I find it exciting to discover a nice audiophile amp from a nondescript brand. In this article, I chronicle my rebuilding of a PACO preamp-amplifier model SA-50.
PACO is the Precision Apparatus Company, best known for building quality test equipment such as tube testers, signal generators, and oscilloscopes. The “PACO” branded gear (as opposed to gear that used the full name of “Precision Apparatus”) was sold as a build-it-yourself kit. During this rebuild and subsequent troubleshooting, I found two connections that were never soldered, and one loose solder joint. Those issues are extremely common to find when servicing vintage kit-built gear.
I do not have any paperwork or background information about this model. I did find a schematic for a model SA-40, which appears to be largely the same circuitry.
The SA-50 is a stereo preamp-amp with these design provisions: (more…)