30,000¥ Japan-only updated version of the L-570 bestseller.
Also part of the first units made by Azden for Lux before the switch of the entire production from Alps to Azden.
Partly redesigned circuit boards, newer i/o relays placed (even) closer to the actual terminals and switching both gnd and hot sides of the signals, bigger speaker terminals, redesigned constant voltage circuit, more dynamic power-supply/transformer, a general upgrade in capacitors with non-magnetic items, gold-plated tops, copper foil styrene, pure focus, and even purer PC-OCC copper wiring.
The rest is entirely the same : attenuator, Heat-Pipe, chassis, five-point FRP base and even specifications ; visually, the X's is entirely identical to the original L-570.
Of the three versions, the X's is the rare one : japanese audiophiles in late 1992 were still willing to go the full-tilt 500,000¥ boogie and many bought the ultimate L-570Z's - the real upgrade.
The X's circuit and hardware were reused in the later L-580 for the-same-with-a-newer-look.
A real 570X's here.