SW1X LPU IV

6V6 Phono Pre-Amplifier

Performance Level 4

Building upon the exceptional design of the LPU III, the LPU IV takes performance to the next level with a Signal Output Transformer (OPT) de-coupled balanced architecture and an upgraded circuit featuring larger octal base valves

Unlike its predecessors—the LPU I, II, and III—which feature 2-gain stages, the LPU IV boasts a refined 3-gain stage design. At the input stage, it employs the 6SJ7, an octal equivalent of the highly regarded EF86, known for its superb sonic clarity.

The interstage/driver section is driven by the musical and widely respected 6SN7 double triode, ensuring rich tonal character and dynamic performance. For the output stage, the LPU IV features the powerful 6V6 valve—which is also featured in our Performance Level 4 DAC IV and PRE IV—delivering enhanced power and depth.

With upgraded circuit design, LPU IV offers an even larger and more commanding sonic presence, making it an essential partner to your turntable.

• SW1X Performance Level 4 circuit design and components
• MM Phono Pre-amplifier is suitable for all moving magnet (MM) or moving coil (MC) in combination with a matching SUT
• 3 Gain Stage Pentode Input-RIAA-Double Triode Intestage-Triode Connected  Output Stage Design
• Signal Output Transformer De-coupled, Zero NFB, Triode Valve Output Stage in Pure Class A, (inductive loading & de-coupling) Circuit Topology
• SW1X Audio DesignCustom Designed Signal Output Transformers
• Based on 2 x 6SJ7 Pentodes Input, 1 x 6SN7 Double Triode and 2 x 6F6 Triode Connected Pentodes on Output
• Active Series-Resistor-less RIAA Equalization for maximum dynamics
• 5U4GB Valve Rectified C2LC2LRC (choke filtered) B+ Power Supply
• 47K Input Impedance & < 200 Ohm Output Impedance
• Total Gain is approx. 46-52 dB depending on the Choice of Valves
• Maximum Input Voltage: 300mV
• 2 x Mains Transformers & up to 5 Chokes

Tube Compliment

2 x SJ7

1  x 6SN7

2 x 6F6

1x 5U4GB

1 x 5Y3

Versions

The Special, Classic and Signature versions push limits with more chokes, higher grade transformers and even more matched and higher specified components & materials.

• Standard : SW1X Audio Design all Copper wound, orient grain M6 EI Core OPTs
• Special :  SW1X Audio Designall Copper wound Super HiB DC Core OPTs
• Classic : SW1X Audio DesignCopper/Silver Windings, Super HiB DC Core OPTs
• Signature : SW1X Audio DesignSilver/Silver Windings, Super HiB DC Core OPTs

Optional Extras:

• Fully Hardwired Tube Output Stage on Panzelholz or Bakelite Board
• Fine Silver wiring on the Input, Bakelite Board and Output
• SW1X Audio DesignCustom Designed & Fully or Partly Silver wound Super HiB DC core Signal Output Transformers
• Super HiB double C-Core mains transformers for the DHT/DHD power supplies
• Silver Foil capacitors Inter-stage Signal de-coupling Capacitors