Upgrade from Pass Labs XA30.8 to X250.8. Worth it?

I am getting ready to make some upgrades to the system. I currently running a DAC into a BAT51SE, then a Pass Labs XA30.8, then finally into Decware DM947 speakers (don't worry if you've never heard of them; not the last word in speakers, but have been doing a solid job for about 5 years now.)

I am contemplating moving up the Pass Labs amplifier line, and the X250.8 looks attractive. I would like to hear more bass authority and definition, but I don't really want to sacrifice the mids and highs of the 30.8. 

I would love to hear some of your impressions of the X250.8, especially if you are able to make some direct comparisons to the XA30.8. I've spoken with both Mark at Reno Hifi, and Kent English of Pass Labs; both are wonderful and informative people. What I am interested in now is the opinions and experiences of end users of either of these amps. 

A few months ago I listened to both (250 & 30.8) and some other amps driving a pair of Danish, not very sensitive, spkrs. Between the two, the 250.8 had much more driving authority but the 30.8 won on timbre and sound quality overall. If I remember correctly, your Decwares are xoverless and very sensitive, so I cannot say if the added power will give you what you are looking for since the 30.8 by itself should be powerful enough to drive them well. Perhaps repositioning your spkrs could help? Then again, one can never have too much power, can one:)
Really hard to find some specs on the DM-947's but I found this
" its highly sensitive with a smooth impedance curve"

If this is true, stick with the XA30.8, it will sound better so long as you don't want to throw a rock party with it.

Cheers George 
Greg, thanks for the comparison. Exactly on point. I just wonder how many people make the switch after hearing them side by side?

George, I did some research a while back on the DM947’s. I tracked down what I believe is the actual driver for the speaker. It’s called the “Silver Flute.” 

The drivers themselves appear to be relatively inexpensive (hence not highly advertised), but they do sound a lot better than the parts price suggests. They do have the benefits of a crossoverless wide-bander.

You can find them here: 


If you're sticking with sensitive or ultra sensitive speakers, you might want to investigate, instead, the Pass XA25.  Some people who've heard it and the 30.5 prefer it.
willrich47 -

Another +vote for Mark and Kent- those guys know Pass Labs amps.How do you like the B.A.T. / Pass Labs combo?
Happy Listening!
hk-fan, I agree. If you are going to use hi-efficient speakers stay with the XA amp.
@twoleftears I was once intrigued about that particular amplifier. I asked Mark at Reno Hifi about it, and he indicated that the 30.8 does just about everything better than the XA25. Though admittedly, I haven't compared the two. I did own the 30.5 before the 30.8, and could compare those two if you'd like! 

@jafant I was fortunate to find a copy of my B.A.T. on Audiogon. It had been recently recapped and was in great condition. I came from a tube amplifier. The B.A.T. has a slightly warm and dark sound to it, which I really like. I am always striving for simplicity in my system, and I have taken it out a few times to decide whether I could "live without" it. As soon as I remove it from the audio chain, I immediately miss it. I am definitely a proponent of having tubes SOMEWHERE in your audio chain. Love that sound!

@hk_fan Thanks for the response. This is why I posted here. To get a wide variety of opinions on the topic, even if they are conflicting. I am a bit confused though because Mark seems to think that the X250.8 is a solid upgrade from the XA30.8. Kent seems to like the X250.8 very much too (claiming to keep that one at home a majority of the time) but admits that it isn't as warm as the 30.8. I'm hoping to find some of those "happy customers" Mark was referring to; or even some unhappy ones. 

@snopro the sentiment is not lost on me. I am still trying to wrap my mind around why bigger AB amps often times have better bass, even though the output may be the same as a class A amp. Even more within the Pass line. Moreover, why does 1 Class A watt from the X250.8 sound different from 1 watt from the XA30.8. No idea, but trying to learn! 

Thanks all for the responses so far!
The X250.8 may have better bass, but bass is easy - the liquidity and smoothness of the XA in the mids and highs is what's difficult.  If you want bass, keep the the XA and buy a quality powered sub.  Completely serious here.

I am still trying to wrap my mind around why bigger AB amps often times have better bass, even though the output may be the same as a class A amp.

What is most likely happening here is that the fully Class A amps require so much constant DC that the power supply just doesn't have enough on tap for the powerful bass hits.  It requires an enormous amount of power supply capacitance to supply enough "smooth DC" power for that constant 30 watt Class A sink -- that it's only just enough to carry through for normal music.  When bass frequencies hit, it will pull even more on the power supply, which is just treading water enough to keep the voltage up (though I suspect voltage will dip anyways on the high power bass hits).  I suppose the exception would be very huge amp, such as the XA200 monoblocks, or something like a Krell FPB300+ monoblocks.

