KeithL
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Post by KeithL on Oct 11, 2017 9:02:54 GMT -5
I'll make that calculation very simple for you. Other than the sound and light that escapes out of your windows, and through the walls, ALL of the energy used ends up as heat one way or the other. The only difference is what route it takes to end up there, and how many stops it makes along the way. Next up, I will present my "efficiency calculator"...where you can model the efficiency of each component in your system and determine an overall level. Prepare to be disappointed in what energy wasters we all are! Mark Thanks Mark, please include the energy usage Coefficient for my RPR-1’s or VTA - ST-120 tube amps. Heat used is Not a loss! 😋 heat required during our deep freeze here in Louisiana,,,,,,,, |
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KeithL
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Post by KeithL on Oct 11, 2017 9:16:10 GMT -5
I sort of thought I listed the reasons.... but.... here they are: 1) There are LOTS of measurements we don't provide. This number is among the ones we don't normally measure or post because not that many people seem to care. (And, no, it isn't measured by our standard AP test set, so it's a little more effort than "checking that box".) 2) The idle power consumption on most of our amps (and most others) varies as they warm up... so it would be a range rather than a single number. 3) For the people who are interested on the size circuit they need, or whether they can run two big amps on one circuit, this simply isn't going to provide useful information. For one thing, the idle power is a lot lower that the amount of power they'll draw when playing loudly. For another, the amount of power an amp draws when playing loudly depends TO A MAJOR DEGREE on what type of music you're playing. For example, the average power level on typical music is between 1/10 and 1/20 of the peak level. However, if you're playing pipe organ music, WITHOUT a separate subwoofer, it might be as high as 1/2. 4) If you're willing to ignore that variation, or you've actually figured out your REAL AVERAGE POWER REQUIREMENT, then use this number: At full output, into an 8 Ohm load, a typical Class A/B amplifier is going to be between 60% and 70% efficient (Expect that to drop to around 50% for a 4 Ohm speaker.) My amps have been measured at 2x 8 ohm loads set to 43V effective and putting out 2 x 231 watts while pulling 512 watts from the plug. This translates to 90% efficiency. To me they did sound better than the Sherbourn 7-350. Black magic?  Where is the problem doing and publishing measurements regarding efficiency? Are the numbers so bad?  |
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KeithL
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Post by KeithL on Oct 11, 2017 9:28:02 GMT -5
Incidentally, if anyone here really is running off the grid..... Then the clear and obvious choice is going to be a Class D amp (which includes the "Class T" ones from TriPath). The TA2024 chip-set can deliver about 5 watts/channel (x2) with reasonably low distortion from a set of alkaline AA batteries.... And can deliver close to 10 watts/channel (x2) when run from a more serious power supply. It draws very little idle current, is very efficient, and can actually play music (quietly) for eight or ten hours on a set of AA alkaline batteries. (or for a VERY long time on a bigger 12V battery) Oh, yes, and this one costs less than $15. www.parts-express.com/t-amp-tripath-ta2024-2-x-15w-audio-digital-amplifier-board--320-600If you were wondering; "Class T" amps are simply a Class D variant; extra credit if you can tell us where the name "Tripath" came from.  |
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Post by garbulky on Oct 11, 2017 9:49:01 GMT -5
We've seen a lot of discussion about power efficiencies and it looks like we are talking about two things. 1. Power on idle. 2. Power consumption at normal listening volumes and maximum outputs. And the person mentioned where this is truly useful are: People who are somehow off the grid and have limited electric capacity. And therefore absolutely do need to calculate at least one of these things. So here I am asking if such a person exists on this forum? All this discussion and I want to know....who are these people that need to know? And if there is some other type of person where this information is needed .... is there such a person on this forum where this info is useful? Would they care to make themselves known and talk to us?
