You need earphones/headphones with impedance higher than 20 ohms.

The amplifier is kept off if your headphones have impedance less than 20 Ohms for obvious reasons. Don't worry, if it is off it means you don't need it.

Thank you! but it is started work with same earphones and headphones wich impedance 20 or more. wtf?

What do you mean? I don't really get what you say. You mean now it is activated with the same earphones?
You should also know that not all the players are allowed to work with the DAC/amp. There is a list of apps allowed toe work with it and those apps that aren't in the list can't have access to DAC/amp therefore they can only work thorough embedded codec. While working through the codec, switching between amp modes has no effect. Is that what you are trying to say? Also, what player are you using?

Edited by Luqas84th at 2018-05-31 05:18

If You want activate "Hifi" for any earphone use "jack-jack angle adaper". First connect adapter, wait few seconds for headset icon on screen and than plug earphone. (Carefully, don`t listen do loud, You can destroy your earphones).

Try to use earphone with 21 Ohm or more. For example, "high gain" and "line out" doesnt work with my 20 Ohm Shure SE215.


For me HIFI is still don't work properly, "bug".
Source: http://forum.flymeos.com/thread-27116-1-1.html
In my opinion work only AMP without external DAC. Sound is similar like in my iPod Touch 4G. If You listen music in the background (I use PlayerPro) try to turn on "Shazam". You will see how change the sound (quality and volume). I did a lot of tests with different jack adapters, and earphones/headphones. This is weird, but now my Pro6Plus sounds much better. I think AMP + DAC is working right now properly. I don`t know what is causing (In the meantime I`m copied audio_hifi.conf  and overwritten it). But still i dont know where is the bug.
I "love" flymeos :/


(Pro6Plus, 6.3.0.0G, KZ ZSR 22Ohm, Sony MDR-1A 48Ohm)
I hope my English is understandable.

Edited by Oberonmeister at 2018-05-31 14:24

Okay, let me try to explain you the logic of the DAC/amp switching on and off.
First, DAC is supposed to work every time you connect your headphones and the app you are using for playback is in the audio_hifi.conf . If it is not in the list, the playback is performed through the codec embedded into the SoC.
Second, the amp is only working if the playback is performed through DAC and the device you connected to the 3,5 mm jack has impedance higher than 20 Ohms.
But there are many hidden triggers that can entirely ruin this logic. For instance, if you try to start some app that is not in the audio_hifi.conf and it will attempt to get the access to audio hardware while the other app that is in the list is performing music playback, the phone will automatically switch to the embedded codec. Yes, the app that is supposed to work thorough the DAC will be forced to codec too. This is what happening to your phone when you are launching Shazam while playing music in some other app. You will hear a noticeable bump in volume but the quality is obviously lower than that you can get from DAC.
There is a very easy way to check if your music is played through DAC/amp or the embedded codec. Try to switch amp presets in HI-FI section of audio settings. If it changes the volume level, your DAC/amp is working. If these settings are unavailable, it means that DAC is working but the device connected to audio jack has impendance less than 20 Ohms.
If you can switch modes with your low-impedance device and the volume level is not affected by it, it means the playback is performed through the codec.
I tried to edit audio_hifi.conf myself to add some players that are not there, but immediately found that any attempt to mess with any files makes the DAC/amp to just switch off completely. I mean, even those apps that were working through the DAC before now only play via embedded codec, which sucks major balls.
I "love" flameos for this just as much as you do. I can't help but feel like everything that has something to do with audio in flameos is done through the ass, just as many other things...

Yes. It is did not work with my headphones - bluedio UFO and earphones like sure 215 (Detachable earphone)  first. Then I removed earphones from cable and then connect cable (without earphones) to phone and amplifier Activate.

Edited by Luqas84th at 2018-06-01 01:07

Oberonmeister, all You write is logical. I know how this should working.
Maybe I expect too much for "hifi smartphone", but earlier my Pro 6 Plus and Pro 5 sounded "average" (for me).
Like i said, for a few days my phone sounds much better (I still use the same headphones KZ ZSR 22Ohm, Sony MDR-1A 48Ohm and Shure SE215 20Ohm). For me, somewhere is a bug that causes ESS ES9018K2M not always work (despite using the right headphones) - Low Gain, High Gain ale Line Out is available but (for me) sounded still like Wolfson WM8998.
I don`t have time to reinstall the 6.3.0.0G again for testing. Now I just waiting for officially Flyme 7. My phone seems to play correct (but i do not know why). Eh.

As I said before, if switching modes is available but makes no effect on sound level, it means the device outputs the sound signal through the codec instead of DAC. It happens when you are using a player that is not in the audio_hifi.conf, or it can be the result of some actions like launching the app that is not in the list while other app that is in the list playing in the background.
I also experienced a bug when while listening to google play music (which is in the list of apps allowed to work with DAC/amp) any notification or any other system sound forced the phone to switch to the codec and after playing the system sound it didn't switch back until I reconnect the headphones. However, this bug was only present on early dailies and is currently fixed.
A bit offtopic, but... Player pro is just bad sounding app by itself. I don't remember if it is in the list, but I remember it was sounding pretty mediocre. Among other players on the play store I like Poweramp the most. USB Player Pro is even better sounding and has more tech to it but unfortunately it is not allowed to work with DAC, so Poweramp is the only real choice for me. It sounds really good, supports bit perfect and direct volume control which even allows you to change volume in line out mode should you need to, and it has sox resampler which is unanimously considered the best in industry. If you ever decide to give it a try, make sure to activate a beta-testing mode in play store to unlock the direct output mode to be able to use DAC.
I have very little hope about possibility of global Flyme 7 ever being released, so I basically gave up on it and using Chinese firmware now.
P. S. Oh, I'm using Fiio F9 and Beyerdynamic DT770PRO if you are interested.