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Pass Labs X260.5 Class AB monoblock amplifiers review

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The sound

The overall flavor of the sound of the Pass Labs X260.5 monoblocks is fairly-well stated in the company’s literature. They state that their products have “warmth, sweetness, depth and space, that are the hallmarks of fine audio products”. I feel that the sound leans towards the slightly-warm and musical side of the spectrum, rather than the typical solid-state “clear, clean” type of sound. Nelson Pass has been quoted as saying the following regarding his products, I’m paraphrasing, “The sound of tubes, without the hassle”. I have several tube components, and in general Nelson is right, tubes can be a hassle, and expensive too.

The sound that the Pass Labs produce is very easy to listen to, and has good density, the kind of sound that has “mass” to the music. The tonality is more of a “bottom-up” type of sound. This is a phrase that has been used in audio circles to describe the sound of some products. A bottom-up type of sound, is one where the focus and emphasis is from the bass and mid-bass and flows up from that. The X260.5 fits into this type of sound. At the other end of this spectrum, is the “top-down” kind of sound, where the focus and emphasis starts at the treble and upper-midrange, and flows down from there. This latter type of sound is classic of bipolar solid-state, at least historically. While some other solid-state amplifiers can sound clean, clear, sharp, transparent, if this is taken too far, they can often sound analytical, clinical, hard and edgy. The Pass Labs X260.5 monoblocks are not amplifiers like these. They are warm, musical, easy to listen to, have a great density and solidity about them, and they are a touch (just a touch), on the soft side of neutral, versus the clear, detailed and transparent variety, that I’ve heard from other amplifiers.

In my experience, this warm, softer type of sound is characteristic of amplifiers that are built using MOSFET devices. In the past, I have had several amplifiers that use MOSFET’s, namely the Counterpoint Solid 2A amplifier, as well as the British Magnum amplifier. And both of them had that warmer, more euphonic type of sound, while in contrast, amplifiers that use bipolar devices, tend to sound more to the clearer, cleaner, transparent type of sound, the top-down kind a sound that I described above. Most of the transistor amplifiers that I’ve had over the years, tended to sound like the latter.

The current amplifiers that I’m using, the Denon POA-6600 monoblocks, definitely fall in this top-down camp. My Denons have had some upgrades, done by myself. I have installed Cardas copper binding posts, have added a Furutech copper IEC power socket, soldered just about all the interior wiring and hard wired the power cabling inside the amp, eliminating the lousy switchable voltage selector. All these upgrades improved the sound of the amplifier greatly. The Denon’s are rated at 250 W into 8 ohms and are a zero feedback design.

Just a warning for those of you that are auditioning the X260.5 amplifiers, before break-in, the sound is a little bright, with the music not having enough body, “meat on-the bone” type of thing, and they also sound a little restrained. After break-in, the sound gets clearer, with more body and density, more powerful, more relaxed and at the same time, is smoother, and easier to listen to. The soundstage improves, as well. The amps just simply ….. “settles down” and relax.

The bass and sub-bass on the Pass Labs X260.5 amplifier sounds excellent. They are very dynamic and powerful, they sound more powerful than their 260 watts rating would indicate. They had very good control of my MartinLogan Summit X loudspeakers, a speaker which is wonderful, but not the easiest to drive. The X260.5’s had no problem driving my speaker. On Jennifer Warnes’ Famous Blue Raincoat -20th Anniversary 24K Gold Edition” CD, in the song ‘First We Take Manhattan’, the bass and sub-bass on my Denon monoblocks were more defined, more open, clearer and more transparent. However, it was not as powerful and “meaty” as the Pass Labs amps. On Warnes song ‘Bird On A Wire’ on the same album, the bass and sub-bass of my Denon’s was more distinct and detailed, for example. The drums sounded more like skins, however at the cost of a loss of power, dynamics and sheer oomph of the Pass Labs units.

The midrange on the Pass Labs amplifiers was excellent, particularly on vocals, and especially male vocals like Frank Sinatra. In his CD, Sinatra At The Sands, his singing of the song “One For My Baby (And One More For The Road)” is excellent. Through the Pass Labs X260.5 amps, Frank gets the mood and the emotion of the song through unimpeded. He conveys the feelings of loneliness and despair in that song. Another example, this time with female vocals, on the title song ‘Famous Blue Raincoat’, where Jennifer Warnes sings the words “I guess that I miss you, I guess I forgive you, I’m glad that you stood in my way”, the way her emotion and feeling, through these words, were communicated, was simply marvelous. The above words were much easier to follow as well. I had not heard the words, “I guess I forgive you” before, I heard them through the X260.5’s, as well as the emotion and feeling behind them.

The midrange on the Pass Labs X260.5’s was warm, sweet, very melodic and musical. On the modified Denon amps, the midrange was more detailed, for example, on the song ‘Bird On A Wire’, you could pick out the people humming together much easier. This piece was more distinct and easier to hear, sounding more like a number of individuals singing together, and while at the same time, the sound was not as powerful and solid as through the Pass Labs amplifiers. On the Denon amplifiers, you could hear the string section clearer and better focused, from the song ‘Famous Blue Raincoat’.

2 Responses to Pass Labs X260.5 Class AB monoblock amplifiers review

  1. Hans-Peter Schmid says:

    As the owner of a Pass X-350 that I bought in 2003 I can only agree that Pass’ products are made for eternity. Twelve years of trouble free daily use and a sound that I still enjoy as much as on the first day.

    My amp does react to the support I place it on. Mine sits on a sturdy Copulare rack isolated by stacked pairs of Aurios feet. This arrangement opened up the top end and gave me a more relaxed sound from top to bottom, or bottom to top – I have a hard time placing the amp in either camp in the
    context of my system.

  2. becka says:

    a review of the .5 series is so late and irrelevant now that the .8 series is out…. how about catch up?

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