[fiddler]

  Nah, I've already said too much.  I'll bow out, now - before I get myself into further trouble.

 

Didn't mean it like that - I mean I'm actually looking for people with measuring equipment to add to the database... so your contribution would be genuinely appreciated.

 

[fiddler]

I've made necessary adjustments to the instructions and put the link to the database, and also an explain as to why output Z matters all in a handy little Wiki. Check it out:
 
http://source-output-z-for-cans.wikia.com/wiki/Source_Output_Z_for_Cans_Wikia

 

[ForceMajeure]

So I have made some measurements. Using a UNI-T 139C multimeter, a 3.5 to 3.5 cable with a ground resistance of 0.1 ohm and a left and right resistance of 0.4 ohm each (overall 0.5ohm cable resistance for a single channel measure) and a 19.8 ohm resistor. I have used a 100hz sine tone (i also tried with 1000hz sine tone and got the same results).
 
I have measured 3 different sansa's clip zip at the same volume to make sure I have consistent results, I also made sure to not use high volumes to avoid distortion/clipping. All the results are with the cable resistance subtracted.
 
I also measured some old phones for fun, If I find other devices around I will measure them.

Device	Zoutput_Impedance	Vin	Vout	R	Rcable
Samsung Galaxy s6	1.46	0.04803	0.04371	19.8	0.5
Meizu m2 note	34.11	0.0815	0.02966	19.8	0.5
Dell Inspiron 7548	22.96	0.1973	0.0903	19.8	0.5
Dell Inspiron 1545	61.04	0.1573	0.03829	19.8	0.5
Nokia n97	16.38	0.2766	0.1493	19.8	0.5
Sony Ericsson w995	12.73	0.1453	0.0871	19.8	0.5
Sansa Clip Zip	0.30	0.3901	0.3749	19.8	0.5

 

[fiddler]

Very nice, thanks for your contribution.

 

[ForceMajeure]

While cruising in the Cayin C5 amp thread I found the output impedance of this amp confirmed by a Cayin representative: 
 
http://www.head-fi.org/t/729545/the-new-cayin-c5-portable-power-house/105#post_10814903
 

Cayin C5 output impedance is 0.032 ohm ​

 

I wouldn't be surprised if the Cayin c5 dac also have the same output impedance.​

 

[ForceMajeure]

Here are a few measurements made by goldenears, can be found scrolling down the page
http://en.goldenears.net/index.php?mid=KB_Columns&document_srl=1389
 
Also according to Brooko's Aune x1s review 
http://www.head-fi.org/products/aune-x1s-32bit-384khz-dsd-dac-headphone-amplifier/reviews/13990
 

	Aune X1s	Audio-gd NFB-12	iFi Micro iDSD
Cost (approx.)	USD 249	USD 235	USD 499
Dimensions	145 x 171 x 45mm	160 x 260 x 45mm	68 x 180 x 25mm
Weight (unit only)	880 g	1320 g	300 g
Outer Shell	Anodised aluminium	Brushed aluminium	Anodised aluminium
Input power	Walwart + 12V adaptor	Walwart (internal adaptor)	USB + has internal battery
Input coax	24 bit / 192 kHz	24 bit / 192 kHz	24 bit / 192 kHz
Input optical	24 bit / 192 kHz	24 bit / 96 kHz	24 bit / 192 kHz
Input USB	32 bit / 384 kHz	24 bit / 96 kHz	32 bit / 768 kHz
DSD (DoP via USD)	Up to DSD 128	Not supported	Up to DSD 512
Frequency response	20 Hz – 20 kHz +/- 0.5 dB	20 Hz – 20 kHz  +/- 0.2 dB	Not stated
Dynamic range	126 dB	118 dB	117 dB
THD+N	-110 dB @ 1 kHz	Not stated	< 0.008%
IMD+N	-110 dB @ 19KHz & 20KHz	Not stated	Not stated
Stereo crosstalk	-112 dB	Not stated	Not stated
Line Out Voltage (fixed)	2.1 Vrms	2.25 Vrms	2 Vrms
Line Out Voltage (variable)	Not supported	Up to 5 Vrms	Up to 5 Vrms
Headphone out impedance	10 ohm	2 ohm	< 1 ohm
Output power (1)	1550 mW into 16 ohm	3500 mW into 25 ohm	Up to 4000 mW @ 16 ohm
Output power (2)	1200 mW into 32 ohm	1800 mW into 50 ohm	Up to 2000 mW into 32 ohm
Output power (3)	200 mW into 300 ohm	300 mW into 300 ohm	Up to 212 mW into 300 ohm
Output power (4)	100 mW into 600 ohm	150 mW into 600 ohm	Up to 106 mW into 600 ohm
Digital filters	3 (front panel)	9 (internal jumpers)	3 PCM and 3 analog (switches)
Gain switching	Not supported	High and low	9 settings (3x3 options)
USB support	Driver required (Windows)	Standard Windows Driver	Driver required (Windows)

 

[fiddler]

I've added it to the reddit /r/headphones database, thanks!

 

[nieuzytek]

smartphone LG Nexus 4 - 3 ohm
 
laptop Asus X550, Realtek ALC 277 - 70 ohm
 
PC Dell Optiplex 790, Realtek ALC 269Q - 25 ohm