The PSS 390/380 has the vastest realtime FM synthesizer I've ever seen in a home keyboard or FM synthesizer. Each of the 100 FM preset sounds can be massively changed in terms of timbre, frequency, vibrato intensity and envelope via seven 10-step slide controls, making extreme FM sounds possible. Additionally, 2 sounds can be layered. The auto accompaniment also holds 100 interesting patterns.
Through my modifications, sounds can be altered even more drastically, enabling very noisy and atmospheric output. At the touch of a switch, the anyway already fantastic auto accompaniment styles transform to completely new variations and loops, surprising me again and again. A cool machine which is often for sale at ebay.