Pass Then vs. Pass Now

Congrats! Keep us posted. 

Update, pulled the trigger. An XA30.8 is on the way to me. Looking forward to testing it against my expectations. Will circle back to report on my impressions after I spend some quality time with it. Thanks again to everyone for chiming in with advice! 

Thanks! I am leaning towards the XA30.8 for many of the reasons stated here. I think I needed to hear someone say that it is in another league above the Rogue sound that I have been listening to (and enjoying - that Sphinx punches way above its class). 
 

I hate to burst your bubble, but the Sphinx doesn’t come anywhere near punching well above its class IME. My $250 Yamaha A-S500 integrated outclassed a Sphinx V2 by every metric, as has every other integrated amp I’ve owned, of which there are many. 
 

To say my Pass XA25 and Bel Canto preamp are in another league would be the understatement of the decade. An apt analogy would be comparing a VW Beetle (the Rogue) to a 911 Turbo. 

My experience with Rogue RP-1, RP-5 and ST-100 was similar - the sound would open up at higher listening levels. At lower volume it sounded a bit dry, less vibrant, less detailed and more restricted.
With Pass gear you get way more of what’s on the recording at lower volumes. Going up in volume gets you bigger images and more expansive soundstage.
My preference for the sound is to be close to optimal at around 80db measured in a listening chair. If you get extreme resolution at much lower levels in most situations it means at higher volumes you just won’t last long before the fatigue sets in and you want to shut it all down. That’s just the nature of the beast. So be careful there…try to strike that balance.

@theschwartz  Great discussion everyone. Really appreciate all the feedback and lively back and forth. 

@liquidsound you raise a great question. Being that I live in an apartment I can't really play too loudly. In fact one of the reasons I am looking to upgrade aside from a general improvement is that I find I need to turn the Sphinx up considerably before there is any weight and dynamics to the music so I am hoping to achieve a fuller sound at lower volumes.

While I can play music loudly, most of my musical enjoyment is at moderate volumes and if your speakers have challenges coming "alive" until they're played at higher volumes, perhaps it could be them, or possibly the equipment.  If you really like the sound of your speakers played at lower to moderate volumes, finding an amplifier that can do that could be the best thing.  If you can borrow an audiophile friends' solid-state amp to try and see if the weight and dynamics are better at your ;lower listening volumes, the direction may be clearer as to where to go with amplification.  What I have found with the Pass-Labs and First-Watt amps is that Nelson Pass has designed them with power supplies that are superb and when I have listened to them at lower volumes, the dynamics and "weight" of the music seems proportional to listening at higher volumes.  It gets back to I believe his design philosophy of if the first-watt doesn't sound good, how can the rest sound good ?  There are good reasons for my sticking with First-Watt amplification and I also have a superb 300-B tube amplifier (BorderPatrol S20) that rivals the First-Watt SIT-2.at low and moderate volumes.  However, the differences really come to light more with efficient speakers.  I can speak of this in more detail from my experiences in another post.  

@theschwartz yup ARC with Pass is excellent, you can’t go wrong. Take it one step at a time. Upgrade as time and budget allows you to do so but getting the amp first is the right move. 

FYI. I used to own a Pass preamp and amp… and found the Audio Research preamp and Pass amp to be the preferable combination. The ARC has a better midrange bloom… more natural and fleshed out. It really is ARC’s thing… preamps. 

@twoleftears

in my 17x20 room, i have a listening triangle roughly 11 ft equilateral, i don’t listen real loud, rarely exceed mid 80’s db peak loudness

in that context, with my mon 40’s all pass amps drove the speakers very satisfying for my listening... bass control is also excellent... i had an f6 for a time, felt that one was maybe just a touch loose gripping the woofers... my f5 is modded with extra power supply capacity (bear in mind the f5/f6 are push pull amps, not single ended as most lower powered fw amps are) so that one does fine too, xa25 xa30.5 and up all sound effortless

parenthetically, i would say my favorite for driving the mon 40’s is the linear tube audio zotl40 reference, with a pair of rel subs augmenting the deep bass crossed over very low.... that is a hella sweet combo... clarity, purity, vast spaciousness, excellent impact and of course, the midrange magic in spades...

hope that helps

Great discussion everyone. Really appreciate all the feedback and lively back and forth. 

