FETboy Mic Preamp

Projects > FETboy Mic Preamp

In 2003, Scott Hampton, maker of Hamptone kits, published an article in TapeOp detailing a design for a simple FET-based DIY mic preamp. This design formed the basis for both Hampton’s beefed-up HJFP1 and HJFP2 preamp kits it’s cheap and cheerful cousin, the FETboy. “FETboy” is in fact nothing more than the name for Fabio Bauman’s PCBs using Hamton’s circuit. Bauman’s PCBs have long sold out, but FETboys remain a popular self-etch/perfboard project because they are rather cheap and easy to build. Their sound is often described as “woolly,” “harmonically rich,” “warm,” etc.

Notable Features:

  • Inexpensive / easy to build
  • Two FET gain stages (=lots of gain)
  • Transformer balanced

Price: no products available, etch your own PCB!


One thought on “FETboy Mic Preamp

  1. I built and racked up a quad channel box of FETboy pre’s. They’re great workhorse pre’s with decent headroom, and plenty of gain (I happily use a ribbon mic without cranking the gain too far). Couldn’t be happier with the sound. My other feature pre’s are a pair of valve channels I designed and built myself, based on a Jensen application circuit schematic.

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