Luxman M-05 power amplifier

Japanese audiophiles venerate American high-end audio components, paying huge sums for vintage Marantz tube amplifiers, racks of Levinson ML-2s, and early Audio Research tube preamplifiers. The balance of trade, at the high end anyway, hasn't been reciprocated: Japanese high-end amplifiers and preamplifiers have not received as positive a reception in the US. Perhaps it was a matter of styling, but the sonics of the Sony Esprit line and the class-A Stax amplifiers did not receive the following they might have, had the products been American.

In the past five years, a number of Japanese mid-fi companies have quietly introduced a few high-end electronic prototypes to American reviewers for comment. These amplifiers and preamps embody many of the features found in the better-sounding Krells, Audio Research, and Levinson products, such as dual-mono chassis, polypropylene coupling capacitors, and high-current, class-A amplifier output stages.

The Luxman M-05 is just such a design. Relatively large and heavy for a nominally rated 105W/channel amp, the M-05 is essentially two mono amplifiers on one chassis: two power supplies each with its own toroidal transformer, dual controls, and even two line cords! The class-A circuitry utilizes Luxman's proprietary Duo-Beta/S design, a circuit approach that features minimal negative feedback and wide bandwidth. The single chassis is sturdily constructed with a frame of aluminum extrusions. Large internal heatsinks are cooled by multi-speed fans that can be turned down, but not off. OFC wiring, copper-clad isolation compartments, nonmagnetic materials, and star grounding techniques are all claimed by the manufacturer to enhance performance. Hand assembly is employed for the output stage.

The speaker terminals employ large plastic screw clamps for a very tight fit, but unfortunately their terminals don't easily accommodate the spade lugs found on thicker audiophile cables. Luxman has supplied the rear panel with single-plug jacks as alternatives for these large-knobbed speaker terminals.

The external styling of the M-05 does not follow the "minimalist," bare-bones design of the American high end. The external trim rivals the Czar's crown: gold on gold with platinum accents and silver highlights, offset with cut crystal for the meter windows. The Luxman's front panel is a collage of special anodizing dyes, reminiscent of the striking rose-gold front panel of Barry Streets' latest amplifier. A brushed gold rear panel frames the mixed platinum and gold subpanel extrusion. The square pushbuttons are set in a dark gold, and have been created by forming a dark gold sheet over a clear plastic base; when the control is activated, the rear-panel light shines through. The power switch has a silver-gray coloration. No handles are used on the front panel, perhaps because they might disturb the elaborate jeweled styling. Handles can be found at chassis rear, which is unfortunately not helpful in picking up an amplifier that has its weight concentrated in the front. This makes the M-05 very awkward to move around—one carries it with the cut-crystal meter windows facing down toward the floor.

Speaking of styling, this amplifier just has too many controls for the type of high-end market it is targeted for. Loads of external features are suspect in a high-end product. American audiophiles often equate amplifier quality with chassis weight, clean lines, and a single power switch, not the variety of noble metals decorating the M-05's fascia. Controls abound, both front panel and rear. Take, for example, the two large analog meters, each complete with separate rotary attenuators, and "meter-off" and "peak hold" square push-buttons. These touches give the amp a cluttered appearance I associate with lower-priced receivers, not a $3000 amplifier.

A brief internal inspection revealed excellent workmanship and top-grade components. Gallium arsenide LEDs are used to bias the output stages—an LED drops a pretty constant voltage when it's fired up—which Luxman claims are more desirable in this application, but must be inserted onto the pc boards by hand.

On the Test Bench
The M-05 was tested by Dave Clark of DLC Design. The amplifier delivered a minimum of 120 watts into 8 ohms and 210 watts into 4, virtually matching the specification. There was almost no evidence of "sticking" at clipping, which is an amplifier's tendency to continue clipping after the input signal has fallen back below the level which normally makes it clip.

The amplifier's large signal response to 20kHz squarewaves, driving an 8ohm load, was excellent, with minimal overshoot on the leading edge and no rounding on the trailing edge. These were well within 10% of the squarewave's period, indicating artifacts only above 100kHz, which is excellent performance.

Sound Quality
The M-05's sonics are in keeping with its test-bench behavior. The unit has exemplary highs, and very good midrange. The overall timbre is extended and a bit distant, with a slightly "recessed" sound in terms of dynamics and tonal balance. This sonic profile produces a clean sound, low in listener fatigue.

The bass and midrange are very neutral and unobtrusive. At first listening, bass appears to be lacking, but the amplifier produces deep bass when the music calls for it. Low-frequency definition is more than adequate, but retains the "cool" character of the amp's upper registers. For this reason, some audiophiles may not be tempted to trade in their tube amplifiers for the Luxman M-05's accurate but subdued sonic texture. Its clipping performance, when delivering high sound levels, is smooth, with a subtle loss of detail and mild compression. There was certainly no hashiness, static, or severe distortion.

I have found that dual-mono amplifiers built on two separate chassis often produce imaging and soundstaging that is remarkably exciting, wide, and deep. The M-05 does not "open up" the sound in this manner; it has a natural dimensionality that may be truer to the music. The M-05 does not act like an "expander," so those interested in following the sound of locomotives crossing through their living rooms should try a different product.

The M-05 strives for control, not drama. It clearly is a product that should mate well with voltage-sensitive electrostatics, such as the Quad ESL-63. On my Snell A/Type 3, the amp's coolness and closed-down soundstage did not work as well as other dual mono amps. It did not seem to play as loud as the Levinson ML-9 (an underrated 100W amplifier if there ever was one), but "coasted along" like my "old" Threshold Stasis 3 amplifier, which also strived for smoothness rather than punchiness.

Compared with other amplifiers in the $2500–$3000 range, however, it does less well than the competition. The Classé Audio DR-3 is more dynamic, more detailed, and does a better job of revealing instrumental resonance. The Conrad Johnson tube amps have a far more pleasing midrange presence, as does the Audio Research D-115.

Summing Up
Luxman has given the M-05 hand-built internal circuitry, accurate sonics, class-A operation, and dual-mono design—all signs that this moderate-sized Japanese manufacturer has taken the American high-end market seriously. Yet the cool, closed-down sonics and the amp's overblown exterior mean that more has to be done before American Audiophiles will set aside their C-J, Krell, and Audio Research amps.

Luxman Corporation
US distributor: Luxman America Inc.
27 Kent Street, Unit 122
Ballston Spa, NY 12020
(518) 261-6464

Herb Reichert's picture

no measurements?

John Atkinson's picture
This was 32 years ago, Herb, from my very first issue.

John Atkinson
Editor, Stereophile

Bogolu Haranath's picture

The price for Adcom GFA-555 power amplifier in 1985 was $600 ........... for price comparison :-) .............

Adcom GFA-555 was very favorably reviewed by Stereophile and many other audio magazines ...... Rumor was Nelson Pass designed GFA-555 :-) ............

Bogolu Haranath's picture

DJIA closed at 1895.95 in Dec 1986 ............... DJIA is more than 25,000 now :-) .............