Luxman's last really successful integrated ampllifier : even a bestseller in those pre-bubble-bursting days of 1989.
Successful here is meant market-wise : sound-wise, both the L-540 and L-570 were here and there tagged as "reference", "absolute" or "State of the Art", thus topping the already very successful line started two short years before the Alpine days with the L-550 series in 1981.
The L-540 and L-570 are visually identical but for the second pair of speakers and the phones output which the L-570 omits ; inside, they are entirely identical.
The L-570, however, offers 2x 50W in Class A and superlative componentry, a non-resonant composite chassis base, dual copper-plated Heat-Pipe cooling system, a big EI transformer, the STAR grounding circuit, ALPS tone & balance pots, PC-OCC wiring throughout, a superb rosewood case and a 4-gang special attenuator, the latter becoming a Luxman obsession in later years and after Alpine somewhat went.
Said "Ultimate Attenuator" is a big box holding two glass-epoxy PCBs etched with 32 non-magnetic P-shaped gold resistors. In other words, a device like that of the Sony TA-E88B ('76) or the Sansui C-2301 ('84).
The same attenuator is in the L-580, L-500, C-06 / C-06a, CL-38 or C-08.
Feature-wise : the Line Phase Sensor, a processor loop, separate inputs for MM and MC, a balanced input and LUX's typical "tilt" tone compensator.
The L-570 is the sweeter, "slower", of the two : the L-540 is more energetic.
Still to come were the L-500 and the two ultimate versions of the L-570 : L-570X's (may 1992, slightly pricier) and L-570Z's (september 1992, much pricier) which alas were not exported.