[Galaxy S II General] pspilot:
Hmm ... maybe Yamaha messed it up, but they are no complete beginners, especially when it comes to quality mobile sound. I have a Pocketrak W24 here, a wonderful mobile 2-channel field recorder. The quality is really good, up to 96kHz/24Bit PCM and, they run it 18 hrs. on a single AA! It's no mobile phone, agreed, but it has alot of quality digital audio inside. Though ... now I mention it, it is a wonderful recorder, but the control headphone out IS a bit low volume, one of the rare critics when you read reviews about it. Maybe Yamaha can do all but good headphone amps :D.

Well, looking closer at the manual meanwhile, it shows that the amp is fixed powered by 'VBat', whatever that is (usually the unregulated battery input, which is hard to believe in that case). But there is still a AVdd and other voltages. The pity is, that the manual is not the exact schematics I hoped it would be. It only mentiones parts that are interesting for the service.

Unfortunately I have no idea about these AMOLEDs. I applied some LCDs and thought the AMOLED is similar for the average consumption. But obviouosly they can be beasts when bright white. A friend even recommended to actively search for apps, that allow to be set up as 'dark apps'. No black letters on white, but vice versa etc. I never thought about it that way.

On the headphone amp part of the sound chip. I attached a snippet of the datasheet (JPG). Unfortunately I don't have the full data sheet yet, lots of details to apply the chip are missing. I'm not 100% sure what the pump does, but it should be related to the amp. What else are the lines into the amps?

You're absolutely right about the clock quality. Alot of times it's a drama and people don't consider it, because "it's all digital for heavens sake" ...

Your measuments are telling so and I have no idea, how good the Yamaha chip is working on the clock, neither how good the clock is indeed. But in the moment, that seems to be at least MY second important problem :). But it is important of course. That's why I would be curious about the USB-output (I mean the switched one, the analog audio on the USB data lines). I finally got some micro-USB plugs and want to build me a cable ... time, time, time ...

ASRC - Advanced Simulated Radar Client ... no, joking, confusing people here :D. Basically it's the same as with the clock. No idea how good their sample rate converter is, but I again tend to trust Yamaha more than Samsung :). In other words, IMHO the chip is mostly better than the implementation.

That noise when switching CPU speed or whatever is really a bad flaw. Then again, you have to have some power for the headphone. And even a PLL can be seriously messed up with an unstable or rather noisy supply.

Yep, I don't see any mode switching. It's a pure load situation, that changes the level. If the noise remains equal with different loads, that's good and bad news. The good news is, that the power amp supply is obviously not injecting the noise or it would be load dependent. The bad news is, the noise is produced much earlier and influencing all parts of the chip then.

Please, thanks!

On a side note: I received that WiiO E3 tiny headphone amp ... well, its crap :rolleyes:. They totally messed up the linearity, the part boosts the lows, very unpleasant. So its no way to get a better sound, only a bit louder. But now I'm 'on fire', so I ordered their E7 which is actually not only a (hope fully better) headphone amp, but has also an own digital interface via USB. Appearantly they even use that widely respected Wolfson DAC, so I'm curious. As I said, for a mobile solution it's too clumsy, only my 2 cents of course. I'd never carry it always along with my mobile :rolleyes:. But if its quality is right, it's still an interesting little addition for alot of occasions. On the home PC (hey, their sound interfaces are mostly horrable) or a laptop. Anyway, for 70€ I gave it a try and Amazon has good a return policy :D.

Is that about the device you're thinking of?

Oh my, I'm filling again the page and I didn't post my latest headphone amp results yet. On to that now ...