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Proprius Amp tweaking......

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BAK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BAK Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 2:30am
Higher efficiency speakers do play into the "minimalist" role.
   Any speaker rated above 85 dB will work for this... but the higher the better!
1st > It takes less power to get the same amount of sound... and less power consumed from the AC mains.
2nd > One can use a smaller amplifier, with headroom built in, one that is just powerful enough for your needed listening area.
3rd > A smaller power amplifier will have less active components to muddy the sound and will not generate as much heat.
       ( Graham called them diode junctions, they are in all transistors)
        Active components include valves (or tubes), transistors, and operational amplifier ICs.
4th > A smaller physical size will make for a neater sound system presentation.
         (The Proprius amps can be located behind the speakers to further reduce clutter.)


Edited by BAK - 11 Jan 2016 at 2:33am
Bruce
AT-14SA, Pickering XV-15/625, Technics SL-1600MK2, Reflex M, Lautus, Technics SH-8066, Dynaco ST120a, Eminence Beta 8A in custom cabs;; Using Majestic DAC
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ROMPerformance Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 2:33am
Jon/Bruce, 

I hear what you're saying about the listening space, and i've already visited that idea, unfortunately my two tier office desk with two screens, 5.1 Logitech pc speakers, laptops, paperwork, printer etc..., occupies that bay window space so no go on that one hence why i have to use the 3.0Mtr wall for the large screen and speakers on stands either side. 

I'll have to get creative with a couple of portable fabric office/desk space dividers.     
Francis :0)
Majestic DAC, Proprii, Solo ULDE, Voyager, Libran, Lautus, Spatia,, Cyrus CD XT SE2, Cyrus PSX-R, Sennheiser HD 800 and 540 Ref2, Harbeth SHL5
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ROMPerformance Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 2:44am
Graham,

From what's been posted on this thread so far it doesn't sound like your little amps are going to have any problems clamped to a pair of Harbeth C7ES-3.  

I'm looking forward to the experience.

Many thanks for the circuits diagrams and explanations. 
Francis :0)
Majestic DAC, Proprii, Solo ULDE, Voyager, Libran, Lautus, Spatia,, Cyrus CD XT SE2, Cyrus PSX-R, Sennheiser HD 800 and 540 Ref2, Harbeth SHL5
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveG Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 9:48am
I reckon I will have to check out a pair of Proprius (es???) before I'm too much older. My main system is evolving  into a single source. (if evolving is even the correct term for something that is actually getting simpler & simpler Wink). TT -> Reflex/EXP -> Proprius -> Speakers connected with Cusat/Spatia does have an appeal.

I used to have an some Moth series 30 stereo amps/passive pre bi-amping my Tannoys years ago. They were thoroughly enjoyable and quite capable of upsetting the neighbours. I think they were only 30 watts pc. I wish I'd kept them as a reference if nothing else. They probably went in a skip. I've also used valve amps ranging from 12 -25 watts. Volume was never an issue, though ultimate SQ perhaps was. Since then power seems to have grown & grown with each "upgrade" and I must confess my present amp is a 250w monster packed with audiovile components Embarrassed.

I'm curious. Why does a volume control perform at it's best around the half way mark Bruce? Not doubting what you say at all, just wondering what the explanation is. Indeed I've often heard this asserted before. My own amp rarely gets turned up beyond 5 past 8. The difference between loud enough & too loud is small and needs to be done by hand as the remote doesn't do small enough increments.
Dave

Michell Gorbe + HR PSU -> Cadenza Bronze -> SME V -> Elevator -> Accession -> Proprius -> B&W CM6 s2 | Cusat 50 & Spatia cables ->
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Richardl60 Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 7:43pm
I am not sure whether Graham produces anything but Rothwell produce plug in attenuators that are very effective in providing greater volume range by attenuating the input signal. This my be more prevalent with Some CD players and may are likely to reduce some of the often found CD hardness. Were around £40 a pair when I last bought some some years ago.

Well made and think another good Yorkshire company!

In my experience I agree that the 'best' sound tends to come when preamp volume control is 10.30 to 12.00 o'clock best balance between openness, power, dynamics and clarity. This has been subjective on 4 amps over the years and whilst not fully sure on the science suspect may be related to minimising possible preamp overload in some cases and allowing the power amp to function properly I am sure the more educated may be able to clarify.

Richard


Richard



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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveG Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 7:59pm
Aah, yeah - I used to have some of those attenuators - I wonder if I still do Confused
Dave

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Post Options Post Options   Thanks (0) Thanks(0)   Quote BAK Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2016 at 8:33pm
Make sure any and all attenuators used are completely 360 degrees shielded (encased in metal on all sides with no gaps) or you may get extra noise and a possible radio station.
#1 Any attenuator needs to be matched to the impedance of the input it is connected to at a minimum.
    It would be best to match to the impedance of the preceding stage's output, too.
BUT, matching it to the input of the following stage will be very close to the same frequency response and clarity.

NOTE: The attenuators used for Mic inputs are at a very low impedance, say 100 to 600 ohms and will not work good when connected to a 10k to 100k ohm input. Valve (tube) circuits can be as high as 1 MegOhm or more, but most valve amp inputs are 50k to 250k ohms.

Those impedance specs should be given by the unit manufacturer... many do not state the true output impedance.
 The impedance of a circuit's input and output are an AC impedance and not purely resistive.
      Any coupling capacitors and cable matching caps and coils are included with resistors in the AC impedance specs... a complicated calculation.

For those that cannot turn up the volume above "1" on a "1 to 10" volume scale, use a 20 dB attenuator.
    (For limited to "2" or "3", use a 10 dB.)
This will bring your volume control range close to the middle, "~4 to ~7" (between 10 o'clock and 2 o'clock).
    ( In scientific math, the tilde ~ symbol = approximately)

Guitar players will remember some amps having a volume scale of "1" to "11"Wink. (Making one think they had "1" more volume step above "10" .)

I had a high end 90w per chan amp in the 1980's that had a 20 dB attenuator built in. I always used it to keep my volume range close to the middle. With 97 dB @ 1w/1m sensitive speakers I couldn't turn it up above 1/10 watt before the neighbors complained.
 I can give you more info on the science of the volume control next.


Edited by BAK - 11 Jan 2016 at 8:57pm
Bruce
AT-14SA, Pickering XV-15/625, Technics SL-1600MK2, Reflex M, Lautus, Technics SH-8066, Dynaco ST120a, Eminence Beta 8A in custom cabs;; Using Majestic DAC
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