Special thanks to my friend and teacher Mike McConville (http://mcconvilleguitars.blogspot.ca/) for referring one of his customers to me. It saved the owner of this beautiful vintage Gibson D-45 some considerable travel time.
This guitar has the acoustic B-Band under saddle pickup system installed. It developed some issues a while after it was installed, in that an audible and annoying popping sound was heard whenever the lower bought was jostled or knocked. A tricky thing to pinpoint in the modern printed circuit board preamp systems...
You can see some of Mike's handywork here. D-45's of this era came with the tone-sucking adjustable saddle, which had two threaded posts at either end of the saddle. Mike used a piece of matching rosewood to fill the space then routed in a conventional saddle, hand made from a bone blank. This is the only way an under saddle pickup system can be installed in these guitars, not to mention the fact that the guitar sounds 100% better!
Here is a view from under the saddle. You can see the B-Band cable has been routed through the threaded post that previously held the saddle adjustment ~ clever! It did move around quite a bit inside it though, so I carefully inserted a small piece of cork to stabilize it in the hole.
A preliminary check revealed no loose or shorting connections or electrical anomalies. Considering the noise was generated from the lower bout, it was time to open the preamp ~ which in this case is attached to the back of the jack...
After removing the assembly I left it connected to see if I could coerce the unit itself to make the popping noise. It didn't take long, and the culprit turned out to be the battery connector that housed the red & black wires from the 9v power supply. I noticed someone had put a drop of super glue on the connection, but it obviously didn't fix the problem.
After a little more wiggling I noticed that the black wire sat firmly in place, but the red wire shifted slightly (approx 1/32") within the connector housing. With the amp on I wiggled it again and sure enough it popped every time. The red wire wasn't crimped tight enough within the connector, and it moved just enough to cut power momentarily whenever the guitar was jostled. No wonder the owner was frustrated!
Super glue to the rescue! A little drop in the hole at the top and back of the black connector did the trick, then the connector itself was cleaned and crimped slightly tighter. Certainly something to check for when installing or inspecting these systems.
