The streamer 2.16X can roughly be classified into three categories:
1) The linear PSU
2) The computer components
3) The software
1) The linear PSU is designed in-house and contains three transformers providing four main power rails from which all separate voltages for each part of the streamer are regulated. Every part of the streamer has its own dedicated regulation from the corresponding power rail. For example, the ATX to the motherboard contains 5 different voltage levels all having their own linear regulation.
Also, each SSD has its own linear regulation. There are two reasons to use three smaller transformers instead of one big transformer. First, Smaller transformers are more stable under high current swings and have less chance of humming during high current peaks. Second, yet most important, each transformer is used for its dedicated area of operation. One for the processor, one for the motherboard and one for the peripherals. A streamer supply has a highly peaking current load, and all currents add up in the transformer core and interact with each other. By separating the main areas of a streamer, in each transformer, the interaction is less which will improve the final sound quality.
Why do we use chokes in your power supplies?
Due to its intrinsic properties, a capacitor buffered power supply does not draw a continuous, but a highly peaked current. Each 100Hz capacitor is filled up for the full cycle in only microseconds, depending on the duty cycle of the power supply. The higher the capacitance and the lower the inductance (and Rdc) of the transformer, the lower the duty cycle and the higher these peaks are. These peaks introduce large Hf-noise in power supplies. In Pink Faun power supplies, we use high inductance power transformers (low field saturation in the core) and pi-filtering to keep the peaks at a minimum and thus Hf noise. The less rubbish in, the less we have to filter later.
Why do we use separated power rails and not one single mains supply?
All loads, in the end, come together in the source of power. In this source, they interact which results in harmonics and intermodulation noise. The earlier all separated loads are split in the device, the less they interact rendering the lowest initial noise in power supplies. Also, by using a lot of smaller separated and regulated supplies, we can keep current loops very minimal and local, which also will reduce the spread of EMC inside the device. This is why Pink Faun streamers use separated rails for dedicated areas and a separated regulator for each load. We take extreme care in adding these power supplies all together in one-star ground. In addition, we diligently source the ingoing voltage from star outputs in the power supply resulting in minimal interference and minimal Hf noise and harmonics.
What can we do to get the lowest noise possible in the streamer power supply?
Even the best regulators have very poor Hf-characteristics. Regulator noise itself is a factor in the final supply’s output noise, but even of more importance are the noises of the main power, EMC noise (from outside and the device itself) and noise generated by the rectifying and current peaks of the capacitors. All these noise sources have to be minimized to let the regulator perform optimally. Therefore, we focus on special low inductance transformers, Schottky diodes, low ESR-capacitors and plenty of common and differential mode Hf-filtering, separated rails, regulators with localized current loops, star sources and ground, shielded power planes on the PCBs, cable setup, etc. In the end, the final result is the addition of all efforts taken directly from the main input of the power supply to the connector of the motherboard.
2) The computer components are chosen for their stability and excellent performance. The streamer 2.16 can easily handle all PCM streams and DSD up to DSD512. Because of the stable and powerful processor, the streamer 2.16 can be configured with the minimum buffer-size in both ROON and HQPlayer. The processor is passively cooled with an 8-pipes cooling system and can handle the high DSD sampling easily. Playing normal Redbook audio, the load on the processor is between 0 and 1 %. Upsampling Redbook to DSD512x48 (HQPlayer / Poly-Sinc-XTR-2 filter) the load is between 12 and 16 %. The streamer standard has a Samsung Pro SSD for the Linux OS and there’s room for 2 more SSDs for music storage.
One of the main differences between the standard 2.16 and the 2.16X is the heavily modified motherboard.
For an even better performance, the motherboard of the streamer 2.16X is equipped with two OCXO clocks; the system clock and the BCK. The system clock is needed to synchronize all components/clocks on the motherboard. This clock also synchronizes the clock for the CPU, but the CPU clock is only used on the chip (PROCESSOR) itself. We only use motherboards with the an external CPU clock, not with an integrated CPU clock. Because the CPU needs to perform more operations each time than the motherboard, the clock frequency will be multiplied in the CPU. The advantage of using an OCXO clock on well-chosen key areas in the streamer 2.16X does not apply to the better stability but the low phase noise rendering low-jitter, which results in a more stable system making fewer faults in the process and lower latency. Both OCXO clocks on the streamers 2.16X motherboard have their own low-noise linear regulation, which results in a lower noise floor in the whole system increasing the listening experience dramatically.
3) The used OS on the streamer 2.16 is a heavily modified version of Arch Linux (Low Latency / Real-time kernel / Headless). The advantage of using Linux is that you start with nothing and only configure what you really need for audio playback. The Pink Faun streamer 2.16 can work standalone and is fully controllable from a tablet and/or smartphone. The streamer 2.16 runs in a headless mode which means there’s no video driver loaded which results in an even lower noise floor in whole the system.
The default playback software is Roonserver. For those who want to up-sample all music files to DSD (maximum DSD rate depends on the DAC), HQ-Player-embedded is installed as well and can be activated at all times. We have chosen for the Arch Linux OS for several reasons. One of the main reasons is HQPlayer-embedded is Linux only. Linux is a very stable and reliable OS which can be modified substantially.
Also, and most important, with Linux, we can reach an incredibly low latency (audio latency and processor latency). During the process of developing the streamer 2.16, we found out that latency is one of the key elements to achieve the really smooth and natural sound; the lower the latency, the better. That’s why buffer-size is always turned off, or chosen at the lowest option possible in the playback software. Because the latency is so low in the streamer 2.16 (Audio latency at 192 kHz < 2,67 ms on AMD Ryzen processor and high quality digital audio interface. Audio latency at 44.1 kHz < 1 ms depending on hardware configuration. Incredibly low processor latency average 4-6 microseconds on AMD Ryzen processor ) we need a solid stable processor and therefore we have chosen the AMD Ryzen 8-core processor.