– FALK VISARIUS, hifi-ifas.de

Translated from German.

There are a bit of “accessory weeks” at the HiFi IFAs, it seems. Bernd had a hard time with the NuPrime Omnia SW-8 HiFi network switch at the North German HiFi Days , so he took it with him to the test – and immediately wrote a report for interested readers. A tight workload for Bernd after two jam-packed HiFi days in Hamburg. Stefan was also impressed by the topic of accessories at the NDHT 2020 – which he talked about in his “HiFi Tuning” tourgives testimony. So why not a NuPrime double feature this week with the Omnia SW-8 HiFi network switch and the AC-4 power conditioner (RRP 849 euros), which I’ve had as a guest in my listening room for quite some time – and actually also no longer want to miss. But more on that. I don’t want to spoiler.

approach

We have dealt with the subject of electricity from time to time. A sure sign that we are interested in the topic. And a sure sign that the hi-fi IFAs believe that the power supply can have an impact on the sound of a hi-fi. It would be nonsense to spend your time doing things you think won’t get you anywhere. That’s why it would be nonsense to continue reading this report if you think the influence of the power supply on hi-fi devices is complete nonsense. In this case, that would be wasted time. I don’t want to convert anyone, but I think what I experienced with the NuPrime AC-4 is worth reporting.

Likewise, it is difficult to hold a scientific paper on the subject of electricity within the framework of our blog. We don’t want that either. Interestingly, such a treatise can be argued about just as well afterwards as a field report based on (subjective) listening impressions. I would therefore like to confine myself later to the listening impression.

What I would still like to bring up from a technical point of view is the following consideration. Electrical devices are designed for a specific AC voltage. Important parameters are the voltage and the frequency. And that the AC voltage should follow a sine wave. None of this is a matter of course in our power grid. On the generating side, i.e. in the power plant, efforts are extremely high to reproduce these characteristic values ​​exactly, since they also have an influence on the load distribution in the power grid. What arrives later in the house, at the socket, at the device plug, is a completely different matter and may no longer have much to do with the ideal. This means that the electronics of the device, first of all the power pack, does not get what it “expects”.

The power grid in front of the house connection is subject to daily fluctuations caused by commercial consumers. The network in the house is subject to similar effects due to different load distributions, and power supply units and transformers from other consumers also interfere – and mess up the electricity with high-frequency components. Apart from the fact that there is a different voltage at all sockets in the nation, the sine of the AC voltage is not a beautiful sine, but a structure that wriggles around the ideal sine and is also mixed with DC components.

The hi-fi devices in a chain have to cope with this somehow. In their electronic guts, an electronic signal eventually becomes a (sound) frequency, from which the loudspeaker then creates mechanical vibrations that we perceive as sound or music. All of this will work out somehow. But in a hi-fi system, music shouldn’t just sound like something. The basic consideration is that this can be all the more successful the better the quality of the input variable “mains current” is, from which ultimately everything (!) further is generated.

And that brings us to the NuPrime AC-4 power conditioner, whose task is to bring the mains power supplied to a state that is a good step closer to ideal. And he cuts a good figure at it.

The NuPrime AC-4 has the slim format of a NuPrime device and thus fits nicely into the picture of a hi-fi system. Be it from your own device family or from other manufacturers. Personally, I really like the shape of the case with the distinctive bevel on which the brand name is written. Even if the display on the front panel looks a bit rustic in contrast. But it fulfills its purpose in a way that is easy to read and can also be switched off. When unpacking, the AC-4 fits comfortably in your hand, so setting it up is fun. Since the cables are all already where the action is, the NuPrime AC-4 is permanently connected and wired to the devices. I decide to first listen to the AC-4 extensively and then dare to compare it. This also leaves time to devote a few lines to the technology.

Technology

The filter design of the AC-4 power conditioner is designed to process the current with minimal losses in dynamics and bass reproduction. The AC-4 has two pairs of AC sockets (a total of four sockets) for different device types:

1) Two “source” power jacks dedicated to small signal processing devices such as DACs, preamps and CD players. They are designed for an output current in the range of 3A to 8A with an extremely efficient 7th order LC filter with a maximum filter performance of 1,000 times.

2) Two “Power” mains sockets for devices with high performance requirements such as integrated amplifiers and power amplifiers.
The outputs deliver output currents in the range from 10A to 15A. A 5th order LC filter with 10-50 times the filter performance was developed for a maximum current of 27A.

To maximize current flow, the inductors are wound with 1.6mm copper wire. The four power sockets are gold-plated Furutech FPX. A trigger input and output as well as overvoltage protection are useful additional features. The AC monitoring provides information about the current mains voltage, current and power output via the front display that can be switched off.

listening impression

The NuPrime AC-4 actually ran in my system for weeks without giving it much thought. Why? I need a power distributor anyway. This means that the AC-4 is not an additional device that I had to bend into the setup or whose operation I had to arrange separately. On the other hand, dealing with such effects is not what I want to break over my knee after a long day at work. A little leisure has to be there.

