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Review and Measurements of Crown XLS 1502 Amp

Mr. Malbolgia

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It's not a max consumption spec nor a power supply spec....you need to know what the basis of the consumption spec for it to be meaningful.
I suppose then, I need to know what the spec is. Can you fill me in?

I would like to see more information from Crown in their manuals, they’re pretty weak these days, and false power inflation is a huge problem throughout the industry.

For instance, my father has a pair of EV speaker for gigging that claim 1000 watts. They have a 0.8 amp fuse.
 

sergeauckland

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Does that mean that this power supply is able to pull more juice from the wall than what it is labeled for? Do you know how I could find out the amperage rating at full draw?

I have quite a bit of audio equipment, and the only stuff I have that actually seems to be pulling what it claims to be from the wall is an Onkyo TX-SR876 that actually tells me in the literature how much power it can pull in (9.8 amps) and my subs, which also have the same level of detail. everything else seems to dance around the real numbers.

I mean, nothing in pro audio seems to be spec’d the way it was twenty years ago either. I checked out some old Crown manuals, and they have every number laid out, with no inflation.

Again, looking to learn from this community. These reviews seem to be pretty clinical, and I don’t understand some of it, but power claims have been getting crazier for years.
A class B amplifier has a theoretical maximum efficiency of 78%, in practice, this is more like 60% to provide for the losses in the mains transformer, any output bias current and running the rest of the amplifier circuit. So, if the amp can provide 100 watts per channel, it will draw some 280 watts from the mains when operating at full power on a test tone. The mains transformer and power supply have to be rated for the full 280 watts, but when operating 'normally' on speech or music, it will typically draw only perhaps 40-50 watts from the mains, often much less, so the rating plate on the amplifier stating its power consumption will indicate a much lower figure than the maximum.

Class A amplifiers are only 50% efficient at best, practically somewhere between 20 & 40%,, whilst Class D amplifiers can be some 90%+ efficient, but with the exception of a class A amplifier which draws a constant amount from the mains regardless of how much audio power it's putting out, all other classes draw much less on music than the maximum continuous power.

S
 

Mr. Malbolgia

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A class B amplifier has a theoretical maximum efficiency of 78%, in practice, this is more like 60% to provide for the losses in the mains transformer, any output bias current and running the rest of the amplifier circuit. So, if the amp can provide 100 watts per channel, it will draw some 280 watts from the mains when operating at full power on a test tone. The mains transformer and power supply have to be rated for the full 280 watts, but when operating 'normally' on speech or music, it will typically draw only perhaps 40-50 watts from the mains, often much less, so the rating plate on the amplifier stating its power consumption will indicate a much lower figure than the maximum.

Class A amplifiers are only 50% efficient at best, practically somewhere between 20 & 40%,, whilst Class D amplifiers can be some 90%+ efficient, but with the exception of a class A amplifier which draws a constant amount from the mains regardless of how much audio power it's putting out, all other classes draw much less on music than the maximum continuous power.

S
Excellent, thank you.
 

Chrispy

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Fantastic! Thank you for that. I won’t pretend to understand what the hell I just browsed, but I learned enough to see where I was wrong about the power draw for this unit.

This will give me some reading material for a while, lol!

That undefined (but likely mandated in some place it will be sold) power consumption spec causes a lot of confusion and poor assumptions.
 

snickers

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So short answer is: PA and "Hifi" don't have the same way of what this numbers will say.
In the PA area it's common to write not the max. powersupply capability, but instead of that the value for 1/8 of the max. power draw.
That's what Crown has done here. The 250 Watt are 1/8 of the max. power draining capability of the internel PSU.

But in the normal Home-Hifi market that case is not a use-case, so there is nearly always written the max. power draining capability.
 

sergeauckland

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So short answer is: PA and "Hifi" don't have the same way of what this numbers will say.
In the PA area it's common to write not the max. powersupply capability, but instead of that the value for 1/8 of the max. power draw.
That's what Crown has done here. The 250 Watt are 1/8 of the max. power draining capability of the internel PSU.

But in the normal Home-Hifi market that case is not a use-case, so there is nearly always written the max. power draining capability.
That makes complete sense, as in a PA situation, there may be a rack of 5-10+ amps, all having to be powered off one outlet, so knowing how to rate the outlet, its protective breaker and its cable matters. Using the maximum power rating would result in huge overprovision.

