Stellavox SM8

The Stellavox SM8 is a high-end professional portable reel-to-reel tape recorder, part of the Stellavox Series 8 line, designed for studio-quality recording under demanding conditions. It is recognized for its exceptional build quality, precision engineering, and versatile modular system.

• Tape Format and Speed: The SM8 records on standard ¼ inch magnetic tape and supports the common professional tape speeds of 3¾, 7½, and 15 inches per second (ips). Optional higher speeds such as 30 ips are available on special order. Additionally, intermediate speeds can be selected using an external accessory (ASV).

• Head System: It uses interchangeable modular head blocks (SHD), allowing different recording formats such as Mono, Mono-Pilot-Neo, Stereo, and Stereo-Pilot-Synchrotone. The heads are high-grade, typically made of permalloy, with bias fine adjustments integrated into the head assembly for optimal performance without the need for realignment after head changes.

• Tape Transport and Tension: The SM8 features an ingenious constant tape tension system that ensures stable tape contact and minimal wow and flutter. The tape transport uses a capstan-driven system with mechanical idle-roller governed slipping clutches to maintain precise tape tension. The pressure roller can be disengaged for editing, enabling smooth shuttle operation without switching clicks.

• Electronics and Inputs: The SM8 is a solid-state machine with multi-voltage capability and built-in battery operation, with an optional external power supply (APS 8). It has two complete recording/playback channels, each with three inputs:
  Mixer input (fixed level, high impedance)
  Line input (adjustable volume, convertible to balanced mic input with accessories)
  Balanced microphone input (200 ohms, with attenuation options)The machine supports phantom power for condenser microphones via external accessories (e.g., ALP-8), allowing up to four separately adjustable microphones.

• Noise Reduction and Signal Processing: The SM8 includes modules for automatic gain control during recording, RF filtering, and equalization. It also supports noise reduction options such as Philips Dynamic Noise Limiter. The bias oscillator frequency and level are finely adjustable for optimal recording quality.

• Frequency Response and Sound Quality: The SM8 is designed to deliver world-class recording and playback specifications, with frequency response extending well into the subsonic and ultrasonic ranges. This makes it suitable not only for audio but also for instrumentation purposes.

• Build and Design: The recorder is housed in a robust, machined aluminum case, ensuring durability and reliability. The controls are designed for professional use, with illuminated tip-touch switches and solenoid actuation for quiet and precise operation.

• Additional Features:
  Mono/stereo switch for channel configuration
  Editing facility with disengageable pressure roller for precise tape cutting
  Modular electronics with plug-in screened metal modules for easy maintenance and upgrades

• Historical and Practical Notes:
  The SM8 improved upon earlier models (like the SP7 and SP8) by increasing audio voltage headroom and maintaining nearly unchanged electronics for reliability.
  The machine is highly regarded for its sound quality, mechanical precision, and long-term reliability, though spare parts are becoming scarce.
  Some units feature XLR microphone connectors replacing the original DIN connectors for modern compatibility.