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Reviewer: Arvind Kohli - TNT USA
Reviewed: December, 2016

MANUFACTURER'S PUBLISHED DATA
Manufacturer	Pass Labs
MSRP - US market (USD)	$3,800
Frequency Response	Not Specified
Gain	MM: 40dB @ 1KHz (single ended); 46dB @ 1 KHz (balanced) MC: 71dB @ 1 KHz (single ended); 76dB @ 1 KHz (balanced)
Input Impedance	47 K or 1K / 0-650 pF (MM) 5 ohm - 47K ohm (MC)
Output	20V rms Max; Impedance 300Ohms
THD	< .01 % THD @ 1mV MC input < .002 % THD @ 10mV MM input
RIAA curve accuracy	plus/minus .1 dB 20-20 KHz
Dimensions (W x D x H)	17" x 12" x 4"
Weight	25 lbs

Nelson Pass has had one of the most storied careers in high end audio. He first made his mark while at Threshold, where he developed the landmark Stasis series of amplifiers. These designs were later also lisenced for a series of amps for Nakamichi.

Then in 1991 he founded the eponymous Pass Labs. There he again made his mark on the audio scene with a series of power amplifiers that were configured in a single-ended Class A configuration. These were monikered the Aleph series, and had an iconic appearance with vertical heatsinks wrapped around the chassis on all four sides. Both of these series of amplifiers are still highly sought in the used market and command top dollar.

Pass has been making Phono preamplifiers since 1997, and today they offer 2 models. The XP-25 is a two chassis design with one chassis being a power supply and the other housing the electronics and a full compliment of controls on the front panel.

The model under test here is the single chassis XP-15. The front panel is a handsome brushed aluminum face with a single blue LED. The rear panel has an IEC power cord receptacle. Seperate RCA inputs for MM or MC, an RCA and XLR pair of output jacks. Two sets of jumpers per channel, one for gain and one for loading. There even is a diagram for jumper settings silk screened on the back, very handy. Gain ranges from 41dB to 71dB via the RCA jacks, and 46dB to 76dB via the XLR jacks - sufficient to handle any cartridge I have heard of.

Listening

All but the first test were done using the Ortofon MC Quintet Black. Comparisons were done against the previously reviewed PS Audio NuWave Phono (MSRP $1,899 USD), and the Lehmann Audio Black Cube SE Phono (MSRP $$1,149 USD). The tests have mostly been covered in the Lehmann Audio review, but repeated here for convenience.

"Belen Belen" (Claudia Gomez; Salamandra; Clarity; CNB 1002)
This minimalist recording is a pressed on 180g single sided LPs, and is a great showcase for female vocals and several acoustic instruments. This was the only test done with the Ortofon 2M Blue.

The Lehmann Audio had the noisiest background of all the stages tested here. The PS Audio seemed to throw the widest soundstage, but dynamics and realism on vocals was less than the with the Lehmann. The Pass XP-15 had the quietest background, and great separation of notes of all the stages tested here. But the presentation of female vocals not as lively as the Lehmann. The Pass also presented great detail and layers.

"Rag Hemant" (Ali Akbar Khan, Indian Architexture; Water Lily Acoustics; WLA-ES-20-SACD)
I use this track to examine the upper mid-range and treble regions, represented by the Tanpura and the Sarod respectively.

The PS Audio NuWave Phono [set at 66dB,60ohm] was very involving. The ornamentations on the notes added by the Ustad were vivid, and overall it seemed like there was a three dimensional presentation. The sympathetic strings were audible but was lacking detail and vividness when compared to the Pass and the Lehmann.

The Lehmann Audio [set at 66dB, 100ohm] was a big leap up from the PS Audio, the plucks of each note were now distinctly palpable, and the transient response was simply incredible. This was the kind of presentation, where I was glad to be done with note taking and then found myself indulging in just listening to the music. The Lehmann had a bit noisier background than Pass Labs, but the Lehmann had a much livelier sound. Also, with the Lehmann the sympathetic strings were more distinct and noticeable than any of the other phono stages. The Lehmann Audio definitely delivered my favourite presentation on this track.

The Pass Labs XP-15 [set at 66dB, 100ohm] had the quietest background of the bunch. The presentation was very smooth and liquid, however the transients were not as punchy and palpable as with the Lehmann Audio.

"Blue Rondo A La Turk" (Dave Brubeck Quartet; Time Out; Columbia; CS 8192)
The intro has a lot going on with several instruments and lots of dynamics and transients. The double bass is beautifully played, but sonically speaking this recording of the instrument sounds like a hot mess, barely recognizable as a double bass.

The PS Audio provided a competent of instruments, however the double bass was a bit of a lump of slop.

The Lehmann Audio presented the best separation of instruments of all the units on test. The Lehmann also made it easiest to recognize the double bass as an instrument instead of a lump of bass. In comparison to the other preamps in this test, the Lehmann at times sounded so fast on transients that I actually once checked to make sure the turntable was not spinning at 45 RPM.

