SMSL DO100 PRO Review: A $219 DAC With a Tinkerer's Switch

Pick #5 of 8 in our Best DACs guide.

DACs play a critical role in delivering high-quality sound in any audio system that isn't purely analog. Digital-to-analog converters bridge the gap between the digital world of your music files and the analog world of sound waves our ears perceive. By converting digital data into analog signals, DACs directly influence the overall quality and character of the audio you experience.

The SMSL DO100 PRO is a new option in the lower-mid-range price segment.

An aluminum build and a slightly wobbly knob

Is it built like a tank? No, but you wouldn't expect it to be for a bit over $200. Is it constructed poorly then? Nope, not that either.

Pick it up and you might be surprised. On one hand, it feels quite lightweight despite clocking in at nearly 1.5 kg (over 3 pounds). On the other hand, it features a full aluminum body - not the thickest one, but it's miles ahead of being made of plastic.

The bottom is supported by 4 tall rubber feet, which can be upgraded if needed, as they're held down by screws. They do a decent job - the unit doesn't slide very easily on the desk.

The top has a Hi-Res Audio Wireless sticker, which is a nice addition, but it doesn't mean anything useful for the actual audio quality as far as I'm aware.

The DO100 PRO features a front screen that can display lots of useful information, like the current sampling rate, the input you're using, the high-frequency digital filter, brightness, and the DPLL value (more on which later). A retro-style knob located on the right side is plastic, with some wobble - but that's not a very big issue, as it's fully digitally stepped with a distinct tactile feel. It lets you go through all the options and set them up how you want them.

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On the back, you'll find all the I/O: an AC input with a power switch, USB-C for digital connections, a Bluetooth antenna port for wireless audio streaming, HDMI ARC, Optical Toslink, and Coaxial. For the analog outputs, there are single-ended RCA and balanced XLR outputs. It's worth noting that the DO100 PRO is a balanced DAC internally, and I noticed a slight improvement in sound quality when utilizing the balanced XLR outputs.

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Features from dual ESS chips to DPLL control

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Now, onto the features - there's a lot. At its core sit two new-generation high-end ESS DAC chips, working together with six high-end OPA1612 dual op-amps, fed by a brand-new third-generation XMOS chip that supports up to PCM 32-bit/768kHz and DSD512. It'll happily decode DSD as well as DoP64, and it even handles the most controversial formats on Earth - MQA and MQA-CD - which is nice to have whether or not you ever end up using them. On the connectivity and convenience side you get two selectable USB modes, 1.1 and 2.0, depending on the device you're hooking up to, plus a Japan Audio Association Hi-Res certification, a choice of multiple digital filters, and a lightweight remote that does its job just fine.

The ESS chips feature a DPLL value control, a special function typically not exposed to the end user. This function allows you to select a value between 1 and 9, based on the clock jitter and accuracy. If the clock stability is high, you can decrease this value to improve system performance and achieve slightly superior sound quality. On the other hand, increasing the value would be beneficial if you encounter a significant amount of clock jitter leading to audio artifacts such as digital noise and pops.

The maximum supported PCM sampling rate is 768kHz at a 32-bit dynamic range, which is close to the highest possible PCM resolution you can achieve. This leaves you with a lot of room for upsampling using software like HQPlayer or PGGB.

That's a lot of functions for a DAC in this price category. But how does it sound?

A solid sound, slightly analytical and soft

First of all, it's solid - really solid. There are no sonic issues with it that could be bothersome. It leans slightly to an analytical side of tonality, likely due to the ESS DAC chips used inside. However, it's not sharp or unpleasant, and if you don't like the ever-so-slightly enhanced top-end presentation, you can use a faster and more aggressive filter.

For systems that are neutral or slightly lacking in treble detail, the DO100 PRO is unlikely to push things into excessively bright territory. In these cases, it could potentially enhance clarity, detail, and definition without introducing harshness. Besides that, the tonal presentation is mostly neutral, without any added warmth or bass energy.

Resolution-wise, it's a bit above average. I'd say it can resolve details fairly well on a macro scale, as you'd expect for a modern DAC, and it does just fine on a micro scale. Unless your expectations are sky-high, you won't be disappointed.

The soundstage presentation isn't huge, but it doesn't collapse in any of the dimensions. Width is there, depth is there, and height is also there - but to a lesser extent. Of course, it does not sound HUGE like top-of-the-line DACs that cost multiple times more, but it is definitely not collapsing the sound and making it tiny.

Let's talk dynamics. It's not room-shaking, not at all. But what I feel it's doing is being true to source, and capable enough for most kinds of music and gear. Generally, I felt a slight sense of softness - not particularly a lack of dynamics, but softness. That didn't bother me much, and it's already miles ahead of SMSL's lower-end products.

So in terms of the DO100 PRO, I think it's priced well. It doesn't break any world records, but it's just a good-sounding DAC for this price, which can be a decent step up from some cheaper units. It lets you have fun with lots of options, adjust them to your liking, and explore different flavors of digital audio.