A few years ago I got myself a used Epiphone Les Paul Special II for about 70€, which was really cheap. Then a few weeks ago I wanted to try out modding guitars, so this Les Paul was the designated „vicitim“ for my experiments. Before the modding it looked like this:
So I got myself a set of cheap „zebra humbuckers“ at Amazon and tried to replace the pickups.
Well, replacing a pickup is not rocket science, you just remove the old ones and put in the new ones, just need to solder a bit of wires. The new pickups offered the possibility to split the 2 coils, but since the stock setup has no switches for that I just put some shirinking tube on the wires for the split so that hey are isolated. After the wiring was done the electronics looked like this:
The green shrinking tubes are there, everything in place and it worked as expected. Sounded quite good for a cheap set of pickups.
Problems and the Ohm’s law
A few days later when practising I noticed that the nut of the output jack was a bit lose so I tried to tighten it. And with his actions problems occured. The neck pickups seemed to be gone, only audible in high gain settings. I checked with an Ohmmeter and found out that the resistance between the 2 pins of the output jack was about 530 Ohms in maximum volume setting. I measured the pickups and one had 7 KOhms, the other around 15 KOhms.
Lookiing at the wiring diagram for the Les Paul Special II it showed that on maximum volume setting we have a parallel circuit between the pickup (7 KOhms) and the volume potentiometer (500 KOhms), so according to Ohms law the resulting overall resitance should be 6903 Ohms. But I still got only 530 Ohms. Yeah, something got messed up.
Discussing this phenomenon with colleauges it became clear, that the best choice for me is to do the wiring again from scratch.
So, since I had to replace everything I ordered push-pull potentiometers, so that I can take advantage of the split-coil possibility of those humbuckers. The parts arrived last week and today I had the time to solder again. This time it was easier to solder, because I did this outside of the small compartment in the guitar body and then put the parts in. Lesson learned, don’t solder inside that small space. Also for soldering the ground wires to the housing of the potentiometers my usual electronc soldering iron had not enough thermal power, but luckily I have a soldering pistol with 100 Watts for this, so soldering was not a big problem.
The potentiometers are deep down in the body, the small rectangular towers are the push-pull switches. So if the switch is pushed in I have a humbucker setup, if I pull the potentiometer knob then it creates a short circuit on one coil of the humbucker and I have a single coil setup.
Since the old knobs almost fell off the old potentiomters I also ordered new knobs.
And the whole guitar hanging on my wall looks now like this.
So after everything was assembled I plugged in the amplifier and started to try out. Perfect sound, both pickups are there and sounding quite good. Here are some sound samples, just played the open strings.
Neck pickup as Huumbucker
Neck Pickup as single coil
Bridge pickup as humbucker
Bridge pickup as single coil
At the end I’m quite satisfied with the result. Now I have a very special Les Paul Special II and it has a few more sound possibilities than before. And I got my feet wet in the topic of guitar modding, so that was quite fun.