Allo USBridge - USB Audio Output Kit (Volumio) Aluminium
Every DAC needs a source. For USB input, Allo created the USBridge. (DigiOne is for S/PDIF). This version comes with an Aluminium Case!
Basically, you have your music on the cloud or on your PC/NAS. If it’s on the cloud , you will use your smartphone to access your account and play. From your smartphone, in order to send the music to your DAC (DACs have USB and/or S/PDIF inputs) you need a transport that will be visible (to your smartphone / tablet /PC) as an Airplay device (iOS ) or UPNP/DLNA (Android/PC). Our transports have different outputs. USBridge feeds your DAC through USB, and DigiOne uses coaxial/bnc. Depending on your DAC inputs you need to make a choice.
This is a full USB Audio Output Kit, and includes:
- 1 x Sparky SBC
- 1 x USBridge
- 1 x 16GB EMMC (Embedded Multi Media Card) Loaded with Volumio
- 1 x Acrylic Case
- 1 x 5V 3A Power Supply (UK/US/EU)
So why not use a cheap laptop, Raspberry Pi, or even Sparky as a USB transport? Well you can, but they all have some limitations.
- First, laptops are noisy... very noisy. On USB we usually see spikes at 100mV of noise. That will have an impact on sound system.
- How about RPI? RPIs are great and very energy efficient, but on USB they have 2 major flaws. First is that bandwidth is shared between the 2 USB ports (so in fact there is only one USB), and second is that ethernet is also shared on same bus! Of course, you also have the noise on USB at about 60mV.
- Maybe Sparky? The 2 USB ports (next to the ethernet port) share one input to the CPU (split by a hub). Noise on USB bus is about 27mV (pretty good) and ethernet is completely apart (bus is not shared). So it's ok, but not great.
So we developed a new board that is connected to the bottom of Sparky. Sparky has 2 independent USB controllers (2 highways), and we connect to the second one. Then we use a new USB IC that recloaks the stream using hi quality NDK Oscillators, and everything is powered by independent LDOs and hi frequency filters. The final noise of the USBridge is lower than the noise of a battery.
What we have designed and achieved is a true USB output for audio.
Compatibility: OS Volumio and DietPi
Please note that you can feed the Sparky SBC separately with one PSU (5V / 2.0A) and USbridge HAT (5V / 100ma + whatever your DAC needs). Please check your manual before to open J28.