Crown XLS1002 Pro Amplifier Review

[PeteL]

In this case, it's a very affordable amp with performance matching the price, but gets me thinking, is digitizing the input such a bad thing in amplification? I know that Class D amps are not "digital" and I'm not expert in class d design, except understanding the Basic concept. But for exemple NCORE designs already uses adcs in their feedback circuits as comparators. ADCs and DAC are so good now it should be transparent, with the added benefit of DSP, still it still stick in the mind of the audiophiles that adding convertion in the chain is a bad thing. Again, in this case I don't fully know what I'm talking about, but altough PWM is not digital convertion, it does share common grounds. Seems to me that digitizing the inputs could potentially lead to simpler, cheaper, good performing class D designs but it's still not very common. Wondering if we will see more and more, Just thinking out loud, don't take this as gospel, I'm sure there are pitfalls to this and I'm sure if I was gonna go and study in dept class D design, maybe what I'm suggesting here doesn't even make sense.

 

[tomtoo]

In this case, it's a very affordable amp with performance matching the price, but gets me thinking, is digitizing the input such a bad thing in amplification? I know that Class D amps are not "digital" and I'm not expert in class d design, except understanding the Basic concept. But for exemple NCORE designs already uses adcs in their feedback circuits as comparators. ADCs and DAC are so good now it should be transparent, with the added benefit of DSP, still it still stick in the mind of the audiophiles that adding convertion in the chain is a bad thing. Again, in this case I don't fully know what I'm talking about, but altough PWM is not digital convertion, it does share common grounds. Seems to me that digitizing the inputs could potentially lead to simpler, cheaper, good performing class D designs but it's still not very common. Wondering if we will see more and more, Just thinking out loud, don't take this as gospel, I'm sure there are pitfalls to this and I'm sure if I was gonna go and study in dept class D design, maybe what I'm suggesting here doesn't even make sense.

Just dont take so serious, what some audiophiles think.
There are some chemistry haters that get crazy if you tell them you add some natriumchloride to the food.

 

[spacevector]

Can the AP measure input-to-output delay?

With products like this one which offer DSP capabilities of EQ/XO/etc, the processing may add some delay.

For home theater use, it could have implications for time alignement, lip syncing, etc.

 

[MadMan]

My take on these Crown amps is that the most value is in the DSP functionality, combined with the power for the price. You can get similar power/price with some easy to DIY Icepower stuff, with better performance for strictly amplification.

Given that a lot of the value is in the DSP, it would be really nice to see some of that functionality tested, to see how it might affect performance.

 

[JeffGB]

Comparing the XLS 1002 and the XLS 1502, at first the 1002 looks shaggier, with lots of grass, but actually the noise floor is substantially lower, the spike at 100 Hz is -102 v. -90, third harmonic is -92 v. -78, and the "grass" is -83 v. -73.

Am I misinterpreting this?
View attachment 84755View attachment 84756

I believe Amir didn't have his setup calibrated properly. He later posted the corrected graph https://www.audiosciencereview.com/...easurements-of-crown-xls-1502-amp.6062/page-2

 

[QMuse]

The job last night after helping my wife can more tomatoes was to dehydrate these beauties:

View attachment 84706

They are called "blush" tomatoes and were invented in San Francisco in 2011! They are oval with the most beautiful coloration as if they are peaches. Once ripe, they have an incredible sweet and slightly sour taste. Once dried, they become like slightly sour and sweet candy. The rains are attacking them right now aiming to kill what is left of the plants but I picked another 10 pounds or so today.

You came here to learn about audio but you are also learning about gardening and preserving food as well. Surely that deservers a raise for me in the form of additional donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Actually these are called "pomodori secchi" (dry tomatos). This is a traditional way of preparing tomatos originating from southern Italy (Sicily, city of Pachino in particular), so hard to say when they were "invented", but it's certainly waaay before 2011, in fact many centuries before that. Originally they were dried on the sun but today of course all kind of electric owens are used more often. Before drying they should be sprinkled with salt. After drying they can be preserved in olive oil for quite a long time. Usually a mix of flavors prepared with garlic, oregano, basil, fresh chilli and capers is added to the oil.

 

[MediumRare]

I believe Amir didn't have his setup calibrated properly. He later posted the corrected graph https://www.audiosciencereview.com/...easurements-of-crown-xls-1502-amp.6062/page-2

Thanks, that changed the analysis! Updated my earlier post.

