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Old 1st March 2009, 11:33 AM   #1
uuv is offline uuv  Hungary
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Default PKN amplifiers

Dear Sirs,

I have had PKN XD-4000 amps for long time... these amps have relative very high sound quality and its output power level is exciting :_) we have measured almost 2x 2500Watts on 4Ohms load in pulsed mode.
The price is not 2200EUR anyway, i have bought them half of this amount ;-)

u.
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Old 2nd March 2009, 12:18 PM   #2
iand is offline iand  United Kingdom
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Default Re: PKN amplifiers

Quote:
Originally posted by uuv
Dear Sirs,

I have had PKN XD-4000 amps for long time... these amps have relative very high sound quality and its output power level is exciting :_) we have measured almost 2x 2500Watts on 4Ohms load in pulsed mode.
The price is not 2200EUR anyway, i have bought them half of this amount ;-)

u.
I was considering trying out the XD-4000 but can't find any reviews or test results anywhere and am reluctant to risk 1100EU on an unknown...

Do you have more measurements, especially about how long the output can be sustained for before being reduced? (many class-D amps can only output full power for a few seconds, or much less in some cases)

Ian
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Old 2nd March 2009, 02:04 PM   #3
uuv is offline uuv  Hungary
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Default differences

Every amplifiers have different sound characteristics, not only the end stages the construction of power supply is also important.
Some of switching amplifiers "class-D" has feedback NOT from the real audio output, they have feedback before the output filter.
This soulution would work well with resistive load... but the real world speaker is NEVER resisive-like ;-) So the problem is when the feedback is not from the real output the error-amp can not compensate the nonlinearity and fails of output filter.
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Old 2nd March 2009, 05:18 PM   #4
uuv is offline uuv  Hungary
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Default Re: Re: PKN amplifiers

Quote:
Originally posted by iand


I was considering trying out the XD-4000 but can't find any reviews or test results anywhere and am reluctant to risk 1100EU on an unknown...

Do you have more measurements, especially about how long the output can be sustained for before being reduced? (many class-D amps can only output full power for a few seconds, or much less in some cases)

Ian

Dear Ian

We have more fortune since located close to the manufacturer, and saw everything... ;-) So the PKN XD-4000 have 155V peak output voltage for short time. Measured long time average is 2150Watts per channel at resistive 4 OHMs for one minute. I have recorded 25A current draw while the line drops down to 226V. After one minute constant sine 1KHz drive the amp reduces its output power to ~2*1500W. In real world enviroment this would never happen beacuse the speakers have no resistive characterictics and the music signal is not continous sine wave.... I have experienced much much less heat dissipation (temperature of amps) in live system than running on resistive load test.
Anyway i have measurement and pictures of disassembled amps, if you are interested.
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Old 2nd March 2009, 10:18 PM   #5
iand is offline iand  United Kingdom
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Default Re: Re: Re: PKN amplifiers

Quote:
Originally posted by uuv



Dear Ian

We have more fortune since located close to the manufacturer, and saw everything... ;-) So the PKN XD-4000 have 155V peak output voltage for short time. Measured long time average is 2150Watts per channel at resistive 4 OHMs for one minute. I have recorded 25A current draw while the line drops down to 226V. After one minute constant sine 1KHz drive the amp reduces its output power to ~2*1500W. In real world enviroment this would never happen beacuse the speakers have no resistive characterictics and the music signal is not continous sine wave.... I have experienced much much less heat dissipation (temperature of amps) in live system than running on resistive load test.
Anyway i have measurement and pictures of disassembled amps, if you are interested.
Wow, that's pretty impressive -- actually, it's *much* better sustained power than any of the amps from the big switchmode amp manufacturers like Powersoft, QSC, Lab Gruppen (not to mention the cheap Chinese amps like Kobble).

I did wonder if this would be the case given that PKN's background is high-power lab supplies, it's nice to have it confirmed though :-)

Maybe PKN should publicise this aspect of their amp performance more, because it's one of the biggest complaints that many people have about lightweight class-D amps -- especially in some types of music (dubstep or similar) which have very long sustained almost sinewave bass notes. I know there is strong interest in the UK and elsewhere in amps which can deliver this kind of sustained power, but nobody's heard of PKN here.

