Pass Labs Amp X350.5 or X350.8 anyone compare?

I have searched for some opinions as to the sound quality comparison between the older Pass Labs X350.5 which I own and the newer X350.8.
It looks like the .8 does not operate as much in class A as the .5. But, that doesn't tell the story.
Anyone have a chance to listen to the newer X350.8? And if possible how does it compare to the X350.5?
I'm also interested in this. I believe the info on the Pass website claims that the .8 models operate MORE in class A than the .5.
I have compared the XA60.5 to the new 60.8, I would assume the same changes in sound are across the board to varying degrees despite the different series.

First off, the amps are quite different looking (although typical Pass labs look), bigger, longer, heavier, totally different binding posts and back panel. Build quality seems a bit better. For sound, the background is much blacker, deeper and wider. The window into the sound is endless. Bass is far more authoritative especially at lower volumes. Textures, tones and body are all improved significantly. Quite frankly, they could have come up with an entire new nomenclature as far as I am concerned. The upgrade is not insignificant. As good as the 60.5s were, the 60.8s are just head and shoulders better in every aspect.

I would bet the X series amps offer the same overall improvements.
Great question! I would like to know about this as well.
Owned a brand new 350.5 and ran it for 30 days to break in and it still sounded lean and bright to me. I was surprised as everyone told me how great sounding the Pass amps were. My old Jeff Rowland Model 9's of ten years ago easily outperformed the Pass in the areas of musicality, bass control, extension, etc. I dumped mine after two months of giving it time to settle in. I did audition the Pass 100.5 and that amp is far more musical than the 350.5 and had I stayed with solid state that is the Pass I'd have kept.
From The Pass Labs website.
In Class A the X350.8 35 watts.
In Class A the X350.5 40 watts.

Hifimaniac, odd that you would describe the Pass Labs Amp as bright. But I guess based on way we assemble our systems anything is possible.
I have the Eggleston Works Andra 2 speaker and with the Esotar tweeters they have never sounded bright.

To upgrade or not that is the question...
Interesting that the X350.8 loses 5 Class A watts, while the X250.8 gains 10 from 15 to 25 in Class A.
Jl35, I agree with you it does sound strange.But, I just talked to Pass Labs and Reno HiFI and both said it is minimal in actual usage and the newer technology uses it more efficiently.
Anyway, I ordered one (X350.8)to compare to my Pass Labs X350.5.
So, in the next few weeks I'll be able to post my comparison.
Pretty cool. Congrats on the new amp. I look forward to your comparison. That should be fun. I wish I was over there to hear both side by side. :D
Dave_72, Thanks, I have been so pleased with the Pass equipment that I doubt if the newest version will disappoint.
You're welcome, Ozzy. I'm considering Pass Labs as an upgrade (from another brand) myself. Just the amp though, I'm not too crazy about their preamps...
Acurus, Thank you for your comments. Really based on your experience is what prompted me to go for the newer version. That plus Reno HiFi is excellent to work with.
Ozzy, I too look forward to your impressions of the new amp.
Whitecap, thank you. I should have it next Tuesday. Probably won't be able to play it much until perhaps that weekend.
The pressure is building Ozzy, lots of us waiting for your report...I know Reno recommends and 8 day break in, at least for the .5 series...
I'm used to pressure.
I just received my X350.8 Amp and I am now listening to it...
Ozzy, I'm breaking in XA-160.8 monoblocks. Suggest at least 40-50 hours of time with music before forming critical judgment.
Dgarretson, Thanks for the info. I'll give it some time.
That's cool, Ozzy. Is there anything you like about it so far, or is it too early to tell?
I used to own Pass and Eggleston Rosas. Pass and Eggleston are a great combination. I found the more power I had with my Egglestons, the better they sounded.