You have repeatedly shown little or no interest in power usage, if anyone starts a thread about leaving equipment on or off, you practically brag about never turning it off, claiming it sounds better (whether it does is irrelevant to this discussion). I wouldn’t expect you to appreciate this, and if you don’t understand after everything that’s been written then I don’t think you’re going to get it. I care what milage my car gets — after it meets my other needs — I care how much power my refrigerator/television/computer/processor/light bulbs/etc uses — after they meet my other requirements — why shouldn’t I want to know how much my power amp uses — after it meets my other requirements. It seems many want to frame the conversation around why it doesn’t matter to them, claiming you should just care what it sounds like, whether it has enough power, that the power use is minimal compared to other things; or the conversation migrates to what technology is most efficient or that we should just buy different speakers. Some even imply we’re not smart enough to understand the specs. To me there are several possible benefits to users: knowing the minimal constant draw of an individual piece of gear (and thereby the entire system), knowing the average or maximum power an individual piece might draw (power amps likely being the highest power draw for most systems), and knowing the efficiency of a power supply to judge claims made by manufacturers (Gary’s primary premise). Having this information doesn’t mean we are going to choose a piece of gear based on how much power it uses; though if two pieces of equipment sound good, meet your needs, and are about the same price — but one idles at 20% of the other and averages twice the efficiency — then that’s the one I want to buy. I don’t expect you to have the same values as me, that’s fine, but I want to reduce all of the resources I use, which for me are primarily gasoline, propane, well water, and power (which includes how it’s generated). I don’t claim to be a good green citizen and am surely far from it, but I’ll continue to try and get better, this is one small way. For me it’s not about affordability (though I don’t like to waste money), and my home has more power and circuits than I will ever use. I don’t plan on going off the grid, though I might want to be able to power my home on solar and batteries someday (and in summer I have to use AC to get rid of the excess heat). I don’t see wanting to know power consumption and efficiency any different than wanting to know power output, distortion, circuit topology, available inputs, binding posts, size, weight, or color. Not everything we want to know has anything to do with how an amp sounds, even if that is someone’s primary criteria. Hopefully I’ve given you one perspective on why this information is important to some, at least to me. I’ll add that I won’t buy another multichannel amp without knowing idle power and something about efficiency. If I have to write the manufacturer to get the information then fine (as long as they answer), but I’d rather read it on the spec sheet along with everything else (and many already do include some of this). Is that really too much to ask? I don't think it's wrong to know the specs of your amps or wonder about idle power usage. Everybody chooses things in their own way. However, power efficiency of the amps - to me - seems like a very inconsequential matter considering we listen at just a few watts anyway. So let's say a switching amp does much better efficiency at 200 watts output, it means very little in actual power consumption. So I could - sort of - see the interest in idle power usage - as imo that's pretty much what the amps are going to be using anyway. For me, though, I don't think it warrants anything more than a cursory glance. Looking at the data you can see that most class A/B amps idle at about the same power. About the power of one or two old fashion light bulbs or a fan. Usually somebody concerned about power usage will turn their amps off anyway, so the real energy consumed is trivial. If you use central ac or a dryer or dishwasher, you'll be consuming exponentialyl more power than your amps. To put it in perspective, a central ac unit running for say 20 minutes is probably going to consume more power than your amp will over an entire day pf normal use - or three. (I don't have the data to back this up, but judging by what I know about power consumption of AC's and similar appliances, I think I'm right). I think if you put it overall, choosing an amp by power efficiency is probably a bad way to choose - unless you think all amps sound the same. If so....there are some excellent low power lost cost amps out there. For me, sound quality is paramount, and