Pros: Sounds marvelous, fast warm up, runs cool, multiple input and outputs, precise volume pot for IEM, big power
Cons: Heavy, not the best K1000 amp but then what is?
LUXMAN P-1u REVIEW:
I just finished spending 2 weeks with the Luxman P-1u headphone amplifier from Todd @ TTVJ and this amp was a pleasure to listen to. I just shipped it back two days ago, but if I didn't already have an Eddie Current ZDT amp then I would have been sorely tempted to try to buy the Luxman which ranks among the best dynamic headphone amps that I have tried. Thanks for the opportunity Todd!
GEAR: I used a Samsung DVD > Synergistic Research active shielded coax cable > PS Audio Perfectwave DAC > anti-cables XLR and RCA IC > Luxman P-1u > HD800 with Locus-Design Hyperion cable. I also used my Macbook Pro as source via optical out > Emotiva and sysconcept.ca optical cable. And I used an Apple 802.11n only Airport Express at 5Ghz to connect to my iTunes library on my iMac (which seems to have no stutters or drop outs). I used the Luxman power cord that came with it, plugged into a simple APC computer UPS which does a good job keeping everything quiet. I'm sad to say that I didn't use my vinyl rig as source because I had to return my Nighthawk in order to pay for a dental implant. My cheap GEMsound phono preamp is not up to the task and doesn't perform well with my Benz Micro ACE Red L moving coil cartridge. It was too much trouble to reinstall my Ortofan Blue MM cart for my current preamp since I plan to either get another nighthawk or a TTVJ phono preamp later. In the photos you'll see that the TT made a good stand for setting up the P-1u.
MUSIC (24/96 only where noted, otherwise 16/44 lossless):
* Diana Krall - Live in Paris
* Peter Asplund - As Knights Concur
* John H. Clarke - Acoustic Guitar (bought off CDBaby.com)
* Nils Lofgren - Acoustic Live
* Tord Gustavsen Trio - "Restored, Returned"
* Esbjorn Svensen Trio - From Gagarin's Point of View
* Mattias Svensson Bill Mays Joe La Barbera - Head up High
* Sara K. - "Hobo" 24/96
* Jack Johnson - In Between Dreams, On and On, and Sleep Through the Static
* Jimmy Cobb Quartet - Jazz in the Key of Blues 24/96
* Shelby Lynn - Just a Little Lovin
* Nancy Bryan - Neon Angel 24/96
* Joel Styzens - Relax Your Ears (bought off CDBaby.com)
* Wendy Sutter - Songs & Poems For Solo Cello
* Bob James Trio - Straight Up 24/96
* Eva Cassidy - Live at Blues Alley, Time after Time
* Ottmar Liebert & Luna Negra - Up Close 24/96
* HDTracks.com - Open Your Ears 24/96
* Bill Evans - Waltz for Debby
* Carla Lother - 100 Lovers 24/96
* Infected Mushroom - B.P. Empire
* Pink Floyd - Animals
* Led Zepelin - Mothership
* Bella Sonus - Enamoured
HEADPHONES: In addition to the re-cabled HE800 above, I tried a wide variety of headphones and IEM with it, including my difficult to drive AKG 600 ohm K240M, K1000 and Smeggy SFI pucks, the easier to drive HD600 with APS V3 cable, HiFiMan HE-5 LE and original HE-5, and my very easy to drive LA7000 and HF-2, along with my very sensitive and low impedance JH13Pro custom IEM with TWag cable. I did not bother to re-install the stock HD800 cable, since it adds some upper mid/treble colorations of the headphone and would make the HD800 an inferior tool for assessing the performance of the P-1u. The HD800, HE-5/5LE, LA7000 and JH13Pro were the best phones for assessing the performance of the P-1u, while the others had some weakness or coloration that rendered them less useful. Nevertheless, the P-1u was able to drive all these headphones well, and there is not another amp in the house that these phones work better with (with the exception of the K1000).
