An Archival Phono Preamplifier is a phono preamplifier designed for playback of vintage recordings long-playing, 45- and 78-rpm records made before the RIAA curve was universally adopted by the recording industry. Broadcast transcription discs normally 16-inch lacquer discs recorded at 33 1/3-rpm also fall into this category, as do cylinders. Prior to the standardization of the RIAA curve for long-playing (33 1/3-rpm) records in 1956, the equalization curves used to cut phonograph records varied widely among recording companies. Engineers were sometimes known to change curves from one recording session to the next and, on occasion, from one side to the next in a multi-disc 78-rpm album. To help music lovers sort out this confusion, High Fidelity magazine regularly published a page called Dialing Your Discs, which offered recommended playback settings for most American Lp record labels. Although there are some (expensive) commercial preamps available with customizable replay characteristics, Gary Galo found them wanting and has over the years developed a phono preamp designed to replay all these different formats and recording curves. That design is described in this article.
An Archival Phono Preamplifier