@liquidsound you raise a great question. Being that I live in an apartment I can't really play too loudly. In fact one of the reasons I am looking to upgrade aside from a general improvement is that I find I need to turn the Sphinx up considerably before there is any weight and dynamics to the music so I am hoping to achieve a fuller sound at lower volumes.

@audphile1 I am glad you brought up the Audio Research LS-25 and Ref1 preamps in combo with the pass amp. Although I am not ready to purchase a new pre yet, I have started to look around and aside from the obvious pairing with an XP-12 I was gravitating towards the AR Ref 3. I also read some really thought provoking reviews of Shindo Labs pre amps but those might be just out of my reach price-wise and difficult to find as well. 

I’ve heard the first watt, it’s an amazing amp, the x25 is on onother league, musically dynamic.

@jjss49 Thanks !  As you've said, Nelsons' First-Watt "kitchen-table" amplifiers were designed for sounding terrific from the first-watt in mind.  The reliability also of the Pass-Labs and First-Watt electronics is well-known.  Nelson is also one designer who is very willing to share design information and I've e-mailed him questions about my amps on several occasions.  He's always gotten back to me and rather quickly, considering he must be a pretty busy man.  I love the minimalist approach to the First-Watt series and the sound of very few active components "singing" through a fairly efficient speaker can be captivating.  It was that way with the SIT-2 and my Volti Vittora's.and even my Living-Voice OBX-RW's. The Vittora's are long-gone as there was no room for them in our retirement cottages' small listening space, however the 106-db single driver speakers are coming soon ! Happy listening !

@jjss49 What's the lowest-powered Pass you've used to drive (successfully) a Harbeth 40.x?

i think @liquidsound ’s post highlights a very important point

and that is that amps of certain power levels do better or worse within some range in their power band -- for instance, using high efficiency speakers with paper cone drivers etc, very sensitive to that first watt, fractions of the first watt they ever get from the amp (btw - that’s the reasoning behind the choice of name, for those that didn’t realize...)

versus something like a modern x250.8 - designed to deliver 250w into 8, 500w into 4... amps like that operate in their sonic sweet spot when they are doing some real work, and they are at their best, they show the strengths intended by the designer when they are delivering some serious current, applying their high damping factor on woofers that need it, and so on.... you get my drift...

so given the wide range of amps offered by pass, from the (relative) fleawatt fw’s to the mega x series amps, one still needs to think carefully about speaker/room matching -- that is the key to sonic happiness

all the above said, it is also important to note that the smaller xa series amps, in my opinion, give somewhat the best of both worlds.... they are rated very conservatively at 25-30 wpc but can actually deliver well over 100 wpc on transients....

ANY  of the newer Pass Labs amps are better than ANY of his old amps.  I live 30mins from the factory.  He told me himself!

I've owned the 30.8 amp and it is a terrific powerful amplifier, despite its 30wpc/8-ohm rating.  I also own a First-Watt SIT-2 and F8, both of which are terrific amps and with the right efficient speakers have taken my listening another level higher in terms of micro-detail and sound stage.  My speakers presently are Living-Voice OBX-RW's (94-db 6.-ohms nominal) and all of the above amplifiers drive them well.  The 30.8 was plenty of power for my L-V speakers as even with high levels of listening, it never seemed strained or to run out of power.  And for moderate to loud listening, the First-Watt amps above also work well.  With your 90-db Gibbons, I suggest that if you like to listen moderately to loudly, you consider the 30.8 over the First-Watt amps.  You should consider headroom and crest factor in your listening and based on your speaker efficiency, choose an amp that will not be taxed at louder volumes.  Remember that at your listening position, your SPL may be down ~7-db, and you definitely want ~6db or more for headroom on peak music.  In my experience with my L-V speakers, the 30.8 came really close to both the First-Watt SIT-2 and F8 in terms of micro-detail other areas important to my listening, however I sold the 30.8 since I really didn't need it with my soon to have new 106-db 16-ohm single-driver speakers.  Good luck in your quest for a new amplifier to power your Gibbons !   

