Nubert nuConnect ampX Review – Powerful universal talent in Class D with room correction

Modern hi-fi systems are characterised not least by the fact that they offer a wide range of possibilities in the most compact form, while at the same time taking innovative paths for the most flexible use possible. This is exactly the case with the Nubert nuConnect ampX, the smallest stereo integrated amplifier from Nubert electronic GmbH to date, but which in our test presents itself as very, very mature.

For no less than 45 years, the German company Nubert electronic GmbH has been known as a proven specialist for loudspeaker systems. For a long time now, the company has no longer limited itself to purely passive systems, but rather the area of active loudspeaker systems has been an immensely important business area for the company from Schwäbisch Gmünd for years. What was initially considered to be a semi-professional and professional application in the field of media production in general, has increasingly developed into a product genre that has also gradually generated growing interest in the hi-fi sector, as more and more users recognise the advantages of such solutions.

But why do we speak of active loudspeaker systems in the first instance when we are talking about a stereo amplifier? Well, the answer is quite simply the close relationship that the electronic systems at Nubert electronic GmbH have with the active loudspeaker systems, especially those of the Nubert nuPro X series, in many ways.

For example, it was almost obvious that the experience gained from years of developing active loudspeaker systems would be used to create independent electronics. After all, the passive loudspeaker systems in the product range can also benefit from what is often regarded as the most powerful argument for active solutions, namely the fact that electronics and speakers come from a single source so that they are optimally matched to one another.

A further exciting aspect around the electronics from Nubert electronic GmbH is that they gradually started to build up a flexible, modern platform, starting with the active solutions including the new electronic components up to the passive loudspeaker systems, thus ultimately covering the entire product range.

A perfect example of this is the Nubert nuConnect ampX, the latest and smallest addition to the electronics series from Nubert electronic GmbH.

At first sight a stereo integrated amplifier of compact design…

As just described, the Nubert nuConnect ampX is the smallest addition to the electronics series from Nubert electronic GmbH. The Nubert nuControl 2 preamplifier alone is easily twice as big and of course can’t do without a partner, be it the comparatively slim and yet remarkably powerful Class D power amplifier Nubert nuPower D or the Class AB powerhouse that is available with the Nubert nuPower A.

To get straight to the point, the Nubert nuConnect ampX has dimensions of only 23.4 cm in width and 6.7 cm in height. The bottom line is that it is also only 23 cm deep, even if this includes the front panel controls and rear connectors. It weighs only 2.6 kg.

The Nubert nuConnect ampX is thus a really very, very compact system. Nubert electronic GmbH is thus entering a completely new, but with regard to the developments on the market extremely exciting and also increasingly important “weight class”, namely that of so-called mid-sized hi-fi.

Such HiFi components in Midi format are becoming more and more popular with customers, because if you live with notebooks, smartphones and therefore all modern, small and yet extremely versatile solutions every day, you also want such smart, elegant and compact solutions for audio instead of bulky HiFi castles. It is not the intention to build the living room around a hi-fi system, the customer rather wants a system that can be integrated into his living environment, as simple and harmonious as possible. And this is exactly what Nubert electronic GmbH does in a particularly remarkable way with the Nubert nuConnect ampX.

Versatile integrated amplifier and wireless connector…

The fact that the Nubert nuConnect ampX is not just a stereo integrated amplifier in a compact form, but is capable of much more, is already in its product designation. The name identifies it as part of the Nubert nuConnect series, and with it the new platform strategy mentioned in the introduction, which the company from Schwäbisch Gmünd wants to establish across the widest possible range of products.

The idea behind this is as simple as it is consistent: to be able to combine as many components as possible simply and effectively with each other, in this specific case solutions such as this stereo integrated amplifier with the active loudspeaker systems from Nubert electronic GmbH, above all of course the current Nubert nuPro X active series, which ranges from soundboards for optimum TV sound to classic active loudspeaker systems in the form of compact shelf loudspeakers or really powerful floorstanding loudspeaker systems.

Of course, many manufacturers are currently pursuing such approaches, especially in the area of streaming. But Nubert electronic GmbH clearly does not want to go so far as to establish a new streaming platform. Rather, they are relying on extremely powerful and thus robust and reliable wireless technologies, thus deliberately leaving out the topic of “networks”.

A sound manager…

Another important aspect of easy integration into the living environment is clearly the possibilities of flexible signal processing. Anyone who wants to integrate a hi-fi system as harmoniously as possible into their living environment will probably give little thought to whether the living environment is acoustically optimal. Here too, of course, one can take the view that optimum results can only be achieved under optimum conditions, or one can provide the customer with a tool that guarantees very good results under the given conditions, such as a compact stereo integrated amplifier that, like the Nubert nuConnect ampX, acts as a “sound manager” and can therefore be adapted to individual circumstances in the simplest possible way.

