Stellavox SP 9

The Stellavox SP9 is a professional portable reel-to-reel tape recorder renowned for its high mechanical quality and versatility, designed and manufactured in Switzerland by Stellavox.

• Type and Application: The SP9 is a solid-state, portable reel-to-reel tape recorder intended for professional use, including broadcast and location sound recording.

• Tape Format and Heads: It features a 3-head, 3-motor design allowing for stereo recording and playback in half-track format. The heads are made of permalloy, a magnetic alloy known for excellent recording and playback fidelity.

• Tape Speeds and Reel Size: The SP9 supports three tape speeds: 3¾, 7½, and 15 inches per second (ips). It can handle reels up to 7 inches in diameter, with optional external adapters allowing larger reels up to 10.5 inches.

• Frequency Response: At 7½ ips in stereo, the frequency response ranges from 30 Hz to 18 kHz, and in mono from 20 Hz to 16 kHz, with a ±2 dB tolerance. This provides high-fidelity audio reproduction suitable for professional applications.

• Signal-to-Noise Ratio and Wow & Flutter: The unweighted signal-to-noise ratio is approximately 60 dB at 7½ ips stereo and slightly higher at 15 ips (61-62 dB). Wow and flutter, which measure speed stability, are very low at ±0.07% (DIN45507), indicating excellent tape transport precision.

• Electronics and Controls: The SP9 is a solid-state machine with multi-voltage capability, making it adaptable for various power environments. It does not have auto-reverse functionality but offers plug-in head blocks and accessories for instant format, function, and tape alignment changes, enhancing its versatility in the field.

• Sound and Reliability Ratings: It is rated highly for sound quality (8/10) and long-term reliability (8/10), reflecting its reputation as a durable and sonically excellent recorder.

Historical and Design Context

• The SP9 was developed by Stellavox founder Georges Quellet, who was an early pioneer in tape recorder design. The company’s products, including the SP9, were often compared to Nagra recorders but distinguished by their compactness and precision Swiss craftsmanship.

• Stellavox machines like the SP9 were widely used by radio, TV stations, and motion picture location sound mixers due to their portability and professional-grade performance