Sony TC-4550SD (1978–1981)

A portable cassette recorder with Dolby B/C noise reduction and dual capstan transport, built for high-fidelity mobile recording.

Overview

Sony's flagship portable cassette recorder during the late 1970s, representing the pinnacle of their consumer cassette technology before digital formats emerged. The TC-4550SD delivers neutral, transparent sound with excellent frequency response and low distortion, making it one of the most accurate-sounding cassette decks of its era. Designed for professional-grade mobile use, it features a robust 3-power supply system and advanced transport stability.

Specifications

Year of Production	1978-1981
Heads	Erase : 1, Recording : 1
Motor	For Capstan : Frequency Servo Motor with FG, For Quick Winding : DC Motor
Signal-to-noise ratio	61 dB (Dolby off, Peak Level, Duadcassette)
Frequency characteristic	20 Hz ~ 20 kHz (Dual Cassette)
Wow and flutter	0.065%wrms
Distortion factor	1.2% (Du Ad Cassette)
Monitor output	500mW(EIAJ)
Power	100 VAC (Attached AC Pack Used)
Dry battery	12 v (D 1x8)
Car Battery	(Optional DCC-130 Used)
Battery life	About 40 Hours (Eveready Alkali AM-1), Approximately 12 hours (Sony Super SUM-1S)
Power consumption	7 VA (at AC)
External dimensions	Width 370x Height 110x Depth 240 mm
Weight	5.2 kg (including dry batteries)
Power Specifications	N/A (cassette deck, no power amplification)
Impedance	N/A (line-level output device)
Sensitivity	N/A (line-level output device)

Design

Features two motors: a variable reluctance type frequency servo motor with FG for the capstan and a DC motor for quick winding. Anti-rolling effect via sample-and-hold wide-band servo ensures stable drive during mobile use. Uses an F & F head with direct coupling to the reproducing amplifier for improved characteristics. Includes a 3-step switching tape selector with independent bias and equalizer, microphone attenuator, Sony Limiter switch, Dolby NR system, and MPX filter. Playback speed tuning is adjustable up to ±6%. Monitor speaker offers ON/OFF and L/L+R/R mode switching with master volume control. Powered by AC (via included pack), dry batteries, or optional car battery using DCC-130. Includes DC-DC converter for amplifier linearity, memory light (10-second activation), auto shut-off, and comes with a shoulder belt.

Context

Listed in Sony's "Classic Models Reference" table as a flagship model. A dedicated carrying case, LC-4550 (¥6,000), was sold separately.

Market

Current market value ranges from $300 to $800 depending on condition and cosmetic appearance, with a collectibility rating of 8/10. Common maintenance issues include belt deterioration, idler tire hardening, solenoid mechanism lubrication, head wear after heavy use, capacitor aging in power supply, and meter bulb replacement.

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