[looki look]

If the LDAC color display is normal, the settings should be normal, you can enter the FiiO Control APP to see if the settings are correct?

yes fiio control app looks everything fine. It also looks fine in music app under bluetooth connections or so. everything looks fine except that the k9pro
has no output on headphone when I play music.

 

[looki look]

Connect something on line out some speaker or aux speaker or something, Fiio K9 Pro uses a digital switch which switches when the front switch change/slide with a click sound, so some they they act up and send the signal to dac mode even the switch is on HP mode.
Its happening for me on high gain only, so you can also test if that's the case.

yes thats the case. I connected pc speaker. I now switched to dac and back to HP. Now I have output to HP, but its not usable ... i'm now on high gain and 100% (max) volume knob and I just hear it. The volume at 100% with bt in is only as loud as on coax input and volume at around 10 oclock or even less.
also the line out is not loud (neither dac nor pre mode on max volume). my sonos is much louder on line out. I also have to go to max volume on speaker to hear low volume. Loud is not possible neither on HP (when it makes output) nor line out pc speakers.

 

[ATimoff]

@Davywhizz Digital PCM filters have a particularly noticeable effect on sound in digital streams of higher quality: coaxial/optical/USB. Don't test it on BT. The BT channel works with losses. In good DACs, the BT module is equipped with a relay for physical disconnection from the power supply circuit. The noise from BT module radiation is noticeable throughout the sound path. Which reduces the overall dynamic range of the DAC! Here BT is rather necessary for the control program... For audiophile sound, this is evil.... By the way, about filters. They show the sound nature of the DAC well. On a detailed and neutral-soft AK4499 chip, I also like 3) or close. And on a chip with maximum detail and neutral-brightness, I prefer the classic "slow roll-off". But this is the subject of discussion. By the way, the ES9038Pro should have 7 filters, not 6.

​

 

[looki look]

can you try turning up the volume of your phone?

sorry for several posts in a row ... i go through the posts... I have now the volume of phone increased to max (even higher than recommended .. the phone asked me if I want to go higher than that) now the volume output of k9pro is normal (listening at 1 oclock as with coaxial input). And I switched k9pro off and on with back power switch and reconnected the phone via BT and now it works directly without that I have to switch to pre/DAC and back to HP. I wonder if it will happen again when I use coax input inbetween, but for now I have at least a workaround. The solution was Moons Tip in Post #987 (switched to DAC and back to HP) and FiiO Willsons Tip to increase the volume on the phone.

 

[looki look]

@ATimoff: I also just wondered what happens with my CD quality files (44,1khz) when bt mode is like now aptx adaptive 48khz then the phone does a upscaling to 48khz ? Is there a bt mode "passthrough" or a player app that can transfer the original file directly to k9pro, so that k9pro plays my 44.1khz unmodified in 44.1 khz. I saw I could change to a 44.1 bt mode, but I would like to have it done automatically depending on the music file I play.

 

[ATimoff]

@looki look Oh... that awful BT ... his problems ... Of course, there is a problem of unwanted oversampling everywhere. In Linux, this is solved by setting 2 frequencies for all applications by manually editing the PulseAudio configuration. In Windows, playback via "JRiver" or "foobar2000" directly bypasses the system using the ASIO/wasapi driver, or you can go by manually configuring the general OS sound mode. In iOS, I did not observe unwanted oversampling. Using the player "Fiio Music" or "foobar2000" on your phone will not solve your problem?

 

[ATimoff]

I found more ... here is an approximate translation from one Russian-language forum about the f2k player, I quote: ".... wow! I've never seen a player on Android where you could change the sampling rate yourself! If I'm not mistaken, correct me. Sounds better..."

 

[ATimoff]

@looki look I'm sorry. It looks like translation difficulties. It is clear from your previous post that you have already tried "f2k" and "Fiio music", but they do not work with BT or do not help to transfer 44.1kHz? That's what I didn't understand. Can you also try "jRriver" for "Android"? For me, "Fiio Music" for iOS is enough for all occasions. The exact flow is preserved. Tested the checksum.

 

[Vitaliy Belz]

Will this plastic shield lead to rapid degradation of electronic components?

 

[ATimoff]

The picture is impressive! They will not degrade if there is no strong heating of the components. I recently watched a movie about the vintage assembly of a top-end DAC on this AK chip. There, almost all operational amplifiers, power modules and the chip itself were covered with cooling radiators... Everything is arranged differently here. Are they really not heating up?

 

[Vitaliy Belz]

The picture is impressive! They will not degrade if there is no strong heating of the components. I recently watched a movie about the vintage assembly of a top-end DAC on this AK chip. There, almost all operational amplifiers, power modules and the chip itself were covered with cooling radiators... Everything is arranged differently here. Are they really not heating up?

Of course it's warming up! I'm not even confused by the lack of radiators, but by the fact that they are all covered with this plastic. This definitely does not contribute, coupled with the almost sealed case, sufficient cooling.
I would like to receive comments from Fiio.

 

[looki look]

@looki look I'm sorry. It looks like translation difficulties. It is clear from your previous post that you have already tried "f2k" and "Fiio music", but they do not work with BT or do not help to transfer 44.1kHz? That's what I didn't understand. Can you also try "jRriver" for "Android"? For me, "Fiio Music" for iOS is enough for all occasions. The exact flow is preserved. Tested the checksum.

All BT Modes are activated (or better none deactivated) and when I check the bt mode of k9 with fiio music or with fiio control the k9 is in the mode "aptx adaptive 48khz" (also the BT setup of the phone says it is aptx adaptive 48khz connected). The music file that I play is normal wave 44.1 khz. fiio music also says that the file is 44.1khz. I wondered: when the BT mode is 48 khz somewhere must happen an upsampling from 44.1 to 48khz either the music app or android/bluetooth driver does it. I'll do tests with 88.2khz files and see if the bt mode then changes, but then it also should change from 48khz to 44.1 (i dont like upsampling because it changes the data and it costs cpu).
Because all my music is 44.1 in the moment (except some 48 mp3) I could set the bt mode with fiio control to aptx 44.1khz.

 

[Ab10]

I like to know,

(1) All the EQ and Filter settings which can be accessed via Fiio control app applied for all mode i,e USB/OPT/COAX and BT or Just for BT mode?
(2) Applied for Amp only section too i,e Line IN mode?
(3) Is there any switch combination or pin whole to rest the whole K9 Pro to reset to factory settings?

 

[ATimoff]

@Ab10 Good question. Digital filters (6) are built into the DAC chip! Applies to any signal passing through the DAC! I don't know about the equalizer. I turn it off immediately. The equalizer is not Hi-End! He introduces distortions. I am a sound analyst. Look at the classic "response" graphs for short impulses. Real sound, in real life, is predominantly pulsed. This will help you better understand how the digital filter "finishes" the sound. Original source: https://velvetsound.akm.com/us/en/technology/

 

[llysender]

I like to know,

(1) All the EQ and Filter settings which can be accessed via Fiio control app applied for all mode i,e USB/OPT/COAX and BT or Just for BT mode?
(2) Applied for Amp only section too i,e Line IN mode?
(3) Is there any switch combination or pin whole to rest the whole K9 Pro to reset to factory settings?

1) Applied for all modes. The eq isnt very good as it causes bluring though, i found eqing via my software player much more effective.
2) RCA and 4.4 pentacon, no 2 3pin xlr is annoying but I dont have a need to line in yet so its fine for me I guess, although if I ever upgrade to a better dac needing a custom 4.4 to 2 3pin xlr female adaptor is going to be annoying.
3) no idea