1A2: Difference between revisions

122 bytes added ,  6 December 2020
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1A1 and 1A2 share some mechanical design, but the circuits have few details in common.
1A1 and 1A2 share some mechanical design, but the circuits have few details in common.


The 1A2 uses a [[7586]] [[nuvistor]] at the front end as a cathode follower.
Below serial number 11000, the 1A2 uses a [[7586]] [[nuvistor]] at the front end as a cathode follower.
Then one input of an NPN differential amplifier is driven to produce a differential current-mode signal at the collectors.
Above serial number 11100, the front-end uses a FET for this function.
After the front-end buffer, one input of an NPN differential amplifier is driven to produce a differential current-mode signal at the collectors.


Silicon diodes form an analog multiplexer that switches between the two inputs.
Silicon diodes form an analog multiplexer that switches between the two inputs.