geebo
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"Too bad that all the people who know how to run the country are driving taxicabs and cutting hair"
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Post by geebo on Aug 13, 2022 14:31:19 GMT -5
They just tested a 500wpc $7,500 Rotel amp and ran that test at 50wpc or 10% of it's rated output. The same guy tested a Parasound with an output into 4 ohms of 850 watts at a 100 watt level into 4 ohms or under 12% of the rated power. A Parasound amp with an output rating of 300wpc was tested at 50 watts or under 17% The Emotiva rated at 300wpc was tested at 100 watts or 33% of the rated output. Why the inconsistencies? Are they looking for a result then find the means to get there? Dan tested the XPA at 20% which is more than those I listed above. How would those other amps test at a 33% level? We simply don't know, do we. Were those amps using switching ps or class D? I have no idea their reasons why. I’m guessing those amps failed or badly distorted under heavier loads due the design limitations of the above similar to the xpa gen 3. Neither are good reasons though. Those other amps tested well at least at the output level they tested them at. And if the Emo amp had been tested at those levels everyone would be saying how good it did. If we are going to compare amps then they need to be tested under consistent conditions, no? |
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novisnick
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CEO Secret Monoblock Society
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Post by novisnick on Aug 13, 2022 14:35:31 GMT -5
Were those amps using switching ps or class D? I have no idea their reasons why. I’m guessing those amps failed or badly distorted under heavier loads due the design limitations of the above similar to the xpa gen 3. Neither are good reasons though. Those other amps tested well at least at the output level they tested them at. And if the Emo amp had been tested at those levels everyone would be saying how good it did. If we are going to compare amps then they need to be tested under consistent conditions, no? |
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Post by garbulky on Aug 13, 2022 17:31:06 GMT -5
Were those amps using switching ps or class D? I have no idea their reasons why. I’m guessing those amps failed or badly distorted under heavier loads due the design limitations of the above similar to the xpa gen 3. Neither are good reasons though. Those other amps tested well at least at the output level they tested them at. And if the Emo amp had been tested at those levels everyone would be saying how good it did. If we are going to compare amps then they need to be tested under consistent conditions, no? Yes indeed. I agree. |
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Post by leonski on Aug 14, 2022 0:01:13 GMT -5
Well he didn't though. He clearly said he measured it at 60% the power of the stereophile test. So it wasn't the same test that the other amplifiers go through. I'm also not certain that it was measured for as long as he didn't mention that either. They just tested a 500wpc $7,500 Rotel amp and ran that test at 50wpc or 10% of it's rated output. The same guy tested a Parasound with an output into 4 ohms of 850 watts at a 100 watt level into 4 ohms or under 12% of the rated power. A Parasound amp with an output rating of 300wpc was tested at 50 watts or under 17% The Emotiva rated at 300wpc was tested at 100 watts or 33% of the rated output. Why the inconsistencies? Are they looking for a result then find the means to get there? Dan tested the XPA at 20% which is more than those I listed above. How would those other amps test at a 33% level? We simply don't know, do we. If you are talking about 'D' amps, there are a few real reasons. First? Heat sinking is notably lacking in 'D' amps. Next? The output Zobel which takes care of the switching noise can only take so much. I'm not sure, but I'd suspect that ANY amp with a SMPS will have such a network which will effect max power / time...... The 'ratings' for these amps are mostly gas. Not that it matters a LOT, but they will not meet FTC standards for the measurment of power, except at a fraction (as you saw) of 'rated'. Original ASP series from B&O, which IMO is still a good product, was like 30 seconds or 60 seconds at full power..... But the FTC power was WAY down against ratings. You may still be able to find the datasheets for these amps.....They were also interacting with the load so that as impedance varied, so too did the 'db down at frequency' measurement. The consistent measurement everyone would like to see? That would be FTC which has some kind of preconditioning time @ power before max power measures are taken. You can tell a LOT about an amp under those conditions since those lacking sufficient heat sinking will get too hot to touch......Are the EMO amps 'D' or A/B output? |
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geebo
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"Too bad that all the people who know how to run the country are driving taxicabs and cutting hair"
Posts: 24,188
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Post by geebo on Aug 14, 2022 0:40:52 GMT -5
