DIY iRig using SMD inside the guitar connector

[Bluetooth]

Hi
I have made two "iRig" preamps for iPhone using SMD components and placed it inside the mono Jack guitar connector.
I have used the diagram from this post: http://www.diystompboxes.com/smfforum/index.php?topic=95461.0
I have used BF545B as JFET in a TO236AB and else plane SMD components in 1206 housing.
I have used a 50 cm iPhone headset extender cable and cut it in half.
The job requres some fixing posibilities, magnifying glass and a huge portion of patience.
You can see the pictures of the result here.
Total picture of the cable:


The mono jack with the preamp inside:


Close-in of the preamp, The two resistors to the left and right are on top of the parallel condensators. You can see the JFET to the left and the input condensator to the right.
The components are soldered to a small part of a CStrip 0.4mm


In general it is working fine but sometimes I experience that a noise suddenly start and last for about 5 seconds and then it is gone and it works fine onward.
Good luck