I know a guy that completely changes the sounds of guitars by changing the passive electronics and I want to learn the math that will enable me to do this too. In particular, I want to understand the impedance curves when interacting with tone caps and how these are effected by the different wiring layouts. If there isn't a reference on the net that takes all this into account, maybe this can become a sticky.
Hi,
Download SPICE-Based Analog Simulation Program - TINA-TI - TI Software Folder
And learn how to model passive pickups and their
wiring. Don't forget connecting cable capacitance.
FWIW building good models is not easy at first.
rgds, sreten.
Model pickups as an AC voltage source with series R and L.
Download SPICE-Based Analog Simulation Program - TINA-TI - TI Software Folder
And learn how to model passive pickups and their
wiring. Don't forget connecting cable capacitance.
FWIW building good models is not easy at first.
rgds, sreten.
Model pickups as an AC voltage source with series R and L.
Last edited:
sreten
Yeah, I'm on the SPICE learning curve as we speak. It took me a week to figure out that every circuit needs a ground to be valid so partial circuit parameters can't be simulated.
boobtube
I've seen that but all the stewmac links are geared toward generating sales and are not comprehensive in my opinion. I appreciate the help and look forward to more input.
Yeah, I'm on the SPICE learning curve as we speak. It took me a week to figure out that every circuit needs a ground to be valid so partial circuit parameters can't be simulated.
boobtube
I've seen that but all the stewmac links are geared toward generating sales and are not comprehensive in my opinion. I appreciate the help and look forward to more input.
I get really into this too. Here is my excel spreadsheet that I have developed over the last few years:
Its intended to be very interactive as you change value, call up different tone circuits etc. its called GuitarFreak:
GuitarFreak - guitar frequency response calculator | GuitarNutz 2
Underlying it, is a block of complex number arithmetic that works out the signal levels at each point in the circuit. I have tested it against Spice simulations and it gets a very close match.
Its intended to be very interactive as you change value, call up different tone circuits etc. its called GuitarFreak:
GuitarFreak - guitar frequency response calculator | GuitarNutz 2
Underlying it, is a block of complex number arithmetic that works out the signal levels at each point in the circuit. I have tested it against Spice simulations and it gets a very close match.
Wow! This is a really cool spreadsheet and page you linked JohnDH. The only thing it doesn't tell you how to do is measure the inductance and capacitance of your pickup and wiring. Thanks much, these should keep me busy for a while but in the interim, here are some questions:
If I want a gradual roll off of volume from high output should I use a linear taper or reverse/forward log volume pot?
Why do lower output single coils tolerate high loads (low resistance) better than high output humbuckers?
Tone cap values aside, when using a 500K volume pot, which tone pot value will allow me to retain the greatest brightness, 250K, 500K, 1000K?
If I want a gradual roll off of volume from high output should I use a linear taper or reverse/forward log volume pot?
Why do lower output single coils tolerate high loads (low resistance) better than high output humbuckers?
Tone cap values aside, when using a 500K volume pot, which tone pot value will allow me to retain the greatest brightness, 250K, 500K, 1000K?
Hi terrences, thanks for your comments, I hope GuitarFreak will run for you.
You can measure resistance with a multimeter, but inductance is much more important and most meters dont include it. But there is enough info on the net to estimate the value even if your pickups dont have published data, by looking at similar models. The spreadsheet has some typical values built in which may be enough to help make decicions, recognizing that these analyses are only a visual approximation to tone.
For pot tapers i like the effect oc a standard log pot with a treble-bleed resistor and cap, which slows and smoothes the taper. For tone pots, a higher value is brighter, but with less control in the low range. I quite like a no-load pot which goes to infinite at 10. You can test the relative effects of these options witb the spreadsheet.
Good luck
You can measure resistance with a multimeter, but inductance is much more important and most meters dont include it. But there is enough info on the net to estimate the value even if your pickups dont have published data, by looking at similar models. The spreadsheet has some typical values built in which may be enough to help make decicions, recognizing that these analyses are only a visual approximation to tone.
For pot tapers i like the effect oc a standard log pot with a treble-bleed resistor and cap, which slows and smoothes the taper. For tone pots, a higher value is brighter, but with less control in the low range. I quite like a no-load pot which goes to infinite at 10. You can test the relative effects of these options witb the spreadsheet.
Good luck
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