AD1862 is a 20 bit R2R DAC made in the same period of PCM63 by Analogy Device. This chip size is small using DIP16 package. The performance of this chip is also outstanding but this DAC was not so widely used in CD Players relative to PCM63 in the past.
To use this chip, the DAC analogy supply of D1 need to be at +/-12V and the digital supply can be remained at +/-5V in the D1V3 or D1V33 board. To change the analogy supply to +/-12V, 4 resistors has to be remove and re-solder from 300 to 850 ohm (I use 750 ohm + 100 ohm). The designation of the 4 resistors are R105, R109, R126 & R127. Besides the resistors change, the capacitors of the analogy supply has to be ensure using 16V or above capacitors. I have 8 pcs 6.3V blackgate on the board and thus I have to change them to 22uf 16V Duorex capacitors.
Since AD1862 is not pin compatible with PCM63 and thus I have to hard wire 4 converter boards as shown on the pictures. The pins that connect to PCM63 sockets are Pin 2, 6, 7, 11, 12, 13, 18, 20, 21, 28. The two E-caps (1u and 12u) on the board is for AD1862 filtering and Red wima is 0.1u for power supply decoupling. This is a bit time consuming but it is a cheap way to test out how AD1862 perform in the D1 platform.
The result is quite satisfying as the AD1862 also sound very good. It has darker sound due to its strong bass (good current source driving capability using +/-12V supply). The distortion is also lower compare to PCM63 in D1 platform due to its lower +/-1mA output range. Noise floor is better than PCM63 a bit (1~2db) as seen in the FFT measurement. But there is more high frequency odd harmonics when input is at 20bit/44.1k at 0 or -80dbFS.
All measurements are in balance output mode unless otherwise specified.
FFT DAC D1V3 AD1862 vs PCM63
FFT DAC D1V3 AD1862 @ -80dbFS 16 vs 20bit
FFT DAC D1V3 AD1862 Single end output
FFT DAC D1V3 AD1862 Balance output 0dbFS log
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