TechPowerUp published a review on the iFi micro iDSD Signature Portable DAC/Amplifier
A quote from the article:
iFi introduces us to the world of premium portable DAC/amps with the aptly named micro iDSD Signature. It sports enough power to drive demanding headphones and yet can be configured to drive the most sensitive of IEMs too. We also get iFi's popular analog effects in the form of XBass+ and 3D+, this is a unit that seemingly tries too much, yet does everything fairly well.iFi micro iDSD Signature Portable DAC/Amplifier Review