My buddy Madfloyd just upgraded from the XA160.5 to the XA160.8. I heard both in his system two times. The .8 had much better control of the Alexia's bass and the overall sound was more transparent. I think the .8 also has lower noise so more information came through. I really liked the .8.
Dave 72, First impression. Pretty good...
Deeper soundstage, better bass and treble. Even at this early stage, I'm sure its a keeper.
Hello Ozzy. Can you compare it to the XA series if you have heard them? I'm looking for the liquidity and naturalness of the XA but the dynamics of the X. I'm actually waiting on a X350.8 too. Have owned/demoed the X150.5, X250.5 and the XA100.5. Many thanks.
Dave 72, First impression. Pretty good...
Deeper soundstage, better bass and treble. Even at this early stage, I'm sure its a keeper.

Thanks for that, Ozzy, it definitely helps me out. I look forward to your full review...
I've had the Pass X350.8 plugged in now for about 5 days. Playing time is about 10-15 hours.
The sound stage is deep but seems a little dark. That is, with little air around the instruments, and the treble seems to be a little muted.
Though this somewhat concerns me, it is probably normal for the amount of time on the Amp.
This was my experience as well. The large PS caps need more time to form. Keep your chin up for at least 40-50 hours of signal.
Thanks for that, Ozzy. Keep up the good work!
Just an update on the X350.8. I have about 70 hours of actual playing time and it has been plugged/turned on for many days 24/7. I'm really not sure how many hours it will take to reach optimum, but to me it seems like it is there.

The Amp is much different than the X350.5. The soundstage is much deeper with a darker (more Analog?) presentation.
Has anyone else purchased the new .8 series Amps? understanding is that the .8 amps are supposed to have *more* life in the upper frequencies. Anyway, keep up the good work Ozzy!
Ozzy, I did not hear the .8 as darker, but there was definitely more control of the
lower freq. and extension. That may be changing your perception of tonal
balance. The Egglestons need lots of power so it should sound more dynamic
with a cleaner more articulate base and more detail because of the lower noise
floor. But I compared the XA160.5 to the XA160.8 and am not really familiar
with the X series. They should be fully broken in by now.
Thanks for the comments. I also am running direct from my PS Direct Stream to the Amp. The Direct stream is known for its analog presentation.
I sense as well that the XA-160.8s have mostly settled in by 75 hours. I can see how some might perceive the .8 palette as slightly dark or tilted down. However this is deceptive, as there is also ginormous resolving power in the treble and upper mid-range, that emerges without over-emphasis from the most surreal black background that I've encountered in an amplifier. I'm still getting used to it, and am not yet persuaded whether the effect is entirely natural or subtractive. But the attendant absence of distortion, ringing, grain, and glare is definitely a good thing, and the system has never sounded so smooth and seductive.
Hmmm...I'll have to say I don't like a subdued upper midrange and treble. If that's the case with these .8 amps, I'm no longer interested in them.
Dave, I did not get the impression of a "subdued upper midrange and treble" when I compared the XA160.8 to the XA160.5 in Madfloyd's system. He has Pass XP30 and Wilson Alexias.
Dave 72, I wouldn't say the midrange and treble is subdued. Its just different from what I have been listening to over the past several years. To go from the front row to perhaps the middle is the difference in my opinion,
When I first upgraded from XA160.5's to XA160.8's I did think the highs were subdued. So did at least one of my audiophile friends, who told me he preferred the highs from the .5's but overall preferred the .8's because it had more 'meat on the bones'.

There was a LOT more bass energy in the .8's and this finds it way up into the midrange where it provides a thicker, more palpable presentation.

It's hard to say whether the treble of the .8's actually has less energy or whether the .5's simply have a thinner (more recessed) midrange. The latter is the impression one gets when going back from the .8's to the .5's (I had both amps in my system for 2 months).

I ended up switching speaker cables and now I don't find any loss in high frequencies (system synergy!).

