The Stagg comes with an active pre-amp powered by a 9V battery. So far these seem to have eternal life, even when it is of some obscure brand. But I have also read reports online that claim very short battery life. So just to be sure I have put a spare in the gigbag…
On both my Staggs the electronics work pretty well. The headphone out is really handy when practicing late at night and the MP3 in is nice for playing along your favourite tracks. The Stagg has two piezos (one under each bridge foot) that have an adjustable potmeter. A small adjustment can have a great effect on the sound so be careful!
The very first thing I did on my black Stagg was shielding the electronics. The Stagg company did not bother with this and it is easily done by yourself. You just need some aluminium or copper tape, a sharp pen knife and some time. I did not think of this myself but found a complete tutorial online: see it for yourself on Flickr. Thanks for sharing your pictures mateybass!
I followed the tutorial picture by picture. I did try the foam under the piezos on the black Stagg but did not hear any difference in sound whatsoever. The endpin rattle I have solved another way. You can read about that here and here.
Below a few pictures of the shielded endpin cavity. The pre-amp cavity looks the same.
Stagg EUB modifications 