Support and General Use > Hardware
Sansа Clip Zip - Improve battery life
Mihail Zenkov:
Yes, we should check 96Mhz PCLK with divided DBOP as you mention early.
Also I think we should try same but with increased delays in dbop-as3525.c.
oid_maps:
--- Quote from: saratoga on January 02, 2015, 11:17:01 AM ---I think devices with a wheel will boost whenever the wheel is used. Here is one more build:
http://web.mit.edu/mgg6/www/rockbox-fuzev2_64MHz_2.7z
--- End quote ---
I just put this on the fuze v2 -- since it seems to be the latest build -- but then, when switching to "hold" and coming back, device _sometimes_ does not come back. Reset by holding power-button for several seconds is necessary.
Hangs also on keypress in file browser. Seems to _completely_ hang, since sometimes LCD gets blurred, like when you just leave electrical LCD-contacts open.
Hm ..
By the way: The up to date patches? Since I usually build from source and don't use precompiled images. (I also add one very small minor patch, which has to do with radio tuner region settings.)
saratoga:
The latest patch is here:
http://gerrit.rockbox.org/r/#/c/1062/
Here is one other build, which is similar to the others (clock changes) but no boosting:
http://mit.edu/mgg6/www/rockbox-fuzev2.7z
keyb_gr:
I can basically confirm the effect of the sound patch on my new Clip+ (made late 2014):
--- Quote from: Mihail Zenkov on December 06, 2014, 12:03:42 PM ---WARNING: this patch may improve battery life and sound quality :)
Sound quality checked with RMAA and emu-0204.
[...]
No load, 0dB.
Without patch With patchDynamic range, dBA: 93.395.0THD, %:0.0160.0037IMD, %:0.0190.0065
--- End quote ---
A SB Audigy FX said 0.015% THD with a Jan 9 build, with one from Jan 23 (the sound patch was checked in at Jan 19) it's 0.0038%. (Volume +3 dB, RG pre-gain -3.0 dB, no RG tags on files.) IMD+N is noise limited but I don't see any discrete components above -90 dB, pretty good. DR showed about 93 dB(A). Curiously, crosstalk is now up to -70 dB across the band, while it reached 90-ish dB before with some increase towards the highs. If that's purely internal and has nothing to do with headphone xtalk levels, I can live with that.
Oddly enough, my old (late-2010 production) Clip+ already showed fairly low distortion with the "old" build, but its noise was much higher (by 12-13 dB). Shouldn't be when both are using the same RB build and configuration, right? Old results show 0.016% THD though, so possibly the chip incurred some damage in the meantime (maybe the poor thing got zapped one time too many). Output volume isn't any quieter than it should be, it's just noisier.
BTW, RMAA results in 48 kHz mode look like crap because the pitch is way off... almost +0.8%, that's close to classic Clip pitch bug territory. Looks like the PLL settings for that one could still use some tweaking. (I was using 48k because I found that both the Audigy FX and my old onboard ALC262 would catch an unduly amount of extra noise recording in 44.1k, easily 7-8 dB more even when compared to 16/48. I suspect some jitter or aliasing issues. Ultimately I ended up resampling the 48k test files in software so I could play them at 44.1 while recording at 48.)
Has the "turn off USB while not connected" patch been checked in yet (or how well does that part work)? I can't really tell from this thread. Saving 5 mA which are basically being wasted would seem quite attractive.
saratoga:
Yes, that is committed.
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