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Post by AudioHTIT on Oct 7, 2017 1:16:04 GMT -5
I don't see any reason whatsoever to "suppress" anything that anyone wants to talk about. And we're always interested in listening to what customers and fans have to say. (Note that I'm also not specifically promising to answer every question either.) That’s great! However, I will note two things....... First, there's effectively no such thing as "efficiency while idling". When an amplifier is running, not in standby, but not delivering any output signal, its efficiency is zero. (Power is going in and no power is coming out.) Therefore, the meaningful term would be "power consumed while idling". I agree, “Power consumed while idling” seems the perfect term to be used on a spec sheet. I’ve been using “Idle power”, which I think is sufficient for general conversation. The other thing is that, with most modern amplifier designs, circuitry is included that automatically adjusts the bias to maintain other more important performance parameters. So, if you were to measure most of our Class A/B amps with no input signal, you would find that the amount of power they consume will vary considerably - depending on factors like how warm they are. These automatic adjustments are designed to make sure that distortion and noise remain low, and even to ensure that the amp "warms up" quickly, but doesn't overheat after that. However, the exact amount of power the amp consumes as a result is considered to be an unimportant side effect (within certain limits). In order to provide meaningful numbers there, we would have to take a lot of measurements, and then figure out how to present them in a meaningful way. To be blunt, since there is no industry standard for presenting those measurements, and very few people either publish or ask for them, we usually don't bother to measure them. ... I’m going to have to push back on that, I don’t think it is or needs to be that complex, and as has been proposed could be done along with other testing. However I will grant you that there are no industry standards, which is a premise of this thread. ‘Power consumed by idle’ could be taken before tones are applied for other testing, I assume the amps are allowed to idle for some time first and this seems an easy time to take a quick reading - I would like to see this for all products, not just amps. Signal to noise measurements are taken at rated power, and at 1 Watt; this would seem a good time to grab another reading on power consumption, which could then be used to compute ‘efficiency’ at those power levels. I believe this corresponds to Gary’s suggestions, though he might have mentioned a third reading. Obviously those who test your amps know what they’re doing and when these readings could be taken, we don’t want to add any significant amount of work or time, and I really don’t think it would have to. Like the other specs Emotiva publishes, they only have to be taken once. Again, the point of this thread is that there is no information to research, manufacturers don’t provide idle or efficiency ratings. And why is an Internet thread a bad place to promote adding another spec to equipment ratings? Isn’t that what forums are for? I just don’t think information is silly, I’m baffled why anyone would make an effort to suppress it. |
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Post by AudioHTIT on Oct 7, 2017 8:15:21 GMT -5
As I was writing my last post I remembered seeing efficiency ratings somewhere, as I finished I remembered where. Here are some spec snippets from one of Wyred4Sound’s amps (a large monoblock). I’m not trying to promote another product here, just give an example that at least one vendor is giving idle and efficiency specs (they even use the exact term Keith proposed for idle).
* Typical THD+N 8Ω (10W out): 0.0055%
* Power Output 8Ω @ 0.2% THD+N: 570W
* Power Output 8Ω @ 1.0% THD+N: 625W
* Power Output 4Ω @ 0.2% THD+N: 1,140W
* Power Output 4Ω @ 1.0% THD+N: 1,225W
...
* Efficiency 4Ω: 79% @ 1000W
* Efficiency 8Ω: 78% @ 500W
...
* Idle Power Consumption: 15W
As Gary has suggested additional efficiency points would be nice, they also don’t give all these specs consistently, some amps don’t have efficiency, some also give standby power. Anyway it shows that it’s not far fetched to hope these specs could make their way into more products.
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Post by pknaz on Oct 7, 2017 10:57:00 GMT -5
Maybe I'm really missing something here. Why is this important again?
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Post by AudioHTIT on Oct 7, 2017 12:39:41 GMT -5
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Post by leonski on Oct 7, 2017 12:45:12 GMT -5
As I was writing my last post I remembered seeing efficiency ratings somewhere, as I finished I remembered where. Here are some spec snippets from one of Wyred4Sound’s amps (a large monoblock). I’m not trying to promote another product here, just give an example that at least one vendor is giving idle and efficiency specs (they even use the exact term Keith proposed for idle). * Typical THD+N 8Ω (10W out): 0.0055% * Power Output 8Ω @ 0.2% THD+N: 570W * Power Output 8Ω @ 1.0% THD+N: 625W * Power Output 4Ω @ 0.2% THD+N: 1,140W * Power Output 4Ω @ 1.0% THD+N: 1,225W ... * Efficiency 4Ω: 79% @ 1000W
* Efficiency 8Ω: 78% @ 500W
...
