Recently I was at a resale store that the student I tutor and I visit every so often. I found some highly priced 78s but they were too interesting and produced from a Spanish "branch" of Victor. One of them was this box set, a very early collection of raw conga that couldn't have been released later than 1940. It is a Victor box set, collecting several of their label's 78 releases.
Artists included in the box set: Oscar de la Rosa, Orquesta Casino de la Playa (a group I was familiar with before), Orquesta Havana-Riverside, and Conjunto Melódico Cubano.