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Proprius 25W/45W Mono Block Power Amplifier

Proprius 25W/45W Mono Block Power Amplifier


7 Great Reasons To Choose The Proprius

The Sound

The Proprius has all the sonic hallmarks you expect from Graham Slee...

Listening is riveting, involving and fatigue-free. Using two for stereo, imaging is spatially focused and "walk-through" - transcending the speakers, but importantly, the music remains cohesive.

The Proprius is tonally accurate producing a silky and fluid treble with no hint of brightness or grain. Good bass extension and articulation meters out appropriately scaled slam and "grunt", as well as rhythmic satisfaction.

Vibrant dynamics with impeccable timing keep a grip on the performance, with no loss of underlying subtle melodies.

Generously Rated

You may think a 25 watt amplifier is too frail, but the Proprius is anything but!

Each output transistor can handle 25 amp peaks and 200 watts, and at 30MHz their high frequency performance is ten times higher than regular output transistors.

The Proprius outboard power supply is 120 watts to provide unassisted the 2.5 amps its 20 volt peaks demand. Only with impedance dips and when driving 4 Ohms are its reservoir capacitors called on to release stored energy required to ride transient peaks.

Compact Proportions

Finding space for all your hi-fi gear can be tricky, but at just 10.5cm (4.1") x 6cm (2.4") x 20cm (7.9") you'll easily find the space for a pair!

A Power Amp With A Volume Control?

Why not? We gave the Proprius a volume control to give you more flexibility. In a frugal single source system you don't need a line-stage, just a pair of Proprius. In a surround system you might wish to balance the sound levels on each amp. The same if you're bi-amping or tri-amping. What if your preamp doesn't have a balance control? But if you don't need a volume control, just set it to max!

Balanced or Single-Ended Input In One

A single XLR input connector accepts both balanced and single ended feeds.

Connect it to a balanced source and the interconnect length can be considerably longer meaning you can place the Proprius at the speaker, or even screw it to the speaker back with the supplied adaptor plates.

High Bias

Most domestic listening is done at around 1 watt. With medium sensitivity speakers that single watt produces around 80-90dB of sound pressure one metre in front of the speakers. The emotional signature and spatial information in the music is much lower in level - perhaps a tenth of a watt or less.

Unless properly biased into conduction, an amplifier output stage will distort and sound "dry" (Class-B). Give it more bias and the sound is clearer with more body, but give it too much bias (Class-A) and the bandwidth is curtailed often resulting in a "warm" and "syrupy" sound.

High-Bias provides just the right amount, bringing out the emotional signature and spatial information your music craves.

Hot Pluggable

Untypically the Proprius behaves impeccably during power-up and power-down - no loud "thuds" so it doesn't have or need any current stealing output relays.

There are no damaging DC offsets so you can plug and unplug its XLR without fear.

It has intelligent output protection (which incidentally doesn't act prematurely) and because it doesn't have any nasty DC offsets on its output, it allows you to connect and disconnect speakers while it's on.

And because there is no DC on its output it cannot damage your speaker voice coils.