Lehmann Black Cube Linear

Edit: see end for new perspective regarding two things: how it works as a preamp, and how it may be improved with a better power chord
 
Intro: I'm a music-lover, not an audiophile. Relatively new to this hobby. And I haven't extensively tested amps. I do extensive subjective listening tests with what I own, and that's about it. This review is not geared towards professional audio engineers who need to use an amp for long hours and are not trying to 'enjoy' the amp. For such people, this amp might actually be a good choice. I tend to listen many hours a day, too, so that's why I probably won't give up this amp. But I don't find it to be very enjoyable or engaging compared to other power sources with my Beyers.
 
1. It is known that when the BCL came out in 2004 they had been using Sennheiser's then top-of-the line phones to fine tune it.
 
A) Senheisser's HD6x0 series is great, as any visitor to Head-fi can attest through the millions of posts involving them (and the older 580 model). But they have several problems: lack of micro-detail, slow, and flabby bass (650), with highs that can bore some people.
 
B) The BCL is the opposite: tons of detail, fast, tight bass, and really nice extended highs. Most people are amazed when they try the BCL with the older flagship Senns. More recently, some have expressed amazement at first when pairing this with the new-ish 800 and 700 series, however, these are also known to have detail-oriented mids, which over time, can grow old with lack of feeling and character. That's why, from what I've read, a lot of people end up getting a warmer amp than the BCL, or even a high-end tube amp to go with the newer Sennheiser series--the BCL just isn't 'musical' enough for detail-monster headphones.
 
C) Soundstage is precise, but not huge, which is fine for most kinds of music. Noise level is low, which is something to appreciate especially for long listening periods.
 
2. Unfortunately the BCL is not amazing with Beyers, in my opinion.
 
A) because Beyer's already have fast bass, cool mids, and extended, controlled highs. I haven't listened with the T1, but with the DT990 and the DT150 (which is amazing!!) it doesn't really complement the strengths or compensate for the weaknesses of these phones.
 
B) I think if you have phones with really warm mids but need a big more juice up top and down below, this might be worth auditioning. I was blown away at first with how fast and detailed this amp was, but over a few months (about 5, with at least 100 hours of listening each month, mainly on through a HRT HD + external linear power supply source) I have gradually grown out of love with this amp.   
 
The sound is leaning towards the bright side, even though it's not harsh. I would not say it favors upper-mids, as female voices don't sound particularly good in my opinion. It's just rather bright, without being bass-light per se. 
 
C) The bass is interesting, but to me it doesn't have acoustic realism at all. It is tight to a fault. Hip-hop sounds funny, for example. The notes in the low end are clear and you know what they recording studio was trying to do, but it lacks a true visceral impact compared to more powerful amps (even the $99 Schiit Magni, for example). The visceral impact of bass is what makes bass, bass, to me. Even with classical and acoustic jazz (the majority of my music), low end instruments just don't sound as they should. You know what they're playing, but it doesn't sound live, it sounds recorded. Here, with a dark and bassy headphone like the HD650, you're probably going to feel different. You may find that the bass is perfect--and that's why I pointed out that for phones with good bass and sub-bass to begin with (but not ORTHOS!) this amp can provide extra precision and speed. But with phones that have strong, flat bass, or bass that's already pretty tight (like the Senn 700-800 or all the DT Beyers) I think you can do better. And although I've read that this amp is good for Mad Dogs and other efficient Ortho designs, it is still pretty low-powered (I believe 400mw per channel/60 ohms) compared to most newer solid state and tube amps that cater to the present day Ortho wave (i.e., 1.0 Watts per channel/50 Ohms for Schiit Magni 2).
 
Conclusion 1 (before edit): This mixed review could be construed as positive. However, the price of this amp, despite what it can do to noise floor, soundstage, and detail, does not seem to be justified. Especially since most phones really can be driven by lower costing amps, or stereo equipment that you need anyways for your speaker set up. Alas,, Lehmann should get credit for being one of the first really high quality headphone amps that does so much right for the Sennheiser 6x0 series. If you don't have those cans, but if you just really love hearing bright, clean detail all day long, don't care about engaging mids (or have phones with very warm, forward mids), and have an extra $1000 extra to spend on a headphone amp, this could be a good amp for you.
 
Conclusion 2: There are two things I hadn't fully explored, and I am open to the possibility that I will even raise the stars further from 3.5 to now 4.5, once I have a better source and/or better headphones.  A) the truth is it can do interesting things in your larger speaker sound system as a pre-amp. It provides a very fast, clear, and separated sound that can give life to a vintage system like the one I have. It's really amazing how it makes the sound a lot more punchy and extended in the highs and lows. I can see how, though, in very high end speakers, this might be too much of a good thing, which is why most professional reviewers have not commented extensively on it's pre-amp function. B) A Chord Mains Cable really created a blacker background and better sounstage, with more realistic timbres in the mids. This is cool, and shows that the amp can be upgraded for a reasonable amount in my opinion.
 
