July 2012


Pass Labs XP-10 Preamplifier & Pass Labs XA60.5 Mono Amplifiers
Two magnificent creations from Pass Labs!
Review By Anthony Nicosia

  Pass Laboratories Inc. was founded in 1991 by Nelson Pass who seven years later in 1998 stepped down as President in order to devote greater time towards the development of products. Through my conversations with Desmond Harrington, now the company's President, I learned that Nelson Pass designs the amplifiers and electronic crossovers while Wayne Colburn (who joined the company in 1994) is responsible for the preamplifiers, phono stages and DACs. They currently work together on loudspeaker design and truth be told they seem to always wind up collaborating on everything, with lots of great conversation going back and forth between them.

Looking to the website one is amazed with the amount of knowledge located there. Searching through various tabs and you will find in depth discussions on products, descriptions of Pass Patients, numerous reprinted technical articles which cover topics from "The Sweet Spot" to "Speaker Cables: Science or Snake Oil-" and even a safety information section. Of particular note was in the technical blog section called "Leaving Class A" (at this link), which made for quite an interesting read. I will leave it to you to spend a few hours sorting through the vast wealth of information there. As for today we will undertake a careful examination of the Pass Labs XP-10 line level preamplifier and XA60.5 Mono amplifiers. Pass Labs is located in Foresthill California only a short two hour drive north of my home. Once delivered a mandatory check for physical damage plus a quick system setup ensued to make sure they survived the trip in working order. Rarely does a combination of equipment take me so much by surprise as did this preamplifier/amplifier duo from Pass Labs. After two days of casual listening with nothing particular on my mind expect the pure joy of hearing my favorite recordings it was time to separate them for their perspective reviews. First a careful examination of each piece was done and then they were brought back together to be evaluated as a system.

XP-10 Physical and Technical Description
This XP-10 comes equipped with a remote control, a great joy for those like me who find it increasingly difficult to remove myself from the listening position once settled in. This remote comes equipped with simple intuitive controls designed in an effort to minimize any possible confusion for the user. Its hefty weight (made from billet aluminum) felt right at home with the high quality of other Pass Labs gear and fit comfortably in my hand. Duplicate features from the remote can be found on the left side of the front faceplate, controlling functions for muting, mode, input selections, left/right balancing, volume and pass thru (for use with a home theater processor). There is a centrally located alphanumeric display on the handsome billet aluminum front faceplate and a rather large round volume knob to its right.  Looking around to the rear of the unit are two balanced and three single ended inputs. There is also one balanced and one single ended outputs, in addition to an IEC outlet for the factory supplied power cord (or one of your own choosing). There is also a fuse holder just in case the need arises although it never did while in my system.

The factory recommends going the way of a balanced output to amplifiers whenever possible claiming it will "typically retain the character of the input mode, but offers less distortion, less noise, more gain, and more voltage swing, without compromising the sound. With balanced operation, the common mode rejection of the preamp reflects the intrinsic common mode rejection of the topology, the matching of the gain devices, and the matching of the attenuator channels. In this case we have been able to keep the total mismatch to about 0.1%, for a common mode rejection of approximately -60dB." For this review the quieter XLR inputs/outputs were used as my Oppo Digital BDP-95 CD player and Monarchy Audio SM70-PRO mono bloc amplifiers could accommodate this, as later did Pass Labs own XA60.5 amplifiers.

The XP-10 comes with 83 volume steps allowing greater control over listening levels than did their previous X model preamplifiers. After first unpacking then plugging in the unit give it twenty-four hours before attempting any critical listening as it uses high bias Class A topology circuits that require them to heat up to a certain temperature before sounding at their very best. This of course necessitates that the unit be powered up 100% of the time but you need not worry as the XP-10 is quite "Green".  It has a current draw of only 10-watts and is designed to never really be "off" even in the power down mode. For this reason if you must unplug the XP-10 or remove the power cord the twenty-four hour break-in period would need to start over for the unit to again reach its sonic peak. Like all Pass Labs equipment it too strives to minimize the number of components in the signal path. Lifting off the top cover revealed a carefully thought out design taking up every inch of space inside leaving no room to spare. It is easy to understand why a design improvement on the XP-10 necessitated a second or third enclosure for their XP-20 and XP-30 models respectfully.