* Idle Power Consumption: 15WAs Gary has suggested additional efficiency points would be nice, they also don’t give all these specs consistently, some amps don’t have efficiency, some also give standby power. Anyway it shows that it’s not far fetched to hope these specs could make their way into more products. Again, No standards exist or how the above measures were taken. It would appear that the data is similar to what is quoted by B&O with the ASP module series. 'D' amps have some other problems which I won't go into here, not the least of which is very low long-term power, compared to the ratings. Does W4S continue to use B&O modules? |
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Post by klinemj on Oct 7, 2017 13:14:07 GMT -5
I understand that some feel it would be good to have...and I respect that. For me, even if they did publish the spec - it's not something that would sway my decision. And, frankly, there would be people sweating the fact that, on paper, "this amp looks like it should sound better, but it's 0.2% less efficient than that one which likely sounds a bit worse...what should I do?" I'd have to avoid even looking at those threads (and we KNOW they would pop up...). Mark |
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Post by AudioHTIT on Oct 7, 2017 13:24:39 GMT -5
As I was writing my last post I remembered seeing efficiency ratings somewhere, as I finished I remembered where. Here are some spec snippets from one of Wyred4Sound’s amps (a large monoblock). I’m not trying to promote another product here, just give an example that at least one vendor is giving idle and efficiency specs (they even use the exact term Keith proposed for idle). * Typical THD+N 8Ω (10W out): 0.0055% * Power Output 8Ω @ 0.2% THD+N: 570W * Power Output 8Ω @ 1.0% THD+N: 625W * Power Output 4Ω @ 0.2% THD+N: 1,140W * Power Output 4Ω @ 1.0% THD+N: 1,225W ... * Efficiency 4Ω: 79% @ 1000W
* Efficiency 8Ω: 78% @ 500W
...
* Idle Power Consumption: 15WAs Gary has suggested additional efficiency points would be nice, they also don’t give all these specs consistently, some amps don’t have efficiency, some also give standby power. Anyway it shows that it’s not far fetched to hope these specs could make their way into more products. Again, No standards exist or how the above measures were taken. It would appear that the data is similar to what is quoted by B&O with the ASP module series. 'D' amps have some other problems which I won't go into here, not the least of which is very low long-term power, compared to the ratings. Does W4S continue to use B&O modules? Yes, there are no standards, and again that what this thread is trying to promote. What this shows however, is that there are manufacturers - and presumably their customers - who find this information useful. There was a time when there were no standards for measuring power or distortion, but some manufacturers made outrages claims and standards and regulations were established. I clipped the specs above not wanting to promote another manufacturer here, you can find details on their site, here’s what they say about the modules in the amp above: Powered by ICEpower® (ASP) |
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Post by leonski on Oct 7, 2017 15:59:50 GMT -5
I wanted to make a few notes on efficiency. First? Everyone buys into efficiency = 100* (Pout / Pin). This yields a simple 'percentage'. So? This is wrong in every case except for a straight, non-inductive resistor. Maybe for an incandescent lightbulb, too? All Power Supplies 'look' in large part like either a capacitor or inductor to the power company, have what is known as Power Factor. All those inductors and transformers are very 'reactive'. It is possible for 2 amps which have the same output to have drastically different draws from the power line. Even IF they measure the same watts, the one with the lower power factor will load the line more. Just going by watts, they'd have the same efficiency, but that's not correct. The amp with the higher VA rating would be the one with lower efficiency. Good luck getting this information from a manufacturer. A few builders make claims for 'power factor correction' of the power supplies of amps. jeffrowlandgroup.com/kb/categories.php?categoryid=16A trivial example: My 40 watt fluorescent tube by my desk? Right now, line voltage is about 118vac. My Kill-A-Watt reads 38va / 31watts and a PF (Power Factor) of 0.80 What is going on these days is that power companies will impose a SurCharge on larger power users for Low Power Factor. The day is coming when home users could be dinged for poor power factor. Look at the new generation of smart meter. You can now easily have differential rates based on time of day. It's not a stretch for the power company to ask for some kind of 'averaged' power factor number to be applied and bill YOU accordingly. While 'green' is both a good idea and the coming thing, it won't be without cost. Equipment with Power Factor Correction will cost more. Electric bills for consumers may end up with a Low Power Factor surcharge. Stay Tuned: |
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Post by Gary Cook on Oct 8, 2017 2:52:22 GMT -5
