in engineering methods.
When you have capacitive reactance equal to inductive reactance, you have resonance - In a guitar pickup, overall resonance is also influenced by string vibration and the pickup's magnet also.
The variable Q can be found by dividing the total bandwidth by the resonant frequency.
The bandpass range can also be calculated as frequencies above .707 on the total bandwidth curve. The .707 comes from an integral sin-squared(x)dx from 0 to pi, or, the square root of 1/2. That integral is very common in engineering methods.
Last edited:
STRATDELUXER97
Stratoblaster Tone Meister
Re: Pickups Q and resonance
Holy smokes what is inside of your pipe there Steve! :smokin: :smack: :laugh2:
You sound like a rocket scientist....:laugh2: :laugh2: :laugh2:
Stevo said:
Holy smokes what is inside of your pipe there Steve! :smokin: :smack: :laugh2:
You sound like a rocket scientist....:laugh2: :laugh2: :laugh2:
Re: Pickups Q and resonance
to make a further explanation, resonance occurs when a load is excited with an alternating source (sine) and the impedance of that load is solely real, which means that the inductive and capactive impedance of the load is cero, and the resistance part of the load is some number. say z is the impedance of whatever load. under not resonant circumstances, "z= R + ix" where R is the real resistance and X is another resistance, but accompained by the "i" which makes it imaginary. under resonant circumstances, "z= R1" whereas R1 is another resistance, purely real. its worth to mention that in our guitars, the load is considered the guitar pickup (bobin), the resistances of the Pickup in DC, the reisstance of the volume control and the tone capacitor. To find the resonant frequency of the pickup, there you have to find the equivalent value of that whole load in a Z=R+iY form, then take iY and equal it cero, solve for w (you know a capacitve or reactance impedance is 1/jwc or jwL )
The 0.7 value, or root square of 1/2 can be seen as 70%. In a low pass filter (our guitars pickups) the bandwith frq is when the amplitud of the signal drops below 70% (or when it drops 3dB). The frequency where that happens is called the bandwith freq.
to make a further explanation, resonance occurs when a load is excited with an alternating source (sine) and the impedance of that load is solely real, which means that the inductive and capactive impedance of the load is cero, and the resistance part of the load is some number. say z is the impedance of whatever load. under not resonant circumstances, "z= R + ix" where R is the real resistance and X is another resistance, but accompained by the "i" which makes it imaginary. under resonant circumstances, "z= R1" whereas R1 is another resistance, purely real. its worth to mention that in our guitars, the load is considered the guitar pickup (bobin), the resistances of the Pickup in DC, the reisstance of the volume control and the tone capacitor. To find the resonant frequency of the pickup, there you have to find the equivalent value of that whole load in a Z=R+iY form, then take iY and equal it cero, solve for w (you know a capacitve or reactance impedance is 1/jwc or jwL )
The 0.7 value, or root square of 1/2 can be seen as 70%. In a low pass filter (our guitars pickups) the bandwith frq is when the amplitud of the signal drops below 70% (or when it drops 3dB). The frequency where that happens is called the bandwith freq.
octavedoctor
New member
Re: Pickups Q and resonance
My word! And i keep getting told that my posts are too technical!
The above is all correct, but to cut through some of the jargon,
Impedance is like resistance, but some components have a different impedance at some frequencies than at others, which is why it is called impedance and not resistance.
The frequency at which a component's impedance is least will determine it's "natural" or resonant frequency, and signals passing through this component will pass most easily at this frequency.
In general terms, a components Q is the resonant frequency of a circuit, rather than a component , and it does not exist in isolation. In a guitar pickup circuit there will be a coil, a capacitor and a resistor, each of which will have their own resonant peak, the combination of which will conspire to create the global circuit's Q factor.
The reactance of a component, mentioned above, is a measure of the degree to which the component changes the phase relationship of an applied signal (a similar concept to the hysteresis lag in electromagnetic circuits, but i'm trying to keep this simple)
When you have several components whose impedance and reactance are frequency sensitive you have what is called a "time circuit"; Typically this consists of a capacitor, a coil and a variable resistor.
Changing the Q factor of a component in isolation is pretty hard without changing the physical properties which govern reactance and impedance but the global Q of a circuit can be changed by changing the value of one of the above components, usually the resistor, so in fact the closest thing you can get to a multi-tapped Q is the pickups tone control; varying the resistance of the pot adjusts the circuits time constant, which is a function of the components impedances and reactances. This time constant is the Q factor...
In fact, since a tapped single coil or a split humbucker also changes the impedance of the coil in the time circuit this is technically doing the job as well.
DonLduk said:
My word! And i keep getting told that my posts are too technical!
The above is all correct, but to cut through some of the jargon,
Impedance is like resistance, but some components have a different impedance at some frequencies than at others, which is why it is called impedance and not resistance.
