SMSL SH-9 THX AAA-888 Balanced Headphone Amplifier Review (1) – Value

Immediately following Durwood’s and my rave reviews of the SMSL SU-9 preamp/DAC, Apos Audio sent me the SMSL SH-9 unsolicited (cynically, I wonder if I would have gotten it if I had panned the SU-9). In any event, the $299 is an aesthetic twin of the SU-9, with the same compact metal casing, cool blue digital display and three wobbly rubber feet (which irk reviewers more than anything else about these products). As with the SMSL SH-9, a single front knob controls volume, gain, brightness levels and input selection; as with the SH-9 the knob is very intuitive and I had no need for the included remote (which seems like a gratuitous inclusion since by definition you sit right next to the amp while listening to headphones).

I’ve been perfectly content with the $99 Schiit Magni and the $149 Pro-Ject Head Box, and I didn’t expect to blown away by the SMSL SH-9, which has neither an onboard DAC nor (more conspicuously) a preamp out. Technologically, the SH-9 is the far more advanced product, with the same much-vaunted THX AAA amp as much pricier units and a very well-executed relay volume control, which provides for  much finer control and better channel balance than conventional volume pots. In contrast to its cheaper rivals, noise floor and distortion are, as advertised, inaudible; I heard no hiss even on very sensitive phones. I tested the SMSL SH-9 with phones ranging from 16 ohm to 250 ohm and found its power to be adequate, not overwhelming; for whatever reason I found the low-gain setting to be more anemic than the specs would suggest and that even my more sensitive phones sounded fuller and better in high-gain. You do notice, however, that the amp runs very warm, which could be an issue in poorly ventilated racks.

As with the SU-9 DAC, the SMSL SH-9 has a distinctive sonic character—energetic and slightly smooth, with a boosted midrange presence. The overall effect is to sweeten the high end and to substantially tighten the bass—my new Aune Jasper (reviewed here) sounded more impactful and detailed with the SMSL SH-9 than with my USB-powered portable dac/amps, while even a cheap piece like the Koss Portapro or Aiaiai Tracks on-ears took on a fuller sound, with much punchier low end. The  Schiit and Pro-Ject amps, by way of comparison, are more transparent and less colored—they’re closer to the “wire with gain” approach and don’t change the character of the headphone’s signature to the same extent. The ($549) Chord Mojo, at least from memory, also sounded truer-to-source, though depending upon the quality of the recording not necessarily better.

At the end of the day, I had no material qualms with the SMSL SH-9’s performance. As a value proposition, it has much of the topography and features of (and likely measures as well as) exponentially more expensive mainstream gear. Its visual symmetry with the superb SMSL SU-9 DAC is another obvious selling point. For whatever reason, I still question whether my aging ears can fully appreciate the differences between the SH-9 and cheaper-but-still functional amps, and viscerally I didn’t have the gotta-buy-it sensation that I did with the SMSL SU-9 DAC. However, more discerning listeners will find much to appreciate here, and there’s no doubt SMSL knows what it’s doing.

Disclaimer: Apos loaned me this unit for review; it will be passed on to my colleagues before being returned to Apos. Tested at $289.

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