Audio Database


LUXMAN SQ503 48,000yen(November, 1969 release)

The Integrated Amplifier which considered the balance of a performance, musicality, a style, user-friendliness, etc., and repeated the enhancement based on SQ606, SQ505, etc.

The semi- complimentary SEPP OTL scheme is adopted as a power amplifier part.

It has the composition of having excluded the protection network by using original usage.

After a preamplifier part receives a two-step hardwired-connection NF type equalizer circuitry in the emitter-follower stage and changes an impedance, it is amplified to suitable level with middle NF amplifier, and has the composition of carrying out tone control by the LUX scheme NF type tone control.
The transistor for low noises selected carefully is adopted as this fraction.

Two speaker terminations are carried.

The tone control has adopted the right-and-left standalone version. Moreover, 18dB gain can be dropped on an Attenuator switchpoint.

Since there is a tapes monitor switchpoint, a simultaneous play monitor can carry out on the tape recorder of three heads etc.

A whole surface panel and thumbs carry out the hairline manipulation of the aluminum material, and alumite dyeing of the white gold has been carried out.
Moreover, the wood case serves as rosewood finish.


Rating of a mode
Form Solid-state integrated amplifier
Consecutive output 30W/30W (8ohms)
20W/20W (16ohms)
THD 0.5% or less (30W, 8ohm, 1kHz)
Frequency characteristic 50000Hz [ 20Hz - ]-less than 2dB
Dumping factor About 30 (8 ohms, 1kHz)
Input sensitivity/impedance Phono: 2mV/50kohm
AUX2, Tuner, Tape Play : 120mV/150kohm
SN ratio Phono: 60dB or more
AUX1, 2, Tuner, Tape Play: 70dB or more
Tone control With a curving [ LUX scheme NF type ] point switching
Loud sound: 2k, 4kHz
Bass: 400, 200
Remains noise 0.5mV or less
Attachment Attenuator: -18 dB/oct.
A-B speaker change-over switch
Tapes monitor switchpoint
Headset jack
The semiconductor used
Transistor (27 pieces) 610:4 ST(s)
606:2 2SAs
2SC693Gu: 12 pieces
694:4 2SCs
734:1 2SCs
959:4 2SCs
Diode (three pieces) 13:2 DSs
DS16B: One piece
Varistor (two pieces) 265:2 kilo bytes
Supply voltage AC100V, 50Hz/60Hz
Power consumption 120W (at the time of the maximum output)
Dimensions Width 450x height 160x depth of 268mm
Weight 10kg