For sale is a vintage RCA channel strip that someone was turning into a XFMR balanced mic pre. It has an original API 2520 op amp made for RCA. It also features a RARE Painton fader found in Vintage EMI audio consoles in the late 60s. This would make a great project for a hobbiest or professional and won't be hard to finish with some time and effort.
At the end you would get an awesome preamp with a Painton fader! Please message with any questions. I also have some schematics that I will include with it necessary to get the unit operational.