Hope this helps.
It's an endlessly interesting hobby. This evening I removed an Afghan rug from between the .8 amps(on Stillpoint Ultra SS with coupling bases) and Merlin VSM(on Stillpoint Ultra 5). This redressed the frequency imbalance with a more prominent upper midrange and HF, with improved LF definition. It's now about as perfect as imaginable. Star Sound Apprentice platforms are en route for comparison.
Ok, thanks guys, I was worried there for a bit, lol.
07-05-14: Dgarretson
It's an endlessly interesting hobby. This evening I removed an Afghan rug from between the .8 amps(on Stillpoint Ultra SS with coupling bases) and Merlin VSM(on Stillpoint Ultra 5). This redressed the frequency imbalance with a more prominent upper midrange and HF, with improved LF definition. It's now about as perfect as imaginable. Star Sound Apprentice platforms are en route for comparison.
So after all the tweaks and $$ upgrading to .8, now it sounds like .5? LOL!
Great information guys, I also thinking about upgrade to the 350.8.

In 5 years of time using many different Pass Labs amps, I did learn one important thing.

With th best powercables and interconnects you can get a superior level out of an Pass amp.

This means it is very easy to loose a lot of the quality an Pass amp can give. So most people spend a lot of money on an Pass amp and don't use a big part of the quality it is capable to give.

You need to understand the properties of Pass Labs. This is including their weakest points. These you need to improve with the right properties of cables ans sources or even with pre-amps.

The best sound possible only will come to the surface when you have created all the properties togheter in a set. Often a set is incomplete. Why it is incomplete? Because most people don't understand what is missing.
After 80+ hours of actual music playing time and several hundred hours with the X350.8 turned on, I can honestly say that the .8 Amp does have superior sound quality over the X350 .5 version.

That is; better bass performance, along with dynamics from a blacker background. There is no lack of high frequencies and the midrange is great! I am going to keep the X350.8 and trade in my X350.5.

Comparing this Amp new out of the box to an Amp that has been used for 5+ years was a little tiring. Both of these Amps have different presentations. The .5 has more of an up front sound with the upper midrange being dominate. So, through the years of ownership I have adjusted my room to smoothen out the sound.

The .8 soundstage is deeper but with all of the frequency range being equal. At first, I thought there was a lack of treble, but after listening for all of these hours, what is there, is more blackness between notes. When a cymbal is wacked it is startling.

To those who like using banana’s, finally this Pass Amp can accept them and also bare wire!
Mmmmm.....I like banana's too!!
Joecasey, The .8 monos are my first Pass amps. I've heard .5s only at shows, and too long ago for comparison.
Thanks again, Ozzy. So I take it a long break in time is key to success. My current speakers (JBL S4700s) were like that; they were dreadful out of the box, and now they really rock the house. However, it took at least 200 hours of break in to even get close to where they are now. A word of warning to any prospective buyers out there!

Anyway, it's good to hear that the new Pass Labs amp is a winner. Again, I was worried for a minute there. If it were me, I probably would have had buyer's remorse! lol.
@ Dave_72

Pass Labs is overkill on JBL speakers IMO.

Get decent High End speakers first.
@ Don_c55

JBL S4700 is maybe not the most refind loudspeaker. This 20.000 dollar set of speakers can still be a good combo with Pass labs. Because you need the power, control and musical sound for the JBL S4700.
Ha! Clearly Don_c55 didn't know anything about the actual JBL speakers that Dave_72 owns. $20,000 is not mid-fi.
Thanks Bo. Exactly. I dunno what this Don_c55 guy is talking about. I doubt he has heard the high end JBLs thoroughly. The S4700s *when broken in* can be very delicate indeed. And furthermore, they fit my listening profile as I listen to mainly classic rock, blues, and free jazz. With a little metal and punk on the side. So basically, I like them, they're the right speakers for me, and that's all that matters.
Thanks Cal3713, I appreciate that.
Yeah, the irony of someone with a $5500 retail set derogating the terrible quality of the $20000 speakers is just awesome. So many egos in this place... gotta love it when they get squeezed a little (sorry Don).

In any case, I'd still like to hear any additional reports on the .8 series... please keep them coming.
We all make mistakes. It doens't matter!!