What are the weak points of Pass amps and pre-amps ?


Though there are perhaps better transistor amps, but Pass seems to be an excellent choice for many.
What is your experience with them, if you could elaborate ? Integrateds as well.
inna
I own the XP-20, best preamp I’ve owned.  I don’t have an extensive list of A/B’s to other preamps, so I wouldn’t be able to comment on what it lacks.  It sounds better than the handful of McIntosh preamps I’ve owned and PS Audio BHK pre that I demoed for a bit.  

It’s a very revealing pre.  You hear a lot of detail at low volume or high.  In my system, everything sounds authentic with it.  I’ve pulled it out and ran others, but with the XP, it just sounds organic, balanced in the high/mid/low regions and, well, as I already said, authentic. 
Had Pass 350.8 wonderful stage,bass,depth,imaging and powerful full bass didn't see any weak points.
Price. Value.

I have repeatedly been told they are very refined amps. Never heard a pair that made me wamt to take out a mortgage for them.


I have the XP12 and 250.8.

Really like them, the weakness is that because like most of us I like to try new things... but these are the first combo that I've been afraid to sell off and try something else!

So, suppose tempering the fun of research and upgraditis could be a weakness.

I feel the XP12 is really neutral.  I don't think the 250.8 is dead neutral, but it just sounds good with every speaker I've tried with it.
I made an extensive list of all the weak points and shortcomings of Pass pre-amps and amps. Here it is.....this is everything I could come up with.....




/insert blank page





By "weak points" I meant more their weaker points compared to their strengths, not something that they do wrong.
I don't believe in absolute neutrality, and I most definitely don't want sterile sound.
ebm. you now have Audia Flight amps, how do they compare, what are the differences ?
Pass Labs is not the uppermost high end, as I understand, speaking of a wish to have them at any cost. As for value, they in fact do appear to be an excellent value. Not engaging enough ? Not much to write home about ? Just excellent amps ?

IMHO:

 expensive,

 heavy,

 inefficient,

 large,

not ideally suited to sub 4 Ohm loads,

 added cost, light distracting, extra parts meters, (which again IMHO) I don't have confidence in the accuracy of,

 confusing power specs,

leaning on the warm side of neutral,

Not at the top, but certainly on my shortlist of favorite amps.


So if I had to absolutely nitpick...

250.8 - runs warm, no question it warms my room up.  Not horribly so, but it does.

May not be the absolute best at top end resolution and sparkle.

I've heard Class D amps that are a bit punchier in the bass, a shade tighter.

You can get a similar sounding amp with similar specs (BAT) for a bit less money though the specs may differ a bit.

Bias meter more for show, though it's nice to have an idea when it might be moving out of Class A operation.  Plus it looks cool.
I have never heard a Pass amp.  But I wish someone would come up with some serious weak points so I won't feel I absolutely have to have a XA25.
A friend owned Pass gear. Sounded great with his system. He passed away; so much I miss him and his love for audio.
Celander, sorry to hear about your friend.
They are not expensive compared to Gryphon, FM Acoustics and other Swiss brands, or even some Japanese, I guess.
Yeah, those lights would bother me, that's BS. Big and heavy, all good amps are big and heavy and inefficient.
Not enough top end resolution and energy - now this is a weaker point.
Being on a slightly warm side of neutral is a strong point for me. Redgum amp that I have is exactly that, good balance.

buy used Pass amp and pre and they will hold their value incredibly well, so not so expensive in long run...I owm X250.8 and XP-22...actually ended up spending very little on the used X250.5 and XP-20 that I traded in after owning 4/5 years...
Does everyone prefer class A Pass amps overall ? Both current and older.
I prefer the X series, though have not heard the top of the line XA...my dealer said many prefer the X to the XA at given price point...
That's unexpected. Could you say more why you prefer X series ?
When I told dealer I liked clean clear accurate dynamic sound he said try the X250,8. And that was my favorite over similar price XA and X350.8
What some hear as sweet others hear as veiled
Unsound dude its not nice to bad rap PASS.However I'm sure that what you have is much better.(NOT)
Unsound dude its not nice to bad rap PASS

So we should say everything is either great or not say anything at all?  Why should he not state his opinion?  Isn't that the whole point of the thread?  The way you think is one of the biggest things wrong with high end audio.
ebm used to have Pass so it has to be great, no room for anything negative no matter how little.
Pass makes some very good products however all of the points Unsound makes are very valid Pass’s gear tends to be big, heavy and runs hot.

