But what really impressed me was the way the EF-6 took big dynamic swells in stride with almost casual ease, as if they were no big deal at all. Part of the beauty of this amp is that it makes handling multiple, complex, intersecting musical lines at high volume levels seem like the easiest and most natural thing in the world—just a walk in the sonic park. The freedom from unwanted edginess, strain, or compression is wonderfully liberating, again pulling listeners into closer contact with the music. Better still, the EF-6 imbues the HE-6 with some of its own relaxed, effortless-sounding sonic persona. Some audio journalists have described the HE-6 headphone as being prone to excess brightness, but in my view what they are really describing is the distressed sound of amps that don’t have adequate power to drive the HE-6 properly. The EF-6 amp, however, has more than adequate power, so that when teamed with the HE-6 the combination sounds extremely detailed, yet surprising smooth—a perfect recipe for naturally expressive sound.
There are, however, moments where the EF-6’s rich-sound yet easygoing sonic persona proves less effective than others. An example would be Musica Nuda’s live cover of the classic Beatles song “Come Together” as captured on Live à FIP [Bonsai Music]. Musica Nuda is an inventive and eclectic pop/jazz duet comprised of Petra Magoni contributing vocals (and free-form vocal embellishments) and Ferruccio Spinetti on amplified acoustic bass (which Spinnetti simultaneously plays as a melodic, rhythm, and at times as a percussion instrument). The net effect of Musica Nuda’s treatment should ideally be a heady mix of potent female vocals, expertly crafted melodic bass lines and grooves, plus unexpected and at time almost otherworldly vocal and percussive bass sounds—all driven forward by an almost palpable, electric energy. I played this track through the EF-6 and Audeze’s superb LCD3 headphones and found that the EF-6 caught all of the richness and textural complexity of the music, but was missing that elusive, three-dimensional sense of electric energy born, I suspect, of the interaction between the two performers and the crowd. As soon as the track was finished, I re-cabled the system and played the same track through the Burson Audio Soloist, again using the Audeze LCD3 ‘phones. While the Soloist’s rendition did not have quite the same quality of effortless power that the EF-6’s did, the Soloist’s superior ability to capture very subtle details and three-dimensional aspects of the sound helped restore the invigorating energy the track really ought to have.
Returning, again, to the EF-6/HE-6 combination, I put on the very demanding “Gnomus” movement of Mussorgsky’s Pictures At An Exhibition as transcribed and performed by organist Jean Gillou [Dorian Recordings]. This track provides a serious bass workout (complete with loud low frequency passages that are richly detailed and nuanced, and that at times plunge to pitches almost below audibility), but also showcases the upper registers and varied voices found near the top end of the pipe organ’s frequency range. It is precisely the sort of track that can cause many headphone amplifiers to stumble, especially if they are attempting to drive the notoriously power-hungry HE-6’s. Yet in this environment the EF-6 positively thrived, making the passage sound almost frighteningly powerful and majestic yet—here’s that word again—at the same time curiously accessible. On this track more than many others, it became clear to me that the EF-6 is rarely if ever is daunted by musical challenges—especially challenges involving complex textures, timbres, and high-potency dynamics. It’s almost as if this amp lives to put challenging music back within our grasp, which is a beautiful thing to experience.