There's a version of this story where Luxman plays it safe. They had the L-507uX, a genuinely excellent integrated, beloved by reviewers, moving off shelves. The smart move was to refresh the cosmetics, maybe bump the specs slightly, and call it a day. Instead, in 2018, they built the L-509X — and the X in that name is doing real work.
The 509X sits at the top of Luxman's integrated line, just below where separates start to make financial sense and just above where you begin wondering if you should have bought the 507 and kept the difference. It's a deliberately uncomfortable position to occupy. Luxman knew that, and they answered with hardware instead of marketing.
What Changed, and Why It Matters
The transformer is bigger. That sounds like a minor detail until you understand that a power supply is basically the nervous system of an amplifier — it sets the ceiling for everything downstream. Luxman went with a larger toroidal here, and you feel it in how the amp handles dynamic swings. Orchestral crescendos, kick drums, the low piano notes that can turn mediocre amps into mush — the 509X just absorbs all of it and stays composed.
The preamp section is where the real engineering story lives, though. Luxman deepened the architecture around their ODNF (Only Distortion Negative Feedback) circuitry, which is their long-running approach to feedback loops — they apply it only to the distortion component of the signal rather than globally. Version 4.0 shows up here, and while that sounds like software versioning, the audible effect is a noise floor so low it almost sounds like absence. You stop hearing the amp and start hearing the recording.
One hundred watts per channel into 8 ohms. Not a big number on paper, but Luxman's watts have always punched well above their class rating. Current delivery is what matters more than raw wattage for most speakers, and this thing has grip. It will drive difficult loads — the planars, the older British speakers with their famously low impedances — without sounding like it's working.
The tone controls are real, by the way. Not an apology. Luxman has always been unapologetic about including a proper bass/treble circuit, and on the 509X it's implemented well enough that engaging it doesn't feel like cheating. More amps should have the courage.
Sonically, the character is warm without being syrupy. There's detail retrieval that competes with solid-state amplifiers at twice the price, but it never tips into the clinical territory where music starts sounding like a demonstration. This is an amp that makes you want to play the next record, and then the one after that.
The honest caveat is the phono stage. It's included, and it's not bad — MM and MC, properly implemented — but for an amplifier at this price point, it's the one place where Luxman didn't go all the way. If vinyl is your primary source, a dedicated phono stage in the $500–$800 range will outperform the built-in stage and take the 509X somewhere noticeably better. That's not a dealbreaker, just a conversation you'll eventually have with yourself.
Build quality is absurd in the best way. The volume knob on the 509X uses Luxman's LECUA electronically controlled attenuator — a motorized, resistor-ladder volume control that eliminates channel imbalance at low levels. You turn it and it feels like operating something in a submarine. Nothing rattles, nothing flexes, nothing feels like value engineering.
Used prices have settled into the $4,500–$6,000 range, which is still real money, but for a reference-grade integrated amplifier that was $9,000 new, it's the kind of deal that makes sense if you think about it long enough. And once you hear one, you'll think about it long enough.