The XA60.5 amps may work with your Theos. The amps deliver 60 watts of Class A power at into an 8 ohm speaker, then they switch over to Class A/B mode and can deliver about 130 watts into 8 ohms.
Here are the measurements that Stereophile got from the XA60.5s:
"The needle of the front-panel meter remained just to the left of 12:00 at 8-ohm powers below 60W. At 60W it moved slightly to the right, reaching 1:00 at 100W into 8 ohms and 1:30 at 120W. Specified as putting out 60W into 8 ohms (17.8dBW), the XA60.5 considerably exceeded that power, delivering, at 1% THD, 130W into 8 ohms (21.1dBW, fig.4), 210W into 4 ohms (20.2dBW, fig.5), and 330W into 2 ohms (19.2dBW, fig.6). The THD starts to rise above the noise floor at high powers, but is very low at powers of a few watts with a 1kHz signal, even into 2 ohms."
I would talk to the people at Pass or Martin Logan to see if that is enough power for your Theos.
Here are the measurements that Stereophile got from the XA60.5s:
"The needle of the front-panel meter remained just to the left of 12:00 at 8-ohm powers below 60W. At 60W it moved slightly to the right, reaching 1:00 at 100W into 8 ohms and 1:30 at 120W. Specified as putting out 60W into 8 ohms (17.8dBW), the XA60.5 considerably exceeded that power, delivering, at 1% THD, 130W into 8 ohms (21.1dBW, fig.4), 210W into 4 ohms (20.2dBW, fig.5), and 330W into 2 ohms (19.2dBW, fig.6). The THD starts to rise above the noise floor at high powers, but is very low at powers of a few watts with a 1kHz signal, even into 2 ohms."
I would talk to the people at Pass or Martin Logan to see if that is enough power for your Theos.