Oct 12 2009

Project: Shielding, re-wiring, and new pickups…

by Josh
The body cavity was completely unshielded, as you see here.

The body cavity was completely unshielded, as you see here.

Over the past week, John and I have worked on a new project: fixing up my 1999 Made in Mexico (MIM) 60’s re-issue Fender stratocaster.  The start of the issue was a persistent, irritating hum that emanated from the guitar when my hands were off the strings.  It was made perfectly clear that some hum is normal with single coil pickup guitars, but John was convinced that some improvement could be made.

Shielding

Shielding a guitar is the process of adding material to protect the wiring in the body of the guitar from offending radiated energy.  More information can be found at this handy page at Catalina Guitars.

The shielding tape is applied to the back of the pickguard.

The shielding tape is applied to the back of the pickguard.

John informed me that shielding my guitar would eliminate some of the hum, so I purchased some conductive shielding paint and conductive copper tape.  The process of shielding was the most simple that we undertook during this project.  Remove the strings of the guitar, take off the pickguard and remove all of the controls.  The shielding paint indicated that you needed to apply three coats to the interior cavities of the guitar, allowing 24 hours between each coat.

Shielding paint applied to the body cavity and the face of the guitar.

Shielding paint applied to the body cavity and the face of the guitar.

While the first coat of paint was drying, John applied the copper shielding tape to the back of the pickguard by cutting strips to fit the contours and smoothing it as he went.

Re-wiring

Upon removing the pickguard, John discovered that my guitar had cheaper, plastic coated wires hooking up the internals.  We got hold of some cloth wrapped, wax coated wiring from our local guitar shop.  The wax coating removes any internal air space surrounding the wire, which eliminates the chance of microphonic feedback.

We had originally planned on rewiring the guitar by following this guide that we found, however after a failed attempt on a guitar John was working on and some difficulty getting the materials to solder together properly we opted to cut our losses and rewire the guitar using Fender’s stock wiring diagram and the improved wiring that I mentioned above.

The new wiring installed, this was not the final configuration.

The new wiring installed, this was not the final configuration.

Neither John or I are experts at soldering, but we got everything attached back together without any major issues.

New Klein Pickups

The final step was installing the new S-5 Klein Scooped Mid Range Stratocaster pickups.  Using the above wiring diagram, we were able to install these pickups very quickly.  These pickups are also wax coated (referred to as wax-potting) in order to reduce vibration and microphonic feedback.  I intend to post more on this topic soon, both John and I were very impressed with the results.

The new S-5 Scooped Mid Klein Pickups installed.

The new S-5 Scooped Mid Klein Pickups installed.

One additional benefit of the Klein pickups (this particular set, anyway) is that the middle pickup is reverse wound.  This makes the neck/middle and middle/bridge switch settings act like a humbucker pickup, which totally eliminates hum in those two settings.

I don’t have much experience to draw from, but John does and he considered these pickups to be some of the lowest noise (hum/buzz) of any single coils he has heard.  That’s good enough for me!

Neck Modification

The sanded neck, leading to the headstock.  Notice the satin appearance.

The sanded neck, leading to the headstock. Notice the satin appearance.

I originally got this guitar used and there were some dings in the neck.  I showed this to John, and he quickly conjectured that going over it with fine grit sandpaper would even out that sticky gloss polyurethane finish and get rid of the irritating dings.  Some 400 grit sandpaper and some fine steel wool did the trick!  You can see in the before-and-after video below that it looks satiny and it does play much faster than it did before.

Testing and Final Results

Once we got all of the shielding paint dried, the newly rewired hardware installed to the shielded pickguard, and the guitar restrung it was time for testing.  We found that we had succeeded too far in our shielding efforts, and we had a small issue with the jack touching the shielded cavity and

grounding out.  After several attempts to fix it, we opted for the low-tech solution of applying some electrical tape at strategic locations in the jack cavity and the process was complete!  John donated some aged vintage pickup covers and knobs to my cause for no other reason than they looked cooler (I agree!).

We put together a before and after video, which John has graciously hosted on his YouTube account.  John is doing the side-by-side (including the nice riffs to illustrate things) and the pictures in the middle are from our build process:

In the end, I consider this project a wild success.  I learned a lot about the inner workings of my electric guitar, we both discovered the excellence that is Klein pickups, and my guitar is nearly hum free.

John and I are going to embark on more “Do It Yourself” style projects like this, so expect to see more of this as time goes on!