So, I'm still looking forward to trying this amp with a few more headphone and source combinations to see how much we can squeeze out of it, and perhaps get it up to at least four and half stars. (I'm probably always going to think it was a bit much to pay for a headphone amp! But I'm cheap sometimes.) 

When I told my friends that I had bought a somewhat expensive amp for Headphone listening, and that it had cost more than twice the price of my headphones, they looked at me as if I was sick or confused!
But I keep thinking (after a full year of listening) that it is one piece of equipment that I could very well keep for a loooong time!
My purchase began when I saw it at a local distributor for Sennheiser.  Two months before I had bought my Shure SRH-940's to replace my old Sennheiser HD-280Pro, which had more than 7 years of use.  Reading in several sites about the real task that Headphones impose on the puny headphone amplifier stages in most equipment headphone outputs, and formerly believing that Headphones "should pose little demands" from the driving stage, I was surprised to find such a clear improvment when I first heard this amp.
 
More surprising to me was that the improvment heard from connecting the under $400 USD Shure 940's was very notable and inmediately apparent.  At the store I had a Sennheiser HD-800 at hand and performed a brief but strightforward listening test, using some recordings that I carried with me and that I know very well.  The results were very consistent from every one of the records (CD's and a couple of SACD's).
 
Notable was that the store only had a standard, well used and low priced Sony DVD player, and still with that low-fi player, the sound improvment of the headphones was constant, consistent among the 4 headphones listened to, and inmediately apparent.  No doubts, no numerous replays necessary to confirm anything: the first impressions were solidly heard again and again across the 4 headphones, just in variying degrees but all in the same exact direction.  Notably, these same differences were present across almost all of the recodings I had carried to the store.
 
To summarize my findings, I'll try to resume the impressions in order of importance:
1) More solid, firm and believable sound from the acoustic instruments, specially grand pianos, with more extended and controlled lower frequencies. This was confirmed when hearing different brands of pianos: the unique lows from Bosendorfer Concert Grand 275, due to its additional low strings is unmistakable more clear with all the headphones (my Shure 940, Sennheiser HD 280, and the store's HD 650 and the 800's).  The distinctive sound signature of the several makes of Grand Pianos in the recordings was easier to distinguish even by the non-initiated store employee... after explaining her the differences with a few examples, she was very happily identifying most of them!
2) With good sounding records, the music was more enjoyable, but with some less well recorded ones, the annoyance was augmented.  Now the Shure-940's really start to perform as true Monitoring headphones, ruthlessly exposing less than acceptable recordings.
3) Unexpectedly, the HD-800's sounded less improved than the much less expensive Shure's! in other words: the Shure´s really do benefit disproportionately when driven with the Lehmannaudio BCL.
4) Panoramic image of the sounstage did not widened appreciably, but unmistakably acquired extra depth, retriving a good deal of the acoustical ambiance of the recording studios and specially with the live recordings. (one can bet that it was an empty coke bottle what  is heard clearly falling on the floor of the stage in one LP from Pablo Records in their live recording of a performance by the Benny Carter 4 (8-204 Benny Carter 4 - Montreux '77 Benny Carter (as, tp) Ray Bryant (p) Niels-Henning Orsted Pedersen (b) Jimmie Smith (d); "Montreux Jazz Festival", "Casino De Montreux", Switzerland, July 13, 1977).
5) It is very balanced: nothing is heightened above the rest of the spectrum.
6) Details never heard by me -even with old recordings that I have had and played for many years- started to be heard. This happened with a few of my records and specially with most of my live recordings... even old ones made on cassette recorders many years back!
7) It is very well constructed with best quality materials and components, the volume potentiometer by Alps has a silky, extremely smooth quality, as the 1/4" jacks. The circuit board is also of top quality (I didn't resist the temptation to open it to take a look at it's interior!) Judged by its appearance, it should be very durable, but as I have no idea about the lead free solder used in Europe, I refrain to warrat it.
8) once at home, I retrieved a pair of very old Sennheiser phones: the 414 and 424x from the 70's, that are on the low sensitivity side as both are 600 ohm units.  While they are not returning to active life for sure, they were driven to just acceptable levels by the Lehmannaudio BCL, albeit with the volume control close to maximum and at the high level position of the switches under the unit.
 
