turn passive pickups into active ones

[AgentTwitch]

I have a basic understanding of the way a passive pickups and and active pickups work. I was wondering if anyone has any links or helpful ideas on how to make a passive pickup (example being Screamin Demon) and turning it into an active one. Are there any real benefits of doing this?

Oh, and lest I forget, I have been creeping in the shadows for some time, I really like the tutorials section and this forum! Keep up the good work!

[daveq]

Yes, it can be done. Active pickups usually use a lower output from the physical pickup than a passive like the demon. I think the main reason for this is noise reduction. So starting out with a higher output as a building block may put you at a disadvantage. You would also need to find a place to put the electronics. Maybe route a deeper pickup cavity and place them underneath? You could always do the electronics in the control cavity if you didn't mind that.

So I think what you would end up with is a higher noise pickup than something like the EMG's, but you could try to filter it with your electronics (sacrificing some of your dynamics).

I know there's at least one good site on the web for building your own pickups. If I remember it, I'll pass it along. I bet there are many people who have tried doing this.

[AgentTwitch]

I was thinking about routing below the pickups. I know that there are some signal filters that can be added, I have seen them used in computer mods.

[funkle]

I think the main difference between an active and a passive PU is that the active pickup coil has a much lower impedance (and lower output), and utilizes electronic amplification to increase the signal in the PU itself prior to sending it through the cable to the amp. You can make a passive PU "active" by adding a preamp, but the PU will still differ from a true active because the coil is high-impedance (more windings). So you'll gain some, but not all of the characteristics of a true active PU.

There is a F.A.Q. at Warmoth that sums it up pretty well. It's talking about basses, but the concept is the same.

-Sven

[daveq]

funkle - I think we basically said the same thing, right (see my comments above)?

Using a higher output pickup for an active pickup will result in a bit noisier pickup - but you can still add filters, EQ, ... to get your sound. You'll just be losing one of the nicest features of an active pickup - very low noise.

[DividedByJames]

fyi funkle is refering to this page. Also Carvin makes passive pickups and then connects them to an active system. Check their webpage.

Otherwise Seymour Duncan will custom make a pickup for you (I think for $125)--just specifiy a Livewire Screamin Demon.

[MikeB]

it can be done easily, i really dont wanna sound like a know it all, but ill say how it can be done.

basically replacing the volume control on the guitar with a simple circuit built around an op-amp, i use the TL-082CN ultra low noise ones, anyhow these can be used as pre-amps, or signal attenuators. there is a configuration to allow the gain to be 1 (ie no boost) and the volume to be controlled as normal, ie the knob turns guitar down, (gee whiz mike, a circuit for no reason, please let me route out my nicec guitar for that you say, lmao) it does have a reason the output from the op-amp is low impedance, so it will drive a long transmission line without much treble roll-off and also drive line inputs etc... the impedance is low because it doesnt use a passive control to adjust the volume, so no resistor there to raise the impedance...

if you are interested im sure i could draw you up a circuit with component values etc... just e-mail me or something to let me know!

hope this isnt a brain pickler!!

mike