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Review and Measurements of Crown XLS 1502 Amp

amirm

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#1
This is a review and detailed measurements of the Crown XLS 1502 "PA" Power Amplifier. It is on a kind loan from a member who bought it new and drop shipped it to me. It retails for USD $349 including free Prime shipping from Amazon. At that price, it seems like an incredible value.

I have to say, while the unit looks industrial/military, it does not at all feel cheap. As expected it comes in 19 inch rack mount configuration but very shallow:

Crown XLS 1502 Amplifier Review.jpg

Not only do you get a high power amplifier with front graphical display and such, but also a built-in DSP. It is not a fancy subsystem but allows you to dial in crossovers and such which is very handy in live sound. At may company (Madrona Digital) we use a ton of Crown amps not for hifi applications but for music distribution in the home. The built-in DSPs come in handy for limiting the frequency range, max output, etc..

Unlike home units, the XLS 1502 has a built-in fan with tons of holes for ventilation as you see. Fortunately it is temperature controlled and barely came on during my nearly 50 watt soak time. And when it came on, it was very quiet.

Here are the guts of the unit (click on the image for larger size):

Crown XLS 1502 Teardown Amplifier Main PCB.jpg


Man, is this clean! Look at the beefy mains chokes to keep noise at bay. The power supply is integrated on the same board as the power amplifier so you can't swap one to fix the unit although at these prices, getting a new unit is more economical anyway. The fan is placed not only in front of the heatsinks for the power transistors but also the output filter inductors which is nice as far as keeping them cool too.

I noticed that the output stage is depopulated. Seems then that the step up model just has a few more parts in it and that is that:

Crown XLS 1502 Teardown Amplifier PCB Reduced.jpg

There are tons of connectors in the back which I let you read about elsewhere. Overall, this is jaw droppingly nice unit and unbelievable at the price that is being charged.

I did a lot of searching and was surprised that there were no measurements of these units. A lot of empty reviews, yes. But no measurements. So you get to have an exclusive set of data in this review! :) So let's get into that.

Measurements
I started by cooking the unit for a while at 48 watts with kind permission from its owner:
Crown XLS 1502 Amplifier Warm Up Measurements.png


Unlike some other amps, bringing the unit up to temp ever so slightly worsens performance. There are also some interesting thermal effects from time to time represented by the spikes. Anyone who thinks they can predict what thousands of components do as they warm up should get into predicting the weather on tuesday next week, 10 years from now! :)

Anyway, let's look at our dashboard at 5 watts of output:

Crown XLS 1502 Amplifier  Measurements.png


Sorry I did not set the reference in the FFT. But the news is there in the SINAD (signal over distortion and noise) of just 75 dB. We have seen worse but also much, much better. Gain is about 30 dB by the way.

Signal to noise ratio is decent but again, nothing high-end about it:

Crown XLS 1502 Amplifier SNR Measurements.png


Let's look at power versus distortion+noise:
Crown XLS 1502 Amplifier Power Into 4 ohm Measurements.png


So we see that the Crown XLS 1502 easily outperforms the no-name Chinese class D amp we recently tested (IRAUD350). It has a well behaved response with sloping down curve and then onset of clipping. Power was around 336 watts @ 0.008% distortion. I say "around" as there are not enough points in these measurements to find the exact onset of clipping. The number is therefore a bit understated. Crown specs the unit at 525 watts though at 4 ohm and we are not going to get there without a lot of distortion.

The hypex Hyped DIY Nc400 amplifier far outperforms the XLS 1502. It has far lower noise and distortion although not as much power before clipping. It costs nearly four times as much though.

I thought I do a comparison against the Behringer A500. The A500 feels a lot more cheaply made but is also priced at $199:
Crown XLS 1502 Amplifier Power Into 4 ohm compared to Behringer A500 Measurements.png


We see that the Crown XLS 1502 is better in every regard with lower noise and much more usable power before clipping.

I thought the continuous power would be a walk in the part for the XLS 1502 but did present a surprise:

Crown XLS 1502 Amplifier Continuous Power Test Measurement.png


The red "thermal" light came on the front panel but instead of shutting down, the power was reduced a bit. "The show must go on" seems to be the rule here and nice to see instead of full shutdown we saw with Hypex Nc400. As you see, I let the unit keep going and it went to 8+ minute maintaining that status.

