Stomp Box batteries

Jim Cohen · Post by **Jim Cohen** » 20 Apr 2000 6:57 am

I know that if you leave the plug plugged into the input of your stomp box, it runs the battery down, but is this also true even if the box is plugged into the A/C with an adapter (but still has a battery in it)? Or is the battery circuit totally bypassed and leaving the input cord plugged in won't have any effect on battery life?
Thx,
jc

Jack Stoner · Post by **Jack Stoner** » 20 Apr 2000 7:34 am

Most units bypass the battery with an external power supply plugged in. I've got a Boss DD5 that has the same battery in it for over a year. I normally use an AC adapter but plugged it in yesterday without the adapter and it still works.

John Macy · Post by **John Macy** » 20 Apr 2000 9:18 am

One interesting thing about batteries is when I was using a Tube Screamer, it always sounded best when the light was getting dim and the battery was going down. We measured it one day, and it was at about 7.5 volts, so I got a 7.5 volt power supply made for it, and it always sounded great.

Mark Amundson · Post by **Mark Amundson** » 20 Apr 2000 9:35 am

Most (not all) stomp boxes have AC adapter jacks that will either switch out the battery or diode protect the battery clip by supplying a higher dc voltage than a fully charged battery.

Regarding the tube screamer voltage thought; the magic in tube screamers is make the internal op-amp struggle with providing a clipped signal. This is traditionally done by using cheap op-amps that can not support the current drive, thus rounding off the clipping and sounding more tube-like. By dropping voltage via a near-dead battery (higher internal battery resistance) or the reduced adaptor supply voltage, you are helping the op-amp struggle more for that tube amp sound. A couple of series diodes in battery/adaptor supply will do the same thing and let you retain fresh batteries or a 9vdc adaptor. I own a TS-10 screamer and different op-amps will give differing sounds.

Bill Crook · Post by **Bill Crook** » 20 Apr 2000 9:56 am

Most of these devices have a diode in them that allows for the wallwart to overcome the voltage produced by the battery, (naturally, we loose the .6\10 volt drop across the doide.) so this allows the "charger/adpter" to supply a bit more power (voltage) to the stomp box than the battery does thus takeing the battery out of the equasion,in affect. This keeps the current drain off the battery,in effect,as memtioned, it really isn't in the circuit. Be aware tho, a wallwart will NOT charge a battery.

I haven't run across too many devices that didn't work this way.

That is why,Jack, that your unit has lasted over a year or more.

A word od caution here ...
If the device is left pluged in, you know like a BOSS fuss box, (via a guitar cord or such) and the wallwart isn't supplying power to the device, It will still drain the battery as there is no voltage avalable to overcome the battery source !!

<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Bill Crook on 20 April 2000 at 11:03 AM.]</p></FONT>