AA Music Server (AAMS) gives high-performance digital audio playback without the need to break the bank account. It uses the beautiful Streacom FC-10 fanless case available in silver and black colors, with or without optical drive slot.
Computer-based system
ASRock J5040-ITX motherboard based on Intel Pentium Silver SoC (Intel’s code name = Gemini Lake Refresh) gives the required performance in audio playback without compromise to dynamics, hence negates the need for expensive high-current linear power supply unit (LPSU) when more powerful CPU is used.
The use of standard motherboard allows future upgrade when better low-powered CPUs and motherboards are available in the future. Short-length SATA cables are used for better performance, and these can be upgraded/replaced with audio-grade SATA cables.
LPSU Details
Custom-made toroidal transformer by Toroidy based in Poland is used for stepping down AC line voltage. It is low-noise, audio-grade transformer with primary/secondary static screen, outside magnetic screen, and center potted with epoxy. AC power supply wires are double shielded.
Unlike DIY music server approach where power supplies (yes, plural) need to be purchased separately and housed in different cases with messy external wiring, AAMS has everything inside 1 beautiful chassis.
Neotech Hook-up Wires
Neotech SOCT high purity UP-OCC copper solid core wires in 18 and 16 AWG, sheathed in red, heat resistant Teflon, are used for internal DC wiring. They are the shiny Ferrari-red looking wires seen in the pictures and labeled with voltages or signals.
6-rail LPSU Main Board
The AC to DC rectification, smoothing, and first-stage voltage regulation for the 6 rails are done on the main PCB.
The motherboard is fed by the following independent 4 rails. These 4 rails have the second-stage voltage regulation on the main PCB as well.
- 5V Standby
- 5V ATX
- 12V ATX
- 3.3V ATX
Voltage regulators are from Texas Instruments used with ripple rejection enhancement circuit.
Good quality components are used in the LPSU board, including Nichicon UKG smoothing aluminum capacitors, Nichicon UFG “Fine Gold” MUSE capacitors for voltage regulator ripple rejection, the expensive KEMET 22uF tantalum voltage regulator output capacitors, and WIMA bypass capacitors.
Separate 5V voltage regulators’ board for storage and USB Audio
A dedicated dual-stage regulated 5V rail can support up to 4.5A total current, supporting up to 3 devices in total. For example, it can be 3 SSDs or 2 SSDs plus an optical slim drive for ripping audio CDs. Nichicon UFG “Fine Gold” MUSE capacitors are used as the output and ripple rejection capacitors alongside with WIMA bypass capacitors.
A dedicated triple-stage regulated 5V rail with floating ground is meant for AA USB2 isolator card. Vishay MKP bypass capacitors are used only for this rail, replacing the WIMA bypass capacitors used elsewhere. Please note that the third-stage voltage regulator for USB Audio use is Analog Device’s LT1963A which costs more than TI’s LM108x series.
USB2 Isolator
Even with a good LPSU, when the CPU is running, the CPU and supporting chips generate noise, which when bypassed, goes to the common DC ground. To ensure these noises do not get transmitted to USB DAC, we designed our own USB2 Isolator. The sound quality improvement is significant, even for DAC which already has USB ground galvanic isolation.
Operating System and Playback Software
We experimented with various playback software and O/S (Linux and Windows). Eventually we settled with Windows 10 IoT Enterprise LTSC custom-built with the unnecessary components removed or disabled (custom Windows installation ISO created). There is no need to use third-party software like AudiophileOptimizer or Fidelizer to optimize Windows further.
AAMS works as a headless PC. If any connection to AAMS is required, for example installing drivers or performing Windows Updates, it can be done remotely from a tablet (RD Client) or from another PC or laptop. Some Windows 10 literacy is required to operate AAMS. Online remote assist have been tested successfully as well.
We let customers choose Roon or JPLAY FEMTO or both to coexist. Roon has great user interface design and experience. JPLAY FEMTO is for critical listeners who want the best sound quality. By default, Roon Server is installed in AAMS but its license needs to be purchased by customers.
If Roon is used, TIDAL streaming is done using Roon. If JPLAY FEMTO is used instead, TIDAL Desktop on Win 10 gives the best TIDAL streaming experience and sound quality. User interface is through RD Client. For JPLAY FEMTO local music playback, mConnect (iOS, Android) and Hi-Fi Cast (Android) are recommended.
After the AAMS AC rocker switch is turned on, the front white LED turns on briefly and then turns off (POST – motherboard’s power on self test). Press the front left button once to start / boot AAMS – the white LED stays lit. If DAC is already connected, Windows startup sound can be heard form the hi-fi system. It takes about 30 seconds or more for Windows to stabilize and UPnP server visible within the home network. Depending on software used, launch the control app from tablet or phone. For JPLAY, select JPLAY FEMTOserver as Folder and JPLAY FEMTO as Renderer. Now ready for music playback control from tablet or phone.
To shutdown AAMS, stop music playback from tablet or phone. Press the front left power button twice. This initiates Windows 10 shutdown process. After about 20 seconds or less, the white LED turns off. The rear AC rocker switch can then be switched off.
Audition
If you would like to experience and listen to AAMS, please visit AFC Top Hi-Fi at Bandar Kinrara, Puchong. AAMS is connected directly to Denafrips Terminator Plus using AA Ref USB Cable. Please experience yourself the sound quality of streaming and local playback with AAMS using Roon or its alternatives.