Bullet bitten and trigger pulled

OK, resistance was futile following the commanding leadership of harley, Mr P, and blackraven I'm going Pass Labs.

I've bought a used Pass Labs 150.5, (on AudioAsylumTrader). I'll be waiting breathlessly for its arrival. I considered one of the XA30.5's available be decide the lower price and heat output of the former was the way to go in my case.

https://passlabs.com/images/uploads/...ain__large.jpg

Wow, it's like an audio epidemic. First Mr. P and now it's spreading. I was leaning towards Bryston, but now I'm swaying the other way. Congrats Feanor, hope all goes well in shipping.

Bill, congrats on the new amp. You won't be disappointed. It will transform your system. I am looking forward to your impressions. If you don't like it, blame Mr P., he started it all:)

Epidemic is right, LOL. Congrats Feanor, I will be anxious to hear your report as you sound like one who likes a very neutral presentation. I think if the Pass is to your liking and you can swing picking up the 8001 you will be on the way to a very enjoyable system.

Some specs of the 150.5 that surprised me (more or less):

• Wpc @ 8 ohms = 150; @ 4 ohms = 300 -- not all that surprising from such an auspicious maker but it's good to have it confirmed
• Weight = 62 lbs -- heavy compared to other amps I've owned, including the fairly heavy Adcom GFP555II, and heavier than the pair of my Monarchy SM-70 Pro's.
• Input impedance = 30/20 kOhms, (balanced/single-ended) -- I would have assumed higher; probably speaks for using an active preamp
• Damping factor = 150 -- fairly low for an s/s amp
• Maximum in class A = 10 watts -- not really surprising; this is a pretty common value for modern, quality AB amps
• Power consumption at idle = 200 watts -- wow! pretty high, plus best sound quality is best when 'On' for 1+ hours. But I don't think I leave mine 'On' 24/7, just leave it in 'Stand By'.

See X.5 series specifications HERE.

Wow cool. I think we are going to have to change this website name to Pass labs review instead of Audio Review. I think if we started a Pass only thread everyone would be there and all the other topics would have no one there. You will love the 150.5, I know i love mine. Let us know what you think and I won't be surprised when it blows you away and be very very surprised if it doesn't

I haven't heard Blackraven mention it but I can definitely tell a difference in the sound once the amp warms up, I usually turn it on ahead of time if I know I will be listening to shorten the time. It's a very similar effect tube amps have, once it warms up things seem to be more open and overall better.

Also, I forgot to mention it to you but the Pass amp will need to be plugged into AC about 24 hours before it begins to sound the way it should. I couldn't wait myself, I knew out of the box I was going to like it but the next day the sound was improved, especially in the lower region.

I've heard damping factor really doesn't have to be that high and it's sort of an overrated spec. The Pass bass is about right to me, it doesn't have the iron grip of Krell, but the bass is still very detailed and controlled, allowing enough plum to sound natural.

Bill, do you use a sub with the Maggies? Just curious, I don't remember you ever talking about one but most seem to add one with 1.6's.

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Originally Posted by Mr Peabody

Bill, do you use a sub with the Maggies? Just curious, I don't remember you ever talking about one but most seem to add one with 1.6's.

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Originally Posted by Mr Peabody

Bill, do you use a sub with the Maggies? Just curious, I don't remember you ever talking about one but most seem to add one with 1.6's.

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Yes I do use a sub with the Maggies. I have a PSB Subsonic 5 with the low-pass set to 50 Hz, (the minimum for the sub); the Maggies run full range.

My system is currently configured like this ...

Attachment 9513

Tonight I did a little benchmarking with my current amp, the Class D Audio SDS-258. Understanding what I currently believe to be the strengths & weaknesses of this amp will help me understand the same for the new amp, the Pass Labs X150.5

To do this I am using my favorite reference recordings -- which include several Reference Records, (pun intended).

The SDS-258 actually has some great strengths -- remains to be seen if the new amp is better/equal/not so good:

• Very fine transparency, air, and separation of voices & instruments
• Very good soundstage and palpability of performers in it. The soundstage, to my ear, is just as wide, deep, and high as the recording provides -- as demonstrated by the ability of the amp to distinguish recordings from each other
• Lean, precise bass; not bloated or overhung (like my former NAD C270 or Forte Model 5)
• A clear, neutral mid-range the conveys instruments and vocals realistically, (unlike the Forte Model 5 that just sounded weird to my ear)

But there is definitely downside to the SDS:

• Highs that are extended but bright; not "grainy" or "etched" as those words are typically used, but definitely bright. On good recordings this isn't a big problem for me, but on less than good recordings highs can sound unpleasantly shrill.

