DACs — Aries Cerat Ithaka Minor

The Ithaka Minor is an Aries Cerat ladder DAC that places the TriodeFet output technology of the brand's larger Ithaka model in a smaller format. Where the Ithaka runs two converter banks per channel in a differential arrangement, the Minor uses a single bank of 12 parallel converters per channel operating in single-ended mode. The ladder architecture avoids both Delta-Sigma and multibit designs and switches a passive resistor network without manipulating the data stream or applying digital filtering.

Key specs that matter

Each channel carries 12 R2R converters with single-ended current output, all of them top-grade Analog Devices AD1865 chips. Inputs cover USB up to 24 bit and 384 kHz, AES/EBU and S/PDIF. The analogue signal leaves through RCA sockets, rated at 10 Vrms as standard and 30 Vpp at 0 dB, and through balanced XLR connections. The main unit measures 480 x 490 x 165 mm, and the complete system weighs 140 kg.

Engineering and use context

Op-amps and resistors play no part in the current-to-voltage step. Instead, custom wideband transformers take the converter output and turn it from balanced into single-ended form. The output stage is a first-generation TriodeFet design running in Class A with an idle current of 0.5 A, built as a single stage in single-ended configuration, and it is strong enough to drive a loudspeaker at up to 8 W. An external chassis houses the power supply, built with two low-noise 400 VA toroidal transformers. Its filtering is cascaded across four independent pseudo-battery systems, and the TriodeFet stage receives high-current rails filtered by three chokes, with about one farad of capacitance across the whole system. A Super Clock circuit re-clocks the refresh signals of the converters, while 70 LC filtering networks, each pairing an RF choke with a fast capacitor, decouple the digital circuits from the power rails.

Pairing

The output stage presents an impedance of just 1 ohm. The Ithaka Minor was first shown as an upcoming model in October 2024. The mix of USB, AES/EBU and S/PDIF inputs allows a computer and a disc transport to stay connected together, and both RCA and XLR cabling can run to the next component.

Alternatives

The Aries Cerat Helene is the smallest converter in the range, using eight AD1865NK R2R converters per channel with an E280F single-ended triode output stage, GZ34 valve rectifiers and a 10 V output level on RCA and XLR.