Pass Labs X250

[blackraven]

Well I arrived home last night from Vegas and hooked up my Pass amp that arrived that day before. Initially I had a problem with my preamp which has been rectified today. After a few hours of listening, I have finally reached audio nirvana. I am astounded at how good this amp sounds. The amp is extremely musical and dynamic. The music is more palpable and emotional. It sounds more real. The amp seems to have no sonic character of its own. It simply gets out of the way. The level of clarity and detail is much better than my A21. The back ground is completely black. The is no grain, edginess, harshness or fatigue. Bass is tight, controlled and deep, more so than my A21. The amp has this effortlessness about it. Music played at low volume sounds the same at higher volumes which is saying a lot considering my speakers are Magnepan 1.6's which tend to sound their best at moderate to loud volumes. The sound stage is huge, the amp has the ability to take compressed recordings and open them up. The level of transparency is fantastic and the music has a 3D sound. There is much improved spacing among instruments and it seems like I can pick them out of the air. The overall sound is very liquid and smooth. Before I bought this amp, I was thinking about buying a pair of Magnepan 3.6's or 3.7's. But the 1.6's sound great with this amp, I now see no need to upgrade the speakers.

If I have to list the con's to this amp, they would be that it gets hot while my A21 almost never got warm. After 2 hours of listening it warmed up the 17x17x9 room. The X250 also has a power meter on the front and at the top of the meter is a bright blue LED that is irritating when I turn the lights out and listen. I took care of this by placing a small piece of blue painters tape directly over it to diffuse it. The amp also weighs in at 100lbs and requires 2 people to move. By comparison, my A21 was 60lbs. As far as sound is concerned, the midrange could have a little more weight or lushness to it.

By the way, if any one is interested in purchasing a used X250, let me know. There is a guy selling one for about $2650. He wants to move up the line to an X350.

Anyone interested in buying a Parasound A21 for $1300, give me a buzz.

[harley .guy07]

that is exactly how I was the first time I hooked up my X150.5 and listened to it. I am glad you are happy with your new amp and I was kind of excited to hear how it compared to the A21 since the Parasound gets high reviews from all the publications. I guess in its price class it is good but the Pass amps are in their own league in my opinion.

[blackraven]

Thanks! The A21 does a lot of things well and at its price point it is hard to beat. But it is way out classed by the Pass. I can't see any reason to buy another amp unless I win the lottery. By the way, I swapped in a pair of tubes that have a fuller mid range and it took care of the mids needing some added fullness. Now I have nothing to complain about the amp till summer comes.

[harley .guy07]

they are very expensive space heaters. But they are well worth it sonically. By the way when you are running your amp at listening volume where does your needle seem to rest at. I just wonder because running my Dynaudio's the needle runs at about 1/3 unless a really hard bass hits and I know that is a good thing because most likely I never leave class A mode for most of my listening which is one of the reasons these amps sound so full of emotion in the first place.

[blackraven]

My needle runs at about 2/3's between the left hash mark and center. However, when I play bass heavy dynamic music at moderate volumes, the needle crosses over to the right of center and moves around quite a bit. I love this amp so much, I think I am going to divorce the wife and marry the amp.

I will post some pictures of my gear next week.

[blackraven]

By the way, many thanks to Mr. P and Harley for initially turning me on to Pass Amps. I have never heard one before and took a leap of faith.

Best Regards,

Larry

[Feanor]

By the way, many thanks to Mr. P and Harley for initially turning me on to Pass Amps. I have never heard one before and took a leap of faith.

Best Regards,

Larry
Congrats on your new amp -- I'm envious.

Like I said recently, Pass Labs is the one marque in which I'd have complete confidence to acquire sound unheard.

[frenchmon]

Well well now Raven...whats the fuss all about? Oh, you got Mr. Pass in the house! Great amp isn't it? congrats my friend....glad you are having fun again...but if you want to take things up a notch or two, get some better cabling...at least do your new amp a favor and get a new Power Cord! Ask Mr P...he has a very good Power Cord in the Clarus Clemson Power Cord...best cord I have ever heard....and if you dont want to for out that kind of doe, you can always get the Triode Wire Labs cord at much cheaper prices.....try the Triodewirelabs.com 7+....I have the 10+ and its not to far behind the Clemson. I'm sure after a while you will stgart noticing some of the things I talked about in my posting.

