Pass XA25 for my system

@jayctoy brings up a good point about Plinius, and this SA103 is a really nice Class A amp at a very good price, and it’s got plenty of power for your Dynes.  Plus it has a low-bias switch so you can leave it on and warmed up without killing your electric bill.  Just another option. 

Plinius sa100 is almost as good as the XA 25 . The Plinius has more power it sounds like tubes too

@bluethinker I've wondered about that Audionet amp you've got now! Can you share more about your impressions of it? 

I had thought that I tried all combinations between my existing Pass/Coda and the new Audionet gear, but I realized that I may not have tried the Pass XP-12 in front of the Audionet AMP. The point is that I cannot completely separate my impressions of the AMP from those of the Pre G2, together they are fantastic. When I received the gear, I only introduced the Pre G2 into my system at first, in front of the Coda. I was so taken with that I never went back to the Pass. But then inserting the AMP in the system took things to a whole new level. 

My speakers are KEF Reference 1's and I had them fairly close together for a variety of reasons. After listening to the Audionet gear for awhile it became clear I was not hearing everything and I pushed them out to about eight feet apart, leaving just a foot of space from the side walls. The soundstage is out of this world, with clear placement and presentation of everything in the recording. You might say I am just listening to my gear, and not the music, and there is some truth there, however as noted previously, the overall presentation is natural, clear and detailed, but not overdone in any way. I am using a Merason Reuss DAC, which helps with the natural part.

I like my bass, but I am a low volume listener. My ears are overworked from many years of going to shows and listening louder than I should. The majority of my listening is now acoustic jazz, and my system is built to deliver  full sound at low volumes. The bass with the Pre G2 in front of the Coda is very good. The bass with the Pre G2 in front of the AMP1 is a whole other thing. So well defined, but not unrealistically tight, with excellent bloom and decay. If you look at the specs of the AMP1, the damping factor is listed as: > 10,000 @ 100 Hz. That is a pretty extreme number, but it sort of feels like it when you listen. It's nice.

The AMP is single ended only connections, so I am in search of the ultimate RCA cable now and my fancy XLR's sit on the shelf. And it does run a bit warmer than the Coda, but this time of year at the 45th parallel, that is okay.

I hope that helps.

@sfpeloton Thanks for your kind words on my system - l certainly enjoy it!

Just wanted to clarify when I mentioned the warmth of the XA25 and perhaps I chose the incorrect word. I find that the XA25 has an exceptional naturalness of timbre for a solid state amp. IMO, some solid state amps excel at dynamics, bass control, “oomph”. While the XA25 is certainly not the final word in solid state muscle, it certainly does have some of it, but is not at all sterile, which in my listening some solid state amps are, even with those other qualities. The XA25 is very balanced sounding, smooth, and organic, which are characteristics that appeal to my ear.

Of course ears, rooms, and so many other things vary. I just wanted to provide a bit more clarity on my use of the word “warm”.

I noticed the input impedance is 37 kohms. I think the LTA is 50 ohms so it should be okay? Any concerns about impedance mismatching or the pairing with the LTA?

No, you’re fine.  You want the input impedance of the amp to be at least 10x the output impedance of the preamp, and you’re well over that. 

I have the XA25 paired with Harbeth 30.2, 6 ohms 86 db. My room size is 20x12. It is plenty of power and I like to listen to high volume. Class A at high volume is a big plus compared to AB. The XA25 is one of the most transparent amps. It is being used by many reviewers as a reference amp.

You have a great set up and the XA25 is definitely worth a listen. It is keeper for me. I am using Cardas Clear rev1 as the interconnect and a Luna Mauve speaker cables. The sound is very organic and natural. Cable matching based on sound preferences is also an important consideration.

If you think the Xa 25 is warm, take a look at your wires.

@cbrez - I ended up purchasing a used Gryphon 120 which does 240 watts into 4 ohms. It was at that moment that I realized the full potential of the Dynaudio Heritage Special speakers. They are fantastic speakers and I just feel they really open up when driven with more power.

My former 87db 4ohm Totem Acoustic speakers with the original Dynaudio drivers were very similar in how they responded to the right type of power amplification.

I had tried several different lower power SS and Tube amps with them. Eventually arrived at 200wpc 8ohm / 320wpc 4ohm with a dual mono dual torroidal transformers - A true 75 amp mosfet Class AB solid state amplifier.

The smaller 2-way speakers literally came alive and sounded quite different with a more robust amplifier. Smoother highs, better silky midrange, bottom end was all there. Real iron and current driving them. No subwoofers, not necessary at all.

