Pros: Speed, power, clarity, size
Cons: Price tag
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.