SONY SS-5050II

At 20.5kg, these bookshelf cabinets carry a lot of engineering - wood and drivers, plus a philosophy of control.

Overview

The SONY SS-5050II doesn't shout for attention with flash or finish. It's a 3-way, 3-speaker, airtight type system built for precision. Marketed as a bookshelf type, its 630mm height and 365mm width suggest modest placement, but the 20.5kg mass tells a different story: dense bracing, heavy drivers, and a deliberate refusal to rattle under load. It was priced at ¥52,000 around 1975. The Vintage Technology Archive designates it a "Legendary Product," though concrete details about its original reception are absent from the record.

Specifications

Manufacturer	Sony
Product type	3-Way, 3-Speaker, Airtight Type, Bookshelf Type speaker system
Original price	¥ 52,000 (1 unit, around 1975)
Effective frequency band	40 Hz to 20000 Hz
Output sound pressure level	91dB/W/m
Impedance	8 Ω
Maximum allowable input	80W
Crossover frequency	800 Hz, 8000 Hz
External dimensions	Width 365x Height 630x Depth 318 mm
Weight	20.5kg
Low-frequency driver	30 cm cone type
Midrange driver	3.5 cm Dome Type
High-frequency driver	2.5 cm dome type

Key Features

30 cm CARBOCON Cone with Radial Carbon Fiber Edge

The low-frequency driver is the anchor of the design. Its 30 cm cone is made from CARBOCON, a blend of carbon fibers in a resin matrix. That gives high rigidity and low mass, which helps keep breakup modes and transient smearing down. Sony also mixed carbon fibers radially into the roll edge to suppress deformation and division vibration during large excursions. The aim looks like linearity at higher volumes, where a typical rubber or foam surround might introduce non-linearities.

High-Flux Magnetic Circuits Across All Drivers

Magnetic field strength is well documented for all three drivers. The low-frequency unit uses a 120 mm diameter magnet producing 11,000 gauss in the air gap. The midrange steps up to 13,000 gauss with a 110 mm magnet. The high-frequency driver goes further, at 15,000 gauss. Fields this dense improve motor control, reduce distortion and help transient response, since the voice coil sits in a strong, uniform magnetic field.

Hard Aluminum Alloy Foil Dome Tweeter

3.5 cm Composite Midrange with Viscoelastic Damping

The midrange unit is a 3.5 cm dome type made from a blend of special fibers and viscoelastic resin, then coated with a special damping agent after molding. The layering targets internal resonances and breakup, and aims for a smooth transition between the woofer and tweeter. The 13,000 gauss magnetic circuit keeps tight control over this band, where even minor distortion is easy to hear.

Long Travel Voice Coil Drive System

The long travel voice coil system means the SS-5050II was designed for dynamic range, not only for fidelity at moderate levels. It lets the 30 cm woofer stay linear during deep bass passages, which supports the 40 Hz low-end claim without needing excessive cabinet volume. The 50 mm bobbin, wound with heat-resistant treated wire, suggests an effort to manage thermal compression during sustained high-power operation.

Collectibility & Value

Similar items on eBay

No exact Sony SS 5050II listings are live right now — these searches show current Sony and similar vintage audio gear on eBay:

Search Sony SS 5050II on eBay Browse Sony audio gear on eBay

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.