The Pass Labs seemed a bit too heavy on the bass frequencies, and the double bass was not as recognizable in comparison to the Lehmann unit. The Pass Labs was overall a more laid back and mellower sound than the Lehmann Audio - mind you that was not lacking in detail, but rather more on the liquid and rich side in contrast to the fast and snappy presentation of the Lehmann. Here is where personal preference comes in, I personally much preferred the Lehmann.

"My bucket's got a hole in it" (Billie & De De Pierce, Jim Robinson's New Orleans Band, Jazz At Preservation Hall 2; Atlantic; SD 1409)
This is a beautiful recording that I use to listen for performance on brass instruments. Lots of dynamics and "in your face" bark of the trumpet and trombone.

With the PS Audio the instruments seemed more distant when compared to Lehmann, not as in placed further back on a soundstage but as in lacking a layer of vividness and detail.

The Lehmann Audio presented the bite of the brass instruments completely unmitigated, not additionally harsh, but brass instruments inherently have an aggressive sound and the Lehmann Audio was not shaving off any of the natural timbre. Instead I ended up lowering the volume a bit to take the edge off, I'd say the Lehmann presents things as is and the Pass Labs in contrast is a bit more forgiving. I very much enjoyed and prefer the Lehmann's unapologetic and candid delivery.

The Pass Labs really shone on this track, the inherent bite and brazen sounds of the trumpet and trombone were presented with a bit of smoothness and liquidity, but absolutely without losing any detail. I felt I could listen to this track at slightly higher levels, if I desired, on the Pass compared to the Lehmann.

"Aria and Corrente" (Andres Segovia - Girolamo Frescobaldi; An evening with Andres Segovia; Decca; DL9733)
I use this track to dissect the tonality of a solo acoustic guitar, with plenty of micro dynamics and soft passages. Also, this copy is very very worn and is also used to inspect the playback of surface noise.

The PS Audio presented plenty of detail, but could not match the Lehmann here. The Lehmann extracted as much life as could possibly from this old, worn and noisy copy. As on previous tests, I was glad to be done with the critical listening and note taking and then could indulge in listening to the album for pleasure. The Lehmann most made me want to just listen to music.

As I had suspected, on a mellow sounding track the mellow nature of the Pass Labs rendered a sound that was just a bit too subdued. The Lehmann was my strongest preference on this track as well, and by a considerable margin.

"Shamas-ud-doha" (Nusrat Ali Fateh Khan; Shahen-Shah; Real World; 91300-1)
A fantastic recording of the master and his troupe. The soundstage is uncanny, and the dynamics and naturaless make this album a favourite of mine.

The Lehmann again shone on this track, it even had better defined instruments and dynamics than the Pass Labs [66dB and 76dB gain], but the harmonium was a bit sharp at times as the instrument can be. The question one would have to parse when choosing between the sonics of the Lehmann and the Pass Labs is - do you want candid fidelity or a polished presentation that mitigates harshness. I prefer the former, but don't claim it is superior to the latter.

With the Pass Labs, instruments and the stage popped out a lot more at the gain set at 76dB than 66dB. However at either setting sharp instruments like the harmonium were a bit rounded and mellowed, especially when compared to the Lehmann.

Conclusion

This listening test more than ever has reinforced the notion that often in life there isn't one model of perfection, but instead there are several flavours that approximate perfection and from among them you have to choose your totem.

That lesson was reinforced here in the comparison between the Lehmann Audio Black Cube SE and the Pass Labs XP-15. The former was more bent towards revealing and unmitigated, while the Pass had a much more liquid and smoother sound. As you see from the above notes, they each played out ahead depending on the programme at hand. I personally overall preferred the Lehmann approach. But I strongly suggest that you listen to both and choose according to your preference.

REFERENCE GEAR
Gear	Manufacturer and Model
Digital Disc Players	• Denon DVD-3910 with Underwood mods (level2 + masterclock) • Pioneer 414
Phono Cartridge	• Ortofon MC Quintet Black • Ortofon 2M Blue(MM) • MusicHall Mojo(MM) • Goldring Elite(MC) • Audio Technica OC9 MLII(MC)
Turntable	• Technics/KAB SL1200 MkII, with tonearm damper
Phono stage	• Lehmann Audio Black Cube SE Phono
Pre Amplifier	• Promitheus Audio Reference TVC
Power Amplifiers	• Monarchy Audio SM-70 Pro, in monoblock configuration.
Integrated Amplifier	• TBI Millenia
Speakers	• Quad ESL 988 • Dynaudio Contour 1.3 MkII • Triangle Electroacoustique Titus 202
Subwoofers	• ACI Force • Velodyne F1500R
Headphone Amplifier	• Practical Devices XM3
Headphones	• Stax SR-40, with SRD-4 adaptor • AKG K701
Connectors	• Various

© Copyright 2016 Arvind Kohli - arvind@tnt-audio.com - www.tnt-audio.com

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