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Modular HP Amp 2017

by nihtila
  • Modular headphone amplifier based on HP MoBo motherboard and changeable amplifier daughterboards:
    • HP TPA – simple TPA6120A2-based amplifier
    • HP Buf – BUF634- or LME49600-buffered amplifier
  • Balanced input
  • Balanced and unbalanced headphone output
  • Output mute circuit
  • Part of multi-component system with external power supply


Modular HP Amp 2017 is based on HP MoBo encased in a snuggly fitting aluminium case along with custom-made front and rear panels to give tidy finish. Different amplifier daughterboards can be used on HP MoBo to experiment with various amplifier circuits without re-designing everything.

To find schematics, detailed design descriptions, and performance measurements, see corresponding posts:

Modular HP Amp 2017 and two amplifier boards

The aluminium enclosure is from eBay and panels are custom-made from Schaeffer AG. PCBs are from Elecrow.

Modular HP Amp 2017 front

Modular HP Amp 2017 rear

HP system

This amplifier has been part of my desktop headphone setup for six months or so (hence 2017 and not 2018). The system consists of four components to allow upgrading single components in the system or experiment with different devices.

Four-component HP system

The components are new version of PSU Pre 2016 , modified HP Pre 2016 (only H-DAC and Addon BalOut without preamplifier addon), BHT Preamp (to be published) and Modular HP Amp 2017. More information regarding BHT Preamp and modified components coming soonish.

HP Modular Amp 2017 as well as other components are powered by DIY PSU with custom cabling providing analog and digital supplies.

PSU Pre 2017 and 4-pin custom power cables

Currently my main headphones are Hifiman HE-560 with DIY 2.5mm – XLR balanced cables.

Hifiman HE-560 with balanced DIY cables

Balanced headphone amplifiers are not very common and existing ones usually have 4-pin XLR connector. However, few have dual 3-pin XLRs and I wanted to have those as well to maximise separation between channels. Note that XLR gender in headphones is opposite to common convention.

Version history


  • No changes since initial version

This page version history

  • 4.2.2018 Initial version

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