At home, I have volts and amps metering on my hifi rack, and my three power amp, EQ and XO draw 0.5 amps at idle, and still only draw 0.5 amps at normal listening levels. I need to wind things up REALLY LOUD to get the current up to 0.7-0.8 amps whereas on a maximum continuous power rating, current draw would be some 4 amps. Of course it's the LF power amp that carries most of the output, the HF amp,in particular has very little to do, even playing loud, but this illustrates the principle.

S
 

Mr. Malbolgia

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It looks like I came to the right place. I love this hobby, but the more I learn, the less I know. It's just like getting old, only fun. :D

I have spent the majority of my time over the last 3 or 4 years learning about how to squeeze the absolute last drop out of the components I can afford, but sometimes I run up against it. Gain structures, DSP's, power claims, what is audible (to me), why do I hate Audyssey so much, etc, etc. I find that sometimes it is difficult to separate the wheat from the chaff, so to speak.o_O

I essentially buy the best I can afford used, and then tweak the hell out of it. It's great, drives my family nuts.

Thanks again for the answers.
 

rwortman

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Forgive me for asking, but how are these wattage numbers possible? I have the Crown XLS 1502, and the power supply states 250W consumption. How is that they are measuring at 271 per channel continuous?

Can someone walk me through how this (or any amp) can output more than it's power supply provides?

I see these ratings everywhere, and it seems like it's a bit of snake oil.

I answered this question with actual data from Crown earlier in this thread. https://www.audiosciencereview.com/...f-crown-xls-1502-amp.6062/page-13#post-212139

As others have alluded to. Audio professionals have to figure out power requirements when they set up a show. Using ratings for continuous sine waves at full power is useless and would result in asking for 5x or more power than is needed to run the show.
 

diablo900t

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In real world audio quality terms, what does the ADC/DAC conversion and limitation to 24khz mean?
 

kevon27

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How much power does this amp do at 8 ohms? Real power rating, not marketing power rating.
 

rwortman

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How much power does this amp do at 8 ohms? Real power rating, not marketing power rating.

300. It is a real power rating. Crown is an established pro audio company. They don't lie about their power ratings. The spec says 300wpc at 1khz with less than .5% THD. The 4 ohm rating is 525. Amir's test graph, he hit that .5% mark into 4 ohms at a bit under 500. Hard to see exactly where as the graph lacks resolution. I would say that's within the limits of measurement error and production variation. It's not really possible to take his power measurement at .008% THD into 4 ohms and come up with an 8 ohm number. Your question is missing important parameters. How much power at what distortion at what frequency? Full spectrum at under .01%, less than 300, 200 maybe? It's immaterial. If you connect this amp to a pair of 8 ohm speakers and crank it up to 300 watts with a continuous test tone you will not only not hear the distortion, you won't hear anything else for a couple of days until the ringing stops. This amp has gobs of clean power to drive just about any speaker. It's cheap because pro amps are mass produced and they don't spend thousands on fancy casework. Audiophiles don't want to believe it can sound good. OK, spend more. For me, if this thing ever blows up I will be buying another one or whatever Crown replaces it with.
 

Willem

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Pro Audio power amps are often a real bargain. Some time ago I bought a now sadly discontinued 2x250 watt rms into 8 Ohm Yamaha P2500s for my son for 300 euro. It sounds absolutely fine, and is well made. Its bigger 2x350 watt sibling was measured here: https://www.homecinema-fr.com/forum...mpli-yamaha-p3500s-mise-a-jour-t30056383.html Nothing to be ashamed of. There were also 2x500 and 2x700 watt versions. In domestic use the fans never come on.
 

snickers

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Has anybody experience with hiss on this amp with high sensitivity speakers like 98db?
 

Willem

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Neither my son nor I use high sensitivity speakers ( we do not need to with this much power) but the measurements do not suggest a problem.
 

rwortman

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If you have 98db sensitive speakers, you don't need this much power. Some people have reported an audible noise when close to the speaker.
 

Panelhead

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Has anybody experience with hiss on this amp with high sensitivity speakers like 98db?
I have 101.5dB speakers by Measurement. Will hook up later this week to see how this works. Purchased a 1500 and 2000 to drive some 86 dB efficient speakers.
One thing I learned was use the balanced inputs and Speakon outputs to get the best from it. And open the attenuator. All the way. No grit or hum then.
 
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