Note
QST, Feb 1977, p. 4.
QST, Jan 1978, p 175.
QST, Jul 1978, p. 4. (MLA-2500B) $899.50.
QST, Jul 1981, p. 111.
The Dentron MLA-2500 is a compact, high-power linear amplifier designed by Dentron Radio (Twinsburg, Ohio) primarily for amateur radio service, though it also found use in commercial, military, and research applications.
-Features
– Cooling System: Features a dual-speed forced-air cooling system directed at the final tubes (in grounded grid) and output stages.
– Uses two EIMAC 8875 external-anode ceramic/metal triodes operating in grounded grid.
– Includes an automatic high-speed override if tube plate temperatures exceed 200°C, as well as a manual continuous duty switch to run the cooling system at maximum speed.
– Tank Circuitry: Uses a high-efficiency tank circuit wound with Teflon-covered conductor composed of 19 silver-plated wires. This design allows for closer windings, improved harmonic suppression, and enhanced protection in high-humidity or salty environments.
– Generates high plate voltage (~2,300 V DC).
– Power Supply: Accepts either 117 VAC or 234 VAC input (234 VAC at 15 A recommended), with rear-panel accessible line fuses and transformer taps.
– Equipped with a safety interlock circuit breaker system that cuts voltage if the cabinet covers are removed.
– Metering & Controls: Features twin 3-inch meters: one dedicated RF Wattmeter (which functions whether the amplifier is switched in or out of line) and a multimeter for monitoring plate voltage, plate current, and grid current.
– All internal alignment controls (wattmeter calibration, ALC, transformer taps) are accessible without removing the cabinet covers.
– Covers MARS frequencies without modifications
Specifications
– Frequency Coverage & Power Rating: Covers 160 through 10 meters.
– Rated for 2,000 Watts PEP (SSB) and 1,000 Watts DC input (CW/RTTY) in amateur service, with power capabilities exceeding 2,000 Watts in commercial and military applications.
– Power Output & Efficiency: Yields over 700 Watts output at 1 kW input (~70% efficiency) and up to 1,000 Watts output at 1,336 Watts DC input (~74% efficiency).
– Harmonic suppression is rated at better than 55 dB at full power across all bands.
– Drive Requirements: Requires only 36 Watts of drive for 1 kW input and 65 Watts of drive for 2 kW PEP output.
Tubes:
(2) 8875 forced-air cooled ceramic/metal triodes.
Optional 19-inch rack panel mounting kit and a front-panel tilt bail were available.
