These pictures and text borrowed from http://www.audioimprov.com/AudioImprov/Mics/Entries/2013/2/26_AKG_Perception_220.html
They are designed to be used for study purposes for the amplifier subjects in the electronics course, especially the FET section. (Luciana Zogbi) … powered by AKG Perception 220! Chinese mic for a top performer and performance!
Note the Phantom power +48 Volt input which is then isolated by an output transformer. An old design but a classic design.
I doubt whether the output transistor is PNP emitter follower as the FET stage has only a voltage gain of about 3.0 so more voltage amplification is needed to drive the output transformer, so likely there are some small problems with the supplied schematic here….. but great for training and discussion purposes.
I have tried one of these mics and was very impressed with the midrange for voice… kind of like a telephone response curve to the human ear. Obviously it did not tail off at 5khz… but something in it’s sound gave that impression. Maybe just the bass cut in the circuit.