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Four Proprius connection?

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    Posted: 04 Feb 2016 at 10:07pm
Just received a pair of Proprius amps from the loan programme. Thanks for sorting it so quickly Jon. So far very pleased with what I have heard and certainly no lack of power.

I have the amps connected to a L*nn LP12 deck, Quad 24P valve phono preamp and pair of Totem Tribe 3 speakers.

I have got the speakers bi-wired to the amps with one amp to each speaker. I am interested in having four Proprius amps so I can bi-amp to the speakers. Has anyone tried this? Any thoughts? 

My main question though is, how do I connect the four amps to my pre-amp which has only one pair of output connections.

Cheers, Bob
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 04 Feb 2016 at 10:16pm
Answer: Call John C on 01909 568739. Tell him what you're wanting to do and he can make you the right cables.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jul 2016 at 8:50pm
Graham, I am thinking about possibly buying another pair of Proprius in order to "bi-amp" my sensitive Mark Audio 12 drivers. The Alpair 12P and 12PW have slightly different sensitivity so a volume dial for each would allow me to match them without needing to add any passive crossover components at the drivers themselves. Trial and error with varying resistor values could be pretty tedious. Also, one Proprius per driver would allow me to keep the Proprius dials turned down further for each as less current required. I have found that the 12 drivers can convey low level background hiss to my ears at my listening position if the Proprius dials are above the 10 o'clock position. The hiss is inaudible when music is playing and I only hear it when there is no music playing because my room is really quiet and the drivers are maybe 1m or so from my ears and because they have high sensitivity and quite a large radiating surface. This is why I don't turn the dials "out of circuit" as the hiss becomes more audible the further clockwise the dial is turned. At 9 o'clock position on the Proprius, the drivers are basically "dead quiet" like what I can get from my AKG K1000 at the 3 o'clock position. I know that a single Proprius has more than enough power to drive multiple MA drivers per channel but in theory is there any other benefit of using one amp per driver??

Connection to a second pair of Proprius would be easy as my Majestic unbalanced analogue output is unused and is variable on mine too so is essentially equivalent to what the balanced output is giving my other Proprius pair through single-ended interconnects.


Edited by Ash - 21 Jul 2016 at 8:58pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jul 2016 at 2:47am
You can hear hiss? Wow, those speakers must be sensitive - do they really need an amp? Wink

I would ask Jon Berg if you can borrow the loan pair plus necessary cables and give it a try.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jul 2016 at 11:39am
My ears are very attentive and my room is small and quiet and the speaker cones are more or less on-axis with my ears. The audibility of the hiss is dependent on the position of the monoblock dials only so I turn them about 9-10 o'clock then turn the Majestic dial further up to compensate (still more than enough power available). I use the equipment within its limits; no biggie. The microdynamic resolution of the 12P full-range driver is incredible; reveals even more than the HD800's large diaphragms, in my opinion. The HD800 microdynamic resolution is a bit better than that of my K1000, I think, due to the larger driver size, even though K1000 is more spatial and three-dimensional.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jul 2016 at 3:28pm
I'm running my Proprius full up and sat 15" away from the right hand speaker. I have vinyl switched in right now and if I place my ear about 6" in front of the LS35A on axis I can just make out the hiss. The volume on the Majestic is not very high because I don't want loud today. If I switch to digital I can't hear any hiss. It could be my age??
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jul 2016 at 5:02pm
Not sure.The hiss I'm describing isn't obnoxiously loud, even with Proprius dials turned up quite a way. My ears can just pick up subtle hiss when on-axis. Maybe my power supply was having a bad day a few days ago. The frequency of the hiss is mixed, I guess, but not particularly high pitched. Maybe I'm just being picky as I doubt your hearing is particularly worse than mine despite our difference in age. You're an attentive listener too. Maybe it's due to low driver impedance combined with high driver sensitivity. Want me to link you to the spec datasheets for the 12P and 12PW?

Edited by Ash - 22 Jul 2016 at 5:32pm
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