Active PU's

Re: Active PU's

With a simple circuit and light use, they can last for years. This is when corrosion could become a problem. Neglect.

Things rarely reach this point because, as the battery voltage reduces, the output and tone of the pickups deteriorate. Your ears will tell you that the bass is not sounding one hundred per cent. The battery is one of the first things to check.
 
Re: Active PU's

Years, well okay. How often do you replace your batteries? I was at a gig a few years ago, the bass player showed up late, set up, plugged in, and realized he had a dying battery, and then had to leave and drive around looking for a store that was still open at that time of night. Granted he should have had a spare with him, but that did make an impresson on me.
 
Re: Active PU's

I use 18v in all my basses, and the bass I use the most (~6hrs a week + some gigs) the batteries lasted 8 months. I just replaced them... it started with some noise, then in a matter of minutes my bass was dead.
 
Last edited:
Re: Active PU's

I switch mine annually for the most part, but always carry a couple spares in the bag.

My NS Design electric-upright goes through batteries much quicker; that's usually 5-6 months.
 
Re: Active PU's

Laziness, a failing memory and far too many guitars have forced me into the habit of writing the installation date on every battery when it goes into an active instrument. Thus, whenever I inspect the battery inside any instrument, there can be no doubt as to whether it is due for a change. Anything over twelve months old, I replace. The removed battery gets used during repair/modification jobs - either to quickly test a wiring harness or for working on a double locking vibrato bridge.
 
Re: Active PU's

I've yet to replace the battery in my bass. I got my MM a year ago. I should probably change the battery in it.
 
Re: Active PU's

The new Duracell 9V are good for 5yrs. Throw em in the case. Be prepared. lol
PC
 
Re: Active PU's

Oh...

I um... thinking about it, I literally haven't checked or changed probably since about 2009 in my active basses!

Actually, I don't know if I've even changed and checked the battery in a Musicman I got back in 2001... Still works, so I guess it's due, lol.

BUT, I did put a fresh battery in after installing active pickups in one of my first basses I got back after loaning it to a friend for over 15 years... This would have been 3-4 years ago, I think.

I used to be better about such things when I played out more as a younger guy, lol.
 
Re: Active PU's

Years, well okay. How often do you replace your batteries? I was at a gig a few years ago, the bass player showed up late, set up, plugged in, and realized he had a dying battery, and then had to leave and drive around looking for a store that was still open at that time of night. Granted he should have had a spare with him, but that did make an impression on me.

Yeah, not much of a pro there. Spare 9Vs are a staple, both for guitar and bass. Never know when your daisy chain cable will get a short and you're stuck loading 9Vs into your pedal board.

First off, to be pedantic, on most basses it's not the pickups that are active, it's the control board/preamp. There are true active pickups, underwound for a more even response with a small op-amp built in to boost the signal, but 9 times out of 10 an active bass is active because it has passive pickups run through an onboard preamp replacing traditional passive volume/tone circuits.

To actually answer the question, it depends on a lot of things:

  • The circuit design of whatever's "active" is key; some are real power hogs and might only last a couple of gigs on a battery, while others can be played several hours a day for weeks. Aguilar and Bartolini preamps are noted for their energy-efficiency; Yammie active basses OTOH are rather less so, though certainly still giggable.
  • Most basses use the jack as a switch for the battery power; with the plug out of the jack, the battery's disconnected, and an alkaline battery can hold its charge indefinitely in an open circuit. Plugged in, even silent, there will be some current draw through the transistors, so how long you have it plugged in, playing or not, is also a big determinant of battery life.
  • How hard you push the preamp is probably the third major concern. As the battery drains, its voltage drops, and voltage is what's key when powering transistors like the op-amps in your preamp. You might play with a light touch on the bass, and put that relatively weak signal through a cranked 1000w amp to get the needed volume. In that situation, the onboard preamp needs very little voltage to produce all the headroom you need, and so you can keep it in your bass longer because it does the job longer. If you dig in to the strings more, or play a lot of slapstyle, you'll notice more quickly that the beefy, bassy goodness and sharp, clear highs of a fresh 9v start to get fuzzy more quickly; it'll sound like your distorting the preamp, when what's happening is that the voltage the 9v can produce has fallen off to more like half that, cutting your headroom by about 3dB to where you can start noticing it in your fundamental bass frequencies and attacks.
  • Some preamps can take 18V of input power from two 9Vs in series; the preamp's not much different than one that can only take 9v (a little beefier in the op-amps, maybe); the extra voltage just gives you 3-6dB more headroom on a clean charge. When played the same way you would with only 9V onboard, and not really using all that extra headroom, theoretically you'll get double the total life out of the batteries before voltage drops below the acceptable threshold.
  • Other preamps are designed to take an external power source. Remember I said the preamp circuit is switched on and off using a contact in the 1/4" jack? Well, in some designs, that behavior can be "hacked" by using a TRS plug, with the "ring" contact on the plug supplying 9VDC from a wall wart (the sleeve being both a signal ground and the ground side of the power supply circuit). With your power coming into the bass via the signal cable, you can jumper the battery terminals and play indefinitely.

Whatever the type of active circuitry you end up with, if the bass takes a battery, make sure that battery is easy to change. You WILL at some point have to change one between sets or even between songs. A few models of bass, including conversions of vintage designs, put the battery inside the control cavity, requiring a screwdriver and a considerable amount of time and frustration to get to it. Most basses, however, have a battery box on the back of the body, though in a few situations it can still be difficult to remove the battery from its snap contacts. If you can get a bass with a battery box that uses pressure contacts, where you just pop the battery into the box frame and close the cover, that's typically easiest; those can be swapped in seconds if need be.
 
Re: Active PUs

Re: Active PUs

Introduce yo'self, why don't ya?
 
Last edited:
Back
Top