SW1X LPU IV Phono Pre-Amplifier

SW1X Audio Design™ LPU IV

Performance Level 4

6F6 Valve Phono Pre-Amplifier

In addition to Signal Output Transfomer (OPT) de-coupled Balanced design as employed in the LPU III, the circuit design of the LPU IV Phono is based upon larger octal base valves.

Instead of 2 gain stages of the LPU I, II and III, LPU IV Phono is a 3 gain stage design. The input stage of the LPU IV employs the 6SJ7- the octal version of the superb sounding EF86.

The interstage/driver is based on the musical and well known 6SN7 double triode. The output stage is now based on the 6F6 (predecessor to 6V6 as in DAC IV and PRE IV) power valves.

This makes the LPU IV a larger & bolder sounding Phono relative to the already vivid and bold sounding LPU III.

Just like with all our Balanced versions, highest Quality Signal OPTs further improve transparency & dynamics.

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

SW1X Audio Design™ LPU IV Phono Features:

Specially Selected and Harmonically Matched Component & Material Quality
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 Design™ Custom 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, 1 x 5U4GB, 1 x 5Y3

Reviews

Optional Extras:

Fully Hardwired Tube Output Stage on Panzelholz or Bakelite Board
Fine Silver wiring on the Input, Bakelite Board and Output
SW1X Audio Design™ Custom 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

LPU IV Classic

LPU IV Special

Note: Due to SW1X Audio Design’s ongoing research and development process, specifications are subject to change without notice.

Specifications

Dimensions: Height (mm) 140 x Width (mm) 440 x Depth (mm) 410

Weight (kg): 21.5

Max Power Consumption (W): 55

Output Noise, Unweighted (mVrms): < 0.5

Output Impedance (Ohms): <20

Tube Compliment: 2 x SJ7, 1 x 6SN7, 2 x 6F6, 1 x 5U4GB, 1 x 5Y3

Front panel options: Silver or matte Black

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.

LPU IV Phono Pre Amplifier Tube Valve Amplification

SW1X LPU IV

6v6 Phono Pre-Amplifier
Performance Level 4

LPU IV Phono Pre Amplifier Valve Amplification

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 Design™ Custom 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

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 Design™ all Copper wound Super HiB DC Core OPTs
Classic : SW1X Audio Design™ Copper/Silver Windings, Super HiB DC Core OPTs
Signature : SW1X Audio Design™ Silver/Silver Windings, Super HiB DC Core OPTs

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 Design™ all Copper wound Super HiB DC Core OPTs
Classic : SW1X Audio Design™ Copper/Silver Windings, Super HiB DC Core OPTs
Signature : SW1X Audio Design™ Silver/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 Design™ Custom 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

Optional Extras:

Fully Hardwired Tube Output Stage on Panzelholz or Bakelite Board
Fine Silver wiring on the Input, Bakelite Board and Output
SW1X Audio Design™ Custom 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

Note: Due to SW1X Audio Design’s ongoing research and development process, specifications are subject to change without notice

Specifications

Dimensions: Height (mm) 140 x Width (mm) 440 x Depth (mm) 410
Weight (kg): 21.5
Max Power Consumption (W): 55
Output Noise, Unweighted (mVrms): < 0.5
Output Impedance (Ohms): <20