more important than some minor power use. But that's me. I'm not here to tell you what you should consider important. Nothing wrong with asking the manufacturer. But if they start publishing power efficiency data - I think it could mislead tons of people. It would mean bad PR for the company. Imagine how bad the power efficiency data on a set of XPR-1's is going to look - even though in terms of cost it's really not making a large difference. And it definitely doesn't show the overall reason for the performance. Now I assume that it's not cost that worries you but more being green. If so, the Mola mola Kaluga has absolutely incredible performance, and as you can see very low power consumption. It's incredibly pricey, but it's probably one of the best amps out there in terms of performance. Also some of those hypex amps will probably be very low power consumption as well. We've seen a lot of discussion about power efficiencies and it looks like we are talking about two things. 1. Power on idle. 2. Power consumption at normal listening volumes and maximum outputs. And the person mentioned where this is truly useful are: People who are somehow off the grid and have limited electric capacity. And therefore absolutely do need to calculate at least one of these things. So here I am asking if such a person exists on this forum? All this discussion and I want to know....who are these people that need to know? And if there is some other type of person where this information is needed .... is there such a person on this forum where this info is useful? Would they care to make themselves known and talk to us? Sorry for replying so slowly but I was asleep, it was night time in my time zone. I'm not off the grid, but I'm most certainly interested to know (as I have mentioned in several posts) whether or not I can fit an XPA-1 Gen 1 or 2 power requirements into the circuit to replace the XPA-100? Or if I'd be better off waiting for an XPA-1 Gen 3 with its lower power draw potential? Cheers Gary Is it a circuit thing? Like you only have that line and it's already being used by a ton of devices? The XPA-1 gen 2 consumes huge amounts of power. I currently use a lot of devices on the same 15 amp line. And it is a definite concern of mine. What I plan to do is get an additional line run out for the amps. Because they do consume huge amounts of power in the mode I like to run them in (class A). And on occassion the meter on my equipment shows that there've bee occassional voltage sags. I know if I run a video game on my computer while running all my other equipment I could risk shut down by using up all the curret on the line. If you have the spare cash, running a new line would definitely be my reccomendation. Having said that, I really doubt the ge 3 units consume anywhere near that power. The gen 2 XPA-1 is meant to consume that power by design. That's the point of class A. But I've heard very little about class A from the gen 3 units. But if it is a cost saving thing - simply buying a new amp to save money on power is a huge lose lose proposition. You'll never save money that way because of the (relatively) trivial amount of current to cost your current amps are using. |
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Post by garbulky on Oct 11, 2017 9:56:58 GMT -5
So from the brief conversations I've had
I can conclude that
On this forum at least -
There are no people who actually NEED an amps power efficiency data - or idle power consumption to make a decision. I.e. off the grid people with limited power capability. So the whole discussion about these people needing it seem to be like talking about the mythical unicorn. It doesn't exist.
What I see is simply people that are curious about it but not with any urgent pressing need for Emotiva to include it - though they do have some reasons for being interested.
I think they shouldn't include it - not to suppress data - but things like power efficiency would simply confuse the majority of people in how it would really affect them. "What? This amp is only 2% efficient? Jesus! No thanks." That type of reaction. But I also don't think they should hide it from people that would say email them and ask.
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Post by bumpytrail on Oct 11, 2017 11:23:29 GMT -5
Apologize if this has already been mentioned but amplifier(s) required initial start up power is more important to me as I have tripped my house circuit breakers on turning on my home theater system. With a big screen TV, Emotiva Gen 1 XPA-3 and XPA-5 Amps, receiver; along with other house hold current sucking devices; computers, laser printers, blow dryers, curling irons, microwaves, power tools, air compressors etc... in the house. Just my 2 cents... fwiw.
