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Proprius/Majestic: Describe the Sound
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discrete badger View Drop Down
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Points: 479 		Post Options Post Options   Thanks (0) Thanks(0)   Quote discrete badger Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 2021 at 7:36am
The Zu speakers are the opposite of inefficient....
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From memory Zu speakers achieve their efficiency via low resistance (4 ohm).

The Proprius is similar to valve amps in that it seems to give it's best with a resistive load.

Perhaps Graham will comment but to my ears low resistance speakers need more watts and whilst the Proprius has more than enough power for my living room it isn't a watt monster.

Bottom line is the loan scheme is the best way to decide if they work for you.
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I agree with you that low impedance speakers draw more current from the amp so more watts. The loading can also be challenging due to phase changes. Having tried my Proprius amps with quite a few speakers including low impedance ones, I think they coped well and the results were very good.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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My Proprius is attached to Focal Aria 936, claimed 92 db,  8 ohms and able to reach 3 ohms and so very efficient. i use a similar design DAC to Majestic. I hardly use my Rotel amp of 1979 or even now my 3OOB single ended ......Proprius provides a balanced between Valveee and transitoreee ........

Two mono amps, 8 inches from Speaker binding post,Smile makes for sublime sound and I listen to Acoustic jazz and Folk and Blues ....  
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Points: 7 		Post Options Post Options   Thanks (0) Thanks(0)   Quote MNdoug Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 2021 at 12:54pm
For what it's worth, my Zu Omens are rated at 12 ohm and 97 dB.  They have gotten along well with every modestly-powered vintage ss integrated I've hooked them to. Also, my listening room is small and I don't crank the volume. So, I'm thinking the Proprius should be a good fit. 
Sansui AU-555A, Zu Audio Omen MK.II, Technics SL-1210GAE w/ Nagaoka MP200, Graham Slee Accession, Black Ice Audio Glass FX Tube DAC_DSD Wifi, Yamaha CD-S700, AudioQuest Niagara 1200
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My PMCs are 8ohm with a low of 7ohms. An easy drive, and the Proprius is glorious. Easy to get to 80dB which really is too much for my room.
Mick.
Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2
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Points: 16298 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 2021 at 5:08pm
Originally posted by Bags Bags wrote:


Perhaps Graham will comment 

Thank you for the invite. Wink

Low impedances draw more current, and current by volts equals watts.

If we take 4 ohms, then the voltage swing available is about 13.5V rms (equates to 45.5 watts).

That causes 3.375 amps to flow, and the power supply voltage is 48 volts. The power drawn from the power supply is 162 watts.

Although the power supply is rated at 125 watts, it manages to do 30% more, which is proven by the maximum power test which gave the 45.5 watt output.

Most amps use underrated power supplies, as might be noticed from lids off images on the internet. Cambridge and IAG designer, Doug Self (he may be retired by now) suggests a transformer rating of 70%, which is the equivalent of our 30% overrating of the 125W PSU.

The R&D I'm doing on the 1970s Design Indulgence has demonstrated even 48% of rated power will provide full output (40WPC) - just that the transformer gets hot on continuous test.

But the arguments about power and speakers fall flat on their faces, when one does the right tests. We generally listen at power levels of one watt or less, and that's loud for an average sized lounge. The dynamics of transients are added on top, and are normally about +14dB, so for one watt, you need 25 watts for the short lived transients.

This is why some amps get away with very small transformers, and rely on the power supply smoothing caps to carry the transients.

However, these days, more listeners tend to be old rockers instead of classical buffs. Therefore, the amp must carry longer peak power, without sagging, and that's the reason for sizing the power supply more realistically.

If it can't carry the longer term peak power, it distorts and the low powered transformer amps are tested on short impulses, which modern analysers can do at the press of a button. The distortion gives the brightness.

Our first two analysers were of the analogue kind which cannot do impulse power testing, and so when we say 45.5 watts, they're continuous watts, as we couldn't measure it any other way.

OK, I now have a state of the art digital analyser, but I still use it continuous mode.

And that must be what they mean by Yorkshire Watts!
That none should be able to buy or sell without a smartphone and the knowledge in how to use apps
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