I know that this is more of a DAC/speaker amp but seeing that I use this to power headphones also, I thought I would review it here. It just so happens also that Amir on ASR published measurements for this yesterday, so I have posted the functionality part of this review over there also.
I would also like to apologize for the very crappy quality of the photos in this review, I only had my phone with me and there is very little light in my bedroom. When I get chance, I will take a couple of better pics and edit this post. Excuses aside…
MY REVIEW OF THE TOPPING MX3
I purchased this unit to be placed in my bedroom, allowing me to power the speakers I have over the bed at the same time as offering me a headphone source for late night listening (or early morning, depending on how you look at it).
When looking for a DAC/Amp for this set up, I was undecisive between the SMSL AD18 and this Topping unit. While there are some differences, the fact that the MX3 stores the volume levels independently for headphones and speakers was the main function that swayed me toward the unit. I also prefer the form factor and looks, but that is a totally personal decision.
First, the specs…
POWER & OUTPUTS
As far as power specs are concerned, this is not a very powerful unit, especially for headphone use, the specs published by Topping are as follows:
Speakers
- 2x 38W at 8 Ohms, 2x 40W at 4 Ohms.
- 0.05% THD+N
- 92dB SNR at 8Ohms, 91dB SNR at 4 Ohms.
- Gain 29.6dB
Headphones
- 257mW
- 103dB SNR
- 0.005% THD+N at 32 Ohms 130mW
- Gain 11.6dB
- Recommended Headphone Impedance 16-300 Ohms
- Frequency Response 20Hz to 200kHz
All of the above specs are based on using the AUX (analog) input.
On the Audiophonics page there are different specs listed, however, the above are those listed in the Topping MX3 manual.
I do not have any instrumentation here to be able to test the actual power of the outputs, but if we look at the speaker power specs, I find it very strange that there would only be a 5% difference in power between running at 4 Ohm and 8 Ohm.
The outputs for the speakers are the typical binding posts that accept a banana plug if you prefer, although they are gold plated (or at least it looks like it). There is also a dedicated subwoofer output for adding a powered subwoofer, I haven’t tested this output but from other reviews I understand that there is no crossover functionality and that the subwoofer remains active even when in headphone mode. I can’t confirm this is the case as I haven’t tested it but I can understand that this is an issue if it is true.
The headphone socket is a 3.5mm jack located on the front of the unit, the socket itself is one of the “dual blade” type rather than a normal round socket. It doesn’t look flimsy but it may prove to be so after a lot of use.
The bandwidth is shown as being “20Hz to 200kHz +/-1dB” which I am pretty sure is a typo, but I can’t argue that it doesn’t reproduce 198000Hz at +/- 1dB, at least by ear 
Closing the subject of power, the unit uses a rather large power brick (230V in my case) that outputs 3.75A at 24V to the unit. The power brick has a bright blue LED that will actually light up the room in the dark if facing upwards (we are currently using it for a night light for my 4 month old son that still sleeps in our room).
INPUTS
On the back of the unit there are the following inputs:
– 1x Analog Stereo RCA input
– 1x USB Type B (16-24bit / 44.1-96kHz)
– 1x Toslink optical input (16-24bit / 44.1-192kHz)
– 1x Coaxial input (16-24bit / 44.1-192kHz)
– Antenna for the bluetooth reception (BT 4.0)
A little bit of creative cable management
On to the unit…
OVERVIEW
In the box you get the unit itself, the power supply, a USB A to USB B cable, a small remote control (that actually includes the battery, at least in the EU) and an NFC sticker.
The MX3 measures 185mm x 122mm x 38mm (Depth/Width/Height) and weighs 475g.
I actually like the machined finish of the unit and I think it looks pretty decent (especially for its price) but again this is just a personal preference. It is also available in black but I haven’t seen it in person.
On the front of the unit you get the headphone socket mentioned above, a nice rotary encoder knob and a large amber screen that is very easy to read. The screen is dimmable and also auto-dimmable, sometimes, but more about that in a moment.
Four rubber feet are placed on the bottom with the top and sides empty. There is an NFC sticker included in the box which I believe is meant to be affixed to the top of the unit, this is supposed to tell your phone to connect to the device via bluetooth, however, I don’t have any NFC devices so I can’t confirm that.
FUNCTIONALITY
There are somethings that I really like about the Topping MX3 but there are also some quirks that annoy me.
