question on active/passive basses

[redname]

hi, i was just playing around with 1 of my bass and since i remember i took out the battery, i switched to passive and as usual there was sound, now what's next seems weird to me

I switched it to active mode and there's still sound, this has never happened to my basses with active/passive switch, normally if there isn't any batteries, active mode will not have any sound

so is my electornics having some issues?

 

[Raenil]

Maybe the switching lead to better connection and thus more power from the battery?

 

[Tosh]

If that happened with my Dynabass I would suspect the passive/active switch had failed. Without a battery, my preamp has no juice and therefore no sound when it's switched to active mode.

 

[kgbeast]

Some preamps schematics can output very low signal without a battery.

 

[MoireBass]

Most bass preamps use active devices called op amps*. Op amp preamps can be connected in two basic configurations, called inverting and non-inverting. The inverting configuration has a pathway from the input to the output and will pass a weak signal if power is turned off or even if the op amp is removed. But it won't amplify the signal without power. The non-inverting configuration does not have a similar pathway and won't pass any audio without power.


* op amp is short for operational amplifier.

 

[hrodbert696]

Not really an answer to the OP, but just a comment - I don't have any active basses. I DO have a Godin Session electric guitar, which has an active circuit that's engaged with a small button on the control panel, next to the tone knob. I don't really have any use for it (actually I don't play much electric anyway), so for fun I just took out the battery. Now that little button acts as a stutter switch, which can be fun to play around with.

 

[redname]

Maybe the switching lead to better connection and thus more power from the battery?

Not really sure what you meant but there wasn't any batteries inside

 

[redname]

Some preamps schematics can output very low signal without a battery.

It was loud enough actually, thts y was surprised

If that happened with my Dynabass I would suspect the passive/active switch had failed. Without a battery, my preamp has no juice and therefore no sound when it's switched to active mode.

Exactly the same thing

 

[redname]

Most bass preamps use active devices called op amps*. Op amp preamps can be connected in two basic configurations, called inverting and non-inverting. The inverting configuration has a pathway from the input to the output and will pass a weak signal if power is turned off or even if the op amp is removed. But it won't amplify the signal without power. The non-inverting configuration does not have a similar pathway and won't pass any audio without power.


* op amp is short for operational amplifier.

But even if it passes signal, it's very low right?

Mine isn't, it's loud enough to sound almost like passive