@4krowme I see I got my point across now. Enjoy!

audphile1,

  What is your point now? Just drop it. Move on. Grow up.

i have had the fw f5 and f6 as well as the pass models i mentioned earlier (currently have the int150, xa30.5 and a modded f5 in my collection of amps)

nelson pass has been interviewed many times, these vids are on youtube, he speaks at length to steve guttenberg and others about how each gen of pass amps, different generations of them, and different fw amps are all his playing with available components (especially various transistors, some no longer available) in various ’less is more’ circuits to produce amps of different capability levels and with varying sonic traits... he is very articulate about how different types of distortion leads us to hear certain attributes in the music

there is also a terrific thread on one of the other forums where he directly participates, and he speaks about his take on how various first watt amps sound different within their respective power envelopes...

these interviews are worth watching, easily found on youtube with a basic search, as is that excellent discussion thread where you hear the sound of various of his described by the man himself

Agreed that the F6 is a different model than the XA30 but I disagree about the relevance of who builds it. When the important parts and design are identical I would expect the resulting performance to be too.

It’s really amazing that a designer of that caliber would contribute so much to the DIY community. Pass’ love and passion is what drives him and that’s why Pass Labs have been producing such fine audio equipment and have one of, if not the best, customer service in the industry. 
 

But this is a thread where a question was raised about vintage Threshold vs. modern Pass Labs XA30.8.
Comparing Pass kits built by a DIYer to commercially produced amplifiers from other manufacturers is misleading and irrelevant to this discussion. It also won’t help the OP or anyone reading this thread now or in the future. 

I have not heard the bigger commercial Pass amps but I just changed over for the season from my Rogue Sphinx v2 to my DIY Pass F6. Despite their very different topologies,Class D with tubes, Class A, they have more in common than different. Mainly I would say the F6 throws a bigger stage and does reveal some more texture and detail. But both are great driving my KEF LS50s supplemented by a trio fo Syzygy subs.

I would consider the change to Pass just that, a change not necessarily an upgrade. But then I don't look at hifi as a competition. Like Nelson P often says, it is just entertainment. It is supposed to be fun.

Audiogon is a little strange in that things here so often get heated, like this is some kind of contest to see who has the best system. Not my view. There are many things to appreciate in many, many systems. My rule is never overstretch your budget because there is fun to be had at all price levels. Building is a lot of fun, better than just spending money. Check out the DIY store if you are into Nelson Pass. An ampcamp amp is a fine little piece of class a equipment within the capabilities of almost anybody who has the will and the time to build one...and you will also encounter a very nice on-line community that seldom argues and always helps.

@jjss49 👍

I’ve tried this approach…it was a waste of time.

Much appreciated. I will look into these.

here are some very informative threads that i have personally found helpful in the past

https://forum.audiogon.com/discussions/pass-labs-amp-s-what-is-the-best-pass-amp-sound-for-you-from-past-10-y

https://forum.audiogon.com/discussions/are-pass-labs-amps-probably-the-best-ever-you-can-buy

https://forum.audiogon.com/discussions/comparing-the-pass-labs-xa30-5-to-the-xa-30-8/post?highlight=xa30.8%2Bvs&postid=1298467#1298467

https://forum.audiogon.com/discussions/which-amp-would-you-choose-and-why-pass-labs-xa-25-or-first-watt-f8

Point taken

@4krowme

Don’t mean to derail the thread here, as I am interested in other peoples’ experience with the big NP amps.

i have to say, reading your entries on this thread it seems you are doing just that

you have owned pass kits and really old pass stuff, you don’t have experience with modern pass/fw gear, you say you are interested in other’s experiences with big pass amps

given that, it would make sense that you should perhaps say less and read more? this thread and numerous other threads comparing modern pass amps exist on this forum. with many many happy users reporting and discussing their experiences... just seek and you will easily find...

