Tube Power Amp Reviews

Unscrewing four Phillips-head fasteners allows the cover to be lifted. From the front, the toroidal AC transformer and printed circuit board (pcb) are positioned at chassis right, while the output tubes and large E-I audio output transformer are on the left. Both transformers employ solder tags, rather than flying leads. This means Woodside can choose better wire; in this case, silver. The tube sockets are not attached to the circuit board. This prevents tube-generated heat from aging the solid-state components, but point-to-point wiring is needed to connect the pcb with the tube sockets. Wires also connect the tube filaments to the toroidal transformer. Ventilation holes surround each of the EL34 output tube sockets, allowing a chimney cooling effect as air is drawn into holes in the bottom base plate, through the chassis vent holes around the tubes, and out the perforated top cover. Overall, this chassis layout shows good attention to detail. Good-quality parts are used. The Woodside's speaker outputs are standard five-way binding posts.

Opening the baseplate, the soldering shows good care, but seems to be handworked, lacking the evenness of solder flow found in wave-soldered products. [Good hand-soldering is more consistently reliable than wave soldering.—Ed.]

Although the MA50's $4495/pair list price is high, 36% of 132 tube amplifiers listed in the October 1993 Audio are more expensive (footnote 4). Two-thirds of the amplifiers rated Class A in Stereophile's "Recommended Components" employ tubes, and all but one cost more than the Woodside MA50. (The average price of the nine top contenders is $6280.)

Listening
My first contact with the Woodside MA50 Renaissances was exciting. They proved to be an excellent match for my Quad ESL-63 USA Monitors, through which the MA50 could be heard to have the traditional strength of Radford amplifiers—lots of spaciousness. The MA50s produced a most convincing three-dimensional woodwind sound; the ESL-63s produced an effortless, wide-open upper register with ample depth of imaging. Two orchestral selections on LP had a palpable sense of the hall: excerpts from Prokofiev's Romeo and Juliet (Erich Leinsdorf/LAPO, Sheffield Lab 8), and Shostakovich's Symphony 6 (Leopold Stokowski/CSO, RCA LSC-3133).

The openness in the treble produced by the marriage of Woodsides and Quads was reminiscent of two of my favorite amplifier/speaker combinations: the older Quad loudspeaker driven by Mark Levinson ML-2s, and the newer Quad ESL-63s driven by a very-broken-in Mark Levinson No.27.

The MA50 sounded more neutral than I'd expected. I did not hear a lush, rich, warm, buttery sound. Rather, the Woodside delivered a cooler, more distant perspective. It was definitely less harsh in some areas, with none of the "transistory" sound that pentodes can produce, although I would not go so far as to call the MA50 "sweet." This lack of harshness was easiest to hear when compared to the Mark Levinson No.27.5 playing CDs. The vocal timbre and "naturalness" of Harry Connick, Jr.'s "I Don't Get Around Much Anymore," from the When Harry Met Sally... soundtrack (Columbia CK 45319), sounded just right through the Woodsides. The Mark Levinson's sound, in contrast, was more forward. The Woodsides did sound fuller and more rounded than my solid-state amps. This was heard as a richness of orchestral timbre on woodwinds that was missing in the Krell KSA-250. The Woodside also produced a fuller string and woodwind sound than the Krell.

The Woodsides' soundstage could also be highly focused, if called for. Odetta's rich, deep voice, singing "America the Beautiful" on Strike a Deep Chord (Justice) was rendered perfectly, centered well between the Totems, well differentiated from the string bass, brushed drums, and piano. Other female vocal selections were just as focused, with no sign of exaggerated size or phase distortions. Maggie Doyle's voice was correctly dimensioned, despite lots of reverberation, on the Patriot Games soundtrack (RCA 07863-66051-2).

The Woodside MA50s did a good job of resolving detail. Driving the little Totems, the Woodsides delivered low-level detail aplenty. Driving Snell B minors, the Woodsides could sustain the deep growl of the organ pedals in Cesar Franck's Chorale No.1 pipe organ solo while maintaining the clarity of the upper registers (Marcel Dupré, Mercury Living Presence 434 311-2). Playing the "Main Title" track from Patriot Games, the mix of flute, Maggie Doyle's soprano voice, and the ponderous 35Hz synthesizer chords were produced cleanly and distinctly. Even when the bass chords predominated, the Snell B minor, driven by the Woodside, was able to sustain a delicate plucked-string sequence being played at the same time.