So much for the general classification of the Nubert nuConnect ampX stereo integrated amplifier and its basic thrust, let us now look at the solution in detail.

Based on the Nubert nuPro X series

As already mentioned, it was of course obvious that the development of the electronic components should be based on technologies and experience of the active loudspeaker systems. For the Nubert nuConnect ampX, the Nubert nuPro X series was of course used as the basis, so that a very powerful amplifier platform could be used. However, it was of course necessary to expand and adapt it a little bit to finally create a modern stereo integrated amplifier.

Compact, yet powerful and flexible…

Of course, Class D is used here as the technology for the amplifier, as this is the only way to combine two essential factors, and was more than enough power in very compact dimensions. After all, the Nubert nuConnect ampX delivers 110 watts twice, and this on loudspeaker systems with an impedance of 4 ohms, so that a multitude of speakers can be driven without any problems, right up to solutions that, at least in terms of size, seem to be in a completely different league than this small powerhouse.

The housing is made of aluminium and anodised in black. The cooling is purely passive, with ventilation slots on the bottom and cooling fins on the sides.

At the connections here, an analogue input is initially available as a pair of RCA sockets, and there is also a further pair of RCA sockets that can be used to connect a record player, i.e. the Nubert nuConnect ampX has an integrated phono preamplifier. The special feature here is that it is a solution designed for both MM and MC pickup systems, which is actually a novelty in this price class. Whether MM or MC pick-up system, the choice is made by means of a toggle switch on the back. Digital sources can be integrated via two optical and two coaxial S/PDIF interfaces, whereby signals with up to 24 bits and 192 kHz are processed. In addition, a USB-B port provides a direct connection to a PC or Mac, processing signals with up to 24 bits and 192 kHz. A USB-A port fulfills a particularly important task, namely the HDMI ARC adapter included in the scope of delivery is connected here. This makes it possible to connect a TV set directly to the Nubert nuConnect ampX and thus transmit television sound. Of course this adapter supports HDMI CEC as well as ARC (Audio Return Channel), so that the volume can be controlled with the remote control of the TV alone.

A very important “input” is of course the integrated Bluetooth module, which can be used as a source for smartphones and tablets, but also portable hi-fi audio players. It should be mentioned that the implemented Bluetooth 5.0 module not only supports the lossy SBC and AAC, but also aptX, aptX LL and even aptX HD. This not only guarantees a signal transmission in “CD quality”, with corresponding source devices even hi-res audio with at least 24 bit and 48 kHz is offered with negligible latency.

In addition to the obligatory screw terminals for connecting the speakers, the Nubert nuConnect ampX features a connection for an active subwoofer, and it also has a digital output, designed as a coaxial S/PDIF interface. This serves to supply a second zone, for example in the form of an active loudspeaker system from the Nubert nuPro X series. However, and this should be emphasized here, this also works “wirelessly”.

Two antennas are available at the rear, one of which is used for the Bluetooth module, the second for communication and signal transmission with active speakers of the Nubert nuPro X series and other solutions of the Nubert nuConnect series, both current and future…

Master or slave…

Communication is written in capital letters with the Nubert nuConnect ampX, which means above all that it is not a one-way street. So it is not that the small stereo integrated amplifier can only transmit signals to other components, it can also reproduce them from others. Accordingly, a distinction is made here between two modes of operation, master or slave. The signal transmission takes place on the digital level alone, at 24 bit and 96 kHz. This also applies to digital as well as analog sources, even signal transmission of the phono input to a second zone is possible without problems.

In practical terms, this means that the Nubert nuConnect ampX can be used in a room in combination with a pair of passive loudspeaker systems, for example in a living room. A record player can be placed there without any problems and the good sound while watching TV is also ensured. In the second room, such as the bedroom, for example, a pair of compact active speakers from the Nubert nuPro X series is used, and of course a corresponding subwoofer from Nubert electronic GmbH can also be brought into play.

Actively intervene in the sound process…

As already mentioned, Nubert electronic GmbH speaks of the Nubert nuConnect ampX as a sound manager, and rightly so.

The fact that this initially refers to a very special sound control system is clear from the very fact that this amplifier was developed on the basis of the digital amplifier technology of the active loudspeaker systems of the Nubert nuPro X series. The Nubert nuConnect ampX thus also has the same equalization that the manufacturer likes to call a so-called sound balance.

This is a simple bass and treble control, but it is not that simple. Instead of just radically raising or lowering relatively small frequency bands in the bass, midrange and treble by up to ten decibels, entire ranges are always included, so that the overall balance and harmony of the recording is maintained.

