Pass Labs XA-25 vs XA-30.8 amplifier

I had the same question for other speakers and there was a lot who really think the XA-25 is a very special amp. I love mine and you should read about it. The only question I have for your speakers is what the impedance curve looks like; if it needs power, then perhaps you need a more powerful amp than either of these. But the XA25 can deliver a lot of juice and it has driven every speaker I've tried with it, including some around the (basic) specs of your Audiovector.

Pass Labs XA-25 - Was more controlled with driving the speakers that were demoed 

The Pass Labs XA-30.8 on the other hand could sometimes feel more loose but note I heard this at a different place but with the same speaker.

Sled noise on idle was better on the XA-25 that's for sure and is more efficient but maybe it's me but the actual sound didn't differ in any meaningful way @klarinet 

From amp designers I know, the XA25 has some of the finesse and sweetness of the First Watt line Pass makes, but no other Pass amp does this (except in the SIT series).

Here’s something relevant:

"Based on actual comparisons, it’s thus fair to say that the XA25 packs virtual Nagra-type small-bottle sonics in the areas of tonal bloom and the ability to track recorded decays. If now we return to Nelson Pass’s 2017 design notes, these results would seem less due to the ‘single-ended’ use of his unusually potent Ixys output devices but what their use eliminated – typical degenerative feedback. It’s how the XA25 differs from our XA-30.8; and apparently how it manages to eclipse it on subjective speed and suchness without sacrificing the usual markers of class A Pass tuning. We’re told that scaling up this recipe to power ratings well beyond the XA25 won’t be easy. In fact, I don’t think it’s happened yet. In that regard, buyers pursuing the smallest amp in the current Pass Labs catalogue actually get something the bigger ones don’t have. It’s bragging rights of a different sort. Here it’s not the guy with the heaviest costliest amp who wins but she who bought smarter speakers which don’t require excess power so can exploit a smaller more sophisticated or purist gain circuit to drive them. In case you’re still reading between the lines: had I discovered the XA25 before I purchased the XA-30.8 as my resident class A example, I’d have saved myself both money and handling fits. I like the sound of the smaller amp even better; and my back much prefers it, too."

https://darko.audio/2023/02/pass-labs-xa25-review/

Also: https://www.stereophile.com/content/pass-laboratories-xa25-power-amplifier-page-2

I’ll start by saying I am not familiar with your speakers and I never heard XA-25. 
I owned XA-30.8 and upgraded to X260.8 mono amps. 
I used XA-30.8 with Martin Logan Montis and Wilson Sabrina speakers. Preamps were XP-12 and XP-22. 
I can characterize the XA-30.8 sound as warm, big, luscious, with rounded edges, big but wooly and somewhat loose bass. I found that Pass Labs XA30.8 and even X260.8 but to a lesser degree than the 30 tend to homogenize the recordings you’re listening to. There’s an upside to this as it will make pretty much everything sound great and let you enjoy the music. But it’s not the last word in transparency. The XA30.8 is a great amp overall that packs enough juice to scale up to some demanding speakers. I can highly recommend it if the sound I described is what you’re looking for. 
If you want Class A but faster and more transparent sound I highly recommend Coda. Great amplifier and I ended up preferring a Coda CSIB integrated amp overall. The CSIB is basically Coda 8 with built in preamp. Look into it. 

It seems like the XA-25 is generally regarded as “transparent”. Maybe the big selling point for the  XA-30.8 is the balanced inputs? One thing that makes me hesitant about the Pass amps is the 3 year warranty, 5 years is pretty standard. Has anyone had reliability problems with their Pass amps?

Pass stuff is super reliable. They also have exemplary customer service.
I wouldn’t worry about warranty. 

Super reliable, and great customer service - have had 5 Pass amps over past 21 years

The Pass class A amps are not pure class A. They are class A up to the rated power but then they go into AB for a lot more power. The XA-25 will put out a clean 75 watts easily. But except for super short peaks the amp will stay well below its class A power. So it's sort of 99% class A with AB emergency power.

@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.

Oh and I normally don’t listen at loud levels, but want to have something in the tank for when the Tympani’s bang out their part.😁

Thanks again.

@curiousjim I bet they'd be fine for those speakers. A lot depends on the impedance curve but I used the Pass XA25 for speakers with very reasonable impedance curves at 87 and 91 db sensitivity and the amp never faltered. 

https://www.audioholics.com/loudspeaker-design/loudspeaker-sensitivity

Basically (in case you don't know): 

An audio speaker's impedance curve shows its electrical resistance across frequencies, indicating how easily an amplifier can drive it. Curve dips to low ohmic values (e.g., 2-4 ohms) demand more current from the amplifier, making it a harder load. A large phase angle (deviation from 0 degrees) at certain frequencies further stresses the amplifier by forcing it to deliver voltage and current out of sync. Speakers with significant dips and phase shifts are tougher loads, requiring more robust amplifiers.

The XA25 is designed to deliver significant current, with a peak current output of 10 amps, which translates to a 200-watt peak into a 2-ohm load. It also has, if I recall correctly, a damping factor of 500 and this gives it excellent control over the speaker's drivers, especially the bass passages.

You may want to add the coda no 8 amplifier to your list.

the coda no 8n is way more flexible the no8 can be ordered in three different variants

V3: 400 Watts x 2 into 8 Ohms

800 Watts x 2 into 4 Ohms

Class A ~8 Watts

V2: 250 Watts x 2 into 8 Ohms

500 Watts x 2 into 4 Ohms

Class A ~12 Watts

V1: 150 Watts x 2 into 8 Ohms

300 Watts x 2 into 4 Ohms

Class A ~18 Watts

"The $6,800 Coda No. 8 is very musical yet very detailed in ways that make me think that a fairer comparison would be my $13,5000 Pass Labs XA-60.8 monoblocks, which is a significant accolade for the Coda No. 8, as the Pass 60.8s are mean competitors costing far more money." - Terry London, Home Theater Review

At any time you can re-bias the amp at the factory so you can increase the amplifiers output 

Dave and Troy

audio intellect NJ

coda dealer

@curiousjim 

Nice speakers. I have Amati Traditional and power them with ARC Ref 160s in triode mode... so 70 wpc instead of the 140wpc in linear mode. They are not compromised in any way... but this is a tube amp. 

While you could probably "get away" with the small Pass. I would look up the Pass XA line up to better match with higher power. 

I purchased efficient speakers so I had flexibility with my amp purchase.

I have the XA25 running through a Khozmo preamp into the Crites speakers, which are Klipsch clones.  The amp is very pleasant and neutral.  Very good bass. Build quality superb. I will not be selling it. The 30.8 will be warmer but a even beefier amp, it puts out over 100 Class AB. It also weighs 90 pounds which influenced my decision.  If some talks you out of Pass there is Ayre, Luxman, Sugden and Coda which all have generous Class A output.