SW1X PRE III

The SW1X PRE III is a pure Class A, zero negative feedback line preamplifier with a signal output transformer-coupled EL84 valve output stage, the more refined and transparent sibling to the PRE II, delivering a near-zero 4 ohm output impedance and the tonal purity, scale, and dynamic authority that only a transformer-coupled power valve output stage can provide. Available in four transformer quality levels from Standard to Signature.

Type and Technology

Line preamplifier with optional phono stage, single-ended Class A vacuum tube with signal output transformer (OPT). OPT-decoupled output stage using EL84 power pentodes in triode connection, driven by 6N6P or 5687 double triode. SW1X custom-wound signal output transformers available in four grades: M6 EI core (Standard), all-copper Super HiB DC core (Special), copper/silver Super HiB DC core (Classic), all-silver Ultra HiB DC core (Signature). 5U4GYB or 5Y3 directly heated valve-rectified CLC2LC choke-filtered B+ power supply. Hybrid point-to-point hardwiring. Dual mono 24-way SW1X stepped attenuators made from the finest materials and selected resistors. Internally wired with SW1X Magnum, Genesis, and Opus conductors. Available with optional PRE III LPX phono stage, EF86-based MM phono with its own 5Y3 choke-filtered supply. Output impedance: 4 ohms.

Sound Character

Transparent, tonally pure, and possessed of the dynamic authority that the combination of power valves and output transformers uniquely provides. The PRE III's output transformer removes the output stage from direct contact with the downstream load, allowing a purer and more controlled coupling to the power amplifier. The 4-ohm output impedance means the PRE III can drive virtually any power amplifier load without compromise. When configured with the Signature silver-wound OPTs, the PRE III represents the finest analog preamplifier in the SW1X lineup below the PRE IV.

Build and Finish

150 x 440 x 400mm at 17kg (22kg with LPX phono). Four OPT quality levels available as variants. Specifications subject to SW1X's ongoing research and development.

Best For

SW1X DAC and LPU Phono owners who want the full SW1X system experience, and those who want the dynamic authority and tonal purity of a transformer-coupled valve preamplifier output stage with near-zero output impedance.

Specifications