Pros: Transparency, effortlessness, clarity, solid sound and very well built.
Cons: Somewhat pricey, only one output stage.
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.