The frequency at which a component's impedance is least will determine it's "natural" or resonant frequency, and signals passing through this component will pass most easily at this frequency.
In general terms, a components Q is the resonant frequency of a circuit, rather than a component , and it does not exist in isolation. In a guitar pickup circuit there will be a coil, a capacitor and a resistor, each of which will have their own resonant peak, the combination of which will conspire to create the global circuit's Q factor.
The reactance of a component, mentioned above, is a measure of the degree to which the component changes the phase relationship of an applied signal (a similar concept to the hysteresis lag in electromagnetic circuits, but i'm trying to keep this simple)
When you have several components whose impedance and reactance are frequency sensitive you have what is called a "time circuit"; Typically this consists of a capacitor, a coil and a variable resistor.
Changing the Q factor of a component in isolation is pretty hard without changing the physical properties which govern reactance and impedance but the global Q of a circuit can be changed by changing the value of one of the above components, usually the resistor, so in fact the closest thing you can get to a multi-tapped Q is the pickups tone control; varying the resistance of the pot adjusts the circuits time constant, which is a function of the components impedances and reactances. This time constant is the Q factor...
In fact, since a tapped single coil or a split humbucker also changes the impedance of the coil in the time circuit this is technically doing the job as well.
Re: Pickups Q and resonance
Thanks guys for the help and information
Whats the difference between tapped coil impedance VS a split coil impedance?
What sets the resonant frequency of a pickup? is it the number of wire turns and the magnet?
What sets the Capacitance in a pickup?
"capacitive reactance equal to inductive reactance, you have resonance"
How do i get the capacitive reactance equal to the inductive reactance?
The wire= resistance
coil= magnet with pole pieces
capacitance= ?
Thanks guys for the help and information
Whats the difference between tapped coil impedance VS a split coil impedance?
What sets the resonant frequency of a pickup? is it the number of wire turns and the magnet?
What sets the Capacitance in a pickup?
"capacitive reactance equal to inductive reactance, you have resonance"
How do i get the capacitive reactance equal to the inductive reactance?
The wire= resistance
coil= magnet with pole pieces
capacitance= ?
Re: Pickups Q and resonance
-Whats the difference between tapped coil impedance VS a split coil impedance?
A\ A coil tap is a bobin split anywhere it's wound, au contraire as a split coil, which in the guitar world is a humbucker split in a single (a bobin split in half). If the coil tap is done right in the middle, then the coil tap is the same a split humbucker(coil)
-What sets the resonant frequency of a pickup? is it the number of wire turns and the magnet?
A\ Well, a pickup by itself can be seen as load with impedance which can get into resonance because it has inductane, it has a resistance (the resistance provided by the lenght of the cable) and a capacitance (parasites caps, produced by the different layers of wire wound around and around). If you notice, both the resistance and the capacitance in a pickup are very small because they are side effects of the bobin, and appear there un-intentional, so trying to measue these values is very hard because they are very small and start to affect measures only at very high frequencies (around gigahertz, as it does in a transistor). Thats why you try to find the resonant frequency of a system you can control, a system composed by the pickup as the bobin, the tone capacitor, and the tone pot and volume pot. the pickup adds the inductance part only (ignoring the side effects, like the resistance and the capacitance it creates) and adding yourself your own resistor and capacitor.
So to answer your question, If you have fixed resistor and capacitor for tone controls, and then the only variable that changes the resonant frequency is the pickup's inductance, it can be changed, since the inductance depends of number of turns, wire gauge, wire length, and the core of the bobin (alnico, ceramic, etc..)
-What sets the Capacitance in a pickup?
A\how close the wires are to each other. if you wound the cable around a cylinder, and the wound it again over itself, creating 2 layers, those 2 layers can be modeled as 2 paralel plates, with a transversal area and a distance between them. Thats a capacitor.
Wire gauge and lengh, and type can also be used.
-How do i get the capacitive reactance equal to the inductive reactance?
A\read and understand whole post again....
The most common way to do resonant is by adding elements. Say you know the inductance of the bobin and you know the resistors of the tone pot and you want your load to resonate at a certain frequency (say you want it to resonate at 1khz) You only have one variable left, the capacitance, so you find the total impedance of the load (adding resistors and impedances of bobin and capacitor in the form of jwL and 1/jwC.) and then equaling the imaginary part of it to cero, and in this case, solving for C. You know L, you know R, and you know w. solve for C.
just out of curiosity, what are all these questions for? are you familiar with this stuff?
-Whats the difference between tapped coil impedance VS a split coil impedance?
A\ A coil tap is a bobin split anywhere it's wound, au contraire as a split coil, which in the guitar world is a humbucker split in a single (a bobin split in half). If the coil tap is done right in the middle, then the coil tap is the same a split humbucker(coil)
-What sets the resonant frequency of a pickup? is it the number of wire turns and the magnet?
