Active vs passive eq?

[pattyløve]

Sorry if this has been done before but i have searched with no find.

When reading about certain amps, i notice some have an active eq and some have passive. Ive even played a few that have had both.

My question is, what is the difference between these? Is there a better one or is it more of a taste thing?

 

[Got2SadowskyNYC]

Active EQ's require a battery this is what makes it "active". These have the ability to boost and cut frequencies. This is at least treble and bass, but some pres have a mid freq. that may or may not be selectable.

Passive EQ's do not have a battery. These are NOT called "eq", but tone control. This is usually a high freq. roll off or cut ONLY. These do not require a battery to function. Classic Fenders are an example of passive tone control.

My Sadowskys are active AND passive. They require a battery and have boost only Bass and Treble, but I can switch it to passive and use a "vintage tone control". In passive mode I can remove the battery completely.

 

[Projectile]

Active EQ's require a battery this is what makes it "active". These have the ability to boost and cut frequencies. This is at least treble and bass, but some pres have a mid freq. that may or may not be selectable.

Passive EQ's do not have a battery. These are NOT called "eq", but tone control. This is usually a high freq. roll off or cut ONLY. These do not require a battery to function. Classic Fenders are an example of passive tone control.

My Sadowskys are active AND passive. They require a battery and have boost only Bass and Treble, but I can switch it to passive and use a "vintage tone control". In passive mode I can remove the battery completely.

The OP is talking about an amp EQ, not one on a bass guitar. I've never seen a battery powering an EQ in an amplifier. There certainly are fully passive EQs, and they aren't called "tone controls."

Passive EQ tends to be more transparent, since they only allow you to cut frequencies rather than boost. They aren't as flexible, though.

EDIT: Here's a decent article with all of the gory details:
http://www.soundonsound.com/sos/jul07/articles/qa0707_4.htm

 

[Passinwind]

Sorry if this has been done before but i have searched with no find.

When reading about certain amps, i notice some have an active eq and some have passive. Ive even played a few that have had both.

My question is, what is the difference between these? Is there a better one or is it more of a taste thing?

http://www.talkbass.com/forum/f15/some-discussion-amp-eqs-950782/

 

[Got2SadowskyNYC]

You know how your brain will fill in holes or word skip. That's what happened. I completely missed the amp part.

That being said, the principle is the same. Actives boost/cut and have other options. Passives cut (filter) freqs. only.

The transparency statement is subjective and depends on the pre. Some amp eqs are not designed to be transparent this is , in part, where their character (color) comes from. For example, put a transparent EQ in an Ampeg and it will not sound like an Ampeg.

I personally prefer transparent pres, amps and cabs. My pre is active.