SW1X Audio Design™ PRE III Performance Level 3 EL84 OPT Phono & Line Pre-Amplifier   The PRE III is a pure class A, zero negative feedback (global or local) line pre-amplifier with a signal output transformer (OPT) de-coupled valve output stage. Signal OPT of highest quality not only increases transparency (superior to any kind of … Continue reading SW1X PRE III Line Pre-Amplifier