Ypsilon PST 100 Mk II Preamplifier


The PST – 100 is most certainly an impressive addition to YPSILON’s 100 series. It approaches the concept of pre amplification in a different way, which the purists describe as the optimal topology: At its core are the in house hand-wound transformers used for attenuation. In addition its valve state circuit combined with exquisite materials produce the finest and most natural sound that any pre amp could ever achieve. 

Conventional wisdom suggests that the most critical part of a preamplifier is the active circuit design. Ypsilon, however, believes that the means of signal attenuation (the volume control) is the most critical to the overall sound of a preamplifier. Most designers use resistor attenuators for volume control. We have used resistor attenuators with high quality resistors (Vishay, etc.), in the past, felt unsatisfied from the character they induced in the signal. We developed a very special transformer as the means of attenuation, using special winding techniques and highest quality wires and cores. Its performance suppassed that of the best resistor attenuators. In a transformer the magnetic circuit can be ultra linear when the very best core materials are used. The sound of such materials is much more musical and detailed compared with the best resistors. A transformer attenuator with 31 taps is used in the PST100 mk2 providing a total attenuation of 54db in its lowest tap. 

The active gain stage is a no – feedback single-ended., Siemens C3m triode, which is transformer coupled. The power supply uses valve rectification (using the 6CA4) and choke filter. Wiring is point to point with custom made pure silver wire. The transformer attenuator is placed after the valve stage, preserving the purity and micro details of the signal. The gain is 16db. Output impedance is 150 Ω max.

A passive version of the PST-100 Mk 2, the PST 100 TA is also available without the valve stage for systems that don’t require additional gain. This version is equipped with the transformer attenuators and is called PST 100 TA. Please note that it is fully upgradeable to the full version at any time by returning to factory

The PST 100 Mk2 is the pinnacle in preamplification. It is a must have component for building a “no holds” system. It is available in the standard and silver edition, which encompasses transformers with high purity silver wiring.


Bandwidth9Hz -100kHz -3dB
Output Impedance150 Ohm
Input Impedance50 kOhm
GainX7 (16.9db) In active mode
Input TubeSiemens C3m (x2)
Rectifier Tube6CA4 / EZ81 (x1)
Power Consumption100 VA maximum
Dimensions400mm (W) x 180mm (H) x 410mm (D)

Other Resources

The PST-100 sounded about as close to the source as can be imagined. All sources, analog or digital, were steps more transparent, three-dimensional, and closer to sounding “live”—or at least closer to the source going directly to the amplifier—than I’ve otherwise heard in my listening room.

…. Ypsilon’s PST-100 Mk. II is a full-function preamplifier that can drive most amplifiers in its passive mode, but can add a remarkably transparent, tube-based active stage when needed. It is beautifully and simply built using custom-designed transformers wound in-house, point-to-point wiring with custom-drawn silver wire, and hand-selected tubes designed for long, quiet, trouble-free use.

Michael Fremer, Stereophile, July 2011

Disappearing Act

I mean it. I don’t know if things “disappear” any more if you use the Ypsilon PST 100 with the Ypsilon SET 100s and the Ypsilon CDT 100/DAC 100 transport/DAC (reviewed by Jack Roberts), but the effect was unmistakable. Performer separation was absolutely phenomenal, and mine was pretty good to begin with. Each performer was in a distinct space, yet the music emanated naturally from that space to every corner of the room. I have listened to several components that accomplish excellent separation (the excellent Pass XP-20, the YG Acoustics Kipod speakers and a few high-end monitors), but the Ypsilon PST 100 does this more naturally than anything I’ve encountered.

Ed Momkus, DAGOGO, September 2009