Smaller sibling to the bestselling L-550 - also bestseller.
The L-510 has the same circuits as the bigger L-530 but drops in power output, Heat-Pipe and i/o terminals.
The 510 and 530 are, visually, exactly identical : front, back, top and sides. Inside is pretty close, too. The L-550's Heat-Pipe is however replaced by two rows of "sharkfin" heatsinks (anodized black in the L-530, natural in the L-510) and the 300VA EI transformer is a more standard model.
Smoothing caps are two 15,000µF and the output transistors are four p-p of Ring Emitter Transistors (Sanken I believe).
The NFB tone controls and phono cartridge selector also were simplified from the L-550 topper with six turnover frequencies instead of ten (enough to not be an audiophile) and four phono positions instead of six (enough to be an audiophile).
Local NFB loops according to Duo-Beta and power-supply regulation according to Plus-X circuit. Power output is of 2x 8W in Class A, sliding up 2x 100W above that.
The switch from Class A to Class A/B is automatic when higher output levels are required ; the little "warm-up" LED is there to announce when eggs can be fried on the top venting area.
Like the bigger models, the L-510 and L-530 were updated as L-510X and L-530X in late 1983 : adding a DAD input, dropping the 2nd phono input and Class A mode (L-510), refining the componentry with better power transistors, FET-charged inputs (reserved for the MC input only in the original versions), grounding paths (the future STAR circuit, where signal patterns are grouped by current magnitudes and not location) and bigger binding posts.
The top plate venting opening was also redesigned for the L-510X : as the phono section which ran the entire right side's depth was no more, the heatsinks were placed longitudinally instead of running through the depth of the enclosure. To do so, however, the 510X dropped one row of sharkfins...
If the L-510 and L-510X look nearly similar outside, circuit- and structure-wise, they are almost completely different amplifiers.
The ventilation covers were different in and outside Japan : one screwed plate (Japan, as shown here) or six pretty (but fragile) mini-grilles set directly in the wood (export, see here) - either you are Luxman and make things complicated with no real need or you are not :)
The original L-510 / L-530 were made by Lux Corporation in Osaka with a "YOSII" T-tag (1983) ; the L-510X and 530X got T tagged by Alpine in Tokyo (1984).
If I'm not mistaken, the L-510X was an L-525 outside Japan, remaining available as late as 1990 in some european countries alongwith the much bigger L-560 and inheriting its shiny knobs (vs. the semi-matte of all the 1st gen' L-5xx series).
The japanese 510X and 530X however kept their semi-matte knobs - either you are Luxman and make things complicated with no real need... or you are not.
Very solid, good-looking and sweet sounding amps - no wonder Luxman sold so many.
A real L-510 at hifi-do's and a real 510X at hifi-do's as well.