Bill, my X250 has more texture to the music when compared to my CDA-254. Both have good air and transparency but the Pass is more musical and detailed. I find treble to be pushed back with the Pass. It's my only complaint about it. I have not noticed any change in sound after the amp has been on for an hour but I have not been listening for it.

Blackraven what do you mean by "pushed back", is it further back in sound stage or are you saying rolled off? I find the treble very good in my system, I wonder if your effect is due to tube compliment of associated gear.

Bill, when you are noting the sound of the digital amp are you using the ARC preamp?

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Originally Posted by Mr Peabody

Bill, when you are noting the sound of the digital amp are you using the ARC preamp?

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Yes, my comments are based on driving the CDA SDS-258 with the ARC LS9 and a balanced connection.

However the general characteristics of the SDS were the same with the passive preamp I was using recently. The contribution of the LS9 is principally improved dynamics.

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Originally Posted by blackraven

Bill, my X250 has more texture to the music when compared to my CDA-254. Both have good air and transparency but the Pass is more musical and detailed. I find treble to be pushed back with the Pass. It's my only complaint about it. I have not noticed any change in sound after the amp has been on for an hour but I have not been listening for it.

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Well the SDS-258 is a $600 amp while the 150.5 is $5,500 amp, so I will be ... uhmm ... "disappointed" if the latter isn't better in virtually all respects.

I won't miss the over-bright highs of the SDS provide the 'air' and overall naturalness are improved.

Mr P. I find the treble to be pushed back in the sound stage and less prominent when compared to my A21 and Class D amps. There is also less air in the treble but there is also no grain. I have tried various tube combo's and some are better than others. I have 0.6 ohm resistors in my Maggie tweeters which I will remove this weekend which will help by increasing the tweeter volume by about 1dB.

Bill, your 150.5 will sound different than the X250. The 0.5 series has a different sonic character and is supposed to be more refined. When do you expect to receive the amp?

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Originally Posted by blackraven

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Bill, your 150.5 will sound different than the X250. The 0.5 series has a different sonic character and is supposed to be more refined. When do you expect to receive the amp?

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Maybe there are "refinements" but I believe they are relatively slight.

When will I get the 150.5? Well with any luck the seller will be able ship today. Due to the high shipping weight, 75 lbs, it can't be shipped USPS, (my preference by a wide measure), so it going FedEx.

FedEx was telling him he need a Certificate of Origin to export the amp. This CoO would make it possible avoid Canadian import duty under NAFTA. However the CoO requires official documentation from the manufacturer plus notarization.

I told my seller to tell FedEx that his buyer, (that's me), would pay the duty in the absence of an CoO. It's easier, quicker, and possibly cheaper to just pay the duty than obtain a CoO.

N.B. Under NAFTA in theory a US product can be imported in Canada without duty and vice versa. But in practice it doesn't work out so well in case of a one-off, personal cross-border sale -- see above. In fact, a US buyer can end up paying duty on a US-made product that he buys from a Canadian seller, (and vice versa): this sucks but it's the way it is. The good news is that the tariff rate is fairly low.

I HATE FedEx; I always prefer the USPS and Canada Post option for being far easier and often cheaper. Coming from the US to Canada it's invariably cheaper because Canada Post charges a flat brokerage fee which is only $8.00 depending on the service selected.

Well Fenor.....congrats! I'm sure your ears will like the Pass...its a great amp man. When I first heard Peabodys I loved it. And your talking about power concumption just sitting at 200 watts...try a wopping 270 watts my Vincent uses just sitting.

Harley, you took the words out of my mouth...the PASS LAB REVIEW FORUMS!

Jack...go ahead and get the Bryston.....I'm sure you will still be in the same category. Which model where you considering?

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Originally Posted by frenchmon

Well Fenor.....congrats! I'm sure your ears will like the Pass...its a great amp man. When I first heard Peabodys I loved it. And your talking about power concumption just sitting at 200 watts...try a wopping 270 watts my Vincent uses just sitting.

Harley, you took the words out of my mouth...the PASS LAB REVIEW FORUMS!

Jack...go ahead and get the Bryston.....I'm sure you will still be in the same category. Which model where you considering?

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I was looking at the Bryston 4B-SST2 or the Pass X150.5

Bill, when I talked to Reno Hifi, they guy tried to steer me into buying an X150.5 because he thought the 0.5 series sounded much better than the older X series. So I suspect that there is some truth to that from what I have read. I considered buying an x150.5 but I paid about $1K less for the X250. I was also looking at a used ARC amp, but Reno Hifi steered me away from it saying that he preferred the sound of the Pass amps.