The rotary encoder knob allows you to change volume by turning, change inputs by pressing and turn off via a long press, everything else must be done with the remote control. The manual states that the rotary knob can also be used for increasing/decreasing bass and treble, to be able to get to the bass or treble adjustment you need to first select them on the remote, which sort of defeats the object. With the remote is where the first issues arise… it is absolutely terrible!
The remote will work or not work, totally dependent on what it feels like at that moment. It seems to not want to work at all when less than 50cm from the device and definitely doesn’t work when more than 2m away. This is not actually much of an issue for me personally as I have a universal remote above the bed that controls the TV, lights, ceiling fan and now the amplifier (I just copied the commands from the original remote). However, for anyone interested in the unit, they should factor in that they will need to buy a universal remote (with learn function) if they want to enjoy all the features of the unit.
When powering on the MX3, it will automatically remember the last input you were connected to and the output you had selected with the volume level it was set to. As far as output selections, you can select between headphones only (the headphone symbol will show on screen), speakers only (the headphone symbol will disappear from the screen) or headphones and speakers simultaneously (the headphone symbol will flash on the screen). As said before, the volume levels will be remembered when switching between inputs, which avoids blasting unexpectedly through either speakers or headphones, although the volume levels are linked when in headphone and speaker combined mode. You can only select the output mode by using the remote.
To switch between inputs, you can cycle either by pressing the knob on the front of the amplifier or by pressing the “SEL” button on the remote (if the remote decides it is going to work ). This will cycle the unit through BT > USB > Optic > Coax > Aux. The screen will show which input is selected at all times. If an input that has no signal is selected, the symbol for that input will continue to flash, showing that the signal is not present, ie: if you turn the TV off while in Optical mode, the “Optic” symbol will flash. When selecting a new input, the screen will briefly show the kHz of the selected input before reverting back to show the current volume level. Note that neither of these will happen if the analog input is selected.
Adjustment of volume can be made by the rotary encoder knob on the MX3 or via the “up” and “down” buttons on the remote. The adjustment via the knob is very precise and the steps will be dependent on how fast the knob is turned. If you turn the volume knob slowly, it will increase in 1 step increments, if it is turned quickly, it will “jump” to a higher volume a lot quicker with less actual travel (great for quickly turning down the volume when needed). You can choose whether you would like the current volume displayed in a 0 to 100 scale or in a -60dB to 20dB scale. To switch between these, you need to use the remote to do so and hold the mute key while pressing the mode button.
The Bluetooth receiver of the MX3 connects very easily from Android devices (I haven’t tried other devices) and there is no confirmation code. I mention the lack of confirmation code as this means that anyone within the Bluetooth range of the device can connect to it, in other words, if you live in an apartment and your neighbor is close enough, he may decide to play music at random times, especially when in “Auto” mode (I will explain more about “Auto” in a minute). The Bluetooth range is very low, I believe it is listed at 10m, however I can confirm that if I am over 5m away, connectivity is lost.
As far as USB is concerned, I can easily connect from Windows 7 and Windows 10 laptops, also easily from my Android phone. However, for some reason, my Android tablet does not work (at least I haven’t been able to make it work) although it works fine with other Topping DACs I have. When connecting the tablet, the screen briefly flickers between 48kHz and 96kHz, then settles on 48kHz but no sound is present (the tablet does show it as connected and playing music, the tablet also works fine with other Topping DACs).
The other inputs (coax, optical and analog) function as expected.
For equalization, you can select either bass or treble using their corresponding buttons on the remote and then adjust each of these by +/- 10dB. If you change the setting on either bass or treble, you can revert the setting to 0 by a long press of the corresponding button.
AUTO FEATURE
I think the “Auto” feature deserves its own section due to the well thought out but badly executed system. The idea is that the MX3 has various things that can be set to be automatic, these are things like the auto-dimming of the screen, the auto selection of output when headphones are inserted or removed, the auto switching on and off etc.
To be totally honest, the auto switching on and off was one of the main reasons I purchased this unit (along with the storing of volumes) over the SMSL AD18. My wife, who uses this amplifier just as much as I do, is the sort of person that wants technology to be as simple as possible, if you need to press more than three buttons to get something to work then it is too complicated 
So, when I saw that the Topping could be set to automatically switch on when receiving signal from the TV 8via optical input) and switch off when the signal is lost (after 2 mins), I thought that was great, especially because my wife (when I am away) likes to set the TV to automatically turn off afte X amount of time, this would mean that amp would turn off also.
Alas, not so easy!
There is one single option on the MX3 that is “Auto” on or off. This option turns on or off all of the automatic features at the same time, these are:
- Automatically switch on when signal is detected (except Analog signal).