A\ Well, a pickup by itself can be seen as load with impedance which can get into resonance because it has inductane, it has a resistance (the resistance provided by the lenght of the cable) and a capacitance (parasites caps, produced by the different layers of wire wound around and around). If you notice, both the resistance and the capacitance in a pickup are very small because they are side effects of the bobin, and appear there un-intentional, so trying to measue these values is very hard because they are very small and start to affect measures only at very high frequencies (around gigahertz, as it does in a transistor). Thats why you try to find the resonant frequency of a system you can control, a system composed by the pickup as the bobin, the tone capacitor, and the tone pot and volume pot. the pickup adds the inductance part only (ignoring the side effects, like the resistance and the capacitance it creates) and adding yourself your own resistor and capacitor.
So to answer your question, If you have fixed resistor and capacitor for tone controls, and then the only variable that changes the resonant frequency is the pickup's inductance, it can be changed, since the inductance depends of number of turns, wire gauge, wire length, and the core of the bobin (alnico, ceramic, etc..)
-What sets the Capacitance in a pickup?
A\how close the wires are to each other. if you wound the cable around a cylinder, and the wound it again over itself, creating 2 layers, those 2 layers can be modeled as 2 paralel plates, with a transversal area and a distance between them. Thats a capacitor.
Wire gauge and lengh, and type can also be used.
-How do i get the capacitive reactance equal to the inductive reactance?
A\read and understand whole post again....
The most common way to do resonant is by adding elements. Say you know the inductance of the bobin and you know the resistors of the tone pot and you want your load to resonate at a certain frequency (say you want it to resonate at 1khz) You only have one variable left, the capacitance, so you find the total impedance of the load (adding resistors and impedances of bobin and capacitor in the form of jwL and 1/jwC.) and then equaling the imaginary part of it to cero, and in this case, solving for C. You know L, you know R, and you know w. solve for C.
just out of curiosity, what are all these questions for? are you familiar with this stuff?
Re: Pickups Q and resonance
Thanks for the information and help
I'm trying to understand pickup theory more and the basics behind it so i can learn about pickups more
I'm trying to build a pickup that will have multiple switches to have different twangs timbre/tones/notches/midranges do u know how i can start?
How can i get diffferent notches out of a pickup?
THe fender jaguar and early 61-63 strats were surf twang notches
what were these notches and midranges because a pickup has a frequency response curves and the surf twang pickups had a midrange/notches frequency response curve do u know what it looked like?
How can i take a regular normal "Flat response pickup" and add or modify it to have twang?
I'm trying to make a Surf Multi-Twang pickup with a selector switch to have different Surf Twangs
Thanks for the information and help
I'm trying to understand pickup theory more and the basics behind it so i can learn about pickups more
I'm trying to build a pickup that will have multiple switches to have different twangs timbre/tones/notches/midranges do u know how i can start?
How can i get diffferent notches out of a pickup?
THe fender jaguar and early 61-63 strats were surf twang notches
what were these notches and midranges because a pickup has a frequency response curves and the surf twang pickups had a midrange/notches frequency response curve do u know what it looked like?
How can i take a regular normal "Flat response pickup" and add or modify it to have twang?
I'm trying to make a Surf Multi-Twang pickup with a selector switch to have different Surf Twangs
Re: Pickups Q and resonance
I have a strat but the pickups have no twang just "Flat" frequency response how do i change them to have midrange twangs
The fenders 50's and 60's all had different midrange twangs
I'm thinking about having a new Surf pickup with different Midrange curves,shapes,midrange taps,midrange frequencys to get like 20 or more twangs out of #1 pickup how do i do this ?
I'm not a designer but i just had the idea but i need some feedback so i can explain better what im trying to say
How can i make this surf pickup i mean what do i need to do ?
I have a strat but the pickups have no twang just "Flat" frequency response how do i change them to have midrange twangs
The fenders 50's and 60's all had different midrange twangs
I'm thinking about having a new Surf pickup with different Midrange curves,shapes,midrange taps,midrange frequencys to get like 20 or more twangs out of #1 pickup how do i do this ?
I'm not a designer but i just had the idea but i need some feedback so i can explain better what im trying to say
How can i make this surf pickup i mean what do i need to do ?
Re: Pickups Q and resonance
I'm not going in other people threads causing problems i keep to my own so whats the problem that i talk about guitar pickups and information i want to know if u don't like me why do u come in my threads and report me for no reasons thats not nice i don't go in your threads and do this.
I'm not going in other people threads causing problems i keep to my own so whats the problem that i talk about guitar pickups and information i want to know if u don't like me why do u come in my threads and report me for no reasons thats not nice i don't go in your threads and do this.
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