I wanted to make a few notes on efficiency. First? Everyone buys into efficiency = 100* (Pout / Pin). This yields a simple 'percentage'. So?This is wrong in every case except for a straight, non-inductive resistor. Maybe for an incandescent lightbulb, too? All Power Supplies 'look' in large part like either a capacitor or inductor to the power company, have what is known as Power Factor. All those inductors and transformers are very 'reactive'. It is possible for 2 amps which have the same output to have drastically different draws from the power line. Even IF they measure the same watts, the one with the lower power factor will load the line more. Just going by watts, they'd have the same efficiency, but that's not correct. The amp with the higher VA rating would be the one with lower efficiency. Good luck getting this information from a manufacturer. A few builders make claims for 'power factor correction' of the power supplies of amps. jeffrowlandgroup.com/kb/categories.php?categoryid=16A trivial example: My 40 watt fluorescent tube by my desk? Right now, line voltage is about 118vac. My Kill-A-Watt reads 38va / 31watts and a PF (Power Factor) of 0.80 What is going on these days is that power companies will impose a SurCharge on larger power users for Low Power Factor. The day is coming when home users could be dinged for poor power factor. Look at the new generation of smart meter. You can now easily have differential rates based on time of day. It's not a stretch for the power company to ask for some kind of 'averaged' power factor number to be applied and bill YOU accordingly. While 'green' is both a good idea and the coming thing, it won't be without cost. Equipment with Power Factor Correction will cost more. Electric bills for consumers may end up with a Low Power Factor surcharge. Stay Tuned: What % of people will say "I don't have a smart meter so I don't care". Here in Oz it's generally accepted to insist on "dumb metres", the only people who have smart metres are the ones with solar power. How does the smart metre know which piece of equipment has power correction, for example I have 4 pieces (higher power draw) of audio/video gear on one circuit and 7 pieces (lower power draw) on another. It would have to be a pretty smart smart meter to know which one has power correction. Cheers Gary |
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Post by leonski on Oct 8, 2017 12:12:16 GMT -5
I found out about PF when I bought the Kill-A-Watt and wondered just what the heck it was 'measuring'.
IMO, if people want EMO to report efficiency, then PF is fully part of the deal.
The general rule is you get billed for KwH and use VA.
PF is not going to be trivial in the future. Power companies can surcharge their biggest users IF the PF drops below maybe 0.80 or so.
Eventually we ALL may be on the hook for either higher rates across the board or dinged for an anti-social PF.
My point was that those concerned with 'efficiency' should actually know something about it. PF is part of the deal.
I know most here are loath to part with 20$ for a meter. I get it. But for those few who somehow 'require' efficiency data? Report it all.
Here in the States, many electric utilities are changing to smart meters. Mine reports usage WIRELESSLY to the service. No more 'meter man'.
It isn't a far stretch to see the future of ever more detailed reporting. Everything from usage by hour and appropriate rates to Power Factor is on the table.
And Gary? I don't necessarily DIS agree with you. Smart Meters can be intrusive. For the first 6 months I put Tin Foil over mine and would find it GONE
on about a weekly basis. I tried telling the Power Company it gave me a Headache. No Go.
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Post by novisnick on Oct 8, 2017 13:52:11 GMT -5
I haven’t read the entire tread but here is some input.
My XPR-1’s have been shut down over night and I have a kilowatt meter attached to the pair. Ive now turned them on and they are energizing the capacitors I think.
Off, the amps consumed > 1 watt
powered On they’ve been climbing for a few minutes.
Up to 362 watts for the pair
181 watts per amp at idle at the moment
No other gear on this line and system is off
UPDATE;
Speakers at 8’ and an increase of 30 watts per pair of amps had the music at 90 dbs
Directly from Paradigm
Sensitivity Room / Anechoic
92 dB / 89 dB
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Post by leonski on Oct 8, 2017 15:11:43 GMT -5
GOOD! Some more real data.
Get enough of that and it'll all start making sense. But just given total consumption NEAR 400 watts and the speakers 90db output, I'm guessing
a very low efficiency. 8 watts out (4 per speaker) @400 watts IN is only 2%.
The amp will charge the caps in just a few cycles. And might draw an instantanious 30 amps or more. Inrush current limiting can be provided by something as
simple as a Thermister. This is a resistor whose resistance DROPS as it warms. So when the amp is warm and presumably fully charged and running, it has little
restriction to current flow. When stone cold and presumed to be fully dis charged? High resistance limits current flow so you don't 'pop' something.
OK, I'm going to move my Kill-A-Watt to my Parasounds. One at a time, than play some music or watch a movie. I won't bother with 'level', but just to
comfortable. Easy to hear the phone ring or door knock. Give me some time to take some data. I MIGHT drag out the SPL meter and take some steady-state
readings with a 1khz tone.
