Damage amplifier by not connecting a speaker?


2010-08-15 2:09 pm
I've heard not having a load on a tube amp is bad news, but can a car amplifier be damaged if you have it powered up and playing on some channels and no speakers hooked up on other channels?

I ask since my boy installed an infinity 5 channel amplifier in his pickup. He was planning on hooking up his dash speakers to the front channels, but wanted me to hear how the door speakers and sub sounded. Well, the amplifier played for around 5 minutes and went in to protect mode. The amp never would reset (even the next day) so we sent it back to infinity for a replacement. BTW - It was a brand new amplifier.

This led me to wonder if the lack of a speaker load on the front channels caused this failure, or if it was just a coincidence.

Thanks for your thoughts.


2010-08-15 2:09 pm
Yes. It stayed in protect mode even with all the loads removed. I figure there was just something "shaky" about the amp right out of the box, but figured I would ask.

The manual says this about the protect light:
Protect LED
• Illuminated under any of the following fault
conditions: battery over/under voltage, short
circuit in speaker wires, amplifier is too hot,
amplifier’s output circuit has failed (DC voltage
present in the amplifier’s output).

I had checked the input voltage, temperature was cool, no speaker shorts, but found a pulsing dc voltage on the speaker terminals for the channels that hadn't had a speaker hooked up to them while it was playing. That is the main reason I was curious about the no load situation.