In our tests we have compared a set of the big Pass X 160 we think a $30k Monoblocks to a set of Chord Monoblocks and the Chords were better.overall amplifiers with a client driving a pair of Martin Logan CLX

Tejay just compared a $6,200 Coda .8 which is a 150 watt Class A amplifier to a pair of $14k set of Pass Labs mono amps and TJ liked the Coda as much as the twice the price XA 60.8. and thouught the Coda was similar to the Pass but less colored.

We had a client compare a Pass Int 250 to a T+A 2500R both are $12k integrated and the T+A was prefered over the Pass as the T+A was faster, cleaner, and had more punch yet was lighter and ran much cooler.

Lastly another poster here switched from a Pass Labs preamp and amplifier to a T+A HV 3100 integrated as well with the same results reported.

What does this tell you? Pass makes good stuff but they do seem to have lost their edge compared to some of these other companies.

So perhaps Jetter you may want to consider the Coda .8 which gives you 150 watts Class A vs the Pass Labs xa 25 which gives you 25 watts of Class A power before switching to Class A/B so you are getting 3 times the rated Class A power for only $1,200.00 more and you get a totally cool set of meters.

Dave and Troy
Audio Doctor NJ T+A and Coda Dealers


I upgraded from a Bel Canto Ref500s to a Pass XA30.8 a few years ago. Although the Bel Canto was not bad, the Pass was a dramatic improvement. I tried a Devialet around the same time and it wasn't for me. As amazing as the Pass amp was, the downside for me was that it heated up the room so much that it became uncomfortably stuffy. This is likely much more of an issue because I have a small room (10'x12'). It might not be an issue for a larger room like a living room. I thought that I might have to return it because the stuffiness was too much, but instead I got the HVAC modified by getting a return vent installed in the room :) I liked the sound that much!
Knew it was just a matter of time before Troy showed up and told us why his products are superior to Pass.

Predictable and amateur. The OP specifically asked about Pass, not comparisons to others, said there may be better amps, but specifically asked about Pass, then a few posts later asked about weaknesses compared to strengths. He did not ask for someone to come in here and compare Pass to other brands, or sell them on something. But you just can’t resist.

That said...

For every dealer that has had someone go from Pass to Brand X... someone else has gone from Brand X to Pass labs, or from Brand X... to Brand Y, you know, system synergy and all.

OP, I could care less what you buy. What is interesting is how depending on the thread Troy will reference Pass. You know... the "new" Krell now sounds more pass labs like...

Pass hasn’t lost any edge. As Troy likes to do... just look for the reviews out there that compare the 250.5 to the 250.8... and the XP10 to the XP12, if you want to read reviews.

I like TeeJay, but if an amp sounds similar, yet is "less colored" - then it really doesn’t sound similar does it?

Personally I do like Coda, and Doug at Coda. But for me, a weakness of that amp is that MY PERSONAL OPINION IS - that amp looks terrible. (I liked their old look better).

Overall of all the "pro" reviews out there.... find me more than 10% that are bad about any product.

Lots of good amps, just depends on what you are looking for. Pass is one of many really good brands out there.

They do run a little heavy, and run warm. No question about that, per your original question.
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Back to an earlier comment.

With Pass (250.8 in my case).  When I say they might not be the ultimate in top end resolution, I will clarify by saying this.  You don't lose any information, all the notes are there etc.  But say something like cymbals won't be as forward in the mix with a Pass labs amp as other brands in my experience.  

