Bass Player Readers' Choice Award for Best Preamp: Audere JZ3              Bass Player Editors' Award
Introducing Jazz Hum and Noise Cancelling Preamps - keep the Single Coil Tone and Touch Response - lose the Hum and Noise              BP Magazine Review
Zmode switch

Module size approximates battery size

FAQ - Battery Power...

How long will the battery last?
Should I unplug the instrument when not in use?
Battery Width vs Jazz Cavity Width?
Can I use a rechargeable battery?
What if I use cheap batteries?
What if I use heavy duty batteries?
Why would I use 18 volts instead of 9 volts?
Do I need a power on/off switch?

How long will the battery last?
A single 9 volt battery should provide 200 hours of playing time in a 3ZB and a little over 250 hours in a JZ3 preamp. This assumes normal room temperature, quality alkaline batteries and constant operation. In reality batteries have some recovery capability when not used so the life should increase beyond that when you play the bass for several hours a day. If you use an 18 volt system the life will be significantly longer, > 1000 hours.
Should I unplug the instrument when not in use?
Unplugging in-between sets or songs, for example, would not be recommended but we definitely recommend unplugging the instrument at night or if it will not be used for a long period.
Battery Width vs Jazz Cavity Width?
Some Jazz cavities are just over 1" in width. These slightly narrow cavities can create a problem with some brands of batteries. Most types of batteries are getting wider and thicker as users want the longest battery life. But when the battery will not fit into your jazz cavity or the battery box the effective life is zero.
Energizer Alkaline batteries are very consistent in size at 0.999 inches wide.
Can I use a rechargeable battery?
Yes but this is not a good application for a rechargeable battery given the unit's low power pull. All batteries discharge when not in use and this self discharge rate is significantly higher for a rechargeable. As rechargeable battery technology improves this tradeoff may change.
What if I use cheap batteries?
This is probably not the ideal place to use cheap batteries because they typically have a much higher self discharge rate. Since our preamp does not pull much power, the cheap battery, like most rechargeable's, will drain itself faster than we do. Buying a premium battery may actual cost you less cents per hour of usage.
What if I use heavy duty batteries?
Depends on what kind of 'Heavy Duty' battery it is. If heavy duty means you are getting a 'Premium' battery (as is typical in the case of the 9 volt size), this is a good idea.

A true 'Heavy Duty' battery is designed to deliver a higher current flow for circuits that need high power for a short time. A common example is a battery that says it is for a camera flash - it enables the flash to recycle faster so you can take the next picture sooner. But, these heavy duty batteries cost more and typically have less chemistry in them; in order to increase the contact area they reduce the space allocated to the chemical solution. This would be an ineffective tradeoff for this application.
Why would I use 18 volts instead of 9 volts?
With an 18 volt system you will get more head room. This might be important if you like to run in Low-Z mode and max the bass control or have very hot pickups. However, many of the external bass amplifiers will clip long before the preamp will at 9 volts. An 18 volt system will also provide for longer battery life. In general, this is a very nice preamp implementation which works well at both voltages and running it at 18V will not add noise nor will it shorten the battery life like some of the other on-board preamps.
Do I need a power on/off switch?
No - most (almost all) bass preamps use a stereo jack connected as a switch so that when a mono guitar cable is plugged into the instrument the low side of each battery is connected to ground. If you want to add a power on/off switch it is easy to do.