+ High power, capable of driving a wide range of loudspeakers. + All-tube full preamp line stage, with buffered pre-out and regulated B+. + No-load automatic shutdown in headphone circuit. + Front panel selectable direct amp in / processor loop input. + Built-in upgrade path for precisely gain-matched horizontal biamping with VTL ST-85. + High quality VTL ST-85 power supply components and output and power transformers. + All hand-built in the VTL California factory.