Tuesday, July 9, 2024

How long can you leave an amp on?

 How long can you leave an amp on?

As long as it isn’t a badly designed piece of s@@t, 24/7/365.

I have repaired stereos, PA amps, music reinforcement and musical instrument amplifiers for decades. Part of my testing involved running them at 20%, 50%, 70%, and 100% power and with music for 24 hours at a time. I’d test them for longer, but time is money and I only have four 1kW speaker dummy loads, and this will catch 99.9% of any after-repair issues.

For a class AB push-pull amplifier, about 70% power with a sine wave or bass-heavy music with just a tiny bit of clipping is about as hot as it will get.

As long as you don’t block the airflow (don’t drape things over an amp) or spill things in it, a well-designed amp will not get so hot it fails due to the heat. Keep the vents clear, dust external heat sink fins.

That said, heat is the enemy of electronics. Elevated temperatures shorten the life of electrolytic capacitors and semiconductors.

Modern Class D power amplifiers can be pretty wonderful. Short circuit protected, very little heat generation.

Keep the electrolytic capacitors away from heat producing components, don’t block the air vents or put the amp in a closed or semi-closed space. An inch above an amp with vents is NOT enough space for passive convection cooling, you may need to add a small, quiet fan to move air a bit if you can’t give it more space.

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