PST-100 MKII

About the PST-100 MKII

The Ypsilon PST-100 MKII is a premium tube preamplifier designed for audiophiles seeking the highest transparency and sonic purity. It uses two Siemens C3m triode tubes in a no-feedback single-ended active gain stage, transformer-coupled, with a gain of 16.9 dB (x7). The volume control is a custom-designed transformer attenuator with 31 taps, providing ultra-linear magnetic circuit attenuation superior to resistor-based controls, preserving musical detail and purity. The preamp offers switchable passive and active modes: passive mode routes the signal directly through the transformer attenuator with no gain, ideal for sources with low output impedance; active mode engages the tube gain stage for additional amplification. It has six inputs (five unbalanced RCA and one unbalanced XLR) and outputs (one unbalanced RCA, one unbalanced XLR, and a buffered Tape Out RCA). The power supply uses valve rectification with a 6CA4 tube and choke filter. Wiring is point-to-point with custom pure silver wire. The unit weighs 55 lbs and measures approximately 15.6" W x 7" H x 16" D. The PST-100 MKII is highly regarded for its minimalistic design that adds no coloration or noise, delivering a 'straight wire with gain' sound. It lacks balance or mono controls to maximize transparency. The preamplifier is handmade with custom transformers wound in-house and hand-selected tubes for long, quiet operation. It requires a long break-in period for optimal performance and is