These microphones are very good already yet they don't quite compare to the top names in the game. Usually a few compromises have been made in the mic and in the power supply that prevent these mics from being their best (or comparing to the beloved classics). A few changes can bring them to a higher level of quality and refinement and change it from second-string into your 'go-to' mic. (Typically the capsule (and transformer where applicable) are of good quality, but I will advise on a per case basis when the microphone is in hand if the case is otherwise, and determine cost at that time.)

This modification includes the replacement of essential capacitors and resistors in the microphone, replacement of FETs where warranted (and HFE matched, where applicable), adjustment of EQ capacitor values to attenuate high frequencies if requested, new solid-core wire where warranted, and reconstruction of the headbasket as needed or requested.