Here are Bode Plot Generators for Guitar Freq Response

[rjb]

Hi All,

I’m posting this in both the Guitar Tech and Pickup Makers sections.

Here are two Excel worksheets I developed to model the frequency response of a pickup installed in a guitar and plugged into an amp. These are one-trick ponies, not all-purpose circuit simulators. You plug in the pickup’s DCR and inductance, the tone cap, volume & tone pot values and settings, cable capacitance, and amp input resistance – and Excel (almost) instantaneously generates plots of output amplitude & phase vs. frequency.

It would be a relatively simple matter to expand these worksheets to model a 2-pickup “Les Paul, ES-335, etc.” configuration. But I am not likely to do that until I personally need such a tool. If you want to, have at it.

I used to use NI MultiSim for this kind of thing, but ran out of ways of sneaking around the 30-day free trial period. Can anyone recommend another free circuit simulator with relatively easy learning curve?

Thanks,
-rb

GuitarBode(Standard Wiring).xls
GuitarBode(50s Wiring).xls

[marku52]

LT spice is a great free spice sim, tho I have to confess, I've never gotten a spice sim to match pickup resonance behavior, it's just too distributed to be well handled in a lumped sim.

Linear Technology - Design Simulation and Device Models

[rjb]

LT spice is a great free spice sim, Linear Technology - Design Simulation and Device Models

Thanks for the lead; I'll have to check out LT Spice.

tho I have to confess, I've never gotten a spice sim to match pickup resonance behavior, it's just too distributed to be well handled in a lumped sim.

Then I guess you'll have no use for my spreadsheets. They're pretty lumpy- based on Lemme's first-order approximation, with no consideration of eddy currents, AC resistance, etc. Just something for neophytes like me to play with. Oh well.

Thanks,
-rb

[LVS]

Simetrix Intro might be another good candidate to consider. Some years ago I was looking for a circuit simulator and noticed Rod Elliott recommended this one at his website. Versions keep improving - including the circuit editor, which I find quite user friendly and enables you to design and test a passive guitar circuit from nothing in a very short time. The free version permits just a limited number of components, but still enough for guitar and most stompbox sized stuff. I just regret the absence of a log potentiometer model, and work around it by applying logarithmic data to the linear model.

I agree that a spice simulation will only be as truthful as the models used (lies, damned lies and spice), but still, it can provide some valuable insights on the influence of components surrounding a pickup, and save time too as a pre-soldering test stage. That's just my humble opinion.