The PION C 250 D Power Cleaner

The PION C 250 D provides an extremely high level of protection against the large amount of high frequency noise that is almost invariably present on the incoming mains supply. It is derived from our original 8-channel power conditioner and is intended to be used as a dedicated filter for a single low power audio component such as a CD player, D/A converter or preamplifier. For audio components that have a greater power requirement, such as power amplifiers, we manufacture the PION C 1200.

pion250_1 As part of the research carried out during the design of the PION products, we examined a large number of commercially available mains filters and cleaners. We found that many such devices actually caused more problems than they solved and whilst they removed some noise, they often introduced other undesirable artefacts into their outputs. In the devices that we examined, we found the principle causes of such problems to be the use of an inappropriate filter type and under-specified components. The latter often appeared to be related to the need to meet a particular price point.

Learning from others' mistakes, we took great care to ensure that the PION C 250 D did not exhibit any undesirable behaviour. This involved very careful design of the filter circuit and a program of rigorous testing to ensure that the unit delivered the required level of performance across a wide range of operating conditions.

Top quality components are employed throughout. Over-size inductors are used so that they always operate well away from saturation. Using smaller inductors would have saved money and space, but would also have meant that they operated closer to saturation and therefore added distortion to the output mains waveform. All the capacitors in the design are operated with generous de-rating margins. This approach ensures optimum performance in the circuit and also improves the long-term reliability. The final selection of parts was made on the basis of extensive listening tests.

The unit's internal wiring also has a crucial effect on its performance. The PION C 250 D is wired with heavy-duty cable and connections are made with either high-pressure screw terminals, or soldered joints. No plugs are used, as the increased resistance they introduce would degrade the dynamic performance of the filter.

The PION C 250 D is especially effective at removing high frequency noise going up into the megahertz region, but the filter actually starts operating in the audio range. In order to provide the high degree of noise attenuation that the PION C 250 D achieves, it is necessary to restrict its power handling to 250W. Whilst it is intended for use with low power source components, it may also be used with small integrated amplifiers provided the power ratings are not exceeded. pion250_2

As well as very effectively preventing noise from the mains from entering the audio component it is driving, the PION C 250 D also prevents noise generated by a source component from being passed back into the mains, where it might degrade the performance of other parts of the system. This feature is an important consideration with digital equipment, which due to the high switching speed of their circuits can introduce significant amounts high frequency noise into their mains lines.

The entire filter assembly, as well as the input and output connectors, are encapsulated in a high density polymer material commonly used in the aerospace industry. This prevents vibration caused by magnetostriction and ensures that the unit runs silently. This is an important advantage with smaller listening rooms where it may be necessary to place the unit close to the listening position. It also protects the unit from external vibration and makes it totally immune to any microphonic effects. The polymer has the additional advantage of having a visually attractive stone finish.

The benefits noticed when using the PION C 250 D include a deeper and more natural soundstage and improved resolution of low-level detail. Background noise is also greatly reduced - inky black is how it is often described by users - and the reproduced sound takes on a more natural and relaxed nature, ensuring that long listening sessions are fatigue free.

To obtain the full benefit of the PION C 250 D, we strongly recommend that the filter be connected to the source component using our German Physiks PION N 3 ZF power cable. This has been specially designed to avoid the introduction of the high frequency noise often encountered with ordinary power cables. It also provides additional filtering of the incoming power and further attenuation of any noise generated by the source component.

The PION C 250 D Specifications

Maximum continuous power handling



Peak power handling



70mm W x 158mm H x 230mm D