On a large Class AB amp, such as X250.8, the power supply is sized larger than the XA30 with a larger transformer as well so that it can sustain that 250 watts per channel.  However, you hardly use much of that, probably 5-10 watts constant draw during normal music and when the bass hits, the power supply transformer and capacitance has enough current on tap to push that bass frequency waveform through the speaker before it needs to draw on the main A/C current to recharge the power supply caps.  The power supply is able to draw A/C voltage at 60 hz, which is generally fast enough to keep the power supply full for low bass frequencies.

Post removed 

kosst, honestly, I really don't trust anything you say anymore.  Now if almarg came in and corrected me, I would believe him.

I do know that Class A amps have a much larger constant A/C draw.  In Class AB an amp might have an idle current of 63 watts, but if biased to something like 30 Watts Class A, the constant "idle" A/C draw may go up to something like 160-170 watts.

Post removed 
You should consider the X350.8. It is in a whole new league compared to the X250.8. It has all of the tonal qualities of a class A amp but with
detail and pure strength when needed. It is probably their best amp for the money.
@browndt that amp is also intriguing. There’s one listed on Audiogon right now. Do you have personal experience with those two amps X350.8 and X250.8? 

I prefer the X250.8 to the X350.8 and the XA30.8 .  you really just must listen, all are excellent but different
have you considered the xa 60.8? I haven't heard the x250.8, but I did have an x250.5 and moved to the xa60.8 and it was a solid upgrade. 

if you like the xa30.8, maybe the 60.8 is what you want
@hk_fan You’re not wrong. Indeed, that is how my current setup works. I have an SVS SB-16 picking up the lowest frequencies. 

Part of getting a sub integrated is making it not call too much attention to itself; just picking up the frequencies that are lacking in the speaker itself. Most of the bass I am hearing in my system comes from the XA30.8. 

I remember one of the very first “hi-fi” systems I heard 5 or so years ago had a very tactile, visceral feel to it. No matter the subwoofer I use, the 30.8 is not going to produce that visceral aspect of the music. 

I would agree, the mids and highs are second to few. My hope is that further up the Pass line somewhere is an amp that has more of that power, but with the finesse in the mids and highs that the 30.8 has.
Post removed 
I’m expecting a set of XA 60.8s from Reno Hifi to arrive in a few days. I too, have an XA 30.8. Although I’m expecting the bass to improve, I’m really seeking improvements in imaging, sound staging and a greater sense of ease, which my discussion with Reno Hifi and my reading of the description on the Pass Labs site have led me to expect. Based on everything I’ve read and heard, and especially John Atkinson’s review of the XA 60.5’s, I’m tempted to think that the XA 60.8s are their best sounding amps. I don’t see how their more powerful XA’s could be as good in terms of finesse, but again that’s my conjecture. I have the lower bass covered with my Vandersteen Quatro CTs. I can’t wait to hear them!
Post removed 

I used to own the XA30.5; it was a great amplifier. It replaced my Decware Torii Mk IV, which I was sure, was going to be my ‘terminal amp.’ When I got the XA30.5, I thought I was taking a huge chance on it. I didn’t expect it to perform well against my valve amp and figured there was a 50/50 chance I would be disappointed and sell it. I was surprised to find that the Pass Labs XA30.5 eclipsed my Torii in almost every way. 

The XA30.8 sounded different in a couple of ways. For starters, it sounded great cold! Maybe better than the XA30.5 warmed up. 

There are plenty of other differences between the two amps. For example, the 30.8 is darker, much smoother, clearer, images better, and voices may be pulled back just a hair. It's got more mid-bass, which I like a lot (reminds me of my tube amp). Its bass is overall much punchier, tighter, clearer. The 30.8 sounds much more powerful overall.

On top, the main difference between the XA30.5 and XA30.8 is that the XA30.5 has a 'sweetness' on the very highest frequencies. I don't hear it with the XA30.8. I liked the sweetness on the XA30.5, but there are bound to be a couple of gives and takes. 

I can see why you like the 30.5!!

Keep the 30.8 and upgrade your speakers.  You are already driving those speakers with a world class amp.  You were pleasantly pleased when the Pass outperformed your Decware amp. It is the same with your speakers.  Yes Decware makes very nice affordable equipment but spending more on a amp will not automaticly give you better sound. Budget for new speakers and keep your current amp and preamp.
@bobheinatz honestly, that is really the heart of the decision I am making right now. I’ve got a pretty good offer on the X250.8 that I am interested in taking. But for the same out of pocket price, I could also get a pair of Tekton Double Impact speakers, which everyone is raving about. (Incidentally, Tekton’s HQ is not far from where I live and they’re willing to let me come in for a listen.)

