Hi everyone,
I bought the Topping MX5 right after @rbq commented, as my speakers are insensitive and are in a far-field setup. The unit arrived later that day, and I've been using it daily since then (one week).
TL;DR: I really love the Topping MX5 so far, and the noise isn't an issue for me.
Noise
Let's start with the major point of discussion, the high-frequency noise. I was really worried about this because my ears are very sensitive, so I listen to music very quietly. (Roughly 1/4 of most people.) I actually hear high-frequency noise from a variety of electronic equipment that no one else can, and it regularly drives me nuts trying to find the source when in a new place (e.g. hotel room).
My speakers have a low sensitivity of 86 dB at 2.83 W / 1 m. When it's completely silent, the noise is loud and irritating with my ear within 1 foot of the tweeter. By 3 feet, the noise is clearly there but it's ignorable. At my listening position 8 feet away, the noise is faint. It is a bit annoying if my girlfriend is listening on headphones and my ears are wide open, but no big deal. Even then, I don't usually notice.
My girlfriend (24) has normal hearing and can't identify the noise until she's quite close. After locking onto it, she has to concentrate to hear it after about 2 feet from the tweeter. Overall the noise pales in comparison to the periodic noises caused by other things in the home. I guess it may be worse if your speakers are close together so that you can hear the noise from both at once.
Recall that the high-frequency noise is only present when the output is set to headphones only. Listening to audio through headphones, especially closed-back and especially at a significant volume, drowns out noise. If your speakers are not very sensitive or are not in a near-field setup, it will be less of a problem. And of course if your high-frequency hearing is not the greatest, that will help you too. Personally, I'm not bothered.
Sound
To keep it brief for now, the Topping MX5 sounds amazing. It's much clearer than my previous unit and doesn't distort at higher volumes. It's easily able to power my inefficient speakers at my girlfriend's loud volumes with plenty of headroom. The headphone out is very powerful; our Sennheisers reach adequate volume at low levels.
Where this unit really shines for me is with IEMs. With the venerable Apple dongle, I generally don't have a usable volume range unless I use my IEMatch. (Remember, I have very sensitive ears.) The MX5 gives me all the volume range I could desire with excellent sound quality. I only have insensitive IEMs now, so I can't properly judge the noise difference.
Build etc
It's too early for me to give a full review, but overall I really love this device. Somehow it seems smaller than I expected, despite knowing the measurements. It's very simple to use and all features work flawlessly as expected. There are a lot of nice touches, like the auto-off display, that make it a pleasure to use. The build is very nice as well, and I do actually like the button, although I just use the remote. It does everything I want it to with high quality and no fuss, and I can hand the remote to others with minimal instruction. For the price, I think it's a no-brainer.
I bought the Topping MX5 right after @rbq commented, as my speakers are insensitive and are in a far-field setup. The unit arrived later that day, and I've been using it daily since then (one week).
TL;DR: I really love the Topping MX5 so far, and the noise isn't an issue for me.
Noise
Let's start with the major point of discussion, the high-frequency noise. I was really worried about this because my ears are very sensitive, so I listen to music very quietly. (Roughly 1/4 of most people.) I actually hear high-frequency noise from a variety of electronic equipment that no one else can, and it regularly drives me nuts trying to find the source when in a new place (e.g. hotel room).
My speakers have a low sensitivity of 86 dB at 2.83 W / 1 m. When it's completely silent, the noise is loud and irritating with my ear within 1 foot of the tweeter. By 3 feet, the noise is clearly there but it's ignorable. At my listening position 8 feet away, the noise is faint. It is a bit annoying if my girlfriend is listening on headphones and my ears are wide open, but no big deal. Even then, I don't usually notice.
My girlfriend (24) has normal hearing and can't identify the noise until she's quite close. After locking onto it, she has to concentrate to hear it after about 2 feet from the tweeter. Overall the noise pales in comparison to the periodic noises caused by other things in the home. I guess it may be worse if your speakers are close together so that you can hear the noise from both at once.
Recall that the high-frequency noise is only present when the output is set to headphones only. Listening to audio through headphones, especially closed-back and especially at a significant volume, drowns out noise. If your speakers are not very sensitive or are not in a near-field setup, it will be less of a problem. And of course if your high-frequency hearing is not the greatest, that will help you too. Personally, I'm not bothered.
Sound
To keep it brief for now, the Topping MX5 sounds amazing. It's much clearer than my previous unit and doesn't distort at higher volumes. It's easily able to power my inefficient speakers at my girlfriend's loud volumes with plenty of headroom. The headphone out is very powerful; our Sennheisers reach adequate volume at low levels.
Where this unit really shines for me is with IEMs. With the venerable Apple dongle, I generally don't have a usable volume range unless I use my IEMatch. (Remember, I have very sensitive ears.) The MX5 gives me all the volume range I could desire with excellent sound quality. I only have insensitive IEMs now, so I can't properly judge the noise difference.
Build etc
It's too early for me to give a full review, but overall I really love this device. Somehow it seems smaller than I expected, despite knowing the measurements. It's very simple to use and all features work flawlessly as expected. There are a lot of nice touches, like the auto-off display, that make it a pleasure to use. The build is very nice as well, and I do actually like the button, although I just use the remote. It does everything I want it to with high quality and no fuss, and I can hand the remote to others with minimal instruction. For the price, I think it's a no-brainer.