Like you experienced - it really showed what the speakers were capable of being. All the bases were covered at low, medium, high volume level listening. There was never a need to turn them up, they sounded very nice at low-med levels once they were being driven by this amplifier.

Cbrez, you have a nice system. I remember coming across it at some point and it was one of the reasons I was thinking about the XA25.

I have the Ray Reserve tubes and Gold Lion 12AT7s. I thought they were a nice improvement over the stock tubes, I think they helped tighten up the bottom end and eliminated a small amount of treble glare I noticed with the stock tubes - although to be fair, the amp and tubes were also probably still burning in and settling at that point.

Lot's of thoughtful comments here so thanks to all who chimed in. After reading the comments, I do think the XA25 might be a little too warm for my tastes - even though it may be less warm than some other Pass offerings. 

My room is not very large - 14x19 with pretty standard ceiling height. I really hadn't been too concerned about the XA25 power since it has high current output and is very conservatively rated 50W at 0.01% distortion. However, I do like to turn up the volume some times and I wouldn't want to miss that.

Given the power issues and possible warmth of the XA25, I am leaning towards sticking with Class AB and it sounds like Audionet is one of the best options in that area. I had indeed been eyeing the Amp 1 V2 for sale here. I noticed the input impedance is 37 kohms. I think the LTA is 50 ohms so it should be okay? Any concerns about impedance mismatching or the pairing with the LTA?

Hi. I have a Pass Xa25 and love it. It is very close to my tubes, CJ Classic 62 SE, my Heron mono blocks a d Resolution Audio mono blocks. It has a purity and ease that the others do not. My speakers, Penaudio Cenya Supreme, are 86db and 4 ohm. My old room was 15x33 and I never needed more power. I would say that the Xa 25 is an amp to keep.

@bluethinker Definitely many factors and glad to hear you are enjoying the Gryphon. I did my tube rolling before I even heard about the “Ray’s Tubes” that LTA is using as upgrades. I bought some Telefunken ECC801s and CBS/Hytron VT-231 (6SN7) and they were a huge improvement over the stock LTA tubes. The LTA was terrific before, but next level after.

@cbrez - I ended up purchasing a used Gryphon 120 which does 240 watts into 4 ohms. It was at that moment that I realized the full potential of the Dynaudio Heritage Special speakers. They are fantastic speakers and I just feel they really open up when driven with more power. 

Part of my issue might be my room, however. It's a very large room with high ceilings, so I just might need more power because of the space... 

BTW - What tubes are you using with your LTA preamp? I know LTA is offering those new "Ray's Tubes" which I've been curious about... 

@sfpeloton - I guess room size would be an important consideration. How big is your listening space? 

@zlone - I've wondered about that Audionet amp you've got now! Can you share more about your impressions of it? 

@fastfreight Yes, I am a converted Audionet fan now. I might go with the monos someday, but for now the Amp 1 has been great. Responding primarily to confirm your description of the Audionet sound:

The Audionet gear is lightning fast, with super transients and dynamics, yet so resolving I call it the sparkle.  They are NOT over etched or too bright.  Listening is engaging and non fatiguing.

This is so true. I refer to it as 'just right'. I hear GTT's room at Axpona this year and had similar comments. And yes, you can find a good deal on a demo Amp 1 on his site.

I have not heard the Hegel to compare, but I do drive the Heritage Specials with a Pass XA25. I also own the same LTA pre (with rolled tubes). I have no issue driving the Dynaudios to listening levels that are satisfying to me, though I am not into listening at high volume levels.

I feel that the combination of the Pass and the LTA works extremely well. The LTA is not at all a classic sounding tube preamp, but is very dynamic and natural sounding, but not lush (like an older CJ for instance). The Pass is a little on the warm side and it pairs well with the LTA. 

Also, the HS speakers are a nominal 4 ohm load, so you are getting the additional power that the Pass can put into lower impedances. And as it has been measured when reviewed, the 25 watts even into 8 ohms is very much underrated to what the amp can actually do.

In my room, the setup has responded very well to every upgrade I have made, adding resolution, precise imaging, microdynamics, and open soundstage, along the way. Timbre has always been good, but got even better when I upgraded the LTA tubes this year.

Tons of choices as others have indicated,  but I’ve been very happy with this combination.

+1 @zlone , I did not see your post prior to mine.  Yes the Audionet Pre G2 is amazing with their amps also.  I traded mine in when I got the Stern / Heisenbergs. My first taste of Audionet was their entry level Pre1 G3.  It blew away the Classe Pre I was using at the time, and opened my mind and ears to the sound I wanted.