Agreed with @lucky_doggg7 - you unleash full potential when you pair a pass amp with a pass preamp. When I bought my XA30.8 I was driving it initially with the Rogue RP-5 (previously mated with ST100). Replacing the RP-5 with Pass XP-12 took my system to another level. 
Back when I had my X250.5 I used Audio Research LS-25 and Ref1 preamps with it. I recall it sounded really nice albeit having a slightly higher noise floor than the solid state combo I’m running now. 

 There is something to be said of Nelson Pass as a person. He reminds me of the Grateful Dead, who allowed themselves to be recorded by anyone during their concerts. That is remarkable by any standard. In the same way, he shares his knowledge of audio design and actually encourages it at Amp Camp and such. 

 When building his B1K preamp, which uses a DHT (SP1), you just can't ignore the great sound in spite of the fact that the SP1 tube is by no means the last statement in tubes. I have actually built other one designers' concept of this tube for a preamp, and guess what? Doesn't sound as good, period. I believe it is because Nelson uses matched transistors instead of an integrated circuit. Anyway, the beauty of kits is that you have more control over what you prefer. 

 Maybe this thinking translates to consumer products as well?

Don't mean to derail the thread here, as I am interested in other peoples' experience with the big NP amps.

I don't have experience of the Gibbon but have experience of the O96 with Passlabs amps. The .8 series are superb power amps. As per a previous poster, I would certainly look at selling the Rogue in favour of an XP12 pre. That is a very nice sounding pre / power amplifier combination to drive highish sensitivity speakers.

>>>gfys now??? You should run for office.

   My observations are based on actually owning multiple products designed by Pass. Most of them I liked, but also most of them could have had better build quality inside.  

  I have seen people like you too. Easily offended by any other perspective. So then the first response is a passive aggressive comment, followed by a vulgar shoot from the hip type remark. 

When Nelson Pass started Pass Labs, and left Threshold, his first amps were the Aleph Series of amps.  In my wanderings, I've had the good fortune to own a Aleph 5 (60 wpc Class A), then Aleph 2 monoblocks (100 wpc Class A), then finally the keepers, Aleph 1.2 monoblocks (200 sweet wpc Class A); these Aleph 1.2s are real room heaters.  Back in the day, I tried a series of Stereophile Class A preamps and they sound from okay to meh.  From what I remember, I had a Adcom GFP 750, a Sonic Frontiers Line 2 with outboard power supply; I even rolled different 6922 tubes looking for that thing that I was hoping to find.  Finally, I had enough scratch to buy Nelson Pass's new series of "X" preamps, which was the 3 box X0.2.  OH MY!  The total synergy of the X preamp with the Aleph 1.2 was something to behold.  That beautiful midrange bloom that everyone talks about from the Aleph series of amps came out to play; that lit from within detail where the inside and shape of wooden instruments could be heard.  The transient of a harp string or guitar prick - the onset of the note proper, followed by the trailing note.  Depth, width, hearing individual instruments in a 3D space.  It was all there.  This equipment was mated up to Von Schweikert VR-6 speakers, which are very fast.  The Aleph amps tamed that beast, and the detail from that Focal tweeter and front firing two 4 inch mids just all fell in synch. 

I then moved and started second system with Pass gear.  The pre is the 3 box XP-30; amps were X60.5s and my speakers with Focal Mezzo Utopias, which is all a splendid grouping.  This newer equipment smokes my very musical Aleph for detail, transient snap, greater 3D picture of instruments in a field, greater height, and that individual sound and the very specific dimensional shape of a note as it bounces in a venue when it is picked up by sound engineer's microphones is borne out.  Again, that midrange bloom, and lit from within sound that somewhat honey coats the music is very enticing to my ears.  Now, that is not everyone's taste; I like gear that errs on the side of warmth.  Presentation that is threadbare in the midrange or has that laid back presentation, ehh, while not to my liking, it is not the end of the world.  New Pass has that greater overall detail, more punch, better flow, better transient snap, and also much better bass than the old Aleph amps.  Sorry for the verbose passage here.  If you get Pass amp in the X30.8 (which is a fine sounding amp), be sure to listen to it connected to a Pass XP-12/XP-22/XP-32 preamp so you will hear the magic and synergy of a Pass pre and amp playing together; you MUST do this. 

