How to make a Humbucking Pickup for a

Guitar

(the hard way!)

(Part II)

By John Fisher

 

The Base Plate

The back plate is used to support the pickup and mount it to the plastic ring which also has the adjusting screws and springs that are used to adjust the height of the pickup. It is also used to shield the inside of the pickups from noise.

 

Here is a diagram with some detailed dimensions of the base plate The base plate needs to be made from some metal that is not sensitive to magnets like brass. I got some stuff downtown that was part brass and part tin (I think) that was really cheap. You can use aluminum but then you won't be able to solder to it. It is normal to have 4 small screw holes in the base plate for small screws that will screw into the bobbin. I didn't do that because I just held everything together with the wax. If you were to make a pickup not using a metal cover on the front then the screws would be necessary.

 

Here you can see that I drew out the pattern on the brass plate. Normally it is best to use a finer pen or scribe the shape but I just wanted to be able to illustrate the idea better.

 

Here it is cut out. I was able to use just ordinary tin snips for the job then I filed the edges.

 

Here it is bent to shape. I just used a pair of pliers to do this. You will notice that I made some small holes for where the pickup adjusting screws will go. The ideal is to tap the hole with the correct thread but I just made it so that the screw fits tight in the hole. Another option is to solder a nut to the plate.

 

This is the side of the plate that will go into the pickup.

 

Here is the base plate inserted into the pickup. It is not shown but the plate is then soldered at several points to the pickup cover. This needs to be done with a fairly strong soldering iron. (At least 60 watts).

 

Magnet Orientation

The question will arise: " which way does the magnet go?". After asking many of these questions myself, Jeff and others over at Ampage, helped me a lot with these questions. Generally speaking the south pole of the Magnet should face the adjustable poles.

I got lots of anwers to my questions over at Ampage. Got to firebottle .com and then to Ampage and there will be a form on making pickups. They also have some hard to find materials that they offer for sale for making pickups

 

Here is how the magnets are oriented on the guitar. If you were to get 2 identical pickups for a guitar you simply turn one around in relation to each other. The only real difference in the neck pickup and the bridge pickups is that the bridge pickup ( in this case) has 5000 turns per coil and the neck pickup has 4500 per coil and the pole pieces are slightly closer together on the neck pickup.

 

How to tell which is the North Pole and which is the South Pole of a Magnet

 

Jeff told me that you can know which is the north pole and which is the south pole of a magnet by simply getting a compass at Wall Mart for about 4 dollars. Well mine cost me about $1.80. You will notice that the north and south poles of a bar magnet for a pickup don't go from end to end but from side to side.

Wiring the Pickup

There are many ways to wire up pickups which will create a wide variety of results. This is a subject all in itself but for the pickups I made here I wired them in the most common manner which is the 2 coils of each pickup in series. I will save all the hot rod wiring for my next guitar which will be a solid body rock and roll guitar.( I think)

 

Here is the most common wiring for a humbucking pickup. The series wiring makes the pickup powerful. The wire that is ground will also be connected to the case or pickup cover which is shielded. Note that you can use either of the 2 outer wires as either hot or ground. The only difference is that it will change the phase of the pickup depending on what wire is used for ground or hot. If you are using 2 pickups on a guitar you usually want them both to be in phase with each other. If they are not in phase with each other, you will get an unusually thin snarling sound without much bass when the 2 pickups are on together. If this happens the 2 pickups are out of phase and you need to simply reverse the 2 outer wires of one of the pickups to correct the problem. Some people will even install a switch to have this option of out of phase pickups as an effect.

 

Some Different Pickup Wiring Configurations

 

Example "A" is probably the most common way to wire up a humbucking pickup. It's wired in series so that the 2 coils with 5000 turns each (in my case) add up to 10,000 turns each which I got a DC resistance of about 8K. This gives a fairly powerful pickup.

Example "B" is wired in parallel which gives a clearer tone and is a little brighter but with a weaker signal. (Not as good for rock and roll). Please note that if the 2 coils are in parallel and each coil has a DC resistance of 4 K then the DC resistance of the pickup in series will be only 2K. This is why the signal will be weaker and the weaker signal is the trade off of having a clearer tone.

 

 

Example "C" is where you make a tap between the 2 coils and when connected like that you have a single coil pickup. Not a totally authentic strat sound but it gets a lot closer to it. It is no longer humbucking.

Example "D" has 5 wires that come out of the pickup.(4 connections for the 2 coils and a 5th one which is connected to the base plate or pickup cover as ground. Having the 5 wires coming out of the pickup gives you the option of any configuration desired. In any of these examples illustrated you may want to have switches to change the different configurations to give a large variety of sounds. It is even possible to have a multi switch setup on each pickup giving you even more sounds using the 2 pickups. You can even have a switch to make the 2 pickups in series with each other and so forth, so there is lots that you can do. Instead of drilling a bunch of holes in your guitar there are pull out switches available that mount where the normal knobs of the guitar go only that the knobs can be pulled in and out for different switch settings. It all depends on what you want out of your guitar and what your preferences are. I once had my guitar wired like this with dozens of options but after using my guitar for a couple of years there was only a few settings that I ever really used and many that I never used but the extra options were still nice to have for that one song that needed it.

 

The Finished Result

I was very pleased with the sound of these pickups. The balance between the neck and bridge pickup was just about right. Of coarse these pickups will sound a little different in a solid body guitar as this electric arch top that I built has a sound of it's own and the body really plays a big part in the sound.

Click here for a little sample of how it sounds

I recorded it on my homemade Fender Super Reverb style clone at low volume. It's nothing fancy but it is just to let you know how it sounds clean. I have the switch with both pickups on at the same time.

 

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