A First Listen With The XP-10
The XP-10 preamplifier was coupled to my reference Monarchy Audio amplifiers using balanced inputs and outputs while the first loudspeakers to see action were my Martin Logan Sequel II's. The reason for the switch over to these rather than staying with my Von Schweikert VR-35's reference loudspeaker was because of the difficulty I had previously noted getting them to throw a proper soundstage in my room. While trying different physical manipulations with regard to loudspeaker placement they never did truly satisfied me in this regard. Listening with this Pass Labs system for a few days made me think things might change with the addition of the XP-10 and to my great delight doing so did help a great deal. I sat their astonished as recording after recording produced a soundstage that snapped properly in place without so much as even a toe in from the ML's. Not only that but my Monarchy amplifiers never sounded quite this good. Listening to intimate performances by John Denver on the John Denver Live SACD (Super Audio CD Legacy js 65183) recorded at the 1995 Wildlife Concert has been always a pleasure. Today though with the addition of the XP-10 it sounded even better still. Even though this preamplifier came with a balance adjustment it was never needed as channel balance always seemed spot on. Replacing my highly rated Aesthetix Calypso tube/hybrid preamplifier was asking a lot and while there were indeed differences especially being a tube versus solid-state design, the XP-10 was never anything but an absolute pleasure to have in my system.

My first worry was losing the wide soundstage a good tube preamplifier can produce but much to my delight that problem never arose and on "Rocky Mountain High" with the ML's it threw an immense soundstage. The female vocal on "Country Roads" could be heard with distinction correctly placed in the background singing softly behind John Denver. Ambience was also very good with the proper reproduction of the small intimate acoustic hall where this CD was recorded. To describe the XP-10 I would have to say it was more relaxed almost tube-like but without losing detail. Rather than being aggressive or bright as lesser solid state preamplifiers can sound, this one captured the essence of performances others seemed to just glaze over. During an audition of the song "Poems, Prayers & Promises" my connection to the music felt so strong I was compelled to share my experience with others. Here one could feel the true mood of the performer as he reflected back upon his life with vocals being truly transparent and clear. Switching back over to my beloved VR-35 loudspeakers for the rest of the review period I started with a favorite CD of mine, YO-YO MA & FRIENDS Songs of Joy & Peace [Sony Classical 88697-24414-2]. Here the cello in "Dona Nobis Pacem (Give Us Peace)" was heard in full detail without tipping the scale towards edgy or grainy but rather quite open, transparent and musical. The tonal character of the instrument was rightly reproduced to sound close to that of a real cello with the body of the instrument sounding alive and natural.  Diana Krall's vocals on "You Couldn't Be Cuter" had a touch of midrange magic similar to what one would expect from tube good preamplifiers. Being solid-state in design it did not need one half an hour to warm up before sounding its best, just start your source component and to listen to music at its' finest. With some preamplifiers I have found it difficult to find just the right spot on the volume knob with music being either too soft or too loud. Wayne Colburn's 83 step controls found just the right spots for me and my system, a perfect match.

The Rolling Stones Let It Bleed SACD CD (abkco 90042) has many classic Stones songs, one being "Midnight Rambler".  Here rapid transients were reproduced with apparent ease with images locking tightly in place.  Vocals were simple to locate within a well-defined soundscape of great width.  Harp, guitar, drums, percussion and bass existed separately in individual spaces distinct from one another. The layering of the choir on the opening of "You Can't Always Get What You Want" displayed great depth front to back as well as width and height. Mick Jaggers voice was powerful and full while Keith Richards' guitar located off to the side was easily recognizable and in full detail.  Dynamics were strong as the ability of this preamplifier to quickly shift from soft to loud passages never posed a problem proving to be one of its stronger points.

The "earthy" quality of Tracy Chapman's vocals on Our Bright Future [Elektra 514061-2] shown through giving an intimate sense to her overall performance. While lacking some of that warm and fuzzy you are there feeling found with tube preamplifiers on "I Did It All" the solid-state XP-10 displayed an overall sense of transparency great enough to make me sit up and take notice. Fingers gliding across strings on the neck of the guitar were easily discernible as the texture of chords added realism to the song. Having others over who are not audiophiles sometimes helps to put things in perspective. When playing a demo CD distributed by Usher Audio which was created for promotional use my non-audiophile friend commented how real it all sounded, as if they were playing the congas right there in the room just ten feet away. It was now time to drop in the Pass Labs XA60.5's pairing them with my reference Aesthetix Calypso preamplifier and to put the XP10 aside.