This may be a weakness or a strength depending on your speakers and what you like.  I like a big full midrange and do not want cymbals too far forward in the mix, I listen a bit loud and always tend to have cymbals distract me.  

Some people listen more at moderate levels and want every last bit of detail and sparkle.  Pass would do that, but maybe something else might be more enjoyable for that listener.
Dep you are so more advanced now aren’t you?

If TJ is prefering a Coda to a Pass Labs amplifier and stating that a $6,200.00 Coda is sounding as good as a $14k pair of Pass Labs mono amplifiers and Doug Dale worked with and was one of the lead engineers at Threshold don’t you think that is a valid point, not to mention being able to offer a product which is 3 times as powerful for only a bit more money?

As per ugly, meters are cool. Look how many Mcintosh amplfiers have been sold and they got meters if an amplifier has meters and sounds better and is more powerful do you think most people would care if the amplifier has or doens’’t have meters?

There are others are also agreeing that Pass is getting surpassed by T+A Does that mean Pass isn’t good, not it is not, there are however cooler running, lighter weight more practical power amplifiers that people should consider when making their choices.

Do you think that if jetter or anyone else got turned on to Coda by reading these posts and then loved that product would they be happy. or not.

Do you not think that we could have been Pass dealers? We were looking at the line long before we picked up T+A and Coda, we picked up T+A because it is among the very best products in the world with far more advanced design and construction then what Pass can provide for similar pricing and Coda is very similar to Pass Labs’ designs for considerably less money and is one of the best small companies out there in term of sheer sound quality for the dollar with fantastic build quality.

As others here have mentioned the heat, size and weight of a Pass Labs product means they are not beloved by everyone.

A forum should be open to all that are looking to exchange ideas and be open to looking at and listening to other products that may prove to be interesting, and who knows some people might actually find that they too find some of these alternatives to sound really good as well, and perhaps either offer more for the money or more performance, or both.

Dave and Troy
Audio Doctor NJ
I would not run them 24/7 and where I live it is often chilly except in summer so I would just turn the oil heater off and have the amps do the heating. In summer, yeah, but the equipment is in a living room with windows, some extra heat would not be a problem.Electrical bills..not sure, maybe $20-$30 per month more, I could live with that.
I also like big full sound, not forward not laid back, with deep and layered soundstage and three dimensional notes and silence moments. I can sacrifice some details and high frequency excellence. Besides, I don't tolerate high frequencies distortion, and there is so much of it in many recordings.

audiotroy, please, enough of your participation, we get all your points even before you posted. If you want to advertise yourself in this thread - pay us, cost - $1 per letter. If you disagree - get the f. out.
As usual Troy, you hijacked a thread to push your wares.

I like meters also.  Just think that new coda looks like tic tac toe board.  I’m sure it sounds great. I’ve stated that elsewhere. 

Hell I’ve talked to Doug, he’s a good guy.  He thinks meters are useless, but knows the market likes them.  

I answered the OPs original question.  You hijacked a thread again.

Yes, T+A and Coda make nice products.  I’ve owned Coda and demoed T+A.

I mentioned the heat and weight, as I was answering the question. 

So, so far no real weak points, just a few minor weaker points.
But no-one described Pass Class A and Class AB differences in details yet. Anyway, one can get Pass pre/power amps used for $5k-$6k for both. Pretty good.
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Inna, currently I have pass int-250 (again). Before that I had many integrated including bryston, plinius hiato, gamut 150le, pass int-60, gryphon diablo 300, luxman 509x. I had to sell gryphon diablo for financial reasons. In my system with my speakers (Sonus Faber Amati tradition) gryphon and pass-int-250 were the best. Initially I though pass is lacking dynamics, until I found cables and power conditioner that made it sound more dynamic and more explosive. The top end also became great - again proper speaker cables needed to extract everything that pass can provide. Gryphon 300 was better with dynamic swings and articulation but not much. Pass has bigger 3d sounstage. Weekness - some air between players is not as good as dagostino and gryphon.  Read Audiodorm review on pass int-250 were they give 92 points to this integrated and prefer it over accuphase 650 and luxman 509x. There is another reason I decided to get pass again - service and US made product.
Denon1, I remember that you got Gryphon Diablo. Yes, I would not expect Pass to match Gryphon in dynamics, resolution and instrument separation. And of course at this level cables and power cords are even more important that at lower levels.
Big 3D soundstage is great, this is very important to me, especially with certain kinds of music.
I owned the Pass XA30.5 and it put out very little heat into the room going 24/7.

