Hafler 9130/Pro1200 circuit differences?

[reiver]

A question for fellow Hafler owners.

I'm modifying my Hafler 9130 amplifier, and have been comparing the schematics between it and the Pro1200. They both appear to be identical except (except for one resistor, R21) and the separate circuit that looks like the power supply to drive the front end.

I'm no expert on circuit design, can anyone suggest the difference between these two circuits, I assume the 9130 version is simply a "better" design and the Pro1200 version simplified to lower costs?

-Bryan

see attached

[reiver]

I figured it out.

The "left" side of the circuit is the thermal circuit which shuts down the amp when overheating. The new "right" side is the soft on/off circuit which came out on the 9130, but not on the Pro1200.