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Testing PKN XD2500 ClassD Amplifier On DUMMY Load.

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DjLeco View Drop Down
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    Posted: 17 January 2013 at 8:55pm

Finally got one ClassD Professional Amplifier, PKN XD2500, for real testing into dummy load.

Those are official pdf specifications:

http://www.pknc.com/XD_series_user_manual.pdf

 
Movies are in Romanian language, but very simple to understand , if watched movies with attention.
 
Dummy load resistors are 1 ohm/1000Watts, each, seried 2 by 2 to have 2x2 ohms/2000Watts dummy load.
 
 
Testing one channel only, with 4 ohms/4000W dummy load, all resistors seried:


http://www.youtube.com/watch?v=gYSUsRi880A

Testing one channel only, with  2 ohms/2000W dummy load:

http://www.youtube.com/watch?v=7tWFikrMxHo

Testing both channels same time loaded each with 2 ohms/2000W dummy load:

http://www.youtube.com/watch?v=2oP47BGp7mg

 
Enjoy it, I left to all of you, calculations of output power, during 4 and 2 ohm/one channel also for both channels 2x2 ohm load.
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 12:50am
It is nice to see the amplifier managing 2-ohm loads even though it is rated 4-ohm minimum. The 2-ohm stability would be useful if a 4-ohm nominal load dips below 4 ohms under various frequency conditions.

Best Regards,
Elliot Thompson
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MarjanM Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 1:18am
Nice work there. So the amp is going to protect mode at 30Hz when pushed at 2ohm per channel. Good to see how the protection works. Hard to kill that amp isnt it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TENSiON Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 2:12am
I'm only going to say that an ideal bass amp rated to drive 4Ω speakers should also handle driving ~2,66Ω dummy loads without much sweat, as that will be closer to the real impedance of 2 parallely wired 8Ω speakers at certain frequencies..

Seems like the PKN is doing quite well in that regard, considering its ratings.

Seeing it being able to provide 800W continuous (just ~50W short of the 4
Ω performance) with both channels driven into 2Ω loads (although on the verge of thermaling) is quite pleasing. It is only rated for stable operation at 4Ω (or greater), after all..

Nice display of the over-current and temp-protect in action Thumbs Up

PS: Suggestion for next time, also try 2.66
Ω/both channels driven + maybe longer stress tests to allow it reaching thermal equilibrium Smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 9:11am
Originally posted by Elliot Thompson Elliot Thompson wrote:

It is nice to see the amplifier managing 2-ohm loads even though it is rated 4-ohm minimum. The 2-ohm stability would be useful if a 4-ohm nominal load dips below 4 ohms under various frequency conditions.

Best Regards,
 
The amp is made for 2 ohm operation, but with some restrictions:
 
 
 
For TENSiON, those was only tests made, no further ones, because that amp is not mine.
 
What do you (all) have to say, about slew rate at 10 and 20 Khz, also real comportament during squarewave, at 10Khz and 20 Khz, wich looks very different from original squarewave, means, playing 20Khz squarewave, at output signal becomes sinewave instead squarewave?
 


Edited by DjLeco - 18 January 2013 at 9:13am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 2:56pm


Originally posted by DjLeco DjLeco wrote:

Originally posted by Elliot Thompson Elliot Thompson wrote:

It is nice to see the amplifier managing 2-ohm loads even though it is rated 4-ohm minimum. The 2-ohm stability would be useful if a 4-ohm nominal load dips below 4 ohms under various frequency conditions.

Best Regards,



 

The amp is made for 2 ohm operation, but with some restrictions:

 

 


 




Because PKN never stated how much wattage the amplifier would deliver in a 2-ohm load, in addition to informing the user that there may be a chance the amplifier will activate it’s thermal protection @ 2 ohms, that is PKN’s disclaimer. Some manufactures will offer a wattage rating @ 2 ohms and, state such wattage is only for a short period before the protection circuitry comes into play.

The amplifier is rated at 8-ohm and 4-ohm load using burst signals, which appears to be 1.3 milliseconds. Your test is more traditional using a continuous method for a minute or so. The PKN XD 2500 may indeed meet or exceed its advertised wattage ratings if the test was done using a sine wave burst.

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What do you (all) have to say, about slew rate at 10 and 20 Khz, also real comportament during squarewave, at 10Khz and 20 Khz, wich looks very different from original squarewave, means, playing 20Khz squarewave, at output signal becomes sinewave instead squarewave?



The irregularity of the sine wave @ 10 kHz may be due to the limiter activating which, the LED is not indicator is not fast enough to inform you that limiting is taking place. It may also be the latency is not long enough based on the initial sample rate the PKN XD 2500 uses. The above is more of a guess for, I don’t have any digital amplifiers.

Peter from PKN will be able to tell us why such a curvature exists @ 10 kHz.   



Best Regards,

Edited by Elliot Thompson - 18 January 2013 at 3:00pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote U.Viktor Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 4:19pm
Strange. This XD2500 in the videos probably a very old one, it does not have that multilayer circuit boards what my XD amps  have. It is not a music signal but continuous powers look amazing. Do not you make tests with burst signal?

*Have you ever seen what look the 10/20KHz square signal provided by your best CD player? :-D  :-D  :-D


Edited by U.Viktor - 18 January 2013 at 4:22pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2013 at 5:34pm
The freq above 8-10Khz, are modified (I think), by the inductance used in output filter, used, at every classD amplifier, not by the limmiter.

I tried also at low levels, same acting.


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