My goal is to add a bit of slam to the already great sound my system produces. The Double Impacts are nearly 4 times as sensitive as what I’ve got, but does that necessarily translate to more of the “slam”? I don’t know. 

I know the X250.8 will probably give me more of that and probably a bit more detail and space too. But like you intimated, my mid-fi speakers are probably the limiting factor in my system. I’m just trying to determine what gives more of what I’m looking for: the speakers or the amp?
If you would like to keep XA30.8, maybe a high sensitive speaker with powered woofer is a smart move. For example paradigm 9H with sensitivity 93-96db 
I think a key question is how loud you drive your speakers.  Most people are too focused on amplifier power.  Even Nelson Pass seems to agree with this, given his side company First Watt!  If you are not listening at ear piercing levels, I would doubt you need an amp upgrade.
I have intimate experience with both the XA-30.5 and the X-250.5 as our main stereo amplifier.
Our system, at the time, was:
Wilson Watt Puppy Va speakers, Meridian 800 transport, 861v6 processor, MIT Oracle Max2 Balanced interconnects, MIT Oracle MAX speaker cables, MIT Oracle MA Digital interconnect, Sound Application RLS power conditioner, CH Acoustic X-20 power cords, a single Pass XA-30.5 (for stereo) and 3 X-250.5 amplifiers (for theater). 
We now have 3 Pass X-250.5 amplifiers for theater and a pair of XA-200.5's for our integrated stereo system. Currently using Sasha I's, our setup emphasizes stereo over theater.
I state our system so one can realize it's level, which can easily reveal the character of system changes, recorded quality and the acoustic of the recorded venue.
For a long time, we listened to the XA-30.5 as our primary stereo amplifier. The X-250.5 wasn't a match. While the 250.5 had better bass, and (as Kent English and Mark from Reno HiFi state) was "faster," the 30.5 was dramatically more coherent. The sound stage and imaging were much better defined / fleshed out, coherent and much more believable. We were able to easily define the acousitc venue and the performers subtle cues and expressions. EVERYONE who heard the comparison easily picked the XA-30.5 as their preference.
When we were selling one of our X-250.5 amplifiers, I was concerned the buyer would want to hear the XA-30.5 because they would have changed their mind!
I'm a educated and licensed Chemical Engineer, and I learned a long time ago to hear and listen to equipment before making any assumptions or "educated" presumptions.
I believe the XA-30.5 is one of the BEST bargains available! It operates in class A up to 30 watts and puts out just over 200 watts in class AB. Perfect - no but what performance for it's price.
Just my experiences for your thoughts.
I have yet to hear an XA- .8 amplifier. Maybe one day we'll get an XS amplifier :-).

I have an x250.8 and have enjoyed it for more than a year first with Magnepan 3.7 speakers and now GE Triton Reference.  I have not heard the XA30.8 but thought you might get some useful information from this review of the XA60.8 vs. the X250.8.  Good luck on your decision. 

For some reason the link didn't post, but you can find it if you google X250.8 review and look at Terry London's Hometheater review
@tjassoc thanks man! The comparison is helpful. There are so many opinions out there, some informed, some not, it’s difficult to know for sure without hearing. At this stage I think it best to aggregate the opinions I am getting to make that informed threshold decision: whether to order the amp for the in-home trial.

Although not the exact amps I am asking about, your comparison does carry a lot of weight. 

I’ve heard great things about the 200.5’s too. I assume they bested your 30.5? ;-)

thanks for the advice. I thought Mark at RenoHifi’s unsolicited reference to that review was interesting as well:

