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I must admit, right from the outset, that I find reviewing electronic components harder than reviewing loudspeakers; the faults are less immediately obvious. No preamplifier, for example, suffers from the frequency-response problems endemic to even good loudspeakers. And power amplifiers? If you were to believe the older generation of engineers—which includes some quite young people!—then we reached a plateau of perfection in amplifier design some time after the Scopes Monkey Trial but well before embarking on the rich and exciting lifestyles afforded us by Reaganomics. (In the UK, it is…
On the left are the two tape-loop controls, one switching between tape loop 1 and tape loop 2, the monitor switch also offering a third "defeat" position where the tape loops are completely out of circuit. An even smaller switch offers the choice between inversion and non-inversion of absolute signal polarity. The "soundstage" controls are to the right, the stereo/mono switch and balance controls, the individual level-adjust controls for each channel offering a maximum swing of ±5dB in detented 1dB steps.
On the rear panel, all inputs and outputs are implemented with unbalanced Camac…
Those familiar with earlier Mark Levinson electronics, where elaborate heatsinking was used on the various modules to ensure that the transistors accurately tracked one another thermally, will find the No.26's interior a surprise. The circuits have been designed not to need the mechanical thermal coupling previously used, resulting in a cleaner-looking layout. Despite the pcb commonality, construction is totally dual-mono, the regulated power supplies being separate for each channel, the board layout also keeping the channels separate—LH channel to the front, RH to the rear. High-quality…
Rather than the ubiquitous 5-way binding post, Madrigal chose to use gold-plated Fischer sockets to connect the loudspeaker. These are rated at 50A continuous, 80A peak, and provide a gas-tight connection. (There is a satisfying "pop" when the plug is removed.) A color-coded pair of plugs is included with each No.20; your ML dealer should be willing to fit these to the cables of your choice, though Madrigal's own CPC cable can come prefitted. To aid changing cables, I used 5-way-to-Fischer adaptors for my tests, but I wouldn't recommend this for a permanent installation.
A matter of…
The second, more common category is that of components which appear neutral but actually have subtle problems which detract from the enjoyment of the music, resulting in cold, rather clinical sounds. Examples which spring to mind are the original PS Audio IV, the West German Burmester, the Klyne SK-5A, the Krell PAM-3, the original British Fidelity MVT, the Meitner, the now-obsolete Meridian 101, Quad's 44, and the Audio Research SP9 (footnote 6). These models are termed "accurate" by many listeners (and their designers, of course), who point out that if the music isn't enjoyable, it is…
Presumably due to its combination of regulated power supply and class-A operation (though such conjecture over the correlation between art and technology is treading on thin ice), the No.20 proved more capable than almost any other amplifier I have used in the ability to "decode" dense musical lines. Take the heavy left-hand block chording in Liszt's B-minor piano sonata (in particular, the superb new Reference Recordings version with Minoru Nojima, RR-25). In the double-speed recapitulation of the triple-time Grandioso theme, Liszt has written 1-3-5 F# triads an octave below the bass clef.…
John Atkinson wrote about the Mark Levinson No.20.5 in September 1989 (Vol.12 No.9):
Some things are down to timing. When Madrigal's Mike Wesley visited Santa Fe just before Christmas 1988 with this revised version of the Mark Levinson No.20 power amplifier that I had reviewed back in Vol.11 No.5, I was in the middle of listening sessions for a number of loudspeaker reviews. I did not wish to insert a radically different power amplifier into my system halfway through those tests. Although I did plan to write a review of the amplifiers, at that time it seemed appropriate, therefore, that…
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.…
It is this ability to convince the listener that there is apparently limitless power in reserve, coupled with a wealth of detail that is presented in a musically natural fashion, that most impresses me about the No.20.5. With lesser, if still worthy, amplification, there is a level of added fuzz that overlays the sound to an extent dependent on absolute level. As the music plays softly, all is well. But as things either get louder or more complicated, individual instrumental or vocal voices start to lose that individuality, the whole starting to blend, much as they do on all but the very…
John Atkinson wrote about the Mark Levinson No.20.6 in April 1992 (Vol.15 No.4):
Madrigal Audio Laboratories launched their first new Mark Levinson product, the No.20 "reference" power amplifier, in 1986. This massive monoblock featured an output stage running in class-A up to 100W into 8 ohms, and full regulation of the output stage voltage rails. When I reviewed it in 1988 (Vol.11 No.5), I thought it one of the finest amplifiers I'd auditioned, particularly regarding soundstaging and low-frequency authority. (Stereophile subsequently bought the review pair!)
Madrigal's thinking…