[Feanor]

Well well now Raven...whats the fuss all about? Oh, you got Mr. Pass in the house! Great amp isn't it? congrats my friend....glad you are having fun again...but if you want to take things up a notch or two, get some better cabling...at least do your new amp a favor and get a new Power Cord! Ask Mr P...he has a very good Power Cord in the Clarus Clemson Power Cord...best cord I have ever heard....and if you dont want to for out that kind of doe, you can always get the Triode Wire Labs cord at much cheaper prices.....try the Triodewirelabs.com 7+....I have the 10+ and its not to far behind the Clemson. I'm sure after a while you will stgart noticing some of the things I talked about in my posting.
The extent to which cables make a difference depends on the combination of cable + upstream + downstream component, and there is know way to reliably predict which of the thousands of combinations that will work.

This make cable swapping the fastest method to pi$$ away your hi-fi budget with no certainty of results.

[harley .guy07]

I also believe cables make a difference and will eventually change to better cables myself but I am so happy with things the way they are after switching to the XLR cables and using my interconnects between my dac and preamp that it will be a while before I buy anything else cable wise. If anything I might upgrade power cables on my amp and also on the Quintet but other than that I think I will just enjoy and save for an upgrade in speakers. I would say let Raven enjoy his new amp for a while before trying to get him to throw down $500 on a new power cable. Just my opinion.

It is interesting to know where your amp runs with higher volumes on your Magnepans since they are notorious for needing power to be their best. I was wondering because when I upgrade speakers I am not sure which direction I am going yet. I have moved to a new house with a much bigger listening room(20X15 1/2 X 8) which is not huge but big enough to have a lot of choices with my next speakers so I am keeping up on all the otions so when the time comes I have a direction.

[Jack in Wilmington]

Well well now Raven...whats the fuss all about? Oh, you got Mr. Pass in the house! Great amp isn't it? congrats my friend....glad you are having fun again...but if you want to take things up a notch or two, get some better cabling...at least do your new amp a favor and get a new Power Cord! Ask Mr P...he has a very good Power Cord in the Clarus Clemson Power Cord...best cord I have ever heard....and if you dont want to for out that kind of doe, you can always get the Triode Wire Labs cord at much cheaper prices.....try the Triodewirelabs.com 7+....I have the 10+ and its not to far behind the Clemson. I'm sure after a while you will stgart noticing some of the things I talked about in my posting.

Hey Frenchmon, I think your spell check failed you. I believe the Clarus cable is called the Crimson, not the Clemson.

[blackraven]

Thanks guys. Right now my wife would make my life miserable if I spent more than $100 cables. I plan on buying a pair of Analysis plus interconnect cables in a couple of months. I can use another pair of IC's. I do have an after market AQ AC12 (with a ferrite for RFI) power cable that I was using with my A21 that I will give a try with the Pass. I have to think that power cables are system dependent. I have noticed no difference with the power cord. It came with my Music Hall CD player and pro reviewers said it made a noticeable difference in the sound of my MH, but I did not notice a difference with it compared to the stock power cord. I have noticed differences with some IC's, some good and some bad.

If I make any expensive move, it will be to upgrade my preamp. Van Alstine had a new tube preamp that I can swap in my current chassis for about $800. I was over at his house the other day and got a chance to listen to it and it is an improvement over mine. Or I may look for a used BAT with balanced connections. I will be doing a review of Van Alstine's 2 new tube preamps in a couple of weeks after he gets back from the RMAF.

[frenchmon]

Fenor...i have been in a few cable shoot outs.. And I can say without a doubt, cables and power cords make a difference. But some gear...especially cheaper gear can have to much of a house sound that wont pass the sonic signature as well. My Rotel was like that. It had a strong house sound. The Vincent gear is totally different. Its clear and transparent and responds to anything I use in the system.

thanks Jack for the correction.

Yeah I can understand what Harvey is saying. When I got the Vincent, I used the stock pc to run it in. After it was run in I added the PC. Now PC as with all cables are going to lean towards the warm side, be neutral, or lean to a more lively side. But what a cable should not be is grainy or not clear....a pc can be warm or bright and neutral and still be transparent. The Triode wire Labs PC is neutral. What it did was let me hear my amp...let me hear how it sounds in all its glory. It gave me better clarity and filtered out the back ground noise. Music seems to hang in the air more than before. I also heard this with the Crimson pc as well.

