Proprius is great!

sunday wrote: I've got to say that this combo is, by far, the most compact and best sounding system I've heard at any price point. the build quality is very good, not fancy but very well made, very easy to use, easy to carry.

You echo my thoughts about the Proprius completely. Just from inspecting the Proprius monoblocks, you can see just how well built they are. (All of Graham's products have attention to detail) Then comes the joy of listening to them... An exquisitely neutral and articulate performance they give to high-fidelity speakers in an optimised listening space. If I was wealthy and had a dedicated listening room, I would not be selling my Proprius. Well, if it's any consolation to Graham, I would never buy speaker amplifiers from another manufacturer.

Because they are so well designed, Graham can also forecast the lifespan of his electronic circuits based on electrical degradation of PCB components (after which time the circuits may deviate from specification). But even after this time (typically 10 years for many of them, I think), remedial recapping would be able to restore them.


Edited by Ash - 19 May 2014 at 11:22pm

If the Proprius were the regular design everybody else uses - just like an op-amp - differential input stage used single ended; voltage amp; output stage, then it would be a 35 watt amp, and absolutely easy to design... but it would not have pleased me! I was building those and selling them in kit form in 1979 - I designed a studio amp in 1992 just like those, and it was used in broadcast studios all over the UK.

The Proprius had to be different to sound different. One manufacturer did similar a long-long time ago, but without the high frequency power transistors available today. I sacrificed 10 watts of output to get that sound. The Proprius is unique.

Aussie Mick wrote: Graham, after having the Proprius in my system via the Australian loaner program something is troubling me. When I look at the spec sheet I see that the signal to noise ratio doesn't look as good as many "high end" amps, but it is one of the quietest I've heard at home. In this instance the spec sheet seems to be all but irrelevant. Am I missing something? I used my Reflex M directly into the amps. Loved it. I have a Majestic on the way, to be followed by Proprius when I can afford it. Cheers, Mick.

Mick, maybe it's because we use professional measurements and not hi-fi ones? Having worked in (he says trying not to sound like he's labouring the point) broadcast audio, I find it hard to change to hi-fi measurements, and that may be why my spec says "some noise", but the amp is found "not to do noise"?

It is quite easy for a test chap to pull in a filter at 1kHz and state the noise at that spot frequency, which is bound to be a low figure. The bandwidth of 20kHz is what should be measured, and to convert a spot frequency to wideband requires it multiplying by the square root of the bandwidth. For 20kHz that is approx. 141 times, which is 43dB in decibel terms. I guess I could take the S/N and make it look 43dB better?