Bicycle Recordings 312 Hybrid Preamp

Projects > Bicycle Recordings 312 Hybrid Preamp

The 312 Hybrid PCB provides a platform for DIYers to build an API 312 or John Hard M1-type circuit using their own opamps and transformers. This PCB is great for those who want to experiment with different transformer and DOA circuits, or for those who have prized components lying around collecting dust.

Notable Features:

  • PCB-mount jacks and switches designed to fit in an 8” deep case
  • Accepts five types of input transformers:
    • Jensen JT16A
    • Lundahl LL1538
    • Cinemag CMMI-2C (threaded bushing model),
    • OEP A262A3
    • Standard 312 type (2503)
  • Option for DC servo or transformer output
  • Accepts 990/2520 footprint opamps
  • Designed for 12-position Grayhill gain switch
  • Eight or more fit in a 2RU chassis


  • $29 for version 3.1 PCB

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