The A+ interconnects are a great entry level cable. I like them and I think Mr Peabody after hearing them in my system thinks they are a good bargan as well at their price point. I will be moving up the line. I did speak to the owner of A+ cables and he told me they have some new models coming out in speaker wire and I assume inter connects as well...so I will wait until he releases new stuff before I make a purchase. My offer still stands....once I get new ones, I can send you my older ones to check out. But thats if you have not purchased them as of yet.

[Feanor]

Fenor...i have been in a few cable shoot outs.. And I can say without a doubt, cables and power cords make a difference. But some gear...especially cheaper gear can have to much of a house sound that wont pass the sonic signature as well. My Rotel was like that. It had a strong house sound. The Vincent gear is totally different. Its clear and transparent and responds to anything I use in the system.

I'm just going to say that I'm NOT one of those people who say cables make no difference. I will say I have never heard any difference in normal listening -- BUT I'm not about to admit that my equipment, (including my ears), is so crappy as to be unable to differential the sounds. So call me a naysayer if you like but actually I'm just skeptical.

[harley .guy07]

I am not skeptical by no means that cables make a difference. I have proven it to myself time and time again in my own system and others that I have installed over the years but I also believe there is a limit to what a cable should cost or how much a person should spend on a cable in comparison to how much improvement it gives them in a system. a couple hundred or a few hundred dollars is about my limit. These cables out there that are $10,000 is ludicrous!! I just can't justify that to myself.

[frenchmon]

I am not skeptical by no means that cables make a difference. I have proven it to myself time and time again in my own system and others that I have installed over the years but I also believe there is a limit to what a cable should cost or how much a person should spend on a cable in comparison to how much improvement it gives them in a system. a couple hundred or a few hundred dollars is about my limit. These cables out there that are $10,000 is ludicrous!! I just can't justify that to myself.

True that!

[blackraven]

I have found that some IC's sound different but I have not found that different speaker cables and power cords have made a difference in my system.

[frenchmon]

What PC are you using now with the Pass?

[blackraven]

What PC are you using now with the Pass?

I am using the stock cord but later this week I will swap in my AudioQuest AC12 to see if there is a difference.

[Feanor]

Someone is selling an X150.5 on AudioAsylumTrader for $2700, HERE (http://www.audioasylumtrader.com/ca/listing/Amplifier-SS/Pass-Labs/X150.5/96108). That's a fair price, wish I could take advantage of it.

Same guy is also selling a Pass Labs X1 preamp, HERE (http://www.audioasylumtrader.com/ca/listing/Preamplifier-SS/Pass-Labs/X1/Full-size-power-supply-chassis/96109).

[blackraven]

There are a couple of X1's for sale on audiogon. I hope to be able to upgrade my Preamp in about 1 year.

[Feanor]

'Raven, check your PM's -- your message quote is exceeded.

[frenchmon]

I am using the stock cord but later this week I will swap in my AudioQuest AC12 to see if there is a difference.

Raven...that cord is for a component such as preamp or CDP...its a 12 gauge. For the Pass you need at least a 10 gauge to hear a real change in the amps performance. Man you can get a good 8 gauge power cord here Triodewirelabs.com

http://triodewirelabs.com/images/sevenwire.jpg

[blackraven]

Frenchmon, I will take you up on your offer about the A+ cables.

Thanks,

Larry

[frenchmon]

Ok...as soon as the new stuff comes out I will send you a pair.

[E-Stat]

I am astounded at how good this amp sounds.
I've been of that opinion since I heard Nelson Pass' first amp, the Threshold 800A back in '75.


If I have to list the con's to this amp, they would be that it gets hot while my A21 almost never got warm.
All his designs are amply biased. All one needs to do is look at the massive heat sinks found on virtually all Threshold/Pass Labs/First Watt models. My '81 Stasis also runs quite toasty. :)

[blackraven]

.

All his designs are amply biased. All one needs to do is look at the massive heat sinks found on virtually all Threshold/Pass Labs/First Watt models. My '81 Stasis also runs quite toasty. :)

Thanks E-Stat, I am slowly piecing together a high end system.