COMPARISONS: I compared the Luxman side by side to my Eddie Current ZDT, maxed Woo WA6 with pseudo dual power supply and Sophia Princess 274b rectifier, ALO Amphora, and Nuforce HDP. After trying four different 12AX7/5751 tubes in the ZDT over the past year, I settled on the Sylvania gold pin 5751 as having the most natural and extended treble while sounding more refined than the stock Mullard re-issue 12AX7. For A/B comparisons I could plug the PWD XLR out into the Luxman and then use the PWD RCA out to feed the other amp, and then listen to two amps with the same source at the same time. This allowed for quick switching between amps using one headphone, after volume matching with my Radio Shack SPL meter. I have also tried the PWD's RCA output into the Luxman and compared that to the XLR input, with little differences in sound quality between the two. Finally, I also tried the Luxman's RCA loop-out into the ZDT and compared it to the RCA loop-out on my Woo WES, and found them to both be quite good in sound quality with little difference from directly out of the PWD.
As per requests, I also compared the Luxman with several dynamic phones to my WES with Stax O2 Mk1; where the HE-5 LE were the closest to Stax in terms of sound signature and soundstage but the HD800 closest in terms of detail and speed. However, the Stax rig gave me all that in one headphone (minus the HD800 soundstage), but with the addition of a bit more bass in return for slightly less but more than adequate max volume.
FEATURES: The Luxman P-1u may at first seem to offer few features or bells and whistles, as it doesn't seem to be loaded up with knobs and buttons, but that is not the case. Like my ZDT it has multiple inputs, but while the ZDT has 3 RCA inputs, the P-1u can accept one RCA and one XLR input which you can switch between. Even though the P-1u doesn't offer a balanced output like the ZDT, having the XLR input is better for when your source only has XLR out (Neko DA100 DAC or some phono preamps for example). The ZDT uses output transformers to convert the signal into a balanced output, but if I want to feed a balanced signal into the ZDT I have to use an external input transformer, which introduces an extra set of interconnects and transformer into the mix.
Both the P-1u and ZDT allow connecting two sets of headphones at the same time, without any reduction in sound quality. However, the P-1u has two 1/4" jacks while the ZDT has one 1/4" and one 4-pin XLR jack. Plugging in two pairs of low impedance phones into either amp did not seem to affect the performance, unlike my Sq Wave XL which used to struggle if one of the two phones was not a high impedance phone.
The ZDT offers an 8-watt speaker output, while the P-1u offers an RCA loop-out instead. The ZDT 8-watt speaker out is quiet enough to be used to drive another amplifier (according to Craig at EC), but I feel it would be dangerous to try that in real life. So the P-1u is more useful for someone with two amps where their source only has one output, and its loop-out could be used to feed a speaker amp since it doesn't drive speakers like the ZDT. The P-1u is more convenient to set up because the PSU is built into the main amp's case, and you don't have to find a place to hide an external PSU box where the umbilical can reach the amplifier like you do with the ZDT.
Finally, I wanted to comment on the quality and function of the volume pot. The P-1u has an extremely precise volume pot for low volume listening using very sensitive low impedance IEM. I could turn the volume down to near inaudible levels and not develop a right or left channel imbalance like with some amps using a lower quality attenuator. My ZDT and WA6 volume pots come very close to the P-1u in this regard, and the Amphora with it's stepped Gold Point is also balanced at the lowest setting, while the HDP has a noticeable channel imbalance when turning the pot below below 9 o'clock, above where listening levels are sometimes louder than desired for listening to music while falling asleep.
IMPRESSIONS: I unpacked the P-1u and was immediately struck by how solid and hefty it was. It seems built like a Mac truck, with a classy feel to the case and knobs. I liked the combination of grey matt case with silver front panel, giving it more contrast. At first I wasn't sure about the gold accent plate with the Luxman name/logo on it, but it grew on me very quickly. Normally I don't go for gold accents, but it didn't turn me off in this case (you'll notice the K240M have a gold accent among silver/black theme).
When I first fired up the Luxman it sounded great right out of the box. I can't say how much of a difference warm-up makes, but I did make it a habit to do any serious listening after it had been running for at least an hour. I did the same with my other tube amps as well. Never during any of the time I used it did the P-1u case become warm. This is in stark contrast to my ZDT which becomes hot enough to cook an egg! I can't use the ZDT in my bedroom during the summer because it heats up the room too much, so I use it in my basement where it's always cool year round.
