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The second microphone I will take under the magnifying glass is the stabo Optimike.
The stabo Optimike was a base station dynamic microphone with amplifier, no compression.
This one was manufactured in the 70’s by Altai of Japan and was also sold under the name of Leson piezo DX-354. To respect the law in Germany at that time, this mic doesn't have a lock switch, could be annoying. The original Leson model had a lock.
 “Nutrition facts”
Year : 1990
Type of microphone : Dynamic
Microphone characteristic : omni directional
Sensitivity : -30dB (0dB = 1Volt/microbar)
Nominal output : 371mV
Max output :
Output at mid range : 106mV
Frequency response : 300Hz - 4kHz
Output impedance : 1.2KOhm.
Amplifier voltage gain : 30dB
Compression : no
Meter : No
Echo : No
Lock switch : No
Tx LED : Yes
Battery : 9V
Remarks, -30db (0dB=1Volt/microbar) is a quite old reference system used mostly by non european manufacturers. -30dB(0dB=1Volt/microbar) is equivalent to -10dB(0dB=1Volt/Pa) the now used reference. This means that if you speak loud (not cry) in your microphone from about 2 inches a distance you should get 316mV(max output) at the output of the microphone (at 1KHz and 600Ohm load) . I measure 371mV with a fresh battery, so above specifications.
My opinion, a very good microphone with a very clear and well-balanced modulation, silent pedal switch, full metal jacket. I’ve noticed on the scope a very little distortion at level above position 8, this distortion was not to be heard. This microphone is as good for DX-communications as for local FM or AM rag-chewing.
Around 1991 a second version named Optimike X appeared, I never owned this model and have no informations about the differences (if any) between the first and the second model to share.
Seen price: 20€ (poor conds) to 90€(mint to mint boxed)
My opinion : 3.5 stars from 5
Listen to the Optimike sound (potentiometer at mid range, 106mV).
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