Active Electronics and Battery Power Consumption

[edbnuts]

Hello everyone,

Possibly a silly and/or obvious question but after a quick search and I'm still not certain after reading two of the returned threads. Will the 9v (or two 9 volt batteries) drain quicker solely by keep the volume knob dimed (with the tone knobs flat)? If so, does it then follow that the battery(ies) drain even quicker with the tone knobs boosted as well? I think you can see where I'm going here. Actually, have a few questions concerning how exactly tone knobs work so if someone can direct me to a good on board tone control information source that'd be appreciated.

Thanks in advance,
Ed

 

[Wfrance3]

I don't know for sure, but wanted to let you know that I've owned a few basses with a preamp and found that leaving them plugged in for an extended period of time is probably going to be a bigger power drain than where the volume and tone knobs reside. I also believe that in most basses 18v. will give you more headroom, and may even last longer. For me, I just play the bass at the tone and volume setting that works best and let the chips fall where they may. I've never had an 18v. setup, but always check my 9v. every 6 mos. If you have a few that need a battery, it's a good idea to check in June and in December. Easy to remember. Batteries in a preamp tend to last a really long time, so that's always been plenty for me, unless I know I goofed and accidentally left my bass plugged in all night after practicing or something. I'm pretty conservative, so if a battery ever tests less than 9v. it gets changed. For me it's good policy and keeps me from ever getting caught unawares.

The EQ question can be searched out. I get good results searching using just Google. If you like a different search, it would probably work as well. I just type something like - Talkbass preamp eq.
The first few returns will always be from TB, which is a really good and well organized resource.

I will add one more thing b4 I let you go, not all preamps are created equally, some have boost only, some have boost and cut, it really depends on your specific preamp of interest. You will probably get more useful info if you ask about the characteristics of a specific brand and model of preamp. There are lots of 'em out there. Good luck!

 

[RobbieK]

Yes and no. The positioning of the pots won't increase or decrease the current consumption of your preamp. However the higher your active boost is set, the faster you'll run out of headroom. If your bass has its volume pot wired before the preamp input, the same can be said of that control.

IOW, if you start to hear some clipping creeping in, then backing of the controls might get you through the set but it's time for a new battery.

Personally I test the battery voltage from time to time. If it's below 7v I change it. You can get simple digital multimeters these days for under 10 bucks. Get one for your gig bag...

 

[Wfrance3]

You can get simple digital multimeters

There is this little gizmo as well:

What I like about it is it's as easy to check your battery as it is to plug in your bass.
One caution tho - I had a fretless with an east preamp in in it once that it wouldn't check. Had to pull the battery and use the little contact points on the outside of the meter instead of just being able to plug the meter into the output jack on the bass. Not that big a deal really. - It's been a while back, but I do recall searching TB to see what I could learn. I found a thread, that said, basically, that's the way it goes sometimes... FWIW, I had a different John East Preamp in a different bass and it worked just fine using that same meter, plugging it in to check the battery.

 

[RobbieK]

Yep for sure. You can use a stereo jack with a multimeter for testing the battery voltage while it's still in the bass. I have a home brew version of that gadget too. I shot a video about making it, but haven't uploaded it for various reasons. In the near (ish) future I'll upload a vid about this.

You are right. Testing the voltage like this won't work with some instruments. For whatever reason, some circuits don't have the negative side of the battery going to earth. So instead of the old "battery negative to the ring of a stereo jack" trick, they use a switching jack.