When Is The Battery "On" w/Active PUs?

StyleOverShow · #1 09-03-2009, 01:30 AM

Okay, so I mostly play an active MM Sterling, my bass of first choice for anything not 'straight ahead jazz'. I carry a couple of 9 volts with me as a professional should.

I also unplug my bass as I have thought that the battery is 'on' if the circuit is closed with a quarter inch in the jack and the active controls engaged.

Is that true? When is the battery on with active basses, and more importantly, when is it off?

Thanks for your thoughts.....

-richard

**TheMutt** · #2 09-03-2009, 01:41 AM

For most active basses, the circuit is closed when there is a cable connected to the output jack. The shield conductor on the cable completes the circuit between the preamp and the battery. You could always add a small on/off toggle switch to disconnect the battery lead from the input jack. I'm doing something similar to this on my SR5.

**line6man** · #3 09-03-2009, 08:00 AM

The battery switches on when a cable is inserted into the jack.

The negative terminal of the battery connects to the ring terminal of the output jack.
As you know, a standard mono guitar cable does not have a ring terminal, and the sleeve terminal extends into what would be the ring portion on a stereo cable.
When you insert a mono cable, that causes the ring terminal to short out to the sleeve (ground) which connects the negative terminal of the battery to ground, which completes the circuit for the active electronics.

StyleOverShow · #4 09-03-2009, 09:01 AM

So, cable in, battery on. Disconnecting when not playing is a good idea to extend battery life.

Thanks for your technical explanations.

lug · #5 09-03-2009, 09:28 AM

Quote:

Originally Posted by line6man

The battery switches on when a cable is inserted into the jack.

The negative terminal of the battery connects to the ring terminal of the output jack.
As you know, a standard mono guitar cable does not have a ring terminal, and the sleeve terminal extends into what would be the ring portion on a stereo cable.
When you insert a mono cable, that causes the ring terminal to short out to the sleeve (ground) which connects the negative terminal of the battery to ground, which completes the circuit for the active electronics.

This should be a sticky.

(b)Assman · #6 09-03-2009, 09:39 AM

Just leave your cable in over-night or an for an extended period and you'll figure it out right quick :P

JTE · #7 09-03-2009, 09:47 AM

BTW, your MM doesn't have active pickups. The PUPs are passive, but the EQ circuit after the PUPs is active. Yeah, on EB Music Man and most other instruments the 1/4" output jack is a TRS. The ring connects to ground when you plug in a mono plug, That completes the circuit and turns the battery on.

Pre EB StingRays didn't have that though- the battery drain was so low that Leo didn't think it was important. My experience with active basses is that unplugging them when not playing (I unplug if it's not going to be played for an hour or more, so I don't unplug at gigs between sets) my DuraCell® batteries last at least a year. I've never had one fail on stage except when I used an Eveready® alkaline.

John

**line6man** · #8 09-03-2009, 10:14 AM

Quote:

Originally Posted by JTE

BTW, your MM doesn't have active pickups. The PUPs are passive, but the EQ circuit after the PUPs is active.

Ah, I just noticed that in the title of the thread.

I have said this several times this week now (*sigh) , but 90% of the time, "active bass" means passive pickups with an active preamp. Very few pickups on the market are active.
Pretty much only EMG and MEC come to mind.

Furthermore:

The battery is always on... It's the electronics that turn on and off, not the battery itself.