This review of the SMSL HO100 will show you exactly why this is quickly becoming my favorite budget Headphone Amplifier.
HO100 Inputs and Outputs
The SMSL HO100 being reviewed is a budget friendly, no frills headphone amplifier. It is absolutely about one thing quality. And when I say no frills, I mean it. It is a classic all aluminum frame with a beautiful glass bezel but it only has your basic controls on the front panel. those include three toggle switches to switch you amplifier on off, switch between xlr and RCA inputs as well as a high mid and low gain selector. You will also have your headphone outputs (a 4.4mm for balanced output and a ¼” for unbalanced out) which should have you covered for most types of headphones that you will be using. And finally it has a volume knob on the right hand side. when you turn it around you aren’t going to see much. In fact, all you will see is the XLR balance inputs, and your unbalanced RCA along with an IEC jack for power. And they have all of this in a small compact case. In fact, the case is only 5 inches long by 6 inches wide and 1.5 inches tall and it only only weighs 1.23 pounds.
Now, although I see this is no-frills, remember I said that the SMSL HO100 is all about quality. And you start to see the attention and care they put into this amplifier as soon as you start to use it. In fact, it was very clear they didn’t cheap out on materials like many companies are doing now a days. From the first time I picked it up, you could tell this unit was solid. The all aluminum exterior was robust for its size and weight. In fact, the overall build quality is exactly what I would expect from SMSL’s higher end line, not this one. In fact it is the same fit and finish as their much more expensive HO200.
The HO100 toggle switches are nice and rigid with that think that you like to hear from good quality toggles. They have all gold finishes on the inputs and outputs and even the volume control is very smooth without any type of hesitation. Honestly, the switches and knobs feel exactly like they do on their higher end units. They did not cheap out on these and that is very nice to see. I was also surprised to see that the HO100 included a built in power supply, so no bulky power supply hanging out your desk just a simple power cord that you can plug into the wall. This makes for a much cleaner install. And thankfully, with the power supply built-in you do not have to wonder if you are going to get a noisy power adapter. Making this more likely to sound just like SMSL intended.
The HO100 also packs quite a bit of punch for its size. It can deliver three watts of power into 16 ohm headphones or one and a half wants into 32 ohm headphones. Which is going to be about half the wattage that you would see on a higher end headphone amplifier like the HO200. However, in this type of price range I think this is exactly what you should expect. And honestly in this price range you’re most likely going to be using some of the lower impedance headphones. And it is those Headphones that this type of headphone amplifier is specifically tailored for. And during my testing I didn’t have any issues driving my headphones to more than adequate levels.
It is important to note, that although it does have the fit and finish and the look of a high-end headphone amplifier, the most important thing of any headphone amplifier is its sound quality. And although I know, SMSL makes some high-quality gear I was not expecting the sound quality that I got out of the HO100. Not only did this headphone amplifier exceed my expectations on sound quality. It sounded just as good as it’s a bigger brother, the HO200 it was crisp and clear and very neutral. It didn’t add any bass or treble like some of the cheaper headphone amplifiers do. Best of all, the HO100 was absolutely silent. When I say silent, the unit itself is obviously silent as it is all solid state with no fans. So the operation of the unit itself is silent. But what I say silent I’m talking about the distortion and noise floor. The total harmonic distortion plus noise is -123 dB. That is well below human hearing! But if you want to visualize that as a percentage, it is 0.00006%. That is astronomically low! And a lot lower than I would ever expect in a headphone amplifier at this price range. And this absolutely made a huge impact when listening to music during those silent scenes. Instead of hearing a hiss or a noise that wasn’t there, I heard nothing. Silence. And that’s exactly what I want from a headphone amplifier. And I definitely as not expecting it in this price range.
Measurements of the HO100
It is one thing for me to tell you this, but it would be nice to back it up with some measurements. Unfortunately, I don’t have the access to be able to measure this myself, but one thing that SMSL does is they provide all the measurements for you. When we take a look at their measurements, we see that the frequency responses from 20 hertz all the way up to 100 kilohertz and that frequency response is completely linear and that explains why this amplifier is so great at reproducing exactly what the artist had intended.
Now it’s rather obvious that I love the sound quality and the fit and finish of the HO100. But that doesn’t mean that I love everything. There are some cons to this headphone amplifier. For example, when we look at the HO200 it’s bigger brother you’ll notice that you’re actually getting some balanced and unbalanced outputs. This allows you to hook up something like powered desktop speakers, to the back of this. Allowing you to simply toggle between your headphones, and your speakers with the flip of a switch. The less expensive alternative doesn’t have any type of outputs like that so this truly is only a headphone amplifier. And that’s not really a problem as long as you understand what you’re getting.
Final Thoughts on the SMSL HO100
Now this is probably a first for me because I don’t really have anything negative to say about this amplifier. Honestly, it blew away all of my expectations and it has become my favorite budget headphone amplifier. In fact, if you’re looking for a headphone amplifier in the $150 range I wouldn’t look any further. I just don’t see you being able to get anything better than this in that price range, but having said that if you do need some more outputs, then look at some of my other reviews where I looked at the topping and of course the SMSL HO200. Now It is time to figure out exactly where to place this on my list? I am going to place it right below the SMSLHO200. Mainly due to the fact it doesn’t have any RCA or XLR outputs and is lower wattage. However, ti has the advantage with it’s size. And if you don’t need the wattage or outputs, then I would absolutely buy the HO100 over the HO200.