LUXMAN 5L15

Commentary

DC configuration pre-main amplifier of the laboratory reference series.

The 5L15 incorporates the equalizer circuit of the preamp 5C50 into the power amplifier 5M21 of the Laboratory Reference Series.

The 5L15 consists of an equalizer consists of an equalizer circuit and a power amplifier circuit. It employs a DC amplifier configuration to faithfully amplify all program sources, thereby eliminating phase distortion in the low range and transient distortion in the high range.
5L15 solves the problem of DC-drift due to changes in temperature and other external conditions. This problem is solved by installing a DML-IC (Dual Monolithical Linear-Integrated Circuit), which contains a newly developed FET-based differential-amplifier circuit, a supplementary cascode circuit, current mirror circuit, constant current circuit, and other circuits.

In order to eliminate the notching distortion that is a problem in power amplifiers, the elements used in the output stage have been studied and the switching speed of the driver stage has been improved in a circuit manner. Thus, the level of notching distortion is higher than that of A-class operation in spite of AB-class operation.

The cascode circuit, current mirror circuit, emitter follower circuit, constant current drive circuit, etc. are arranged in the right place in order to make all circuits show the maximum power, which is useful for improving basic performance and preventing DC drift.

It is designed with the minimum necessary functions, and all sound adjustment functions such as tone control are omitted.

It is equipped with a large power meter of independent right and left channels which displays average output at 8 Ω load in W.
This meter is equipped with a range switching function.

Equipped with a DC offset sensor, it can check DC component is input from the outside.
In addition, it is equipped with an input capacitor IN/OUT switching function so that when a DC component appears at the output terminal, it can be cut off at the main input.

It is equipped with a preset attenuator, two types of tape monitor function, and a tape dubbing function.

As a protection circuit, a DC drift detection circuit and an excess input detection circuit that work to protect the speaker when a DC voltage of ± 2.5 v or more appears at the output terminal or when an excess input is input, and an eddy current prevention circuit that prevents the power transistor from being damaged by an eddy current when a short circuit occurs at the speaker terminal or the terminal of the speaker system.

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	Power Amplifier with DC Configuration Preps
Continuous effective output	80W + 80W (8 Ω, simultaneous operation of both channels, 20 Hz to 20 kHz)
Total harmonic distortion factor	0.02% or Less (8 Ω, 80W, 20 Hz to 20 kHz)
Cross modulation distortion factor	0.02% or Less (8 Ω, 80W, 60 hz : 7 khz = 4 : 1)
Output bandwidth	5 Hz to 100 kHz (8 Ω, 0.1%, -3dB)
Damping factor	80 or More (8 Ω Load, 1 kHz)
Input sensitivity	Phono:2.7mV Tuner, Aux1/2, Main in : 300 mv
Signal-to-noise ratio (IHF-A curve correction Input short)	Phono : 80 dB or more Tuner, Aux1/2, Main in : 100 dB or more
Frequency characteristic	Phono : 20 Hz to 20 kHz ± 0.2 dB Tuner, Aux1/2, Main in : DC to 100 kHz
Output voltage	Pre out : 300 mV (standard) Rec out : 300 mV (typical)
Protection circuit	DC offset sensor Speaker protection circuit with DC drift detection Eddy current prevention circuit
Attachment	Independent power meter for left and right channels Meter-range switching Input capacitor IN-OUT switching Terminal for peak indicator connection Headphone jack Phono subsonic circuit Tape monitor (2 systems) Tape dubbing circuit Attenuator
Power consumption	380W (8 Ω, both channels operate simultaneously, at rated output)
External dimensions	Width 442x Height 146x Depth 400 mm
Weight	13.3kg