36,375
edits
122: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
| (3 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
{{Instrument Sidebar | |||
|manufacturer=Tektronix | |||
|model=122 | |||
|class=Amplifier | |||
|series= | |||
|summary=low-level preamplifier | |||
|image=Tek 122 x.jpg | |||
|caption=Tek 122 early model | |||
|introduced=1950 | |||
|discontinued=(?) | |||
|designers= | |||
|manuals= | |||
* [[Media:070-246.pdf|Tektronix 122 and 125 Manual]] | |||
* [https://w140.com/brophy_122_mod.pdf Low Noise Modifications of the 122] | |||
}} | |||
The '''Tektronix 122''' is an external low-frequency low-level preamplifier. | The '''Tektronix 122''' is an external low-frequency low-level preamplifier. | ||
| Line 12: | Line 27: | ||
The second stage is a [[12AU7]] differential amplifier, differentially driven by the first stage. | The second stage is a [[12AU7]] differential amplifier, differentially driven by the first stage. | ||
There are DC blocking capacitors between plates of the first stage and the grids of the second stage. | There are DC blocking capacitors between plates of the first stage and the grids of the second stage. | ||
The second stage is coupled to the third stage by capacitors, | The second stage is coupled to the third stage by capacitors, which can be switched to select the low-frequency cutoff frequency. | ||
which can be switched to select the low-frequency cutoff frequency. | |||
The third stage is a common-cathode amplifier formed from one half of a 12AU7 dual triode tube. | The third stage is a common-cathode amplifier formed from one half of a 12AU7 dual triode tube. | ||
The plate load resistors of the third stage amplifier are shunted by switchable capacitors, | The plate load resistors of the third stage amplifier are shunted by switchable capacitors, allowing the high-frequency cutoff to be selected. | ||
allowing the high-frequency cutoff to be selected. | The resulting signal is buffered by a cathode-follower stage formed from the other triode in the third stage's 12AU7 tube, biased at 1.8 mA plate current. | ||
The resulting signal is buffered by a cathode-follower stage formed from the other triode in the third stage's 12AU7 tube, | |||
biased at 1.8 mA plate current. | |||
The output impedance is rated to be about 1000 Ω. | The output impedance is rated to be about 1000 Ω. | ||
| Line 41: | Line 53: | ||
* RM122 (rack mount, horizontal orientation, with wide front panel for mounting mounting in a standard 19" rack, later called "R122") | * RM122 (rack mount, horizontal orientation, with wide front panel for mounting mounting in a standard 19" rack, later called "R122") | ||
* FM122 (frame mount, vertical orientation, for use in the [[014-002]] mounting frame, later called "F122") | * FM122 (frame mount, vertical orientation, for use in the [[014-002]] mounting frame, later called "F122") | ||
==Pictures== | ==Pictures== | ||
| Line 62: | Line 70: | ||
Tek 122 system rs 1.jpg | Tek 122 system rs 1.jpg | ||
Tek 122 system rs 2.jpg | Tek 122 system rs 2.jpg | ||
Tek fm122 front.jpg|Tek FM122 front | |||
Tek fm122 top connector.jpg|Tek FM122 top power connector | |||
</gallery> | </gallery> | ||
==Components== | |||
{{Parts|122}} | |||
[[Category:Amplifiers]] | [[Category:Amplifiers]] | ||