The A21 has massive heat sinks as well and plays in Class A up to 10wpc but the Pass plays in class A I believe up to 25wpc which accounts for the heat difference. I find it interesting that Parasound rates its power at 250 wpc at 8 ohms and 400 at 4 ohms at 20-20,000K while Pass rates the X250 at 1khz 250wpc at 8 ohms and 500 at 4 ohms. The A21 puts out 60 peak amps and the X250 only 20 peak amps. I found that the A21 plays a little louder before I can hear distortion. I am not putting down the Pass as it way outclasses the A21 in dynamics and sound quality. I was looking at used Classe, ML and Nuforce Model 9se amps before I found the Pass. I am not disappointed in the least. Now I need to find a new DAC and Preamp as the Pass has brought out their weaknesses.

[E-Stat]

The A21 puts out 60 peak amps and the X250 only 20 peak amps.
Puts out 60 amps? Don't think so. Read the salesy pitch again:

"Current Capacity: 60 amps peak per channel"

Let's do a little Jethro math. Rail voltage is likely between 60 and 70V. At 70V, that would be drawing over 8 kilowatts or about 65A AC from the wall. Using a 12 amp fuse and a 15 amp power cord!

They are most likely referring to the theoretical capacity of the output devices. For example, my Stasis has thirty-two 150 watt output devices capable of 4800 watts output - for an amp rated at 100 watts /channel into 8 ohms and 200 watts / channel into 4 ohms.

[blackraven]

Sorry for my lack of wording as I stand corrected.

[E-Stat]

Sorry for my lack of wording...
No problem. I looked again at the Parasound features page which verified my guess. Note this:

"16 beta-matched 15 amp, 60 MHz bipolar output transistors"

Since it requires a pair of transistors to conduct a signal, multiply 16 X 15 X 0.5 for total output and halve that again for the per channel result. That's how they got the 60 amp per channel total capacity - as stated in terms of what that many devices could deliver.

By contrast, Pass states the current output in terms of what the power supply can actually deliver. Note the wording on page 5 of the manual (https://passlabs.com/download.php?download_file=https://passlabs.com/images/uploads/manual/x250_om.pdf).

Both answers are *right*, but not comparative.

[Mr Peabody]

I would recommend a preamp with true balanced circuitry to pair with the X250. Also, think of how your amp sounds and stay open minded to a Pass preamp. I'd love to get an X1, it's supposed to be not as warm as the current models, I don't personally find my set up overly warm, the X1 is also said to be a bit more transparent. I'd be willing to bet you'd like a XP10 Larry.

Sometimes upgrading cables/cord can be as much of an improvement as upgrading a component. Cables can be expensive but depending on the improvement can be well worth the expense.

[blackraven]

I am open to a SS preamp and have looked at a couple of used X1's. I am leaning more to a Pass pre due to synergy. If it was a year from now I would have jumped on one of those X1's.

[frenchmon]

I think you are headed in the right direction, Raven with a Pass preamp. That synergy is all too important. But don't sleep on cables man as they are just as important in delivering all that synergy.

[Jack in Wilmington]

He's definitely headed in the right direction and on the right street with the x250. I mentioned the x150.5 to the wife on the way to the beach today and she didn't say no. There is one on Audiogon and it's only about 45 minutes away, but it might be too soon after my car purchase to push it too hard.

[blackraven]

Jack, there is another guy selling his X250 for about $2650. Let me know if you are interested, I will PM you his email. The unit has been checked out by Pass Labs and they know the guy as I called Pass about the unit. He is supposedly in the audio industry. He is selling it because he wants to move up the the X350.

Stay away from the older X150 (not the 150.5). Pass Labs told me that the old X150 is not the same as the X250 and above. It does not sound the same and there are different electronics in it.

[Mr Peabody]

Jack you might consider the Pass integrated amp, it's 150x2 into 8 ohms. I would like to hear Pass and Dyn.

In case my prior post gave the wrong impression on Pass preamps I want to share a response to an email I sent to my Pass dealer. Despite his response, a 2 chassis preamp by Pass at under $2k still has to be a deal, that's what I see the X1 at on Audiogon. I'm sure it's no slouch, it just sounds like large improvements were put into the XP10.
Hi Bryan,

It’s good to hear from you again. I’ll be happy to help with anything I can.

The XP-10 is actually better than the old three-chassis Pass Labs X0.2, and the X0.2 was the upgrade from the X-1—that’s how good the XP-10 is!

I’ve helped many hundreds of people own and enjoy PASS preamps, and I’ve never heard of anyone that preferred the sound of the X-1 over the XP-10.



