GAS Ampzilla only both channels with Headphone plugged in

[Markie]

This morning, all of a sudden only the left speaker was working on my sound system, powered by GAS Ampzilla II, on Megnepan Speakers.

Also, only the left DB meter is showing output, the right indicator remains on Zero.

I decided to plug in my headphone into the Ampzilla, to see if the issue is speaker related, and as soon as I did, both Magnepan speakers came back on. Not just on the headphone... now both speakers are working fine, and both DB meters indicating normal.

HEADPHONE PLUGGED IN = AMPZILLA WORKS AND INDICATES NORMAL, BOTH MAGNEPAN SPEAKERS WORKING
HEADPHONE UNPLUGGED = AMPZILLA ONLY INDICATING ON LEFT CHANNEL, ONLY LEFT MAGNEPAN SPEAKER ON

Any thoughts?

[scorpio333]

The left channel only works when the headphones are in?

I'd start by cleaning that headphone jack.

[Sir Thrift-a-Lot]

The left channel only works when the headphones are in?

I'd start by cleaning that headphone jack.

That was my first thought as well but it seemed obvious.

[Markie]

Thanks for the thoughts. I found out something else:
When the headphone is plugged in, both magnapan speakers are working as mono (off the left channel). Meaning the balance lever at the pre-amplifier is working as a volume lever.

The headphone somehow "hot-wires" the left channel to the right channel.

Again, I am not concerned about the output on the headphone it self, the issue is the main speakers (or main amplifier channels)

Only the left Maine speaker works (and left channel on amplifier), that is the issue I would like to solve.