The Bellari PA555 is a hand built tube (12ax7) preamplifier. With four selectable stereo inputs; 3 RCA on the rear and one 3.5mm (1/8") jack on the front. Hard wired power switch on the front. Gold plated RCA outputs on the rear.

The PA555 uses a 12AX7 tube running at 150 volts. The input signal is connected directly to the grid of the tube and all of the gain of the PA555 is from the 12AX7 tube. The PA555 has a no feedback circuit or integrated circuits in the audio path, it is all analog.