I haven't heard the Doshi v3.0 preamp but I own v2.1 and it was the direct replacement of my previous preamp, the Audio Research Reference 3. For what it's worth, below are some of the sonic qualities (from what I remember) I noticed during my the Doshi v2.1 vs ARC 3 comparison. Both had good...
I own the Doshi 2.1 phono separate and I think it is fantastic. I'd owned the ARC PH7 (with power supply upgrade) and Lamm LP2.1 Deluxe prior to it and the Doshi was far better than either of my previous in all sonic senses that I can think of... This isn't going to help in your Wyetech Ruby...