Frequency response was surprising but easily explainable:
Crown XLS 1502 Amplifier Frequency Response Measurements.png


We have a "brickwall" style filter which indicates our analog input is digitized first through an ADC running at 48 kHz sampling, processed through DSP (or not), and then converted back to analog before amplification. Both the ADC and DAC therefore sharply limit the bandwidth to 48 kHz. I was surprised to see some roll off at 20 Hz too.

Wideband FFT (without AES filter) as usual shows a lot of activity in higher frequencies:
Crown XLS 1502 Amplifier broadband FFT  Measurements.png


The first peak is very nicely truncated at a little less than 100 kHz to pass emissions standards (by 60 dB). Crown class I devices interleave the output stages which would explain the energy spread over four quadrants at multiples of that ~100 kHz pulses. Since the XLS 1502 has passed emissions standards I would not worry too much about them.

Conclusions
It is hard to fathom that a properly engineered and produced mainstream brand amplifier with so much power can be sold for so little money. This is a robust but bargain amplifier designed for heavy punishment in live sound. Can it be used for hi-fi use? Sure but it will severely limit both the resolution and potentially bandwidth of upstream sources. Its best use would be as a subwoofer amplifier. If you need an all in one unit, Hypex NC400/NC500 designs are so far my choice among amplifiers tested.

-------------
As always, questions, comments, recommendations, etc. are welcome.

If you like this review, or even if you don't but wish for me to escape the rain in Seattle and go somewhere sunny, please consider donating using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
 

andreasmaaan

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#2
Pretty solid performance for the price.

Any idea why the input goes through an internal AD-DA conversion?
 

RayDunzl

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#3

svart-hvitt

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#4
This is a review and detailed measurements of the Crown XLS 1502 "PA" Power Amplifier. It is on a kind loan from a member who bought it new and drop shipped it to me. It retails for USD $349 including free Prime shipping from Amazon. At that price, it seems like an incredible value.​

I have to say, while the unit looks industrial/military, it does not at all feel cheap. As expected it comes in 19 inch rack mount configuration but very shallow:


Not only do you get a high power amplifier with front graphical display and such, but also a built-in DSP. It is not a fancy subsystem but allows you to dial in crossovers and such which is very handy in live sound. At may company (Madrona Digital) we use a ton of Crown amps not for hifi applications but for music distribution in the home. The built-in DSPs come in handy for limiting the frequency range, max output, etc..

Unlike home units, the XLS 1502 has a built-in fan with tons of holes for ventilation as you see. Fortunately it is temperature controlled and barely came on during my nearly 50 watt soak time. And when it came on, it was very quiet.

Here are the guts of the unit (click on the image for larger size):

View attachment 19982

Man, is this clean! Look at the beefy mains chokes to keep noise at bay. The power supply is integrated on the same board as the power amplifier so you can't swap one to fix the unit although at these prices, getting a new unit is more economical anyway. The fan is placed not only in front of the heatsinks for the power transistors but also the output filter inductors which is nice as far as keeping them cool too.

I noticed that the output stage is depopulated. Seems then that the step up model just has a few more parts in it and that is that:


There are tons of connectors in the back which I let you read about elsewhere. Overall, this is jaw droppingly nice unit and unbelievable at the price that is being charged.

I did a lot of searching and was surprised that there were no measurements of these units. A lot of empty reviews, yes. But no measurements. So you get to have an exclusive set of data in this review! :) So let's get into that.

Measurements
I started by cooking the unit for a while at 48 watts with kind permission from its owner:
View attachment 19984

Unlike some other amps, bringing the unit up to temp ever so slightly worsens performance. There are also some interesting thermal effects from time to time represented by the spikes. Anyone who thinks they can predict what thousands of components do as they warm up should get into predicting the weather on tuesday next week, 10 years from now! :)

Anyway, let's look at our dashboard at 5 watts of output:

View attachment 19985

Sorry I did not set the reference in the FFT. But the news is there in the SINAD (signal over distortion and noise) of just 75 dB. We have seen worse but also much, much better. Gain is about 30 dB by the way.

Signal to noise ratio is decent but again, nothing high-end about it:

View attachment 19986

Let's look at power versus distortion+noise:
View attachment 19987

So we see that the Crown XLS 1502 easily outperforms the no-name Chinese class D amp we recently tested (IRAUD350). It has a well behaved response with sloping down curve and then onset of clipping. Power was around 336 watts @ 0.008% distortion. I say "around" as there are not enough points in these measurements to find the exact onset of clipping. The number is therefore a bit understated. Crown specs the unit at 525 watts though at 4 ohm and we are not going to get there without a lot of distortion.