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Originally Posted by blackraven

Bill, when I talked to Reno Hifi, they guy tried to steer me into buying an X150.5 because he thought the 0.5 series sounded much better than the older X series. So I suspect that there is some truth to that from what I have read. I considered buying an x150.5 but I paid about $1K less for the X250. I was also looking at a used ARC amp, but Reno Hifi steered me away from it saying that he preferred the sound of the Pass amps.

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I was temped to look for ARC to match my LS9 preamp; (I like the ARC cosmetics). I might have gone for a late model, non-class D model, say an SD135. I'm sure they would have been nice but my ambition for a long while has been for a Pass Labs.

Come to that, I have some second thoughts along the line that I ought to have got an XA30.5 which would have cost me relatively little more. Another amp might have considered is the Ayre V5XE, though I think it's a bit more "tube like" which isn't necessarily what I'm looking for.

I know there are supposed to be differences between the x and .5x series amps but I am just wondering how much? if Reno hifi is saying they recommend the .5 series then there must be more to it than just subtle but I would like to hear that for myself. Too bad everyone does not live close to Missouri or we could all get together and have Mr Peabody bring his x250 and I bring my x150.5 and we could have a Pass off!!!!! and see just how much difference there really is.

Harley...what is the .5 in the x150.5 ?

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Originally Posted by frenchmon

Harley...what is the .5 in the x150.5 ?

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I am not for sure other than they took the amps to the next level in the .5 update. 'm sure Raven would be able to tell you more than me since he talked to the main Pass Labs dealer about the difference. I just know from what I understand is that they are more refined than the older ones.

Honestly I would love to sometime hear one of the XA or XS series amps just to see how much more of that Pass love comes out in those amps over mine. As much as I love how mine sounds I would say that the XA or even better the XS amps would be like being in audio heaven. Too bad the XS amps are the price of a Mercedes and I will probably never be able to afford one on a good year not to mention the price of the associated equipment needed to give them their due.

A guy on AA had a X250 and upgraded to the X250.5, he made out like it was a pretty good upgrade. At the time I bought my amp the dealer didn't make out like it was a big difference, as I remember he stated the .5's are warmer. To my ears the
X250 is a really good amp and at the price they are going for used is a no brainer.

Wow, Feanor. That is a beautiful piece of gear.

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Originally Posted by kexodusc

Wow, Feanor. That is a beautiful piece of gear.

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Hi, Kex, good to hear from you; I think it's been too long.

Yeah, FedEx is reporting that it's on its way, and I'm really looking forward to it. For a while it's been a kind of dream of mine to own a Pass Labs amp -- I hope I'm not disappointed but there have been many endorsements.

Bill, I think that you will appreciate the extra slam that the 150.5 has because of its extra power, especially with Classical music. The 0.5 series is supposed to be a little more tube like with a sweeter midrange, better detail but a little less transparency than the older X150.

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Originally Posted by blackraven

Bill, I think that you will appreciate the extra slam that the 150.5 has because of its extra power, especially with Classical music. The 0.5 series is supposed to be a little more tube like with a sweeter midrange, better detail but a little less transparency than the older X150.

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I would hate to loose transparency! But things are relative: if the 150.5 is even as good as the SDS then it will be very good indeed.

Speaking of slam, adding an active preamp, the ARC LS9, to my system as really kicked up the dynamics. Indeed, I listened to Eiji Oue & Minnesota Symphony's version of Stravinsky's Rite of Spring, (Reference Recording RR-70) last night: this was the first time through the LS9 and the impact of bass drum and tympany was thrilling -- another hard act to follow but my expectations are high.

Feanor, seeing that the Pass has a much different sound signature than the ARC preamp, you may find some very good synergy!

Seeing that I have never been around a Audio Research solid state Preamp I have no clue how well they will work together but I like my Nuforce with the Pass but I am willing to bet the Nuforce P8 and ARC ls9 are very different from each other.

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Originally Posted by frenchmon

Feanor, seeing that the Pass has a much different sound signature than the ARC preamp, you may find some very good synergy!

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So, frenchmon, how would you typify the sound of the ARC LS9? One must bear in mind that the LS9 will sound a bit different than ARC tube models.

Among ARC preamps I have only ever heard the LS9 and, of course, have yet to hear the Pass 150.5. Further, I've never heard my current amp, (the CDA SDS), with anything else than a passive preamp, so it's hard for me to compare. But at this point I'll say that the LS9 seems very transparent and very dynamic. Also bass seems tighter and highs maybe just a little brighter. These latter characteristics might be explained entirely in terms of the LS9 being active rather than passive.

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Originally Posted by harley .guy07

Seeing that I have never been around a Audio Research solid state Preamp I have no clue how well they will work together but I like my Nuforce with the Pass but I am willing to bet the Nuforce P8 and ARC ls9 are very different from each other.

