Mark Levinson No.26 preamplifier & No.20 monoblock power amplifier JA September 1989 page 2

The 20.5 has two sets of inputs: inverting and non-inverting via Camacs, and a balanced input via a Neutrik XLR socket, offering three modes of operation. If the amp is required to be used unbalanced, a shorting Camac plug (supplied) is inserted into the socket not used to connect the other "half" of the balanced input to ground. The output is via gold-plated Fischer sockets, continuously rated at 50A, which provide a gas-tight connection.

The sound
The listening sessions broke up into two broad periods, broken by a vacation (during which you won't be surprised to learn that the No.20.5s found their way back to Larry's listening room). The first was with the No.20.5s driving the Martin-Logan Sequel IIs, with the Conrad-Johnson Premier Seven preamplifier. 15' lengths of Monster M1000 joined the C-J to the Levinsons, which were positioned next to the speakers and connected with single runs of Madrigal CPC speaker cable. Obviously with this configuration, the 20.5s were being driven in unbalanced fashion. The second set-up consisted of the full Mark Levinson lineup, with a No.25 phono preamplifier, powered by its own PLS-226 supply, connected to the No.26 preamplifier with unbalanced Madrigal HPC interconnect. The No.26 drove the 20.5s in balanced mode via 15' lengths of Madrigal HPC fitted with XLRs. Loudspeakers with this set-up were both Sequel IIs and my regular references, the Celestion SL700s.

Source components consisted of a 1975-vintage Revox A77 to play my own and others' 15ips master tapes, a Linn Sondek/Ekos/Troika setup sitting on a Sound Organisation table to play LPs, and CAL Tempest SE and Barclay Bordeaux CD players. Line-level sources fed the No.26 via 1m lengths of AudioQuest LiveWire Lapis interconnect fitted with Madrigal's phono-Camac adaptors.

First, a note on warm-up. In common with nearly all other high-end products—I say "nearly all" just to protect myself against the fact that if I had said "all," someone, somewhere, would be bound to contradict me—the No.20.5 takes a while to sound its best. Listening to the Kavi Alexander/Apogee recording of Arturo Delmoni playing solo violin music (Water Lily WLA-WS-07), the violin has rather too much of a rosiny edge to its sound when the amplifiers are first turned on, with the image thrust forward a little at the listener. After 30 minutes or so, the violin both acquires a more natural tonal color and moves back in the soundstage to a position just behind the speakers.

Perhaps 90% of the improvement in sound quality occurs in the first 30 minutes, so thankfully, the No.20.5 is not an amplifier that you should leave on all the time. Not only does it consume around 1kW per pair, it does heat up the listening room. During an unbroken spell of very hot weather around the end of June, with outside temperatures in the mid to high 90s, the review pair actually put out enough heat in the height of the day that they turned themselves off. I'm sure that this is a rare occurrence, but it does reinforce the idea that the No.20.5 owner should not restrict air flow around the amps by, say, placing them on a thick-pile carpet. The review pair were sited on MDF Mission Isoplats, with the corners drilled to take spikes, so that the amplifier heatsinks would have plenty of space below them.

You may have read last month my report on how the No.20.5s made all the difference between the Martin-Logan Sequel II producing rather a threadbare sound and one that, while still a little undernourished in the lower midrange, became musically acceptable. Once warmed up, the review pair also drove the Celestions with an authority which I had not heard before. Putting on the Adagietto of the recent Bernstein/VPO Mahler 5 (DG 423 608-2), it was hard to believe that the full-bodied sound was emanating from such minuscule enclosures. The double-bass notes on which the slow string tune and harp arpeggios pivot (footnote 1) were rich enough, even on the Celestions, that the music's essential tension—those who only regard this movement as a piece of syrupy Romanticism are misinformed—communicates intact. And on the Sequels driven by the No.20.5s, it would be hard to imagine how a subwoofer could add anything more.

I recently stated in the magazine that I had yet to hear a commercial CD of Elgar's Dream of Gerontius oratorio that approached the sound that I had captured on a Revox running at 15ips using the Calrec Soundfield microphone. Well, no sooner had that statement been engraved in print for all time than I bought a copy of the new Chandos recording with the LSO conducted by Richard Hickox (CHAN 8641 & 2). Maybe this was one of the first Chandos recordings to be mixed with the new Sony DAE-3000 digital mixer, said to have much less of an editorial effect on the music than the older DAE-1100 that they used. (I almost used to feel that their "Worlds ahead for clarity" slogan was only half right and that it should have added "if you can stand an associated brightness.")

While not a purist recording—I note a central pair of microphones flanked by wide-spaced left and right outrigger mics as well as what appear to be spot mics for the vocal soloists on a liner photo—this CD definitely captures the sense of "being there," which is something I particularly value but is so often lacking from mainstream recordings. And with the No.20.5 both allowing a wealth of small detail to be heard without being unduly spotlit—the way, for example, that Elgar interleaves the two separate SATB choirs in this work—and forcing an authoritative midbass balance from the diminutive Celestions, the music communicates both more forthrightly yet more subtly than when reproduced over "big" high-end speaker systems (within the dynamic limitations of the SL700, however).

Footnote 1: I note that, despite the vast improvement in DG's recent orchestral sound, their engineers were unable to resist the temptation to magnify the size of the harp.—John Atkinson
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