Going upskirt, thinking onlookers will immediately protest. Satri or not, surely no DAC can run without a power supply? Affirmative. The DAC-21 doesn't, either. It runs off three Li-ion packs tucked beneath the purple motherboard. Here we recall that well before Vinnie Rossi's groundbreaking Lio, Bakoon already had a power-cycling aka indefinite battery supply which charged one bank while it drew from the other before rolling over. Not so this deck. After about 12 hours of use, the DAC-21 will run dry to then need 3 hours to recover 80% and 6 hours for a full charge. That's no different from their—or any other—portable headphone amp. For socketry, there's USB and coax in and 2.2V RCA and 2.2mA BNC out. Data acceptance goes up to PCM 32/384kHz and DSD256 for Windows, DSD128 for iOS.

Available skin colours are black, gun-metal grey or clear-anodized silver aluminium. Dimensions are 19.5 x 23.7 x 5.5cm WxHxD and weight is 3kg. Neither is the DAC-21 a big boy on functionality nor size. Anyone wanting Toslink, AES/EBU, balanced outputs, volume control or a full-width case leaving weight dents in the shelf looks elsewhere.

Like the now discontinued AMP-12R which put out only 15wpc but did so at 'Aha' quality, the DAC-21 goes after the less-is-more audience. To learn more about the less, I asked Soo In about the usual drill—passive or active I/V conversion, DAC and receiver chips, clocks, buffers, galvanic or opto isolation—then whether the DAC-21 can play and charge at the same time and how one knows how much play time remains.

ESS conversion chip with Crystek CCHD-950-50 'femto' clock oscillator, Crystek CCHD-575-26 clocks for 22.5792MHz and 24.576MHz, Atmel ATSAM3U1C 32-bit micro controller
Xilinx XC2C64A programmable logic chip, Microchip PIC16F-1937 controller and pulse transformer on S/PDIF input.

"The I/V conversion is very unique as it is actually the Satri circuit right after the ES9018S chip's current output. Satri is a current in/current out topology, thus its output current goes into the analogue filter stage whose resistor converts current to voltage. From there the signal hits our zero-feedback output buffer first introduced in the HPA-01M where it replaced our previous Jfet buffer. That's the whole signal path for the RCA outputs. The Satri links encounter another resistor to change voltage back to current. As for clocks, we use three separate ultra-low phase noise Crystek units which, I believe, some manufacturers refer to as 'femto' clocks.

"We tried optical isolators during R&D but concluded that they provided no meaningful benefits for either sound quality or measurements. So we don't use them. The ultra-low impedance battery supply with three separate Li-ion triple battery packs for a total capacity of ~100Wh(!) powers the digital and analogue circuits separately. The charger circuit inside the DAC-21 is quite sophisticated. Like the HPA-21, HPA-01M etc, it only charges when the power switch is off. This prevents any possible noise contamination during play. If the battery is low, the LED on the front panel starts to blink. The USB transceiver is based on Amanero but executed with our own hardware."

Tracking progress of Bakoon's FedEx parcel, it started in Korea's Suwon-Si, continued on to Incheon-Si Jung-Gi, then left for China's Shanghai and Guangzhou before turning resolutely west for Germany's Köln. From there Standstead/UK was the next hub, then Dublin to Shannon airport and back to Dublin. On that last leg, FedEx miscalculated though should have known better. Whilst Shannon is on Ireland's west coast like us, there's no delivery truck servicing our remote area. Back to Dublin it was to hop on the final van. It made the DAC-21 quite the traveler. An Irish gypsy perhaps; those are called travelers as well.