Proprius mono amplifiers (one pair)

Proprius mono amplifiers (one pair)

"For an output rating of only 25 watts per channel and being so small in stature I couldn't believe how loud and good these little amps sounded. My resident Triangle Titus EZ's are relatively efficient but there was loads of power in reserve and I never felt the amps would run out of steam in my average sized living room. . . The sound is very clean, smooth but detailed and three dimensional." 1

"Having 'downgraded' from some serious valve amplication costing several times the asking price, the GSP combo didn't sound out-of-their-depth at all. No transistor amp (and only a couple of valve amps) has ever matched the sheer musicality and transparency of the sublime Yamamoto but the Majestic/ Proprius were not a million miles behind, sounding unusually sweet and open for a transistor design..." 2

"This is about music; this is real class Ab - not D or T; this is about ease of listening, and an amazingly good amount of audio level despite the low power numbers; all those sudden bursts that many an amp needs hundreds of Watts in reserve to deliver with any meaning, are catered for with comfort here, even when I connected them to my 83dB sensitivity 15ohm LS3/5a speakers. . . This had grunt, with an exceptionally dynamic and energetic soundstage from the deepest lows to the tizzling tops. . . That this 21st Century £1299 all-in package can sound as good as it does is indicative of Slee's compulsion with creating the very best. . . This is real class in a pint pot, and well worth the price." 3


Proprius mono amplifiers (one pair)


Product Info


The Proprius is much more than an audio amplifier - it's a most incredible sounding high fidelity amplifier you've simply got to hear! If you applaud elegantly simple designs that work reliably and sound incredible year after year, then these are the amps for you.

Propius Amp Specifications
- Power output (rms) measured: 26 Watts into 8 Ohms; 45.5 Watts into 4 Ohms (ref 1% THD+N at 1kHz)
- Power bandwidth at rated power into 8 Ohms: 10Hz - 47kHz (-3dB), 20Hz - 25kHz (-1dB)
- Power bandwidth at rated power into 4 Ohms: 12Hz - 40kHz (-3dB)
- Total harmonic distortion and noise at 8 Ohms: 100Hz: 0.043%; 1kHz: 0.047%; 5kHz: 0.061%; 10kHz: 0.085%; 20kHz: 0.125%
- Total harmonic distortion and noise at 4 Ohms: 100Hz: 0.066%; 1kHz: 0.071%; 5kHz: 0.094%; 10kHz: 0.129%; 20kHz: 0.181%
- Signal to noise ratio in dB: "A-weighted": 87dB; 22Hz-22kHz "Q-pk": 80dB
- Bias type: Class Ab; Bias current: 60mA (approx.)
- Input sensitivity for rated output: 575mV rms
- Short circuit protection: Fuse and power supply shut-down (short circuits should be avoided to prevent component stresses)
- Fuse: F2A 5mm x 20mm (glass "quick-blow" fuse rated at 2A)
- Power supply: 48V DC, 120 Watt - self adjusting to AC mains 100V - 240V, 47 - 63 Hz; IEC cord supplied
- Dimensions (approx.): Amp W105 x H55 x D205 mm; Power supply W65 H40 D170 mm

Graham Slee
HiFi System Components Limited
6 Buttercross Drive
Little Houghton, S72 0HS
+44 (0) 1909 568739
+44 (0) 7947 107188
+44 (0) 1226 755328

Footnote 1: Ian Ringstead, "Hifi Pig Magazine", May 07, 2015.
Footnote 2: Geoff Husband, "TNT-Audio", July, 2015.
Footnote 2: Janine Elliot, "Hifi Pig Magazine", May, 2015

Customer Reviews