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Post by amped on Sept 30, 2017 13:58:55 GMT -5
For 2 channel stay away from the Gen 3 and go with the XPA-1s...Unless Emotiva changes the Power Supply for the new offerings or goes to a true balanced dual mono design it is a no brainer. Too much cross talk and too much noise.
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Post by teaman on Sept 30, 2017 14:27:03 GMT -5
For 2 channel stay away from the Gen 3 and go with the XPA-1s...Unless Emotiva changes the Power Supply for the new offerings or goes to a true balanced dual mono design it is a no brainer. Too much cross talk and too much noise. You will really enjoy that Bryston you picked up amped. My two buddies own them and even after twenty three years they sound amazing. |
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Post by Gary Cook on Sept 30, 2017 17:30:07 GMT -5
I would suggest that anyone who is really curious consider buying a Watt Wizard or something similar.It will tell you exactly how much power your system is using (most of the cheap ones won't catch short peaks, but will give you a very accurate average).You'll probably be surprised at how little power you're using most of the time. Completely agree Keith, but if an amplifier manufacturer is claiming, say, low distortion from a new model amplifier then they publish the numbers. Similarly improved cross talk, higher output watts etc etc. I don't think it's unreasonable to expect that, where an amplifier manufacturer claims better efficiency, they publish the numbers. Surely while it's on the test bench running at various power outputs to check the distortion, cross talk etc it's not that big an ask to note the power draw. Typical measuring points, nothing unusual, at idle it draws X watts, at 1 watt it draws Y watts, at 20% of its capacity it draws Z watts etc. It's not like it requires any extra effort or super exclusive expensive equipment to measure it. That would give the potential customers some idea of the relevancy of the 'more efficient" claim. The same applies to reviewers, I know if I was faced with an amplifier claiming an improvement in efficiency I'd want to test it. Just like I would any other claim from an amplifier manufacturer of improved performance from their bright and shiny new model. For sure music is dynamic and the results in any given system/home/user may vary, but that applies to every measurement published. Cheers Gary |
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Post by leonski on Oct 1, 2017 1:36:37 GMT -5
Gary, the General Rule is that Inaudible IS inaudible. Making a measurment even MORE inaudible doesn't buy you much, except perhaps 'bragging rights'.
Also? Some specs are 'bought' at the expense of either audible artifacts or other measurables. The Japanese went thru an 'era' of .0000000x distortion measures which were probably beyond the capabilities of the
measurement systems (inferred or calculated number of some sort?) while having problems due to what were apparently several FeedBack loops and Global FeedBack (from output to input, basically)
A/B amp efficiency is a known quantity. Maybe not to exceed 55% or maybe a tick more. Plug to speaker is the number which most should be concerned with. Due to 'overhead' of simply running things, the efficiency at maybe 5 or 10 watts total will be
Very Low.
Keiths idea to use a meter, of which I have one and may be persuaded to actually USE for this purpose, is a good one. I'm not too concerned, however. My Plasma TV which used a lot of power is gone, replaced by a far more efficient type. My 'D' amp which was mid-80s
plug-to-speaker is gone, too, and replaced by LESS efficient A/B amps with a Linear PS. The 'D' amp? A B&O ASP moduled amp and the efficiency was at Full Tilt. Efficiency drops at lower powers and is essentially Zero at No Output.
I personally don't place much stock in the 'more efficient' claim. You MIGHT gain a few points with the new Switcher, but basically, you ARE Losing a Lot Of Weight which materially effects shipping costs and damage possibilities. Some of the weight loss might be sacrified to
larger heatsinks? But that is an engineering decision.
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Post by Gary Cook on Oct 1, 2017 6:06:29 GMT -5
Gary, the General Rule is that Inaudible IS inaudible. Making a measurment even MORE inaudible doesn't buy you much, except perhaps 'bragging rights'. Also? Some specs are 'bought' at the expense of either audible artifacts or other measurables. The Japanese went thru an 'era' of .0000000x distortion measures which were probably beyond the capabilities of the measurement systems (inferred or calculated number of some sort?) while having problems due to what were apparently several FeedBack loops and Global FeedBack (from output to input, basically) A/B amp efficiency is a known quantity. Maybe not to exceed 55% or maybe a tick more. Plug to speaker is the number which most should be concerned with. Due to 'overhead' of simply running things, the efficiency at maybe 5 or 10 watts total will be Very Low. I'm not sure what efficiency has got to do with audible or inaudible. But when a car manufacturer claims better efficiency from its new model everyone expects them to quote what the efficiency is. It's not just accepted, it's expected or maybe actually demanded, that they show us the numbers that support that claim. If a big change is made like moving from a toroidal based linear power supply to a switch mode power supply and is justified by an efficiency claim ithen it's not reasonable to expect that it won't be questioned. A Class AB amp with a toroidal based linear power supply may well be a know quantity but SMPS Class H power supplies coupled with Class AB amps are not so well known. In Australia we have a saying that goes "put up or shut up" which in this case means if you want to claim better efficiency then you'd better be able to back it up. I agree some specs are "bought", so why should we expect or accept that the claim for better efficiency doesn't compromise something else. Or that something else doesn't compromise the efficiency. Cheers Gary |
