[HiFiChris]

iPhone 4 with InEar StageDiver SD-2 as load:
 


 
 
Will eventually repeat with the T.F10 as I haven't saved that measurement back then. Output impedance is quite spot-on 1 Ohm, so well suited for multi-drivers with capricious impedance response. Sound output is neutral and clean, and the amount of hiss isn't bad either.

 

[HiFiChris]

iPod Nano 1G unloaded headphone output:
 
 

 
 
 
iPod Nano 1G loaded with Triple.Fi 10:
 
 

 
Caps in the audio path cause sub-bass roll-off with low impedance headphones. Output impedance not the lowest either.
 
 
 
Nano 1G LOD:
 
 

 
Channel imbalance, high distortion - obviously not Apple's best product for using the Line Out.

 

[HiFiChris]

Leckerton UHA-6S.MKII (loaded + unloaded):
 
 

 
Output impedance ~ 0.4 Ohms, hiss-free in low gain mode (though my unit is gain-reduced, so I cannot speak for the standard version's hiss levels).

 

[HiFiChris]

Sony PlayStation Vita with Triple.Fi 10:
 

 

[HiFiChris]

AGPTek C05:
 

 

[HiFiChris]

AGPTek C1:
 
No Load:


 

Triple.Fi 10:
 



iBasso Burn-In Dummy Load (BEWARE - DIFFERENT SCALING):
 

 

[HiFiChris]

Elekit TU-HP02:
 

 

[HiFiChris]

iBasso DX80:
 

 

[HiFiChris]

PGA2311 Pre-Amplifier (No Load):
 

 

[HiFiChris]

Cowon Plenue D:
 

 

[HiFiChris]

HiFiMe 9018d DAC:
 
No Load Digital Filters:
 

 
 
Triple.Fi 10 Digital Filters:
 

 

[HiFiChris]

Shozy Lancea:
 
No Load:
 

 
So that's what the "DSP" feature is all about - it shapes the frequency response, making it loose its neutrality. A DAC/Amp should output a flat, neutral signal. The Lancea does not. From an objectivist's point of view, this is no good thing. And this colouration can be already heard. 
 
 
Loaded (Ultimate Ears Triple.Fi 10):
 

 
-> pretty high output impedance, not well-suited for multi-driver in-ears with non-flat impedance response

 

[reginalb]

So...I don't think that going through the line in on my docking station on my desktop works all that well for this. Here is the headphone out on the laptop, looped back in to the line in on said dock:
 

 
And then my ZX1:
 

 
Note the scale on the right, I am zoomed WAY out. I have used both of those outputs. They do not have a 20dB spike anywhere, haha. 

 

[HiFiChris]

Have you disabled any DSPs and applications (lower right corner in the status bar and the Windows control panel) that could cause this?

Have you tried using a different source device than the Sony?

 

[reginalb]

  Have you disabled any DSPs and applications (lower right corner in the status bar and the Windows control panel) that could cause this?

Have you tried using a different source device than the Sony?

 
Just the Sony, and the headphone out of the laptop that I was using to measure with it. I will check for any processing that might be going on.