LUXMAN L-48X

Commentary

Stereo pre-main amplifier with duo-beta-plus-X circuit.

The duo-beta circuit developed as a crystal of NFB technology is used for all stages of the amplifier.
The duo-beta circuit is designed to set two NFBs on the assumption that it is an amplifier with excellent naked characteristics that does not require NFB. First, an appropriate amount of NFB is applied to the entire band for rich sound quality, and then a DC servo is combined to tighten the sound image from ultra-low frequencies outside the audible band.
As a result, harmful 1/f noise and flicker noise are eliminated, and the ability to reproduce the subtle atmosphere of the sound field is realized.

The power supply section is equipped with a plus-X power supply with sufficient stability control by a powerful power supply.
The Duo-Beta concept is adopted, in which a power source with a sufficiently low impedance is constructed by using a large transformer and a large capacitor, and then the optimum feedback amount for sound quality is set.

The L-48X eliminates coupling capacitors between stages and other capacitors that cause sound coloring from the signal path. It also takes measures against DC drift, which is a prerequisite for this. In the equalizer section with a particularly high amplification factor, a DC servo using an FET input operational amplifier is constructed to obtain a highly stable servo effect.

Equipped with a phono straight function. When the switch is turned ON, the input selector, REC selector, filters, balance volume and mono switch are disconnected, and the equalizer and power section are directly connected.
In addition, contacts and shielding wires are completely eliminated, and the circuit configuration can be changed to a simple circuit configuration that can be called a dedicated disk amplifier.

Equipped with a high-quality, high-gain equalizer, most MC cartridges can be directly connected without additional circuitry such as an MC head amplifier.
This equalizer uses a cascode-connected FET differential amplifier as an input and an A-class single-ended push-pull output to obtain excellent naked characteristics. In addition, it uses a duo-beta circuit to achieve sound quality.

Equipped with a warm-up indicator, it detects the temperature inside the amplifier and turns off the lit LED.
You can confirm at a glance that the operation of the circuit has entered a stable state.

The tone control circuit is incorporated into the NFB loop of the power amplifier section, and simple circuit configuration is used to obtain simple change characteristics.

Equipped with a REC selector, you can take out the recording output regardless of the source that is currently playing.

The phono input terminal, which handles small signals, uses gold plating with low connection loss.

Model Rating

Type	Stereo integrated amplifier
Continuous effective output	80W + 80W (8 Ω, both channel operation, 1 khz)
Total harmonic distortion factor	0.009% or Less (8 Ω, Rated Output -3dB, 20 Hz to 20 kHz)
Cross modulation distortion factor	0.009% or Less (8 Ω, Rated Output -3dB, 60 Hz : 7 kHz = 4 : 1)
Frequency characteristic	Phono MM : 20 Hz to 20 kHz ± 0.3 dB Tuner, AUX, Monitor1, 2 : 10 Hz to 100 kHz -3dB
Input Sensitivity / Impedance	Phono MM : 1.6mV/50k Ω Phono MC-1 : 1.6mV/100 Ω Phono MC-2 : 0.25mV/100 Ω Tuner, AUX, Monitor1, 2 : 200mV/40k Ω
Signal-to-noise ratio (IHF-A)	Phono MM : 80 dB or more Tuner, AUX, Monitor1, 2 : 110 dB or more
Tone control	Low-Range Curve Point : 200 Hz, 400 Hz (Can Be Defeated) High-Frequency Curved Point : 2 kHz, 4 kHz (Capable of Defeat)
Filter	Subsonic : 15 Hz, off, 30 Hz High-cut : 9 kHz, off, 15 kHz
Low boost	70 Hz, off, 150 Hz
Attachment	Phono straight switch Mono switch Signal OFF switch Warm-up indicator Speaker selector Headphone jack
Power supply voltage	100 VAC, 50Hz/60Hz
AC outlet	Power switch interlock : 100W Power switch not linked : 100W
Power consumption	180W (Electrical Appliance and Material Control Law)
External dimensions	Width 464x Height 156x Depth 332 mm
Weight	11.0kg