“Terry London's review says that the X-250.8 and XA-60.8 sound "the same."   I don't agree that they sound the same, but they are certainly very close in sound.  The X-250.8 has more power and is more economical, so for almost everyone, the X-250.8 would be the way to go.  The XA-60.8's are at least $3000 more than the X-250.8.”
Will - regarding the 200.5's compared to the 30.5's, I asked the same question to Kent English and he chuckled and said, at one time - the 200.5's were the best amplifier we knew how to build so yes they are significantly better than our introduction XA line 30.5 amplifier. Of course, he was correct.
Summarized, the 200.5's do everything very well.
Different people are sensitive to different things. I remember consulting with an audiophile here on Audiogon when considering the Lamm 1.2 monoblocks. After hearing them on an almost identical system to our own, I realized the are slightly bass heavy. After reading more on the recommendation, I learned the person recommending the 1.2's was a bass player.
The same is true for video - something that may be very objectionable to one individual (black levels to me) might not even be an issue to another individual.
For me, creating the illusion of a live performance in our listening area is everything. Because our set up is not in a large room / hall, I prefer small acoustic venue performances. Our system is pretty convincing. Here, the 200.5's have a natural acoustic that recreates the performers, the acoustic venue and their own performance convincingly with little, if any weaknesses.
I also listened to Spectral amplifiers (when I listened to the Lamm 1.2's) and the Spectral were a little dry - that is they didn't have the same natural acoustic of a real performance the 200.5's did.
Similar but being super critical, were Dan D'Agostino's Momentum monos. They're the closest (I've ever heard) to the Pass 200.5's but were just a slight bit shy of the natural acoustic of a real performance. Does this matter, well - at this level and cost of equipment - to me - yes. (I've read the Momentum's bass betters the 200.8's but the bass wasn't as critical to me)
All this is just my opinion and what I prefer. You may have different tastes. Ultimately, for me - it's all about re-creating a live performance in our listening area. Our system does that amazingly well, we've tested it with our son playing his sax in our listening room and then playing some David Sanborn (not an audiophile recording). The acoustics are almost indistunishable - almost! Now, if our son could play like David Sanborn . . . 
I live not far from the Tekton Design home office. I went in today to have a listen to the Double Impact speakers. At first listen, these were incredibly detailed speakers that had most of the improvements I was hoping for in an amplifier upgrade. 

I think my next purchase will be from Tekton. I’ll revisit the amplifier question a bit later. 
@tjassoc I’ve read your last post a few times. I’d love to get my hands on a set of 200.5’s. Every review I’ve read makes me think those are THE amps to own. Perhaps even over the 200.8’s. Thanks for the insights.
Will - enjoying music is what it's all about.
whitecamaross has a LONG amplifier review post going. It also includes pre-amp's and speakers. He's reviewed the 200.5's and was supposed to review the 200.8's but the transaction was canceled. He hasn't posted in a while but I'm confident he'll continue his record setting review thread.
Glad to share - good luck and happy listening :-)
@willrich47 I have driven my former Tekton Double Impacts and current DI SEs with the Pass XA30.8 (and the XP20). It is a very good pairing for Tekton’s speakers.

I do not believe you will need any more power than what the 30.8s have on hand. In fact, I doubt you will utilize more than a fraction of the Class A 60 Watts into 4 Ohms for the Tektons.

My recommendation is to keep the 30.8 and put what you have set aside for a replacement amp towards a high quality power supply/conditioner. The upside of a quality power conditioner is that it IMPACTS all components in your system.

With respect to the Pass XA30.8 based system...my Synergistic PowerCell 12 SE transformed my system’s performance to a level that had I chosen the PowerCell first (instead of evaluating amps and subsequently choosing one) I would have been reluctant to explore other amps.

You haven’t posted a systems page, so I do not know if you already have a power conditioner. If you do not, I highly recommend exploring the choices available and pairing your choice with a top notch power cable. All the best!
Will - we also use a high end power conditioner and some of the best power cords available. Clean power transforms a system's performance - highly recommended.
@david_ten thanks for the report on the exact system I want to upgrade to! 

When I visited Tekton Design, they had their DI’s set up with a tube amp. The logo said “Raven” on the front, and it appeared to be using a pair of EL-34’s for each channel. Maybe 25 watts or so. I didn’t get a close look.

Through the DI’s, that tube amp seemed to have some punch and grunt. I know how those kinds of amps typically sound. They usually sound a bit weak on the low end. I know the XA30.8 is going to make the Double Impacts sing!
@tjassoc I agree with both of you on the power conditioner. It’s definitely on my wish list.

I’m in the middle of a new home build right now. One thing I wanted in the home was dedicated 20A circuits for the stereo. I even increased the amperage of the breaker box just to make sure I’ve got plenty for the future. 
there are many Pass dealers that do not use power conditioners, so be careful  before you buy...
I've tried several conditioners on my amplifiers and always preferred them without.  I use dedicated 20A circuits to my JC1's.
Our Sound Application RLS power conditioner feeds our front end components (Meridian 800, 861v8, 621, Oppo 205) via CH Acoustic X20 power cords. This creates a very noticeable improvement.
Our Pass amplifiers are plugged directly into dedicated 20 amp circuits with CH Acoustic X20 power cords. Plugging our Pass amplifiers into our power conditioner has the least improvement and we leave them plugged into their own dedicated 20 amp circuit. This, I believe is because the Pass amplifiers have a very well regulated & filtered power supply,

I thought I would follow up to give some closure to anyone reading this down the line. I always like to hear how people’s decisions turned out. Hopefully you do too. 