I listened to the P-1u for the first time with the HD800 and Hyperion cable, and my first thought was how similar it sounded to my ZDT and how it replicated the tube amp's sound via solid state. Over halfway through Nancy Bryan's "neon Angel" in 24/96 hi-res I realized that I had gotten lost in the music and wasn't taking any notes or trying to collect impressions for the review. That was a good sign, and it happened repeatedly over the next two weeks. The P-1u doesn't seem to have any sound or flavor of it's own, and does not have any qualities to the sound signature that make it an amp that would need to be limited to only certain headphones. Like my Perfectwave DAC, I found the P-1u to have a very natural, open and transparent sound, which simply made the gear disappear, leaving just the music and whatever sound the headphones would impart. If I had to attribute a character to the sound, I would say it is warm sounding without any hint of darkness to go along with it.
BASS: String bass was snappy, quick and punchy with a nice clean leading edge to the string pluck and no boomy shadow hanging over the music. It was well defined and crisp, without any signs of "one-note" bass. The bass impact and "oomph" was noticeably above that of my Nuforce HDP and still a little above my WA6 and Amphora, running pretty much on par with my ZDT's bass in quantity as well as quality. Bass extension was very good, and the very deep bass line at the beginning of the first song in Bella Sonus "Enamoured" was quite present and not faded out or reduced.
With loud rock or electronic music the bass did not break up and clip until very high levels that I would never listen to normally. The bass gave a solid foundation to the presence and weight of the instruments, which the WA6 and Amphora strived to achieve but only the P-1u and ZDT could fully attain. I noticed this with just about all my headphones except my K1000. While the P-1u could actually attain useable volume levels with K1000, the ZDT still provided slightly more bass impact and volume with those difficult to drive headphones. I should note that the ZDT itself is still not optimal for driving the K1000, and has never been able to match the Cavalli EHHA or the next step up to my SAC KH1000 amp in driving the K1000 (last October I did an A/B comparison of those 3 amps with K1000).
MIDRANGE: I found the mids to be warm and inviting, vibrant and detailed, and not recessed at all, even with the HE-5 which are not as full sounding as the HE-5 LE. Texture and tone of natural instruments was rich and clear, where with strings you could hear the vibration of the body of the instrument and not biased towards strings and bow like with the HDP. Guitars sounded like they were really there, which caught me off guard a couple of times as I looked up to see if my daughter had wandered into the basement with her guitar. Vocals were handled very well, and I could not ask for better, regardless of female or male vocals. Like with my ZDT, when listening to a piano I had a better sense of the instrument being there in the room and taking up physical space when listening with the P-1u than with the other amps, although the WA6 and Amphora were better than the HDP in this regard as well. The mids of the WA6 and Amphora were more forward than the ZDT or P-1u by a small but noticeable degree.
TREBLE: This is the one area where the P-1u pulled slightly ahead of the ZDT in terms of sound. I found the P-1u treble to sound slightly sweeter and more extended than the ZDT (or WES for that matter), with a more natural ring to cymbals. I do feel that my Woo WA6 has a similar treble to the Luxman, but the rest of the WA6 sound doesn't hold up as well vs the P-1u. The ZDT and WES both have a similar treble character to each other and seem like they have more energy near 10 Khz than the Luxman, while the P-1u seems like it has more energy past the 10 Khz mark. This was slightly supported by test tones from Bink Audio Test CD, but my hearing starts to roll off beginning at 12 Khz and is gone after 16 Khz. Regardless, through the ZDT or WES the sound of the cymbals being hit by the drum stick seemed to be slightly more prominent at the lower treble frequencies than with the P-1u, while the cymbal strikes through the P-1u sounded a little more natural with higher frequency harmonics to my ears. This was a subtle difference and some people might not hear it right away until it was pointed out, as the P-1u and ZDT sounded quite similar in all other areas.
SOUNDSTAGE and DETAIL: The P-1u soundstage size is wonderful, and on par with the ZDT which sounded as big as the Woo WA22 with a balanced source last summer. The lack of a balanced output does not seem to hold back the P-1u at all. Both amps are clearly more spacious, with a deeper soundstage than the WA6 and Amphora which sounded more forward and narrower, although those two still surpassed the Nuforce HDP. All of these amps have great detail; but air, ambience and space when listening to the P-1u and ZDT stood out above the other amps, as a demonstration of their improved micro-detail, decay and dynamic range. Imaging was equally as good, and everything had it's place in the soundstage and headstage, without blending or blurring of instruments. In contrast, with the WA6/Amphora instruments were squeezed closer together, and with the HDP the soundstage was even narrower and compressed in comparison to the others.
