Audiophilepure

https://www.soundandvision.com/content/thx-onyx-dac-headphone-amplifier-review

Competition? I had an AudioQuest Dragonfly Red, another $199 portable DAC/amp with MQA support, on hand. After running my playlist using all available DAC/headphone combinations, I concluded both were capable of clean playback at loud levels and could easily handle dynamic musical passages such as the drums-heavy final 30 seconds of Anouar Brahem’s jazz/world-music jam “Bahia.” Where the Onyx differed was in its slightly wider, more layered spatial presentation—something that bodes well for the portable gaming and movie-viewing THX touts for its DAC.

https://stereo-magazine.com/review/audes-st3000-review

In conjunction with the setup found in our small STEREO listening room, using the Audes „Isolator“ paid off immediately. While a stoic silence was being built up in the background, the actual sound stage seemed bigger, more spacious, more open and airy. Quite interestingly – and I had not necessarily expected this – it was also more dynamic, even in the bass! This even stayed true when a very powerful amp like the Musical Fidelity M8xi was in play; or even a 2 x 1000 watt THX power amp like the QSC USA 1310, sitting in the editor‘s home theater. Here, I would have expected overdamping, but Audes is actually even equipped for such an extreme task. While being ideal for sources, it is thus also suitable for larger voltage-consumers. Mastering very large Class A mono power amplifiers – or two QSC mono in a bridged setup (2620 watts sine into 8 ohms) – is something I would not have necessarily expect of it, but that also applies to other “power conditioners”.

This toroidal, balanced isolation transformer thus seems to be the uncompromising one-way solution that can help a system have more legroom thanks to interference decoupling. Taking it away from your setup is even more severe than the sonic progress achieved when implementing it; because you actually don‘t want to do without the Audes anymore – and the step back really hurts. It‘s not a cheap device, but should absolutely be recommended for excellent hi-fi chains!

When I introduced the REL subs and the DPS-4.1, I felt the power cords tightened the low-end spine of the system—not by an order of magnitude, mind you, but in a musically noteworthy way. There was a newly exposed, seat-of-the-pants energy from the Hans Zimmer soundtrack to The Thin Red Line, specifically on the brain-rattling Kodo drumming of “Air,” which added greater harmonic complexity and texture than before. 

I acknowledge that the home-assembly approach of the DPS-4.1 is not for everyone, but for those who possess some DIY chops, Furutech just might have the power cord for you. All it takes is a little elbow grease, and you’ll be rewarded with a cord that performs on a par with some of the top contenders, at a considerable cost savings. Unreservedly recommended. 

I can only give an enthusiastic thumbs-up to the superb products that HRS is manufacturing. Latvis’ consummate devotion to his craft has resulted in a range of devices that is more than worth auditioning. His HRS products offer a useful reminder that the task of isolating audio equipment cannot be dismissed as an ancillary consideration. It’s essential.

There was hum in my system! It was the dreaded 60 cycle hum. So was it caused by a faulty power supply, or a power transformer too close to a high gain amplifier? No, more likely the progenitor of this problem was electromagnetic coupling somewhere in the cabling. Experimentation narrowed my search for the source back to my preamp. As a rule, if the level of hum doesn’t change with changes in volume, then the problem is likely in a power cord or interconnect. In this case, swapping the power cord greatly reduced the audibility of the hum.

Hum, buzz, and static are probably the easiest noise issues to identify, but there are others, EMI and RFI among them, much harder to sort out. This is partly because they are more difficult to pinpoint when present but, interestingly enough, are very noticeable when removed. Anyone faced with system optimization will ultimately need to address noise issues and solutions. Noise masking of program material will increase fatigue, reduce dynamic range, waste amplifier power, increase distortion, and generate unnecessary heat. Noise can alter amplitude and phase, and inject spurious frequencies.

These are just some of the things that power conditioners are, ideally, designed to deal with, some more successfully than others. Power conditioners can, while removing noise, also change the character of your system, not necessarily for the better. As with any component, it is always best to audition a power conditioner in your own system before making your purchase.

https://www.monoandstereo.com/2021/08/hifstay-hardpoint-trinia-vibration.html

HardPoint was designed with the clear goal of not compromising the sound or altering the tonal balance.

What it does do, as you can read in the review, is help the sound projection achieve more focus, clarity, and better harmonic density. 

The decays and delays that are critical to recreating acoustic space are denser, and the perception of higher resolution allows for a more open and naturally relaxed sound that is not dynamically constricted.