1967 Harmony 525

This is a used Harmony 525 vintage tube amplifier with two 6L6GC power tubes and a 15-inch speaker, manufactured by Valco in the USA. Valco also made amps for Supro, National, and Airline.
The Harmony 525 (e.g., a 1967 model) is often tonally similar to the Supro Thunderbolt S6420, sharing a preamp design, tube complement (around 35 watts), and a 15-inch Jensen speaker. These amps are prized for rich clean tones, wooly rhythm sounds, and saturated tube overdrive.