We know the importance of this device, which has always been used in various audio circuits. It is not only used in DACs, but also in preamplifiers, mixers, equalizers and crossovers, musical instrument effects, etc. Well, this project is well-established, in the sense that I created it several years ago and it has been used in many fields with excellent results; we even re-OPed a studio mixer. The first version was made with SMD components, for purely production reasons. Today I'm showing you the revised version with fully discrete components, meaning "through-hole" assembly, so it can be assembled by hand. The circuit remains the same, but I've implemented some improvements that I believe to be beneficial. For example, the two input transistors, which determine the differential gain, have been mechanically coupled to further improve temperature coupling. The use of discrete components allows us to choose transistors with manually matched noise and gain characteristics, which are impossible to achieve with a standard SMD assembly. Furthermore, given the simplicity of the circuit, it is possible to 'try' transistors of different types, for example germanium ones.