Relativity. Red Fun played it like a Kinki lite version: similar tonality and sunny dry textures, just less thereof. The biggest offsets were scale, gravitas and dynamics. As it should have for the extra coin, the Chinese deck's bigger engine pulled stronger and farther whenever dynamic flickers or mega swings put their foot on the gas. This more aspirated behaviour of tossing up the taller waves scaled up music's ebb and flow for more tidal difference, more life, power and grandeur. By contrast, Fun acted tamer, more compact and contained. The same applied to soundstaging. The costlier machine did it wider and grander. But focusing purely on the color palette and tactile feel, it was very similar terrain, just a bit shrunk and compressed as though viewed from a greater distance. Hence Kinki lite. Given how the Chinese is my favourite sub €1'000 headphone amp, that was high praise indeed.

Next I downsized the Soundaware/COS front-end combo which had been deliberately price insensitive to Fun's natural playground. A more likely source was Soundaware's small Esther portable to represent  the DAP breed. Versus the separates, I noticed a similar stepping down/back as I had with the Kinki ⇒ Burson swaps, just to a far smaller degree. Source quality matters. With Esther a premium little deck, this delta of difference was simply minor. Using its line-out, medium gain sounded more transparent and quick than high. High gain piled on too much mass to get a bit opaque. In this scenario, a Zu 3.5mm stereo to twin RCA cable played analog signal transporter.

With Fun aimed at not just listeners but also gamers—remember those mic i/o and Burson's promise to maximize the sonics of your PC sound card—a laptop is Fun's native habitat. I thus borrowed Ivette's Macbook and fed it select SD card .aiff tracks via the same Zu cable. Phones were my favourite budgetarians, Meze's Neo Classic. Jacked directly into the Mac, they behaved as expected: uncomplicated, fulsome, warm, robust, with medium resolution but perfectly enjoyable. But regardless where I set Apple's digital volume, Fun was a miss/mess. It sounded as though under water or in a vast echo chamber: phasey, opaque and extremely swimmy. Checking with Burson, "your 3.5mm aux-to-RCA cable is incompatible with your laptop's output which is also a mic input whereas the jack on your cable is purely for stereo audio. You'll want to use an aux-aux cable with the Fun's frontal aux input." Mystery solved. Tapping a laptop's 3.5mm port not with a 'phone never was my bailiwick before. I needed a lesson in proper etiquette.

Another surprise had occurred with the earlier setup. From one track to the next, Fun suddenly shrieked with solid white noise at very high levels. Hitting 'pause' and 'track back' got the music back. I'd only once prior met this particular misbehaviour with a Crayon integrated during a movie session with our Oppo BluRay deck. That amp too runs an SMPS, albeit integral. I'd never learnt cause then nor was I any wiser now. As another one-off, it filed away as uhm – unexplained hifi mystery. Time to revisit the laptop with a proper cable. That after all is what Fun was designed to do: act as your external sound card. But I'm no gamer. To rustle up sound effects and dialogue, I'd do video with Apple's external DVD drive. For music, I'd stick to SD card.

For simple dialogue banter without complex location ambiance, off-boarding video sound didn't yet hit hard. If all you you do is listen to CNN/BBC news broadcasts, fly a laptop solo. It's plenty sufficient. Liewise for compressed YouTube feeds. But have proper 16-bit 44.1k/48kHz complexity scale up to carefully layered cues behind the scenes; dialogue shift into full-throttle song as it does with Empire and Nashville; action heat up with those blood-thirsty Vikings – that's when all the extra headroom, resolution and aural materialism of Burson's Fun argue loudly for additional hardware. And that's well before we thicken this stew with sheer greed by reaching for headphones far outside Fun's price neighborhood. That could be a Sennheiser HD800, Beyerdynamic T1 or Audeze LCD-CX; a HifiMan HE-1000, Meze Empyrean, Final Sonorous VIII or X… serious big-time stuff you'd not directly strap to even a premium MacBook's 3.5mm port.

At which point of polishing up your headfi ambitions you'd feel inclined to convert the above still portable audio/video setup into an exclusively stationary audio-only rig I couldn't predict. The point which Burson's Fun makes is that regardless, you won't feel the need to allocate anywhere near as much on headfi drive as you might have suspected. In fact, the next logical step up isn't a bigger amp at all. It's Burson's Swing DAC from the same range already booked for review with Frederic Beudot. That high-spec converter would tap our MacBook via USB to bypass Apple's analog output stage. And at the end of the day, that was the remaining weakness of my laptop sessions. For pure audio, I preferred the dedicated line-out of our Questyle and Soundaware portable players; or best of all, that of a proper stationary DAC like our COS.

Wrap. In essence, Fun with one of Burson's own opamps is a $399 Conductor V2 with SMPS in a cheap case. If it duplicates how the COS Engineering H2 and D1 differ—same conversion and output stage, one with linear power supply, the other with switcher—then Conductor will be weightier, warmer and denser, Fun quicker, leaner and more lit up. Either way, it's a high-value proposition with the additional attraction of socketed opamps for convenient rolling. Swapping opamps tweaks sonics to taste. Your taste. Meanwhile Burson's proven class A output stage with two pairs of complimentary transistors per side has never been this within reach before. More of your headfi funds can now apply to better headphones. That mirrors speaker-fi logic where the bigger part of the budget buys the best transducers you can afford. With Burson's Fun, $399 properly drive headphones priced beyond ten times higher. Really and truly. Now the world of headfi is your oyster. Eat up and don't be shy!