To celebrate Sennheiser's 75th anniversary they are offering a bundle consisting of the HD 820 as well as the HDV 820 desktop DAC/AMP at a 25% discount.
iFi's upcoming Hip-DAC is set to target the more budget-friendly end of the market and sports a number of features such as complete analogue volume control.
The output impedance of a player or amplifier is often overlooked, but in many cases it can make a great deal of difference to headphone frequency responses