Microphone Adapter “Line In” Schematics
As I promised in my earlier post here are the schematics for my ‘Line In’ microphone adapter.
Below I show you how I got my Sennheiser EW100 bodypacks to work with my iPhone. I’ve used this and it works for me. I made this schematic after my observations with how the Standard iPhone headset behaves when it was plugged in using the test rig I showed in my ealier Post. The resistor is used to drop the voltage on the Mic line as to tell the iPhone there is a external Mic attached. The capacitor is used to protect the Sennheiser Bodypack from the DC current emited by the iPhone.
Here is my massive Line In Microphone box that allows you to switch from a ‘Pass Through’ to a regular ‘Mic to Tip’ and then a ‘Mic to tip’ that allows the Sennheiser bodypack to work.
Link to a PDF of this schematic
Parts list is below:
S1 – This is a 4PDT Switch that I bought from Mouser Part Number 633-M204201D
S2- This is a DPDT Rocker Switch I got from Radio Shack.
S3- This is a DPST switch I made from a DPDT switch. It is just used to keep the resistor and the Capacitor from feeding back into anything else.
R1- This is a 4.7K Ohm Resistor I got at Radio Shack.
C1- This is a 10 uF Capacitor. You can get one at radioshack or Mouser 140-NPAL50V10-RC
You can get the 4 Pin male Headphone plug at Mouser 171-7435-EX
You can get the 4 Pin Female plug also at Mouser. I used a 161-5435-EX, but 161-7900-EX would be easier to use as you wouldn’t have to put the plug through the case and THEN solder the wires like I had to.
Here is a ‘Mic to Tip’ that allows the Sennheiser bodypack to work only.
Link to a PDF of this schematic
Parts List Below:
R1- This is a 4.7K Ohm Resistor I got at Radio Shack.
C1- This is a 10 uF Capacitor. You can get one at radioshack or Mouser 140-NPAL50V10-RC
You can get the 4 Pin male Headphone plug at Mouser 171-7435-EX
You can pick up the 3 Pin Headphone at Radio Shack or Mouser. 16PJ106-EX
Credit goes to Jesse from Bent-Tronics.com with regards to the capacitor idea. I came across his post when I first ran into frustrations with getting the Sennheiser body packs to work.
7 Comments
Leave a Reply
Subscribe To My Blog
Awesome! I've been trying to do this myself. Why is it that there are no commercial products that provide a line in option on the iPhone? Thanks for doing this.
On the 171-7435-EX, how do you connect to it? It seems like it would be a royal pain to soldier to it.
It’s not to bad to solder. Just get a small diameter solder tip.
The cap is for DC blocking.
this is great information. and it works great for me.
here a bit of what i found:
i tried to connect a small pre-amp to the ipod but no signal was recognized, using voice memos.
than i tried connecting ipod and laptop to my mic at the same time. and when ever i plugged the laptop in too the ipod was also able to receive a signal.
i am not sure what is going on. but your solution works super.
i also noticed that the mic ring on the ipod touch delivers 2.5 volt.
i am now able to connect a contact mic to the ipod touch without any opamp or preamp.
thanks.
stephan schulz
would you have a project to bind a guitar?
To get it to work with an iPhone 4 and a guitar you have to change the value of the R1 resistor to about 1K. Otherwise the iPhone wont detect that you’ve connected an external microphone.