Luxman has been around since 1925, which means they've had time to make some genuinely great amplifiers and some genuinely embarrassing ones. The late-seventies stuff — the L-507, the L-480, all that Class A iron — is rightly celebrated. Then came the eighties and nineties, and like a lot of Japanese audio houses, Luxman got a little lost chasing digital and lifestyle products. The renaissance started quietly in the mid-2000s and by 2011, when the L-505uX landed, it was clear they'd found their footing again.
The 505uX isn't trying to be retro. That's the first thing to understand. The casework is warm and gold-accented, yes, but this is a fully modern circuit with a discrete output stage running 100 watts per channel into 8 ohms — stable and confident down into difficult loads. It uses Luxman's ODNF (Only Distortion Negative Feedback) topology, which applies feedback selectively rather than globally, and the difference in listening terms is a kind of tonal ease that most modern amplifiers don't have. Less grain, more air, without the soft focus you get from tubes.
The Soft Clipping Thing
Luxman included a soft clipping circuit on the 505uX, and I want to dwell on this for a second because it gets dismissed as a gimmick by people who've never used it. At moderate listening levels in a real room with real speakers, you occasionally push into clipping on transients. Hard clipping sounds like tearing fabric. Soft clipping rounds the corner and keeps things musical. It was common in the late seventies — Yamaha used it, Luxman used it — and it disappeared as the industry moved toward higher power ratings and nobody wanted to admit their room had limits. Its return here feels like an editorial statement.
The phono stage is the other headline feature, and it earns its billing. Both MM and MC are on board, and the MC input is genuinely LOMC-friendly — you can load it down to 10 ohms, which means a Denon DL-103 or a Shelter 201 will lock right in without an external step-up. Most integrated amplifiers at this price offer MC as an afterthought, some fixed-gain slot that sounds rolled off and nervous. This one doesn't.
There's also a tone control circuit with a proprietary Luxman filter that comes in and out via a physical bypass. The controls themselves are accurate and clean, and the bypass works — engage it and you're listening through nothing but the gain stage. It's the right way to implement tone controls, and it shames the manufacturers who just leave them out entirely.
The transformer-coupled output stage deserves a sentence: it imparts a slight warmth in the upper bass that's not inaccurate so much as flattering. It makes orchestral recordings breathe. It makes acoustic guitars sound like wood.
The honest caveat is this: the 505uX has a house sound, and it leans romantic. If you're running ruthlessly revealing speakers and want a neutral truth-teller, this isn't it. The ODNF circuit does have a character — slightly lush, slightly round on top — and you will hear it. Some people call that a flaw. I call it a personality.
The uX designation marks the updated version over the earlier 505u, with improved output transistors and a revised ODNF-3.5 implementation. They're both good. The uX is better. Don't let anyone tell you otherwise.
A hundred watts, a genuine phono stage, soft clipping, tone controls done right, and Luxman build quality — the kind where the volume knob feels like a bank vault and the binding posts could anchor a boat. For twelve to eighteen hundred dollars used, the 505uX is one of the sanest purchases in vintage-adjacent audio.