Hi all,
Don Sachs here. I just want to clear something up. Yes, you can buy a kit from Roy and build a great preamp. I use the same board. I suggested a number of improvements to that board and now kit builders can have them. That said, my preamp will be 25% or more better than the kit. The only thing my preamp shares with the kit is the bare board. All parts choices are mine, I have changed the operating point of the tubes, I have improved the power supply considerably, etc... I have my recipe that has been worked out over 4-5 years. That said, if you build a kit you will get a wonderful preamp for very little money and have the satisfaction of building it. If you get one of mine you get a warranty, and considerably better performance.
As for the other preamps mentioned, I am sure they are very good and the manufacturers take great care in building them. I cannot comment on their sonic qualities as I have not hear them.
cheers,
Don