Luxman M-600A

Class A Power Amplifier

"The Luxman amp...I don't want to upset collectors or hardcore anachrophiles, but this amp made me think the clock had been turned back 25 years or so and I was listening to a small, genuine Class-A Krell. I remember back then being taught lessons about 50-watters which though they had an extra '0' appended to their power rating.

...But the sheer mass the LUXMAN added to the airplane flying past in the Beatles' 'Back In The USSR" contained bass weight more in keeping with a Blu-ray of Battlestar Galactica: it was as if the M-600A came with a sub. "

For me, however, everything is about the voice, and for this I make no apologies. But its success with Ms. Keys led me to the Judds, whose harmonies on 'Don't Be Cruel' are so clear, finely-meshed and seductive that even the near a capella-ness of the performance doesn't lessen the challenge. The LUXMAN put them in the room. You could hear mother and daughter filling their lungs. "
- excerpt from the C-600f and M-600A review by Ken Kessler in the June 2010 issue of Hi Fi News. Editor's Choice 2010 (HI-FI NEWS highest award)

Trickle down technology from the B1000f
Using trickle down technology from the flagship B-1000f, comes this stereo Class A power-house amplifier, with pure A 30W x 2 per channel, into 8Ω. It is stable driving any loudspeaker, even 2Ω loads, with 120 watts to spare.  Monaural  There is a bridging switch on the rear panel if you need more power & weight to your music. In monaural mode the M-800A delivers 120W into 8Ω or 240W into 2Ω.   While there is no increase in current, the voltage is quadrupled. With so much power on tap, the dynamic swings are amazing.  The improvement in micro-dynamics has to be heard to be believed; tonally fuller, more organic sounding.  

Pure Class A = Pure Music
Because the transistors in a Pure Class-A amplifier are never switched off, there is obviously no crossover distortion (there is no crossover - where one transistor turns off, and the other supplies the load current). Notice the uninterrupted curve above on the right. The amplifier is always fully charged and ready to allow the music flow spontaneously, with a dynamic, fast response time, the music is rich & sweet.

Only Distortion Negative Feedback (ODNF).
Luxman's patented ODNF circuitry has redefined the relationship between music signals and noise and does not use phase compensation or NFB loops in the music signal path, instead it accurately isolates distortion components to cancel them.

Luxman holds many patents for audio engineering, amongst them is the application of Global Negative Feedback to the output stage (1955), which while widely used throughout the audio industry, they no longer use themselves.

Luxman nowadays use a distortion reduction circuit called Only Distortion Negative Feedback (ODNF). This system works by isolating noise & distortion at the output from the music signal and sparingly applying negative feedback to suppress them. Conventional negative feedback systems can have an adverse effect on the music, introducing phase distortion. "The circuit features such an ultra-wide range, ultra- high slew rate and ultra low distortion that it does not use phase compensation for the music signal amplifying circuits." This new technology also ensures that need for a DC servo circuit is alleviated, again improving sound quality.

Output Meters
Luxman have a tradition of having VU meters in all of their solid-state amps & integrated amps , interestingly enough they have updated the monoblocks & stereo amps with a vertical, yellow display bar graph, that can be dimmed or turned off completely. The industrial design has also been modernized with smooth round corners & the heat sinks have been placed inside the chassis.

Custom AC Inlet
In order for an amplifier to multiply the signal cleanly, it first needs to receive clean electrical power. Luxman view the AC input with great concern, just as serious listening tests are applied to the power cables, so too is the AC inlet built to rigorous standards. With the M-800A, the AC inlet starts with high purity brass which subsequently receives a non-magnetic nickel plating and finally gold-plating is administered in order to maintain a low resistance.

Line Phase Sensor
Here is a clever device found on the back of every Luxman powered product. You press the button and it will check the phase of the electricity it is receiving. If the AC outlet in the wall is incorrectly wired, meaning the live and neutral are swapped, a red LED will turn on to warn you. You only need to press it once, when you are installing a product to check that everything is in order. Its a simple mistake, that occurs often, and one that can seriously undermine your listening enjoyment.

Mechanical Grounding & Resonance Control
Mechanical grounding and resonance control are taken very seriously in order to allow the electrical circuits operate at their optimum. The cast iron feet are directly connected to the heavily dampened bottom board in order to minimize vibration being conducted throughout the chassis. Similarly Luxman tune the chassis from a resonance perspective in order maintain pace and rhythm. The fasteners torque settings are carefully measured for the sonic optimum.

JPA-1000 Power Cord
High current, high copper purity, flexible power cord is supplied as standard equipment. Molded connectors will never come loose, nor ever short circuit..

Over Sized Speaker Binding Posts
These over-sized binding posts can be cinched down by hand on some of the large speaker cables without resorting to any hand tools. You will also notice that the wiring configuration when the amplifier is used as a Bridge Tied Load (BTL) monoblock is indicated in parenthesis. In the example below, the Right + channel will be used as the negative output to the speaker, when used as a monoblock.

Rear Panel
Is clearly & intelligentlly laid out. The over -sized speaker binding posts will take both spades or bananas and are easy to tighten down by hand for a secure connection. The Mono switch on the upper left hand side is marked BTL (Bridge-Tied Load). The RJ-11 socket is for remote turn on / off, either from a Luxman control amplifier or from a Home Theater processor.

HI-FI NEWS VERDICT:

"... More than any pre / power pairing I've used of late, these actually sound the most like each other: you'd be hard pressed to suggest that one dominates the other in establishing the character of the performance. So, while both proved fascinating partnered with other makes, they deserve each other to deliver their best. And their best is a marriage of detail and warmth reminiscent of a Krell KSA-50. Truly Delicious..." - excerpt from the C-600f and M-600A review by Ken Kessler in the June 2010 issue of Hi Fi News.