LUXMAN 5F70

Commentary

Tone control amplifier designed for the laboratory reference series.

The 5F70 uses a newly developed DML-IC newly developed DML-IC at key points to provide perfect drift control without compromising the original sound quality.

The basic configuration consists of a tone control circuit and an acoustic control circuit.

The tone control circuit has a newly developed FET with low notching and high Gm (forward transfer admittance). Moreover, the differential amplifier circuit is composed of FET with well-balanced both units. The DC amplifier configuration is basically composed of FET with current mirror circuit, cascode circuit, constant current circuit, etc., and DC drift is prevented by effectively arranging DML-IC where DC gain exists.
Both boost and cut tone control uses a CR-type circuit for both boost and cut. The high-range tone control uses an NF-type circuit for boost and a CR-type circuit for cut.

The acoustic control circuit employs a twin T-type circuit to effectively eliminate harmful standing waves generated in the listening room. The function of the twin T-type circuit is completed by effectively arranging the buffer circuit.
This buffer circuit consists of a differential amplifier circuit with newly developed FET, and is a DC amplifier structure with effective arrangement of current mirror circuit and constant current circuit.

The tone control function enables fine tone control by setting the bending point frequency to four points in each of the low and high ranges.

The acoustic control function consists of three components : the frequency control, which continuously changes the dip frequency from 75 hz to 150 hz, the attenuation control, which continuously changes the dip amount from 0 to -12dB, and the bandwidth control (Q can be continuously changed from about 1 to about 20), which can produce from steep dip characteristics to gentle dip characteristics. By operating these components, it is possible to effectively eliminate standing waves that adversely affect sound quality.

It is equipped with a bypass switch to check the tone control effect.

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	Tone control amplifier
Output voltage	1 v (Standard) 4.5 V or more (maximum)
Output impedance	500 Ω
Total harmonic distortion factor	0.005% or Less (Output 2 V, 20 Hz ~ 20 kHz)
Cross modulation distortion factor	0.005% or Less (Output 2 v, 60 hz : 7 khz = 4 : 1)
Input sensitivity	1V
Input impedance	100k Ω
Frequency characteristic	10 Hz to 100 kHz -1dB
Gain	0dB
Signal-to-noise ratio	104 dB or more (IHF-A curve correction, input short circuit)
Level control	Maximum ± 12 dB (continuously variable, at each bending point switching position)
Bending point frequency	Low frequency : 125 Hz, 250 Hz, 500 Hz, 1 kHz High : 1 kHz, 2 kHz, 4 kHz, 8 kHz
Acoustic control	Dip Frequency : 75 Hz ~ 150 Hz (Continuously Variable) Attenuation : 0 dB ~ -12dB (continuously variable) Bandwidth (Q) : about 1 to about 20 (continuously variable)
Crosstalk	-80dB or less
Residual noise	0.045 mV or less
Attachment	Acoustic control Tone defeat switch
Power consumption	10W
External dimensions	Width 442x Height 57x Depth 400 mm
Weight	5.1kg