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Posts by alphaman

Yes. I wrote to Amazon relating my poor experience with this product. Maybe others did, too. But even if Teclast or Mp4Nation products were continued to be distributed by the major U.S. outlets (Amazon, etc.), the customer-rating/feedback system would have -- by design -- "done them in" if they did not get their act together v. quickly. It may not matter as Mp4nation have their own USA store ... as frenchbat noted above, "Cheap is cheap, and the business model is...
Thanks Tronz!   For all intents and purposes, we should  include in this discussion ...   iPhone (as Teclasl, MP4Nation devices are somewhat similar) iPod Touch  (and older/'legacy' products like iPod classic).   Anyway, I should answer my own question! ...   QLS QA-350 -- the external charger gets quite warm while charging, but the unit runs cool. I've finger-tested the ICs inside while the unit has been in use for 1hr+ and they are all cool....
What are you folks using for C6 (which Tangent suggests as NP0 or C0G)? I'm using CAP CERAMIC 10PF 50V NP0 1206 (Digikey 399-1192-1-ND; Kemet C1206C100J5GACTU), which is a $0.14 part.    Not sure whether upgrading this to something better will make much of a diff. I noted Styroflex above, but I have none that go this low in capacitance value, e.g., 10pF. Any thoughts? Thanks!
   In a possibly vain effort to determine the Teclast T-51/S:Flo2's poor reliability issues -- a device known to run quite warm -- I want to query the general Head-Fi DAP-using crowd ...   How warm during use (playing music)? How warm while charging?   I don't have an iPhone, iPod Touch or any of the new-style cell/mobile phone devices (similar to the S:Flo2/Teclast device). How do warm do, e.g., the iPhone, iPod Touch, etc. usually run?  If you own/have...
lee730: FLAC requires more processing from the Rockchip DSP, so 4hrs is not unreasonable. What takes HUGE amounts of power is DC-DC switching (step-up power conversion). This is one main reason the unit runs so warm (and may very well be root agent for this device's horrible reliability). BTW ...  I don't have an iPhone, iPod Touch or any of the new-style cell/mobile phone devices (similar to the S:Flo2/Teclast device). How do warm do, e.g., the iPhone, iPod Touch,...
  It has been a while since I built the unit, but I'm pretty sure I chose HQ metal film Rs ... mostly Panasonic and Vishay. But, since you brought it up, I may experiment with other brands.I agree that signal-path Rs must be of v. HQ. Did you mean the AD827 (and not OPA827)?    
Thx for reminding me of this OPA ... no I haven't, tho' I have it in my parts bin. (Feedback on this soon ...) About the AD8610/20 ...  GOOD: Pace, rhythm, acceleration and timing (aka PRaT) is among the best (like AD825). OK: Detail, image focus BAD: Graininess, unrefined, "loud" (as opposed to fwd or lively) sounding. I'm not sure there is any way to tame these BAD qualities. Certainly, my added bypassing, noted above, didn't help. There is also op-amp snubbing, which...
  I haven't fully explored this thread (much less this forum on the following topics) so please forgive any waste-of-bandwidth. Anyway ...   WRT tweaking v2 ...   (1) How much extra benefit can be obtained further bypassing (beyond Tangent's topology/schema) various opamps (either buffers or main)? E.g., for the main L/R opamp, I am using 10uF BlackGate electros + AVX 0.1uF PPS smd's. Not a whole lot of room, but the electros have improved SQ.   (2) C6 (NP0...
The AD8656 is a relatively modern (= mostly unknown) device from Analog Devices and is very nice! It's used in the line-out section (after WM8740 DAC) of QLS QA-350 DAP. The newer QA350 v2 uses AD8397 in the headphone-out (HO), replacing v1's MAX9722A. I never use the HO so I can't comment on that. I did experiment with rolling various OPAs, including LT1364, but still like the stock AD8656 best in the QA-350. QLS's Clark Chen has noted that AD8397 can sound better (than...
No argument there! Hmm...If crash freq. increases for you, I would assume the worst. Before that fateful day, maybe you could hock it -- with full disclosure of issues, of course! ;) ?? Or better yet, gift it to a friend or "enemy". :-) LOL!    
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