Fiio M3k

[Julian67]

I have flac files of 24 bit depth with sample rates of 48kHz, 88.2kHz, 96kHz, 192kHz.  All play fine on my Fiio M3k with Rockbox.  You might find that embedded cover art is causing a problem.  Sometimes an image file in the same folder as the audio file can prevent playback too.  Maybe check this by removing any images from file and folder and trying again.  If the file now plays then you can convert the image file to one that Rockbox can render, and restore it to metadata/folder/both.

[amachronic]

Is it expectable behavior do not play flac 9600Hz 24bit in native port? Original firmware does play that file.

It is supported but it won't play back at 24 bit depth (Rockbox will downsample it to 16 bit before playback). If cover art isn't the problem it could be a metadata parser or codec bug.

[vitt13]

Julian67, amachronic, thank you for your help. It was file's issue.
I removed cover art and metadata but it didn't help. Then I checked the file with 'FLAC Frontend' tool and it reported 'no errors found'. So, finally I re-encoded the file with that tool it has helped.

[benettonb1]

Awesome work! How does one go about installing this on the player?

Moderator Edit: Removed spam links.

[amachronic]

Instructions here. If you have any trouble just ask.

[aa666]

Hi!
isn't DAC power settings swapped?
second waveform corresponds to "Save battery" option, but it looks noticeably cleaner, then "high performance" one

//nevermind, looks like it's correct

[amachronic]

I double checked the DAC code and datasheet and the DAC should be configured correctly in Rockbox. Except it should be powering down the HP amp channels when changing the power mode setting, but isn't. I'll fix that, but I doubt it's the culprit since the DAC is powered up in high-performance mode by default.

If you're right the datasheet is screwed up -- the meaning of the LPMODE bit is reversed and should be 1 for high performance instead of 0. If this is true, the power consumption of the DAC should be higher in 'battery saver' mode - hopefully it's enough of a change to make a difference on a battery bench run, but it'll take me a while to test that.

Forgive me if this should be obvious, but why is the RMS voltage 1.16 V on your scope? it's roughly double the rated RMS of the DAC.

EDIT: if you made a mistake then no worries.

[aa666]

no mistakes
waveform looks cleaner in power save mode, and i have no idea why
but power consumption is less!
as for 1.16Vrms -
in datasheet: -1.5 dBFS, RL = 16Ω, HPG = +2 dB, THD+N < -20 dB | - 60 - mW
60mW at 16Ohm - that is 0.98Vrms, and i had no load
(those waveform were taken at volume level +2.5dB, at +3.0dB there are visible distortions already)

[amachronic]

no mistakes
waveform looks cleaner in power save mode, and i have no idea why
but power consumption is less!

It did occur to me that maybe 'high performance' just pumps more power through the amp and this ends up creating more noise. If you pay close attention to the SNRs on the datasheet for high power and low power mode, they seem to be trying to cheat by using the noise gate in some way - which detects all zero input to reduce noise when audio isn't being played. The SNR and output noise claimed is significantly worse when the noise gate is disabled. I can't see why it would have an effect like that on 'normal' audio; you need many milliseconds of zero samples to trigger it. Maybe the designers are just trying to artificially inflate the DAC's specs using unrealistic tests.

Do you get such bad noise in high performance mode if you reduce the amp gain? Also - you should use a volume in the range -20 to +6 dB which is a multiple of 2 dB to avoid using digital volume controls, since the amp gain goes in 2 dB steps. +2.5 dB volume translates to +4 dB on the amp with -1.5 dB digital gain.

as for 1.16Vrms -
in datasheet: -1.5 dBFS, RL = 16Ω, HPG = +2 dB, THD+N < -20 dB | - 60 - mW
60mW at 16Ohm - that is 0.98Vrms, and i had no load
(those waveform were taken at volume level +2.5dB, at +3.0dB there are visible distortions already)

Oh yeah, the datasheet is at 32 ohms so that makes sense.

[Julian67]

I think it's the case that in low power mode the DAC always operates at 44.1kHz and 16-bits but in high power mode it will not resample or truncate bits when dealing with "hi-res" audio.  But as Rockbox does everything in 16-bits it makes sense to only use low power mode.  The high power mode only seems to make sense for the original firmware.  I'd never thought about this before seeing the recent posts but after looking at the pdf for the AK4376 DAC it does seem to make sense to forget about the high power mode for Rockbox and go for the extra battery life instead.   I've been using my M3K in high power mode for months until today, and the battery life was already phenomenally good.  If it gets even better I won't complain.

[sourex]

Hey,
i need some help pls @vitt13

I played the m3k file from you on a fat32 formatted SD card and then flashed it.
When the player starts it says: Error loading Rockbox. File not found. I then end up in the recovery menu.

The following error messages appear in the recovery menu: Install Bootloader Error: -1102
 But the worst thing is that I can no longer get into the flash menu. Can you help me please ??

[vitt13]

When the player starts it says: Error loading Rockbox. File not found. I then end up in the recovery menu.

Do you have .rockbox folder with extracted content from daily build on your SD card?
Flashing modified M3K.fw is just bootloader replacement, you also have to do that step: "Simply unzip a Rockbox build https://download.rockbox.org/daily/fiiom3k/rockbox-fiiom3k.zip to your SD card".

[7o9]

Having to actually extract a copy of Rockbox seems almost like an afterthought in the installation instructions in the first post of the installation thread.

More emphasis on needing FAT32 (and how to achieve that) and having to extract a copy of a development build of Rockbox (and where to get that) besides installing the bootloader could help.

[amachronic]

Hey,
i need some help pls @vitt13

I played the m3k file from you on a fat32 formatted SD card and then flashed it.
When the player starts it says: Error loading Rockbox. File not found. I then end up in the recovery menu.

The following error messages appear in the recovery menu: Install Bootloader Error: -1102
 But the worst thing is that I can no longer get into the flash menu. Can you help me please ??

vitt13 is right. You need to extract the rockbox zip onto your SD card. The patched M3K.fw installs the bootloader, so there is no need to install it again from the recovery menu (although doing so doesn't hurt). Sorry for not explaining things more clearly.

The error message just means "bootloader.m3k" could not be found on the SD card so the installation did not continue. It's nothing to worry about.

You can get back into the recovery menu by holding Volume Up when booting.

[sourex]

sorry for the beginner's mistake, but I hadn't read that anywhere.
I thought so, but wanted to be sure.
@amachronic
Don't apologize because I missed something somewhere. Great job guys!

thx for help !