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3A74: Difference between revisions
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==Internals== | ==Internals== | ||
Each input signal passes through switchable input attenuators and then into a cathode-follower | Each input signal passes through switchable input attenuators and then into a cathode-follower | ||
made from a [[7586]] Nuvistor triode | made from a [[7586]] Nuvistor triode driving a PNP differential amplifier. The output of this | ||
differential amplifier, for each of the four channels, passes through a diode-based | differential amplifier, for each of the four channels, passes through a diode-based | ||
analog signal switching network (multiplexer). The output of that multiplexer drives the output amplifier, | analog signal switching network (multiplexer). The output of that multiplexer drives the output amplifier, | ||
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The 3A74 uses Tek-made 185-ohm [[potentiometers]] in for the VAR GAIN controls. | The 3A74 uses Tek-made 185-ohm [[potentiometers]] in for the VAR GAIN controls. | ||
These can be a [[:Category:Repair_issues|maintenance issue]]. | These can be a [[:Category:Repair_issues|maintenance issue]]. | ||
The 3A74 contains a total of eight 7586 [[Nuvistor]]s. | |||
==Links== | ==Links== | ||
* [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_other/3A74.htm Tek 3A74 @ amplifier.cd] | * [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_other/3A74.htm Tek 3A74 @ amplifier.cd] | ||