Troubleshooting a subwoofer amp

[bobs]

When the sub is powered up with no signal from the receiver, the cone bottoms out and just remains there until the sub amp is powered down.
I think I caught it in time and no driver damage occured. I have to pull the woofer and test it.
Any opinions on whether this is repairable?
TIA
Bob

[nick29498141]

> When the sub is powered up with no signal
> from the receiver, the cone bottoms out and
> just remains there until the sub amp is
> powered down.
> I think I caught it in time and no driver
> damage occured. I have to pull the woofer
> and test it.
> Any opinions on whether this is repairable?
> TIA
> Bob

If that is happening, I would say that the amp either has a broken circuit of some type, or manged to clip. When a con bottoms out like that it usually means that the amp fed the driver too much DC current. Direct Current will make the cone go to the limit of it's excursion one way. I'd check for breaks in the circuits, or call the amp maker.

NK

[romanberry]

> When the sub is powered up with no signal
> from the receiver, the cone bottoms out and
> just remains there until the sub amp is
> powered down.
> I think I caught it in time and no driver
> damage occured. I have to pull the woofer
> and test it.
> Any opinions on whether this is repairable?

Sure, it ought to be repairable. Sounds like your amp is up against one of the rails (negative rail if your woofer has normal polarity) which means something is broke somewhere. Could be as simple as a shorted (blown) output transistor passing DC or an op-amp in the signal path that gave up the ghost.