The Bellari PA555 is an all-analog 4-channel tube preamp. It adds a warm tube sound, thanks to the 12AX7 tube, to any line level input source. The front panel features (3) stereo RCA inputs and (1) 1/8' input. There's a rotary input selector and volume control for easy operation. It has gold-plated RCA inputs, outputs, and a grounding connection. The metal casing comes with vibration damping feet. The PA555 uses a 12AX7 tube running at 150 volts. The input signal connects directly to the tube's grid, and all the gain is from this tube. The output section has a pair of emitter followers. It has no feedback circuit or integrated circuits in the audio path, making it truly all analog. Key features include a 12AX7 tube, 3x RCA stereo and 1/8' TRS stereo jack inputs, RCA stereo output, 10K ohms input impedance, 11.1 dB max output gain, 0.1% THD, 103 db unweighted S/N Ratio, 5 Hz – 198 KHz +/- 3 db frequency response, -75 dB crosstalk, 100 Ohms output impedance, dimensions of 6' x 2.5' x 5.4' / 15.9 x 5.1 x 17.1 cm, and a weight of 2 lbs / 900 g. It comes with a power supply.
Using the Bellari PA555 tube preamp is quite straightforward. First, connect your input source to one of the available inputs on the front panel - you can choose from the 3 stereo RCA inputs or the 1/8' input. Then, use the rotary input selector to pick the input you've connected. Adjust the volume control to your desired level. You'll start to enjoy the warm tube sound added by the 12AX7 tube. When it comes to maintenance, keep the preamp in a clean and dry place. Avoid exposing it to extreme temperatures or humidity. If the unit gets dirty, use a soft, dry cloth to gently wipe it. Also, make sure to use the provided power supply to ensure proper operation. And remember, since it's an all - analog device, handle it with care to avoid any damage to the internal components.