- Automatically switch off after 2 mins when signal is not present (except Analog signal).
- Automatically dim screen after six seconds of inactivity.
- Automatically switch to headphones when inserted and speakers when removed.
- Automatically switch to signal of highest priority
Now, as I leave headphones plugged in permanently and would also like it to turn on/off, you would think that the above would be perfect for me. However, when the unit is switched to “Auto” on, the optical signals are always active, this includes the BT receiver. When the unit is in standby, the Bluetooth receiver continues to be active and searching for a connection. When I go to bed at night, I turn off wifi, data and BT on my phone, however, when I go to work in the morning, my car is parked outside my bedroom window (less than 4m from the device) and if my phone decides that instead of connecting to my car it will connect to the MX3, which has been left in speaker mode (usually when switched off automatically it will be in speaker mode in my case), then music will start to play in the bedroom at some early hour of the morning while my wife and child may still be asleep! It also means that the MX3 can be detected at any time, even in standby, and as there is no confirmation code to connect, my neighbor could decide to play music in my bedroom at whatever time of night or day he feels like!!
This also proves to be an issue when walking into the room while my phone (or my wife’s phone) is playing music via the raspberry pi I use for multiroom streaming, or even if spotify is on pause on the phone and was the last app to be used. In this case the MX3 automatically connects to the phone and as the priority of inputs on the MX3 is BT > USB > OPT > COAX, the device automatically switches to the BT input and the phone starts playing music through the amp.
I also prefer to have as few wireless signals in my bedroom as possible while sleeping, so the BT receiver that is 30cm away from my ear is not something I am overly fond of.
If I could just disable the BT connection I would be happy but, needless to say, the “Auto” function, which was one of the selling points for me, remains off in my case.
SOUND
This is obviously the most subjective part of the review. I am a one of those people that believes an amplifier should not have its own sound, unless we are dealing with a tube amplifier. In the case of the Topping MX3, it’s aim is to be as clear as possible.
Amir, over on ASR, published the measurements for the output of this amplifier yesterday, so if you are interested in the facts, please check that out.
As far as my listening tests…
I am using this unit to power a pair of Bose Freespace DS 16 speakers that are installed above my bed. These speakers are certainly not audiophile speakers designed for faithful reproduction of music, however, these are only used at very low volumes for listening to the TV or music late at night or early in the morning. The reason they are installed above the bed is so that we can have clear sound at a reasonable volume without disturbing my other son, who’s bed is against the wall behind the TV.
The specs of these speakers are:
- 16W RMS
- 95Hz to 17kHz frequency response
- Max SPL 96dB
- Dispersion 170Âş x 160Âş
If you actually look at the speaker itself, on the rear, the SPL at 8 Ohms is actually 83dBA at 3.1m. My listening position is around 80cm from the speakers!
This means that I do not push the MX3 above around 15/100 most of the time and even during the day I will have sufficient volume before I reach the 50/100 mark.
Amir’s tests show that there is distortion when the amplifier is pushed (specifically using the digital inputs, so basically from the DAC), however, I am sure that the Bose speakers distort before there is any sign of distortion from the Topping.
At the moment, the unit is installed by my bed and I am not going to remove it to try it with other speakers. If I do get around to doing a YT review on it, I will try with other speakers and post back here with results.
For the headphone side of things, I usually just use IEMs in bed, but for testing purposed, I have used the following:
- Tin Audio T2 IEMs
- KZ ED16
- Audio Technica M40x
- Beyerdynamic DT 1990
The first three on the list run fine with no sign of distortion or muddiness, at least as high in volume as I was willing to push them.
The Beyer DT1990 were a different story. With these it is possible to push them into distortion (from the MX3) while still being inside listening volumes, that is, if you listen loudly. I haven’t yet had chance to test the HD6XX but I am sure it will be the same or worse.
I will say though, at the volumes I usually maintain with this unit (between 10 and 18 out of 100), even the DT1990 sound fine.
CONCLUSIONS
While this is definitely not going to win any prizes for being the loudest, cleanest or the most user friendly, for the price point of this device, the functions you get are amazing.
It has its quirks, some of which are very irritating, but it does serve the purpose that I bought it for. In fact, if I could just disable the Bluetooth then I would be happy.
I would certainly recommend this unit to power some speakers in a secondary position, or even as a unit to place on a desk at work, as it is quite competent for casual listening both with speakers and headphones. I would not recommend this as an only unit to someone who wants to do more in depth listening, although, at the price, there aren’t too many options that can do all this.