I REALLY hate climbing around back of the stereo.
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Post by garbulky on Oct 8, 2017 16:06:56 GMT -5
GOOD! Some more real data. Get enough of that and it'll all start making sense. But just given total consumption NEAR 400 watts and the speakers 90db output, I'm guessing a very low efficiency. 8 watts out (4 per speaker) @400 watts IN is only 2%. The amp will charge the caps in just a few cycles. And might draw an instantanious 30 amps or more. Inrush current limiting can be provided by something as simple as a Thermister. This is a resistor whose resistance DROPS as it warms. So when the amp is warm and presumably fully charged and running, it has little restriction to current flow. When stone cold and presumed to be fully dis charged? High resistance limits current flow so you don't 'pop' something. OK, I'm going to move my Kill-A-Watt to my Parasounds. One at a time, than play some music or watch a movie. I won't bother with 'level', but just to comfortable. Easy to hear the phone ring or door knock. Give me some time to take some data. I MIGHT drag out the SPL meter and take some steady-state readings with a 1khz tone. I REALLY hate climbing around back of the stereo. I don't know if it's fair to call the amp not efficient. The XPR-1 is biased in to class A power. I don't know how much but if I had to guess it's 30 watts class A power. So simply maintaining the bias uses up lots of power. So calling it a 2% efficient amp is not exactly looking at all the factors. I guess that's another reason why it's hard to judge "efficiency". For instance at max power the efficiency might be terrible. But what about 90% power? Would the efficiency improve? I see a confusing number. "Don't get the XPR-1, it's got 2% efficiency." Sounds bad right? But not really. It's an excellent amp. |
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Post by leonski on Oct 8, 2017 16:48:32 GMT -5
My (limited) understanding of the amp in question tells me it's a 'high bias' / A- A/B design. The first bit of power is biased heavily to class 'a'. Than as power increases, the bias decreases as a funciton of that increase. To see what or 'how bad' a TRUE and FULLY class 'a' design can get, look at the Pass XS-300 amp which is a 4-piece stereo pair of monos which weigh 600lb or so. And idle at 1000 watts. Each. But don't increase in power usage as demand increases. I'd have 'em if I lived NORTH of the Arctic Circle.
the number I mentioned, @2% was just at that power. As power goes UP, so will efficiency. That's why the 'd' amp folk telling you their amps are'85% efficient' is a red herring. That's at an Unrealistic and Seldom (never, really) full power. Since the XPR-1 s not producing music
when 'idle' but comsuming nearly 350 watts, that is @zero efficiency. All heat and NO music! Here in SoCal? Maybe nice in the Winter?
Efficiency and quality have little or nothing to do with one another. And the efficiency of the amp will Rise to 50% to maybe 60% at very high powers. Another factor to consider in 'how much' power Do I Buy for highly sensitive speakers? But certainly NOT the 'decider'.
Efficiency is on a 'curve' starting @zero efficiency at some 'housekeeping' power and rising as power output rises, at some point it'll flatten out as power continues to rise. I think stereophile tests after pre-running at 1/3 power, which THEY say is 'worst' case' for an A/B amp.
I don't know what that means from an 'efficiency' to 'power' viewpoint. That might be where the curve 'flattens' out?
