Luxman L 505u (2007–2012)
A high-end integrated amplifier from Luxman's V Series. It uses ODNF2.2 circuitry in a pre-main design.
Overview
The Luxman L 505u is an integrated amplifier (configured as a pre-main amplifier) released in 2007 as part of Luxman's V Series. Luxman marketed it as the "Ultimate edition" of the L-505 series. It builds on technologies developed for the flagship M-6000 power amplifier and C-1000 preamplifier. The phono stage has switchable MM/MC inputs. The tone controls have selectable frequency bending points. The output stage is a dual design that separates class A and class B operations for improved linearity. Production ran until approximately 2012. It came in standard Blaster White and limited champagne Gold finishes, each with an illuminated power meter.
Specifications
| Continuous effective output (8 Ω, 20Hz-20kHz) | 55W + 55W |
| Continuous effective output (4 Ω, 20Hz-20kHz) | 72W + 72W |
| Continuous effective output (8 Ω, 1kHz) | 100W + 100W |
| Continuous effective output (4 Ω, 1kHz) | 140W + 140W |
| Input Line | 4 system |
| Input Phono | 1 System (MM/MC Switching) |
| Input Balance line | 1 system |
| Recording input / output Line | 2 system |
| Pre-output and main input | 1 system each |
| Speaker output | Routes A and B2 |
| Amplifier circuit | ODNF2.2 |
| Output configuration | Bipolar parallel PP |
| Power transformer | EI Type 440 VA |
| Total harmonic distortion factor (8 Ω, 1 kHz) | 0.005% or Less |
| Total harmonic distortion factor (8 Ω, 20 Hz to 20 kHz, 55W) | 0.03% or Less |
| Cross modulation distortion factor | 0.03% or Less (8 Ω, 55W, 60 hz : 7 khz = 4 : 1) |
| Output bandwidth | 5 Hz to 50 kHz -3dB (0.1%) |
| Input Sensitivity / Impedance Phono MM | 2.5mV/47k Ω |
| Input Sensitivity / Impedance Phono MC | 0.3mV/100 Ω |
| Input Sensitivity / Impedance Line | 180mV/42k Ω |
| Input Sensitivity / Impedance Bal. Line | 180mV/79k Ω |
| Input Sensitivity / Impedance Main in | 1V/51k Ω |
| Input Sensitivity / Impedance Phono1 | 2.5mV/30k ~ 50k ~ 100k Ω (continuously variable) |
| Input Sensitivity / Impedance Phono2 | 2.5mV/50k Ω |
| Input Sensitivity / Impedance Tuner, Aux1/2 | 150mV/50k Ω |
| Output voltage Recorder | 180mV |
| Output voltage Pre out | 1V |
| S/N ratio (IHF-A) Phono MM | 91 dB or more |
| S/N ratio (IHF-A) Phono MC | 75 dB or more |
| S/N ratio (IHF-A) Line | 105 dB or more |
| Signal-to-noise ratio Phono1/2 | 62 dB or more |
| Signal-to-noise ratio Tuner, Aux1/2 | 80 dB or more |
| Maximum allowable input Phono | 300 mV or more (RMS, 1 kHz) |
| Residual noise | 0.5 mV or less |
| Frequency characteristic Phono | 20 Hz to 20 kHz ± 0.5 dB |
| Frequency characteristic Line | 20 Hz to 100 kHz + 0 -3.0 dB |
| Damping factor | 110 |
| Tone Control Maximum Change Bass | ± 10 dB (100 Hz) |
| Tone Control Maximum Change Treble | ± 10 dB (10 kHz) |
| Tone control | LUX System NF Type with Bending Point Frequency Switching |
| Low-range bending point | 150 Hz, 300 Hz, 600 Hz, defeat |
| High-frequency curved point | 1.5 kHz, 3 kHz, 6 kHz, Defeat |
| Low-cut | 30 Hz (-6dB/oct.) |
| High Cut | 8 kHz (-6dB/oct.) |
| Low boost | 70Hz(+6dB/oct) |
| Attachment | Input impedance adjustment for Phono1 |
| Attachment | Tape dubbing circuit |
| Attachment | Attenuator (-18dB) |
| Semiconductor used Transistor | 47 |
| Semiconductor used IC | 1 |
| Semiconductor used Diode | 20 pcs |
| Semiconductor used Zener diode | 4 pcs |
| Semiconductor used Varistor | 4 pcs |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 210W (Electrical Appliances and Materials Safety Act) |
| Power consumption | 82W (no signal) |
| Power consumption | 1.2W (standby) |
| Power consumption | 200W (8 Ω, both channel operation, at rated output) |
| External dimensions | Width 467x Height 179x Depth 437 mm |
| Weight | 21.0kg |
Design
The L-505u uses Luxman's ODNF2.2 (Only Distortion Negative Feedback) circuitry, which feeds back only the distortion component. That gives fast slew rates and wide bandwidth. The power supply has a 440 VA EI transformer and Schottky barrier diodes for high-efficiency DC conversion. The main amplifier is a pure complementary OCL system with dual power supplies and a two-stage differential input. An emitter follower circuit isolates the pre-driver and output stages, which stabilizes performance under varying speaker loads. In the preamp section, the phono equalizer uses a class A inverted Darlington push-pull topology, and the tone control is the LUX System NF type with selectable low- and high-frequency bending points. OFC wiring and glass fiber circuit boards are used throughout. The front panel has a switch to separate the power and pre-power sections. The unit has VU meters and comes in Blaster White with blue illumination or limited champagne Gold with yellow illumination.
Context
The L-505u is part of Luxman's V Series and is the fifth generation of the L-505 line, which goes back to the SQ505 of 1968. It uses circuit technologies developed for the M-6000 power amplifier and C-1000 control amplifier. Luxman marketed it as the "Ultimate edition" of the series, designed for reference-level performance with solid-state precision and analog warmth.
Market
The L-505u was originally priced at ¥225,750, and the L-505uX variant retailed at ¥238,000. In the US it carried a retail price of $4,100. Units intended for the US market needed an internal voltage adjustment to run on 120V, including bias calibration. Used units have been listed for sale between $1,950 and $2,500, depending on condition.
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