Schiit Magni 3+
Magni 3+ and Magni Heresy raise the bar even higher for affordable headphone amps, with by far the highest output power in their price class–at least 200% higher than any competitor. At the same time, they provide the cleanest measured performance of any Magni, ever.
The Marantz HD-DAC1 is a stylish compact DAC and headphone amp that comes with USB and analog 3.5mm in. Though it does not have the best specs when it comes to audio decoding capabilities, it's a great sounding device.
24 bit / 192 kHz
20 Hz - 20 kHz
Cirrus Logic CS4398
Audio Science Review
The Magni 3+ is also very competent amplifier and subjectively kept up with Heresy.