POWER and DYNAMICS: The Luxman P-1u is a very powerful headphone amp with the typical headphones, and the gain is set just right for both IEM and full size headphones. With the PWD DAC RCA output as source I would normally listen to the JH13Pro with the volume at 9 o'clock, at 10 o'clock with HD600/800, and at 11 o'clock with HE-5/5 LE. With almost all of my headphones I could play the music louder than I would ever want to on the P-1u without clipping or distortion (like with the ZDT), while with the WA6 I could play the HE-5/5 LE at max volume and still fall 4-6 dB below that of the P-1u or ZDT. The 600 ohm AKG K240M did not present a problem load for the P-1u. Although I might normally listen with the volume knob closer to 1-2 o'clock, I could turn the volume even higher than I'd like and the amp didn't run out of steam. It appears that the P-1u has good voltage swing as well as good current handling ability.
When listening to live recordings and trying to imagine that I was there at the actual performance, both the P-1u and ZDT offered excellent headroom for dynamic passages, even when the volume was set for higher than normal levels during the quiet parts of the performance. However, the K1000 needed the P-1u volume to be closer to 3 o'clock, and I could turn the volume to maximum a 5 o'clock with those and it would still not be uncomfortable to listen. With the K1000 the ZDT seemed to offer an extra 1-2 dB in volume and slightly better bass impact and control, even though the ZDT is also not optimal with the K1000. Neither amp could give me a satisfactory illusion of "being there" with the K1000 like my SAC KH1000 amp can, and that is not even the best K1000 amp out there.
SUMMARY: The Luxman P-1u is a no compromise solid state dynamic headphone amp that is among the best I have ever heard, in my home or at meets. I don't believe in stereotypes when it comes to headphone amps, such as when it comes to describing SS vs tube sound. But for others who do, I'll tell you that the P-1u doesn't sound "solid state" at all, if by solid state one thinks of stiff or brittle, harsh, digital, lifeless or cold. But it does have all the speed, linearity, detail and power one would expect from SS. And it has the warmth and refined euphonic sound that one would expect from a high end tube amp like my ZDT.
With my HD800 the P-1u is very slightly better than my ZDT. The sound signature, detail and soundstage on both amps are almost identical, but the treble in the P-1u is a little bit more natural/sweeter and extended sounding. I have mentioned elsewhere that my Woo WES could use a little more treble extension in comparison to the KGBH SE that I heard at RMAF; so it was interesting to note that the ZDT and WES have a very similar quality of treble, while the P-1u treble reminds more of what I'd heard with the BHSE.
The improvement from the P-1u is not enough to have me entertain selling the ZDT to buy one; but if I didn't already have the ZDT and was looking for a high-end amplifier I'd be more likely to pick the Luxman over the ZDT for many of the reasons I mentioned above, and not just because of the sound (runs cooler, more flexible inputs, loop-out, etc). If I had a pair of Fostex horn speakers like Blutarsky, or still needed to drive a Stax transformer for my Stax O2, then I might stick to my original choice with the ZDT.
ADDENDUM: I want to add that I know it's not really a fair comparison to put a $449 DAC/Amp combo like the HDP up against a $3000 dedicated amp, but it was helpful in providing a contrast that enhanced the differences and more easily showed what the P-1u does better than the average SS amp. And while I like the HDP as a backup or bedroom SS amp, it would never fill the role of the Luxman or ZDT in my main rig. While the HDP wasn't completely embarrassed by the amps costing 2x as much, the Luxman is superior to it in most areas - especially in soundstage or spaciousness, transparency, neutrality and refinement (plus low volume channel balance). The biggest area where the P-1u excelled over the maxed WA6 and Amphora was in soundstage size and depth, where these single ended amps normally kept up with my balanced Sq Wave XL in that area. Additionally, the P-1u also held an advantage in treble extension over the Amphora (ignoring the power differences).