Audiobyte continues to raise the bar with it’s latest USB audio playback bridge.
Over it’s predecessor, the Hydra Z has a completely redesigned digital board that changes the way the it’s powered, a new output configuration, new chassis and many other refinements.
It can be powered directly from USB, from an external fixed 5volt power supply or from the dedicated Hydra ZPM power module.
The new Hydra has a full aluminium chassis, with a 10mm thick front panel. All connectors are conveniently placed on the back panel.
A 5Kv isolation barrier is used to prevent any leakage of the noise from PC to your sensitive audio system. USB isolation for audio devices is nothing but tricky. If you choose to use USB isolators, then the sample rate will become limited, which is not an option. If you choose to isolate the output, you are adding significant amounts of jitter to the signal. By using a clever circuit topology, the Hydra design avoids these two bottlenecks. The isolation is placed between the ARM processor and the FPGA audio core, therefore not limiting the bandwidth. Being before the clocks, its jitter contribution becomes irrelevant.
USB Arm Processing audio transactions are made through a powerful ARM3 processor. Therefore, the Hydra Z supports any sample rate available (384k PCM, DSD128) while being future-proof for any extension.
The Hydra Z uses cutting edge, custom digital processing developed into a Xilinx Spartan6 field-programmable gate array. The fpga is the “heart” of the Hydra. This advanced programmable circuit is offering a bit-transparent processing and signal conditioning to all outputs. It also gives the ability of the Hydra to output raw dsd audio streams.
Unlike other products which only specify "low jitter clocks", here is exactly what you will find inside : 2xCCHD-950/957 type from Crystek. These are real audio grade clocks. These clocks are system masters. In order to remove any jitter induced by the FPGA circuit itself, special retiming is applied just before the Hydra Z outputs.
Careful PCB layout is often neglected in the rush of getting a product quickly into the market. The Hydra Z design time took lots of work until everything came into the right place, until the shortest routing paths, the best decoupling places, the less interference and crosstalk placement for the components are found. Selected quality components (active and passive) are used for guaranteed long-time performance.