They just tested a 500wpc $7,500 Rotel amp and ran that test at 50wpc or 10% of it's rated output. The same guy tested a Parasound with an output into 4 ohms of 850 watts at a 100 watt level into 4 ohms or under 12% of the rated power. A Parasound amp with an output rating of 300wpc was tested at 50 watts or under 17% The Emotiva rated at 300wpc was tested at 100 watts or 33% of the rated output. Why the inconsistencies? Are they looking for a result then find the means to get there? Dan tested the XPA at 20% which is more than those I listed above. How would those other amps test at a 33% level? We simply don't know, do we. If you are talking about 'D' amps, there are a few real reasons. First? Heat sinking is notably lacking in 'D' amps. Next? The output Zobel which takes care of the switching noise can only take so much. I'm not sure, but I'd suspect that ANY amp with a SMPS will have such a network which will effect max power / time...... The 'ratings' for these amps are mostly gas. Not that it matters a LOT, but they will not meet FTC standards for the measurment of power, except at a fraction (as you saw) of 'rated'. Original ASP series from B&O, which IMO is still a good product, was like 30 seconds or 60 seconds at full power..... But the FTC power was WAY down against ratings. You may still be able to find the datasheets for these amps.....They were also interacting with the load so that as impedance varied, so too did the 'db down at frequency' measurement. The consistent measurement everyone would like to see? That would be FTC which has some kind of preconditioning time @ power before max power measures are taken. You can tell a LOT about an amp under those conditions since those lacking sufficient heat sinking will get too hot to touch......Are the EMO amps 'D' or A/B output? A/B |
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Post by leonski on Aug 14, 2022 1:51:27 GMT -5
A/B, eh? No excuse than. Will the amp do rated poer or NOT? Simple question, on the face of it, but you still should test for Heat Sink ability to let 'er run..... Nothing worse than an amp which decides it's too hot. www.iqaudiocorp.com/pages/FTC-amplifier-power-spec.htmlLooks like this is a brief summary of 'the rule'...... |
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geebo
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"Too bad that all the people who know how to run the country are driving taxicabs and cutting hair"
Posts: 24,188
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Post by geebo on Aug 14, 2022 8:59:57 GMT -5
A/B, eh? No excuse than. Will the amp do rated poer or NOT? Simple question, on the face of it, but you still should test for Heat Sink ability to let 'er run..... Nothing worse than an amp which decides it's too hot. www.iqaudiocorp.com/pages/FTC-amplifier-power-spec.htmlLooks like this is a brief summary of 'the rule'...... The question remains. Why run a certain test on some other brand amps at 10%, 12% and 17% of rated power then run the same test on an XPA-2 at 33% of rated power? |
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Post by AudioHTIT on Aug 14, 2022 10:49:32 GMT -5
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Post by leonski on Aug 14, 2022 13:42:11 GMT -5
Any ..... ANY amplifier power standard which does not make SOME reerence to a 'real' speaker is bogus.
NO speaker is a pure resistive load, and in THAT, at least all amplifiers are measured equally.
But? One you actually hook up some wires TO a speaker? All bets are off and you are dealing with reactance.
Many proposed speaker summy loads are out there. Just Look
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Post by vcautokid on Aug 14, 2022 15:00:37 GMT -5
The Gen 3 is not a class D amplifier or what one reviewer called "chicken watts", or his friend did. Before there was a ring of truth there. But D is getting quite good. I am staying with the AB amps mostly myself. I want another BAS-X to run my speakers Bi-amp. I already have an A2. My Crowns will do center and surrounds from that point. I could care less about what some nobody I don't know or care about says about a product up to a point. I can think of one who is so bought on editorial it is not even funny, YouTube is his business, and has no integrity or care about you. It is just him. No names. Dan and Lonnie could build something awful and this guy would love it. Glad Dan and Lonnie won't. Measurements are great to a point. I love that Amar is doing these. I think after a while I am raw with reviews, and their B.S. that goes along with it. Ultimately, unless you do Measurements or can engineer better than Dan and Lonnie, none of that is going to matter. You will like these amps or not. Simple really. I would to have loved to try one of these, but they are above my pay grade, besides, how much Mac and Cheese are you going to eat otherwise. There is allot of cool stuff out there and here of course. Don't care if Gen 3 may have a perceived bad rap or not. Don't like them? Don't buy them. See not so hard. Tell you what! You want to Schiit on something. How about the Schiit boxes called AVRs are today. They truly suck. So I tell people buy a Preamplifier Processor you want, don't care what you get. Or a legacy receiver with pre outs. My Denon AVR-4802 will spank any Denon made today, and it is about 20 years old! F*ck HDMI switching. Don't need it. You may. I go for the performance and enjoyment. HDMI is barely a player for me. Dan and Lonnie with Gen 3 are making allot of people happy. If the Gen 3 trickled down to my pay grade, I am all over it. Reality says no however. Emotiva is not perfect, but compared with what I am seeing with Denon and Marantz, lately in Home Theater, their 2 channel still represents, you see how the mighty have fallen. Along with Onkyo and Pioneer, formerly good, now just sucks. So the Gen 3 is swinging for the fence, where most others aren't showing up for the game. Final part? F bad raps!   |
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Post by leonski on Aug 15, 2022 1:47:03 GMT -5
You've got 2 major PS configuraitons.......Linear and Switcher.
