[Clip+, Clip Zip, ClipV2, FuzeV2] Improve battery life, part 2

[asymsucon]

When decreasing from +6dB (i.e. in the + range) I hear sometimes a click (similar to transitioning the -40dB threshold).

I hear a pop too - sometimes on a +3dB mark going downwards, but it's very faint and almost unnoticeable.

[johnb]

the latest build does not improve the SDcard behaviour!

"
the variant 0 gets a little further on the Samsung card: I can browse through the dirs and even select a song. It displays the tags in WPS, but won't ever play.
"

I am now going to look at FuzeV2.

[johnb]

Fuze variant 0:

- Samsung card shows the same behaviour as with clip+ -> unusable
- Sandisk Ultra 128GB: worse than with clip+: trying to load a song sometimes seems completely unresponsive, but then recovers. Skipping to next song, it can take 10+ s for the playback to really start.


Volume: going from +3 to +4 playback pauses for a few milliseconds.

[asymsucon]

OK, my battery is now fully charged, so I'll test the variant 0.
Still, it seems that the best way to measure this consumption would be on a used opened unit with a PSU instead of 3.7V li-ion battery.
This battery benchmark will produce different results based on 'wear level' of each user's battery and is thus a poor indicator of how much energy was saved compared to dev build.

From your 30-hour figure, that'd be around 38mW during playback (3.7V@290mAh). That's insanely low!
Just for comparison, Fiio X5II consumes about 25 times more, Fiio X7 over 40 times more!

Good But be warned: at >0 dB it consume more power than current rockbox.

I'm curious. How much more approximately? Having an undistorted 1V RMS into 600Ohm load would be worth sacrificing a bit of battery runtime, but depends on how much.

[asymsucon]

The battery lasted 9 hours and 14 minutes. Not an improvement from regular version.
During the test the UI was somewhat unresponsive.

Playback through folders, -10dB volume, output loaded with 600Ohm headphones (AKG K240)

[Mihail Zenkov]

Still, it seems that the best way to measure this consumption would be on a used opened unit with a PSU instead of 3.7V li-ion battery.
This battery benchmark will produce different results based on 'wear level' of each user's battery and is thus a poor indicator of how much energy was saved compared to dev build.

I do that for myself tests and measuring current. But we have short spike of big power consumption when read from flash or sd so I cant measure it right.

From your 30-hour figure, that'd be around 38mW during playback (3.7V@290mAh). That's insanely low!

I have ~9.5 mA consumption on mp3 playing and in future we can get even less power consumption.

Just for comparison, Fiio X5II consumes about 25 times more, Fiio X7 over 40 times more!

But it have external DAC and AMP so it should consume more. Probably it also can be optimized.

For example - original sansa firmware have poorly optimized flac decoder and consume ~40 mA. At same conditions my latest build consume ~8 mA.

I'm curious. How much more approximately? Having an undistorted 1V RMS into 600Ohm load would be worth sacrificing a bit of battery runtime, but depends on how much.

I will try measure it later. In any case - better have high volume with higher power consumption than unusable high volume with clipping and lower consumption.

[Mihail Zenkov]

The battery lasted 9 hours and 14 minutes. Not an improvement from regular version.
During the test the UI was somewhat unresponsive.

If you have some big lag in UI - you have problems with reading/writing on sd card or internal flash: driver try reread again and again and drain battery too fast. So don't have sense do battery bench if you have this problem.

Probably I found solution to prevent instability - I update links in first my post.

At first better try test and do battery bench without sd card at all (eject it).

[johnb]

BTW, when I copied the build over to the Fuze, properly ejected in Win10 and the unplugged I got (with the first build and the latest) a white screen with
data abort
and I have do a longpress Power ...

instead of being asked if I want to reload firmware.

[johnb]

Now using the -2 version on clip+ var1:
* no issues with internal memory
* drop out on +3 -> +4dB remains
* still the same navigation issues with my Samsung EVO 64GB -> empty dirs

* different Samsung 64GB:
   Startup and scanning disk takes long.  I can play songs from SD. Resume playback after boot (on a flac file) -> starts  to play, pauses, plays, pauses ...
The buffer runs empty (checked in debug). When skipping to the next song, this does no longer happen. Seeking in the song it happens again after playing has resumed.

[johnb]

On buffering from internal vs. external flash, I picked an extreme test case, i.e. a hires file from http://www.2l.no/hires/index.html :
http://www.lindberg.no/hires/test/2L-125_stereo-88k-24b_04.flac
File size : 26 MB (27 275 400 bytes)
Bitrate : 2177 kbps

It plays without stuttering from internal memory, but not from any of my Samsung SDs nor the 128GB Sandisk.

[asymsucon]

johnb,
Do you have any experience with Transcend microSDXC cards in Sansa players? I'm about to get a new card, possibly compatible with this low-power mod 

[johnb]

The max size of Transcend I have is 32GB and atm I don't know in which device (camera, cell phone, dap) these are buried ...
I feel Sandisk is a good bet for larger cards. I will test a different Sandisk 128GB later ...

[asymsucon]

But it have external DAC and AMP so it should consume more. Probably it also can be optimized.

Of course, the power capabilities of X5II and X7 are nowhere near that of Clip+. X5II is rated 2.82Vrms and X7 4.12Vrms. However my point was that while this power is useful for indoor usage with full-sized circumaural headphones, on a portable player it's not as well utilized. Most people listen to IEMs or earbuds on the road, to which DAPs need to put just 1mW to reach dangerous listening levels. In that usecase, the overpowered X5II or X7 is nothing but a hand-warmer and powerhog, burning over 99.9% of consumed energy and only turn that measly 1mW into useable power that travels to the earbuds/IEMs.
Sansa players with their much lower quiescent consumption are thus more suitable for this application, as they can well deliver over 15mW into headphone sources and still consume only 50-60mW in total. 

I will try measure it later. In any case - better have high volume with higher power consumption than unusable high volume with clipping and lower consumption.

Agree 100%.

[asymsucon]

The max size of Transcend I have is 32GB and atm I don't know in which device (camera, cell phone, dap) these are buried ...
I feel Sandisk is a good bet for larger cards. I will test a different Sandisk 128GB later ...

I have only good experience with Transcend cards, but the largest one I have is 8GB. But I'd assume they could work better than Samsung or Sandisk.

[Mihail Zenkov]

* still the same navigation issues with my Samsung EVO 64GB -> empty dirs
* different Samsung 64GB:
   Startup and scanning disk takes long.  I can play songs from SD. Resume playback after boot (on a flac file) -> starts  to play, pauses, plays, pauses ...

Try new build with this cards: http://knk.square7.ch/cvdd2/rockbox-clip+-cvdd2_scaling-3.zip