So I lay in wait. Until the opportunity arose. So one weekend, when I was relaxing and listening to music I was familiar with from our cable tests, I switched back to a standard multiple socket. The game partners at the slots are the MERASON DAC-1 digital/analogue converter and the SPL Phonitor x, which serves as a preamplifier, at the small signal places. The other two places are occupied by Dutch & Dutch 8c active loudspeakers , which I feed analog with music. So the NuPrime AC-4 powers the signal in the last three stages of processing. So the good thing is that the desired effect of the AC-4 works evenly on different components of the system.

So I listen first with the AC-4, then with the standard bar, then with the AC-4 again and so on. For this I use the same titles that I already know from one or the other cable test. “Five Years Time” from “Noah And The Whale”. A song that, apart from the fact that I find it somehow amusing, also has something to offer musically. “Point” with “Map”, which inspires me onomatopoeic and with many small sound events and last but not least the well-known “O-Zone Percussion Group” with their “Jazz Variants”. A lot happens here in terms of coarse and fine dynamics as well as timbres. A system must be able to be measured against this.

When changing the power distributor, you quickly get a gut feeling. The music with the NuPrime AC-4 just sounds more correct to me. I’m looking for details that prove it admirably.

In “Noah And The Whale” the sound events get more contours. Individual events are better distinguished. The whistle is better outlined and appears a little more natural with fine “blowing noises”. Due to the added structure, the room appears more organized, individual sound events take up their position more clearly in the room. When the bass and bass drum come into play, the sound becomes crisper. The voices also seem more natural. Perhaps there are fewer artifacts in the signal to irritate the ear. The effect is minimal, but still clearly noticeable.

This is confirmed with “Point”. The room opens up noticeably. The abundantly rich bass goes deep, but it loses the tendency to boom and becomes crisp. Sidsel Endresen’s voice is magnificent. coos.

Now for the endurance test. “O-Zone Percussion Group” gets going and brings more joy of playing into the listening room on the AC-4 through finer accentuation and finer drawing. The impression at the hardware store socket: That’s all well and good, but if you don’t feel like playing, then stop. This is happening on a very subtle level, of course. But that’s my feeling and I’d rather switch back to the AC-4.

In the “Jazz Variants” the influence of the AC-4 in the area of ​​fine dynamics comes across much more strongly. The effect is less noticeable with clear sound events, such as with the bright xylophone. Rather with base drums or timpani, where the head resonates and which creates fine arcs of tension when it fades away.

I don’t want to finish my test without a classic. It should be “Baba Yaga” from “Pictures at an Exhibition” – the original version for the piano, at which Evgeny Kissin takes a seat for me.
The setup with the AC-4 gives the piano playing a higher value. With the 08/15 socket, there is a slight feeling of “tinkle” that doesn’t do justice to the artist and recording. The sound seems a bit hasty. That’s not to say there’s no room or dynamics with the cheap power strip, but it all loses its shine compared to the NuPrime AC-4.

Since my brother-in-law is within reach and he can’t escape quickly enough, I involve him. It’s a bit unfair, of course, because it catches him off guard, but that makes things interesting again. He’s heard a lot from me, but he’s certainly not a hi-fi nerd. What is he thinking? Interestingly, after switching back and forth a few times, he finds the cheap bar more appealing. Which amazes me. In the conversation we find that we have perceived similar things, but what we have perceived has had a different effect on us. The cheap bar lets through rather coarse dynamic effects in the music and seems to sound louder as a result. That was spontaneously the appealing point for my brother-in-law. Almost between door and hinge. The Nu-Prime AC-4 relativizes coarse dynamic effects, because it contours the bass more and thus works out impulses better. This also creates more fine dynamics, which makes the music more natural and atmospheric. That’s what excites me when I concentrate on immersing myself in the music. And it’s the effect that I really don’t want to miss anymore.

Conclusion

Dealing with the current is certainly not the very first thing that the hi-fi fan has to tackle. In the beginning, a cleanly constructed power strip will certainly do the trick. If the value of the system reaches a region that puts the purchase price of 849 euros into perspective and detail optimization is pending anyway, the Nu-Prime AC-4 is a worthwhile investment. The music gains in authenticity. With concentrated listening, the music lover is rewarded with more details, fine dynamics, space, naturalness and simply liveliness. A worthwhile attempt even for skeptics.

Link to the review --> https://hifi-ifas.de/test-nuprime-ac-4-power-conditioner-netzfilter-entspannt-euch