SW1X LPU II Phono Pre-Amplifier

SW1X Audio Design™ LPU II

Performance Level 2

Valve Phono Pre-Amplifier

The LPU II is the fuller size & higher gain model of the LPU I.

The sound of LPU II is characterised by a lush yet lively and bold presentation that makes vinyl playback stand out above anything else.

Acoustic instruments and human voices sound completely naturally with accurate dense timbres, lacking of any mechanical signature.

The LPU II MM RIAA Phono pre-amplfier is based on a classic circuit design used to master vinyl recordings and master tapes. Similar to LPU I, it is a two gain stage, active RIAA equalization design. The input stage utilises lush sounding 2 x EF86 valves, loaded by RIAA equalization network and is amplified by the 2 x EC86 single triode tubes on the output stage.

LPU I, LPU 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-Amp range a time-less classic.

SW1X Audio Design™ LPU II 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
Pure Class A, Zero NFB, Single Ended, all Valve Amplification RC (resistive loading/capacitive de-coupling) Circuit Topology
Based on 2 x EF86 Pentodes Input and 2 x EC86 Single Triodes on the Output
Active Series-Resistor-less RIAA Equalization
PIO or Film/Foil de-coupling Capacitors in Inter- and Output Stage
5Y3 Valve Rectified CLC2RC (choke filtered) B+ Power Supply
47K Input Impedance & < 2K Ohm Output Impedance
Total Gain is approx. 50-56 dB depending on the Choice of Valves
Maximum Input Voltage: 350mV