Actives Unveiled.

[NavyBass]

This thread will erase all misconceptions of active pickups and active EQ's.

Let me start by saying that they are NOT the same.

Active Pickups: These pickups have a small pre-amplifier built in to the pickup. They are low impedance, and require a battery to work. Examples are EMG. The way to tell if you have Active Pickups is that your pickup will have a wire going from the pickup to the battery. Active pickups can not be made passive. If the battery dies, no sound will come from the bass

Active EQ's: This is a tone circuit that will usually have either Bass and Treble controls or Bass, Midrange and Treble controls. They also require a battery to work. They can be used with Active or Passive pickups. When you are using passive pickups, the circuit can be modified to bypass the EQ so you can run the bass passive and some basses already come with this. With this option if the battery dies, you can still play the bass with a flick of the bypass switch. Examples of basses with active EQ's and passive pickups are Stingrays, G&L L-2000's and ASAT's.

Passive Tone Circuits: Think original Fender Jazz or Precision Basses. The tone control is just a capacitor that acts as a low pass filter and filters the high frequencies to ground.

Passive Pickups: Again the original Jazz and Precision basses. These pickups do not require a battery to run.

[PaulSimonon]

Nice JP! I know most people don't believe me when I tell them active pickups have their own small pre-amp in them, so if they doubt me, they need to come here! I still want you to post some schematics, so I can mess around with it.

[PaulSimonon]

I had another really good link that got pretty in depth as well, I'll try to dig it up, I read it in my book....

http://www.buildyourguitar.com/resources/lemme/index.htm

[fltlnbassist]

what about the Ibanez SR305DX it has like "phat boost" is that active Eq?

[NavyBass]

what about the Ibanez SR305DX it has like "phat boost" is that active Eq?

It's a bass boost. All it does is boost the bass frequencies a bit.

[good rats]

Simple but effective. :thumb:

[edgebass5]

One thing to note, you listed EMG as being a typical active pickup. That's true for all of their pickups except the HZ line, which is a passive pickup.

[NavyBass]

One thing to note, you listed EMG as being a typical active pickup. That's true for all of their pickups except the HZ line, which is a passive pickup.

True.

Good Catch. :thumb:

[peeted]

do active eqs have preamps?

[edgebass5]

do active eqs have preamps?

Yes they do, in fact, they are a preamp. Another name for an active EQ is onboard preamp.

[peeted]

can anyone explane what an ajustable pre amp is pleese?

[edgebass5]

^^^I would think that any preamp would be adjustable to some degree. Can you elaborate?

[NavyBass]

The preamp in the Elite Precision basses was just a preamp. It didn't have any eq adjustments on it. It essentially just boosted the output of the bass.

I've still got one of those preamps in my parts drawer. It just had an input and an output, no controls at all. The controls on the bass (volume & tone) were passive.

[peeted]

well mines got a swich for active/passive, pickup volume, active highs and active lows but on the back its got a hole in the panal were u can stick a screw driver in, its labled ajustable preamp and it says l on one side and h on the other, what is it?

[edgebass5]

^^^That sounds to me like a variable gain trim. Bill Bartolini uses them a lot. It adjusts the output of the onboard preamp, so that you can match it up with the input of your amplifier, or you can use it so that there is no noticeable jump or drop in volume when you switch from active to passive and vice versa.

[peeted]

cool, thanks