The Graham Slee Proprius Monobloc power amplifier delivers 25 watts into 8 Ohms (RMS) and 45 watts into 4 Ohms.
It's a mono-block amp so two are required for stereo. We made it this way for a variety of reasons — one of which allows them to be used remotely at, or fixed to, the loudspeakers for powered monitor performance from your favourite passive speakers — see speaker mount tab. The great thing about mono-blocks is they give you true dual-mono amplification for improved stereo separation.
They're perfect for use with high sensitivity speakers where quality comes before quantity. However, they're not short on quantity and sound louder than their 25 watt rating would suggest, even using speakers as low as 83dB sensitivity — including the Stirling Broadcast/BBC 11 Ohm LS3/5A.
The balanced XLR input works just as well single ended with shorter interconnects so using them side by side like a normal amp isn't a problem — you can find sutable interconnects in our Cables & DIY section.
For remote or speaker mounted placement requiring long cable runs, you'll need a source with balanced outs and our balanced audio cables.
Unusually for a power amp, the Proprius is equiped with its own volume control meaning it can be used direct from a fixed output source. When using it with a control preamp the volume control is put "out of circuit" by parking it at full rotation.
The input is based on the balanced topology by David Birt of the BBC, modified to "all-inverting" making it free of common mode distortion. Absolute phase is accomplished by "phase swapping".
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
Size (approx.): Amp W105 x H55 x D205 mm; Power supply W65 H40 D170 mm
Providing your item is in stock, the order is usually dispatched within 24 hours. Please remember that postage and packing is completely free for orders over £50*. Out of stock items will be dispatched as soon as they become available, out of stock items can take between 4 to 21 days for dispatch.
Deliveries usually take 1-3 working days. The majority of orders are sent via our couriers'; Interlink Express on a next-day-delivery service. Smaller, low value or light-weight items are normally posted using Royal Mail Recorded or Royal Mail Special Delivery.
Once your product has been dispatched, you will be notified via email and sent a unique consignment number, you can use this number at http://www.interlinkexpress.com to check the status of your delivery. If you have provided a mobile telephone number, Interlink's Predict service will notify you by text (and email) of a one-hour delivery window. If the window they suggest is inconvenient, you can change the date of delivery to a later one via text or email.
*We ship free of charge to mainland UK addresses, excluding the Scottish Highlands or 'Out-Of-Reach' Scottish locations. Please consult the post-codes below to see if your location falls within this category. If you are still unsure, please contact us on 01432 354921. We also ship to Northern Ireland, Channel Islands, Scilly Isles, Scottish Isles and Scottish Highlands, however delivery to these locations will incur a charge and can only be sent via a 2-day service.
|Shipping Costs||Mainland UK (Next-Day)||Offshore/Out-of-reach (2-day)Northern Ireland, Channel Islands, Isle of Man, Scottish Islands, Scilly Islands||Republic of Ireland (2-day)|
|Under £50 Orders
|Over £50 Orders
|Saturday by 12 Delivery
Post codes exempt from the free delivery service include:
Scottish Highlands Post Codes: AB30-38, AB41-42, AB44-56, FK17-99, G83, IV1-28, IV30-39, IV52-54, IV63, KW1-14, PA21-33, PA34-40, PH15-26, PH31-41, PH49-50
Islands Post Codes: HS1-9, IV40-51, IV55-56, KA27-28, KW15-17, PA20, PA41-49, PA60-78, PH42-44, ZE1-3
Northern Ireland: All BT postcodes
Channel Islands Post Codes: JE, GY
Scilly Isles Post Codes: TR21, TR22, TR23, TR24, TR25