In some ways the X-1 is more transparent than the XP-10, but the X-1 is also not as smooth, has less resolution, has more noise, less bass, and does not image as well as the XP-10.

[Jack in Wilmington]

Jack, there is another guy selling his X250 for about $2650. Let me know if you are interested, I will PM you his email. The unit has been checked out by Pass Labs and they know the guy as I called Pass about the unit. He is supposedly in the audio industry. He is selling it because he wants to move up the the X350.

Stay away from the older X150 (not the 150.5). Pass Labs told me that the old X150 is not the same as the X250 and above. It does not sound the same and there are different electronics in it.

Thanks for the warning about the older x150's. I like the idea of being able to see the X150.5 before buying. This unit is supposed to be less than 6 months old and in mint condition. I'll also save on the shipping. I will check out the x250, thanks for the link.

[Mr Peabody]

Jack, what will you use for a preamp?

[harley .guy07]

. I would like to hear Pass and Dyn.


I will say the I am totally impressed with the synergy of Pass and Dynaudio. I have an older series and a more affordable series than the contour. The X150.5 makes my lowly Audience 60's sound like much more than they should for their original retail price. While I do want to upgrade someday I will say that I am totally impressed by what these speakers can do with this amp on them. I will say for sure that this amp on them has taken the refinement of the speaker themselves as far as the way the sound now up several notches over anything in my system in the past or any other time I have ever heard this speaker. I would be willing to say that the Pass 150.5 has taken my small Audience 60's to a level much higher than all of us would ever have thought possible.

[Jack in Wilmington]

Jack, what will you use for a preamp?

I'm not sure. I have an older Audio Research LS8 pre that has been in the closet for awhile that I would hope to sound good with the Pass. I could also use my existing Anthem as a pre if I need to. I'd like to take my time and try some other preamps both SS and tubed to see what sounds best.

[Mr Peabody]

As preamp for Pass I'd recommend going with a true balanced unit as to take advantage of Pass's balanced symetery technology. The X1 may not be on par with the XP10 but as a two chassis unit, and with Pass stamped on it, I'd suspect it is still a good performer. I'd be interested in hearing how the ARC sounds with the
X250, I personally feel the two have quite different sonic characters and may not have synergy, but Frenchmon has a friend who matched ARC pre with a Mac amp and says it sounded really good, and that match surprised me as well, so you never know. I suppose first thing is to get the amp and to see if you even like it :).

[Jack in Wilmington]

I can't really imagine not liking the Pass, it may be a matter of getting a pre that has synergy with the Pass.

[blackraven]

On my short list of preamps are Pass, BAT, CJ, Atma-Sphere and AR. Hopefully in 1 year there will be some nice used preamps on the market. I am hoping to get $1K for my Van Alstine preamp and keep my budget for a used one at about $2K.

I want one of these-

Atma-Sphere music systems, inc. (http://www.atma-sphere.com/Products/#MP-3)

Atma-Sphere MP-3 by Todd Warnke (http://www.enjoythemusic.com/magazine/equipment/0401/atmaspheremp3.htm)

I could always use another room heater to go along with the Pass.

This is also on my short list-

PARASOUND JC-2 JC-2 (John Curl Design) PREAMP Recommended Component" 2013 - Stereophile-CLASS A | Solid state | Nashville, Tennessee 37205 | AudiogoN - The High-end Audio Community (http://app.audiogon.com/listings/solid-state-parasound-jc-2-jc-2-john-curl-design-preamp-recommended-component-2013-stereophile-2013-10-06-preamplifiers-37205-nashville-tn)

[Feanor]

There a multiple of these great amps for sale at this very moment -- I get hot sweats thinking about it, such is my lust for one of these.

The low price for the X150.5 is $2500 with free State-side shipping: a very good deal, (here (http://www.audioasylumtrader.com/ca/listing/Amplifier-SS/Pass-Labs/X150.5/FREE-SHIPPING/96108)). For the XA30.5, $2895, (here (http://app.audiogon.com/listings/solid-state-pass-labs-150-5-power-amp-w-blue-meters-2013-10-17-amplifiers-07044)) which is also bargain (always assuming the seller is legit of course).

