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PKN Controls XD4000 Amplifier Test Results
Excellent high power lightweight 1U Class D power amplifier from PKN Controls
This amplifier appears well designed and constructed on the whole. Some of the larger internal components such as reservoir capacitors and ceramic resistors are not mechanically supported and may work loose over time. At the threshold of clipping, there is severe oscillation on the top and bottom of the waveform caused by lack of negative feedback at such a high duty cycle. This oscillation ocurrs BEFORE front panel 'clip' (AGR) LED illuminates. The amplifier is a full-bridge class-D design and as such cannot be bridged. We could not measure THD for this reason. Low frequency square wave perfomance is very good, as is sine performance. First impressions were good, apart from the oscillation, but this only manifests itself at the threshold of clipping.
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All results taken with sine wave input into a resistive dummy load of 8, 4 and 2 ohms (where applicable), two channels simultaneously driven (unless otherwise stated), at the threshold of clipping. These results should be considered maximum 'continuous RMS' power ratings (>5 seconds). Distortion measurements, labelled THD%, are taken with an HP8903A audio analyser (80kHz Bandwidth). | |||||||||||||||||||||||||||||||||||
| Manufacturer | PKN Controls |
|---|---|
| Model | XD4000 |
| Weight | 9 kg |
| Power to weight Ratio1 | 423.7 W/kg |
| Notes | Severe Oscillation at clip, otherwise fine. Mains did not fall below 239V. Full Bridge class D, unable to measure distortion. 30-04-2010. |
| Manufacturer's Website | http://www.pknc.com http://www.pkndigital.co.uk |
1 Power to weight ratio is calculated by taking the average of the power measurements at 4 ohms, multiplying by the number of driven amp channels, and then dividing this value by the weight of the amplifier.
Click the images below for full-size versions
Description of Images:
- Oscillation on top and bottom of waveform. Full power, 1kHz. The vertical scale on the oscilloscope screen is half the actual output voltage because of the differential oscilloscope probe used.
- Oscillation on top and bottom of waveform. Full power, 40Hz. The vertical scale on the oscilloscope screen is half the actual output voltage because of the differential oscilloscope probe used.
- 1kHz full power square wave performance is excellent, with minimal ringing and fast rise and fall times. Oscillation on top and bottom of waveform. The vertical scale on the oscilloscope screen is half the actual output voltage because of the differential oscilloscope probe used.
- 10kHz sine wave, almost full power. Slight distortion, but excellent for a class D amplifier. The vertical scale on the oscilloscope screen is half the actual output voltage because of the differential oscilloscope probe used.
- 10kHz square wave, almost full power, showing slow rise and fall time. Good ringing behaviour.
