Highlighted User Review

Pass Labs X 150 User Review

MSRP: $ 4000.00
Description:
Gain: 30 db
Frequency response: -0 dB at DC, -3 dB at 100 kHz
Power Output: 150 W maximum @ 1% THD, 1kHz into 8 Ohms (300 W into 4 Ohms)
Maximum Output Voltage: +_ 50V
Maximum Output Current: +_ 20A
Input impedance: 22 kohms balanced
Slew Rate: +_ 50V/uS
Output Noise: 300 uV unweighted 20-20 kHz
Random Noise Floor: approx. 2uV
Dynamic Range: 145 db (random noise floor to peak output)

16 Reviews
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4.88 of 5

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Reviewed by:Jbreezy5 (AudioPhile)
Review Date
September 7, 2009
Overall Rating
5 of 5
Value Rating
5 of 5
Used product for
1 to 3 months

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

Review System:

Preamp: Arcam A75+
Amp: Pass Labs X150
Universal Player: Denon DVD-2910
Cables/Interconnects: Blue Jeans Cable 10 ga. speaker cables w/locking bananas; Interconnects
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 alone. The blue LED’s indicating power/standby are a little annoying, if watching a movie, but can easily be covered (this is the original version w/o current meter). 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 amplifiers; but the Pass worked best in my system.

Also want to thank Mark at Reno Hifi, who sold me the amp; excellent customer service and included 3 free SACDs (to my surprise when I opened the package) w/the purchase and delivery was on-time; included 1 yr warranty.

I don’t know the exact product model year; I believe these began production around year 2000.

-JBreezy5-\


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