How emulate passive PU + tone cap resonance with active PUs

[Marco Pancaldi]

Hello,
I love very much the "completely close" tone of certain pickups, for example using a jazz bridge PU with a .022 tone cap end zeroed tone knob to obtain a smooth-middle resonant tone in a fretless. It's obvious that the same is not possible with a buffered PU (ex. EMG active) where the pot + cap network can give a progressive hi rolloff but not the resonance with the (in this case isolated) coil.
Is there a simple passive (cap + inductance?) network that can be implemented (and fine tuned changing some cap values) without the need for an active resonator filter?
There's an intresting hint from Jack Orman here: Guitar Pickups Simulation, but I'd wish to maintain the low impedance (but low Z = big C and I values...), and this kind of inductor (a little transformer) is bulky and always a potential noise source.
Ideas?
Thanks
m.p.

[charrich56]

Marco,

There are two approaches you could use. One would be to use an active filter. One off the shelf example would be the EMG VMC circuit which of course works perfectly well with EMG active pickups.

Jack Orman's approach would work fine but think of it as converting the active pickup back to passive and then getting back all the disadvantages of passive pickups. That's OK of course if it works for you and produces the tone you want.

At the amplifier end feeding a high Z input it should be OK, or if you want it on the instrument, you can try feeding a buffer pedal then sending it to the amp. Electrical noise won't be a significant issue if the subminiature transformer is in a shielded control cavity or in a grounded metal box, but the transformer could pick up magnetic field noise under some circumstances. Overall it's worth trying partially because it's so inexpensive (the transformer is about $3.00 US) and can give good results.

[Mike Sulzer]

Why use a pickup with a built in active buffer? Use a separate active buffer (a JFET source follower, for example), and then set the resonance with a C (or different Cs on a switch, or ch..56's continuous boot strap C adjust) right across the pickup. Adjust the resistive load as required. And if the standard type tone control is what you like, you can put that there, too.

Hello,
I love very much the "completely close" tone of certain pickups, for example using a jazz bridge PU with a .022 tone cap end zeroed tone knob to obtain a smooth-middle resonant tone in a fretless. It's obvious that the same is not possible with a buffered PU (ex. EMG active) where the pot + cap network can give a progressive hi rolloff but not the resonance with the (in this case isolated) coil.
Is there a simple passive (cap + inductance?) network that can be implemented (and fine tuned changing some cap values) without the need for an active resonator filter?
There's an intresting hint from Jack Orman here: Guitar Pickups Simulation, but I'd wish to maintain the low impedance (but low Z = big C and I values...), and this kind of inductor (a little transformer) is bulky and always a potential noise source.
Ideas?
Thanks
m.p.

[charrich56]

Sorry, I had misread the post where you had indicated you don't want an active filter. The easiest way as Mike indicated is to do what you want to passively with a capacitor/resistor network, or conventional tone control, then use an onboard buffer. If you want an easy drop-in buffer solution without having to hack much electronics. , the Creation Audio Labs "Redeemer " is a high quality, not expensive, and easy to install unit.