Looking for Resonant Peak Frequency of Legacy Bridge Pickup

[senskin]

Hi to all,

I would like to experiment with capacitators parallel to the bridge pickup of my Legacy to lower the resonant peak (frequency) and change the sound of the pickup. Unfortunately no specs are published on official G&L pages nor are they to be found in the knowledge base. Does anybody have information on that? And maybe for Comanches and S-500 also? Are there any diagrams available which let you estimate the relative height of the peak?

Thanks

Matthias

[Craig]

Hi to all,

I would like to experiment with capacitators parallel to the bridge pickup of my Legacy to lower the resonant peak (frequency) and change the sound of the pickup. Unfortunately no specs are published on official G&L pages nor are they to be found in the knowledge base. Does anybody have information on that? And maybe for Comanches and S-500 also? Are there any diagrams available which let you estimate the relative height of the peak?

Thanks

Matthias

I sent your post to Paul Gagon, G&L's VP of Engineering, here is his reply:

Hi Craig,

Publishing specs on the Resonant Peak Frequency of our pickups would have to be accompanied with a pretty detailed explanation on how we tested them,
what they were connected to and how you calculate their resonant point. However, let's see if we can shine some light on the topic. We are going to touch on
the technical stuff very lightly and paint with a broad stroke. OK, Using an inductance meter we can measure the inductance of any of our pickups. Let's look
at our Legacy pickup. The inductance of our Legacy pickup is right around 2.6H (Henries). The formula for calculating resonant frequency is 1 divided by 2Pi (6.283)
times the square root of the product of the coil inductance (In Henries) and any capacitance (In Farads) across the coil.

The formula looks like this 1
Fr= -------------
2Pi*(Square root of Inductance * Capacitance)

So let's say you have a Legacy pickup (2.6H) and a .001uf (.000000001 Farad) capacitor across it. Where would the resonant frequency be. Using the equation above
we get approximately Fr=3.1KHz. If I use a .0022uf cap across the pickup I would get Fr=2.1KHz. You can do these same calculations for an S-500 pickup which has an
inductance of 3.3H.

There are so many other parts to this answer but it's kind of beyond the scope of a simple email. Basically, the capacitance that a Legacy pickup sees with the volume and
tone at max are the sum of the distributive capacitance of the coil (50pf) the guitar cord going to the amp (300pf to 500pf) and the input capacitance of either your first pedal
or amp (around 150pf).

Sorry for such a confusing answer but I think you can see that having a chart to tell you Resonant Frequency without a whole bunch of other information would not be very accurate.

Thanks Craig,
Paul

Hope this helps.

[senskin]

Craig,

thank you so much for forwarding my question. You really know where to find answers! Great! So I will start with a 0,0022 uF cap , see how it turns out to sound like and go further step by step if necessary. Certainly the capacity of the cable plays an important role but for finding the appropriate capacitator I will use one single cable only so this will be a constant.

Thanks again,

Matthias