In Steps the Pass Labs XA60.5 Mono Amplifiers
Physical and Technical Description
Nelson Pass has been making amplifiers for a very long time, his first commercial venture being the Threshold  800A back in 1975 when he founded  that company. Barely over one hundred units were made and happily I still own one of those. It was bought second hand when only one year old as the owner decided not to take this large ninety pound amplifier with him when moving out of the San Francisco Bay Area. It took me all of one second to decide it would be mine and has remained with me ever since. Today Nelson Pass is making amplifiers for Pass Labs and this part of the review will concentrate on one such pair.

The XA60.5 mono bloc amplifiers feature sixty watts of Class A power into 8 Ohms while weighing sixty-two pounds apiece or a total of one hundred twenty-four pounds for the pair. Appearance wise they sport a stylish looking billet aluminum (like with the XP-10) front faceplate with a recessed display meter, standby mode button, attractive blue lighting and some side heat dispersing fins angling upward rather than the traditional style of pointing straight out to the sides left to right. This slopping heat sink design serves the amplifier in multiply ways as it is able to hold twenty power MosFET's each ( forty total) and have the ability to dissipate a couple hundred watts efficiently. These fins also hold everything together as the top, bottom; front and real panels all bolt onto it, thereby simplifying assembly. Lastly and quite simply, they look great and that is nothing to be ashamed of. Their beauty only adds to the joy of their musical prowess and were a pleasure to openly display on the top, rather than inside, of my Salamander Audio Rack. Peering around towards the rear of each unit one finds an IEC connector, RCA/XLR inputs, a power off switch, fuse holder, a pair of handles to aide when lifting, a signal ground connection and a pair of five-way binding posts for external turn-on control.

Removing the top cover reveals the heart of the XA60.5 with its large 1KVA toroidal transformer. We are talking very large indeed as it takes up about one third of the space inside the amplifier. Running in Class A allows it to draw a high constant current even at idle which with its 180,000uF of capacitance allows for the storage of a great deal of energy to aide in the realistic reproduction of those demanding musical transients.  Producing sixty Class A, or 120 Class AB Watts with a low factory rated 1% distortion, the XA60.5 is able to store sufficient current for the immediate delivery to musical peaks.

"Our Meters Don't Go To Zero"
Taking a look at the company's Technical Blog selections there was a very interesting article written by Nelson Pass in 2008 called "Leaving Class A" (link here)  that I mentioned in the opening paragraph of this review. The two following excerpts mentioned below come from that article:

"The meters on our amplifiers are different. They reflect the current consumption of the amplifier, and when the amplifier is operating, they don't go down to zero like the meters on other amplifiers. This is because the electrical current consumption of our circuits has a fairly high value at all times, a property called the bias. The bias current runs through the amplifiers at a minimum value, determining the class of operation – Class B, Class AB, or Class A.

Class B has no bias current, Class AB has a moderate bias current, and Class A has a high bias current. Class AB push-pull amplifiers are hybrids between Class B and Class A. Class AB run Class A at low power levels, and become Class B amplifiers at output currents determined by the bias.

For several years Pass Labs has specified the nominal wattage's at which our amplifiers leave push-pull Class A operation into an eight ohm load."

"Like all bias decisions, the amount of single-ended bias and push-pull bias is a balance between performance and efficiency. The bias is generally set at a level suited to the heat dissipation capacity of the hardware. At Pass Labs the bias is set to the value which raises the heat sinks 25 to 30 degrees C. above ambient temperature. The result is a heat sink which you can put your hand on for about 10 seconds or so.

As a practical matter, this means that our X (Class AB) amplifiers are biased to dissipate roughly half of their rated output power. The XA (Class A) amplifiers are biased to dissipate roughly three times their rated output power.

The whole point of going to this trouble is to build an amplifier which sounds as good as possible. We find that this is achieved by building a simple amplifier which is intrinsically distortion-free. Getting that depends on a high bias.

Measurements are helpful at illustrating the differences between design approaches, but they are certainly not the last word in audio. If they were, then numerous other approaches would sound as good or better.

You can certainly imagine an amplifier which operates with a low bias current but has the necessary amount of negative feedback and/or circuit complexity to insure that it measures as well. Actually, you don't have to imagine it – such amplifiers are for sale.

Do they sound better? We don't think so. Our meters don't go to zero"

If you want to experience this amplifier at its best turn it on and wait until it gets hot to the touch as it sounds better when warm. Leaving it on for somewhere close to an hour should do the trick. Once again it is now time to leave the technical and physical discussions to move onto some real world listening evaluations.

