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Active Battery

#2
You can get a battery meter from Radio Shack. Or use a multi-meter. Just take the battery out and check it. If it gets to 8V or below replace it.

You can also use something like this:

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Normally you will hear when the battery is getting weak, as you start to get some distortion when you pluck hard. It never just dies.
 
#4
pickle said:
Hey guys, silly question. How do i know when the battery in my active bass needs changing?

I told you it was silly lol.
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Depending on the design of the circuit, you may start to hear notes breakup (distort) This starts with the lower, nore harshly struck notes and spreads before the battery is completely dead.

Other circuits aren't so friendly and have almost no symptoms before they just quit.

You kind of need to just get in the habit of changing it on some cycle. I change them very six months, but I never leave the basses plugged in. I think about 300-600 hours is typical for battery like.
 
#6
stflbn said:
Touch the 9v battery to your tongue. If it doesn't motivate you to remove it quickly then it should be replaced. (Your head will not explode, nore fingernails pop off)
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Not a good idea with alkaline batteries! That was a standard test for zinc carbon batteries though.

The easiest way is to pickup up a cheap battery tester. You can find them in a lot of places like Radio Shack. A cheap multimeter could be more handy for other things.

That Batt-O-Meter is the easiest, as you just plug it into your bass and it gives a reading of the batteries health.
 
#7
SGD Lutherie said:
Not a good idea with alkaline batteries! That was a standard test for zinc carbon batteries though.
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There shouldn't be any difference - same voltage, same resistance means same current. I've done the tongue test to both and didn't notice a difference. :hyper:

I don't know what the electrical resistance of saliva is though. Is there a huge difference in internal resistance between the two chemistries?
 
#9
If you have a DC voltage meter, you can plug a 1/4" stereo (tip - ring - gnd) cable into the output jack. Then measure the DC voltages across the contacts at the other end of the cable:

Ring to Gnd: Battery voltage
Tip - Gnd: 0 V, this is the signal from the pickups.
 
#10
Rob22315 said:
There shouldn't be any difference - same voltage, same resistance means same current. I've done the tongue test to both and didn't notice a difference. :hyper:
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Alkaline batteries produce more current, and when new, the voltage is often higher than zinc-carbon batteries or heavy duty batteries (zinc–chloride).

The energy density of a Zinc-Carbon battery is 0.13, while an Alkaline is about 0.5.

It certainly wont harm you, but you can get quite a zing with a fresh alkaline battery. It also only tells you if the battery has any charge, not how much.
 
#11
SGD Lutherie said:
Alkaline batteries produce more current, and when new, the voltage is often higher than zinc-carbon batteries or heavy duty batteries (zinc–chloride).

The energy density of a Zinc-Carbon battery is 0.13, while an Alkaline is about 0.5.

It certainly wont harm you, but you can get quite a zing with a fresh alkaline battery. It also only tells you if the battery has any charge, not how much.
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In this case, energy density and current capacity do not matter. It is purely a matter of voltage and resistance. The higher capacity battery will still supply the same amount of current for a given voltage across the same load. Voltage differences between chemistries are usually 0.2 to 0.5 volts. Not enough to make a real difference here. For fun, I measured a couple of batts - got anywhere between 8.9 and 9.6 volts.

The tongue test is sensitive to voltage so as the batt nears the end of it's life, you can tell. Until the batt nears the end, it's tough to tell.
 
#12
The battery meter test sgd suggests is great. When I change the battery I write the month and yr on it. If I start thinking maybe battery needs change cause cant remember when put new one in. I'll check the date. if its at least 4 months old will reevaluate wether or not it needs changing. Or simply pop new one in and listen for difference. If cant hear one I put the old battery back in. Longest Ive kept a battery in bass is just over 7 months. It didnt necc need changing. Sound change with new battery test was minor sound change. But went ahead and changed it since had been 7 months allready.

Normally I'll go ahead and replace the battery at around the 5 month mark. But I could have use for battery meter with all the stuff I got that uses batteries nowadays. So will prob start going by the battery meter test sgd suggested. Lol.
 
#13
Rob22315 said:
In this case, energy density and current capacity do not matter. It is purely a matter of voltage and resistance. The higher capacity battery will still supply the same amount of current for a given voltage across the same load. Voltage differences between chemistries are usually 0.2 to 0.5 volts. Not enough to make a real difference here. For fun, I measured a couple of batts - got anywhere between 8.9 and 9.6 volts.

The tongue test is sensitive to voltage so as the batt nears the end of it's life, you can tell. Until the batt nears the end, it's tough to tell.
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Yeah, but I change my batteries when they get to about 8 volts. You wont be able to tell that with your tongue. ;) It takes a dew seconds to check them on a meter.
 
#14
SGD Lutherie said:
Yeah, but I change my batteries when they get to about 8 volts. You wont be able to tell that with your tongue. ;) It takes a dew seconds to check them on a meter.
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For fun, I measured the resistance of my tongue, it's 1-2 megohms FYI. That is the same resistance as my hands. I guess saliva isn't very conductive or I have sweaty hands.
 
#15
I own a Musicman Stingray with an active circuit. Sometimes my batteries last for months but sometime they last only weeks. To my opinion this is to soon. Is it possible that there is a circuit failure or something else? Please don't come up with the advice to unplug the cable. That is what I do all the time.

The batteries I use are Duracell 9 volts. When they empty the batteries last for about a year in my tuner.

Question: is it possible that I have some kind of leakage or is there an other explaination to this problem.

Sincerely

Wim Mulders
 
#16
I always use duracell and hav had mixed lifespans, the ones bought online hav been shortest life and the ones bought in a shop hav lasted longest, they all hav use before dates and my guess is that the online retailers hav had stuff on the shelf for a long time as they buy in bulk but don't hav lots of shop outlets to get stock turnover...

I think if you had a short somewhere the bass would sound weird as well as draining batteries real fast?
 
#17
Wimku said:
I own a Musicman Stingray with an active circuit. Sometimes my batteries last for months but sometime they last only weeks. To my opinion this is to soon. Is it possible that there is a circuit failure or something else? Please don't come up with the advice to unplug the cable. That is what I do all the time.

The batteries I use are Duracell 9 volts. When they empty the batteries last for about a year in my tuner.

Question: is it possible that I have some kind of leakage or is there an other explaination to this problem.

Sincerely

Wim Mulders
Click to expand...
how old is the bass?

i faintly remember something to the effect that early MMs didn't even have stereo jacks, and the battery just stayed "on" all the time.
 

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