Review and Measurements of Crown XLS 1502 Amp

[dlaloum]

I have my xls 1502 at home and it works great (so far no hiss issues, it works just fine)
How should I set the gain regulators at both sides of the screen? I have them at 25% of their total capacity, is that ok_

In a perfect world, you would determine the optimal output from your pre-outs, and then adjust the gain so you get the lowest possible THD+N, while still having full output available...

In the real world, I set it to around 75% and be done with it - I have no hiss.

If you have access to a review of your pre, where the pre-out was measured for SINAD or THD+N at different levels - you will be able to see where the performance is best - and whether you should aim for high gain (turn down the pre) or low gain (turn up the pre)

Also mine is first generation, on the second generation models like yours, you also have an option for consumer vs pro sensitivity (high gain vs low gain) and the gain dial then works on top of that.

 

[TimoJ]

If you have access to a review of your pre, where the pre-out was measured for SINAD or THD+N at different levels - you will be able to see where the performance is best - and whether you should aim for high gain (turn down the pre) or low gain (turn up the pre)

There is also idle noise (noise floor) of the preamp/avp that is rarely (never?) measured but it also should be taken into account when selecting power amp gains.

 

[EJ3]

There is also idle noise (noise floor) of the preamp/avp that is rarely (never?) measured but it also should be taken into account when selecting power amp gains.

I think that it would only matter IF they were audible.

 

[TimoJ]

I think that it would only matter IF they were audible.

Yes, but for example Trinnov needs low gain amps (or amps with gain adjustments or inline attenuators) because of this.

 

[dlaloum]

There is also idle noise (noise floor) of the preamp/avp that is rarely (never?) measured but it also should be taken into account when selecting power amp gains.

Yep - crank the gain too much on the power amp, and you can potentially hear the noise floor .... which IMO is why there are reports of Hiss...

Lots of people make the mistake of running with the Gain at MAX - cos you know ... more power!... and then complain about hiss!

 

[Deleted member 71304]

In a perfect world, you would determine the optimal output from your pre-outs, and then adjust the gain so you get the lowest possible THD+N, while still having full output available...

In the real world, I set it to around 75% and be done with it - I have no hiss.

If you have access to a review of your pre, where the pre-out was measured for SINAD or THD+N at different levels - you will be able to see where the performance is best - and whether you should aim for high gain (turn down the pre) or low gain (turn up the pre)

Also mine is first generation, on the second generation models like yours, you also have an option for consumer vs pro sensitivity (high gain vs low gain) and the gain dial then works on top of that.

Thanks for your response.
In regard to the sensitivity settings, the so called "normal" one is 1.4 V and the "high sensitivity" 0.75 V. I am using the first one because my source (Schiit saga 2) is XLR.
Also there is sth interesting: If the amp is on and the preamp is off then a strong hiss comes out of the speakers. As soon as the preamp is turned on the hiss dissapears. I don't know if this is relevant but am quite curious, if someone happened to know the reason for this.

 

[staticV3]

Also there is sth interesting: If the amp is on and the preamp is off then a strong hiss comes out of the speakers. As soon as the preamp is turned on the hiss dissapears. I don't know if this is relevant but am quite curious, if someone happened to know the reason for this.

Does the hiss disappear when you plug out the preamp?

 

[Deleted member 71304]

Does the hiss disappear when you plug out the preamp?

Yes, it disappears when I plug the preamp out (also when the preamp is on)

 

[staticV3]

Yes, it disappears when I plug the preamp out (also when the preamp is on)

Sounds like a poorly designed preamp. Have you contacted Schiit regarding this issue?

 

[Deleted member 71304]

Sounds like a poorly designed preamp. Have you contacted Schiit regarding this issue?

I just tried doing the same with a different amp (Boxem Hypex NC500x) and it doesn't produce this noise.
Anyway, it's not an issue while hearing music.
Thank you for your response

 

[calvados.boulard]

Yes, it disappears when I plug the preamp out (also when the preamp is on)

Sorry can you please explain what it means to "plug the preamp out"? Do you mean unplug the power cable, or perhaps disconnect all the inputs into the preamp?

 

[Deleted member 71304]

Sorry can you please explain what it means to "plug the preamp out"? Do you mean unplug the power cable, or perhaps disconnect all the inputs into the preamp?

"Plug the preamp out" = unplug the XLR or RCA cables that connect it to the power amp

 

[calvados.boulard]

"Plug the preamp out" = unplug the XLR or RCA cables that connect it to the power amp

Thank you!

