Headphones amplifiers — Erzetich Audio Scylla

The Scylla is the highest-priced headphone amplifier in the current Erzetich Audio price list, the Slovenian maker of headphones and headphone electronics, with a list price of 6000 EUR. Erzetich describes it as a fully balanced dual-mono class A design with relay-based volume control, and it was introduced alongside the company's planar magnetic Charybdis headphone, which the maker says was designed with this amplifier in mind. Below it in the catalogue sit the Deimos at 4000 EUR, the class A Perfidus at 999 EUR and the class AB Bacillus II + and Bacillus II at 1999 and 799 EUR, while the Medousa hybrid has left production. The Scylla is the only model in that list to combine class A operation with a fully balanced signal path.

Key specs that matter

The published frequency response runs from 4 Hz to 40 kHz within 1 dB. Erzetich states that the output adapts to headphone loads between 8 and 600 ohm. Connections are balanced only - a pair of XLR inputs for left and right at the back and one 4-pin XLR headphone socket at the front, with no RCA input or 6.35 mm jack fitted. The amplifier draws 25 W from a 230 V 50 Hz or 115 V 60 Hz supply. The chassis measures 510 mm wide, 140 mm high and 330 mm deep and weighs 9300 g. The maker does not publish an output power figure for this model.

Engineering and use context

Left and right are separate balanced class A amplifiers whose output stages stay switched on through the whole waveform, which accounts for the higher idle consumption compared with the class AB Bacillus models. Power supply smoothing uses 94,000 uF of capacitance per channel. Instead of a conventional potentiometer, volume comes from a digitally controlled attenuator that switches resistors through relays in 80 steps, avoiding the track wear and channel imbalance a carbon or plastic track can show at low settings. The enclosure combines steel and aluminium. Every Scylla receives a 12-hour burn-in before delivery, it is made in the EU, and Erzetich covers it with a 5-year limited warranty and describes it as completely serviceable. The wide cabinet needs a full-width rack shelf rather than a desk corner.

Pairing

Because there is no unbalanced input, the source must offer XLR outputs, which rules out many compact DACs with RCA only unless an adapter cable is used. Headphones need a cable terminated in a 4-pin XLR plug. The Charybdis, a 43 ohm open planar headphone, is the pairing Erzetich suggests.

Alternatives

The Erzetich Deimos is a smaller dual-mono class A headphone amplifier that also uses relay volume control.