Why is my (Acurus) amp doing this?

[EJD]

I have an Acurus A250 in my 2ch system. These amps are known for being able to continue playing for about 45 seconds if you turn the amp off before the source (I think it has something to do with the capacitors storing current in reserve and taking time to fully discharge). It's not a flaw, just the way the amps were designed. I have always known this and usually just shut off the CD player first.

However, tonight I noticed that after I shut down the amp, there is a faint, but audible sound coming from the amp through the speakers about 45 seconds after turn off. It's a fairly high pitched sound coming from the tweeter that lasts about 15 seconds until it just fades away. I'm no electrical engineer, but it sounds like the current draining out of the caps (similar to a bottle rocket fading into the distance).

It is possible that it has done this all along, but I usually walk out of the room after I shut it down - and it's fairly quiet, so maybe I just never heard it before. However, I don't think it usually makes this noise.

Does anyone have any insights as to whether the noise is indicative of a problem - either a present or future one? Does this happen to anyone else who currently owns an Acurus amp? Would you be willing to test yours and check it out?

Thanks

 

[surveyor]

I get the same sounds when I power down my system. I have my two main speakers passive bi-amped. My thoughts are that the sound you hear with your system is fine. It won't hurt a thing.

I have an Acurus A250 in my 2ch system. These amps are known for being able to continue playing for about 45 seconds if you turn the amp off before the source (I think it has something to do with the capacitors storing current in reserve and taking time to fully discharge). It's not a flaw, just the way the amps were designed. I have always known this and usually just shut off the CD player first.

However, tonight I noticed that after I shut down the amp, there is a faint, but audible sound coming from the amp through the speakers about 45 seconds after turn off. It's a fairly high pitched sound coming from the tweeter that lasts about 15 seconds until it just fades away. I'm no electrical engineer, but it sounds like the current draining out of the caps (similar to a bottle rocket fading into the distance).

It is possible that it has done this all along, but I usually walk out of the room after I shut it down - and it's fairly quiet, so maybe I just never heard it before. However, I don't think it usually makes this noise.

Does anyone have any insights as to whether the noise is indicative of a problem - either a present or future one? Does this happen to anyone else who currently owns an Acurus amp? Would you be willing to test yours and check it out?

Thanks

 

[Seth=L]

Older amplifiers without relays will usually bleed off the capacitors. My Hafler will play about 4 seconds solid at a moderate level of output to empty the caps. If I power it off with no source it bleeds off very slowly, not audible. Other amplifiers will hold the charge for a time, then suddenly release a large sum of capacitor's energy generating a loud thud, my M&K subwoofer would do this when powered off. Other amplifiers will use an LED to consume the remainder of energy stored.

All that said, it is normal for the amplifier to empty the capacitors and shouldn't be harmful.

 

[fmw]

Capacitors age more and faster than other electronic components in the circuit, particularly the electrolytics. Possibly you are hearing one aging a little if you didn't hear it before. It is nowhere near a matter of concern.