I think I'd go for the XA30.5; I know it would have adequate power from my low to moderate volume listening. The XA30.5 is 30 wpc into 8 ohms class A BUT has an additional 6 dB headroom in AB mode. I.e. it's really a 120 wpc amplifier.

http://images.audioasylum.com/usr/y2013/10/96690/036.JPG

[blackraven]

I saw that XA30.5 for sale. It is a real bargain. Feanor, my Maggies rarely cross over from Class A to AB according to the Bias Meter on the front of my X250. Only on dynamic bass heavy music played at moderately loud levels does it cross over to AB.

By the way, I was looking at some reviews of Pass amps and came across this user review (posted below) comparing his Pass X150 to his Parasound A21 and Krell amps. I found it interesting that he is calling the A21 warm. I find it neutral compared to the slightly warmer sounding X250. This differenc f opinion may be due to the fact that the original X150 has different electronics than the X250. One thing that I have found with the X250 is that it is a little more laid back than the A21 and that high frequencies are better with the A21 in some respects. Cymbals are more prominent with the A21 and maybe a little more natural but the X250 is a bit smoother. This is consistent with a couple of reviews that I have read about the X250. I have been using the tweeter resistors on my Magnepans, I guess it is time to remove them.

Here is the review of the Pass, A21 and Krell-

"Pass X150 vs. Parasound Halo A21 & Krell KAV-400xi
This is a consumer review of the Pass X150 stereo amplifier, compared and contrasted w/Parasound Halo A21 and Krell KAV-400xi.

Review System:

Preamp: Arcam A75+
Amp: Pass Labs X150
Universal Player: Denon DVD-2910
Speakers: Dynaudio Audience 82's (frequency response rated 25hz-25khz)
My ridiculously small room: 10' x 10' [I know I have broken all audiophile rules w/my choice of speaker]

I recently purchased the Pass X150 and had a 30-day, in-home trial. It is a 150 wpc amplifier that reportedly runs in pure class A up to 50 watts/channel. This is quite remarkable since most listeners never reach this level of power continuously. After the first 50 watts, it switches to class A/B operation. It runs pretty warm but I can touch the (large) heat sinks and not get burned. It seems even the fascia of the amp serves as a heat sink since it is sometimes warm as well. The front of the amp is very thick aluminum (?) on top of aluminum in a silver-gray finish. It is very utilitarian/masculine looking. Other amps may not want to pick a fight w/it based on appearance. The blue LED's indicating power/standby are a little annoying, if watching a movie, but can easily be covered w/a cloth resting on the protruded aluminum on the front. It's pretty hefty at about 60-70 lbs, for being the entry-level amp in the series. However, there is nothing entry-level about the sound.

THE BIG PICTURE

I tried to start this review discussing particular characteristics from bass to treble. But that just wouldn't be right; it is contrary to the nature of the amp.
This is the defining characteristic of the X150; it has an overall sound of organic delivery and focuses on the whole of music. It doesn't favor any particular frequency range; in this way it doesn't seem to highlight any particular hi-fi characteristic. The presentation is of the music and that is this amp's concern. You may get better delineated bass from a Krell, which is brutal in the mids/highs (IMO). You may find more seductive midrange from tubed gear, which often rolls off the bass and highs. But consistency top-to-bottom, neutrality if-you-will, is this amps trademark. It will reveal the "character" of components upstream/downstream; this includes the recordings themselves.

Some may think this amp does hi-fi imaging/soundstaging. If by that they mean, it has a convincingly large soundstage and pinpoint imaging, they're right. However, if the recording isn't well sorted, that's how it comes through the X150, while preserving the musical enjoyment. On good recordings all of the placement cues are there, w/solid life-sized images and a walk-in-and-around 3-dimensionality. The stage is not forward (in front of the plane of the speakers), nor recessed (behind the plane of the speakers). It seems, once again, neutral; starting at the plane of the speakers and extending to the sides and back. It's stage is both wide and deep.

The X150 does have superior soundstage depth compared to other amps I've had in my system. More recently I reviewed the Parasound A21 in my system (all other components/accessories the same). I like the A21; it is an overall good performer, but I had reservations about transparency (compared to my 50 wpc Arcam integrated). Having installed the Pass amp my observations seem to be confirmed in this regard. Because of the Pass amps transparency there seems to be more of an invitation to walk through the soundstage and around the performers. I wouldn't say its like holography, per se, since the images are focused; however, the images don't seem "fat", for lack of a better word, as they did w/the Parasound. This may be the result of perceived added warmth w/the Parasound. On the other hand, the Pass doesn't give the impression of bleached/pale images as I feel Krell does.

