Preamp for active pickup?

[abarson]

I'm a bit confused with some of the stuff I've come across on the 'Net.

I've always understood "active pickups" to be a pickup with its own embedded preamplifier. An example would be an EMG 35J. If this is so, then why are there vendors who market separate preamplifiers for active pickups?

If I want to add a preamplifier to a pair of passive pickups, what do I need to look for? Can you use a preamp for active pickups with passive pickups? Is there something special about its input impedance?

[badboy1984]

You can add preamp on both passive and active pickup. Some preamp doesn't go well with certain active pickups.

Pretty much all passive pickup can hook up a preamp.

[CrashClint]

I think Audere makes a preamp that will work with active pickups, but not 100% sure.

[DavidRavenMoon]

Originally Posted by abarson

I've always understood "active pickups" to be a pickup with its own embedded preamplifier. An example would be an EMG 35J.

That's correct. Some active pickup systems don't have the preamp inside the pickup, such as Alembic and my own active pickups, but that's the most common way to do it.

Originally Posted by abarson

If this is so, then why are there vendors who market separate preamplifiers for active pickups?

Before there were "active pickups" such as EMG's (I'm leaving Alembic out of this at the moment) there were some onboard or external preamps that offered active tone controls, and better frequency response from the pickups by isolating them from the cable and amp through buffering, whereas the preamp has a high impedance input, and a low impedance output.

So the reason you might want to use a preamp with active pickup is for tone control. Passive tone controls can only cut, while actives can cut and boost.

The preamp in the active pickups is mainly to boost the level if the pickup is made with fewer windings for a wider/flatter response, or for some tone shaping and noise reduction as on an EMG.

Originally Posted by abarson

If I want to add a preamplifier to a pair of passive pickups, what do I need to look for? Can you use a preamp for active pickups with passive pickups? Is there something special about its input impedance?

There are many preamps for passive pickups, each offering something slightly different in the way tone controls, etc.

I'm sure you'll get a lot of opinions here on various options.