Интегральные усилители — Luxman L-507uXII

The L-507uXII is a Luxman integrated with a moving magnet and moving coil phono input, bass and treble adjustment and separable preamplifier and power sections. It combines the New LECUA 1000 attenuator, a discretely configured buffer circuit shared with the C-900u control amplifier, and the Version 4.0 ODNF feedback circuit, with an output stage built as a 3-parallel push-pull structure.

Key specs that matter

Rated output is 110 W per channel into 8 ohm and 210 W per channel into 4 ohm. Line input sensitivity is 180 mV at 47 kohm, balanced line 180 mV at 55 kohm, and the main input 1.05 V at 47 kohm. The phono input takes 2.5 mV at 47 kohm in MM mode and 0.3 mV at 100 ohm in MC mode. Phono response is 20 Hz to 20 kHz within 0.5 dB, and the line path runs 20 Hz to 100 kHz within -3 dB. Distortion is 0.007% at 1 kHz and 0.08% across 20 Hz to 20 kHz into 8 ohm. Signal to noise reaches 105 dB for line, 91 dB for MM and 75 dB for MC, and the damping factor is 260. The unit measures 440 x 178 x 454 mm and weighs 25.0 kg.

Engineering and use context

The ODNF circuit (Only Distortion Negative Feedback) is the Luxman way of correcting distortion without applying feedback to the whole signal. The LECUA 1000 is a computerized attenuator that moves the volume smoothly and finely in 88 steps. The power supply pairs a large capacity EI-core power transformer with four customized 10,000 uF capacitor blocks. Gradation cast iron insulators under the chassis are used to control vibration. Bass and treble each adjust by 8 dB, at 100 Hz and 10 kHz. The rec output delivers 180 mV and the pre-out 1 V. Power consumption is 350 W in use, 86 W at idle and 0.4 W on standby, with models for 230 V at 50 Hz and 115 V at 60 Hz. The RA-17A remote control and a power cable are supplied. Large-capacity, low resistance speaker relays are connected in parallel, internal wiring uses OFC conductors with spiral wrap shielding on each core, and the second stage of the output circuit is Darlington-connected. LECUA also sets left and right balance, and a headphone output is fitted. Speaker terminals take Y-lugs between 8 mm and 15 mm wide.

Pairing

The MC setting suits moving coil pickups with no outboard step-up. The pre-out can drive an external power amplifier, while the main input lets the power stage work with an outside preamplifier.

Alternatives

The Luxman L-505uXII is the lower model in this series, rated at 100 W into 8 ohm and 150 W into 4 ohm per channel.