PASS - comparison X 350 to XA 60.5

My comments are based on a conversation with Pass Labs two years ago. I had called to ask about the changes on the rear panel between earlier and later versions of the X250.5 The RCA and XLR connectors are located differently on later models.

I also noticed that the location of the speaker connectors and fuses had changed, and they used a different rear power switch.

These changes without changing model number are not really that uncommon. I had an ARC LS15 preamp and noticed that a friends LS15 had a detachable power cord and different capacitors. I called ARC who confirmed this, and was able to have them upgrade mine. I have also owned two major audiophile brand speakers where the designer/owner confirmed changes made without changing model number and offered upgrades.

Pass Labs did indeed make a change, adding the "signal ground pin".
I believe it's on all later X.5 & XA.5 amps.
I think this is for grounding subs like the RELs.
Ask your local Pass dealer, or just contact Mark at Reno HiFi.
He'll answer any question on Pass.