What Headphone Amp or Amp specification do you recommend for the HEDDphone?
The HEDDphone rates 87dB SPL for 1 mW @ 1kHz. The linear impedance is rated at 42 Ω. To allow the AMT to fully unfold its capabilities, we suggest to allow for enough headroom and recommend at least 1,5 watt to power the HEDDphone without limitations. Your experience may vary depending on the loudness you use.
Personally, our team enjoyed using the HEDDphone with any of the following gear: ifi Audio Pro iCan, RME ADI-2 DAC/Pro, SPL Phonitor 2, and many more.