@ James,So you have used some of these Chinese mic boards successfully. I’m curious whether yours have missing bass like the ones I’ve seen. For radio or speech recognition, that might be a good thing, actually.The green boards inside these lollipop mics work OK after adding a filter cap (blue electrolytic in photos), but output polarity is wrong for studio use, requiring trace cuts and jumpers to swap pins 2 & 3. These boards don’t have the phase inverter problem.
The main description of the Universal China Mic circuit is here:
It actually works well after fixing the noise from the voltage regulator. You can improve performance by selecting very low noise transistors, audiophile capacitors, etc. but the generic parts come within a dB or two and are good enough for studio use. If I were magically to be recording Taylor Swift or Sting’s vocal track, I’d pick a mic made with those audiophile bits, tho.
One guy (Why is it always?GUYS who build microphones?) fixes his pencil mic boards by flipping the offending PNP transistor over and rotating it so the connections line up. One batch of boards was laid out so it was possible to cut traces to emitter and collector and solder tiny jumpers in place. Whatever works.
The other board probably is based on something like a MAXIM MAX4466 preamp chip. Most studio recordist types will sneer at these, but considering they run clean guitar and organ tracks through guitar amps and mic the amps with their U87s, and collect all sorts of stomp boxes, I’d say anything goes in the studio as well.
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Henry
