S-420.2 SEDONA SERIES AMPLIFIER Anybody who thinks that quality was lost when the old school products died is foolishly mistaken! Anything that involves technology advances over time. Newer materials, new engineering techniques, and technology itself. The Power class amplifiers clearly represents what audiophile quality car audio should be. Unparalleled sound quality stems from multiple factors; top quality torroidial transformers, all N-channel transistors, extremely low tolerance resistors and capacitors, and so forth. The preamp section is extremely detailed with 4 different types of crossovers: high pass, low pass, band pass, and subsonic. And just to be sure that the amplifier's output is not ruined by cheap or noisy input signals, we included balanced line inputs to be used with our BLT transmitters for the ultimate listening experience!