Power Surge (Any damage)

[NicolasGaal]

Hi, I pulled the power cord to my amplifier out when it was on. There was no music or movie or any sound going through the speakers at the time as the DVD player was off. However when the cord was pulled out a loud distorted sound came from the speakers. What damage does this kind of thing normally do or can to speakers or amps.

[sek]

Does it never happen when You use the amp's power switch. I.e. did it never happen before?

Sounds like your amp was having a problem at that very moment, I can't tell you if that's it's normal operation, tough.

As your intuition tells you, this thing can do harm (at least) to speakers. It's usually called "power on noise" or "hump" and is an effect of the amp not being powered sufficiently. In such a "brown-out" condition an amp can build up oscillation, DC and/or noise at the output. People all over the world frequently damage their speakers this way.

As you seem to have recognized it for the first time, you should check your amp for problems. Any measurement equipment at hand, or at least a cheap (small) speaker you can waste (e.g. the beep-type built in computer cases)?

Hope this helps,
Sebastian,

edit:

Another thought: if the amp was drawing an (idle) current while you pulled out (which it presumably did), the wall plug loosing contact to the outlet could just have made the noise itself. Splitting contacts while they conduct current always emitts electromagnetic waves, either through the amp's mains inlet and via radiation (through the air ). Remember flashing light switches while switching?

Just take the cheap speaker you just thought of and connect it to the amp. If that noise sometimes occurs when quickly pulling the cord out (make multiple tries, pull on the plug, not on the cable, and hold the wall outlet with your other hand!) but never occurs when using the amp's main switch, well, then everything's fine.

[NicolasGaal]

The amplifier was on and I pulled the cord out and then the noise came. If I just turn the amp of at the button there is never any noise. I am just worried if I have damaged my speakers in any way. How can i find out if they are damaged at all.

[gary f]

Just listen to your system to hear if there is any damage. I doubt that this will do any harm to your speakers.

I have an amp that makes a big "thump" noise each time I turn it on. The woofers get full excursion out like when plugging DC. Well, although this is surely NOT recommended for any system, it did never damage my speakers in any way. The tweeter is protected by the filter from DC input. It is possible to damage the woofers but these things are strong generally.
F

[sek]

it did never damage my speakers in any way. The tweeter is protected by the filter from DC input.

Lucky you! Although the tweeter is kept "dc-free", it all depends on the power of that surge, not only the dc level...

[Bull]

My amp has a strange switch on delay to stop thumps which makes a loud 1 second hum + thump in the amp[probably inrush current to transformer].But it seems to be protected against spike/surge,cos once the breaker tripped[faulty appliance in next room],no thump in speaker,but a thump came from the amp instead,but no damage.
So the power supply in this power amp [Parasound] must have some special filter circuit to bypass the spike/surge through the transformer instead.