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Anyone want to get a Hidizs AP200 and test it with a low impedance load?
Cowon Plenue J:
Does anyone have the fiio x7 markii and fiio x5iii to test with the shure se846 and post the fr curve here?
Xiaomi Redmi 4A 4G:
Should be 2.8-ish Ohms if I'm right, shouldn't it? Or 4.5? I'm a bit confused right now (and tired).
dunno.. guess it depends of Triple.Fi impedance curve (and supposing flat output impedance in the source, which is usual).
you are used to test sources with Triple.Fi, and so you are able to calculate it.
after testing and watching others' tests of xiaomi phones, noticed that those equipped with mediatek processors, use to have an output impedance around 15 ohms.
while those equipped with qualcomm snapdragons, are around 0.8 ohms; at least, QCs from 6xx series and higher. maybe output impedance of 4xx series is higher.
compare a note 4 mediatek (17 ohms) with note 4x snapdragon 625 (0.8 ohms):
my future phone will be a QC for sure..
Calculated it again and it should be 4.5 Ohms.
Anyway, it's not close to 0 or 1 Ohms. And there's some other weird stuff going on with the audio playback, such as a noise floor that changes its intensity depending on the music's dynamic, along with some quiet crackling whose intensity changes as well depending on the dynamic (noise gate? Bad power supply and distribution? Or just audible DAC artifacts? Whatever it is, it leads to a slightly strange presentation).
then, another audio gear to avoid. thank you!
Could you have a bad copy?
Me? I don't think that this is the case.
But I also think that Xiaomi didn't really expect their users to use super sensitive multi-BA in-ears; it's a budget-oriented smartphone after all (but a really good one besides the audio part, heck it's even got a magnetic compass for proper GPS orientation, something I really didn't expect to find in a budget model).
I btw experienced similar behaviour with my Redmi Note 3 Snapdragon but didn't bother to do proper testing yet..
High output impedance isn't really unheard of in phones. Even iRiver thought high output impedance was a good idea with their first Astell&Kern, they proudly advertised that it had the same output impedance as hifi speaker amplifiers (over 20 ohm).
And these are Hi-Rezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz engineers we're talking about.
=> ~ 1.6 Ohms. Hiss-free even with extremely sensitive IEMs.
Boy, would I like to see outputs to BA iems out of TOTL Astell&Kern DAPs, Opus #2, or the Lotoo Paw Gold. That would be great if somebody measures can get review samples to make comparisons in iems response differences between them.
FiiO Q1 MkII (single-ended 3.5 mm TRS):
Amp, No Load:
DAC-Amp, No Load:
DAC (Line Out), No Load:
... and the same measurement with a different graph scaling:
=> ~ 1.2/1.3 Ohms output impedance, single-ended. Basically hiss-free (single-ended) in pure amp mode even with super sensitive IEMs such as the SE846 and KC06A; some very mild hissing when used as a DAC-Amp. Noticeable hiss over the balanced 2.5 mm TRRS output. The thing I probably love the most is that they implemented a digital volume control.
Very interesting. Focused FiiO Q1 MkII because of its price together with digitalised volume control, dac/amp + amp capabilities, and balanced output chance (i don't own any balanced gear yet).
pity its output impedance is over 1ohm (not too high though) and balanced hissing.