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Post by AudioHTIT on Oct 11, 2017 12:21:05 GMT -5
So from the brief conversations I've had I can conclude that On this forum at least - There are no people who actually NEED an amps power efficiency data - or idle power consumption to make a decision. I.e. off the grid people with limited power capability. So the whole discussion about these people needing it seem to be like talking about mythical unicorns. It doesn't exist. The only person I know that wants to be off the grid (dyohn) thinks the whole idea of amps factoring in to it is somewhat silly. What I see is simply people that are curious about it but not with any urgent pressing need for Emotiva to include it. I think they shouldn't include it - not because I like to suppress data - but things like power efficiency would simply confuse the majority of people and mislead them from how it would really affect them. "What? This amp is only 2% efficient? Jesus! No thanks." that type of reaction. That kind of PR is just bad - and pointless too from a consumer's actual practical usage and cost perspective. But I also don't think they should hide it from people that would say email them and ask. This and your previous post again try to shift the conversation back to reasons people shouldn’t care about power usage because you don’t . Of course people don’t “need” it, many of us have been buying amplifiers for over 50 years without this information, no one said they ‘need’ it. I have said I want idle power information first because from what I’ve seen it does stabilize, and despite Keith’s assertion that it’s a moving target could still be easily taken and given within a few % at little or no cost (maybe it should be called “Average Power Consumption at Idle). I agree with your comment that most listening is done with very little power, which is the main reason I think idle power is helpful, the amp is usually (almost) idling (NP’s First Watt), and this number represents a typical draw under many conditions. I have said I wouldn’t buy another multichannel amp without this information (which I expect to do within the next year), so I am more than “curious”. Then you take on DYohn’s argument that people aren’t smart enough to understand the spec(s). Does everyone understand power, THD, IM, SNR, damping factor, slew rate, etc.? Should we get rid of those too because they’re often misunderstood — I wonder how many times Dan has rolled his eyes because someone posted something like “oh wow, bummer, I wanted that Emo amp but it only has 180 Watts and I really need 200”, or “I’m getting the BoguSpec 500 because it has 0.001% distortion and the Emotiva’s only 0.005%”. If those people are lucky they join a well rounded forum (like the Lounge) and express their concerns, hopefully they get some good advice on when something’s important and when it just becomes specsmanship. Shouldn’t someone be made aware of how much power a XPA-1 consumes while in Class A mode, or A/B for that matter? If they don’t understand the significance can’t they ask like they do now with the other specs? And now that Emotiva has increased their efficiency (as shown by measurements posted here), shouldn’t they get the advantage of comparing very favorably to other Class A/B amps, even in the ballpark of some Class D amps? I think all most of us can educate ourselves and evaluate the value of these numbers, and they should include them in the specs for all products (or at least amplifiers). You also imply the Lounge represents the sentiments of all Emotivans (Emotivians?), because there aren’t enough supportive posts in this thread you say that no one needs or wants this information. At the moment there are 25 members online and 64 guests, do you speak for those guests (or members) who just read what we write? Might some of them be interested in this topic or information related to it? As we are discussing this issue, some will just read and possibly decide they want to know more. |
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Post by AudioHTIT on Oct 11, 2017 12:38:56 GMT -5
Apologize if this has already been mentioned but amplifier(s) required initial start up power is more important to me as I have tripped my house circuit breakers on turning on my home theater system. With a big screen TV, Emotiva Gen 1 XPA-3 and XPA-5 Amps, receiver; along with other house hold current sucking devices; computers, laser printers, blow dryers, curling irons, microwaves, power tools, air compressors etc... in the house. Just my 2 cents... fwiw. I think that’s a good point and would be helpful if it could be easily gathered (and it fits right in to my Apollo 13 story!) However I think that “Initial Surge Power” (or current) might be difficult to capture, but maybe not. A workaround that could be helpful would be how to use triggers to stagger the power on surge your system creates. (and thanks, you reminded me I need to fix a small leak in an air line that’s causing my air compressor to come on at random times) |
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Post by leonski on Oct 11, 2017 12:46:31 GMT -5
While an A/B amp MIGHT be as high as 60% efficiency, don't count on that in real use. Power at idle is added to output/efficiency so at very low powers your efficiency is STILL very low. Probably no more than 20->25% if that.
An amp (mythical) which idles @50 watts and uses and additional 25 watts for a 2x7 watt output is still only 14/75=18.67% efficient.
Keith says that idle power can vary but doesn't elaborate: Things warm as they sit at idle. Transformer will rise a few degrees. Caps become charged. Various resistors and Thermisters (temp sensitive resistor) all change as they warm
One amp from years gone by even had an input section which definiately got better when warm. Transistors change characteristics and some measurables when warm VS cold.
The Biggest Monos might even have a 30amp or greater turn-on surge. That's gonna last a couple cycles, at most, before settling down.
