A cheap Chinese preampboard based on PGA2311, a nice display and remote control. Add a tube buffer and it's all done.
I did build a preamp for a guy as a compensation for a stalled project.
The tube was added as the chip, PGA2311, hasn't the drive capacity need in some case. Btw, the tube amp is a cathode follower.
Parts are bought from Chinese shooping portal, AliExpress. It can be tricky to buy stuff as prices can be given with or without Free Shipping. I noticed that chassis may be very cheap, but shipping may often double the price, but in this case the chassis came pretty cheap - including shipping.
Note the schematics are more or less just examples how things may have been done