Maybe the OP will go for your Audionet Stereo Amp1v2 and you can get the Max mono amps!!!  :)

Hello @sfpeloton ,  Good Morning!  You do have a nice system and have paid a lot of attention to your digital front end!  I am a huge fan of Audionet!  I have owned the mono Amps, mono Max Amps and now the top dog Heisenbergs.  While the Heisenbergs are amazing, the Max amos give you most of the Audionet sound at a more reasonable price.  My friend owns the Humboldt integrated, which is also stunning, but I like the Max amps  better.  I have directly compared to Classe, Parasound Halo, Hegel and Pass and think the Audionet amps and preamps are special. To me, the other AB amps I have heard are dark, dull and uninspiring (and the Hegel is perhaps the best of these).  The Audionet gear is lightning fast, with super transients and dynamics, yet so resolving I call it the sparkle.  They are NOT over etched or too bright.  Listening is engaging and non fatiguing.  I run the Heisenbergs with their Stern preamp, and the Maxs with my Mola Mola Makua preamp w onboard Tambaqui.  The Mola Mola is a touch warmer, but still a wonderful match.  Audionet amplification with your tube pre should be stunning.  I know Bill at GTT has been sitting on a demo Audionet stereo Amp V2 that I have been tempted to get for my vacation home. Happy Holidays! Ken

I agree with Souix.  I didn’t find the pass all that resolving. I would go with the Clayton‘s.

I agree with the others that the XA25 might not have the depth you need to drive those speakers. I also agree that the Coda #8 would be a good choice. That said, I recently swapped out my #8, for a new to me Audionet Amp 1 v2 and a Pre G2. I was using a Pass XP-12 with the Coda. I am not sure how the Audionet amp would be with the LTA, but it is magical with the G2. I will be selling the Coda shortly if there is interest. 

For your speakers if you want Class A I’d take a hard look at these Clayton Audio monoblocks.  At least as good as the XA25 and lots more power, and at this price used if they don’t work you could sell them for little/no loss.  Personally I’d take these over the XA25 in a heartbeat, but that’s me.  Clayton no longer sells new amps, but apparently the designer still services them.  Just another option, and best of luck.

https://www.usaudiomart.com/details/650127705-clayton-audio-m-100-class-a-monoblocks/

@sfpeloton - I concur with audphile1. I also own the Dynaudio Heritage specials and LTA preamp. I’ve driven the Dynaudio’s with a Luxman 590axii class A amp that has similar power output to the pass labs XA25. It’s just not enough power to drive the Heritage speakers to their potential.

The Coda 8 would probably be a better pairing. 

I read that too about the XA25 being a bit more lively than the XA30.8. 
I owned the following Pass amps -

X250.5 with B&W N803 and Dynaudio S5.4

XA30.8 with Martin Logan Montis and Wilson Sabrina 

X260.8 mono blocks with Wilson Sabrina

The sound character of Pass amps is warm, luscious, full and forgiving. The X seried has a bit more bite and dynamics than the XA30.8. 
I then simplified my system and went with an integrated Coda CSiB and Boulder 866. I loved the Coda and I think it would be a great match with Dynaudio. It’s articulate, musical and fast. Not as forgiving as Pass but not brutal when it comes to bad recordings. Reason why I think No.8 will be better than XA25 is Coda’s ability to deliver high current. The V1 has 18 watts in Class A, 150 into 8, 300 into 4 and 600 into 2. It is still worth to try XA25 if you get one used and flip it if you don’t like it. I love Pass amps and preamps they just play music. There’s no hint of harshness and the presentation is not analytical. I just don’t think the XA25 is enough for your speakers. If you can swing X250.8 it would probably be a better amp. 

Thanks for the input. To clarify, the Bricasti is still running balanced to my LTA preamp with Lundahl transformer conversion in the preamp and then SE output to the Hegel. I agree it is best to keep the Bricasti running balanced.

My impression from reading was that the XA25 was not as dark as the XA30.8, but your comment is why I am asking for feedback since that seems to be what some describe as the Pass sound.

I have been considering Coda as well. My take away was that the XA25 was possibly similar to the Coda S5.5 in sound signature and overall specs. XA25 is closer to 100 watts into 4 ohms with distortion less conservative than 0.01%

Highly recommend running the Bricasti M3 balanced. With XA25 it will not be possible. Plus it may be warmer than the Hegel. I had XA30.8. Never heard the 25. 
If you want good Class A that won’t darken the presentation try Coda No.8. Or keep the Hegel. Also the Dynaudios love power and sound best when cranked up. Just keep that in mind with lower power XA25.