Tone caps for EMG

[Tinderwet]

I have a pair of EMG HA pickups in my Ibanez. Since I rarely if ever used the tone knob, and there's no room to install any of the active tone systems in the guitar, I was wondering if I could just change the stock .1u capacitor to something smaller for a certain effect. What I would like to achieve is a roll off at around 2 - 2.5kHz, just below the resonance of the pickup (listed at 3.75kHz), so I could have another usable tone at hand. Is there any way to calculate this? Also, I guess in the case of EMGs, the tone circuit doesn't form a resonant peak when rolled off fully, because it doesn't interact with the inductance of the pickup, so it's simply a first order low pass filter. Am I right about that?

Thanks!

[Mike Sulzer]

I have a pair of EMG HA pickups in my Ibanez. Since I rarely if ever used the tone knob, and there's no room to install any of the active tone systems in the guitar, I was wondering if I could just change the stock .1u capacitor to something smaller for a certain effect. What I would like to achieve is a roll off at around 2 - 2.5kHz, just below the resonance of the pickup (listed at 3.75kHz), so I could have another usable tone at hand. Is there any way to calculate this? Also, I guess in the case of EMGs, the tone circuit doesn't form a resonant peak when rolled off fully, because it doesn't interact with the inductance of the pickup, so it's simply a first order low pass filter. Am I right about that?

Thanks!

I think what you are saying is right. If the schematic here (Active Pickups? How do EMG do it? | La Révolution Deux) applies, then at least that model has a 10K output impedance, and you can compute the roll off effect of a particular capacitor value based on that, if that is standard on all similar models. But you are going to need to adjust the exact value by listening in any case.

[Tinderwet]

I think what you are saying is right. If the schematic here (Active Pickups? How do EMG do it? | La Révolution Deux) applies, then at least that model has a 10K output impedance, and you can compute the roll off effect of a particular capacitor value based on that, if that is standard on all similar models. But you are going to need to adjust the exact value by listening in any case.

Thank you very much, Mike. I tried 2.7nF, but it didn't do a single thing. lol I think I see my error now. I calculated with the 25k tone pot and the 10k output impedance added together, instead of just the 10k impedance alone, which the cap sees when the pot is being turned down fully. I guess I should try 6.8 or 8.2nF or even 10n.