Stereocheck Reviews:

SW1X LPU IV: Powerful Tube phono amplifier

SW1X Audio Design has launched the SW1X LPU IV phono amplifier. The LPU IV is designed for MM cartridges and MC cartridges with a high output voltage. In addition to the fully balanced output...

SW1X LPU IV
SW1X LPU IV

SW1X Audio Design has launched the SW1X LPU IV phono amplifier. The LPU IV is designed for MM cartridges and MC cartridges with a high output voltage. In addition to the fully balanced output transformer used in the LPU III, the LPU IV Phono circuit is based on more powerful eight-pin tubes. Instead of the two gain stages used in the LPU I, II and III phono amplifiers, the LPU IV Phono has three gain stages.

SW1X LPU IV

The input stage of the SW1X LPU IV Phono is based on two 6SJ7 tubes, an 8-pin version of the EF86 pentode. The intermediate stage is equipped with the popular 6SN7 double triode and the output stage is driven by a pair of powerful 6F6 tubes.

In addition to the basic version, the SW1X LPU IV is available in Special, Classic and Signature versions. The difference lies in the number of inductors and transformers, components of a higher class, the material of the windings of transformers and the careful selection of the manufacturers of the components used.

SW1X LPU IV: technical specifications

  • Three stages of reinforcement
  • Tubes installed: 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 Watts on a Bakelite board
  • Super HiB mains transformers with double C-Core core for power supplies
  • Intermediate silver foil capacitors
  • AN 2W silver non-magnetic tantalum resistors
  • Two mains transformers and five inductors
  • Active RIAA correction
  • Input impedance: 47 kOhm
  • Output impedance: less than 20 ohms
  • Total gain: 46 to 52 dB depending on the tubes selected
  • Maximum input voltage: 350 mV
  • Output noise (unweighted): less than 0.5 mVrms
  • Maximum power consumption: 55 Watts
  • Dimensions (W x H x D): 440 x 140 x 410 millimeters
  • Weight: 21.5 kilograms