Fiio a5 portable headphone amplifier for iems and headphones fiio has strived to constantly progress and innovate with fresh ideas in the portable amplifier market since its own entry with the a5 headphone amplifier they continue this tradition by striving to significantly improve over our previous products the e12 series every last detail of the e12 series has been reworked and revamped so as to create a new headphone amplifier that not only maintains the e12 series strengths but also rises a