Even though the ERCO merely offers one RCA input, almost the entire signal processing is carried out in balanced mode: On the one hand, the incoming analog signal is balanced directly after the input jacks, on the other hand, the proven ESS-Sabre ES9028PRO DAC chip provides a balanced signal itself. Since HEM has had the very best experience with the ES9028Pro, they saw no reason to switch to the current chip series from ESS-Sabre. The ES9028Pro processes PCM with up to 32 bit and 384 kilohertz as well as DSD256. A rotary switch on the back of the device allows to activate the bypass mode. This, however, is only possible by means of a screwdriver to avoid an unintentional activation, as in bypass mode the full output voltage is applied to the RCA and XLR outputs, bypassing therefore the blue ALPS four-channel potentiometer. The headphone outputs on the contrary are not affected by the bypass mode. Thus, even in an audio system with a preamplifier, both the converter and headphone amplifier can be used comfortably without switching or reconnecting cables.

Like the OOR, also the ERCO's internal power supply with its low-noise switching regulators, sophisticated filtering and linear low-drop voltage regulators (LDO) with fast transient response is the technological heritage of the HYPSOS. Actually the ERCO features two DC inputs as well: a classic 2.5/5.5-millimeter DC jack plug and a four-pin WEIPU plug, the same as on the HYPSOS. For the second option, the ERCO comes with a special power link cable with four-pin WEIPU connectors on both sides. In case a normal cable is used, the "4-Terminal Sensing Design" (4TSD) feature in the HYPSOS measures the voltage directly at the cable output, while when using the FPL cable it measures the voltage on the ERCO's motherboard instead. This allows the HYPSOS to regulate the voltage for the converter/headphone amplifier even more precisely.

But first, the ERCO has to get by without an additional power supply and accumulate a good number of operating hours. It turned out that even with a media converter like the ADOT, a few hours of break-in time improve the sonic performance, and this effect, as to my experience, is particularly pronounced with a digital-to-analog converter. In order to be able to run the ERCO continuously for a few days without blocking the systems in the study or living room as a result, the ERCO has to make do with a fairly simple environment to begin with, a set-up which should nevertheless represent a rather typical application for it: It fetches its data from a MacBook Pro via the supplied USB-A-to-C cable. The laptop sources the music files from an external USB hard drive - a rather questionable solution in terms of sound - and prepares them for the converter using Audirvana Studio, while the SendyAudio Peacock - my current favorite headphone right after the Stealth from Dan Clark Audio, which has long since returned to its distributor - is connected via the jack socket.