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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
duramax747
194 posts
 
According to the man who designed it it's pure class A as is all the XA series amps. 

https://www.passlabs.com/products/xa60.8/
dfairc777a OP
60 posts
 
Yeah, I read that too and understand that it's pure class A, but what's this transition to AB thing?  Do all class A amps have a peak transition to AB point or is this unique to Pass?
arcticdeth's avatar
arcticdeth
1,572 posts
 
122W until leaves class A....
that is a class A amp of the highest order!

  I don’t think my brothers McCormack dna-750 monos even do any class A at all, they sound great all the time, and my Odyssey kismet amps are 10W of class A, they are very refined, and have a spectacular sound until the volume gets pretty loud, at a normal to average loud volume, the class A is great!!

 Wish I had a pair of class A amps, they are simply flawless!

 Class A is sublime!

  
dfairc777a OP
60 posts
 
Indeed they are impressive.  I'm really impressed by the entire XA line, but as far as I understand, all AB amps run at some point in class A and then transition. Yes, most transition way less than 122 Watts, but I'm still confused as how a class A amp can leave class A and still be called a class A amp (Unless that's the way they all work). 
tomcy6's avatar
tomcy6
2,594 posts
 
Technically it is a Class A/B amp but Pass sells it as a 60 watt Class A amp and it does operate in Class A up to 60 watts.  He does this in order to distinguish it from his X series amps that operate more like traditional Class A/B amps (10 -15 watts in Class A then switch over to Class B).

Most people know this about Pass amps and give him a pass on it.  Now you know it too.  If you think this is wrong, contact Pass Labs about it.  
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