Plenty of audio DIYers have discovered what an excellent modding base the DAC-AH Lite is. I'm a latecomer to the party, but better late than never here's my contribution to the art of DAC-AH-alikes.
Most of the mods I've seen focus on the output stage, some upgrade the PSUs. Here's yet another variant - change the DACs. The TDA1545 is pin compatible with the TDA1543 so I swapped out 8 TDA1543s and replaced them with 8 DAC-stacks made up of 5 TDA1545s each. 32 DACs in parallel produce the normal NOS output, the additional 8 DACs are fed from a two-stage delay line (16 74HC595s) to correct for the zero-order hold. I/V conversion is done passively and differential - 1.3ohms in each polarity. The post I/V stage is a pair of AD605s giving a true differential output. In between the two is a passive filter made up of TDK ferrite beads and NP0 capacitors.
How does it all sound? - well of course one is always biassed when describing one's own offspring, but in a word...