I now have a pair of XA60.5 going 24/7, and do not notice a rise in room temp. I have the amps on 2 Inch maple boards. Electric bill is up about $30 per mo. when on 24/7.

Pass Labs gives me SOTA sound quality! Could not ask for more.

I like a dead quiet room, so I shut off heat or A/C when listening.
I'm with Jetter as someone hooked on tubes who wishes people would stop raving about the XA25...please stop...I don't want to get rid of my single ended tube amp...but the existence of the XA25 is taunting me...I'd appreciate it if somebody would pan that thing so I could stop wanting one.
Sorry, @wolf_garcia, but the XA25 is the best amp I've used in my system. I've used: CJ MF2550SE, ET250S, Musical Fidelity SS.

What I love about the XA25 is that I get >wonderful midrange from the CJs with most of the bass slam of the MF SS. The XA25 has the best soundstage of all from my Sophia 3s.

But no, no real downside to the XA25 except that it doesn't have the bass authority that I've heard from other amps.

Well, another downside is that my other amps only get used in my office system or are in the closet waiting for adoption to a happy home.
Well you asked so here is my opinion. I owned for quite a while the Pass X350.5 amp and the XP-10 preamp.

The XP-10 preamp to me was average. The step up from it was the XP-20 which has 2 separate chassis, I never heard this unit but I didn't like having to use extra rack space for the units.

I compared directly the Pass X-350.5 to the newer XP-350.8. I just did not like the newer X350.8. To me it sounded much more closed in and had less treble presentation than the older 350.5. Caution either chassis gets very hot! 

Eventually, I tried an Atmosphere M-60 3.3 and sold the Pass. Today, I own the Bob Carver Raven 350 tube amps.

Each step improved my audio enjoyment as I moved away from Pass.

ozzy
Jetter, I own an XA25. It’s cheap in that it punchers wY over the specs and is brilliant.  I also own their pre XP-22.  Have had XP10 as well. Very good equipment.  There is nothing bad here.  I came from mostly Reference level CJ TUBE equipment.  
Well thanks medwardo and jahatl, you have both convinced me that the XA25 is not worth the investment.  Well that's totally not true, and in time I feel I will be purchasing one, but not for a little while yet.  Enjoy the Pass, and its all fun.  
George
Since you are interested in the difference between XA and X, call Kent English at Pass.  5308785350

I have the XP-12 which can turn on the XA60.8. The Ayre preamp couldn't. I needed that functionality.

Wayne, the designer of the preamps told me that the XP-10 cannot turn on the XA60.8. 

The combo is good to my untrained ears.
 If you are worried about the price of Pass amps and happen to have efficient speakers, try the First Watt line. Wonderful amps that won't break your bank.
I have not heard all of Pass Labs amps, but from recollection of a few I did owned it’s good but not great.
I had the X350, X350.5, XA100.5, XA160.5, XA160.8, compares to MSB M202, M203, Lamm M2.2 and ARC REF250 and even Bryston 28B3, one would wonders what the hypes was all about.
As you can see, I did fall for the hypes with owning 5 different Pass models.
Not bashing on Pass, I’m sure the XS is a must for class A enthusiast, including myself.

