Hi,
I know about 2 serious vendor : Little diode ; Rochester Electronics. This last sell K grade at 52 dollars, but 5 pieces minimum order ! I need just one
If you talk about the Raindrophui 1865 Dac, I assume you have the 2 chips version without output stage. I have the one chip version with discrete stage (passive i/v).
Near the Dac chip, i leave the 3 tantal caps to solder them beneath the ad hoc FM caps. I leave the 3 green Vishay MKT. For the 2 analogs caps I put 22 uF KS Muse (no little decoupling). For the digital cap I test : 1 uF paper X2 mkt or 1 uF MKP, or 47 uF Oscon, or 22 uF nichicon HD, or 3,3 uF Wima MKS-4 (mkt). No ceramic, no silmicII, no tantal (but the 11 uF tantal moved under the FM cap near its reg).
I had acceptable success with that, but I follow too the advices found on DIYA about this chinese DAC: bypass the spidf transformers (Lampizator mod) and serie caps for the input on the CS chip, follow the constructor value with resistor and cap (670 nF & ...rtfm). I try 250R for passiv i/v and i plan to try it now with wirewound Rohpoint or Mills.... I remove too the 2 DC bloking caps and maybe will buy a true K grade, which imho is the last to do. I follow the advise of Abraxalito to play first with the layout... I assume a discret shunt like you do could be a great improvment...
cheers