Experiencing a frustrating hum from your acoustic guitar? I recently encountered this issue, and after some troubleshooting, I traced the problem back to either the pickup itself or the wiring leading to the preamp. Limited by space and tools within the guitar’s cavity, I opted for the most straightforward solution: replacing the pickup. Fortunately, this worked, and the annoying hum disappeared completely.
It’s possible that the original wire had a shielding problem, as suggested in this helpful answer regarding guitar hum issues. However, without being able to thoroughly inspect or shield the wire in place, replacing the pickup seemed the most efficient approach. In the past, for similar hum problems in electric guitars, I’ve successfully used copper tape to shield the inner cavities. Interestingly, I noticed there was no shielding at all on the endpin jack, which some sources online suggest can also be a source of unwanted hum.
Here’s a look at the old pickup I removed:
Seeking further insight, I contacted Fishman directly about the hum. Their response pointed towards a potential issue with the under-saddle pickup element itself:
It sounds like the under saddle pickup element may be faulty. Usually if you touch the endpin jack and the hum goes away, it is a shielding problem within the pickup element.
The email from Fishman also conveniently included a recommendation for a retailer selling the replacement part I needed. Initially, I was skeptical. Visually, the foil on my existing pickup appeared intact, although I acknowledged that a very small, hard-to-spot tear could still be the culprit. Then I recalled a recent string change where the bridge popped out. It occurred to me that I might have inadvertently damaged the pickup while re-installing the bridge.
Taking a chance, I decided to order a replacement Fishman pickup. The crucial step was to measure the width of my current pickup to ensure the new one would fit correctly in the saddle slot. Mine measured 1/8″, so I ordered the corresponding part from the provided link. Despite opting for the most economical shipping option, the new pickup arrived within a few days.
The installation process involved a slightly tricky moment: soldering the new pickup’s wire to the mini-jack that connects to the guitar’s internal preamp. This soldering had to be done with the pickup already positioned in the guitar, as the jack is too large to fit through the pickup hole in the bridge. While I had performed similar tasks before on other guitars, it still required a bit of careful maneuvering in the tight space. Once soldered, the rest of the installation went smoothly. Despite being slightly shorter (by about 1/32″) than the original pickup, the new Fishman pickup delivers an even volume across all strings, and most importantly, the hum is completely gone. Replacing the Fishman pickup effectively resolved the hum issue, highlighting that the pickup itself can indeed be a source of such problems in acoustic guitars.
