EPOS | Sennheiser GSX 300 External Gaming Sound Card Review

Photo taken by the author.

Back in 2018, Sennheiser quietly shed their entire gaming division to their long-time external partner Demant, who had been silently designing all of Sennheiser’s headset products. I was shocked at this. Gaming and bluetooth are huge growth sectors in audio right now, and while Sennheiser couldn’t have seen 2020’s work-from-home virus saga coming, it’s still wild to me that they got out of headsets altogether while others are seeing explosive sales growth.

Not only did EPOS get the rights to all of Sennheiser’s existing gaming headsets they had helped design, they also received license to use the brand name in marketing those older products until the EPOS brand can be better established going forward. That’s why this gaming headset amplifier has such an awkward name with two companies in front of it.

Unfortunately, in spite of amazing top-tier sonic performance, the awkwardness doesn’t stop with the name.

I bought this amplifier with my own funds. I don’t receive a kickback if you decide to buy one, and none of the links in this article are affiliate links. I wasn’t sponsored to write this, and I had full editorial control over this article.

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Photo taken by the author.

The EPOS | Sennheiser GSX 300 is a $79 USB-powered gaming headset amplifier and DAC designed for use with Windows(official site here). It is the first brand new product in the lineup released after the EPOS switch-over, and first went on sale in 2020. It comes in both black and “Snow Edition” white colors, and receives regular small discounts across online retail partners. I bought mine for about $71 from Amazon.

Unlike some other PC desktop amplifiers, the GSX 300 is explicitly built around powering gaming headsets, with a strange commitment to a dual jack connection. Separate mic and headphone plugs are still somewhat common on desktop PC motherboards, but single jack 4-pole 3.5mm connections have risen to prominence in the console and laptop space. As a result, most gaming headsets now ship with this single plug connection type as a standard, though they do occasionally throw a free dual-plug splitter adapter in the box.

That means that in order to use the GSX 300 with your current headset, you’ll need to make sure you have one of those splitters to allow for two connections. While the manual states that you can plug a 4-pole plug into the headset port…you won’t actually get any mic audio when you do this. This is baffling for a product released just a year ago. The SoundBlaster X G5, a much older amp I’ve owned for years, allows users to choose between a 4-pole single connection or a dual jack solution, and I would have loved to see that here.

This manual isn’t *technically* lying, but a single jack connection provides no mic support. Or if it’s supposed to, it’s broken on my unit/permanently glitched in the software. Photo taken by the author.

The brazen insistence on a slightly outdated connection method isn’t the only odd thing about the design here. While the amp has plenty of power for most gaming products, it isn’t explicitly rated for studio headphones, so if you’re looking to power your high- end pair and use a different mic you’re better off with a beefier product that has more connection choices.

Further, all of the connections for the GSX 300 are on the back of the unit. While this makes it look nice on my desk, this is also counter to nearly every other desktop consumer headphone amp I’ve used, and could make cable-routing quite difficult depending on your setup. The included USB cable features the Sennheiser logo, but it’s only 1.2m long, so if your computer isn’t right near your desk you may need a longer one. It also doesn’t use the newer USB-C connection type, yet another example of ancient design practices.

The knob on the front of the amp is a digital control tied directly to your Windows volume, so there’s no small analogue adjustments or smooth knob feel to enjoy here. It’s surrounded by a bright LED ring that shines bright blue for stereo and red for surround mode. There’s no way to turn this ring off or change the colors, so I hope you like looking at it. The small button next to the knob can be assigned to either toggle the surround mode or toggle between settings profiles in the EPOS software.

The software is nice, but all of the features are tied to it. Screenshot taken by the author.

You are required to run the EPOS software in order to get all the functions of the amp to work. It’s only designed for Windows, and leaves console and Mac users out in the cold. Inside the software is a nice EQ mode, some mic EQ and side tone options, and a toggle to re-task the front button. Unfortunately, I’ve had consistent issues with the software over the last week of testing. Sometimes it works fine, and other times it seems reluctant to actually apply my settings.

