Siemens U274 Talkback Mic Pre, used, checked

Siemens U274 microphone / command amplifier, used, tested

The discrete Siemens U274 is a command amplifier with an integrated limiter that can be switched on and off from the front.
The input and the output of the command amplifier are floating.
Furnishing
Behind the front panel - visible on the front - is the switch for switching the dynamic limiter on and off
After removing the plastic toggle, the slot axis can be turned with a screwdriver to the right (limiter switched on) or to the left (limiter switched off).
The gain can be gradually adjusted on the front to 44 - 50 -56 - 62 - 68 - 74 dB.

Gain 44-74 dB ± 1 dB
Frequency range 40 to 15000 Hz
Deviation from the linear frequency response without limitation
40 Hz 0 ...— 2dB
120 to 15000 Hz ± 2 dB


with limitation (74 dB gain)
40 Hz> 15 dB
300 to 5000 Hz ± 1 dB
15000 Hz about - 5 dB
Limiter:
Attack time 10 ms
Release time 0.5 s