Audio Database


Lo-D SR-3100
49,800yen(around the 1975 time)

The AM/FM stereo receiver which collected the receiver technology of the Lo-D and aimed at the cost cut.

In FM tuner part, the dual gate MOS FET and triple variable condenser AGC are adopted as front end.
Moreover, quadrature detection with high high-integrated IC, IF section of a four-element phase linear ceramics filter, and reliability has realized the good distortion and the S/N property.

The multi-demodulator circuit has adopted the double balance type differential switching circuit, and has obtained the stable separation.

The power amplifier part has adopted the OCL circuitry of the inverted Darlington scheme of a whole page hardwired connection using NPN with a sufficient linearity, and a PNP silicon transistor.

IIn order to make an input conversion noise small, the circular transistor designed by the first rank for low noises is adopted as the equalizer stage of a preamplifier part. Moreover, since it is "3 steps of ±2 power-source schemes hardwired-connection stream composition", a nakedness property is large, and since a lot of NF are applied, the low distortion has been realized to all the bands.

A mass transistor and zener diode are used for a tuner, an equalizer, and the driver stage, and the voltage fluctuation of AC line and the cross interferencee between each circuitry inter-block and a channel are suppressed by supplying by a respectively separate rectifier circuit and constant-voltage regulated power supply.

The four-element phase linear filter and the balanced type mixer of high-integrated IC are adopted as AM tuner part.

The mic mixing circuitry and FM muting organization are carried.


Rating of a mode
Form FM/AM receiver
<Power amplifier part>
Effective output
1kHz, both ch(es) drive : 18W+18W (4ohms)
15W+15W (8ohms)
1kHz, one-side-channel drive : 22W/22W (4ohms)
19W/19W (8ohms)
Dynamic power (IHF) 45W (8ohms)
THD 0.8% (at the time of an effective output)
0.1% (at the time of 1 / 2 effective output)
Cross modulation distortion 0.8% (at the time of an effective output)
0.1% (at the time of 1W output)
Output bandwidth (IHF) 10Hz - 50kHz
Frequency characteristic 10Hz-30kHz±2dB
Dumping factor 30 (1kHz, 8ohms) or more
<Preamplifier part>
Input sensitivity/impedance Phono: 2.5mv/50kohm
Aux: 200mV/100kohm
Tape PB: 200mV/35kohm
Mic: 7mV/30kohm
Phono maximum permissible input 100mV (RMS, 1kHz)
Tone control Bass: ±10dB (100Hz)
Treble: ±10dB (10kHz)
Loudness control (Volume-30dB) + 9dB (100Hz), +5dB (10kHz)
S/N (IHF, A network, input short-circuit) Phono:65dB
Aux, Tape PB: 70dB
<FM tuner part>
Practical speed (IHF) 1.9 microvolts
Capture ratio 1.0dB
Effective selectivity 52dB
S/N 67dB
THD (400Hz) mono:0.3%
Separation 41dB(1kHz)
<AM tuner part>
Practical speed (IHF) 20 microvolts
Selectivity 35dB
Image stonewalling ratio 56dB
The semiconductor used Transistor: 16 pieces
FET: One piece
IC: Five pieces
Diode: 25 pieces
Supply voltage AC100V, 50Hz/60Hz
Power dissipation (Electrical Appliance and Material Control Law) 55W
Dimensions Width 413x height 136x depth of 376mm
Weight 7.6kg