The Raytheon RL-10 Audio Amplifier is a classic peak-limiting amplifier built for high-quality AM and FM broadcast programme chains. Designed during the golden age of vacuum tube broadcasting equipment, the EL-10 was developed to maintain consistent output levels by automatically reducing gain when input signals exceeded a predetermined threshold.
This made it an essential tool for early radio transmission and mastering, ensuring clarity and avoiding distortion in transmission lines.
The Raytheon RL-10 features three push-pull tube audio stages and a dedicated audio rectifier circuit, all powered by an integrated high-voltage power supply. It provides a maximum gain of 43 dB and a robust output level of +23 dBm, with exceptionally low noise and distortion figures for its era.
With a wide frequency response of 30 Hz to 15,000 Hz and a high compression ratio of 10:1, the Raytheon RL-10 was engineered to deliver high fidelity while preserving control over dynamic content.
The Raytheon RL-10’s front panel is fully equipped for operational flexibility, offering variable recovery time (from 0.2 to 1.0 seconds), linear input and output gain controls in 1.5 dB steps (up to 30 dB), and a multi-function meter switch that allows detailed monitoring of various tube voltages and plate currents.
The Raytheon RL-10 amplifier uses seven tubes in total, including iconic types such as the 1612, 6SJ7, 6V6, and 5U4G, and is housed in a 19-inch relay rack panel. Its pull-out front panel design provides full serviceability, reflecting the practical engineering values of mid-century American broadcast equipment.
Features
- Peak-limiting amplifier designed for AM/FM programme control
- Automatic gain reduction when input exceeds threshold
- Three push-pull audio stages with high-fidelity tube design
- Integrated audio rectifier circuit and dedicated power supply
- 43 dB gain with 600-ohm input and output impedance
- Output level up to +23 dBm
- Wide frequency response: 30 Hz to 15,000 Hz (±1 dB)
- Low distortion: under 1% even at 0.5 dB compression
- High compression ratio of 10:1
- Adjustable recovery time: 0.2 to 1.0 seconds (5 positions)
- Linear input and output controls in 1.5 dB steps, up to 30 dB
- Multi-function metering for tube current and voltages
- Rugged 19-inch rackmount chassis with pull-out front panel
- Raytheon Woodland Brown finish (custom options available)
- Uses classic metal tubes including 1612, 6SJ7, 6V6, and rectifiers
- Fully front-serviceable with all tube access from front panel
