The interface DI-20 by  Audio-GD is based on a USB module Amanero Combo 384 coupled to a pair of Accusilicon 90 / 98M clocks. The circuit is designed to provide plethora of options regarding clocks use strategies: interfacing from the internal clocks, following an external clock (slave mode) or offset of the internal clock to another device (master mode). This type of circuit allows for integrations in highly advanced audio systems.

A logic circuit FPGA (Altera) is in charge of managing & generating the output signal. This high frequency chip is isolated from the USB interface to prevent noise and distorsion on both the digital signal conversion circuit and the clock signals.

Amanero interface 384

An Amanero 384 USB to I2S interface module provides a signal I2S / DSD from a USB digital source.

This circuit supports PCM signals ranging from 44.1Khz 48Khz 96Khz 88.2 176.4 192Khz 352.8Khz to 384kHz and provides an I2S 32bit output format as well as DSD64, DSD128 - and Windows Native DSD256, DSD512.

FPGA logic circuit & Accusilicon dual clock

The high-speed circuitry ALTERA FPGA has multiple purposes. This high-precision interface's primary function is to generate SPDIF  signals (on coax output & ACSS output). However it also provides control for clock signals and manages the options defined by the user on the front pannel.

This chip can output PCM signals up to 384kHz and DSD (DOP)

The algorithms used by the chip has been specially adapted by Audio-GD to meet audiophile requirements while taking account of the strengths and limitations of the actual device hardware.

This version of the DI-20 features a pair of clocks Accusilicon 90 / 98M. This extremely low phase noise crystal oscillator (less than 90dBc @ 10Hz) is intended for professional recording equipment as well as audiophile electronics precision devices. The AS318-B-100 provides a very low jitter - measured 0.2ps on the 10Hz-1MHz band and 0.071ps on the 12-80MHz band.

Optimized connectivity for digital

The DI-20 has the following inputs :  

• a USB-B connector (USB Amanero)
• a SPDIF input.
• a dedicated input for external clock signals (dedicated to uses in slave mode).

At the output, there is a rich set of connectors and different technologies:

• an AES-EBU output
• a S / PDIF coaxial,
• a ACSS output 
• an I2S output on a LVDS HDMI connector.

Control panel

On the front pannel, there is a very useful control screen which displays to view in real time all playback settings.

The display shows : 

•  the active input (USB / COAXIAL)
• the activity clock (internal clock / external clock)
• the sampling frequency.

The control panel provides access from the front to the clock options and the input selection.

Oversized power supply

Following Audio-GD tradition, particular attention was given to the design and integration of the supply circuit.

The DI-20 has its own regulated linear power supply built around a toroidal transformer Rcore and R-13 double separate power units. This allows for separate power supply on each signal circuit in order to avoid the propagation of noise from a circuit to the rest of the device with a significant impact on the accuracy of the clocks and logic chips.

The power supply circuitis separated from the signal components by a thick aluminum plate. This shield prevents the diffusion of noise and interference.