Absolutely! If you use the USB input of the D2 Sender, then connect the D2 Receiver optical output to your DAC and the D2 will act as a wireless 24-bit USB-to-SPDIF converter and stream high-resolution digital audio to your favorite DAC. You can also use the optical input on the D2, in which case the D2 will act as a wireless optical link to your DAC. Can I use a third-party (non-Audioengine) AC power adapter to power my D2 Sender and/or Receiver? The D2 AC power adapters have been specifically designed to provide stable low-noise power to the D2 so only use the included Audioengine power adapters. Using any other power adapter will compromise the audio quality and may damage your D2.
We chose optical over coax inputs and outputs for D2 (and D1) primarily because TVs, Apple TV, and computers all have optical outputs. Regarding optical vs. coax quality, there are various thoughts and theories on which is better but our experience is that as long as optical is implemented correctly and the connectors are high-quality, it is essentially the same digital SPDIF signal.
The D2 Sender can simultaneously broadcast to (3) D2 Receiver units. See the Pairing section in the D2 Setup Guide for pairing additional receivers.
No. The volume information is transmitted via a completely separate I2C channel over the air and is used at the output of the internal DAC of the D2 Receiver to attenuate an analog output.
The D2 uses "adaptive mode" in it's USB receiver. This means that the USB receiver (Texas Instruments 1020B) will keep track of the data coming in from the computer and adjust so as not to miss any incoming data. Due to the nature of the wireless link, the data then becomes asynchronous before arriving at the Receiver. Thus the D2 acts as an asynchronous USB DAC with the added benefit of being 24/96 bit-perfect wireless.
If using a Mac, open the Audio MIDI Setup utility in Applications->Utilities, choose "Audioengine D2" under audio devices and check that the format is set to 96 and the bit depth is set to 24bit.
USB cable performance will vary with construction and length, however, for the best results we recommend using the shortest cable possible (2' or less).
The free Remote app for iTunes works nicely on an iPhone/iPad and there are plenty of free apps for non-iTunes based systems as well as Android-based apps.
Yes! You will need an Apple USB camera adapter, and a self powered USB hub. We've tested this with the D-link DUB-H4 and DUB-H7, and it works well. Here's an example of how this would be connected:
iDevice w/ USB Camera Adapter --USB-> Powered hub --USB-> D2 Sender --wireless-> D2 Receiver --RCA-> Speakers
You can use Audioengine DACs with your original A5s, no problem. You would simply use a standard RCA cable and the RCA to mini-jack adapter that came with the A5 to connect the RCA output from the DAC in to one of the mini-jack inputs.