Description
QAP is the latest version of the popular RPI streamer build by QA. Omitting the DAC hat this time round resulted in a smaller chassis without the various output connectors. Essentially this does not scale back on the quality of the streamer, because the recent addition of the QLS Quloos USB DDC in our inventory has optimised very well as a pairing with the QAP. There is no longer any limitation placed on the RPI output with regards to the DSD and PCM output. As explained in QLS QU02 product page, the isolation of the USB in the DDC has minimised the effect of jitters one associated with USB audio, leaving this method of pairing and connection being probably the best in getting the highest quality out of all possible supported bitrates.
Retaining the screen and LPS circuits inside, the QAP inherited the best traits from the predecessor QAV. It is in fact more efficient in power handling now, with the heat generated being much more reduced without sacrificing on the current requirement. 3 stages of power filtering remain within the build to really give the RPI the best possible source of clean power, which is of utmost essence for RPI to stream in the highest quality output.
The first stage starts at the IEC input with a soldered EMI filter onto the rear IEC inlet. It will go to the R-core transformer for the stepping down of voltages before going through the second linear filtering stage and further regulated to a stable 5V voltage required. Then there is the final stage through the power filter hat which has a higher capacitance value than the standalone one in total to give the best possible power source to the RPI below. Having these excellent components of power source built inside QAP ensures the RPI is performing optimally without leaving much to be desired – because past experience tells us that if they are simply used as smaller stacks, they are seldom powered adequately, or worse, powered by noisy switch mode power supply, thereby not fulfilling the potential at all. Better fuse made for hifi from Rod Rain Audio is even used at the power IEC inlet, so the only thing that is having any influence to the quality of the power source now is simply the power cable. And for that, we highly recommend the Gotham 85025 Power Cable which is fantastic for use on source and DACs.
Secondary output of the R-core transformer goes to another regulator for the power of the external 3.5 inch screen mounted beautifully in front of QAP. The screen provides useful information like the date, time, and most importantly the details of the music being played and any album art accompanied. Clean, crisp and sharp, the screen panel is a delight to look at, displaying accurate colours. When music stops playing, it will automatically switch into screensaver mode, showing various beautiful imageries grabbed from the web server during this period. Many of the settings of the screen can be set under a plugin from Volumio, but the default appearance from QA will have been set to most users’ satisfaction.
Hook up wires from Gotham stayed in place to power the RPI filter hat from the LPS board.
R-core transformer is retained in the QAP for the excellence in keeping noise level low, resulting in a very clean and transparent background of the streamer. It also allows creative mounting within the chassis to keep the entire footprint manageable without getting big like what a toroidal transformer would.
The sleeker chassis design means the front of the unit is just a clean panel of LCD window. What was used to have a power button has not been integrated into the IEC inlet at the back. The rest of the usual RPI 4B connections sit beautifully and precise within the CNCed openings.
Screen is connected to RPI with an internal HDMI cable and only works with Volumio (tested). Using QAP as a Roon Bridge with Ropieee does not use the screen. The screen will show up the booting sequence of Ropieee, but they will be too tiny to be read, before shutting off when Ropieee is loaded. That is perfectly normal. Using Volumio as Roon Bridge will not show the current playing list unlike what it is when playing directly from Volumio, it will just show the sccreensaver images as though nothing is playing.
In conclusion, one could have powered a DIY stack with separate LPS and screen, but that will still remain as separates nonetheless – messiness and complication will arise, not to mention that will require 2-3 power plugs. The QAP is a self-contained unit to achieve everything with just a single power cable.
FREE shipping in Singapore. 2 years warranty from QA. Comes with 16GB microSD card with either Volumio or Ropieee OS installed. Setup guide included with purchase. Build and assembled on order up to 3-4 weeks lead time.
SPECIFICATIONS
- Dimension: 210*137*90mm (L*W*H)
- Weight: approx 2.1kg
- Power input: 220-240V (110-120V can be requested)
- Power rating: 20W
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