I'd certainly be interested in seeing any more detailed measurement results and photos that you have -- please use the email address which is like

audio(at)dedics(dot)co(dot)uk

Cheers

Ian
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Old 2nd March 2009, 11:22 PM   #6
TOINO is offline TOINO  Portugal
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I am also interested, please...
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Old 3rd March 2009, 01:49 PM   #7
uuv is offline uuv  Hungary
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Default switching amp inside

Here are some spy pictures of dissassembled amp ;-)
http://picasaweb.google.com/ulusevszky.viktor/Amps#
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Old 3rd March 2009, 03:24 PM   #8
iand is offline iand  United Kingdom
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Default Re: switching amp inside

Quote:
Originally posted by uuv
Here are some spy pictures of dissassembled amp ;-)
http://picasaweb.google.com/ulusevszky.viktor/Amps#
I think the "unknown components" in photo 5 are differential current sense transformers -- the thick single-wire loops carry the output current from the bridge, the fine winding is a step-up which connects to a sense circuit (you can see the connections in photo 4 on the bottom side of the amp PCB).

Interesting to also see the fuse ratings -- 20A on the mains input, 32A on the DC bus (I assume this is around 160V?) from the SMPS PCB to amp PCB, which is about 5kW rating...

The whole amp does look like a high quality design, especially the SMPS which is much more advanced than most other designs (resonant instead of hard-switched, foil-wound transformer and Litz wire inductors or maybe the other way round, 18000uF total output capacitor=230J energy storage at 160V) -- you can really tell that PKN know how to do a good PFC+SMPS, unlike most of the class-D amp manufacturers.

Now if only it was the same price as the nasty Chinese ones...

(yes I know, 1100EUR for >4kW genuine power is a bargain :-)

Ian
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Old 3rd March 2009, 04:18 PM   #9
uuv is offline uuv  Hungary
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Default PKN XD-4000

I have measured the voltage of power supply: 402VDC
The voltage of end-stage is 167VDC in steady-state.
This amp is not sensitive for line changes ( i don't know because of the PFC or not) sometimes we have had very dirty line (~190V instead of ~230V) but the amps working! when the CD players do not :_)

So i am driving 4pcs 18" 1000W/8Ohm subs per amplifier. A pair of subs per side.I always use 4Ohms impedance as a minimum although the amps could go down to 2 Ohms.I do not prefer operation bellow 4 Ohms on this power level due to very high currents, and high cable losses. I have a rack-mount unit with 5pcs of XD-4000, 2for the middle-high and 3for the low section. It is a pretty compact small system. The power draw of this rack is bellow 63A even with strongly compressed heavy-duty musics.

Another thing is that these amps have built-in limiter/compressor system which work very well. It is almost impossible to drive these amps to clipping or distortion.

Finally the most important is the quality of sound of course... we have made several "A-B" compare tests and my amps get very very high results. They have real neutral sound and great dynamics, really powerful bass.
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Old 5th March 2009, 06:09 AM   #10
iand is offline iand  United Kingdom
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Default Re: PKN XD-4000

Quote:
Originally posted by uuv
I have measured the voltage of power supply: 402VDC
The voltage of end-stage is 167VDC in steady-state.
This amp is not sensitive for line changes ( i don't know because of the PFC or not) sometimes we have had very dirty line (~190V instead of ~230V) but the amps working! when the CD players do not :_)

So i am driving 4pcs 18" 1000W/8Ohm subs per amplifier. A pair of subs per side.I always use 4Ohms impedance as a minimum although the amps could go down to 2 Ohms.I do not prefer operation bellow 4 Ohms on this power level due to very high currents, and high cable losses. I have a rack-mount unit with 5pcs of XD-4000, 2for the middle-high and 3for the low section. It is a pretty compact small system. The power draw of this rack is bellow 63A even with strongly compressed heavy-duty musics.

Another thing is that these amps have built-in limiter/compressor system which work very well. It is almost impossible to drive these amps to clipping or distortion.

Finally the most important is the quality of sound of course... we have made several "A-B" compare tests and my amps get very very high results. They have real neutral sound and great dynamics, really powerful bass.
Sounds exactly what I'm looking for -- I'll be driving 2x 1200W/8ohm subs per side using BMS 18N850V2, and 4x600W/16ohm tops (line array) per side.

Ian
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