SW1x LPU III Balanced Phono Pre-Amplifier

SW1X Audio Design™ LPU III

Balanced EF86 Valve Phono Pre-Amplifier

“The LPU III’s transparency and 3D presentation made me feel like I’d been pulled right into the room where the group performed.” – Michael Fremer

The SW1X LPU III Balanced Phono Preamplifier delivers a listening experience that’s as natural as it is immersive. With an organic sound signature, it brings music to life in a way that feels unforced, smooth, and emotionally engaging. The LPU III’s rich, warm tones, paired with its dynamic clarity and expansive soundstage, ensure every detail is presented with breathtaking authenticity.

Just like with all our Balanced versions, highest Quality Signal Output Transformers further improve transparency & dynamics over LPU I and LPU II. The classic RIAA circuit is made of specially selected materials & components out of production and only available in limited quantities.

LPU ILPU II and LPU III family of Phono Pre-Amplifiers share similar tube input stage- a pair of EF86 pentode tubes. Due to the brilliant sound character of the EF86 those tubes were commonly used in many radios and RTR tape recorders in the early 60s. The idea of their circuit design was borrowed from the input stage of early Reel to Reel (RTR) tape recorders, which were used in the mastering studios and radio stations. Maybe that is one of the reasons as why most recording from the 60s are sounding at their best, much better than from the 70s and 80s? In a way, the EF86 input tube design closes the loop and makes all our LPU Phono Pre-Amplifier range a timeless classic.

The phono preamp’s airy and convincing spatial staging was matched by its delivery of well-saturated, natural instrumental timbres with rhythm’n’pacing and “punch” to spare.

Michael Fremer – Analog Corner

SW1X Audio Design™ LPU III 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
• Classic 2 Gain Stage Pentode Input-RIAA-Triode Output 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 EF86 Pentodes Input and 2 x 6S45P Special Driver Triodes on the Output
• Active Series-Resistor-less RIAA Equalization
• 5U4GB Valve Rectified CLC2RC (choke filtered) B+ Power Supply
• 47K Input Impedance & < 20 Ohm Output Impedance
• Total Gain is approx. 46-52 dB depending on the Choice of Valves
• Maximum Input Voltage: 350mV
• Orient Grain, M6 EI Core, Copper flux banded, mains Transformer & Chokes

Tube Compliment

2 x EF86, 2 xEL84 (Single Ended) 2 x 6S45P /WE 437 (Balanced) 1 x 5U4GB