Pass Labs XA-25 vs XA-30.8 amplifier

@OP. From personal experience, Passlabs products are extremely reliable.

As Dynamiclinearity says above, the number in the amps' name is the Class A power output.

Hi-Fi News magazine has just reviewed the 30.8. The concluding line is "It's a performance that should put a smile on the face of all audiophiles, bar those obsessed with 'clinical neutrality', and for a sane price."

Paul Miller measured the following dynamic power outputs into 8, 4, 2, and 1 amp loads: 105w, 205w, 357w, and 470w. That's on a 230V mains. Pass power amps sound a lot more powerful than they rate nominally, because they are a lot more powerful.

Dynamic power measurements aside, I've never heard any change in character in my 60.8s when driven hard, albeit in a small room where I don't need massive volume levels and I doubt the amps ever stray outside of their Class A power output.

I cannot comment on the 30.8 but the XA25 is a superb amp, utterly transparent, that will drive my Rockport Atria IIs easily.  It is revealing of poor recordings however.  You hear EVERYTHING that is on the source, a singer's breathing, a a guitarist's fingers on strings and decays that last forever.  On a piano you are aware of the shape of each note.

It is rated at 50 watts into 4 ohms at .1% THD, class A.

My setup is Aurender, Esoteric K-01XD, Benchmark LA4, VPI Scoutmaster with Koetsu RSP.  Cardas cables.

I flip back and forth between the XA25 and a premium Elekit 8600S and love the sound of both, the revealing, detailed (but still musical) precision of the XA25 and the more organic, concert hall like, presentation of the SET.

Unfortunately I cannot compare the XA25 to the XA 30.8 as I own the XA25 and never heard the 30.8. 
As others have mentioned, the XA25 is a “different” Pass amp and not just in that the 30.8 has balanced inputs and the XA25 does not. From everything I have read (and is represented in the quoted article above), the XA25 is designed differently with different design goals in mind. I am not an EE, but I did try reading through the quite long diyaudio thread about the XA25 and it clearly kept many folks guessing on the design - even with Nelson’s occasional and sometimes humorous prodding.

 I will also say that it is not your average 25 watt amp. I use it with my Dynaudio Heritage Specials, which are not that efficient, and in my space and at the levels I listen at - definitely not arena rock, but occasionally a bit louder than moderate - I have never felt that the XA25 was underpowered. Just my opinion of course and I know some others have felt that the HS speakers did respond better with more watts, but I am incredibly impressed with the XA25 and HS combo.

As for reliability, Pass products are built incredibly well and with reliability as a first feature. 

Additional comments about my Pass XA-25:

The bass is not woolly or fuzzy. Across speakers from 87db to 97 db sensitivity.

The amp is not clinical.

The amp sounds different with a tube preamp vs. a solid state preamp in front of it, but it never lacks the musical warmth that @audphile mentions. With his 30.8.

The amp's name belies it's power. It has a lot of "grunt" / horsepower.

Hey all,

 I have a pair of Sonus Farber that are rated @91dbs.  SF say they need 50-450 watts.  How do you think the XA-25 would do with the Amati G5’s.