The hypex Hyped DIY Nc400 amplifier far outperforms the XLS 1502. It has far lower noise and distortion although not as much power before clipping. It costs nearly four times as much though.

I thought I do a comparison against the Behringer A500. The A500 feels a lot more cheaply made but is also priced at $199:
View attachment 19988

We see that the Crown XLS 1502 is better in every regard with lower noise and much more usable power before clipping.

I thought the continuous power would be a walk in the part for the XLS 1502 but did present a surprise:

View attachment 19989

The red "thermal" light came on the front panel but instead of shutting down, the power was reduced a bit. "The show must go on" seems to be the rule here and nice to see instead of full shutdown we saw with Hypex Nc400. As you see, I let the unit keep going and it went to 8+ minute maintaining that status.

Frequency response was surprising but easily explainable:
View attachment 19990

We have a "brickwall" style filter which indicates our analog input is digitized first through an ADC running at 48 kHz sampling, processed through DSP (or not), and then converted back to analog before amplification. Both the ADC and DAC therefore sharply limit the bandwidth to 48 kHz. I was surprised to see some roll off at 20 Hz too.

Wideband FFT (without AES filter) as usual shows a lot of activity in higher frequencies:
View attachment 19991

The first peak is very nicely truncated at a little less than 100 kHz to pass emissions standards (by 60 dB). Crown class I devices interleave the output stages which would explain the energy spread over four quadrants at multiples of that ~100 kHz pulses. Since the XLS 1502 has passed emissions standards I would not worry too much about them.

Conclusions
It is hard to fathom that a properly engineered and produced mainstream brand amplifier with so much power can be sold for so little money. This is a robust but bargain amplifier designed for heavy punishment in live sound. Can it be used for hi-fi use? Sure but it will severely limit both the resolution and potentially bandwidth of upstream sources. Its best use would be as a subwoofer amplifier. If you need an all in one unit, Hypex NC400/NC500 designs are so far my choice among amplifiers tested.

-------------
As always, questions, comments, recommendations, etc. are welcome.

If you like this review, or even if you don't but wish for me to escape the rain in Seattle and go somewhere sunny, please consider donating using:
Patreon: https://www.patreon.com/audiosciencereview), or
upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
Much appreciated review!
 

Jimster480

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#5
Pretty interesting but still not so great performance.

What would you really need that much wattage for?
I have a few sets of speakers and even at 30W things get really friggin loud unless you have a GIGANTIC room.

I have a Heos 7 at my house and it completely fills my large room (half of which has 27FT ceilings and the other half with 10-12ft ceilings) with the volume set to like 25%. At 50% people will have to shout over it and this room is easily 400sq foot, might even be 500 sq foot!
 

tomelex

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#6
I like your pink panther thingy I see on your reviews of gear, and thanks for the review, interesting and hard to find information, cheers Amir!
 

amirm

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#7
Any idea why the input goes through an internal AD-DA conversion?
To perform the DSP function which they assume is common in the PA application. They could have put in an analog bypass but have chosen not to.
 

svart-hvitt

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#8
To perform the DSP function which they assume is common in the PA application. They could have put in an analog bypass but have chosen not to.
If the ADDA conversion (DSP) is higher specified (noise and distortion wise) than the amplifier, is there any downside in going through an extra DSP stage?
 

andreasmaaan

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#9
If the ADDA conversion (DSP) is higher specified (noise and distortion wise) than the amplifier, is there any downside in going through an extra DSP stage?
Assuming the AD-DA's contribution to noise and distortion is negligible and the latency is very low (as it no doubt would be), I can't see any issue.
 

RayDunzl

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#10
What's the maximum power level at which you could run a quick performance scan?
 

amirm

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#11
What's the maximum power at which you could run a quick performance scan?
The Behringer graph is that. You can see nearly 500 watts at 0.5% THD+N.
 

amirm

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#15
Ah, forgot to post the thermal image at continuous near max power level:

Crown XLS 1502 Amplifier Continuous Power Test Thermal Measurement.jpg


The power supply seems to be the hottest since it doesn't get as much airflow as the amplifier.
 
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