If you really want to intervene in the frequency band with pinpoint accuracy, you can do so using a five-band equalizer, and there is also a loudness function that is correct from a hearing physiological point of view. Depending on the volume, the bass level is only raised gently to moderately, thus compensating for certain deficits in the reproduction, but the overall sound image is not too drastically “bent”.

Simple, intuitive operating concept

From what we have reported so far, it is clear that the Nubert nuConnect ampX is a very versatile little fellow. Not only is it open to a wide range of sources and flexible for a variety of applications, it also allows the user to intervene in the sound process in many different ways. This of course requires a well thought-out operating concept.

For this purpose there is a rotary encoder and a single button directly on the front of the amplifier, as well as a generous OLED display that is always clearly legible. But is that enough for comfortable operation?



Yes, with this rotary encoder, one push button and a logical, simple menu structure, the Nubert nuConnect ampX is very easy to operate. Without detours you are quickly where you want to go, find all parameters immediately and it is clear without looking into the manual what has what effect.

Of course, an infrared remote control is also a must, with which everything can also be called up and controlled quickly.

However, the most comfortable way of controlling, especially when it comes to controlling the sound parameters, is probably the app that comes with it, the Nubert X-Remote, which is available for Apple iOS as well as for Google Android. Since no network integration is provided here, the connection to the Nubert nuConnect ampX is of course via Bluetooth.

Nubert X-Remote with Nubert X-Room Calibration

The App Nubert X-Remote reproduces all the options provided by the Nubert nuConnect ampX, whereby the developers decided to basically implement the concept of a classic remote control.

However, this is only one aspect of the app, but the most important one is that it allows for room calibration and thus optimal adaptation to the individual conditions in the listening room. This option is called Nubert X-Room Calibration and directly accesses the amplifier’s DSP-based signal processing.

Of course, this is not a matter of correcting propagation times in the room, as is the case with AV receivers in surround mode, but room calibration addresses one of the main problems of many hi-fi chains, namely bass equalisation for optimum low-frequency reproduction at the listening position. It is used to minimise so-called room modes, i.e. the effect where the bass appears much too “thick” or a “bass hole” occurs at the listening position.

Via the corresponding menu item, a test signal is reproduced, specifically white noise, for about one minute. The smartphone is placed at the listening position and records the signal, and the app uses this recording to calculate a tuning curve, which is then transmitted to the amplifier for its DSP and stored as a preset. So the calibration is almost automatic, at least the user does not have to contribute anything significant. Of course, a comparison between optimized playback and the original can be made at any time without calibration, and the app also displays the two curves – once in orange without optimization, green as optimized curve.

By the way, the app uses a fully parametric 10-band equalizer in the frequency range between 20 and 160 Hz. The aim is to achieve a curve that is as linear as possible. Nubert electronic GmbH expressly points out that the control range is +/- 6 dB in order to avoid overmodulation in combination with the other equalization. The Nubert X-Room Calibraiton cannot and should not be a panacea for really all acoustic inadequacies of the listening room

The only downer is that this room calibration is only available for the Apple iOS app, but not for Google Android. The reason for this is relatively simple and cannot be found at Nubert electronic GmbH. It is a fact that Apple iPhone app developers can assume that one and the same microphone is always used, whose specific properties are known and can therefore be taken into account for such measurements. In the world of Google Android, however, the situation is completely different, with each manufacturer using different microphones for their smartphones, many of which are also not among the most valuable. Getting to grips with this diversity would require an immense amount of effort, which ultimately cannot be justified.

Nubert electronic GmbH therefore decided to recommend the support of Apple users in their circle of friends and acquaintances for the setup, since the calibration only has to be done once and the tuning curve is permanently stored in the device. So as long as you don’t make any serious changes to the configuration or the listening distance or in the room, you don’t have to make any further measurements.

From the practice

For our test, we naturally tried out the Nubert nuConnect ampX in various configurations. First of all, it had to prove itself on KEF speakers, namely the highly demanding KEF LS50, the compact speaker systems of the reference class. We also relied on speakers from Italy, and once again, compact class speakers, the Chario AVIATOR Ghibli.

In addition, Nubert electronic GmbH kindly provided us with fine speakers that proved to be a perfect match in our test, namely the fine, graceful Nubert nuLine 244 floorstanding speaker systems, and so that the whole thing becomes really “round” towards the bottom, plus the powerful Nubert nuSub XW-900 subwoofer, which fortunately is equipped with radio and can therefore be integrated directly “wirelessly”.

First of all, there was no constellation in which the Nubert nuConnect ampX did not really perform well, which is by no means a matter of course in view of the very attractive price advertised, especially in conjunction with the considerably more expensive speakers from England and Italy.

But we were really impressed by the combination that Nubert electronic GmbH sent us as a kind of recommendation. We dare to claim that the price is not enough to put together something comparable, which should leave nothing to be desired for a normal living room.

