The PPA is an audiophile-quality, DIY headphone amp designed by “Team PPA,” made up of HeadFi.org members Tangent, ppl, and Morsel.

Notable Features:

• Compatable opamps:
• AD8610
• OPA627
• OPA134PA
• AD843
• Switchable bass boost
• Optional NiMH battery board for portable operation
• LED Battery indicator

Price: $18 for PCB
More Information:

• The official Team PPA page.
• Tangent’s PPA Page, including build notes and BOM.
• Parts available from Tangent’s online store