SW1X LPU IV Phono: The ultimate level 4 phono stage

British company SW1X Audio Design has unveiled the ultimate SW1X LPU IV Phono tube phono stage 4, designed for high output moving magnet (MM) or moving coil (MC) cartridges. In addition to the fully balanced signal output transformer (OPT) design used in the LPU III, the LPU IV Phono circuitry is based on more powerful eight-pin tubes. Instead of the two amplification stages used in the LPU I, II and III phono stages, the LPU IV Phono has three amplification stages.


The input stage of the SW1X LPU IV Phono is based on two 6SJ7 tubes, an eight-pin version of the EF86 pentode. The intermediate stage is made on the popular 6SN7 double triode, and the output stage is powered by a pair of powerful 6F6 tubes.


In addition to the basic version ( £18k ), the SW1X LPU IV Phono is available in Special ( £24k ), Classic ( £34,200 ) and Sign a ture ( £46,200 ) versions, which differ in the number of chokes, transformers over high class, the material of the windings of transformers and the careful selection and manufacturers of components.

You can also choose to finish the component’s front panel in silver or matte black .


SW1X LPU IV Phono stage Specifications:

  • Three stages of amplification
  • Bulb set: 2 x SJ7, 1 x 6SN7, 2 x 6F6, 1 x 5U4GB, 1 x 5Y3
  • Specially designed SW1X Audio Design signal transformers with Super HiB DC core and silver windings
  • Black Gate VK capacitors in the power supply
  • Non-magnetic niobium resistors AN with a power of 2 W on a bakelite board
  • Super HiB mains transformers with double C-Core core for power supplies
  • Interstage silver foil capacitors
  • AN 2W silver non-magnetic tantalum resistors
  • 2 mains transformers and 5 chokes
  • Active RIAA correction
  • Input impedance: 47 kOhm
  • Output impedance: < 20 ohm
  • Total gain: 46-52dB depending on lamps selected
  • Maximum input voltage: 350 mV
  • Output noise, unweighted (mVrms): <0.5
  • Maximum power consumption (W): 55
  • Dimensions (W x H x D): 440 x 140 x 410 mm
  • Weight: 21.5 kg