I used Audioquest Opal x3 with good results. Later, I went to TARA Labs Master Gen 2, which worked a bit better, with a larger soundstage, but just barely not as accurate, perhaps a bit more foreward. Next, I used Audioquest Lapisx3, which is even better, smooth smooth smooth with detail galore, all without "sounding" like anything. Lastly, the Audioquest Diamond x3, which is simply amazing, more bass than Lapis x3, possibly more speed, just a hair less laid back, and tonally on the money.