Which brings us to tonality. If Krell is winter and Parasound Halo is summer, then Pass Labs is spring and fall. That's my kind of weather! It neither jolts you to tears of pain when listening to violins, nor makes females sound somewhat "fat". It is simply a refined and smooth sounding amp, that portrays tonal colors and shadings accurately w/o going to extremes. By smooth I mean, there's not a gritty/grainy characteristic to the sound. That happened sometimes w/my Arcam on its own at louder levels, probably due to clipping. The Parasound also is smooth like the Pass Labs, but w/the added warmth.

It seems like I've been beating up on Krell. So I just want to say I haven't heard better bass from another amp than the Krell. The detail and power in the bass from this thing was outright astonishing from the diminutive-sized amp. It does have the edge over the Pass in this regard. The Pass and the Parasound I thought were pretty comparable in the bass.

CONCLUSION

The Pass Labs X150 is a coherent, neutral, powerful, smooth, 3-dimensional, musically satisfying solid-state amp. This is the best I have heard in my system. I would specifically recommend it for those who want their systems to present music as a whole and be as neutral as possible (as opposed to those who like to dissect, or those who want an amp with added character). It does all of the hi-fi things one would expect from a dedicated amp, but in a civilized and even-handed way. I would recommend the Parasound A21 for someone who has a leaner sounding system. The Krell sound I think goes best w/a system that is a little warmer/juicier in nature.

These are all good components; but the Pass worked best in my system. And, yep, I'm keeping it. YMMV"

[harley .guy07]

Yeah that's the way I felt about my Pass. I will say that I have heard a lot of amplifiers over the years and by far the Pass amps are the best to my ears and most likely be where I stay with my amp selections if I ever change from my 150.5, I just don't see the point going away from the sound I love. I love the way the Pass makes music, not just noise!!!

[Feanor]

Very interesting comments & review.

Transparency, air, and palpability are my top priorities in an amp; at the same time I hope for reasonably tight bass, smooth, extended highs, and good dynamics. Warmth and a "liquid" mid-range aren't so important. The Pass Labs sound like they're up my alley.

Interestingly my Class D Audio SDS amp has all of these good things in decent measure except the smooth highs; it's highs are bright and can be quite shrill on some recordings.

In good conscience I shouldn't spend more than $1200 or so on an amp, but I might be tempted to go as high as $2000 for an X150. While it might not have the finesse of the 150.5, it apparently has the Pass characteristics.

[frenchmon]

Thanks for posting that Raven! I really enjoyed that! the Krell is a different type of amp in my opinion from the Parasound and the Pass.

On another note Raven....you should give some thought about paring your Pass with a tubed preamp! Not one as warm as the Pass, more like a ARC tubed preamp would do the trick. I really like Peabodys Pass amp and you have one as well....very good choice. Try a tubed preamp with it.

[Mr Peabody]

I would talk with some one tech savvy or an Atmosphere user before buying one to use with solid state just to make sure impedance etc. would work, the OTL are quite different animals.

[blackraven]

Thanks for posting that Raven! I really enjoyed that! the Krell is a different type of amp in my opinion from the Parasound and the Pass.

On another note Raven....you should give some thought about paring your Pass with a tubed preamp! Not one as warm as the Pass, more like a ARC tubed preamp would do the trick. I really like Peabodys Pass amp and you have one as well....very good choice. Try a tubed preamp with it.

I like the idea of a tube preamp. I like what tubes bring to the table but I also wonder about the synergy between a Pass amp and a Pass preamp.

That review I posted, the guy says that the A21 is warm. I find that the X250 is warmer than the A21 in my system. The big diffence between the 2 amps is transparency and air. The A21 just does not have nearly as much. Resolution and texture of the music is also better with the Pass.

[frenchmon]

You may find the added texture of tubes a bit more enjoyable as well as a more plesant tubed mid-range. I find tubed mid-range is hard to beat with SS....but thats just my opinion. Raven...like I once mentioned to Peabody, tube lovers gotta have tubes in the chain some place....just don't seem right without them.

[blackraven]

You may find the added texture of tubes a bit more enjoyable as well as a more plesant tubed mid-range. I find tubed mid-range is hard to beat with SS....but thats just my opinion. Raven...like I once mentioned to Peabody, tube lovers gotta have tubes in the chain some place....just don't seem right without them.


Thats why I like my tube Preamp and tube DAC.