 

[Panelhead]

I think spending the money for a XLS-1502 or higher is well justified. The DriveCore circuit is improved. This is how they measure a little better.
From listening, this was tested in an optimal scenario. They are better using Speakon and balanced inputs. Less hum with balanced in.
The 48k sampling for DSP is a big limiting factor. But listening does reveal this issue.
I purchased my XLS-1500 and XLS-2000 after the “02” updated units were released. Think it was 179.00 and 239.00. Missed out on the 149.00 XLS-1500.
Assume there will be another update.
Also a question on the power supply. Someone more knowledgeable than me on these told me it is a linear supply and not a switching. They felt the chokes will ring and resonate. Poor design.
When I looked at them they looked like switching supplies. But years later, they look like resonant mode supplies.
Are they normal switching supplies?

 

[MediumRare]

I think spending the money for a XLS-1502 or higher is well justified. The DriveCore circuit is improved. This is how they measure a little better.
From listening, this was tested in an optimal scenario. They are better using Speakon and balanced inputs. Less hum with balanced in.
The 48k sampling for DSP is a big limiting factor. But listening does reveal this issue.
I purchased my XLS-1500 and XLS-2000 after the “02” updated units were released. Think it was 179.00 and 239.00. Missed out on the 149.00 XLS-1500.
Assume there will be another update.
Also a question on the power supply. Someone more knowledgeable than me on these told me it is a linear supply and not a switching. They felt the chokes will ring and resonate. Poor design.
When I looked at them they looked like switching supplies. But years later, they look like resonant mode supplies.
Are they normal switching supplies?

Are you saying there's a difference between the 1002 and 1502 other than the power output level? Cost-wise is $60-$100 upgrade.

 

[JeffGB]

Are you saying there's a difference between the 1002 and 1502 other than the power output level? Cost-wise is $60-$100 upgrade.

The 1002 uses the AD/DA built into the LSI chip they had designed for their class D amps by TI. The 1502 uses a higher performance outboard converter the CS4272 per the Crown service manual. The CS4272 gives the 1502 and higher models 3-4db better noise level.

 

[MediumRare]

The 1002 uses the AD/DA built into the LSI chip they had designed for their class D amps by TI. The 1502 uses a higher performance outboard converter the CS4272 per the Crown service manual. The CS4272 gives the 1502 and higher models 3-4db better noise level.

Where in Amir's measurements would we see that difference?

 

[JeffGB]

Where in Amir's measurements would we see that difference?

I'm not sure if the difference that Amir measured really shows the level of noise at idle but I think that is where the audible improvement is. There have been other reviewers that returned the 1002 due to noise and replaced with 1502 or higher and were satisfied. I have a 1500 but have not heard a 1000/1002 so I don't know first-hand.

 

[mhardy6647]

Member wanted to buy it through us but the margin on it was no more than a cup of coffee (relative to online sites) so I suggested he buy it elsewhere which he did.

Yeah, but where you are, the price of a cuppa coffee would feed us for a day here in northern New England!

Now, as to bears and groundhogs -- those we've got. Deerses, too.

DSC_1570 by Mark Hardy, on Flickr
DSC_3707 by Mark Hardy, on Flickr
DSC_0174 (2) by Mark Hardy, on Flickr

On topic, I keep getting tempted to acquire one of these Crowns -- mostly to use for subwoofage, but I would be curious (academically, that is) to try one full-range as a hifi amplifier, too.

 

[cistercian]

Yeah, but where you are, the price of a cuppa coffee would feed us for a day here in northern New England!

Now, as to bears and groundhogs -- those we've got. Deerses, too.

DSC_1570 by Mark Hardy, on Flickr
DSC_3707 by Mark Hardy, on Flickr
DSC_0174 (2) by Mark Hardy, on Flickr

On topic, I keep getting tempted to acquire one of these Crowns -- mostly to use for subwoofage, but I would be curious (academically, that is) to try one full-range as a hifi amplifier, too.

