This is old schematic of Fisher Amplifier 70A series.
Specification
Power output: 50 watts into 8Ω.
Frequency response: 20Hz to 20kHz.
Total harmonic distortion: 0.2%
Damping factor: 20.
Input sensitivity: 2.5mV (MM), 150mV (line).
Signal to noise ratio: 65dB (MM), 85dB (line)
Dimensions: 400 x 105 x 243mm
Weight: 5.4kg
Some images of Fisher 70a Series.
Images from here.
The Origin Of Fisher
Avery Fisher is the Founder of Fisher Radio Enterprise. From years of 1945 “Fisher” was a standout amongst the most popular High Devotion brand in 1950 – 60’s.
Avery Fisher was a musician. He started a striking vocation by structure radios to improve sound quality for his own delight. His accomplishments incorporate the primary transistorized intensifier and the stereo radio phonograph mix. He sold his hi-fi segments at premium costs, acquiring them a notoriety for being the Cadillac of sound gear.
Fisher graduated in 1929 from New York College. He worked for two distributing firms; G. P. Putnam’s Children and Dodd Mead and Friends. There he started his undertakings in sound structure. The Fisher Radio’s logo was created by him. He built his radios to get preferable sound over accessible models conveyed. By 1937 he had made noteworthy enhancements in the plan of intensifiers, tuners and speakers and set up his first organization, Philharmonic Radio.
After WWII Fisher sold Philharmonic Radio and started a second audio company in New York, Fisher Radio, which produced high-fidelity components from a factory on the site now occupied by Lincoln Center. His engineering staff was comprised of the brightest audio technicians lured away from European companies.
In 1956 Fisher produced the first transistorized amplifier. They developed the first stereo radio and phonograph combination. From 1959 to 1961, the company made important improvements in AM-FM stereo tuner design, and it increased the power and improved the sensitivity of its components.
 Frequency response: 20Hz-20KHz.){kind=link}