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.
Nagra distributor John Quick demonstrated both options for me, using the new version of Verity Audio's Sarastro speakers driven by Nagra's pyramid-shaped class-D amplifiers and a front end comprising a Basis turntable and arm fitted with what I noted was an EMT MC cartridge. The presentation was more robust-sounding with the solid-state output, with more authoritative low frequencies, but the soundstage was better defined, more delicately delineated, with the tube output. Mikey Fremer is scheduled to review the VPS.