04-11-2016, 02:48 AM
Here are some other references to this and similar kinds of amplifiers, sometimes described as “orthogonal”:
1954 November; Audio magazine; p.36ff; “Simplexing a Standard Amplifier for Two-Channel Operation”.
1958 November; Audio magazine; p.22ff; “For Stereo, The Bi-Ortho Circuit”.
1958 December; Radio-Electronics magazine; p.41ff; “2-Way Stereo Amplifier”.
1959 February; Radio & TV News magazine; p.41ff; “Simplexing for Low-Level Crossover”.
1959 February; Wireless World magazine; p.80; "Single-Amplifier Stereo”.
1959 October; Wireless World magazine, p.445; Brief description of the Emerson 502A record reproducer, which had an orthogonal output.
1960 February; Radio-Electronics magazine; p.44ff; "RCA’s 2-Way Stereo Amplifier”.
The above magazines are all available at: http://www.americanradiohistory.com.
The technique was also described in “Radio and Television Engineers’ Reference Book”, 4th Edition, 1963. See p.14-47, which refers to its use in some Murphy stereograms. The A674SR was one such model.
It appears to have had a small place in the early days of stereo, and in lower level equipment. One may see how an equipment maker who previously used push-pull outputs in say mid-level mono radiograms might baulk at the idea of having to use a pair of such outputs in similar level stereograms, and would have welcomed the orthogonal approach as a way of retaining some form of “push-pull output” claim without hugely increasing the valve-count. On the other hand it probably had little appeal to the hi-fi component makers, as it was likely seen as being a “hard sell” into a market of more knowledgeable consumers.
Within a short time though transistors arrived, with fairly early infiltration the mass market equipment. Given that transistor power amplifiers were mostly output transformerless, there was no place for the orthogonal approach, which used the output transformers for dematrixing.
The “Simplexing for Low-Level Crossover” was an interesting variation. It referred to what would now be called “bi-amping”, with an electronic crossover ahead of the bass and treble channels. But instead of separate amplifiers for each of these channels, a single amplifier was used orthogonally.
Cheers,
Steve
1954 November; Audio magazine; p.36ff; “Simplexing a Standard Amplifier for Two-Channel Operation”.
1958 November; Audio magazine; p.22ff; “For Stereo, The Bi-Ortho Circuit”.
1958 December; Radio-Electronics magazine; p.41ff; “2-Way Stereo Amplifier”.
1959 February; Radio & TV News magazine; p.41ff; “Simplexing for Low-Level Crossover”.
1959 February; Wireless World magazine; p.80; "Single-Amplifier Stereo”.
1959 October; Wireless World magazine, p.445; Brief description of the Emerson 502A record reproducer, which had an orthogonal output.
1960 February; Radio-Electronics magazine; p.44ff; "RCA’s 2-Way Stereo Amplifier”.
The above magazines are all available at: http://www.americanradiohistory.com.
The technique was also described in “Radio and Television Engineers’ Reference Book”, 4th Edition, 1963. See p.14-47, which refers to its use in some Murphy stereograms. The A674SR was one such model.
It appears to have had a small place in the early days of stereo, and in lower level equipment. One may see how an equipment maker who previously used push-pull outputs in say mid-level mono radiograms might baulk at the idea of having to use a pair of such outputs in similar level stereograms, and would have welcomed the orthogonal approach as a way of retaining some form of “push-pull output” claim without hugely increasing the valve-count. On the other hand it probably had little appeal to the hi-fi component makers, as it was likely seen as being a “hard sell” into a market of more knowledgeable consumers.
Within a short time though transistors arrived, with fairly early infiltration the mass market equipment. Given that transistor power amplifiers were mostly output transformerless, there was no place for the orthogonal approach, which used the output transformers for dematrixing.
The “Simplexing for Low-Level Crossover” was an interesting variation. It referred to what would now be called “bi-amping”, with an electronic crossover ahead of the bass and treble channels. But instead of separate amplifiers for each of these channels, a single amplifier was used orthogonally.
Cheers,
Steve
