Aspects of recordings I thought I knew well became audible to me for the first time. This is a very fast amplifier, as evidenced by its clean playing of complex passages. Classical and other orchestrated music really comes alive with the Zen. However, as with several SET amplifiers I have listened to, the Zen really excels at reproduction of acoustical instruments and vocals. This amplifier reproduces vocals with rich and complete tonal quality, as good as anything I have listened to in the past, and definitely better than anything else that I have been privileged to audition in its class.
Acoustical instruments sound so rich and natural, they sound as though they are in the same room.
Negative Impressions Three arguably negative aspects of this amplifier actually result from the high quality output and faithful reproduction of the input signal. First, weakness or poor quality of other components in the system now stand out, begging for replacement or revision. For instance, my Conrad Johnson preamp added substantial coloration to the sound, coloration that was previously less evident, and more acceptable. Adding the Zen Triode to a system could cost more money as weak components demand replacement. Lower quality recordings may not sound as good as they do on lesser amps because flaws are no longer masked by the amplifier.