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Post by garbulky on Oct 11, 2017 12:47:10 GMT -5
So from the brief conversations I've had I can conclude that On this forum at least - There are no people who actually NEED an amps power efficiency data - or idle power consumption to make a decision. I.e. off the grid people with limited power capability. So the whole discussion about these people needing it seem to be like talking about mythical unicorns. It doesn't exist. The only person I know that wants to be off the grid (dyohn) thinks the whole idea of amps factoring in to it is somewhat silly. What I see is simply people that are curious about it but not with any urgent pressing need for Emotiva to include it. I think they shouldn't include it - not because I like to suppress data - but things like power efficiency would simply confuse the majority of people and mislead them from how it would really affect them. "What? This amp is only 2% efficient? Jesus! No thanks." that type of reaction. That kind of PR is just bad - and pointless too from a consumer's actual practical usage and cost perspective. But I also don't think they should hide it from people that would say email them and ask. This and your previous post again try to shift the conversation back to reasons people shouldn’t care about power usage because you don’t . Of course people don’t “need” it, many of us have been buying amplifiers for over 50 years without this information, no one said they ‘need’ it. I have said I want idle power information first because from what I’ve seen it does stabilize, and despite Keith’s assertion that it’s a moving target could still be easily taken and given within a few % at little or no cost (maybe it should be called “Average Power Consumption at Idle). I agree with your comment that most listening is done with very little power, which is the main reason I think idle power is helpful, the amp is usually (almost) idling (NP’s First Watt), and this number represents a typical draw under many conditions. I have said I wouldn’t buy another multichannel amp without this information (which I expect to do within the next year), so I am more than “curious”. Then you take on DYohn’s argument that people aren’t smart enough to understand the spec(s). Does everyone understand power, THD, IM, SNR, damping factor, slew rate, etc.? Should we get rid of those too because they’re often misunderstood — I wonder how many times Dan has rolled his eyes because someone posted something like “oh wow, bummer, I wanted that Emo amp but it only has 180 Watts and I really need 200”, or “I’m getting the BoguSpec 500 because it has 0.001% distortion and the Emotiva’s only 0.005%”. If those people are lucky they join a well rounded forum (like the Lounge) and express their concerns, hopefully they get some good advice on when something’s important and when it just becomes specsmanship. Shouldn’t someone be made aware of how much power a XPA-1 consumes while in Class A mode, or A/B for that matter? If they don’t understand the significance can’t they ask like they do now with the other specs? And now that Emotiva has increased their efficiency (as shown by measurements posted here), shouldn’t they get the advantage of comparing very favorably to other Class A/B amps, even in the ballpark of some Class D amps? I think all most of us can educate ourselves and evaluate the value of these numbers, and they should include them in the specs for all products (or at least amplifiers). You also imply the Lounge represents the sentiments of all Emotivans (Emotivians?), because there aren’t enough supportive posts in this thread you say that no one needs or wants this information. At the moment there are 25 members online and 64 guests, do you speak for those guests (or members) who just read what we write? Might some of them be interested in this topic or information related to it? As we are discussing this issue, some will just read and possibly decide they want to know more. I agree the XPA-1s number would be useful to know for circuit loading. They use substantial idle power. I really doubt Emotiva amps are going to operate favorably to class D amps in efficiency. Class D amps are very efficient. Emotiva simply uses a switching power supply. Their blades are class A/B. I guess the point is they claim it's more efficient - where is the data? I agree they haven't provided it. But for me it's a shrug. It makes sense to me that it's more "efficient" as switchers often tend to be. Maybe they don't know either. They might have assumed as well without hard evidence. Anyway, why I talked about people off the grid was because of the discussion about it. (from Pknaz) Gary I frankly thought that was the only really valid reason to figure out things like idle power consumption and efficiency. If your house is limited in power output, this would matter. The other reasons are more confusing to me. So I thought somebody here may be one of those people hence the reason for the thread. Hence my question. Anyway, as to censuring the information, which I am reccomending, you are saying why not treat consumers as intelligent? Because this is going to sound terrible. Because they are not you who take time to figure things out. They also don't give the benefit of the doubt when they don't understand something. This can hurt sales. This is the reason I also protested against Emotiva implying a multichannel amp having a powerful all channels rating in the gallery when clearly once you dig in, you see it is only a two channels rating and the all channels rating is much less. Because people will not read and be mislead. (Thankfully Emotiva sensibly corrected this). It's a business, and Emotiva doesn't want to be the few companies volunteering confusing info right? I mean volunteering THD - that's fine. Because even if another amp has less, the score is still great right? It's used to evaluate the audio quality of an amp. Five way binding posts - build quality and value. Power efficiency - I still can't see how it wouldn't confuse everybody. Right now people think of power efficiency as 60% at full power. But that;s not reality that mattters for power efficiency. The reality is more like 1-2 watts for people that are actually interested in it. The peaks only happen occassionaly. So providing that number would sound really bad. But lot of people don't even know why that value is even provided. I dare so there's no amp companies that provide a 1 to 2 watt value. Only a full power value. I think Emotiva would be hurting themselves making it publicly available. But I see no problem making it available through email. |
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Post by teaman on Oct 11, 2017 12:53:11 GMT -5
Garbulky, unless your post and info is relegated to the XPA-1's the other X series amps use Class H now.
