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.