Review: Telos Audio GNR and QNR – Quantum Noise Resonator

Review: Telos Audio GNR and QNR is not outrageously priced and it has been the discovery thanks to easy electrical installation of the system.
4.5/5 - (2 votes)

Review: Telos Audio GNR and QNR: For 15 years, this Taiwanese company and its director Jeff Lin have sought to improve the sound of music equipment, using the best designs and materials in the part in which they have specialized: the electrical supply and the ground connections. of the system devices. On their website we can review some products, dedicated to grounding or “grounding” in English, or the phase (they have an active filter for USB socket of computers), in addition to some more esoteric for magnetism, component filming, fuses, terminals for unused connectors … and so on. We will focus here on two products that deal with the power supply of our equipment: the GNR (for “Grounding Noise Reducer”) and the QNR (for “Quantum Noise Resonator” or quantum noise resonator).


The Telos QNR “Quantum Noise Resonator” despite its name, let’s say esoteric, comes to be a filter for the power supply current. It is a compact box (approximately one square inch) with only the connection to the network, and a translucent cover that allows you to see the circuit and, when it is connected, green and a blinking blue LEDs indicate that it is running, making its function. It is a “parallel” filter, that is, it will be plugged into the same power line where we have the equipment, for its best effect, but it is not inserted into any connection. Thus, from the outset, we can be sure that it will not have any limiting effect on our amplifiers, which is usually the first and most common negative consequence of other filters that are interleaved and, in addition to eliminating possible noise from the line,

Jeff Lin has been experimenting with circuits that do this for a long time: basically, it detects noise and spikes on the power line, especially above 1 kHz, and eliminates them. It has different passive filters but also an active chip that detects distortion in the line and generates a synchronized signal that compensates for the distortion in reverse phase, to leave the supply wave as pure as possible. It is now its “three point one” version and they highlight the use of closely selected components, which increases the cost by discarding those that do not comply. The result, they say, is that the system reduces its basic noise level by improving the clarity of the sound, making it softer.


Let’s move on to the Telos GNR “Grounding Noise Reducer”: it is a larger component (39 centimeters wide) more complex and does include connections in addition to the power outlet. It has six rear sockets, three on each side, using WBT 0703 NextGen speaker connectors, where we will connect the cables that connect the Telos device with the chassis of each component of the equipment. For that, they recommend using the one on one side for analog devices and the other for digital ones: the translucent cover reveals two symmetrical circuits, each one dedicated to the three connections on its side, as well as a central circuit that, as we will now see, is the “ processor”. Each side plate is actually a filter like the QNR, with its small LED lights in a circle, I understand that each one dedicated to compensating the connections on its side, and I say “I understand” because although Telos gives some explanations about their systems … they leave a lot to explain. The rear houses filters for each ground connection (with a visible coil as the most striking element).

The central board contains the CPU that monitors the voltage detected at each ground terminal (connected to the chassis of the equipment’s apparatus) and compares it with its ground (connection to the power supply network) and to the neutral pole of the latter. But the land of domestic installations is, in the best of cases, prepared for safety issues: it kicks off the automatic if something goes wrong to avoid electrocution, or it protects in the event of an electrical storm. But none of that is optimal for the sound of the equipment and noise gets there. Neither is the neutral of a domestic installation what it should be: there are leaks and depending on what has been connected to the installation (refrigerators, motors for dryers or heaters, low-quality power supplies …) they put noise on that line from the “live” line.

By connecting the chassis of different devices to the terminals, at the beginning we achieve a stable “passive” grounding: we will prevent currents from flowing through the cables that connect them. For that, it is important to use cables that are better conductors than the audio ones, and to ensure the connection to that chassis: if it does not have a dedicated ground, it will be necessary to find a strong screw for it or even install one. This is how other passive “grounding boxes” work (there are quite a few), using precious metals to pave the way for these currents. It is convenient to use quality cables and equivalents, that’s why Telos sells its own (up to esoteric levels).

This Telos goes a step beyond the passive chassis connection: it monitors potential differences, and the neutral line, and offers a reference voltage that is actively corrected with precision. Telos assimilates it to using a precision clock in a digital player, but in reality it is more important than that because, if it works, it ensures that each device and each circuit will work optimally, without noise on the power supply and above all without noise on the earth, being this really stable. In any RCA connection, for example, if the chassis (connector ground) fluctuates, the signal (at the tip) is distorted. In fact, according to Telos, using your GNR is equivalent to using a dedicated power line for the equipment, isolated even from the rest of the house.


I confess that I took this test with a certain skepticism since I am not a friend of testing cables or systems of this type. When I have tried them and the level is high, the advantages become clear, but in “my” team it bothers me to think that I could invest more in “accessories” than in “components” … even if the result was better (personal mania perhaps). But on the other hand, logically I was interested in knowing how much (and how) the Telos could improve my equipment, which also do not have exorbitant prices and also their “mini” versions are reasonable.

