Technics SU-7300 (1976–1979)

Name: Technics SU-7300
Brand: Technics

A transistorized stereo integrated amplifier with high build quality, dual VU meters, and a service-friendly design.

Overview

The Technics SU-7300 is a stereo integrated amplifier produced from 1976 to 1979. It features a side-terminal layout with all input jacks on the right and speaker terminals on the left, enabling a straight signal path. The unit includes a phono stage with RIAA equalization, two tape loops with independent monitor and dubbing controls, and dual speaker outputs selectable via pushbutton. It was designed with serviceability in mind—removing two side panels and four screws allows the front panel and PCB to be lifted for full component access. The amplifier uses matched transistor pairs in single packages and current-mirror loading in differential stages to achieve low distortion.

Specifications

Product Type	Stereo Integrated Amplifier
Effective Output (8 Ω, 20 Hz – 20 kHz)	36W + 36W
Total Harmonic Distortion	0.08%
Signal-to-Noise Ratio (Phono)	78dB (IHF-A)
Frequency Response (Tuner)	20 Hz – 20 kHz, ±0.5 dB
Damping Factor (8 Ω)	40
Input Sensitivity / Impedance (Phono)	2.5mV / 47kΩ
Output Voltage (Tape)	150mV
Power Supply	100 VAC, 50/60Hz
Power Consumption	95W
Dimensions	410 × 140 × 315 mm
Weight	9.1 kg
Volume Control	41-step
Connectors	DIN, RCA

Design

The SU-7300 uses a pre-main amplifier design with a side-terminal configuration for a direct signal path. The phono and power amplifier stages employ differential amplifiers with current-mirror loads and matched transistor pairs in single packages to minimize distortion. The power supply includes a high-density transformer and 8,200μF filter capacitor. Germanium diodes are used in the power meter circuit for improved linearity at low outputs, and the unit features two-range (0 dB and -10 dB) direct-reading power meters. The heat sink is a single piece of aluminum, and the amplifier includes a 6–7 second delay circuit to prevent turn-on shock noise.

Market

The SU-7300 was originally priced at ¥35,800 in 1976. As of a listing on hifivintage.eu, a restored unit sold for €650.00. Common issues include crackling sounds during playback due to worn tape and record switch contacts. Electrolytic capacitors are prone to aging and leakage, and restoration typically involves replacing these and cleaning controls with DeoxIT. A service manual is available for repair.