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Pre and Headphone Amplifier project by Nelson Pass

ACP+ Amp Camp Preamp & HPA

The ACP+ or Amp Camp Pre + Headphone Amplifier is a wonderful first project for many DIYers. Some call it the Mini-J2. No chassis is required, and it can be built in an afternoon. If you're looking for your first Nelson Pass designed project, this might be for you.

ACP+ Amp Camp Preamp & HPA

Key Information

  • Pre and Headphone Amplifier Project
  • Designed by Nelson Pass
  • Beginner to Intermediate Difficulty
  • Complete Kit Available
  • Comprehensive Build Guide


  • Can be built in a day with basic tools
  • Excellent beginner's project
  • Can be tweaked to suit various headphone impedances as needed.


The is the ACP+ is a wonderful project for beginner's.  It an excellent first  DIY preamplifier and headphone amplifier.  People love it when paired with any of the the Amp Camp amplifiers to make a complete first-build system.  It doesn't even require a chassis.  Everything you need can be purchased in one kit and assembled in an afternoon.  The performance and sound are exceptional, as you'd expect from a Nelson Pass design.


Photos of Poet's DIY ACP+

The photo on the right (taken by Thuss + Farrell) is an ACP+ with all parts chosen, stuffed, and soldered by Patrick Farrell's 10-year-old daughter, Poet. It demonstrates the beauty of a completely do-it-yourself ACP+ with a colorful parts selection. 

Note - As mentioned, not all the parts shown in the photo are sold by the diyAudio Store.  Please review each product to see what's included in your kit.