Sony SS 7330
A bookshelf speaker system using Sony's Ultra Linear Magnetic Path technology for reduced distortion
Overview
The Sony SS-7330 ULM33 is a 3-way bass reflex speaker system designed for high-fidelity audio reproduction. Built around Sony's ULM (Ultra Linear Magnetic Path) magnetic circuit technology, it targets low distortion through precise magnetic field control. The system uses a 30 cm cone woofer for low frequencies, a 10 cm cone midrange, and a 2.5 cm dome tweeter, housed in a bookshelf-sized enclosure made from 20 mm hard particleboard. It features level controls for middle and high frequencies and a switch to bypass the internal crossover for direct driver operation.
Specifications
| Model Rating Method | 3-Way, 3-Speaker, Bass reflex system, Bookshelf Type |
| Unit For low band | 30 cm cone type |
| Unit For Medium Range | 10 cm Cone Type |
| Unit For high-pass | 2.5 cm dome type |
| Playback frequency band | 40 Hz to 20000 Hz |
| Output sound pressure level | 88dB/W/m (New JIS) |
| Impedance | 6 Ω |
| Maximum allowable input | 100W (weighted pink noise) |
| Crossover frequency | 600 Hz, 3.5 kHz |
| External dimensions | Width 390 x Height 636 x Depth 310 mm |
| Weight | Approx. 22 kg |
Design
The SS-7330 uses Sony's Ultra Linear Magnetic Path (ULM) magnetic circuit, where a notch in the center pole with copper plating reduces nonlinear magnetic distortion. A metal bobbin and special alloy resin adhesive increase power handling in the woofer, while a high-rigidity cone extends piston vibration range and minimizes internal loss. The network includes large air-core coils to prevent distortion under high input, and a dust cap with sound insulation suppresses abnormal noise. The enclosure’s decorative edge is shaped to reduce acoustic interference, and level controls for mid and high frequencies are provided. A switch allows removal of the LC network for direct tri-amp driving of the drivers.
Market
The SS-7330 was listed for CAD $200.00 in September 2022 with no shipping due to weight. It is noted as being very rare and desirable among collectors.
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