[Feanor]

You may find the added texture of tubes a bit more enjoyable as well as a more plesant tubed mid-range. I find tubed mid-range is hard to beat with SS....but thats just my opinion. Raven...like I once mentioned to Peabody, tube lovers gotta have tubes in the chain some place....just don't seem right without them.
OTOH I never missed my former tube preamp.

So, do you subscribe to the theory that tubes in the repro chain, e.g. a tube preamp, can mask defects elsewhere in the chain, e.g. in the power amp?

My theory is that they can. However Morricab at Audio Asylum articulately insists that masking doesn't happen, and that the only real solution is to remove disagreeable sound at source. In the above example according to him, one must change the power amp if it is the source of the problem.

[Mr Peabody]

I may be thinking of the wrong use of "mask" but tubes don't necessarily mask anything. I've heard tube gear that can be as revealing as solid state. Certain tube gear can change the presentation or maybe even the sonic balance but if it's quality tube gear nothing should be masked.

[Feanor]

I may be thinking of the wrong use of "mask" but tubes don't necessarily mask anything. I've heard tube gear that can be as revealing as solid state. Certain tube gear can change the presentation or maybe even the sonic balance but if it's quality tube gear nothing should be masked.
To clarify what I mean by "mask", I don't mean to imply that the tubes veil the sound in perceptible way. Rather my hypothesis is, specifically, that the relatively high 2nd and/or 3rd order harmonic distortion produced by tubes, which is inoffensive, masks the irritating higher order harmonic distortion that is typical of solid state because of the use of negative feedback in s/s devices.

[blackraven]

To clarify what I mean by "mask", I don't mean to imply that the tubes veil the sound in perceptible way. Rather my hypothesis is, specifically, that the relatively high 2nd and/or 3rd order harmonic distortion produced by tubes, which is inoffensive, masks the irritating higher order harmonic distortion that is typical of solid state because of the use of negative feedback in s/s devices.

What difference does it make as long as it sounds good? Every speaker and just about every piece of gear sounds different. And recorded music sounds different than if you were listening in the studio.

[frenchmon]

To clarify what I mean by "mask", I don't mean to imply that the tubes veil the sound in perceptible way. Rather my hypothesis is, specifically, that the relatively high 2nd and/or 3rd order harmonic distortion produced by tubes, which is inoffensive, masks the irritating higher order harmonic distortion that is typical of solid state because of the use of negative feedback in s/s devices.

It has been my experience, the opposite with a very good tube rig. IF you have good tubes, in your amp/preamp, they should be very clear and transparent. IF so they will let you hear the grain in your inferior SS in the chain. The better the tube/SS and the amp/preamp/integrated is, the more reveling it will be...and thus, your inferior CD's and records will be exposed as well. I find a good tube tells the truth.

When played at louder levels, my NOS tubes have exposed my $600 phono stage as having grain. Some time next year I will have to bring it up to speed as my other gear. But I only discovered it when I went to a expensive KOBE TEN tube. I had no idea what the issue was until I asked around. My amp/preamp is transparent and will let the sound of my sources pass through. My Rotel had a very strong house sound that imparted its character upon my CDP. Not so with the Vincent. I remember I had a Bel Canto DAC/preamp that also let me hear my CDP, but not the Rotel.

[Feanor]

It has been my experience, the opposite with a very good tube rig. IF you have good tubes, in your amp/preamp, they should be very clear and transparent. IF so they will let you hear the grain in your inferior SS in the chain. The better the tube/SS and the amp/preamp/integrated is, the more reveling it will be...and thus, your inferior CD's and records will be exposed as well. I find a good tube tells the truth.

No question that the better the amp/preamp, the more clear & more transparent the sound.

But I don't think that what you're saying doesn't conflicts with the idea that the tube distortion profile (let's call it) of the tube preamp "masks" the less agreeable distortion profile of the power amp.

[Mr Peabody]

I think we are all on the same page but differing on terminology. I have found with tube gear like Octave Audio and solid state like Pass that a very enjoyable sound can be achieved via both technologies with no loss. Acknowledging audio is subjective and tastes may vary :).
No question that the better the amp/preamp, the more clear & more transparent the sound.

But I don't think that what you're saying doesn't conflicts with the idea that the tube distortion profile (let's call it) of the tube preamp "masks" the less agreefffffable distortion profile of the power amp.

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