assuming the output is AC coupled.
Using a LM741 is possible, I think one transistor can make it much easier. Controlling pulse amplitude can be made by a "volume control" potentiometer e.g. across the output (5-10 kOhms)
I am looking for one shot pulse output not ac sine wave.
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As per one of my friends suggestion-----
The pot in parallel with the load in the first circuit will not give the required variation in pulse amplitude.
The 741 opamp has an output current of ~25mA max; not enough to drive those loads.
Neither circuit has a way of stepping the output level.