Number of battery boxes for a "full active" setup?

[tbassist4]

If I'm going to put two active pickups and a preamp into a build, how many battery boxes would this require? Will this really require three 9v batteries? And potentially a whopping six if I wanted everything at 18v? How is this usually done?

[bassgod0dmw]

It would be one or two...
One for 9v
Two for 18v

What are you planning on running?

[MetaMarmot]

Under the assumption that your pickups and preamp aren't going to draw a large amount of current, you should be able to wire one 9V (or two 9V in series for 18V) and connect it as the power source for the pickups and the preamp.

[T-MOST]

Or one double box that flips open batts separately.

[tbassist4]

I was planning on running two EMG 35DCs and a preamp. I was under the impression that each pickup requires 9v, and the preamp requires 9v as well. Will the current draw of all three together be above 500mA?

[line6man]

Originally Posted by tbassist4

I was planning on running two EMG 35DCs and a preamp. I was under the impression that each pickup requires 9v, and the preamp requires 9v as well. Will the current draw of all three together be above 500mA?

Where on earth are you getting 500mA !?

Those components individually draw between less than 100uA and a couple of mA.

[line6man]

Originally Posted by tbassist4

If I'm going to put two active pickups and a preamp into a build, how many battery boxes would this require? Will this really require three 9v batteries? And potentially a whopping six if I wanted everything at 18v? How is this usually done?

One battery for 9V, two batteries for 18V.

There is absolutely no need to have batteries for each active component.

[tbassist4]

Originally Posted by line6man

Where on earth are you getting 500mA !?

Those components individually draw between less than 100uA and a couple of mA.

From my poor understand of electronics. I just did a little google and wikipedia work and I understand it now. I'm not stupid, just ignorant.

Originally Posted by line6man

One battery for 9V, two batteries for 18V.

There is absolutely no need to have batteries for each active component.

Great - so with the current draw for two active pickups plus a preamp being around 2mA combined, a standard 9v battery will last around 87.5 hours before getting to the cutoff voltage of below 4.5v, right? I hope...?

[line6man]

Originally Posted by tbassist4

From my poor understand of electronics. I just did a little google and wikipedia work and I understand it now. I'm not stupid, just ignorant.




Great - so with the current draw for two active pickups plus a preamp being around 2mA combined, a standard 9v battery will last around 87.5 hours before getting to the cutoff voltage of below 4.5v, right? I hope...?

4.5v is far too low to run pickups and preamps at. I'm also not sure where you are getting such a precise measure of battery life if the only known factor is current draw.

The battery should last quite a long time. If you're paranoid, you can change it every 6 months to a year.

[tbassist4]

Originally Posted by line6man

4.5v is far too low to run pickups and preamps at. I'm also not sure where you are getting such a precise measure of battery life if the only known factor is current draw.

The battery should last quite a long time. If you're paranoid, you can change it every 6 months to a year.

EMG listed 4.5V as the cutoff - I'm just going by the books here. I'm also not paranoid - just new to active electronics and I just wanted some ballpark numbers, that's all. It really wouldn't concern me even if for some odd reason I had to change batteries monthly - those kinds of things don't bother me.

Just trying to understand, that's all.

[grendle]

A 9v should last about 3-6 months or more depending on how much you play and if you leave the bass plugged in or not. One 9v is fine but Emgs really come alive with 18v . 1 or 2 batteries total system that's all. Go to emg.com and look at the wiring pdf.

[SGD Lutherie]

I'd use two batteries and run them on 18V. They sound better that way. The batteries should last you 6 months at least.

Back when I used EMGs I would often forget to unplug the bass for days on end when it was on the stand at home. Never had a battery go dead on me.

[line6man]

Originally Posted by tbassist4

EMG listed 4.5V as the cutoff - I'm just going by the books here. I'm also not paranoid - just new to active electronics and I just wanted some ballpark numbers, that's all. It really wouldn't concern me even if for some odd reason I had to change batteries monthly - those kinds of things don't bother me.

Just trying to understand, that's all.

I've found a lot of things on various EMG spec sheets to be quite questionable.

If you look at the spec sheet for that pickup, for example, they also claim a 4.5V peak output! Aside from being absolutely ****ing absurd, there is no way you can conduct with a supply voltage equal to the signal voltage.

The current rating should be accurate, however.
EMGs do use low-power opamps whose current draws can be reasonably close to what EMG claims, and you can check the current draw with a multimeter, too.

[SGD Lutherie]

Originally Posted by line6man

If you look at the spec sheet for that pickup, for example, they also claim a 4.5V peak output! Aside from being absolutely ****ing absurd, there is no way you can conduct with a supply voltage equal to the signal voltage.

That would be an awfully large DC offset!

[tbassist4]

Originally Posted by grendle

A 9v should last about 3-6 months or more depending on how much you play and if you leave the bass plugged in or not. One 9v is fine but Emgs really come alive with 18v . 1 or 2 batteries total system that's all. Go to emg.com and look at the wiring pdf.

Originally Posted by SGD Lutherie

I'd use two batteries and run them on 18V. They sound better that way. The batteries should last you 6 months at least.

Back when I used EMGs I would often forget to unplug the bass for days on end when it was on the stand at home. Never had a battery go dead on me.

Great! Thanks for some real world numbers. That's plenty long enough, and I'm glad I won't have to use an array of batteries. A double box for 18v sounds lovely to me.

[Rob22315]

If you want, you can run your active bass without any batteries. A wiring trick will let you run your bass from a wall wart, either 9 or 18v.