Audio Database

C5000A
Commentary

The control center was developed for the top-of-the-line audio system by LUX's unique technology such as duo-beta circuit.

In order to improve sound quality, we have adopted LUX's own duo-beta circuit.
In this circuit, the minimum necessary amount of NFB is applied to all bands, and a DC servo circuit is combined.
This eliminates TIM distortion by reducing the amount of NFB by keeping the gain of the amplifier low. In addition, the DC servo circuit not only cuts ultra-low frequency noise, which causes intermodulation distortion, but also uses a low-noise FET amplifier and a high-quality film capacitor in the low-pass filter circuit low-pass reproduction.

In order to realize an amplifier with low gain and good characteristics suitable for a duo-beta circuit, we have adopted a combination of a cascode differential input bootstrap circuit and a transistor dynamic resistance circuit at the input stage.
In the output stage, a four transistor SEPP circuit is used to keep the output impedance low.

In order to minimize wiring, all switches are remotely connected to the board so that the circuit on the board can be directly switched by the knob on the panel. In addition, multi-circuit switches are used in parallel to prevent noise degradation caused by contacts.
In the circuit configuration, the left and right channels are divided into blocks, and each board is separated independently to eliminate mutual interference.
Highly reliable connectors used in communications equipment and other devices are carefully selected employment to the connecting parts of the circuit boards, and gold plating is applied to the terminals on the circuit boards to increase the reliability of the contacts.

The power supply section is equipped with a high-capacity toroidal transformer and a twin monaural high-speed constant-voltage power supply.
For the transformer, a toroidal transformer with low leakage flux and high magnetic efficiency is adopted, and the core size is large enough to be used for a power amplifier of about 25Wx2, which is a common size, so that extra space is provided.

In order to prevent electromagnetic distortion, metal shielding is removed from the opposing surface of the substrate.
In addition, to prevent noise, we use double-sided boards to block the boards and use remote switches to avoid adverse effects caused by wiring. We also use specially ordered switches made of non-magnetic materials for switches.

It uses carefully selected parts with an emphasis on sound quality.
Considering that non-polar film capacitors also have polarity, we have determined the polarity and consciously applied a bias to solve this non-linearity problem. This DC bias generates a Coulomb force between the polarities of the foils inside the film capacitor, and simultaneously prevents mechanical vibration.
The volume is made of conductive plastic in consideration of durability, sound quality and usability.
In addition, the equalizer stage and flat stage, which are essential parts of the pre-amplifier, are made of tantalum nitride, which is the most excellent in performance, after confirmation by trial listening.

For the tone control, it uses the NF type Lux System with a curved point switching.

Equipped with high filter and subsonic filter.
Also, the filter circuit can be bypassed when not in use.

Equipped with socket corresponding to 8000 series booster transformer for MC type cartridge sold separately.
This transformer uses the best materials for the core material and is a toroidal transformer using silver wire and Litz wire for the winding. It has excellent high-frequency characteristics.

Model Rating
Type Duo Beta Circuit Stereo Control Center
Output voltage Pre Out : Standard 1 V, Maximum 20 V (Distortion Factor 0.002% or Less)
Rec Out : Standard 145 mv, Maximum 18 v (Distortion Factor 0.002% or less)
Output impedance Pre Out : 47 Ω
Rec Out : 100 Ω
Total harmonic distortion factor
(20 Hz to 20 kHz)
Phono MM1, 2, MC : 0.005% or less (Rec Out : 145 mV)
Tuner, AUX1, 2 : 0.005% or less (Pre Out : 1 v)
Monitor1, 2, 3 : 0.005% or less (Pre Out : 1 V)
Cross modulation distortion factor
(60Hz:7kHz=4:1)
Phono MM1, 2, MC : 0.002% or less (Rec Out : 145 mV)
Tuner, AUX1, 2 : 0.002% or less (Pre Out : 1 v)
Monitor1, 2, 3 : 0.002% or less (Pre Out : 1 V)
Frequency characteristic Phono : 20 Hz to 20 kHz ± 0.2 dB
Tuner, AUX : 1 hz to 150 khz -0.5 db
Monitor : 1 Hz to 150 kHz -0.5 dB
Input sensitivity
(Pre Out:1V)
Phono MC : 220 μ V (when using LUX transformer 8020)
Phono MM1, 2 : 2.2 mV
Tuner, AUX1, 2 : 145 mv
Monitor1, 2, and 3 : 145 mv
Input impedance Phono MC : 20 Ω ~ 40 Ω (when using LUX transformer 8020)
Phono MM1 : 50k Ω
Phono MM2 : 100 Ω, 50k Ω, 100k Ω
Tuner, AUX1, 2 : 60k Ω
Monitor1, 2, 3 : 60k Ω
Signal-to-noise ratio (IHF-A
Input short)
Phono MC : 78 dB (when using LUX transformer 8020)
Phono MM1, 2 : 80 dB
Tuner, AUX1, 2 : 100 dB
Monitor1, 2, 3 : 100 dB
Tone control LUX System NF Type with Bending Point Frequency Switching (Bypass possible)
Low-frequency curve point : 55 Hz, 77 Hz, 110 Hz, 155 Hz, 220 Hz, 310 Hz, 440 Hz, 620 Hz, 880 Hz
High-frequency bending point : 440 Hz, 620 Hz, 880 Hz, 1.2 kHz, 1.7 kHz, 2.5 kHz, 3.5 kHz, 5 kHz, 6 kHz
Variation : -8dB, -4dB, -2dB, -1dB, 0 db, 1 db, 2 db, 4 db, 8 db
Subsonic filter 6dB/oct, 10Hz/off/20Hz
12dB/oct, 10Hz/off/20Hz
18dB/oct. with both filters on
High-cut filter 6dB/oct, 9kHz/off/15kHz
12dB/oct, 9kHz/off/15kHz
18dB/oct. with both filters on
Attachment MM-2 Capacitance Switching (50 pf, 100 pf, 300 pf)
Tape monitor Route 3
Tape dubbing
Low Boost Switch (50Hz/off/100Hz)
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption 30W (Electrical Appliance and Material Control Law)
AC outlet Switched : 2 systems, total900W
Unswitched : 4 lines, total200W
External dimensions Width 498x Height 180x Depth 350 mm
Weight 11.5kg