The 400a was a nice amp in its day.  I owned one for several years.  The newer Pass stuff (I've owned several) sounds much better.  Unless the 400 has been rebuilt, expect problems.  Mine was in the shop more often than not before I finally sold it.  Unless you live close to someone who will repair it, I'd stay away. Your wallet and back will appreciate it. 

@swede58 

Thanks, I’m hesitating between a Pass XP22/X260.8 or X350.8 combo or the Gryphon Diablo 300.

i don't know the size of your room, how loud you want to play your maggies

those are very powerful options you are considering... for my application they are clearly overkill

i also prefer the slightly better (to me) tone, delicacy and saturation of pass' class a amps - of course, very high power xa versions of those are also made... but they are expensive, generate a lot of heat, use alot of power...

@4krowme Hey not trying to prove anything here. Just found your comparison and comments odd and baseless. And they still are. Have a nice day. 

audphile1,

 Excellent response, thank you. Nothing is perfect, and in spite of the intent, the camera moves around too much to get a really focused look at certain things. I know, I am being picky. 

 Like I said earlier, the chassis is really impressive (especially the binding posts attached to the chassis!). I would want to build like this if I had the money. Making of such a chassis out of sight. Internally, it is interesting to see that it does remind me in some ways of my Forte' 3. Now this is a personal thing, but I never really did accept the use of ribbon cables, even though much of the idea is spot on. It is not the cable so much as the connectors. Unless they have a really good grip, intermittent problems can arise. Again, a thing with me but there are several Bourns pots in terms of quality that are available, and they are identical just looking at them. It was one of the problems in my Forte' before I rebuilt it. 

 So, since I have never owned an actual Pass Labs product (yet I have built a few of their kits), I cannot speak to the sound at all. My personal experience is that the Threshold power amp that I owned wasn't my thing, the next three Forte' products that I owned were absolutely great, and if I could, I would very much like to hear what these products actually sound like. They do have a great following. 

 Again, I do appreciate the video. 

Wow. You are right... about the chassis. I will just keep googling until someone shows the guts inside. I've seen some pretty sorrowful crap inside a beautiful chassis, but I am betting that Nelson does way better than that. 

@4krowme you had me at the Pass kit to Krell comparison. 
 

 I am not saying that any one of these products sound good or bad, but I am just as interested in the build quality as the sound. I know, a rare combination.

You clearly have internet because you posted here…so Google is your friend…or whatever search engine you prefer. 

So many years ago, I bought a Threshold power amp, and it was an 'S' series, maybe 400 model? The point that I will make here is that even back then, I was surprised to see how ancient it looked with old brown carbon resistors, thin circuit boards, and more. To me it really looked used. I mention this because in some newer equipment, I see thick circuit boards metal film resistors and the electrolytic capacitors have come a ways since the cave days. No doubt there is equipment built in the past that was great then and now, but I didn't find that to be the case in the Threshold amp that I had.

 I wish that I could speak to the more recent products designed by Mr. Pass, but the only power amp of his design that I owned and loved was a Forte' model 3 which quite the opposite inside from the Threshold. Then again it quite a few years newer so there is that. 

 The Pass products that I have seen recently have good quality in places (I am now referring to some of his kits) but not so much when it comes to the chassis. Not bad at all, but certainly not built like a Krell either. His consumer products I have not seen to get even an idea of the build quality.

 I am not saying that any one of these products sound good or bad, but I am just as interested in the build quality as the sound. I know, a rare combination.

@jjss49 

Thanks, I’m hesitating between a Pass XP22/X260.8 or X350.8 combo or the Gryphon Diablo 300.

