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Reviewer: Kari Nevalainen
Analogue source: La Nouvelle Verdier with Ortofon RMG-309; EMT 930 with RF-297; Ortofon SPUs, Denon DL-103 etc. cartridges
Digital Source: Audiomeca Kreature transport, Sentec DiAna DAC (various mid-fi digital cables)
Preamp: Shindo Aurieges, Dynaco PAS (heavily modified)
Power Amp: Shindo Montille, custom 6V6 design, Sony integrated
Speakers: PHY/Fostex-based single-driver wideband speakers
Cables: PHY, Kimber, Belden, Supra
Power Cords: generic
Accessories: Sound Organisations rack, Gregitek equipment platforms, Final, SID etc. isolator pads
Mains treatment: None
Room Size: 4.5 m wide by 5 m long by 2.8 m high, one side wall partly open
Review Component Retail: BlackNoise Extreme 485€; BN 500 445€; BN 1000 540€; MiniBlack 225€

Nobody needs mains filters. Not having one makes nobody ill. Nor are filters the sine qua non of high-end sound. That does not mean that mains filters could not become a practical necessity. If top quality sound is what one wants, then unless one takes steps to ensure adequate mains filtering, top quality sound is not what one gets. This is how mains filters can be a far cry from "just accessories". But are they really?

At least the BlackNoise mains filters by Italian filter specialist Systems & Magic are. I'm not putting this forward in comparison with other filters brands. I have tried a couple in the past and judged their overall influence from indifferent to appreciable but my sampling has been far too small overall to make valid comparative statements. No, what makes me say that the Systems & Magic filters go beyond being mere accessories is that inserting them into my system made a difference. The sound changed.

The spice of this hobby, just admit it, are those moments when one unexpectedly, suddenly, within a split second realizes that there was a change in the sound. Like a crack in the backbone, like a strike of a lightning - without the tiniest hesitation, without the frailest uncertainty. Whatever it was, whatever other people might think, something happened. It's here amidst hearing differences that the ear is at its best. I wouldn't place any premium on this point if that happened all the time. But it doesn't. And there's the beef.

What makes reviewing mains filters so intriguing -- and challenging -- is that some people attribute 50% of the sound of their system to their AC mains treatment. Others agree upon the action of mains filters as altering the sound but they insist that what they do is counterproductive.

Passive filtering of different degrees
The Systems & Magic BlackNoise filters have been designed to be modular. That is -- and not unlike with some other filter manufacturers -- the people at Systems & Magic believe that for the greatest effect and best sonic results, dedicated filters should be used with different components in the same setup. No wonder then that instead of just one filter, Roberto Amato, the owner of Systesm & Magic, sent me four: the Extreme, 500, 1000 and MiniBlack. He also included a very handy phase finder, the €25 Phaser which I left out of this review, however.

What filter to use with what gear depends on power demands. The MiniBlack, 500 and 1000 are meant to be used with anything from small power amps to sources. The Extreme is for low-wattage gear only such as phono stages and digital sources. The 2500 is an ideal partner for demanding high-power amps. It should perhaps be noted that the wattage information in the specifications does not by itself tell you how much power your component will actually drawb during playback. In order to assess actual power consumption the proper way especially in case of big power amps, more info is required: the speakers' sensitivity and load behavior, the desired sound pressure level, the room's dimensions et al.

Apart from the MiniBlack, these filters have two outlets (compatible with Italy large and small; USA without the earth pin; and Schuko) of 16A each. The power inlet is a standard IEC. Two outlets enable connecting two sources or monoblocks to the same filter. According to the manufacturer, there's no adverse interaction between any two outlets but warns against power cords with inbuilt passive filtering of any sort because the interactions with the BlackNoise filters are unpredictable and hardly favorable. The best mains cables will be shielded ones with a good conductor cross section. The Systems & Magic product catalogue features a series of their own power cords (BlackWire, GoldWire and more).

BlackNoise filters are fully passive, using four progressive filtering stages on neutral and live and two on the ground. The circuitry consists of 30 discrete components (double metalized polypropylene caps, toroid-shaped inductors and more.) Specific filter characteristics vary from model to model. For example, the Extreme filters AC mains harmonics by 3dB at 1.8 kHz and is 60dB down at 20kHz (these figures are from the manufacturer's website). By comparison, the 3dB action of the 1000 kicks in at 3.2 kHz and at 20kHz is down 55dB. As a rule, the highest capacity filters filter less than the low-capacity filters. The least expensive MiniBlack applies less harmonic filtering than the other models but equals the 2500's power delivery rating.

Between live/neutral, neutral/ground and live/ground, the filters also protect against voltage spikes, disruptive pulses and such from 250V upwards, with an activation delay of less than 25ns. A resettable thermal switch instead of a more common fuse handles in-rush currents when components are first switched on. The chassis are made of 4mm thick anodized aluminum. The BlackNoise filters are hand-made, rather heavy and cool-looking. The manufacturer gives a five-year warranty on all models.

The sound department
Why mains filtering? For two oft repeated reasons. The mains contains HF noise and other unwanted components, filtering of which is beneficial to the perceived sound or is thought to be since the listener's ear should be the final judge here. Second, hifi gear, digital in particular, allegedly pollutes the mains with its own noise which is why decoupling such gear from the rest of the system is considered desirable. The BlackNoise filters carry out both tasks but is their effect truly beneficial?

The answer is affirmative and I could easily finish the review here. The sound changed, I largely welcomed the change and I wouldn't want to go back. What else is possibly required? I know, it's not enough to assert that the sound got better and then not to be prepared to elaborate on how it did so. But to be honest, I'm a little bit fed up with so-called critical listening. If I was asked which one I'd choose, the filtered or unfiltered sound, but wasn't allowed to say the filtered one unless I was able to abstract my evaluation into analytical components, what is that all on about? It's sometimes perfectly legitimate to have a pro attitude without an attendant epistemic duty to explain what the attitude is based on. Surely it's possible to like a certain landscape without knowing exactly why. My daughter does it all the time.

