Add 470 Ω resistor and 1000µF filter cap to quiet voltage regulator.

Move K596 FET to back of capsule and rewire as follower with 4.7KΩ load resistor.

This reduces capacitive load on capsule for more sensitivity.

Since FET does not invert signal, output is in phase with studio mics, and it isn’t necessary to swap wires to pins 2 & 3.

Pictures of the modded mic:

How does it compare with the charge amp version? (The beginner’s mic?) It’s more sensitive and detailed on first impression. It feels more lively, but that may be just because it’s louder. Loud always sounds better until it’s loud enough to hurt. It remains to be seen how this circuit stacks up against other variants of the Schoeps family of mics. The test will likely be drums and brass instruments to see how it behaves when driven near clipping.

All told, it’s a huge improvement over the stock BM-700 we started out with. The TSB-2555B capsule is a big step up from the small OEM capsule. Minor circuit mods quiet the hiss and tame the distortion of the Universal Chinese Mic circuit. Oddly enough, the circuit board itself is laid out for this circuit topology, but I’ve never seen a mic assembled with the correct parts. This would be a very low-cost mic if you start with one of the ZRAMO mics in the previous article.