LUXMAN 5C50

Commentary

Stereo DC preamplifier of laboratory reference series.

The 5C50 consists of two stages, an equalizer stage and a flat amplifier stage, and uses the same circuit configuration.
In addition to improving the bare characteristics before applying NFB, nonlinear distortion that does not appear in simple continuous wave measurement is eliminated. Furthermore, by adopting a DC amplifier configuration, faithful amplification to the program source is made possible.

DC drift due to changes in external conditions such as temperature is a problem with DC amplifiers.
In order to solve this problem, the 5C50 has developed and adopted an FET with less noise and a large forward transfer admittance (Gm), and with a well-balanced balance between both units. This FET is used to construct a first stage differential amplifier circuit, and DC drift is suppressed by effectively combining cascode circuits, current mirror circuits, constant current circuits, etc.
In addition, we have developed a Dual Monolithical Linear-Integrated Circuit (DML-IC) that blocks all of these circuits to isolate them from the outside and reduce DC drift. The 5C50 uses DML-02, which was developed for a preamplifier.

The subsonic filter uses a variable dip type subsonic filter based on a twin T-type filter circuit. This filter effectively removes ultra-low frequency noise from 5 Hz to 10 Hz without affecting the audible frequency band as much as possible.

The high-cut filter uses an NF type filter with attenuation characteristics of -12dB/oct. to eliminate unnecessary high-frequency noise without affecting the audible frequency band as much as possible.

Equipped with functions such as 2-channel tape monitor function, tape dubbing function, attenuator with preset and Phono input impedance adjustment.

The general tone control function is omitted, and it is equipped with LUX's own linear equalizer for active compensation of program source.

A stable DC amplifier is realized by the use of semi-fixed VR and resistors with excellent temperature characteristics and low noise, as well as silbird mica type capacitors with excellent high-frequency characteristics.

It uses a newly developed lever switch that is highly reliable and comfortable to the touch, as well as a precision-class detent volume with less left-right tracking error.

In the Laboratory Reference Series, in which legs are attached to the lower part and metal brackets are attached to the upper part, and these are supported by metal supports, so that when the product is stacked, an excessive load is not applied to the product lying below.
In addition, the legs and brackets fit together perfectly so that they do not slip or fall over.

As an optional part sold separately, there was a standard rack mounting bracket of EIA standard.

Model Rating

Type	Control amplifier
Output Voltage / Impedance	Pre out : 1 V (Standard), 18 V or More (Maximum) / 500 Ω Rec out : 150 mV (standard), 18 V or more (maximum) / 500 Ω
Total harmonic distortion factor	Phono1/2 : 0.005% or less (Rec out, 2 v, 20 Hz to 20 kHz) Tuner, Aux : 0.005% or less (Pre out, 2 v, 20 hz to 20 khz)
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1)	Phono1/2 : 0.002% or less (Rec out, 2 V) Tuner, Aux : 0.002% or less (Pre out, 2 v)
Frequency characteristic	Phono1/2 : 20 Hz to 20 kHz ± 0.2 dB Tuner, Aux : 0.5 hz to 200 khz -0.5 db
Input Sensitivity / Impedance (Pre-out, 1 v)	Phono1/2 : 2.5mV/30k Ω ~ 50k Ω ~ 100k Ω (continuously variable) Tuner, Aux : 150mV/50k Ω
SN ratio (IHF-A curve correction, input short)	Phono1/2 : 80 dB or more Tuner, Aux : 100 dB or higher
Input voltage resistance	Phono : 300 mV or more (1 kHz, RMS)
Crosstalk	Phono1/2 : -80dB or less Tuner, Aux : -95dB or less
Subsonic filter	Subsonic freq : 4 hz, 7 hz Dip control : sharp to broad continuously variable
High-cut filter	12Hz/18Hz, -12dB/oct.
Attachment	Linear equalizers (uptilt-2/1, flat, downtilt1/2) Phono Input Impedance Adjustment Tape monitor circuit (2 systems) Tape dubbing circuit Attenuator Socket for MC input transformer
Power consumption	15W
External dimensions	Width 442x Height 101x Depth 400 mm
Weight	8.2kg