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Sound differences are a pretty save bet. But would you care to speculate on the differences between the Nuforce P8 and ARC LS9 might be?

Both are solid state preamps; the Nuforce P8 is newer; the P8 has an potentiometer volume control vs. the LS9'S relay-controlled resistor ladder; the P8 is single-end front to back while the LS9 is fully balanced. Of course these factors don't say much about the sound.

On the face of it, I'm glad the LS9's balanced output because this is optimal for the 150.5, as it is for my still-current Class D Audio SDS-258.

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Originally Posted by Feanor

So, frenchmon, how would you typify the sound of the ARC LS9? One must bear in mind that the LS9 will sound a bit different than ARC tube models.

Among ARC preamps I have only ever heard the LS9 and, of course, have yet to hear the Pass 150.5. Further, I've never heard my current amp, (the CDA SDS), with anything else than a passive preamp, so it's hard for me to compare. But at this point I'll say that the LS9 seems very transparent and very dynamic. Also bass seems tighter and highs maybe just a little brighter. These latter characteristics might be explained entirely in terms of the LS9 being active rather than passive.

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Hi Feanor.

The ARC seems to be more lively in presentation. Nothing boring about ARC. The Pass is more neutral and can be said to be on the warm side of things. The contrast in Both brands are dynamic....but the contrast in the two different sound temperatures( warm...lively)may make for a great synergy between the two.

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Originally Posted by frenchmon

Hi Feanor.

The ARC seems to be more lively in presentation. Nothing boring about ARC. The Pass is more neutral and can be said to be on the warm side of things. The contrast in Both brands are dynamic....but the contrast in the two different sound temperatures( warm...lively)may make for a great synergy between the two.

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That's good info! The LS9 does seem lively to me. I'm hoping it will work well as a comb.

You pretty much explain it right Feanor except that the Nuforce uses a digitally controlled switched attenuator for the volume control which to my knowledge is how they do all of their volume controls on their preamps.

Bill, I have a very lively preamp and DAC. They really pair well with the Pass. I find the Pass to have a more laid back presentation than my A21 and the Pass does well with a lively preamp. With the A21 I had to tone things down with tube rolling vintage 1950's tubes into my system. Since I got the X250 I was able to put the stock tubes back into my Van Alstine Preamp.

I think that the ARC will match well with the X150.5. No worries man!

Raven what tubes you got in the preamp?

Feanor...of course the best synergy you will possibly get would be from the matching preamp made for your amp, that way you get the sound the engineer intended from his designs, you would hear Pass Labs in all its glory as Peabody is hearing right now and as I am hearing with my Vincent....but out side of that....contrasting sounds from two different brand names normally will give that great synergy one seeks. The contrasting components usually play off each others weaknesses rather than being over the top from having the same strong attributes and the same weaknesses. You should enjoy a great musical presentation.

Frenchmon, I am using Electro-Harmonix 6CG7's in my preamp, they are the tubes that it came with. I was using NOS 1950's Raytheon Black Plates and 1950's Sylvania Black plates in my DAC. The EH's have great air, sound stage and transparency but were too bright with the A21. They sound great with the X250. I am using NOS RCA Clear tops in my DAC. I can't decide if I like the RCA Clear tops, NOS RCA Black Plates or my 1950's Tung Sol Black Plates in my DAC. The EH's in my preamp solved the treble problem with the X250. I was beginning to think that there was something wrong with the Pass as treble was pushed way back and had little air about it. The EH's fixed the problem, although I still think the A21 has better treble, more natural sounding.

Some people, including Pass Labs owners, might not have see this very interesting article about the design of the X.5 and XA.5 amps ...

Leaving Class A by Nelson Pass of Pass Labs

(The article is also available on the Pass Labs website.)

After reading the article I wonder if that lack of distortion is what Blackraven may be having some issue with when trying to adjust from the A21. After hearing and using many amps I find the Pass treble natural and easy to listen to. The treble varies from recording to recording. I can understand other amps maybe being brighter or more forward in the treble area but I find treble on the X250 to be very good. I also find myself wanting to listen to more piano as the Pass is able to convey a great sense of melody and the notes ring beautifully.

Blackraven when using the A21 you had to roll in warmer tubes and insert the resistors into the 1.6's, I'm just not sure if the A21 should be your reference for ideal treble. Distortion, as mentioned earlier doesn't always have to sound like the clipping kind, it can also be edgy, or lack of definition or other nasties. I also think your high end will improve a great deal with better cables.

Feanor I was checking out your ARC preamp, interesting yours stays on all the time like the XP10. I'll post this link in case any one else wants to check it out. ARCDB - LS9