Nagra Valve Phono Stage
In their suite at the Mirage, Nagra introduced the VPS (Valve Phono Stage), shown here under the Swiss company’s well-regarded PL-L line preamplifier. The front-panel switch selects between A and B inputs and mute, while the rear panel features two sets of inputs and outputs and an output level switch. The A inputs accommodate MC cartridges, while the optional B input can be set for either MM or MC operation. Capacitive and resistive loading can be changed with modules that plug into the pcb close to the input connectors. The MC circuit is based on high-quality transformers wound in-house by Nagra, followed by gain and RIAA stages using ECC81 and ECC83 tubes. The RIAA equalization can be set with internal jumpers either to the 1953 standard or to the 1976 standard. The circuit boards are mounted on compliant supports, to minimize microphony and the power supply is housed in a separate chassis. Unusually, the output can be taken either directly from the tube stage or via a solids-state buffer.