Overall, a good quality, well built unit that raises the listening experience of even mid price headphones.
 
Maybe the only thing that called my attention, was that the lack of coloration kept me advancing the volume knob a little too much, and it caused me to become uncomfortable after some minutes of listening.  After I noticed I was playing it a little too loud, I found that the proper level is necessary to avoid this effect. Is is not that the Lehmannaudio BCL distorted or lost any clarity, the reason being that listening straight from the headphone output of my CD player (Harman-Kardon CDR-30) produced the apparent sensation that the volume was high, and when removing that layer of distortion by driving the headphones with this amplifier did initially made me to raise the knob a little too high, and since the sound was still very clean, it was starting to hurt my ears making the listening uncomfortable after two minutes or so.  Therefore, watch for this if you happen to fall in this pitfall.  Amclaussen.
 

Using the Lehmann with my Beyerdynamic T1, and the combo is amazing, I had before the Lehmann an headphone amp I though was a good buy, but after I got the Lehmann I really heard how good the T1 is, everything comes at a cost and many perhaps find the Lehmann costly, but if you can afford it I will higly recomend that you try the Lehmann Black Cube.

First of all, my Sennheiser HD 650 never sounded so good and I never thought it could deliver this much bass.
What can I say about the sound of something that's made to be as transparent as possible? With this amp, the sound is most definitely characterized by your source and headphones at it's full potential.

