Pass 250.5 shuts down driving Magnepan 3.7


This is my first post so please bear with me.

My Pass labs 250.5 protection circuit shuts the amp down when I drive my new Magnepan 3.7s at high volume. I'm talking about a volme higher than I might consistently listen, but not an unbearable level.

I'm using a Cary Slp 05 preamp with long balanced ICs (25 ft,) The amp is close to the speakers with less than 6 feet of speaker wire. The system works fine at normal volumes. I've tried the same thing with a pair of Cary MB500 (750 W @ 4 ohm) and they too shut down at high volume.

I believe the maggies drop below 4 ohms and I wonder if either amp can handle the impedance drop below 4 ohms.

Has anyone experienced this issue ?

Any suggestions ?
gcoxsom
Suggestion: do not play your system that loud.
Otherwise, toss the amps and buy Bryston.
I had a problem at high volume using tube ARC monos.

I think the amp is seeing something it doesn't like impedance wise.

Are the bass panels rattling at these volumes? Are you playing very dynamic music? Things with sudden big bass hits?
I suspect there is a problem with the speakers. My Cary 500 MB's have never shut down driving my 3.7's. Do both channels of the Cary shut down?