121
The Tektronix 121 is a wideband preamplifier intended for 511 scopes. The voltage gain is 100, input impedance is 1 MΩ in parallel with 25 pF. The frequency response is 5 Hz to 12 MHz. It has an unbalanced signal path with switchable compensated attenuators before and after the first gain stage, a 6CB6 common-cathode amplifier. The 1121 can be considered the successor to the 121.
Comparison of 121 and 112
The 121 and 112 are both standalone amplifiers produced by Tektronix in the 1950s. A comparison shows their differences.
121 112 Bandwidth 5 Hz to 12 MHz DC to 2 MHz Voltage Gain 100 5000 Year of Introduction 1950 1950 Weight 18 lbs (8 kg) 32 lbs (15 kg) Price in 1950 catalog $265 $495 Front View 
Manuals
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Block diagram
