Would the hardware of a Sansa Clip allow Mic recording through headphone out?

[FranciscoB]

Oh, so that input now works as most mobile phone inputs do, correct?

What about the 22nf cap? Is it to block dc current? I dont see it in the photos, maybe the smd is part of the input jack?

[rocksnoc]

the cap:




the cap is to block DC

I measured:
- 1.5 V DC between battery negative terminal an jack "GND" (UNEXPECTED!)
- 0.0 V DC between battery negative terminal an mic GND
- AC voltage - I can't remember... (but about 2.5V AC ?!)


the 3.5-4pin-jack :
There are two different types of 3.5-4pin-jacks (A and B) on the market with a different pin assignment...
picture: german wikipedia: http://de.wikipedia.org/wiki/Klinkenstecker#Stereo-Stecker_mit_Zusatzfunktion_.284-polig.29

I tested a motorola 3.5-headset with mic (typ B) and it works fine: stereo + mic!


test recording:
If somebody sends me a licence free audiofile (provided from the RockBOX poject) I will share a test recording of it here.

[FranciscoB]

Oh, I was only thinking "smd" and didn't notice the ceramic capacitor 

You could use something from Archive.org, for example:

http://archive.org/details/opensource_audio

You can only record in mono, correct?

[rocksnoc]

sound test:

I played a test-wave-file from 1-22kHz:


The frequency response:
- low frequencies are cut off because of the cap
- high frequencies are baffled

Ideal would be the same amplitude over all frequencies!


Zoom to low frequencies:


- there is a minor DC proportion on the input

[LADave]

How do you explain the HF rolloff?  Is the Clip doing some kind of equalization, is it in your input source, or is it the mic you are using?