@swede58

in my 17x20 room, maggies 4+ ft into the room, 10-11 ft listening triangle, all three amps drove the 3.7i’s just fine, never felt strained

but i don’t listen at headbanging levels, mid 80 db transients

know that the xa25 and xa30.5 have been tested to deliver 130 wpc and 190 wpc into 4 ohms respectively without clipping... the maggies are a purely resistive 4 ohm load, as such they draw current, but phase angles are completely benign, no stress on the amp in that respect unlike cone/box speakers with reactive phase angles and severe box resonances amps must often contend with

@jjss49 

Which of the Pass amps you tried could handle the Maggie 3.7’s?

i have had the xa25 along with an int150 (x150.5 with pre front end) and also xa30.5 - have bought the xa25, sold it, bought it back, sold it again through speaker evolutions...

all three are truly excellent but of course, they sound different, do different things well

xa30.5 sweetest of the three in the treble and upper mids, most tube like, if you will -- with excellent tonal density and very good bass control, and ever so slightly softened transients

xa25 is less sweet, more ’straight wire with gain’ in the treble, but still tonally dense, and slightly better bass control, sounds faster more like an x series, than xa

int150/x150.5 similar to the xa25 in treble extension, tonally a bit less dense/saturated, tremendous bass impact and control, mids slightly leaner (just slightly), and of course, a notch greater headroom

i think the differences above capture the essence between the xa25 (which i consider a middle ground between x and xa amps for reasons enumerated above), and what would be consider typical xa vs x series amp’s sound

basis for my commentary is driving the following -- spendor sp100 r2, harbeth mon 40.3/40.2, magnepan 1.7i/3.7i and most recently, laufer technik notes

XA 25 is a very pleasant sound with good bass control. Xa30.8 is double the weight of the XA25! It’s very rare to hear someone say they they don’t like the sound. Tastes do vary.

I think the first watt stuff will lack reserve power.  If you don't listen very loud probably OK with excellent sound.

I saw a completely rebuilt Threshold a while back.  $2500.  Demo pass units will start around 4000.

Coda S5.5 could be strong alternative in class A contenders. Threshold is gone, and while Nelson Pass, founder of Threshold, has been producing amplifiers under his own name for some years now, other former Threshold employees are also designing and manufacturing power amps. Their company is Coda Technologies, and their amplifiers are completely up to date in terms of parts quality and circuit design. 

Threshold made fabulous gear, but a 400A would be >40 years old now.  If it hasn't been updated, you should definitely include the cost of having it gone through, and at the very least having the power supply & other electrolytic caps replaced.

It will still be less expensive than a Pass or First Watt amp, but you get great sound at a discount.  If you have the budget, Pass is still going to be your safest bet, though. 

Nelson has always been clear that he knows we all have different sound priorities.  He started FW as a venue to experiment with different output devices, and optimize their unique sound signatures.  That's why FW doesn't have the traditional pricing hierarchy found at most amp makers.  While a fascinating concept, it puts more of an onus on the buyer to choose their own favorite "sound".

I have slightly more sensitive speakers and when I went looking for my Pass amp, I was between the XA30 and the XA25. Those who had tried both said there was something especially magical about the XA25. (Of course there's always a debate!) I was concerned about the power level but in all honesty, the XA25 is NOT a 25 watt amp and has plenty of power given the very nice ohm-load your speaker presents. Harley Lovegrove of Pearl Acoustics agrees, here.

Then there's this 6moons review that quotes Terry London: "Wanted to share that I just got through submitting my writeup on the Pass Labs XA25. I believe that this might be the best amplifier Nelson and his crew have yet created/built. I own a pair of XA-60.8, a FirstWatt SIT 2 and have had in my system an XA30.8. The XA25 does color, tonality, spatial qualities, bass control and overall macrodynamics different and better for my taste than these other wonderful amplifiers. I still cannot believe that I'm not listening to a great tube SET were it not for how quiet, quick and dynamic the XA25 presents the music."

Your speakers sound easy enough to drive for the XA 25 -- as Stereophile put it, " Its sensitivity is specified as 90dB/2.83V/m—rather high for a small monitor speaker. The impedance is given as 8 ohms—a "very flat" 8 ohms, according to John, and never dropping below 7.4 ohms."

@wturkey  you realize there are two sides to every schwartz ....