Putting the Amplifiers Through Their Paces
The sound of the piano played by Ola Gjeilo on "Snow In New York" from the Stone Rose [2L48] CD sounded both true to life in size and in musical pitch. The XA60.5's added a welcomed sense of depth to the soundscape allowing the piano to seemingly exist in a real three dimensional sense within the confines of my room. One could almost see the creation of this instrument in proper length, width and height unfolding before my very eyes. It was a joy to hear each note played with a correct sense of timbre. The notes flowed forth rather than being slightly pushed forward as music had a greater sense of ease making long listening sessions more enjoyable. Not wanting to leave my 2L CD collection just yet it was time to bring out Flute Mystery composed by Fred Jonny Berg [2L 58] featuring the Philharmonic Orchestra with Emily Beynon on flute and conducted by Vladimir Ashkenazy. With the orchestra in the background the sound of her flute appeared to magically exist in the space between the loudspeakers playing with but never obscured by individual instruments accompanying it. Harp and flute intertwined together yet each retained their separate personalities creating a wondrous musical experience enhanced by the XA60.5's ability for sounding quite natural. During " Maria, Marie" from Carlos Santana's Supernatural CD the amplifiers were able to drive my loudspeakers quite hard producing thunderous bass felt deep upon my chest. While the meters did move during certain passages, signifying that the amplifier was switching from Class A to Class AB, I could not discern a noticeable change in sound. If you get the meters moving from dead center for longer periods of time you might notice a difference with the sound moving away from dead smooth but it was not a night and day difference for sure. Please understand in the interest of being quite thorough I am being very picky here and this is only in relation to its Class A sound quality which is very high and worthy of great praise.

The opening guitar sequence on "Free Fallin' " from Tom Petty's Anthology Through The Years CD [M-C-A 088 170 177-2] had a magical sparkle to it sounding high pitched but never shallow or thin, a positive testament to these great amplifiers. The classic Joni Mitchell CD, Blue (Reprise 2038-2) in HDCD format was another pleasure to revisit. Here on "Carey" the soundscape was neatly laid out before me with clearly defined space defining musicians and singers both lead and background.  There is nothing like a good Joni Mitchell performance. It was indeed a great pleasure hearing her unique voice filling the open space between my loudspeakers, yet sounding as if emanating center stage directly in front of me. The range of her vocal talents was vividly displayed as the XA60.5's had no trouble quickly recovering from the many fluctuations of her vocal prowess. Notes from the piano fell upon my ears appearing to be just the right distance beneath her voice giving this instrument a sense of its appropriate height.  She really hits those high notes with a tonal quality unique to her singing style and these amplifiers never let me down with their ability to create the illusion of her performing live right there in the room. This CD was enhanced by the performance of these Nelson Pass designed amplifiers with their ability to play music with a beautiful sense of ease and naturalism. As much fun as it was listening to them it was time to give a serious audition to both XA60.5's and XP-10 as a system setup which is really where this review was headed from the very beginning. Besides after those first few days of casual listening with the both of them, my mind keep racing forward to the time when a more serious endeavor would be undertaken to evaluate their sonic merits in greater detail. So why wait any longer, lets us now begin.

As The Beatles Song Says, "All Together Now" (A System Review)
Sometimes two plus two equals four and other times it equals five. Maybe it was all that conversation between Nelson Pass and Wayne Colburn with a language seemingly all their very own which made this combination of gear sound so very good when played together. Yes they were great separately, each magical in their own right, but now this musical bliss seemed to step up a notch presenting a very good case for the purchase of both together. Hearing The Oscar Peterson Trio CD We Get Requests [LIM Records B002HTWYZ6] brought me back to the days of my illustrious youth when as young men we would  frequent out of the way jazz clubs in and around New York City. It would be better of course if you could actually hear what this combination of gear sounded like from my perspective and in my room (always the problem with reviewing and using words to describe actual events) but suffice to say it was "live". The opening triangle on "Corcovado (Quiet Nights of Quiet Stars)" located in the far left corner of the soundscape never before sounded so free of harshness, so very natural. As the song progressed things got even better with piano, double bass and drums all well-defined individually in space, crystal clear with excellent truth of timbre while the lightning fast attack transients of Oscar Peterson on piano was stunning. Impressing, me again much like before, when each piece was reviewed individually, was the correct impression of size with respect to instruments being reproduced. On the second song you could hear great inner detail from the drum brushes, or brooms, as they were laid down upon the drum skins.  Attack transients of piano keys fired back at me with ease as the double bass produced a nice solid foundation at times going deep down low on "You Look Good To Me". Intricate nuances of even the smallest details of instruments were always quite evident. While there might be even more detail found in some other preamplifiers and more power with different amplifiers this combination of the two together was extremely impressive each complimenting the others strong points while revealing very few weaknesses. If you do need a more powerful amplifier because of inefficient loudspeakers, a very large room, the desire to play music at extremely loud levels or a combination of any or all of these and decide to look elsewhere my suggestion would be to try something higher up in the line at Pass Labs. Here you should find other amplifiers capable of delivering all that and then some.