@medwardo - I have the X250.5 driving my sophia 3s and have the itch to move to an all class A. Even though the X250.5 offers the first 25W in class A. I spoke with Pass and they didnt think highly of a move from the 250.5 to the XA30/60.5. They did mention that a move to XA100.5 will be very rewarding and worth the move. Is your XA25 able to drive the Sophias well? They are known to dip well below 2 ohms at low frequencies.
pistha, while you were talking with Pass Labs did you ask them their opinion regarding the XA25 driving your Sophias? I ask because I believe my speakers also dip rather low although I only know their nominal impedence.
A few years ago I bought a pre-owned Pass INT-150.   I replaced a Wyred4sound 4 channel amplifier, because I no longer needed to bi-amp.  Talk about going from apples to oranges... The Pass was kind of an impulse buy.  I did not compare to anything else at the time.  I can't really come up with any weak points other than that yes, they do run very warm.  That is intentional though.  I don't plan on changing unless some other system change forces me to.  I can envision a scenario where an integrated would not be appropriate, but for my system now, I prefer the convenience and the sound synergy of the Pass integrated.
Expensive, Big,run hot also cost a lot to run, forget Solid State, have a listen to a Nord Acoustic mk11 class D with the REV D upgrades, you can choose various OP-AMPS depending on ones taste or system, you can buy all the various OP-AMPS and find which ones suite your taste its called OP-AMP rolling,

Phone Colin he sells direct worldwide and prices are very reasonable, my Nord One UP SE NC500MB mk11 costs approx £2000 and sounds amazing no faults at all, its xlr only, 

Then find yourself a good pre-amp with the money you saved I recommend Townshend Audio  Allegri + no need for expensive power cord or conditioner, no mains noise, its single ended only, i use Cardas Clear female rca - male xlr the combo sounds incredible for £4500 

Check out the review of Allegri + in Positive Feedback and Nord Acoustic stereo amplifier in HIFI PIG and Six Moons 
I do not know Troy and have never shopped in his store. I enjoy his posts. While he certainly has some motive to promote the brands he sells, his thorough and knowledgeable insights allow me to learn about large, heavy and expensive gear w/o having to buy (and sell) everything out there. I purchase from (the few remaining) brick and mortar stores locally as well as from retailers and private sellers on A-Gon. I do not post very often these days, but do read many of the A-Gon threads. At 61, & with a bad heart, my audio addiction has become more difficult to feed. I no longer find it at all easy to transport, unbox, set-up, re-box and ship large and heavy equipment. Thanks to Troy and others who post and provide insight to the fine Audio gear that is becoming more and more difficult to hear in stores and audition at home.


I have owned different Pass power amps and mono amps. I had contact with Desmond Harrington (President of Pass Labs) for a long time. I also owned the XP-20. It is a good preamp, but not a stunning one.

When you judge Pass Labs on all the aspects/properties of sound. It will become clear that they lack realism in the individual focus of voices and instruments. When you listen to voices and instruments in real they are very small and direct. The Pass Labs preamp and power amp are not able to create the intimate focus as in real.

Desmond told me that the 0.8 series make voices and instruments smaller and more palpable. But it is still not among the best. In my world, it is only about the best possible. The rest is 100% useless in my world.

Voices and instruments are not only very small and direct. In real you can even hear the shape of a voice and instrument. I call it a High End ++ property. When you judge Pass Labs on this, it shows that it cannot reveal this part.

When I was in Munich at the High-End show in 2015, only one system of over 700.000 euro who was able to reveal a 3D shape of voices and instruments. The problem in audio is that most people who work in this world or see it as their hobby know very little about sound and music. Even most manufacturers have very limited knowledge and insight in sound in general.

When I talk with them about the acoustics, electro-smog, high-frequency noise and magnetism they still know very little. It becomes clear why so many audio brands and products are still sound so different than music sounds in real.

You need to understand all the aspects that influence both sound and stage. Sound is very complex and can only be understood and guided when you understand the influence of all these aspects. In all other situations, you still do audio by trial&error. This will always be audio without any real foundation. It can only create audio systems that miss essential parts of sound with also many flaws.