The Woodsides' bass was clean and detailed. Although it didn't match the solidity of the solid-state amps, it didn't sound anemic. Of course, I didn't expect this 50W tube amplifier to deliver the same quantity of bass as a KSA-250. What it did deliver was convincing. Switching to the My Cousin Vinny soundtrack (Var;gese Sarabande VSD-5364), the Woodside delivered enough bass on Randy Elman's "Something's Wrong" to get my foot tapping, but it lacked the weight and sock of either the Levinson or the Krell. Also, the Woodsides were not as fast as solid-state amps. They could not produce much of a startle from the explosive opening of Terry Dorsey's "Ascent" on Time Warp (Erich Kunzel, Cincinnati Pops, Telarc CD-801). Clearly, both the Krell KSA-250 and the No.27.5 have more bass "slam."

When huge amounts of bass were called for, the solid-state amplifiers did better the Woodsides. Yet the Woodsides erred in the direction of sins of omission; they didn't produce colored sound, just less bass. The No.27.5 remained quick and well-defined driving the Snell B minors with Saint-Sa;dens's Symphony 3 (Marcel Dupré, organ; Paul Paray/Detroit SO, Mercury Living Presence 432 719-2). The stair-step descent of organ notes was heard clearly with the '27.5.

The Woodside's treble response showed none of the darkening or loss of timbre reported by DO for the 1987 amplifier. No "tube editorialization" or other colorations were introduced into Willie Nelson's Across the Borderline CD. All three amplifiers did an excellent job of preserving the quality of separate and harmonized vocal duets, particularly between Willie and Bonnie Raitt ("Getting Over You") and Sinead O'Connor ("Don't Give Up"). The B minors played Prokofiev's Romeo and Juliet, Suites 1 & 2 (Stanislaw Skrowaczewski/Minneapolis SO, Mercury Living Presence 432 004-2) with a transparent, detailed, sweet string tone with considerable depth. This extension was evident on the LP of the Glory soundtrack (Virgin 90531). The width of the hall was evident in the spread and depth of the Boy's Choir of Harlem singing the opening cut, "Call to Arms." The sound of vibes remained detailed, clear, and open, as heard on Joe Beck's "Unspoken Words" (The Journey, DMP CD-481).

Were the Woodsides powerful enough for my big room? Not always. The Chario Academy Ones proved to be too power-hungry. In my big room, these Italian minimonitors drained the British blood right out of the Woodsides. Dan Baird's voice screeched rather than howled in Songs for the Hearing Impaired (Def American 26999-2). Switching to the 175Wpc Classé Fifteen solid-state amplifier solved that problem. When the Charios were used in my smaller listening room, the Woodside amplifiers were quite adequate. Given a dynamic loudspeaker of relatively high sensitivity, like the Snell B minor, the Woodside MA50 can produce spls of 103–105dB at 10'. Then Dan Baird's "Julie and Lucky" strutted with lots of pace, but no strain.

Overall, the listening tests showed that the MA50 represents real progress for Woodside Electronics—just what the DO ordered! The new tube amplifier had resolution, pace, good bass response, and fine soundstage focus. While they weren't as neutral as a Mark Levinson No.27.5, the MA50s did not show the euphonic excesses of the earlier Radford designs. (The MA50 may sound sweeter than either the Krell or Mark Levinson, but only slightly. After all, each of those amplifiers has its own sonic profile: The Mark Levinson has more presence, while the Krell KSA-250 is more distant and dimensional.)

Conclusions
The Woodside design has come a long way since DO's early 1987 report. The MA50s produced a neutral sonic picture with most LPs and CDs, although I did hear some extra fullness to woodwinds and less edginess in string tone on some CDs. They produced a slight fullness and body to the sound. Just as the KSA-250 helps the tonal balance of the Snell B minor, the Woodside MA50s provided a complementary match for the Quad ESL-63. Bass response was accurate, but lacked the power and authority of the Krell KSA-250 amplifier on larger dynamic loudspeakers, which is to be expected. If one uses electrostatic loudspeakers, then the sound of the Woodsides can be detailed, smooth, spacious, and very pleasing.

Overall, the Woodside MA50 Renaissance gets my recommendation, and should be auditioned by those interested in a tube amplifier for electrostatic loudspeakers or sensitive dynamic systems.

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Footnote 4: About one-fifth of the 688 amplifiers listed.