Telos Audio GNR and QNR

I started testing in the living room, with worse acoustics but better electrical installation: a tested ground and a dedicated line from the main box. First it was up to the little QNR, and remember that the advantage of this “filter” is that it is not inserted in any connection. It connects as one more device to the main power strip of the equipment, and I did. They recommend that it be “centered” and so I proceeded: central connection of the strip and located more or less equidistant from sources and amplifier. In this equipment, despite the tube amplifier, I have practically no background noise (the Ars Sonum are particularly quiet): with the volume turned up you have to get within a foot of the speakers to appreciate something. With the QNR in, 

But I cannot say that when I connected it I did not appreciate any change in the sound, on the contrary. To start with, there is a certain effect of greater cleanliness or clarity, which I remember having noticed with a filter that was also “parallel” (the Nordost QRTs that must be several). But above all another effect caught my attention: the music was more “ordered”, the scene was more precise, it even gained depth. The words of a vocalist were more intelligible, the notes of an instrument more precise… The music seemed more “fresh”, and when I disconnected the Telos it seemed that a gray veil appeared that I did not appreciate before. Every time I tried “sin” the music seemed boring to me, it skipped tracks and I was really looking forward to connecting it again to see if it was. And yes, that was it.

Telos Audio GNR and QNR

All this reminds me of an effect that I have already appreciated before: when in a system you improve the digital source, and I mean the transport (either optical or network player). There will be those who say that “they are ones and zeros” but possibly they have never done this test in minimal conditions, because it is clear that something is happening with that digital information. Some fonts are clearly better, and it shows a lot in that superior “order” and precision. The basement equipment, with a different source, amplifier and cabinets, gave me exactly the same result: with the QNR connected we have an even more noticeable order and gain in depth of the scene thanks to the better acoustics in this case. 

It was the turn of the star of the test: the Telos GNR or “Grounding Noise Reducer” as I already indicated includes two filters like the QNR inside, so that we already know what to expect, but it adds a connection for the masses. and a “control” of these. To connect the chassis of the devices to the rear terminals of the GNR, Telos sells cables designed for that: on the one hand they have the connector provided for the device (RCA, HDMI etc.) but only its “ground” is connected that on the other side of the device. cable goes to a speaker type terminal, for the Telos. As Audio Elite, importer of Telos, he lent me some much fatter cables but “terminal by terminal” I prepared some RCA-terminal myself based on some scrap of old or unused cable. I connected everything,

So I had to disassemble those cables and assemble the Telos, of much larger section and better qualities, but I must say very rigid and uncomfortable to position. In addition, to connect them, you have to look for strong screws or solid connections in each chassis, more complicated by the rigidity of the cables and the size of their connectors … Once the test was passed, the test with the tester gave the same result: everything connected to the millivolt . Would these cables do something different if you couldn’t measure the difference? 

You are right. Either the difference is below what I could measure, or it is a “dynamic” issue (not static potential differences). Or, as I suspect, it is important that the ground connections are of higher quality (lower impedance) than the line ones so that the eddy currents are actually evacuated there and are not distributed with the cable connections between devices. But now the presence of the Telos Audio GNR was noticeable in the team. Where I noticed it the most was in the living room, I don’t know if because there the Telos Audio GNR has a ground to use as a reference, or because the boxes (closed Merlin TSM monitors) are not too much “body”. Because that was the biggest noticeable difference: more body, as if the boxes had a few more liters of volume. They did not give lower in the sense of greater punch, but more natural, rounder, more present notes.

Telos Audio GNR and QNR

Telos Audio GNR and QNR – Conclusion

Just as to optimize the acoustics of a room, you must first have the equipment well placed and use “passive” materials, before trying something else (such as equalizing), the electrical installation of the system has to be as good as possible: preferably with dedicated line, good land and good connections. But on this good basis, Telos offers us devices capable of going further, thanks to its parallel filtering and therefore extensive current limitations, and also thanks to its control of the earths. The Telos QNR is not outrageously priced and it has been the discovery.

There is also another GNR Mini model, with two sockets (one circuit) and without the “filter”, which can form a very interesting pair. The QNR is very easy to test in a team to decide if it is worth it and it stays or not, and then we could try with that GNR Mini … The RRP of the Telos GNR skyrockets, although the offer that the distributor now offers may be a good opportunity, because in theory it is equivalent to two QNR and as many GNR Mini.

The “little ones” should be tested for sure: recommended.


+ Parallel filtering without current limitation

+ Efficient and easy to test the QNR

+ Complete (filter plus earth) the Telos Audio GNR

– Need to connect extra cables from the devices to the Telos Audio GNR

– “Good” cables too stiff and expensive