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Post by garbulky on Oct 11, 2017 12:58:45 GMT -5
Garbulky, unless your post and info is relegated to the XPA-1's the other X series amps use Class H now. You know, I am confused now. From what I gather the amps power supply are class H. But the power supply on the gen 3 is a switching supply. Not sure how they are both. Maybe I'm saying it wrong. Maybe they are both somehow |
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Post by AudioHTIT on Oct 11, 2017 13:11:26 GMT -5
... I really doubt Emotiva amps are going to operate favorably to class D amps in efficiency. Class D amps are very efficient. Emotiva simply uses a switching power supply. Their blades are class A/B. I’m aware Emo amps are A/B and I wouldn’t have made the claim if I didn’t think it was true. From geebo’s measurement we have an XPA-2 G3 idling @ 20W, from the Wyred4Sound spec sheet we have the ST mk II idling @ 28W. Two stereo amps, the Emo is 300 WPC Class A/B, the W4S is 250 or 500 WPC Class D; I think the Emo ‘compares favorably’ for Idle Power (which I’m arguing they should include now, as we’ve shown others have done). |
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Post by garbulky on Oct 11, 2017 13:54:20 GMT -5
... I really doubt Emotiva amps are going to operate favorably to class D amps in efficiency. Class D amps are very efficient. Emotiva simply uses a switching power supply. Their blades are class A/B. I’m aware Emo amps are A/B and I wouldn’t have made the claim if I didn’t think it was true. From geebo’s measurement we have an XPA-2 G3 idling @ 20W, from the Wyred4Sound spec sheet we have the ST mk II idling @ 28W. Two stereo amps, the Emo is 300 WPC Class A/B, the W4S is 250 or 500 WPC Class D; I think the Emo ‘compares favorably’ for Idle Power (which I’m arguing they should include now, as we’ve shown others have done). Wow I am sorry. I totally overlooked that. That is not what I would have expected at all. You are right there. They can compare favorably then. |
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Post by kybourbon on Oct 11, 2017 15:37:29 GMT -5
Most people can rent a Kill-A-Watt from the public library for free.
What not make a crowd sourced list of idle power and peak power of each of the Emotiva products? I think that way you cut out the middle man.
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Post by garbulky on Oct 11, 2017 15:46:34 GMT -5
kybourbon I don't have the device. I don't know where I would rent one free. My library does not do it. The Lafayette library in LA however does have one. I may be able to setup an interlibrary loan though I may not be allowed to as it is not a book. But if I had one, I would be willing to provide a result for you guys. I'd do one at standby in A and AB mode. And also I'd do one with loud music (within reason in my townhouse) playing. I may also be able to provide the number of dots that light up as well. Though keep in mind my speakers are 4 ohms not 8 ohms which the lights are calibrated for. I can also in comparison do one with the Mini-x a-100 as well - headphones only.
