NF20

About the NF20

The Grundig NF-20 is a stereo audio amplifier produced by Grundig Radio-Vertrieb, RVF, Radiowerke in Fürth, Germany around 1965-1966. It is a tube amplifier using 6 tubes in total, including four EL84 (6BQ5) output tubes and two ECC83 (12AX7) preamp tubes. The amplifier delivers 30 watts of power output via two push-pull EL84 end stages, each providing 15 watts. It was designed to be connected to external speakers and stereo radio receivers such as the HF10L. The NF-20 features a metal chassis measuring approximately 245 x 140 x 220 mm and weighs about 10 kg. It uses an AC power supply compatible with 110, 125, 220, and 240 volts. The amplifier originally came with octal sockets for preamp and speaker connections, but many units have been modified with modern RCA inputs and speaker terminals for contemporary use. The NF-20 is highly regarded for its sound quality, often praised for its clear, open, and musical presentation, making it a sought-after amplifier among audiophiles and vintage audio enthusiasts. Restorations typically involve replacing capacitors with modern equivalents, upgrading rectifiers, and improving grounding and wiring to maintain or enhance sound character. It is considered one of the finest EL84 push-pull amplifiers from the era, known for its robust German-made transformers and simple yet effective circuit design.