You should look into Don Sachs SP14 preamp. You could get his pre with all the upgrades for a lot less than $3500.
Preamp Upgrade
I have a Herron VTSP-1/166. Sounds great. Looking for better. I don't know a lot about preamps. I had been using a passive for years until I bought and Herron VTPH and found that they work best often with Herron preamps. Now I've found another phono stage I love and I'm thinking about upgrading the pre. Is there something incredibly simple (I'm vinyl only) that is an upgrade to what I have? Or have preamps not become better for the buck in the last 7 years and it's going to cost $3500 to improve on what I have?