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Post by Gary Cook on Oct 8, 2017 18:52:24 GMT -5
I haven’t read the entire tread but here is some input. My XPR-1’s have been shut down over night and I have a kilowatt meter attached to the pair. Ive now turned them on and they are energizing the capacitors I think. Off, the amps consumed > 1 watt powered On they’ve been climbing for a few minutes. Up to 362 watts for the pair 181 watts per amp at idle at the moment No other gear on this line and system is off UPDATE; Speakers at 8’ and an increase of 30 watts per pair of amps had the music at 90 dbs Directly from Paradigm Sensitivity Room / Anechoic 92 dB / 89 dB The important take away from this is that Nick can listen to his pair of XPR-1's at 90db and only draw 362 + 30 = 392 / 110 = 3.5 amps. Plenty of head room left of the 15 amps from that power outlet. As a result it would not be unreasonable to advise someone considering buying a pair XPR-1's that it's OK to run them on a 15 amp circuit. In fact both of them on the same circuit. Whereas without the power draw data the response from many would be pretty much along the lines of, "don't do it they need a 20 amp circuit each". If that sort of data was provided by Emotiva I have no doubt that many who were put off buying XPR-1's because of the perceived power draw would have bought them. Higher sales just from providing the data, why wouldn't any power amplifier manufacturer take that opportunity. Cheers Gary |
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Post by klinemj on Oct 8, 2017 19:33:05 GMT -5
I haven’t read the entire tread but here is some input. My XPR-1’s have been shut down over night and I have a kilowatt meter attached to the pair. Ive now turned them on and they are energizing the capacitors I think. Off, the amps consumed > 1 watt powered On they’ve been climbing for a few minutes. Up to 362 watts for the pair 181 watts per amp at idle at the moment No other gear on this line and system is off UPDATE; Speakers at 8’ and an increase of 30 watts per pair of amps had the music at 90 dbs Directly from Paradigm Sensitivity Room / Anechoic 92 dB / 89 dB The important take away from this is that Nick can listen to his pair of XPR-1's at 90db and only draw 362 + 30 = 392 / 110 = 3.5 amps. Plenty of head room left of the 15 amps from that power outlet. As a result it would not be unreasonable to advise someone considering buying a pair XPR-1's that it's OK to run them on a 15 amp circuit. In fact both of them on the same circuit. Whereas without the power draw data the response from many would be pretty much along the lines of, "don't do it they need a 20 amp circuit each". If that sort of data was provided by Emotiva I have no doubt that many who were put off buying XPR-1's because of the perceived power draw would have bought them. Higher sales just from providing the data, why wouldn't any power amplifier manufacturer take that opportunity. Cheers Gary Or...Emotiva could say that for many uses, they can be powered by a 15 amp circuit. Mark |
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Post by novisnick on Oct 8, 2017 20:00:19 GMT -5
The important take away from this is that Nick can listen to his pair of XPR-1's at 90db and only draw 362 + 30 = 392 / 110 = 3.5 amps. Plenty of head room left of the 15 amps from that power outlet. As a result it would not be unreasonable to advise someone considering buying a pair XPR-1's that it's OK to run them on a 15 amp circuit. In fact both of them on the same circuit. Whereas without the power draw data the response from many would be pretty much along the lines of, "don't do it they need a 20 amp circuit each". If that sort of data was provided by Emotiva I have no doubt that many who were put off buying XPR-1's because of the perceived power draw would have bought them. Higher sales just from providing the data, why wouldn't any power amplifier manufacturer take that opportunity. Cheers Gary Or...Emotiva could say that for many uses, they can be powered by a 15 amp circuit. Mark They did guys, they just didn’t stress it as much as you wanted. I would have never considered the XPR series at all if they hadn’t stated that a 20 amp circuit was only needed for testing and that 15 amps would suffice for all but the most demanding speakers. Of course Im a reader and dig into things if it grabs my attention. Sort of like MQA,,,,,,LOL Could they have done a better job? Who couldn’t do a better job in hindsight? |
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Post by garbulky on Oct 8, 2017 20:38:25 GMT -5
Good points. However somebody would also see that all they would need is an amp that draws 3.5 amps for 99% of their needs! Which could be....the mini-x. Or pretty much any cheap avr on the planet. And then Emotiva would be bankrupt.
This is assuming that all amps sound the same - which I disagree with.
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Post by Gary Cook on Oct 8, 2017 21:59:24 GMT -5
They did guys, they just didn’t stress it as much as you wanted. I would have never considered the XPR series at all if they hadn’t stated that a 20 amp circuit was only needed for testing and that 15 amps would suffice for all but the most demanding speakers. Of course Im a reader and dig into things if it grabs my attention. Sort of like MQA,,,,,,LOL Could they have done a better job? Who couldn’t do a better job in hindsight? Is that a fair excuse for making the same mistake again? Learn from it and make it better next time. After all they are claiming better efficiency from the Gen 3's why not support that claim with data that better enables their customers to make a more informed decision. Especially since it involves next to zero cost. Cheers Gary |
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Post by novisnick on Oct 8, 2017 22:28:36 GMT -5
They did guys, they just didn’t stress it as much as you wanted. I would have never considered the XPR series at all if they hadn’t stated that a 20 amp circuit was only needed for testing and that 15 amps would suffice for all but the most demanding speakers. Of course Im a reader and dig into things if it grabs my attention. Sort of like MQA,,,,,,LOL Could they have done a better job? Who couldn’t do a better job in hindsight? Is that a fair excuse for making the same mistake again? Learn from it and make it better next time. After all they are claiming better efficiency from the Gen 3's why not support that claim with data that better enables their customers to make a more informed decision. Especially since it involves next to zero cost. Cheers Gary Agreed my friend. Communication is the foundation of greatness in all endeavors! |
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