Zesto Audio Athena DAC

A tube output DAC with ROHM conversion, native PCM up to 32-bit/384 kHz, DSD512, seven digital inputs, and balanced transformer outputs

The Zesto Audio Athena DAC combines modern digital conversion with Zesto’s tube analog output circuitry. Built around a ROHM DAC chip, Athena is designed to preserve the integrity of the digital signal while adding the dimensionality, texture, and ease that Zesto is known for in its analog components.

Native Conversion With No Upsampling

Athena operates bit perfect, with native playback and no upsampling. It supports PCM files up to 32-bit/384 kHz and DSD up to DSD512, with inputs for USB, optical, coaxial, AES/EBU, and I2S. The goal is simple: accept the source format as delivered and convert it cleanly, without imposing extra digital processing.

Tube Output Stage

The analog stage is a Class A, dual-mono vacuum tube design using two ECC82/12AU7 tubes and two ECC832/12DW7 tubes. The 12DW7 tubes handle input duties and drive the output tubes, while the 12AU7 tubes drive true differential balanced output transformers. The circuit uses no negative feedback, and Zesto performs output filtering through the tube output stage rather than adding filters after it.

Noise Control and Grounding

Athena uses a proprietary grounding scheme, a 4-layer copper printed circuit board, 12 internal DAC power supply/regulators, and Zesto’s ESP power supply architecture to reduce digital noise and support the tube output circuits. Independent left and right ground lift switches are provided to help eliminate ground loop hum in real-world systems.

Handmade in the USA

Each Athena DAC is handmade in the USA and receives a 50-hour factory burn-in on all circuits and vacuum tubes. The chassis uses a 16-gauge zinc-plated steel enclosure, with gold-plated RCA and XLR output connectors using isolated grounds.

Features

• ROHM DAC chip
• Native bit-perfect conversion with no upsampling
• PCM support up to 32-bit/384 kHz
• DSD support up to DSD512
• Seven digital inputs: USB, 2 optical, 2 coaxial, AES/EBU, and I2S
• Class A, dual-mono vacuum tube output stage
• Balanced transformer XLR outputs and single-ended RCA outputs
• No negative feedback
• Independent left and right ground lift switches
• Handmade in the USA with 50-hour factory burn-in
• Two-year limited warranty, six months on tubes

Specifications

Inputs: USB, 2 x optical (S/PDIF), 2 x coaxial RCA (S/PDIF), AES/EBU, I2S

Outputs

Output Stage: Class A, dual-mono vacuum tube output stage

Balanced Outputs: 1 pair true XLR transformer balanced outputs, pin 2 hot

Single-Ended Outputs: 1 pair RCA outputs

Output Impedance: 300 Ω

Maximum Output Level: 3 V RMS

Ground Lift: 2 independent ground lift switches for left and right outputs

Output Connectors: Gold-plated RCA and XLR, recessed with isolated ground

Negative Feedback: None

Digital Performance

DAC Chip: ROHM DAC chip

PCB: 4-layer copper printed circuit board

PCM: Up to 32-bit/384 kHz

DSD: DSD64, DSD128, DSD256, DSD512

Upsampling: None

Output Polarity: Non-inverting

Vacuum Tubes

Output Tubes: 2 gold-pin JJ ECC82/12AU7

Input/Driver Tubes: 2 gold-pin JJ ECC832/12DW7

Tube Sockets: Gold-pin ceramic sockets

Power

Power Consumption: 30 W, 0 drain when off

Voltage: 100 V–120 V AC, 60 Hz

Optional Voltage: Factory-installed 220 V–240 V AC, 50 Hz/60 Hz

Power Connector: Standard 3-pin 15 A IEC

Power Switch: Side-panel on/off switch

Power Supply: Internal ESP Supply toroidal transformers, 1 300 V and 1 12 V

Additional Power Supply: ±15 V switching power supply

DAC Power Regulation: 12 internal DAC power supply/regulators

General

Construction: 16-gauge zinc-plated steel enclosure

Dimensions (WHD): 17" x 5" x 12" (431.8 x 127 x 304.8 mm)

Weight: 25 lb. (9.3 kg)