Power-down thumps from TE AH250SMX

[ttyR2]

The wife's RAH250SMX is in a rack running off a power strip. If we turn the system off using the power strip, a few seconds later we get thumps coming out of the speaker that trail off after five or six seconds. A different power strip does the same thing. It doesn't happen when using the onboard power switch on the amp, but we do hear it if that switch is off and then turn the power strip off (which is very odd). Any ideas?

[Dekker]

Yes, an old thread, but I found it while searching for something else. But if you are still around ttyR2, it is because when you us the power switch on the amp, the amp disconnects the internal power from the outputs, and therefore the power capacitors in the amp discharge without making any noise.

When you use a separate power switch to cut power to an amp, the power supply stops, but the energy stored in the capacitors of the amp still has a path to the speakers. As they slowly drain, they reach a point where they just "drain" suddenly, causing the "thump" you hear.

To avoid such thumps, you'll have to power off the amps directly. Note, many digital amps (class D) should not exhibit this effect...

Dekker

[DD_BigBottom]

Originally Posted by Dekker

Yes, an old thread, but I found it while searching for something else. But if you are still around ttyR2, it is because when you us the power switch on the amp, the amp disconnects the internal power from the outputs, and therefore the power capacitors in the amp discharge without making any noise.

When you use a separate power switch to cut power to an amp, the power supply stops, but the energy stored in the capacitors of the amp still has a path to the speakers. As they slowly drain, they reach a point where they just "drain" suddenly, causing the "thump" you hear.

To avoid such thumps, you'll have to power off the amps directly. Note, many digital amps (class D) should not exhibit this effect...

Dekker

Just like to add that your should directly power OFF the amp FIRST. You will get thumps and pops from the gear in front shutting down if you power those down while the amp is still on.