I purchased the Tekton Double Impacts, largely due to the advice I got from members here. While I am not ruling out an amplifier upgrade at some point in the future, I think the Double Impacts have had a more significant impact on my system, than an amp upgrade would have. 


The Tekton Double Impacts: 


The DI’s need some time to break-in. When I actually got my pair, I was surprised to hear they sounded “OK.” And by “OK,” I mean thoroughly OK, middle of the road, mediocre, and most of all: disappointing. But, it didn’t take long for the midrange to start opening up. The mid and upper range only took about 3-4 days to open up and sound wonderful. The bass, was a little different. 


I’ve been using an SVS SB16 subwoofer for a little over a year. When I started using the Tekton’s, it seemed apparent to me that the sound was improved with the SVS. A little over 30 days after getting my Tektons set-up, the bass seemed to change. All of a sudden, there was too much bass. I turned my sub down. A couple of days later, it seemed like too much again. This time I turned the subwoofer off. I eventually achieved the best integration with the SVS by crossing over at around 35-40 Hz. My RTA app on my phone says I had a relatively flat response down to 20 Hz. 


I remembered an email conversation I had with Victor Khomenko a while back. The VK-51se has two sets of balanced outputs on the back. I had asked VK if they could both be used at the same time. He said they could, but I had to be aware of the combined impedance of all the amplifiers attached to the VK-51se. 


My Pass Labs XA30.8 is relatively easy for my preamp to drive. The balanced input impedance is 100K Ohm. The SVS SB-16 on the other hand, is not as friendly; its balanced input impedance is 22K Ohm. I believe the combined impedance is found through the calculation (100 X 22)/(100 + 22) = 18K Ohm (I would appreciate if someone with some actual EE knowhow would fact-check me here).


As an experiment, I removed my SVS SB16 subwoofer from the system entirely. In my system, the DI’s start rolling off at about 40 Hz, so I lost some bass extension from the removal of the SVS. But what I gained was more drive and authority from the DI’s, and more color and clarity through the entire range. 


I don’t believe that I noticed this with my old speakers because they simply lacked the clarity of the DI’s, and did not have the same bass extension. With the old-speakers, the SVS simply improved the overall quality of the system. With the DI’s, there is a clear trade-off. Bass extension for overall sound quality (especially bass quality).


I have had my SVS completely unhooked from the system for about 2 weeks now. After about 1 week, I added it back to the system and found I disliked how simply hooking it up to the preamp affected the system. I quickly removed it from the system again. This has been an unanticipated side effect of adding the DI’s to the system, and has all but de-railed my plans for a second SVS-SB16 subwoofer. 


If anyone has some clever tricks for getting around this problem, I am all ears! 

@bobheinatz I think you were right ;-)

Just for clarity, the SVS SB-16 subwoofer is still the single best sub I've heard. I simply think the impedance drop is having a negative impact on the sound of the overall system. If I could use it without changing the load on the preamp so much, I think I would have some stunning results. 
Will, one thing you could try is a sub that provides high-level hookup from a power amp, rather than line-level from a pre. Two that do are REL and Rythmik. I don't know about REL, but Rythmik provides for both high (on binding posts) and low (on RCA jacks) inputs on their A370 and H600 plate amps, the non-XLR versions. On the XLR versions, low (line-level) only.
Haha, well, I just confirmed what I heard in this review of the BAT 51se: 

"The balanced output impedance was twice that specified, at 410 ohms over most of the audioband. This is low, though it did rise to a high 4.7k ohms at 20Hz, due to the size of the output coupling capacitors. (There is only so much room within the chassis for these high-performance but physically large components.) This will not be an issue with components having high input impedances, such as BAT's own power amplifiers, but it does mean prematurely rolled-off low frequencies with low load impedances (fig.1), such as those offered by some solid-state amplifiers."

Read more at https://www.stereophile.com/content/balanced-audio-technology-vk-51se-line-preamplifier-measurements

Now the question is, how do I fix it without replacing a preamp?
@bdp24 I was thinking along the same lines. I was hoping to do it without replacing the SVS. I've been searching for a high-level to RCA input converter, but haven't found a suitable solution yet. 

But you might be right. Maybe REL is where it's at. I am a little surprised that SVS doesn't offer this type of input solution, especially on their top-of-the-line unit. I have to think that more preamps would have this issue than just mine. Could be wrong though.