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Pass Labs Xa60.8 Class A or should it be called class A/B?

I'm looking at possibly purchasing the Pass Labs Xa60.8, but am puzzled by one of its specifications.  One reviewer stated that "The XA60.8 doesn’t leave pure Class A until it reaches 122 peak watts. Then it moves into Class AB for unheard of headroom for a 60-watt amp".  I've confirmed this headroom is on the specification sheet, but if the amp actually can transition into A/B, shouldn't it really be called class A/B?  Also, I'm confused as to if this headroom is available as continuous watts or just peak.  Can anyone clarify?
dfairc777a
charles1dad's avatar
charles1dad
10,250 posts
 
From JA/Stereophile, 
"Specified as putting out 60W into 8 ohms and 120W into 4 ohms (both 17.8dBW), the XA60.8 considerably exceeded that power, delivering, at 1% total harmonic distortion (THD), 150W into 8 ohms (21.8dBW, fig.4), 240W into 4 ohms (20.8dBW, fig.5), and 380W into 2 ohms (19.8dBW, fig.6). The THD begins to rise above the noise floor at high powers, but remains at or below 0.1% below the specified output power. The percentage of THD then slowly rises with increasing power, suggesting that the XA60.8 has only a small amount of corrective feedback."
Charles 
dfairc777a OP
60 posts
 
I’m assuming that all the output above 122 watts (at least for 8 Ohms) is class B. Makes sense and shows tons of headroom. I can’t wait to get a set of these.
infection's avatar
infection
808 posts
 
Contact Desmond at Pass. He is extremely helpful. 
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