Try one. I remember when I ordered my first one, the 1002. I was amazed a PA amp could be so competent and sound so nice.
Listening to my 2502 into my SRX835's right now...most impressive even at lower volume. I am still surprised how well the combo
works...it totally undermines the whole mega bucks only sound good paradigm. I am listening at the level where the signal present LEDS
are almost full on.
There is clip, 10db from clip, 20db from clip, and signal present. 20db from clip is live concert level in my small mancave.
10db from clip reboots the computer and makes the LED mancave light dim to bass hits. Ancient wiring 14ga just is not stout
enough for the 2502.
I need to run 12ga. But the combination of laziness and sure structural damage prevents me.

Make no mistake...not audiophile. But more than enough for the majority of users. EDM is particularly comical.
And...so much better than my 70's era gear it is incredible! Detailed with excellent bass power the combo is delicious.
Too inexpensive not to try in my opinion.

PS. I have had bears in my driveway and peering in the windows too! No deer in my yard. But a large mountain lion zoomed through
some years ago...that was interesting to say the least. Officially they don't exist here. Many photos prove otherwise.
Asheville, NC

 

[Jdunk54nl]

I really think this post here sums up these crown amps use. sure there are better amps, but do you have good enough speakers to realize those gains?

https://www.audiosciencereview.com/...n-in-electronics-meaningful.15775/post-505085

Uncorrelated it should RSS -- root-sum-square -- so calculate each distortion term, square it, add all the squared terms, take the square root, and calculate the new distortion. So if the speakers are at -60 dBc and amp at -80 dBc then the distortion is (10^-60*2/20 + 10^-80*2/20) = 0.00000101 (using voltages) and converting back to dBc (20*log) the result is -59.96 dBc -- about 0.04 dB reduction in performance from the amp. A DAC at -130 dBc is in the mud...

 

[restorer-john]

I was unhappy to see distortion shoot up at higher frequencies

Is that the "good" channel or the "bad" channel or both?

Also, with only a 45KHz bandwidth, the 20KHz (red) plot (only the 2nd harmonic will show and to a lesser extent the 15Khz) is not representative.

 

[restorer-john]

Now don't laugh but I could not figure out how to pull out the safety plugs they put in the darn binding posts!

A tapered wood/plasterboard screw is good for that. Just twist it carefully into the plastic plug until it grabs and then pull it straight out. No damage to either piece and you can push it back in afterwards.

 

[restorer-john]

It is strange but moles love them! The dig around them every spring.

So you've got moles, deer and groundhogs. We've got possums, wallabies, bandicoots and cockatoos. We've just given up trying to grow anything. Even herbs. You go out one day and you have a nice big basil plant. Next morning, nothing but dirt in the pot. And that was 30ft above the forest floor on our back deck.

 

[Rja4000]

How does it perform in bridged mode ?
Any idea ?

 

[Francis Vaughan]

But for exemple NCORE designs already uses adcs in their feedback circuits as comparators. ADCs and DAC are so good now it should be transparent, with the added benefit of DSP, still it still stick in the mind of the audiophiles that adding convertion in the chain is a bad thing. Again, in this case I don't fully know what I'm talking about, but altough PWM is not digital convertion, it does share common grounds. Seems to me that digitizing the inputs could potentially lead to simpler, cheaper, good performing class D designs but it's still not very common.

The Ncore design is fundamentally a self oscillating PWM amplifer, which makes it intrinsically difficult to see how it could work with a fixed period sampled digital input. Not impossible, you can, in principle, shift any part of the topology into the digital domain, but within the bandwidths and computation limits, pretty difficult. I'm not sure how they might use an ADC in the comparator except that in some sense a comparator is a 1 bit ADC, although the comparator in the Ncore amplifier is a zero crossing detector, which is not quite the same thing as a simple level comparator. There are other places in the amplifier where some digital control is useful, most certainly in the protection circuitry, and maybe control of the forward filter could be effected, which would be central to the Ncore design.
The basic Ncore patent is well written and worth a read.

Combined DAC/PWM devices certainly exist. Of note for ASR denizens is the beloved JBL LSR 30x family, that uses the STA 305B for the entire digital chain, from digital in, DSP, and power amp. Not exactly a high end chip, but the end result in the loudspeaker does not seem to generate complaints about fidelity. There is no definable DAC in this chip that is separate to the power amplifier, and one might indeed characterise it as a power DAC. But an Ncore it certainly isn't.

The Ncore plate amplifiers are available with DSP, they include a conventional DAC feeding an analog signal to the amplifiers.