The Nubert nuConnect ampX presents itself as a truly versatile stereo integrated amplifier. Of course, so many input options are not available here, there are solutions that offer much more. But, hand on heart, who really needs them? For many music lovers today, a streaming client is the very first and often the only source, and it can be integrated via the digital interfaces. Another big plus is the HDMI adapter, which is included ex works, making the Nubert nuConnect ampX by far the best option for first-class television sound. In combination with fine speakers, hardly any soundbar can keep up, especially not in this compact, affordable form. With the integrated Bluetooth module, here implemented in a technically flawless form, a smartphone, tablet, even a portable hi-res player and even a notebook can be integrated at any time as an extremely versatile source, making even the separate streaming client mentioned above obsolete. On Wusnch, a PC or Mac can also be used as source via USB cable. And last but not least, vinyl lovers will also get their money’s worth without having to purchase a separate phono preamplifier, no matter if they own a drive with MM or MC pickup system.

And, as mentioned many times before, it’s an extremely compact system, which means that the amplifier can be integrated effortlessly and discreetly into really any living environment. There is no excuse for not having enough space…

Nevertheless, the Nubert nuConnect ampX is surprisingly powerful and, as our test showed, can control a large number of speakers effortlessly. For an average living space, there is no need for more, especially when more compact speaker systems are supported by a subwoofer.

Finally, the possibilities offered by the Nubert nuConnect ampX in combination with other systems from Nubert electronic GmbH must be emphasised once again. The fact that the company from Schwäbisch Gmünd deliberately relies on solid wireless technology instead of a network infrastructure, yet still allows such a versatile and therefore flexible concept for the interaction of different components and the sound reinforcement of several rooms, is unique in this form and therefore a very big, fat plus point.

Last but not least, the operation around these functions, but also all other parameters is flawlessly solved, especially considering all the settings you can ultimately make on this small amplifier. Moreover, there is the right option for every situation, whether directly on the unit and via the remote control for everyday use, or via the app for more in-depth adjustments.

Last but not least, we still have to judge the sound. Without any further intervention by the DSP-based signal processing, it is clear that the Nubert nuConnect ampX is tuned very neutrally, so it performs very well on a wide variety of speaker systems and can work out their individual character. It delivers a remarkable dynamic response, even on speakers that are very demanding on the electronics.

The fact that one does not indulge in the stubborn audiophile doctrine here, and simply leaves it to the user to select his individual sound preferences, is a further plus point, although Nubert electronic GmbH has always held this to be the case with active loudspeaker systems anyway, and has also adopted it for the electronic components including the Nubert nuConnect ampX.

The exciting thing is, however, that here one has the opportunity to actually assume an almost neutral basis, since the corrective measures offered by the DSP-based signal processing are surprisingly effective in eliminating typical, tiresome problems of room acoustics.

For example, the sound may sound impressive from the very beginning, since the room is largely unproblematic, but calibration and the resulting correction in the bass range can open up a deficit or two. The bass might not sound as powerful, but crisp and accurate, and suddenly everything is exactly to the point. This also makes the overall sound image much more tidy and relaxed, clearer and more concise. On this almost neutral basis you can still “touch up” in one direction or another to achieve the desired sound. This also includes a function that we didn’t mention before, namely the discreet expansion of the sound stage, which is really fun when watching movies, for example.

In short, the Nubert nuConnect ampX is a stereo integrated amplifier that is a prime example of how modern, compact hi-fi systems can be realised. Simple operation despite unique, versatile functionality, from DSP-based signal processing including room calibration, effective, musically acting tone control, “communication” with systems of the Nubert nuPro X series and other Nubert nuConnect ampX systems as well as subwoofers, and of course a performance potential appropriate for use in a typical living room, all this speaks for this solution from Schwäbisch Gmünd.

Getting to the point

The Nubert nuConnect ampX really does reflect all the experience that the engineers at Nubert electronic GmbH have gained over the years in developing high-quality electronics for active loudspeaker systems. Their concept has already been skilfully transferred into real hi-fi bolides, but now also into an extremely compact, yet powerful and versatile stereo integrated amplifier. Outstanding features such as the extensive DSP functions including room correction, the intelligent “networking” with other Nubert solutions via radio alone, and last but not least an outstanding price in view of the functional diversity and quality lead to a clear recommendation.

The Nubert nuConnect ampX is a stereo integrated amplifier that is a prime example of how to create modern, compact hi-fi systems. Simplest operation despite unique, versatile functionality, from DSP-based signal processing including room calibration, effective, musically acting tone control, “communication” with systems of the Nubert nuPro X series and other Nubert nuConnect ampX systems as well as subwoofers, and of course a performance potential appropriate for use in a typical living room, all this speaks for this solution from Schwäbisch Gmünd.