Tubes Asylum: REVIEW: EAR/Yoshino V20 Amplifier (Tube) by Adrian

This is one of the most interesting audio products in the past few years, from a well-known maverick designer. It is a tube amplifier using a small signal triode as output tube, yet being able to drive real world loudspeakers. Nowadays, we all too often see me-too products packaged and marketed in a different way, but with little innovation. After reading about this amplifier, I contacted my friend at Walrus Systems in London, and he was very enthusiastic about this amp. So I decided to give it a try. EAR products are not distribured in Hong Kong, and hence I bought it directly in the UK, at a very reasonable price of 2100 GBP.

This integrated amplifier is essentially a power amp with a passive controler section. It allows for 5 line imputs and a high quality volume pot. It only takes SE inputs but is fully differential internally. It has three differential gain stages (12AX7), followed by a 12AU7 driver stage (one per phase) configured as a cathode follower, followed by 10 12AX7 triode sections per phase as output. The grids of the output tubes are biased positive to allow for large voltage swings without current cutoff. The low output resistance of the driver stage allows for grid current to flow without distorting the input signal. The output tubes are wired in the "balanced bridge mode", with both anode and cathode connected to the primary of the OPT. This stage therefore has unity gain but enhanced linearity.
I have been hauling this amp (almost 50 pounds) around to listen to different speakers. Although it can drive any speaker with moderate sensitivity (> 86dB), it really shines driving speakers with high sensitivity and benign impedence (such as my Silverline Sonatinas). I heard the V20 driving the Proac Response 2.5 and the Wilson Benesch Act 1, but dynamics is somewhat compressed with these speakers.
The Sonatinas really sing with the V20. The sound is extremely smooth and sweet, but the clarity is also astounding. Low-level detail is abundant, even at very low listening level, which is important since my wife would not allow me to play music loudly. The soundstage is holographic, with excellent image placement. String instruments and vocal music is especially excellent. My old copy of Beethoven Violin Concerto played by Wolfgang Schneiderhan never sounded so good before. In fact, most of my friends couldn't believe it was a DG recording. Alan Yun (designer of the Sonatina) agreed that the mid-range is outstanding. The frequency extremes are also well-extended, although the lower octaves are tuneful and tight, it lacks the slam of a pentode or ultralinear design.
Here is an amp with a distinct flavor, quite unlike anything else on the market. The closest analogy may be a 300B-based SET, but the V20 has more realistic power output as well as better frequency extension. Fans of classical music, especially of string instrument and vocal music should be more than satisfied by this amplifier.

REVIEW: EAR/Yoshino V20 Amplifier (Tube) Review by Adrian at Audio Asylum