As for the preamplifier my only suggestion would be that if you are looking for that last drop of musical detail and will settle for nothing but the very best then by all means look into their other two preamplifiers (XP-20 @ $8600 or the XP-30 @ $16,000) which sell for considerably more. These are indeed a great value considering the performance they deliver and I must consider them a bargain in the realm of high-end audio. At listening levels normal for me when not in the process of reviewing but rather just enjoying the music these amplifiers were all that was needed and then some. When I mentioned smooth it was not in reference to a sound that was rolled off at the top and bottom frequencies but meaning instead very natural sounding. Often were the times when  a listening session lasted well into the night five and six hours at a stretch where not even the slightest fatigue from digital madness set in, a definite testament to this pair of audio gear from Pass Labs. Read a few of my reviews and you will quickly discover my love for the various CD's from the Norwegian company 2L. The CD Nidaros Domkor [2L 72] is a visit to the Nidaros Cathedral located in Trandeim Norway with its choir performance under the direction of Vivianne Sydnes, Organ performances by Torbjorn Dyrud with the String Quartet from the Trandheim Soloists. The layering of images of rows of choir singers was first rate as one could hear individuals within a row perform from a slightly separate space but clearly close by to the singer located on either side of them. There was ample power from the XA60.5's to recreate this event being held back only by the confines of my rooms own boundaries rather than any constraints put upon it by amplifier power. While it is true that it was possible to get the needles to move the sound was still first rate no matter what was played.

Playing rock and roll with the XA60.5/ XP-10 combo proved equally satisfying as demonstrated by Queens Greatest Hits [Hollywood Records 2061-62465-20 CD]. Crank up the volume, let the meters a bit then sit back to enjoy some rock solid bass equally appropriate for the occasion. While it is tough to pick a favorite from such a good company of songs I must profess a fondness for "Fat Bottom Girls" the song and maybe well you know. The important point here though is this was no wimpy setup where you get enjoyment out of only less complex soundscapes of Baroque music, small ensembles, vocals etc. but a combination of equipment that drew the best out of whatever you care to throw at it complex musical passages or not. It was enjoyable hearing everything from Willie Nelson to Prince played back through this duo from Pass Labs. My days and nights both started and ended with songs heard through them thereby enhancing my overall mood throughout the day to finish with a sense of peace just before sleep.  Speaking of Prince if you are a fan the three disc CD Lotusflow3R (NPG Records) is worth checking out. On "I like It When You Danced for Me" it was difficult to sit still.  Played back through this electronic combination of designs from Nelson Pass and Wayne Colburn the music gave me great enjoyment at a gut level as this dance song seemingly was intended to do. PRAT was obviously incredibly and made it impossible for me not to enjoy the music  heard on the song "Chocolate Box", starting with the opening drum sequence later to be joined by the sounds of a synthesizer and of course Prince on vocals. Try as I might it was just not possible for me to find a style of music that was not enjoyable to hear through this amplifier/preamplifier combination. If you have the funds available and music is important in your life you owe it to yourself to consider either or both of these when you are ready for your next purchase.

Summary
Please take heed of this warning found within the owner's manual of the XP-10. "There is an Extremely Small (but Non-zero) Chance That, Through a Process Known as Tunneling, This Product May Spontaneously Disappear from Its Present Location and Reappear at Any Random Place within the Universe, Including Your Neighbor's Domicile. The Manufacturer Will Not Be Responsible for Any Damages, Inconvenience or Mental Anguish That May Result From These Space-time Perturbations." After experiencing the XP-10 in my review system I found myself constantly looking around for persons unknown who might be lurking outside my house for a chance to drop by when no one was at home and well you get the idea. Maybe it was for me to find a big dog with a large bark that loves music. As you can by now guess it was a sad day when the XP-10 left my home to return to the factory. Do not let this preamplifier slip by you, give it a listen but remember afterwards you might just feel the urge to put some extra locks on that front door for a little added extra security. As for the XA60.5's they also are a high-end product worth auditioning and brought tears to my eyes when placed back into their respective boxes for return shipping back to the factory. Not only did they mesmerize me with their sonic attributes but their physical appearance won me over as well. You have just got to love those side fins extending upwards towards the clouds and that gorgeous faceplate with their large recessed meters that "don't go to zero".

