Takamine preamp, how to test if its draining my battery?

[drakoryn]

Hi I have a Takamine p3dc with the Ct4b2 preamp. I suspect the preamp might be draining battery even when a cable is not plugged in as the battery only lasts around 20-30 hours (as opposed to 100+ as per other user experience).

Is there any way I can troubleshoot this to know for sure if the preamp is draining battery even when unplugged?

Thanks for any advice!

[cmac]

As per the Takamine website (https://www.takamine.com/pre-amps#ct4b) "When the guitar is unplugged, the TUNER POWER switch acts as on and off."

Is it possible you have been leaving the tuner switched on?

[drakoryn]

I have forgotten to turn off the tuner before and that certainly dropped the battery life. But I have tested before and made sure I didn't forget to turn off the tuner. Still only got about 20-30 hours of battery life

[cmac]

Well, to answer your question, you would want to put an ammeter (e.g. a digital multimeter) in series with the battery, i.e. one probe goes on a battery terminal and the other probe goes on the connector that would normally go onto that battery terminal. Then set it to show current and see what happens.



But I assume the preamp is like my old Tak preamp, and it doesn't have a pull-out wire connector for the battery - instead, I assume it has a couple of springy metal tabs at the bottom of the battery compartment.

So the choices are to take the preamp out completely and open it up to get access to the battery wiring, or to put together some kind of battery-shaped thing that goes into the preamp's battery box and basically extends the compartment's terminals out to a more accessible place.

For example, you could take a battery (ideally a drained one) and tape over the terminals so that it's just acting as a convenient battery-sized lump. Then tape two pieces of wire onto it such that there is bare wire exposed right where the battery terminals are (but secured so that those bare wires will never accidentally touch).

Put that in the preamp, assuming the wires aren't too thick to prevent it, and now you have wires in contact with the preamp's battery connectors. Now put one wire on a battery (the appropriate + or - of course) and the other on the meter probe. Now put the remaining meter probe on the other battery terminal and you should be able to turn on the tuner / plug in a cable and verify that the circuit is made while also observing the current draw on the meter.

Then all that's left is to turn it off and check if the current draw drop to zero or not.

[drakoryn]

Hi Cmac, thanks for the detailed explanation. Exactly what I was looking for!