You've got 2 major AMP configureiaont.....'D' and 'A/B'......
For now? I'll exclude 'A' amps, but this applies to them, too.....
You can have ANY combination. Swither with 'D'......very common these days.
OR you can have Linear with 'D'. Buy an NC400 modules and bulld your own PS.
But you can also have an A/B amp with eithr. EMO went with a switcher and A/B.
I've never seen one, but you could also have a pure 'A' amp with a switcher. Come to think of it? I have seen one.
The ACA sold as a kit comes with a wall-wart PS. The Amp Camp Amp is a wonderful kit and is single ended 'A'......
Rail switching, like 'G' and 'H' power supplies or even an approach like the high regulation Switcher EMO uses are
moot points when just looking at the major options.......
I also wonder IF a highly regulated PS sacrifices 'dynamic' power for a good, continuous rating.....
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Post by Boomzilla on Aug 16, 2022 0:08:09 GMT -5
Honestly, power amplifiers are getting SO good today (at least for normal listening levels) that I just look for watts per $.
There are some exceptions. “Pro” power amps with built-in DSP I generally avoid. But right now, I own Class-D, Class-AB, and tube amps, ALL of which sound amazing!
I’ve even bought modest AVRs at yard sales that (at normal volumes and normal impedance speakers) sound excellent.
It’s a good time to be an audiophile!
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Post by leonski on Aug 16, 2022 0:54:09 GMT -5
Sure......a 'D' amp with a claimed 250 which is actualy 100, is certainly capable of driving a speaker of reasonable sensitivity.
the exception would be if the amp simply couldn't handle the reactance. It happens, even in so-called good amps.
Since no standard load OTHER than a resister is used, the question of ability than becomes moot until YOU test it with
your speakers...while wondering why is just didn't 'make it'....
While the amp in quetson may only pass FTC requirements at some lower than claimed power, it probably WILL produce claimed power and low distortion
even IF only for a short time periods.....'Duty Cycle' is a measure which could be standardized if amp manufacturers decided it was useful....
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Post by Boomzilla on Aug 16, 2022 5:30:24 GMT -5
Nobody listens at 100W outputs.
Virtually nobody listens at 10W outputs.
Normal listening is <1 Watt.
This isn't an excuse for amps that don't meet their specs. They should. And specs should be standardized so we're always comparing apples to apples (including duty cycle).
But until that happens, we've got what we've got.
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Post by leonski on Aug 16, 2022 14:06:43 GMT -5
Yes......But a path forward must be found....
I think that may be the use of a simulated speaker load with known characteristics of impedance and reactance.
the very Least capable amps will be shown for what they are.
I always keep in mind the crest factor. So if you are running 2 watts average......which for my very low sensitivity panels is possible,
you can hit 20 watts on peaks. That would actually be pretty loud, but not outrageous.
Boom, if you read his post a 2nd time, makes a fine arguement for NOT NEEDING extremely powerful amps....The exception might be
what are really (not just what you 'think') difficult speakers. My low sensitivity panels do not qualify in this regard. Most HT speakers
would also not be on that list. I've seen speakers as tested by Stereophile which had huge reactance swings and at one point or another,
a very low impedance, maybe under 3 ohms Coupled with a very high reactance of 45 degrees or higher. This is a stressful situaiton for
most amps...
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