The headphone: Cardased Sennheiser HD650. The player: Oppo BDP-83 via the dedicated stereo outputs using AudioQuest Sidewinder RCA cables. This is basically a mid-fi set-up, the Lehmann Black Cube Linear USB being the most expensive component.
     I mostly listened to SACDs, but have played CDs, BDs, and DVD-Audio. Using the amp’s USB connection, I played MP3 files to test out the DAC.
     I’ve had the Black Cube Linear for more than two months. Have managed to put in about seventy listening hours and about double that in break-in time.
     Does the BCL have a specific “sound signature”? Yes: the sound is hard, solid, direct. It doesn't try to sound euphonic or soften things up. This is not a tubey sounding amp. Matched with the right recording the BCL can convey warmth, but, for me, its distinctive characteristic is the way it attacks the music. The sound is extremely detailed and energetic even at low volumes. I love drums. One thing that the BCL does with consummate skill: attack percussive sounds with astounding energy. Listening to drums on the BCL is a physical delight.
     A recording that I consider one of the most crystal clear I've ever heard is  Lookin' for Love  by Marlena Shaw. It has studio-perfect sonics. The SACD is released by the Eighty-Eight's record label out of Japan. With this recording as my infallible reference, I can say that the BCL has clarified the "darkly veiled" 650 to the brink of total clarity. Shaw's voice is not just in your head; she takes over your brain and entire being. 
     Needless to say, I'm amazed by the way the BCL handles jazz. But what about rock? My test here is the Original Master Recording edition of Surfer Rosa by The Pixies (it's an SACD issued by Mobile Fidelity). There is no doubt that the BCL delivers the speed and intensity necessary to make well recorded rock an overwhelming experience. There is a bad side here, though. Playing The Kinks's live album One for the Road was a pretty uncompelling experience. Instead of allowing me to get lost in the music, the BCL-650 combo was showing up all its weaknesses. The most impressive thing was how well the amp conveyed the intensity of the crowd, which I could feel surging against my ears.
     In terms of classical music, the BCL can easily keep up with an orchestra careening at full tilt . The headstage often sounds too narrow, though, but that's probably the fault of the 650 rather than the amp. On the plus side, sparkle. The amp got rid of the well known “dark veil” while still keeping the sound relatively warm.
     When you connect the USB to your computer, the BCL begins clicking. The clicks come from inside the box itself. I think it sounds like a relay switch, but I can’t be sure. It’s annoying, but after the BCL warms up the clicks stop. The sound of a piano is much smoother using the Lehmann DAC than it is when I plug my phones directly into my laptop, so the DAC is obviously doing something right. I don’t have much experience with stand alone DACs (for one thing, I rarely listen to music off my computer), so I don’t feel qualified to judge the BCL’s DAC. It doesn’t have a terribly good reputation judging by the comments I’ve read here at headfi. It only accepts 48kHz audio, so no high resolution. The DAC is the lowly Burr-Brown PCM2702E. For what the unit costs, I think the DAC could have been better. On the other hand, the unit was highly commended by the 2009 Sound+Image Awards as an excellent streaming audio product. It is super portable, much more so than the Headroom Micro amp and DAC stack I had (the Micro is small, but has an unwieldy power brick). The BCL itself is small enough to easily fit in a briefcase or book bag. The unit is very easy to take to work. Of course you will need to plug it in once you get there.
     Burn in is a controversial issue. Many people have encountered the phenomenon, but others scoff, claiming that it is physically impossible. I won’t take sides here, but will only describe my experience. When I first turned the amp on, it sounded slow and anemic to me. Very sluggish. Pretty much the opposite of what it sounds to me now. For a while, I also seemed to perceive a slight harshness in the highs, also a little bit of graininess. I no longer perceive that. Whether it is due to burn-in or whether I adjusted to the sound I will leave for you to judge.
     Reports of the BCL getting hot are greatly exaggerated. My unit only gets mildly warm even after being on for hours.
     Features: Two top-of-the-line 1/4" Neutrik headphone jacks with gold plated contacts (the left jack mutes the line out, while the right one can be used in parallel with the line out if you want to listen to headphones and loudspeakers at the same time [the BCL serves as a single source preamp]); four RCA connectors (two inputs and two 60 Ohm outputs) with gold plated contacts and Teflon isolation; one input mini jack for ipod, hardwired in parallel to the RCA input connectors (so I think you can't use both the RCA inputs and the mini jack input at the same time); super smooth ALPS knob; gain switches with four settings (0dB, 10dB, 18dB, 20dB) which allow you to use the BCL with headphones of vastly different impedances; detachable power cord; three color-coded status LEDs; USB input (USB version only; USB cable is included; just connect to your computer and you're ready to go; no driver installation necessary; if you have both the USB and another source connected, the BCL auto-switches to the active source, but if both are active it automatically prioritizes the USB signal; the BCL "simply relays all the system audio from whatever you're doing on the computer, so music, DVDs, bleeped system alerts -- it'll all come out of the BCL if you let it. But that could involve your computer mixing files prior to output, so you'd do well to divert system alerts to the internal computer speakers using Audio/Sound preferences"). 
     Conclusion: I can’t say how the BCL compares to expensive boutique amps, but upgrading from the Micro to the BCL was a mighty leap forward in terms of how well my headphones are performing. There is now more texture to the sound, a lot more movement of air. There is greater depth to the soundstage, but not much more width. The sound is generally fuller. (The instruments seem to have grown in size!) Is this perfect sound? With classical music, no (the 650's headroom is just too narrow for a full orchestra), but with rock and jazz it does begin to approach perfection. Can I imagine an improvement? Sure I can. But that might not be the BCL’s fault. Upgrading my headphones (say to the HD800) and replacing my BDP-83 with the Special Edition (or with the new BDP-95) rather than replacing my amp seems to be the logical path to better sound. The Lehmann Black Cube Linear is not the weak link in this chain.
     Here are a few recordings that sound great to me with the BCL/650:
-Surfer Rosa (Pixies) Original Master Recording SACD from Mobile Fidelity.
-Future Days (Can) SACD.
-Mad 6 (Ravi Coltrane) SACD. Ravi (tenor and soprano sax) is John Coltrane’s talented son. This jazz disc is laden with lots of percussion, making it a huge treat on the Lehmann.
-Getz/Gilberto SACD. This is a bossa nova jazz classic album featuring the hit “The Girl from Ipanema.” It is one of those simply miced, crystal clear analog recordings from the early 60s that give today’s recordings a run for their money. There are some defects: tape hiss, at times one of the singers is pushed way to the far side of the right channel, and, worst of all, a brief but annoying high pitched aberration on the first track (beware). But these problems are minor compared to the overall joy of the sound.
-Love is the Thing (Nat King Cole) SACD from Analogue Productions. In this new remastering, Nat sounds close enough to touch. Corny love songs, but if you want to hear how beautifully the human voice can be reproduced by the BCL in conjunction with the 650, then give it a try. (Beware of the mono tracks.)
-Portrait in Jazz (Bill Evans Trio) SACD. This is a famous jazz album. It’s not my favorite, but, as with the Nat King Cole above, it is a beautiful analogue recording that shows how warm and analogue-like the Lehmann can sound.
-Playing the Angel (Depeche Mode) SACD. A good example of how textured the 650 can sound with electronic music when powered by the BCL.
-Looking for a reference class recording to test how clear a piece of equipment is? Here it is, pure transparency: Lookin' for Love (Marlena Shaw) SACD from the Eighty-Eight's record label. This proves that both the BCL and the HD650 pass with flying colors. Trust me, there will be nothing between you and the music. Now whether you like this kind of music is another matter. It's not my usual thing, but who cares. This disc is almost incomparable for its immediacy and clarity. Marlena's voice takes over your entire head.