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"The BPS-02 has two internal battery packs controlled by an analog 'flip-flop' logic. It's quite complicated actually and probably why nobody has been able to develop one before. Hence also our patent-pending status. There is no 'drop-out' because at the transition period of less than one second, the logic circuit simply connects both batteries together (one low, one high capacity). They get momentarily paralleled and two packs become one. But there's more to the internal circuitry. To lower output impedance we employ ultra-low impedance capacitors both at the input and output stages of the BPS-02, not to mention that its PCB design ensures separate grounds between the input, output and logic sections and is manufactured in gold-plated 2-ounce copper traces." - Soo In

KingRex uArt USB Y cable
While I felt certain that he smiled enigmatically while typing that answer, I'd gotten more than expected. Time to contribute my part. First to the basic concept. Many USB transceivers are powered by 5V computer power. This opens the floodgates of switch-mode and ultra-fast processor noise into your D/A converter. Audio and computer grounds simply shouldn't shake hands. Even so they often do, never mind Kipling's never the twain shall meet. Enter the battery-powered USB cable. Unlike wall-wart powered devices whose voltage may or may not match, USB-powered devices all conform to the 5V standard. Any battery supply which outputs 5V can play interceptor. [The popular HiFace Two with XMOS transceiver, dual clocks and pulse transformer on the coax output is one obvious candidate and Aussie vendor Elijah Audio makes a special $105 cable for that application.]
Elijah Audio BMP cable connecting hiFace Two to a generic battery supply.

Aside from such a battery supply you'll also need a split or 'reverse biwire' USB cable like KingRex and others make. This separates the two power conductors from the two signal conductors and terminates in two parallel USB ends on the computer side. And that's how USB bus power gets shafted and battery power takes over. It's not a coup d'état but coup d'électrique. It upgrades your USB transceiver from dirty computer power to its very own dedicated pristine battery supply. Obviously with any USB transceiver that's powered from its DAC's internal power supply, this whole scheme won't work. But neither is it required in the first place. Then spend your upgrade money on something else. In my case the Eximus DP1's XMOS transceiver is bus-powered. So is the outboard Audiophilleo at left. Hence my desire to get the purest power to these trusty audio workers.

The Bakoon's tidy extrusion smaller than a jewel case contains an L-shaped main board to clear the sleeved batteries; and a small 'second storey' board (the next production run will go to a square board and mount the batteries atop it for quicker assembly/disassembly as shown on the previous page). The batteries on my unit were secured with a foam glue strip to stay put. The SMPS charger has a green/red LED to confirm operation and status. The frontal LEDs light up white or yellow depending on which battery is active. During the transition period they both fire but due to color strength you'll likely see mostly white (if you happen to look at just the right second). When the power switch turns off, the batteries connect in parallel and the recharger charges both until they reach full capacity. "One needn't ever disconnect the charger. It disconnects itself when the batteries are fully charged and the LED on the charger turns green. This automatically gives the batteries 'a break'. The design concept of the BPS-02 was full user convenience without considering anything about charging, discharging, disconnecting etc. We provide simple clean battery power free of any noise from both internal and external environments."

The BPS-02 back has two ports. The inner is for the charger, the outer serves as DC umbilical feed which in my case was set at 5V and terminated with the requested USB connector. Certain USB cables can be very stiff to resist twisting in just the right orientation. Bakoon's pigtail solves any such issues. You can turn and twist it any which way you need. It also liberates the company from having to fit different output connectors to the box. One size fits all, the umbilical termination sorts out the customization requirements.

Sonix. How much could a smart battery do for USB? If you've loved the Taksim Trio to be impatient for an encore, reach for Soundscapes by The Secret Trio. It unites Ara Dinkjian, Tamer Pinabasi and Ismail Lumanovski for a very similar oud, qanun and clarinet ensemble. The go-batty effects will appear in the level of contrast between players on tone colors and firmness of focus. There'll be purer fuller string attacks without twangy sheen. The zither's rain-drop accompaniment will have finer articulation with some subliminal haze removed. This is about subtleties easily heard, not as easily described. The overall feel gets more fluid, the gestalt more organic as though some level of electronic glare had vanished. Some sharpness relaxes. Rather than dilute the mix, it becomes finer and freer. Space opens up. Compared to the KingRex, the Bakoon did more; nothing fundamentally different, just more.

On José Antonio Rodriguez's Anartista, polished Spanish flamenco guitar meets many collaborators. Portuguese fadista Mafalda Arnauth is one of them. Moving the uArt's power lead between iMac and Bakoon showed the same effects. Off the iMac the glinty trills in a lead-guitar melody were grainier, its rapid staccato runs brighter. The BPS-02 read was easier. That's obviously a listener reaction too but no more imaginary than two perfectly sharp kitchen knifes with one better balanced to (have you) work better. Listening intently is a form of work. We tend to underestimate the benefits which stress reduction has on the experience. All forms of electronic noise are reminders of artifice we have to deliberately overlook even if we don't do it consciously. Less noise means less work. And that sounds better even if it's impossible to point your finger directly at all of the why.

Far from all battery effects are 'vague' but it's fair to mention those too. They contribute but likely aren't obvious in quick A/B shootouts. They're best tracked having settled into this more relaxed state of mind for some time before one switches back to computer power. Aside from the sonically qualifiable attributes something slightly nervous and jittery will reassert itself. And that's best appreciated by sudden addition rather than subjectively gradual subtraction as we slowly release tensions because everything sounds and flows more naturally.

At €330, Bakoon's BPS-02 is truly fantastic value. And functionally it's far higher IQ than its €750 progenitor to suggest that the son will soon kill off his dad. That's true Freudian advancement. What we need to lobby for next is a BPS-03 with twice the battery capacity to run 12V wart-ridden components like the digital-direct Cambridge Audio iD100 dock. I'd buy one for each of my two iPods sight unseen. But owners of Bel Canto Design's bus-powered USB-to-S/PDIF converters and others like them; the aforementioned DACs; even certain affordable wart-powered phono stages can get into this off-the-grid act now. To neatly sidestep the abused 'a' word, if it's about making digital more human, battery power for low-current low-level circuits would seem ideal to get us closer. I simply didn't expect that it could mean uninterruptible power. That's so trick as to call for formal enthusiasm with an award. Because both size and price are small, that's all about realsization!

Bakoon Products website