Audio Database

The

LUXMAN L-504
78,000yen(October, 1973 release)

Description
 
The Integrated Amplifier announced as a SQ-505 type succeeding machine.

The main-amplifier part is designed for the purpose of removing crossover distortion in which it is difficult to remove with B class push pull amplifier, and the notching distortion especially in a high region as much as possible.
The PNP type and NPN type transistor which were excellent in the high region property were appointed as B class driver stage, and the power transistor for pure complimentaries which was developed for LUX and which was excellent in the destructive-proof property which does not spoil a high region property is adopted as the power stage.
By adopting the differential-amplification circuitry by constant current drive, and driving from a non-signal time with a fixed electric current till the maximum output, the pre-driver stage maintains B class operation stage at the status that it was stabilized, and is suppressing notching distortion to the relative minimum. The transistor of this stage has high high region cut-off frequency (ft), especially, few things of the collector output capacitance (Cob) were adopted, and the distortion of the high region has also acquired the almost same value as 1kHz over full power.
All the transistors currently used for a main-amplifier part arranged the can type, and have secured moisture resistance, an endurance, and hi-reliability.

The gentle LUX scheme NF type of a transition property is used for a tone control circuit. "Height level adjustment" with a click stop, "height each curving point frequency switching" of every two points, and independent "tone-defeat switchpoint" are carried in organization.

The equalizer circuitry has obtained the linearity and high SN ratio which are a 3 steps of る hardwired-connection circuitry which is a stream composition, and were excellent in the super-low-noise type transistor of NPN-PNP-NPN with an advantageous voltage utilization factor. Distortion has acquired the outstanding numeric value, when a current amplification factor (hfe) adopts a transistor with a sufficient linearity highly.
Direct-current stability is raised fully applying a direct-current feedback to this circuitry. Moreover, the deflection with a RIAA curve is dedicated to less than ±0.5dB by making the allowable error of a using part small and suppressing variation as much as possible.

It is used for the capacitor used for an input circuit and an output circuit from the inside of a Mylar type with little leakage current, and a tantalum type, selecting carefully to it further. This is holding down the unpleasant shocking noise at the time of a switchpoint switching to the relative minimum.

Two 6800-micro F electrolytic capacitors are used for the filter circuit of a power-source part. The stable power source is realized in combination with the good power transformer of a regulation.
Power-switch ON and the muting circuit which separates a speaker circuitry at the time of OFF are prepared in the measure against a shocking noise at the time of power activation and a shutdown, and the duty of the speaker protection is also achieved.

Two speaker outputs, a main and remote, are carried and it can be used separately or simultaneous.

The Attenuator switchpoint is carried and a sound volume of -18dB can be carried out with a one button.

Rear
Internal

Rating of a mode
Form Stereo integrated amplifier
<Main-amplifier part>
Succession effective output 35W+35W (8 ohms, both channel simultaneous operation)
40W/40W (ohms [ 8 ], one-side-channel operation)
THD 0.03% or less (8ohm, 35W)
Cross modulation distortion 0.04% or less (8ohm, 35W, 70Hz:7kHz=4:1)
Output bandwidth 5Hz - -50kHz three dB (0.1%)
Frequency characteristic 10Hz - -60kHz one dB
Input sensitivity 480mV (8ohm, 35W)
Impedance 50kohm
Remains noise 0.5mV or less
Dumping factor 35 (at the time of an 8-ohm load intensity)
Attachment Attenuator (-18dB)
Main speaker switchpoint
Remote speaker switchpoint
Headset jack
<Preamplifier part>
Standard output voltage Pre out:480mV
Rec out:120mV
Maximum output voltage Pre out:4.5V
Output load impedance Pre out: About 100ohms
Rec out: About 100ohms
Frequency characteristic Aux1:10Hz-50kHz-1dB
THD 1:0.04% or less (1kHz, 1V) of Aux
Input sensitivity Phono1, 2:2.7 mV
Tuner, aux1, 2:120mV
Input impedance Phono1, 2:65kohm
Tuner, aux1, 2:50kohm
SN ratio Phono1, 2:65dB or more
Tuner, aux1, 2:76dB or more
Maximum permissible input (1kHz) Phono: 300mV (R-M-S)
850mV(P-P)
Remains noise About 25 microvolts or less
Tone control With a curving [ LUX scheme NF type ] point switching
The point curving [ low-pass ]: 150Hz, 300Hz
The point curving [ high region ]: 3kHz, 6kHz
Attachment Tapes monitor switchpoint (two lines)
Tapes dubbing mode switch
Tapes connector (DIN specification)
<Synthesis>
The semiconductor used
Transistor : 1345:10 2SCs
640:4 2SCs
2SA620K: One piece
2SC1103A: Four pieces
660:4 2SAs
959:2 2SCs
2subset-dependency188A: Two pieces
2SB545A: Two pieces
853:1 2SCs
735:3 2SCs
562:1 2SAs
496:1 2SCs
Diode : 1S1555V: Two pieces
1N4003: 4 piece
1S188:4 piece
Five B3:1 pieces
Zener diode : 120:2 WZ(s)
Varistor : SV-03: 2 piece
SV-02: 2 piece
Power consumption 150W (at the time of an 8-ohm simultaneous load intensity and the maximum output)
Dimensions Width 450x height 160x depth of 268mm
Weight 10kg