Do active pickups drain batteries?

[PattiMichelle]

I noticed that the 9V lead goes directly to the Bartolinis, and that the ground side is directly grounded (via the audio inputs). So the amp jack doesn't interrupt the battery current as it does for the Audere preamp - the active pickups are always on! Is this standard for active pups? Doesn't it drain the battery?

[line6man]

The negative terminal of the battery should be connected to the ring terminal of the output jack so that the power is only on when a guitar cable is plugged in.

[PattiMichelle]

With the Audere preamp, the black battery wire goes there (to the ring) so the battery gets turned on for the preamp when the cable plug is inserted, like you say. If I connect the ground of the active pups to the ring, they'd be connected to the black wire, and they're *always* connected to the red wire - so the active pickups are always "on," whether or not the plug is inserted, even though the pre is turned on and off by the plug insertion.

http://www.audereaudio.com/Classic_Install.pdf

[line6man]

Originally Posted by PattiMichelle

With the Audere preamp, the black battery wire goes there (to the ring) so the battery gets turned on for the preamp when the cable plug is inserted, like you say. If I connect the ground of the active pups to the ring, they'd be connected to the black wire, and they're *always* connected to the red wire - so the active pickups are always "on," whether or not the plug is inserted, even though the pre is turned on and off by the plug insertion.

http://www.audereaudio.com/Classic_Install.pdf

Ground the pickups normally.

If the negative terminal of the battery is going to the ring terminal of the output jack, the battery will only be connected to ground when a mono guitar cable is inserted, and thus the circuit will only be receiving power when the bass is plugged in.

You do not ground the pickups to the ring terminal, they get grounded to the sleeve.

[PattiMichelle]

Silly me - Many Thanks!!!! <= (this forum needs a blush icon)

[StyleOverShow]

Damn, I'm blushing just looking at your toon of yourself.

Back to the topic, I unplug when not in use to preserve batteries.

[countrybass007]

My active basses eat batteries if they're left plugged in.

[4StringTheorist]

The overwhelming majority of Bartolini pickups are passive.

An active preamp or active pickups will be on and draining the battery if the plug is in the jack. (Assuming everything is wired correctly)

[PattiMichelle]

Originally Posted by 4StringTheorist

The overwhelming majority of Bartolini pickups are passive.

I was really surprised, too - but I verified that the GT-7 has active pickups. I got it wired right and working tonight - thanks for the help! I guess I didn't do the shielding too well - it's real quiet until I bring my fingers within 1/4inch of the pickups, then I can hear a slight bit if hum, which stops when I touch the strings. So I guess the pickups need a fatter ground wire? I've got all the grounds going to the same place on the copper foil lining the pot cavity - and from there to the sleeve on the input jack. I *think* that's supposed to be optimal. I'll be glad when all this is done!

[line6man]

Originally Posted by PattiMichelle

So I guess the pickups need a fatter ground wire?

Where were you getting the notion that a larger gauge of wire would have any effect on anything?

[PattiMichelle]

Well, you know, lower resistance - better grounding? Just guessing, really. Too, I figured it must be *my* fault (as the person that installed the preamp) that when I rest my thumb on my neck Bart while playing, there is a little bit of hum - Barts are supposed to be quite high quality, right? I was very careful to ground everything (pups, jack, preamp) to *one* spot on the copper foil enshrouding the electronics cavity thereby avoiding ground loops... Still, the GT7 is a very nice unit!

[line6man]

Originally Posted by PattiMichelle

Well, you know, lower resistance - better grounding? Just guessing, really. Too, I figured it must be *my* fault (as the person that installed the preamp) that when I rest my thumb on my neck Bart while playing, there is a little bit of hum - Barts are supposed to be quite high quality, right? I was very careful to ground everything (pups, jack, preamp) to *one* spot on the copper foil enshrouding the electronics cavity thereby avoiding ground loops... Still, the GT7 is a very nice unit!

FWIW, whatever you are reading about the star grounding method is nonsense.

The kind of ground loop you would get inside a bass is so insignificant that it's pretty much safe to say that you can't get a ground loop at all.

Ground everything to the nearest ground points and then just be sure that they can all interconnect in one way or another.

[bassbenj]

Originally Posted by PattiMichelle

I was really surprised, too - but I verified that the GT-7 has active pickups. I got it wired right and working tonight - thanks for the help! I guess I didn't do the shielding too well - it's real quiet until I bring my fingers within 1/4inch of the pickups, then I can hear a slight bit if hum, which stops when I touch the strings. So I guess the pickups need a fatter ground wire? I've got all the grounds going to the same place on the copper foil lining the pot cavity - and from there to the sleeve on the input jack. I *think* that's supposed to be optimal. I'll be glad when all this is done!

Not a fatter ground wire. Did you shield the pickup cavities? That usually helps. Of course you can't shield the tops of the pickups so you have to live with that. But usually of you have the kind of hum pickup you describe, the answer is to somehow ground the polepieces of the pickups if you can find them (under the pickups) With active pickups you may or may not be able to do this. In that case a pickup cavity shield is about the best you can do. (Until I put a pickup cavity shield on my G&L Tribute, I had a wire running from the bridge to a pole piece to kill the hum. Of course active pickups often don't use grounded bridges. I'd start with shielded pickup cavities and see what that does.

[PattiMichelle]

Originally Posted by bassbenj

Not a fatter ground wire. Did you shield the pickup cavities? That usually helps. Of course you can't shield the tops of the pickups so you have to live with that. But usually of you have the kind of hum pickup you describe, the answer is to somehow ground the polepieces of the pickups if you can find them (under the pickups) With active pickups you may or may not be able to do this. In that case a pickup cavity shield is about the best you can do. (Until I put a pickup cavity shield on my G&L Tribute, I had a wire running from the bridge to a pole piece to kill the hum. Of course active pickups often don't use grounded bridges. I'd start with shielded pickup cavities and see what that does.

I didn't shield the pickup cavities in the GT7 because they had solid copper backing on the bartolinis which was directly connected to the coax cables coming from the pickups, grounded to the copper lining the electronix cavity. I did fix the problem, tho - I opened the electronics cavity and added a wire from the ground side of the input jack to the copper foil I lined the cavity with. Now when I rest my thumb on the neck pickup - no hum!

One happy camper,
PattiM

PS: My Brice Z6 still has hum problems. That one has the pup cavities lined (bottom and sides) with copper foil and grounded to the copper foil in the electronics cavity - but always a small amount of hum. The strings are grounded but it doesn't help if I touch them with my hands, so I think the hum is coming from the pickups themselves as you suggest - maybe I need to find the pole pieces and ground them...