Anyway, before describing the effect of the filters in more detail, let's consider the magnitude of difference the BlackNoise filters brought about. Was the change in sound similar to the difference between an average and excellent i.e. phase-coherent and distortion-free tweeter? Yes, something like that. Naturally, this measure is intelligible only to those who've been in a position to compare tweeters under controlled circumstances.

Like the difference between an average recording and an especially good one? No. The change was not of the same nature nor as obvious - but in a sense equally dramatic. Like the difference in the inner tone color between high-quality tube preamps? Yes, very much so. In general, the change was not something easily observable by and explainable to non-audiophiles. But for the connoisseurs, that 'extra something' will have to be obvious. Audiophiles have unconscious expectations about how their systems sound. If a new sound clashes with their expectations, they instantly recognize it even though it remains mysterious to outsiders. It's very much like the car fancier who is attuned to the tiniest changes in operational noises of his favorite ride which his passengers won't hear even though he's attentively pointing them out.

Back to hifi. The impact of mains filters is, perhaps, best described with four questions: (1) did the sound become more airy?; (2) was it more detailed, including the oft-referenced blacker background?; (3) was the soundstage more extended?; and (4) was the reproduction of dynamic gradations unaffected or even improved?

With regard to (1), (2) and (3), the answer was yes, together and separately. As to these three factors, it's much more interesting to study the impact of each filter than to split hairy adjectives. I began by plugging the Shindo Montille or Marco 6V6 amps (both push-pull 10 watters) into the 1000 or MiniBlack, then added the 500 to the Aurieges preamp and finally the Extreme to my Audiomeca/DiAna digital source components.

While I agree with the manufacturer that the fingerprint of each filter is similar, i.e. that they all effect the same kind of sonic quality, my experiments point to the conclusion that the strongest fingerprint belongs to the BlackNoise 1000 followed by the MiniBlack. That is, in my system the most effective filters were those used on the power amps. I'd almost say "by far" but that would be an overstatement. Still, it was the 1000 and MiniBlack that almost stopped my heart. If I had to put the rest in order of importance, I'd say the 500 with the Shindo preamp had a greater impact than the Extreme on my CDP(or Verdier turntable for that matte), suggesting higher efficaciousness with increased power draw. But that was my system. Other systems may yield a different sequence.

At one point, I first connected my 200wpc Sony integrated into the 1000 and afterwards let the Extreme filter the CDP. The results were the same. The 1000 bettered the Sony's performance in many respects -- better focus, darker background -- but the extra good coming from the Extreme was meager.

In handling other business with my colleague Markus Lammenranta, I also asked him to check out whether the Extreme or 1000 would do anything for his system. He too had had some contact with mains filters/conditioners in the past but had failed to be impressed. After two days, he wrote back: "Audionet PAM phono preamplifier and Extreme? I could detect no difference whatsoever. With the NuForce Reference 9SE monos filtered with the BlackNoise 1000, the effect was remarkable. The sound got significantly better. Especially the stereo image was now deeper, the stage was more stratified, the sound gained more overall realism. Instruments stuck out from the group and were located distinctively. The soundstage was sturdier and its dimensions more plausible. Without filtering, the focus was in the line between the speakers, the image was higher but more two-dimensional. The Arcam FMJ CD23 through the Extreme gave parallel effects but the improvement was less meaningful. All in all, the benefits with the NuForce Class D amps incontestably met the criteria for a rational investment."

The coat's other side
Even though the 500 and Extreme changed things less than the 1000 and MiniBlack, I generally wasn't against having them in my system. I often ended up listening to music with every active component filtered thinking, "this is how it should be". At the same time there was no doubt that the impact of the BlackNoise filters was cumulative and with this we come to the obligatory part of any filter review. Roberto Amato calls it a cultural fact of life or "matter of fact". By that he means that every consideration, every review of AC main filters always raises the question of "dynamic problems".

I'd not dare meet Saint Peter at the Pearly Gate if I denied that I too felt the presence of the dynamic problem. My listening notes include characterizations such as "softer", "tamed", "less edge", indeed "filtered", the more so the more filtering was applied. What was this? It wasn't easy to get a grip on this phenomenon. I was constantly worried that I'd mistake this quality for something else. If someone asked me to point my finger to a musical peak which these BlackNoise filters demonstrably attenuated, I'm not sure I could. It's not that the wide dynamics of a grand piano were shrunk back to an ordinary piano. And yet, something was subdued. With the filters connected, it was possible to turn the volume knob two three clicks higher up without the sound spilling over, without the tenor saxophone getting overly harsh etc.

Despite the less boisterous character of the sound -- or whatever that was exactly -- especially when all the mains supplies were filtered (and much less so only on the power amps), I wasn't worried. The advantages in other areas were so overwhelming that whatever energetic damping there was at play, I could wipe it off my consciousness and go on with listening to the generally more listenable sound.

The Systems & Magic BlackNoise mains filters proved that my conception of mains filters was in dire need of revision. These reasonably priced filters, relatively speaking -- the 1000 and MiniBlack in particular -- noticeably increased my appreciation of the sound of my system. And although the normal happened i.e. the assessment of the amount of improvement diminished over time because that's how the ear works (just like a sleeping cat can ignore the sound of a nearby rock drill but suddenly flinches at a quiet rustle), I still stick to my initial awakening and impression. The sound changed. For the better. Pretty magical!
Manufacturer's website