Pass Labs XA- ".5" ???

Tbooe, you can't be serious that you haven't seen the meter move on Pass amps. On your XA amp, that series the meter should never move. But on the X series, the meter moves on my 250.5 when I play above anything approaching high medium volume levels. So, I cannot believe your claim that you have listened to other Pass amps at very loud volume and never seen the meter move. What, with 100db horns?

...the meters do move. I have a pair of Infinity Kappa 9 speakers....they dip to 1 ohm. When I turn it up and want to rock the house, they certainly make the meters on my x-600's move.

The meter thing is sure weird. I have 87Db 4ohm speaker in a 25x 18 ft room and play at medium level. The x350.5 meter only moves when I play double bass or organ stuff very loud. I barely shakes a hair on loud orchestral passages. I think the meter moves only when I switch out of class A to AB and I guess 350.5 is at least 50W class A.

With the same speaker, if the Mac meter is correct, I rarely exceed 30W.

kevziek..calm down dude...no offense meant. I heard the x350.5 with Vienna Acoustics Mahler and at what I consider loud, the meter did not move. And yes, I know that the meters on the XA do not move (I do own them after all).

What speakers do you have? The Mahlers are 90db at a nominal impedance of 6ohms.

Anyway, as I said in my post, this is just my opinion and my experiences....

Kevziek is right though, the meter on the XA series is just a "nice-to-have" feature and does not perform any function.

On the X.5 series, the meter, when it starts moving, indicates that bias on the amp is going from Class A to A/B operation.

My B&W N803s make the meter move on my X250.5.
Playing a recording with some decent bass/mid-bass, I have to get the preamp volume above the 10 o'clock position and the meter on the amp starts moving.
But I love the Class A operation of the X250.5 amplifier when listening on low levels. Plenty of drive, slam and detail.