General Radio Oscillator 1390-A 50-70's - old

Industrial-grade random noise generator and analog oscillator built by General Radio (Cambridge, MA), later tagged for use by Hughes Aircraft. Originally designed for lab testing and calibration, but it translates surprisingly well into audio and modular synth environments.

Unit Details

• Model: General Radio Type 1390-A

• Hughes Aircraft inventory tag intact

• Analog Output Volts meter (General Radio MEDS-48)

• Frequency range selector: approx. 20 kc to 5 Mc

• Output level control with Low / High switch

• 1/4” output jack plus additional connector

Condition

• Powers on and operates, though not recently calibrated

• Heavy vintage wear and patina consistent with real lab use

• Meter, switches, and controls intact

• All knobs present

• Untouched cosmetically. What you see is original

Why it’s interesting

• Functions as a true analog noise source and oscillator

• Works well patched into a modular synth rack or Eurorack setup with proper level matching

• Produces raw, unstable, non-digital noise textures that modern modules don’t really replicate

• Can be used for sound design, feedback loops, drones, and experimental audio

This is not a polished synth module. It’s old lab equipment repurposed into an instrument, which is exactly why it’s compelling. It has unpredictability and character that you don’t get from clean modern gear