Luxman M-300

The M-300 is one half of the last classic Luxman combo to not see part of its production run go through the Alpine takeover.

Price-wise a step below the C-5000A / M-4000A combo but part of Stereo Sound's "Best Product" section in the winter of 1981 nevertheless.

The M-300 is a big Class A powerhouse holding all the 1980 modern Luxman : Duo-Beta NFb scheme and Plus-X regulation.
Anybody reading TVK since 2005 knows what Duo-Beta and Plus-X are and how they work so I won't repeat the description here - see the TECH 1 section if you don't remember.

Added to those proven technologies was a Line Phase Sensor : a small back bit allowing to see if the AC cord is plugged the right way, in phase. At first implemented with a round button, the production M-300s saw the final, square, design - more in sync with the upcoming 1980s :)
Luxman still has that today and I really wonder why nobody else does.

Also in : four 12,000µF ELNAs, two bigga transformer, film and styrol caps, 500-core OFC shielded wiring, FET inputs, non-ferrous & non-magnetic parts, gold-plated terminals and dual-mono structure with triple push-pull (per side !) of 2SA1215 / 2SC2921 LAPT Sankens stacked on three rows of "sharkfin" heatsinks.

The M-300 can output 2x 42W in Class A or 2x 170W in Class AB ; a front pot allows easy switching and, cherry on the cake, switching either way does not temporarily mute the sound - like a Sony TA-N86B.
Input is dual-differential amp with cascode amps, cascode again in the pre-driver stage, then 1st, 2nd and final stage, the latter three having each its own regulated power supply.

The M-300 however hides all this under luxuriously discrete looks, with or without wood enclosure - better with.


M-300 KA
Rare upgraded version *somewhat* available very late in the day.
Regulation, pre-driver stages, caps, protection circuits, some voltage sources reversed (!), Class A current feeds lowered and output stages were modded but the looks, however, were kept absolutely identical (this is Luxman allright :)
The service manual doesn't mention the serial number after which the 300 became a 300 KA. The "KA" was (supposedly) (theoretically) (wishful thinking) made for all markets.


Depending on market and timeframe, the 300 combo was announced as the "New Laboratory Series" - the second of a long line of befuddling marketing tags with Reference, Laboratory and Standard always present. But not necessarily in that order, Luxman oblige !

Made to be mated with the equally luxurious and equally Class A C-300 amplifier, the M-300 sold very well during a fairly short period of time : barely a year and a half on most markets.