I just re-did my Monica 2 DAC.
It used to be paired with a grounded grid 6688 that somebody at PDVD did for me. The sound from the DAC and the 6688 grounded grid is sort of bitin, so I installed new PSU with better pi filtering and the 6688 grounded grid using plate chokes, which was called for in the original design. The original PSUs B+ also sags under load and it made the sound kind of flat. After my modification of the PSU, the sound opened up!
Yeo (the designer of the Monica 2 DAC) emailed me and told me there is a new I/V linestage that sounds better than the 6688 grounded grid. So I purchased the PCB and assembled the RB SS I/V stage. I dismantled the 6688 grounded grid and junked the original chassis.
I completely redesigned the PSU, opting for better regulation and better filtering using Aerovox caps and wima polypropylene on the PSU for both the DAC and the I/V stage.
I just finished the soldering at around 9:00 pm last night:
The DAC is on the left side top shelf, the tubed preamp on the right top shelf is a 12au7 cathode follower, inspired by the Foreplay 3 design, using 0D3 regulator and well filtered PSU. On the lower shelf is my 832A PP amp driven by a 6J5.
It sounds glorious, my vintage Philips DVD player connected to the Monica DAC sounds better than a tubed CDP!
This weekend, I will sand the wood plinth, use tung oil for finishing, for the alum top plate, I will coat it with baking type automotive clear (from my work at Nippon Paint).