This pair of preamplifier/amplifiers sounded close to a tube setup without having to actually use tubes in your system. An extended vast soundscape, holographic imaging, precise placement of musicians in the soundstage, instruments heard with excellent truth of timbre and vocal reproduction to die for, please how much more do you really need? If the answer is well maybe just a little my suggestion is to look upwards in the Pass Labs lineup to some more powerful amplifiers and perhaps even a step or two upwards in their preamplifier position to see what might be possible. For my money though these hit a comfortable price point while giving back an incredible amount of sonic pleasure. To top it all off this was my first review where only the factory supplied power cords were used instead of expensive aftermarket ones. During the review it never even dawned on me to try upgrading the sound by experimenting with ultra-expensive power cords as they sounded so good without. This one is a definite no brainer and both come HIGHLY RECOMMENDED whether purchased separately or better yet together as a system. Do not pass over these two creations of Wayne Colburn and Nelson Pass without so much as an audition for they seemed destined to become classics in their own right to fly off the production lines as fast as they are produced.

The Listening Environment
The review room is eighteen feet eight inches long by thirteen feet wide with loudspeakers and equipment kept on the short wall. The cathedral ceiling starts at eight feet from the short wall slopping upwards to reach a height of thirteen feet in the middle than returning to eight feet at the opposite end. The hardwood floor is partially covered by a nine by six foot oriental rug lying down the long ways facing toward the loudspeakers, placed dead center between but not under the listener or the audio system. The room has no doors but there are two openings. One opening is in front of the right loudspeaker giving access to the hallway while the other is behind the listener's position opening to a formal dining area. There are three floor standing acoustical panels one in each corner behind the loudspeakers and another in front of the fireplace with numerous Auralex Studiofoam panels placed around the room. All the audio equipment is located in a Synergy Twin S30 Salamander audio rack placed about a foot away from and in the middle of the short wall opposite the listening position. Power conditioners are all located on the hardwood floor behind and to the left of the audio rack with the exception of the Audience Ar2p-T0 which is plugged directly into the socket behind the rack.

Review Equipment
Pass Labs XP-10 preamplifier
Aesthetix Calypso preamplifier
Pass Lab XA60.5 mono amplifiers
Monarchy Audio SM70-PRO Amplifiers (two, used as mono blocs)
Von Schweikert VR-35 Export Deluxe Loudspeakers
Martin Logan Sequel II Loudspeakers
Oppo Digital BDP-95 Universal player
Acoustic Revive RPT-4 Ultimate Power Supply Box
Blue Circle Audio Mk III Power Line Conditioners (2)
Loudspeaker Cables: Canare 4S11 bi-wired
Interconnects: Acoustic Revive XLR Balanced cables from preamplifier to amplifier, Monarchy Audio XLR DAB-1 Balanced cables from CD player to preamplifier
Power Cords: Cardas Cross,

Specifications
Pass Labs XP-10 Factory Specifications
Frequency Response: 2 Hz to 60 kHz (-3dB)
Overall Gain: -73dB to +10dB
Volume Steps: 83
Remote: Yes
Inputs: Five
Outputs: Two
Input Impedance: 96 kOhm bal, 48 kOhm single-ended
Output Impedance: 1000 Ohms balanced, 150 Ohms single-ended 
CMRR: -60dB, 1kHz
Cross-Talk: -90dB, 1kHz Ref 1V
Signal to Noise Ratio: <-110dB, Ref 5V
Power Consumption: 10 watts
Dimension: 17" x 12" x 4" (WxDxH)
Weight:  20 lbs.
Warranty: Limited 3-year warranty
Price: $5250

Pass Labs XA60.5 Mono Amplifier Specifications
Power Output: 60 Watt @ 8 Ohms, 120 Watt @ 4 Ohms
Leaves Class A @ pk Watts: 120
Gain (db) 26
Input Impedance, (K ohms): 30 / 20
Power Consumption (W) 200
Dimensions: 19" x 7" x 19.2" (WxHxD)
Weight: 63 lbs.
Warranty: Limited 3-year warranty
Price: $11,000 (per pair)

Company Information
Pass Laboratories
13395 New Airport Road
Suite G
Auburn, CA 95602

Voice: (530) 878-5350
Fax: (530) 367-2193
E-mail: info@passlabs.com
Website: www.PassLabs.com