The connection from an electric guitar to the amplifier carries a very low level signal, which means that the connection has to be pretty good to avoid getting crackles and loss of signal on scratchy connectors. The guitar lead is often moved, which can lead to fraying cables and broken connections. Finally, musicians often just plain abuse their gear.
The Guitar Plug - a 1/4 Inch Audio Jack Plug
Almost all guitar plugs are 1/4 inch jack plugs. This venerable connector has been around for donkey's years, and is well suited to the application. It is a big connector, which makes it reasonably robust - the metal sleeved variety can usually survive being stood on, and the large size means that the contact area is quite big, which is good for getting a decent electrical connection.
How to Wire A Guitar Cable with Two Jack Plugs
Most guitar cables are wired with mono jack plugs. Depending on where the socket is on the guitar body, it may be worth considering a right-angled plug at the guitar end. Because of the rough treatment these cables get use only metal bodied connectors - somebody is going to step on it or put a speaker cab on it.
Select the cable. There are several things to look for here
- Coaxial cable - anything else will pick up hum and interference
- decent shielding - though it is a right pain to work with braided cable offers great shielding.
- low capacitance, on the order of less that 150pF/metre
- stranded centre conductor - solid core centre conductor will fracture under typical guitar usage.
- robust enough outer jacket to cope with the rigours of use on stage
A typical cable length is about 3m (10 feet). If the cable is made too long then the capacitance of the cable may interact with the high impedance of the guitar pickup to rob the sound of high frequencies - for longer cables it is important to select low capacitance cable.
How to Fit a Guitar Plug To the Guitar Cable
This has to be done twice, one at each end of the cable. First things first - unscrew the shell of the plug, and slip this over the cable, and then the insulating sleeve that is provided with metal-bodied plugs. Fail to do this and the connector has to be unsoldered and remade. It is possible to slip the shell onto the cable from the opposite end if this is forgotten the first time, but when it comes to the final plug this has to be got right.
The next stage is to measure out the length of the cable outer jacket that has to be stripped back (see photo). It is best to measure this against the plug. The jacket can be stripped back either by carefully scoring around it using a sharp knife, being careful not to cut so deep as to nick the screen conductors, or by using a proprietary cable stripping tool.
Once the jacket has been stripped back, if the screen is braided unpick the braid - the awl of a Swiss Army Knife is a really good tool for this. The braid then needs to be pulled back, and the very ends of the strands gathered, twisted and soldered to keep them together. The claw of the plug should be splayed out so that the cable can go into it - the aim is that the outer jacket ends just after the claw, so that it is gripped by the claw rather than the conductors of the shield.
How to Solder the Guitar Plug to the Guitar Cable
The inner can then be measured to the inner tab, cut to match and about 2mm of the insulation stripped from the inner. This tends to shrink back a little when heated. With the jack connector held in a bench vice, the strands of the inner conductor can be passed through the hole in the tab, and formed into place with needle-nosed pliers. The tab can then be heated and solder applied, soldering the inner conductor to the tab.
The shield can then be made - the trick is to rotate the connector to the shield lug of the plug is uppermost, and the strands of the outer shield can then be brought over the lug and soldered (see picture). The claw needs to be reformed with pliers to grip the cable outer jacket. It only remains to inspect the connection, bring up the insulating sleeve and screw the connector barrel to the plug. Repeat at the other end and the guitar cable is now complete.
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Readers may be interested in How to Solder Electronic Components , How to Wire a Jack Plug which covers stereo jack plugs occasionally used on guitars, and Acoustic Treatment Principles for Home Studios.
Richard Mudhar - Originally from London, now enjoying a less hectic pace of life in Suffolk, Richard Mudhar is a keen wildlife sound recordist and ...
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