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Post by leonski on Oct 11, 2017 17:14:20 GMT -5
Garbulky, unless your post and info is relegated to the XPA-1's the other X series amps use Class H now. You know, I am confused now. From what I gather the amps power supply are class H. But the power supply on the gen 3 is a switching supply. Not sure how they are both. Maybe I'm saying it wrong. Maybe they are both somehow 'H' is a tracking or multi-voltage rail PS and can be of conventional or Switcher design. The switcher might be slightly more efficient and weigh less for shipping purposes. Someone from EMO claimed they were less expensive, too. 'H' isn't going to be the 'killer app' for efficiency. This will still be driven by OUTPUT and BIAS. Output meaning an A or A/B amp. A High Bias design like some of the G2 stuff will consume a fair amount of juice at idle. A low-bias A/B design which might be a couple watts in 'A' before 'sliding' into A/B will use less power. And both could have an 'H' / Switcher PS. |
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Post by AudioHTIT on Oct 11, 2017 17:19:25 GMT -5
Most people can rent a Kill-A-Watt from the public library for free. What not make a crowd sourced list of idle power and peak power of each of the Emotiva products? I think that way you cut out the middle man. I agree, we have a good start on Emotiva Amps above, but it would be nice to fill out the list with as many Emo products as possible. It’s great to have other gear as well, and if you’re going to the trouble of measuring your amp then why not get as much as possible at the same time. Edit: I should add that getting peak power will be difficult and hard to reproduce, it also might encourage someone to push their system beyond what’s safe and damage something (most likely their speakers). Unless someone knows an easy and safe way to get peak power with a K-O-W, I’d recommend we stick to idle power.
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Post by Gary Cook on Oct 11, 2017 18:31:04 GMT -5
Personally I think displaying efficiency as a simple % (or even %'s) is pretty much useless to the end user. It may well be a selling point comparison that amplifier manufacturers can brag about, "ours is more efficient than yours". But far more useful would be listing the power draws at the common 5 data points, standby, idle, 1 watt, 20% of maximum output and maximum output. That way prospective customers can make informed decisions on whether or not an amplifier will have sufficient input power in their environment.
For user testing, I'd ignore the maximum power measure and confirm that the 20% output can be handled by the speakers. None of which is an issue for the manufacturer as they have the facilities for testing/measuring the full range of outputs.
Power draw in watts is the best measure as that way different voltages in different countries can be accounted for.
Cheers
Gary
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Post by leonski on Oct 11, 2017 18:36:41 GMT -5
Most people can rent a Kill-A-Watt from the public library for free. What not make a crowd sourced list of idle power and peak power of each of the Emotiva products? I think that way you cut out the middle man. I agree, we have a good start on Emotiva Amps above, but it would be nice to fill out the list with as many Emo products as possible. It’s great to have other gear as well, and if you’re going to the trouble of measuring your amp then why not get as much as possible at the same time. Edit: I should add that getting peak power will be difficult and hard to reproduce, it also might encourage someone to push their system beyond what’s safe and damage something (most likely their speakers). Unless someone knows an easy and safe way to get peak power with a K-O-W, I’d recommend we stick to idle power.
I've been thinking about that. the K-O-W is not a 'fast' enough meter to catch and hold peaks. So the next best thing would be test tones. Lots of power will fry a tweeter, especially if applied for too long, to keeping the tone to maybe 1khz will help. And for no longer then it takes to get the data. Say 15 seconds or so. And <5 seconds at higher powers. Give tweeter time to COOL between tests of this nature. The data I'd want to see would be: 1. Line Voltage @idle and during test. This will kind of show how 'stiff' the power line is. 2. Idle and during test 'Watts'. and 3. Power Factor. This will show how reactive the power supply is and allow calculation of VA vs Watts. As for 'Maximum' or 'Peak' power? I'd never ask or recommend turning it 'up' drastically with test tones. It might be a good idea to have an SPL meter standing by. I've seen Smart Phone apps, but don't know how repeatable or accurate they are. Speakers aren't designed for sustained test tones. Testers use 'tone burst' techniques which limit test time to very short intervals. The BEST way to determine peak power draw would be to hook the amp up to a Dummy Load, skipping the speaker part. Worst case here is heating up your room, but of course, you COULD pop a fuse or otherwise damage your amp. Even Better? Find someone with an O-Scope who wants to help with some dynamic measurments. |
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Next up, I will present my "efficiency calculator"...where you can model the efficiency of each component in your system and determine an overall level. Prepare to be disappointed in what energy wasters we all are!
