First look: SuperStereo SC78 4 channel audio interface


UK-based boutique mixer company SuperStereo turned heads at BPM 2015 with their lovely little retro-styled two-channel mixer, the DN78. Not only does it look cool with its Bakelite knobs and glowing amplification valves, it packs a lot of features and is a lot of fun to play on.

We’ve been promised a four-channel version for a while, but while we wait, the company’s next product is a lovely looking DJ-focused USB audio interface, the SC78. With just four outputs, the unit aims to do it simple, but do it well. Like the mixer, the SC78 features a pair of valves that give off a soft glow when they’re warmed up.

Both stereo channels have an independent volume control on the front, with an analogue VU meter on each to monitor output. The 6.35mm headphone socket not only has its own volume control and source-select button, it also has its own dedicated amplifier. You could almost use this unit as a mixer in itself!

Everything on the unit is given retro styling, from the knobs, to the wooden panelling, to the switches, yet this is designed as a modern piece of equipment with high quality components and, like it’s mixer cousin, a labour of love.

We were hoping to do a full review, but since the unit we got sent was a late pre-production version rather than retail hardware, you’ll have to wait a little bit to read our final say. Barring a few little details, it’s as close to what you’ll be able to buy. The biggest different visually, is the slightly wonky volume knob. Internal components were moved a few millimetres after the faceplate was drilled. It’s a small window into how this hardware is manufactured.

An insight into how hardware design changes, even just before release. You won’t be seeing this on the release model. (Well hopefully not – Ed)

First impressions


What I got sent was the basics to get it all set up. The box literally had the SC78 and separate PSU cozied up in bubble wrap. The audio interface needs the power adaptor… there’s no USB bus power option here. I would guess this is to provide reliable power for the valve stage, as well as ensure current is managed properly.

Even with this test unit, it’s got the great build quality you’d expect from a boutique hardware manufacturer. Duncan, the owner and engineer at SuperStereo, warned that there were a couple of issues and some problems with the build quality of the case that wouldn’t be on the final models. Yet it all already feels solid and looks great.

Everything from the PSU to the connectors and knobs feel durable, and the wood panelling should add an extra layer of protection from knocks and scratches. If you’re going to be throwing this in your gig bag every few days, I have no doubt it’ll hold up. And don’t worry about the valves breaking. These bad boys are guaranteed against breakage from accidental drops. We’re talking military spec, here.


The SC78 features similar VU meters to the mixer and they’re just as cool, taking me back to the early 80s, sat in my parents’ living room with their brushed-steel SONY hi-fi separates system, watching the needles dancing while a Bruce Springsteen record played. The VU meters have been given extra headroom, so that they’re more just for indication of sound levels, rather than finer volume monitoring.


The controls for the headphones make the SC78 useful for listening at your desk, but the channel RCAs mean connectivity to monitor speakers would be a bit of a fudge. You’re going to have to compromise on cables by going from RCA to (likely) TS/XLR. It’s definitely not the end of the world, but this is meant to be a DJ audio interface through and through.

There are several LEDs on the front of the case, but none are frivolous: they all have their use. The ‘Valves’ LED lights up when you turn the unit on until the valves are warmed up, then turns off to show it’s ready to use. This process only takes a couple of minutes maximum. The ‘Lock’ light is a nice little feature that displays what sample rate the interface is set to: blue for 44.1 kHz, green for 48 kHz, turquoise for 88.2 kHz, red for 96 kHz, orange for 176.4 kHz, and purple for 192 kHz. I’m not actually aware of any other DJ product that does this, so it’s a pretty cool ‘at-a-glance’ feature. Both the ‘USB’ and “Power’ LEDs are self-explanatory.

If you’re a macOS user, one thing to always look out for is whether audio hardware is USB class compliant. If it isn’t, Mac users probably need to install drivers and software (much like with early Native Instruments hardware) which seems to be a contributing factor in OS updates causing obsolescence. I’m happy to say that the SC78 is fully USB class compliant and doesn’t need any special drivers or software. You still need ASIO drivers for Windows, though.

But how does it sound?


I really hate writing ‘audio quality’ sections of reviews and previews. All I can offer is an opinion and look at the facts. I don’t claim to be an expert, but I do trust my ears. The thing about hardware at this level of quality is that, barring technical problems, it’s always going to sound great. How ‘great’ depends on how important a feature it is to you.

That said, on paper, there’s some nice kit in the SC78. Every stage of the audio signal has been considered. The only (slight) downer is that the digital/analogue converter (DAC) “only” goes to 192 kHz sample rate. I say “only” because that’s still going to be plenty for DJs, yet the DN78 can do 384 kHz. I suspect that SuperStereo realised that sort of sample rate was just overkill in DJ gear when there will mostly be 320kbps MP3s running through it.

NOTE: Duncan let us know that the SC-78 actually uses the same audio chip, just capped at 192 kHz. If you use stereo mode by unticking quadrophonic in the sound settings, you can go higher.

A lot of people would argue that in the digital age, using valve amplification isn’t necessary. But there’s a reason why so many still love the effect. What isn’t in dispute is that valves do contribute to the tone of audio run through it, and just like with their rotary mixer, the valves inject a bit of warmth and fun into the music.

The short time I had to DJ with the audio interface, I was quite happy with how it handled my range of music genres. Latency can be kept low, and on my MacBook Pro 2015, it was perfectly happy running at 96 kHz sample rate. Once I’d gotten the output volumes set up right, the valves glowed happily, and the sound felt as warm as the DN78 mixer.

The front panel features a couple of 3.5mm mini-jack inputs so you can run external sources through the valves. If you’ve got some tunes on your phone, or even something like a sampler/synthesiser, they can plug in as a sort of AUX for each stereo channel, which is a nice touch.

Thinking ahead

My time with the SC78 showed me that it’s pretty obvious a DVS-focused version is needed, and would be an attractive product for the market that might be keen on what SuperStereo aims to create. The opportunity to run turntables through all this high-spec hardware is a delicious prospect. I myself am a fan of using separate audio interfaces and mixers, as I’ve been upfront about in the past. With that said, a little bird told me that there may be a companion product to bridge the gap for turntable users on the horizon. Watch this space.

Beyond this, it also makes sense to have a eight (or even 10) channel version for those of us that need more than two decks. Also, a producer version with balanced outputs, and inputs for microphone would make for an intriguing product. It might be nice to have several valves with selectable input and output switches.

As for the SC78, the only change I’d suggest (from a usability perspective) would be swapping the headphone volume knob and jack input to make changing headphone volume a bit easier. As it stands, when the interface is sat on a flat surface, plugged-in headphones make access to the volume knob a bit fiddly. Aesthetically, it would be less pleasing, but much easier to use.

Having spent a week or so with the SC78, I have much love for what SuperStereo are doing, and I get the feeling they’re quite happy with their place as a niche company, making a relatively small group of fans very happy. I look at their products and think “digital brain, analogue heart”, which is pretty much the best of both worlds.

The SuperStereo SC78 four-channel USB audio interface is available for preorder right now, costing £595 for EU customers, and £505 for non-EU. Current waiting time is between three to four weeks. There will also be a foam-lined carry-case available for £15.