This is a great preamp kit designed by Nelson Pass, comes with exceptional quality parts, and easy to build. The Korg Nutube 6P1 tube is not just a very cool device to look at, but also a very low power consumption vacuum tube which made it a perfect solution to convert it as a battery-powered preamp. Unlike a regular vacuum tube preamp, the Nutube 6P1 is not interchangeable. Although tube rolling is not possible to this preamp, Nelson adds a feature to adjust audio harmonics by a pair of trimmer pots each controlling the left and right separately. I can experience a different sound stage and 3D space by adjusting the value of the trimmer while the amp is powered on, how wonderful!
The kit already comes with audio grade electronic parts. Chassis is simple but elegant and solid, high-quality parts from Italy. I completed the kit with original parts which sounds very good already, later changed a few electrolytic caps with some polypropylene from the signal path suggested by the group member, this further improved the sound quality.
This little preamp kit is easy to build with lots of fun to discover. Worth every penny!