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Power Amplifier project by Nelson Pass


The F5 is one of the earlier First Watt designs featured on diyAudio. At one time, the F5 was probably the most popular amplifier being built by diyAudio enthusiasts; a timeless design from Nelson Pass.



$ 25.00 USD
1 option

Key Information

  • Power Amplifier Project
  • Designed by Nelson Pass
  • Intermediate Difficulty
  • Only Essentials Kit Available
  • Comprehensive Build Guide


  • The Classic First Watt F5
  • Advanced DIYers can "tune" their distortion profile to taste

Links, Discussions & Files


The F5 is a Push-Pull, Class-A power amplifier. It is unique in that it has no capacitors in the amplifier circuit. The F5 is a voltage source amplifier, requiring nothing out of the ordinary from your preamp or speakers.

The F5 is probably the most popular amplifier being built on DIYaudio these days. It is simple to make, sounds fantastic, and has similar gain to many commercial amps.

Populate these boards with your components, then add your own power supply, chassis and heat sinks to complete the amplifier. The mounting hole spacing is the same as all other diyAudio Version 2 UMS boards.

Output power

25WPC into 8ohm

Power supply requirements

A Bipolar power supply of (+/- 24V) is required. The PSUs for almost all First Watt amplifiers including the F4, F5, F6, M2x, Aleph J, and Aleph Jzm are all essentially identical.

These Power Supply PCBs are suitable for all First Watt amplifiers.

Chassis suggestions

We have a full line of Deluxe Chassis perfect for this project. The two most common choices are the Deluxe 4U and the larger Deluxe 5U, however we heartily encourage you to consider the PASSdiy chassis currently available for pre-order until May 31st 2024. We also have a back panel parts kit to make life easier. Don’t forget the Keratherm.