Integrated Amp Reviews

When I reviewed Luxman's L-509X flagship integrated amplifier, in May 2018, that sleek machine shook me to my vitals. I wrote, "Record after record, the L-509X illuminated every important aspect and area of the recording. It lived and breathed in the air around the notes, consistently creating big, solid, spatially natural images that presented me with a) the roundness and complexity of each instrument, b) a holistic sense of the musicians' intent, c) excellent touch and texture and impact, and d) a unified whole, regardless of musical style or dynamic level." I concluded, "the Luxman L-509X integrated amplifier takes a different path to musical involvement. The L-509X is one of the most intimate-sounding, dynamic, texturally nuanced, truthful purveyors of music of my experience."

Luxman's new flagship integrated, the L-509Z, has the same thick aluminum top plate and steel casework as its forebear and weighs a similarly knee-crushing 64lb. The older L-509X cost $9495; its newer, younger sibling rachets that up to $12,495. The front-panel controls are nearly identical, including those big, eye-catching dual VU meters; except for a new 4.4mm Pentaconn five-conductor mini headphone jack and a mute button, the Z matches the cosmetics of the X to a T. But as in all things, appearances can be deceiving. Even the back panels are doppelgangers. "Design of the L-509Z was a Luxman team effort, with Mr. Masakazu Nagatsuma responsible for overall tonal qualities, Mr. Kunihiko Koki for electronics, and Mr. Takeharu Sato for mechanicals," John Pravel, VP of sales for Luxman America, wrote to me in response to emailed questions.

"The Z-line represents a 'generational update' and upgrade above and beyond the X-Series," Pravel explained. "After a near ten-year period since the introduction of the X-Series, considerable circuit and parts improvements yielded superior sonic results. For example, the L-509X had op-amps and buffers in the preamp section. The L-509Z has a fully discrete LIFES system in the preamp. Z-Series also has a seven-segment LED display, 12V trigger and control terminals, and mid-frequencies (EQ ) adjustment controls." The L-509Z also includes Luxman's "LECUA 1000 computerized attenuator" and "crack-resistant peel coat PCBs," the website states.

Let's go over that list of changes.

"Fully discrete LIFES" is Luxman's new feedback system, replacing the legacy ODNF (Only Distortion Negative Feedback). LIFES stands for Luxman Integrated Feedback Engine System; the L-509Z includes version 1.0, aka LIFES1.0; LIFES is now used in both the L-509Z's preamp and the power amplifier sections. LIFES1.0 aims to reduce the unwanted effects of using negative feedback and is said to lower the S/N ratio and distortion. Distortion is lowered "to less than half of the distortion as compared to ODNF4.0, the final derivation as utilized in the previous X-Series, with S/N improved by 3dB," wrote Pravel.

The L-509X included only bass and treble tone controls, now augmented by that "MIDDLE" dial, which Luxman says is "effective in the vocal and lead instrument frequencies bandwidth." L/R Balance, Subsonic, Mute, Mono, and other front-panel controls also appeared on the L-509X, as did the "Line Straight" button, which bypasses the tone controls for the least signal degradation.

What's LECUA? "LECUA" stands for Luxman Electronically Controlled Ultimate Attenuator. "The L-509Z combines a highly precise rotary encoder with a newly developed weighted rotation mechanism to create the 'LECUA-EX,'" the website states, "which offers even greater reliability and a natural, high-quality operational feel. Eighty-eight fine steps from 0 to 87dB and an acceleration setting for the speed at which the volume knob is rotated and a long press setting for the remote control allows for comfortable and thorough volume control action with minimal degradation in sound quality."

So what about "crack-resistant peel coat PCBs"? On a typical circuit board, a thin, lacquer-like polymer is used as a solder mask to prevent unwanted solder accumulations between closely spaced components and solder pads; the mask also provides some protection to the conducting traces during manufacturing. But the mask, which is permanent, can cause stray capacitance; Luxman says it "can have a smearing effect on audio signals." In Luxman's process, the mask is removable—and is removed, removing the mask-induced stray capacitance. Another interesting thing about the circuit boards is the curvy, swoopy course of those 0.1mm-thick gold traces "utilized for each channel of the L-509Z power amplifier section and in other internal locations"; those curvy traces create "better sound, improved current flow, with lower inductance as compared to PCB traces having 'right-angle' signal path direction changes," Pravel said. All internal wiring is OFC copper, and the last leg, from the output stage to the loudspeaker binding posts, is a copper cable with a 3.5mm² cross-sectional area.

Inside, each channel of the L-509Z's class-AB output stage uses three-stage Darlington bipolar transistors in quadruple-parallel push-pull configuration to deliver 120Wpc into 8 ohms, 220Wpc into 4 ohms—same power output ratings as the L-509X. A new, bespoke, low-loss 600VA EI-core power transformer, with round copper windings and 40,000µF per channel of filter capacitance, features "newly developed, large capacity filter capacitors of a more recent internal construction, like those used in the M-10X power amplifier," Pravel wrote. The L-509Z adds newly developed Toshin and Nippon Chemi-Con capacitors.

The L-509Z includes a higher-specced MM/MC phono section with a "new two-step gain switch to select between high and low MC settings to accommodate a wider range of MC cartridges," the website states. By using the "Pre-Out" or "Main In" connections and a front-panel switch ("Separate") that decouples the preamp and power amp sections, the listener can run the L-509Z's pre and power amp sections as separate, standalone components. Luxman's "beeline" technology ensures the "shortest practical signal path implementation," Pravel explained. "The preamp section is located near the rear input-panel, so signals don't travel the distance to the front panel. From input to output, shortest signal routes are optimized for minimum capacitance."

Twenty-eight sharply sculpted top-panel venting chambers, with honeycomb-mesh protective grids, add to the L-509Z's allure. A chunky, user-friendly aluminum remote add to its functionality.

Just like the L-509X, the amplifier is supported by four large insulator feet made from a cast iron/graphite material, which protect the chassis from external vibrations. "The material density [of the feet] increases from the outside diameter toward the center to counteract and suppress external vibration effects," Pravel wrote.

The L-509Z features a large numerical "seven-segment" LED display, which made reading volume levels a cinch across my small room. The VU meters are illuminated by white LEDs, making them easier on the eyes. The back panel sports four pairs of single-ended (RCA) line inputs and two pairs of balanced (XLR) inputs; the first two RCA inputs are on "original high rigidity terminals." This is "a design borrowed from our flagship C-900u/C-10X preamplifiers," according to Luxman USA head Jeff Sigmund. "These terminals employ a special copper alloy with the conductivity equivalent to copper and the hardness equivalent to brass. They also feature an improved internal structure allowing for better contact with the associated cable, as well as improved oversized termination points where the 509Z's internal wiring connects to the rear of the terminal assembly." Why use only two? On the inside of the rear panel, they take up too much space.

Two preamp outputs and one power-amp input facilitate system configuration including biamping. A classic Luxman hairline finish adorns the amplifier's top panel. The supplied remote control replicates the front-panel options, including power on.

To the lovely, CNC-cut top plate, Luxman adds "blaster-finished" aluminum-alloy front and side panels and powder-coated steel bottom and rear panels. Aluminum-alloy blaster finish, which is also used on the remote, is the "same process used in camera finishes by the likes of Nikon and Canon," Pravel wrote.