Sorry for take a break from this thread in past two weeks, have been tied up with preparing the N5 launch and and tour arrangement.
There are several issues related to power reset and /or shut down reported recently, there are some “general” information that I want to share with you before I check out the detail of individual cases.
1. Reset when plug in/out headpone
The headphone output of N6 will detect whether you have inserted a headphone into the player. If you unplug your headphone during playback, the player will pause immediately. In case you have enabled “Idle Shutdown”, N6 will turn off itself at the end of predefined idle time out period, this is a very handy power saving feature and the headphone detection function played an important part.
On the other hand, if you has enabled “breakpoint resume”, when you turn on the player without plug in your headphone, the player will boot up as normal, but as soon as you plug in your headphone, N6 will resume playback at where you left previously. I find this very handy as well, and almost cannot turn back to DAP without headphone detection.
Unfortunately, headphone detection does come with a small prize. The way to detect whether a headphone is inserted is by applying a small current to one of the pin at the headphone, so when you unplug the headphone, the current will break off, and when you plug in, the current will resumed. The problem is, if the headphone connector is not too tight and shake slightly after plugged in, or if you plug and unplug your headphone quickly (or the other way round), the action will cause a current shock at the headphone detection system, and this will trigger the N6 to go into protection mode. The common consequence will be auto shut down, and occasion the player will freezed at the protection mode and cannot shut down itself, this is in fact a software glitch and you can get out of the problem by a hard reset.
(2) Reset option
There are two different ways to reset the N6. Insert a pointed object into the reset hole next to the USB charging connector will reset the SoC (System on Chip), this is sufficient in most situation. If the problem remain un-rectified after a SoC reset, clicking the reset button repeatedly doesn’t solve the problem, you need a compare system reset. Remove all the TF card and output connections, press the power key continuously for 10 seconds (or 12 seconds, I don’t remember the exact figure), and the player will hard reset, and you can insert TF card and connect to headphone again to check if everything is alright after the reset.
(3) Batter Capacity Detection
The N6 firmware has displayed the batter capacity in a percentage reading, this is a linear representation of the battery capacity. However in real life, battery capacity is NOT a linear function against common measurable such as current or impedance. The current capacity will drain at a non-linear rate and N6 simply “predict” the current capacity base on a number of historical and system internal measurement, it is a lot more complicated that checking a parameter and lookup a % value from a reference table etc.
As of today, the batter capacity deduction feature is still far from perfect. Once the battery capacity reading drop below 20%, the deducted value will become not-so-accurate and we suggest you arrange a charge up ASAP, because of long-term (lithium) battery health and the potential inaccuracy of the deducted battery capacity problems. Occasionally, the battery calculation function will run into an error which will lead to a randomised freeze up of the feature, the battery will continue to drain but the batter reading will not updated as it should be. In other words, users were misled by the reading and assume the there are still lots of battery power in the player, and then the player shut down suddenly because battery has run out already. When you run into this situation, the player will resume after you charge up the battery. Cayin will look into this problem and try to rectify in subsequent firmware, but right now the problem seems to be fairly randomised, so finding a cure will take more time than we can anticipated.
We are not saying all the auto-power-down or reset issues are because of these three problems, We shall look into individual cases later on and find out what exactly are causing problem to our users and try to improve our N6 to a more stable and efficient stage. For the meanwhile, if you run into any of the three problem listed above, please take associated procedure as advice without confusing as some major/critical hardware problem in your player. Feel free to contact me if you run into such situation which you believed is different from the three problems listed above, will keep trace of them and channel to Engineering team ASAP.