DACs — Kora DAC140

The DAC140 is the standalone converter of the Kora 140 series, built in Toulouse and priced at EUR 8,980 in France. It joins a streamer, transport, television or computer to a hi-fi system through nine digital inputs, and it takes its analogue output from the Square Tube circuit that the French maker also uses in its amplifiers. Inside it shares the digital architecture of the CD140 player, but here that circuitry is opened up to outside sources rather than a built-in transport.

Key specs that matter

Around the back sit four coaxial S/PDIF inputs, two AES/EBU inputs on XLR, two Toslink optical inputs and one USB-B port. USB accepts up to 384 kHz, while the eight other inputs take up to 24 bit and 192 kHz. Kora makes no mention of DSD playback. Output is available on both XLR and RCA, with a bandwidth of 20 Hz to 20 kHz and an internal impedance below 50 ohm. Internally the ROHM converter runs at 32 bit and 768 kHz. The case is 100 mm high, 420 mm wide and 340 mm deep without feet or connectors, and the unit weighs 6 kg. Power draw is below 40 W while playing and below half a watt in standby, on any mains voltage from 100 to 240 VAC.

Engineering and use context

An AKM receiver converts whichever input is active into I2S, and a second AKM part raises the resolution by a factor of over 64,000 before the ROHM chip, with a Kora clock circuit keeping all signals synchronised. The analogue side uses two ECC82 and two ECC83 double triodes. Kora builds the Square Tube as a complete operational amplifier - a differential input stage, symmetrical by nature, followed by an output stage close to an OTL push-pull. Because the circuit passes DC, it stabilises itself and holds the valve bias regardless of temperature or ageing. The input triodes receive a fixed 2 mA from a current source, and the stage runs from 480 V in total, of which only a small fraction is used. The home screen shows the selected input and the sample rate of the incoming stream, and inputs change with the single front knob or the DAC INPUT key on the remote. Like the other valve units of the range, a microcontroller supervises start-up and shutdown so that switching is silent.

Pairing

With balanced and single-ended outputs both fitted, the DAC140 connects equally to an XLR preamplifier or to a line input of a Kora TB140, TB200 or TB400 integrated amplifier. The PR140 preamplifier shares its case width, and the USB port lets a computer act as the source.

Alternatives

The nearest Kora alternative is the DAC module for the PR140, a slide-in drawer converter with two coaxial and two optical inputs that uses the same ROHM conversion resolution.