Pro-Ject Pre Box RS Preamp The Pre Box RS is a reference-grade 2-channel preamplifier featuring a fully balanced dual-mono design with a vacuum tube based output stage. The circuit design is both ultra quiet and highly linear using no global negative feedback. Operating in pure Class A the Pre Box RS is capable of producing stunning musical realism from any line level source. There are numerous source connectivity options using either two pairs of balanced XLR"s or the three paisr of single-ended RCA jacks. High-quality component parts are used throughout including low ESR capacitors, rugged relays, reliable dip-switches and a motor driven Alps potentiometer to control output level. All circuitry is encased in a heavy and rigid aluminum chassis that is mechanically constructed using anti-microphonic techniques. A robust highly regulated and filtered outboard power supply delivers ample voltage for impressive dynamic capabilities. An IR remote control is supplied.