The STX 100D is the latest product to be available from Spectra 1964. Based on the Spectra Sonics console design and development from 1964 through 1971, the 100D features an all-discrete topology using two 101 amplifier modules and US-made input and output transformers, packaged in a single space 500 series lunch box format. Without compromising performance, the 101's were reduced in physical size by over 75% to fit the 500 series lunchbox.