Revox - A 78 Solid state integrated amplifier

Revox A78 vintage integrated stereo amplifier ("80 Watt All Silicon Stereo Amplifier A 78"), designed by Willi Studer and built in Switzerland/Germany (circa 1971–1977). Technically in 100% fully functional condition and visually in very neat vintage condition with light signs of use commensurate with age.

For collectors and audiophiles, the A78 is an icon from the early 1970s. Studer Revox applied uncompromising studio standards to a consumer amplifier. This translates directly into the construction: a heavy wooden enclosure combined with a matte black control panel, brushed aluminum accents and solid aluminum knobs. Under the hood, the unit is built entirely with silicon transistors (all-silicon) on modular plug-in cards, a construction method borrowed directly from professional Studer mixing consoles.

In sonic terms, the A78 offers an extremely linear, dry, and uncolored studio sound with controlled low-end presentation and high channel separation. Characteristic of the amplifier are the dual concentric knobs by which tone control and balance are independently adjustable per channel. In addition, the front panel features studio-oriented switches for Low Filter, High Filter, Loudness and Presence (+3.5 dB correction in the speech region around 2.5 kHz), as well as dual headphone outputs and a separate tape output on the front.

Specifications
Type: integrated stereo hi-fi amplifier (all-silicon solid-state)
Model: Revox A78 (A 78)
Manufacturer: Willi Studer / Revox (Regensdorf, Switzerland / Löffingen, Germany)
Year of manufacture: circa 1971–1977
Continuous power (RMS / sine): 2 x 40 W at 4 Ohm, 2 x 35 W at 8 Ohm (both channels loaded)
Music power (peak): 2 x 50 W at 4 Ohm (total 80–100 W)
Frequency response: 20 Hz – 20,000 Hz (±1 dB)
Total Harmonic Distortion (THD): < 0.1% at nominal power (1 kHz)
Intermodulation distortion: < 0.3%
Damping factor: > 20 at 4 Ohm
Signal-to-noise ratio: > 65 dB (Phono / Mic), > 75 dB (Tuner, Tape, Aux)
Tone controls: Bass (±12 dB at 60 Hz), Treble (±12 dB at 12 kHz), adjustable per channel
Filters & corrections: Low Filter (-12 dB/octave below 50 Hz), High Filter (-12 dB/octave above 8 kHz), Presence (+3.5 dB at 2.5 kHz), Loudness
Inputs: Phono MM (RCA/DIN), Microphone (DIN), Tuner (DIN), Tape (DIN), Aux (DIN)
Outputs: Tape Out (DIN rear and 6.3 mm front jack), Pre-Out / Main-In switchable
Headphone connections: 2 x 6.3 mm stereo jacks on the front panel (Phones)
Speaker connections: DIN speaker sockets for 2 pairs (A / B)
Mains voltage: 110, 130, 150, 220, 240, 250 V AC (switchable, 50/60 Hz)
Dimensions (W x H x D): 41.5 x 16.0 x 24.5 cm
Weight: approx. 8.2 kg