Heathkit AA-21D Vintage Stereo Amplifier RARE Fully Restored
Monday, March 2nd, 2026
Heathkit AA-21D Stereo Germanium Solid-State Amplifier – Fully Restored, Excellent Working Condition. This Heathkit AA-21D stereo germanium solid-state amplifier is an increasingly rare piece of vintage audio history-especially in this condition. A great opportunity to add a properly restored classic to a serious vintage audio collection. The amplifier has been completely restored internally and is in 100% working order. All electrolytic capacitors replaced with modern, high-quality audio-grade units. All carbon composition resistors replaced with modern metal-film resistors. Output power transistors replaced with a matched set of New Old Stock (NOS) germanium devices. Original germanium transistors are now quite rare and often noisy; this matched set performs exceptionally well. Original power cord replaced with a modern 3-prong grounded cord for improved safety. Current limiter installed to reduce wear on the main power switch. Dial and indicator lamps replaced. All controls, switches, and potentiometers cleaned for quiet, noise-free operation. The unit has been thoroughly cleaned but does show honest signs of age. Cabinet is structurally solid. Scratches and visible cosmetic wear are present (please see photos for details). Printed copy of the schematic included. Tested for approximately 2 hours paired with AR-3a speakers. Please feel free to reach out with any questions or to request additional photos.
