This is premium version of my old DAC AH-D6 (2 Layers PCB). The new DAC is made on an improved 4-layer printed circuit board. AH-D6.1 has improved the power supply regulator and analog filter circuitry. DAC has ultra-low harmonic distortion.

• AK4493 - 32-bit Stereo Premium D/A Converter DR, S/N: 123dB, THD+N: -113dB
• PCM up to 384KHz/32Bit
• DSD/DOP 64,128 and 256 
• I2S input (master and slave mode), 2x5 Pin - 2.54mm connector
• 2 scales (44.1x/48x) MCLCK oscillators on board (NDK femto clocks)
• 11 Super Low-Noise voltage Linear Power regulators
• AK4493 VREF Ultra–low noise Linear Power
• Hardware Relay Mute at the outputs
• Microprocessor based control
• Sharp/slow roll-off filter switch (jumper configuration).
• THD < 0.0001%, THD+N < 0.0002%
• Board size is 69x100mm, 4 layer PCB

More Details: http://audiohobby.ru/articles/vysokokachestvennyi-cap-ah-d6-1-na-ak4493-ak4490-premialnaja-versija-ah-d6.html

Recommended Interface Board (USB-I2S):

https://www.pcbway.com/project/shareproject/Combo384__Amanero____I2S_isolator_v1_5.html