Sugden Masterclass LA-4 Class A Line Preamplifier
Sugden Masterclass LA-4 – Class A Line Preamplifier The Sugden Masterclass LA-4 is a high-quality active line preamplifier designed for refined, fully analogue stereo systems. Combining a sophisticated Class A output stage with relay-controlled input and output switching, it provides precise system control while preserving the tonal character, dynamic expression and natural flow of the source material. Overview The LA-4 has been developed as the natural control centre for Sugden Masterclass and Sapphire power amplifiers, including the SPA-4 and MPA-4. Its high-gain architecture provides confident control over a connected power amplifier, while carefully selected transistors and capacitors support clean signal preservation throughout the circuit. Each gain stage is powered by a current-shunt differential power supply. This approach is designed to support rapid transient response and maintain composure during demanding musical passages. Gold-plated circuit boards and relay switching further reflect Sugden’s focus on signal integrity and long-term reliability. Key Benefits Natural system control: the active Class A output stage is designed to preserve tonal balance and low-level detail. Flexible analogue connectivity: line-level, tape, balanced and bypass inputs accommodate a wide range of source and system configurations. Balanced integration: balanced input and output connections suit premium pre/power systems. Convenient operation: motorised remote volume control allows precise adjustment from the listening position. Handcrafted construction: Masterclass components are assembled in Sugden’s Yorkshire factory. Key Features Active Class A line preamplifier Four line-level inputs One tape input One balanced input One bypass input Two line-level outputs One fixed tape output One balanced output Relay switching for inputs and outputs Motorised RC5-compatible remote volume control Tape output defeat function Gold-plated circuit boards Ideal For The Sugden Masterclass LA-4 is intended for serious two-channel systems using a separate power amplifier. It is particularly well suited to owners of the Sugden SPA-4 or MPA-4, as well as listeners who want a premium analogue preamplifier without digital processing, streaming or unnecessary system complexity. Its bypass input also makes it relevant for systems where a dedicated stereo setup shares power amplification with another source or control component. Specifications Product type Active Class A line preamplifier Inputs 4 × line level, 1 × tape, 1 × balanced, 1 × bypass Outputs 2 × line level, 1 × fixed tape, 1 × balanced Input sensitivity 100 mV for 1 V output Maximum output 10 V Frequency response 15 Hz–30 kHz, ±0.1 dB Bandwidth 6 Hz–300 kHz Signal-to-noise ratio Greater than 90 dB Distortion Less than 0.006% at 1 kHz, 1 V output Dimensions (H × W × D) 75 × 430 × 350 mm Weight 7 kg Remote control Motorised volume, RC5 compatible Manufacture Handmade in Yorkshire, England Why We Selected This Product At ExclusivIT, we appreciate preamplifiers that focus on the essential task of managing an analogue system without imposing unnecessary complexity. The LA-4 offers the connectivity required by a serious stereo setup while maintaining a disciplined, carefully engineered signal path. Its combination of Class A operation, balanced connectivity, bypass input and substantial output capability makes it a particularly coherent partner for Sugden’s Masterclass power amplifiers. For listeners building a long-term pre/power system around musical naturalness and understated British engineering, the LA-4 deserves close consideration.