 

[JeffGB]

I run an XLS-1500 daily in my system, using a Schiit headphone amp as preamp (Schiit Heresy). I originally tried to use RCA to RCA on the Crown and had nothing but noise problems. It wasn't hum, it was RF interference. I tried everything I could think of and nothing fixed it other than using a full balanced preamp. Recently I built my own RCA to XLR cable, by changing an existing XLR cable from a musical instrument store. It was two conductors plus shield. I removed the preamp end and replaced it with an RCA plug with the + wire connected to the center pin as usual and the negative wire connected to the ground terminal, in addition to the shield being connected to the ground terminal. The XLR end connects the shield to the chassis and the - wire to the -input of the amplifier. The noise is now completely gone, with all RCA devices I connect to the Crown. There are RCA to XLR cables available commercially but many are not wired correctly and won't fix the problem. The two wire cable plus shield is absolutely necessary for it to work properly. I wish I had tried it many months ago!

 

[Deleted member 71304]

I run an XLS-1500 daily in my system, using a Schiit headphone amp as preamp (Schiit Heresy). I originally tried to use RCA to RCA on the Crown and had nothing but noise problems. It wasn't hum, it was RF interference. I tried everything I could think of and nothing fixed it other than using a full balanced preamp. Recently I built my own RCA to XLR cable, by changing an existing XLR cable from a musical instrument store. It was two conductors plus shield. I removed the preamp end and replaced it with an RCA plug with the + wire connected to the center pin as usual and the negative wire connected to the ground terminal, in addition to the shield being connected to the ground terminal. The XLR end connects the shield to the chassis and the - wire to the -input of the amplifier. The noise is now completely gone, with all RCA devices I connect to the Crown. There are RCA to XLR cables available commercially but many are not wired correctly and won't fix the problem. The two wire cable plus shield is absolutely necessary for it to work properly. I wish I had tried it many months ago!

In my case the hiss is not relevant, like stated above it only appears when the Crown is on and the preamp is off.
Once I turn on the preamp there is no hiss and it sounds just great. It is really amazing for 430€ (I have compared it with a Hypex and I cannot hear a difference, not that I have particularly good ears but it is certainly worth a try)

 

[Deleted member 71304]

I run an XLS-1500 daily in my system, using a Schiit headphone amp as preamp (Schiit Heresy). I originally tried to use RCA to RCA on the Crown and had nothing but noise problems. It wasn't hum, it was RF interference. I tried everything I could think of and nothing fixed it other than using a full balanced preamp. Recently I built my own RCA to XLR cable, by changing an existing XLR cable from a musical instrument store. It was two conductors plus shield. I removed the preamp end and replaced it with an RCA plug with the + wire connected to the center pin as usual and the negative wire connected to the ground terminal, in addition to the shield being connected to the ground terminal. The XLR end connects the shield to the chassis and the - wire to the -input of the amplifier. The noise is now completely gone, with all RCA devices I connect to the Crown. There are RCA to XLR cables available commercially but many are not wired correctly and won't fix the problem. The two wire cable plus shield is absolutely necessary for it to work properly. I wish I had tried it many months ago!

Regarding the rca connection, FWIW I have also tried the Crown with an integrated amp working as preamp (it has rca pre-out) and no hiss nor noise was to be heard at all.

 

[Gringoaudio1]

Being pedantic what is referred to in the USA as the English system isn’t. The Imperial system, which was used in the United Kingdom until 1968 is different from the system used in the USA in several ways, a bit like the language and spelling.
For example the “cup” is afaik a purely US measure, not used in the UK, in baking dry units were measured by weight and liquids in pints and ounces, never “cups”, for example.
The Imperial gallon is bigger than a US gallon, 20 fl oz instead of 16.
We officially went to the SI units system in 1968 but a lot of older people still use stones for their weight (nobody would give their weight in pounds) though I have used kg myself for decades.
Farmers mainly still talk acres rather than hectares, speeds are still in mph on road signs and distances in miles (or yards for short distances).
Many older people still use farenheit when checking the weather, I don’t.
The differences are minor, but the measurement system and language used in the USA are not strictly “English”

US/Imperial Pint not Gallon is 16/20. Gallon is 32/40.

 

[EJ3]

US/Imperial Pint not Gallon is 16/20. Gallon is 32/40.

Whitworth, anyone?

Historical misuse​

British Morris and MG engines from 1923 to 1955 were built using metric threads with bolt heads and nuts dimensioned for Whitworth spanners and sockets. In 1919, Morris Motors took over the French Hotchkiss engine works which had moved to Coventry during the First World War. The Hotchkiss machine tools were of metric thread but metric spanners were not readily available in Britain at the time, so fasteners were made with metric thread but Whitworth heads.

Ah, yes, nothing like a bit of confusion!

 

[Rahan]

It would be nice to see the review of the brother XLC 2500. It's basically the same than the XLS 1502 but without any DSP, so without any D/A or A/D conversion. I'm curious to see how much does it remove the XLS limitations.

 

[rvsixer]

It would be nice to see the review of the brother XLC 2500. It's basically the same than the XLS 1502 but without any DSP, so without any D/A or A/D conversion. I'm curious to see how much does it remove the XLS limitations.

Go ahead and send one in then, that's how it works here.