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Post by leonski on Oct 1, 2017 15:06:59 GMT -5
Gary, I think I fundamentally agree. But we are talking 3 things here. PS efficiency IS greater for a switcher. Cost? Greater complexity, maybe lower (somewhat) reliability and questions about dynamic power OutPut stage efficiency IS what it IS. I don't see that being changed by a PS change My conclusion? Total Package efficiency MAY be slightly better. But don't invest in the new stuff yet. The marginal help in efficiency has a finite payback time which may be years or Decades. Full Power efficiency is something NOBODY but a bench tester ever sees. All amps efficiency is ZERO at No Output. sound.whsites.net/efficiency.htmElliot Sound Products has an EXCELLENT article on this very issue. For Your Consideration:: Relative to the Auto Example? Most look at Fuel Economy as a measure of efficiency. Can't arugue much with that. But FEW are concerned with Cost Of Ownership which includes stuff like Tires, Insurance, Maintainance and other reliability costs. My S-2000 even moderately driven went thru a set of REAR tires 2x faster than the fronts. Differential sizing meant No front/rear rotation! As for amp 'specsmanship'? Lets say you have a mono amp which on the bench produces 300 watts. 1% clipping is NEVER less than 350 watts. So far so good? ALL of 'em off the line do this. So? You rate it for 250 watts and get an automatic 1.5db dynamic headroom. Boom! Another great spec. CALCULATION: (P@1/%/ P@rating)10log= db The Kill-A-Watt meter is a terrific Cheap Investment. www.amazon.com/s/?ie=UTF8&keywords=kill-a-watt+meter&tag=googhydr-20&index=aps&hvadid=153731920454&hvpos=1t1&hvnetw=g&hvrand=3814303686744868817&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031305&hvtargid=kwd-419677973&ref=pd_sl_1bgov6apqq_eThe original meter is now 20$ and should be in everyones 'kit'. Doesnt' capture 'instant' peaks, |
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Post by pknaz on Oct 1, 2017 15:35:08 GMT -5
See my post on the latest thread on this topic. If one is concerned about the cost of operating amplifiers, it seems to me they wouldn't be buying big iron (in any form) to power low sensitivity speakers, they'd be buying high sensitivity speakers (>98db/w/m) and powering them with a little 10-20 watt amplifier (which would break your ear drums).
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Post by leonski on Oct 1, 2017 17:22:31 GMT -5
I get it and agree. High sensitivity speakers ARE a way to end up with lower powered amps which Still do it all. But you must find such speakers you like. And can afford.
You might get caught up in 'the laws of physics' too, where certain tradeoffs might end up with some large speakers of higher sensitivity.
One big revolution of HiFi occurred 50+ years ago with the 'advent' (no pun intended) of 'Small Box' speakers and relatively inexpensive SS Watts.
By small box speakers, I mean stuff like the AR 3a series which was quite the speaker but much lower sensitivity than the Big Box folks were used to.
I see reference to maybe 90db and 4 ohms for that model, which is 1/10th that of a 100db speaker. That's a LOT of amp!
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Post by pknaz on Oct 1, 2017 20:43:57 GMT -5
Don't get me wrong, I have XPA-1 Gen 1's (Way over kill) powering 4ohm 89db/w/m speakers (that are as big as I am), and I almost never even see a single LED light up when listening to music. Only once in a blue moon do I see those purdy lights blinking, and even then, its usually only the first one or two  My comments were more targeted at the conversation regarding potential savings from an electric bill by moving to an SMPS power supply versus a linear power supply in the Gen2 vs. Gen3 amps. I personally think that design decision had more to do with shipping weight of the amps than any marketing, real, or perceived changes to the performance of the amp. I'm not sure who mentioned it already, but I tend to agree. Upgrading from a linear power supply amp to an SMPS to potentially ROI the reduced electric savings is a bit like buying a new car to save money on gas mileage. I'ts almost impossible to actually ROI. No problem what-so-ever, though, with anyone who just wants to try out new things, that's why we're all here! |
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Post by leonski on Oct 1, 2017 21:37:31 GMT -5
PK, I will just call your experience the 'middle' of the road. Barely get the massive power of the XPA-1 to even blink, let alone break a sweat. Pretty much what I'd expect from 89db sensitive speakers. Your Job? Get a Kill-A-Watt meter and report back with idle power. This is ALL HEAT with no music playing and will give some idea of the Iron (transformer) and copper losses as well as the state of bias. Maybe even play a 1khz Test Tone at the lowest level which makes the first meter light flicker. No more than 30 seconds for this test, please. Now that I think about it, Stereo / HiFi and HT is NOT a hobby / avocation where people care the LEAST about ROI. Somebody living in Florida will have a pair of the XS-300 amps from Pass Labs which is a 4 piece set of 2x PS and 2x Output sections. Total weight for the works? Nearly 600lb. And don't forget that EACH amp IDLES at 1000 watts, but doesn't increase as demand increases, being pure Class 'A'. I heard these at a show and the room was Sauna Hot since the amps simply OverWhelmed the AirCon. Not a chance. They shut down the Demo to give the place a chance to cool and the people to BREATH. www.tonepublications.com/review/pass-labs-xs-300-monoblock-amplifiers/ |
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Post by pknaz on Oct 1, 2017 22:51:40 GMT -5
No need, they never idle. They're setup on 12v triggers, and if content isn't playing (through the XMC) they shut off. That's my idle efficiency! And I agree, I don't care one lick about how much power they draw, same reason I have a plasma instead of an LCD  |
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