The mic input is nice, especially with the “warm” setting turned on, but the gain control isn’t as wide-ranging as I’d like, and the side tone function will only turn on if the amp thinks that you’re using communications software. So while chatting with a friend on Steam, I had side tone, but when trying to record some sample audio in Audacity, it wouldn’t let me hear myself. This “smart” functionality plagues the playback side sometimes as well. The amp constantly tries to turn off the audio signal chain in an apparent effort to save power, so when your audio starts and stops you might hear a small pop as the power state changes.

The Sennheiser-branded USB cable is nice, but might not be long enough for your setup. Also, it’s micro USB instead of USB-C. Photo taken by the author.

Once you get past this vast pile of design and software issues, you’re rewarded with tragically beautiful audio performance. I say tragic, because I so wish the surrounding package was better. Stereo rendering is immaculate, with precise neutral audio that has no detectable noise floor, and 24-bit/96khz hi-res support. And the surround mode is completely awesome, with very natural and effective speaker placement. I usually turn down the room reverb on virtual surround modes if I have the option, but this was one of the few times I found myself turning it up.

The surround effect is tremendously convincing and can stand proudly against any other current solution, although it doesn’t have the vertical channel support of Windows Sonic…which PC gamers can turn on for free. At least, if you’re using any amp solution other than the GSX 300. Since the amp maintains hardware control over sampling rates depending on the listening mode, and the Windows Spatial Audio system needs control over that setting in order to kick in, the GSX 300 isn’t compatible with either Sonic or Atmos. Both options were grayed out in my audio settings.

This page allows you to monitor your mic input…when the mic input decides to turn on. Screenshot taken by the author.

Compared against the other handful of comparably-priced DACs in my house (Schiit Fulla 2, SoundBlaster E1, SoundBlaster G5, Astro Mixamp), the EPOS model is probably my favorite in terms of raw audio output, by a hair. I tested it with a number of headsets, including an EPOS | Sennheiser GSP 300 which “conveniently” has a default dual-jack connection (review of that here) and they all sounded delightful.

But again, all this breathtaking sound comes alongside an insistence that you use two jacks which are buried on the back of the unit, and that you look at a bright light during use which might ruin your current RGB profile, and that you don’t mind small pops when audio stops and starts, and that you don’t mind not always having side tone when you want it, and that you put up with slightly janky software.

The amp’s design is more than large enough that it could have supported front-facing jacks, and allowed for a flexible headphone jack that supported 4-pole plugs without an adapter. The software could easily allow users to toggle the LED on and off. And the unit could just stay active and powered all the time, allowing side tone and audio to come through whenever users please and not when “smartly” detected.

The rear-facing dual connection jacks feel built to accommodate users of EPOS gear and slightly frustrate everyone else. And their awkward placement is textbook form-over-function. Photo taken by the author.

Without all of these issues, there’s still $80 worth of audio performance in this box…but that’s if you consider it in a vacuum. For that same $80, you could buy the JBL Quantum 300 and also get a USB dongle with incredible surround sound, which comes alongside an entire headset. For a little bit more, you could get the Roccat Elo 7.1 AIR, which matches the GSX 300 feature-for-feature, and is also an entire wireless PC headset, with customizable RGB lighting. Both have robust audio that might not quite match the clean splendor of the GSX 300’s signal, but I’d wager most gamers will still be happy.

I could write these comparisons all day. In 2021, I don’t really know who this is for. There are so many other gaming headset products now that offer you more features for less money. I get that PC gaming is sometimes about chasing that last 5 or 10 percent of performance at any cost. If you’re that sort of person, and you already have a wired gaming headset that you love, and your motherboard audio isn’t doing it for you, and you think you can put up with the design issues here…then I guess go ahead and buy it?

Everyone else that isn’t a weird collector/hobbyist like me can skip this one. I love the way that this amp sounds, and I love its surround mode. But it doesn’t sound tremendously better than any other clean ~$99 dedicated PC amp, it doesn’t support Windows Spatial Audio or consoles, and every other choice at this price point has fewer design problems.



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Alex Rowe

Alex Rowe

I write independent game reviews and commentary. Please support me directly if you enjoy my work: https://xander51.medium.com/membership