I need/want to exchange parts of the electronics. What parts should I get?
An electric guitar or bass contain many electrical components. Perhaps you desire to change out parts for a different functionality or maybe something has stopped working? For whatever reason, certain components will surely need to be exchanged at one time or another and there are a few things that will be good to know in such situations.
A guitar potentiometer is a variable resistor, nothing more and nothing less. There is no such thing as a volume, tone, humbucker or single coil exclusive pot for either active or passive pickups. Beside the build quality itself, the difference between pots lies within their applied total resistance and taper, which makes certain pots the traditional choice in typical situations. There technical properties in conjunction with the way the pots are wired make them react a certain way in an electrical circuit.
What's the correct pot value for my guitar/pickups? There is no right or wrong choice when it comes to pot values. If the resistance of the pot is higher, less treble frequencies will leak to ground and the tone of the guitar/pickup will be brighter and the other way around. This is the reason that 250K pots are the traditional choice for single coil pickups (to make them less harsh) and 500K pots are the traditional choice for humbuckers (to make them clearer and less dull). The correct choice is the resistance value that sounds good to your ears. If you want more highs, choose a higher value. If you want a warmer tone, choose a lower value.
Most active pickups use 25K pots, which is drastically different from what is commonly used for passive pickups. Active pickups are usually ok with any resistance between 25K and 100K without behaving erratically. The reason for the special treatment of active pickups has do with output impedance, which is usually a lot lower in active pickups compared to their passive counterparts. This makes them require lower resistance pots. If 250K/500K pots are used with active pickups, the controls usually acts more like switches than pots and if 25K pots are used with passive pickups, the sound will be exceedingly dull.
What is pot taper? The taper of a pot is the manner in which the pot applies resistance in all positions between zero and max. At zero or max setting, the taper does not affect tone. There are two dominant types of tapers for pots used in guitars, and these are Logarithmic or Audio taper (A) and Linear (B) pots. Logarithmic pots apply resistance exponentially throughout their rotation in a way that is commonly perceived as "even" to the human ear. This makes "A" pots the most popular choice for both volume and tone controls in electric guitars and basses. All .strandberg* guitar are fitted with this kind of pot in all positions. "B" pots apply resistance evenly throughout their rotation and are commonly perceived as "nothing happens until I'm almost at zero". Ok, so uneven (A) is even and even (B) is uneven? Correct! The confusion is understandable. The reason for this contradiction is the way the human ear compresses sound and compressions properties in the signal chain. Exponentially applied resistance from the pots is commonly needed to achieve a subjectively even curve and act as compensation for compression in the signal chain and the human hearing.
There are a lot of other kinds of pots as well and you should always choose the pots that you like the best. Whenever a pot breaks down on your .strandberg*, simply exchange it for your favourite. It does not need to be identical to the original pot.
Why do pots crackle and act out? The conductive material used in pots is usually Carbon. In contact with Oxygen in the air, Carbon will oxidize and the oxide will cause crackling and drop-outs. Oxide is either removed by heavy use of the pot (mechanical removal) or by spraying some oxide solving electronics spray inside it (chemical removal). If the pot has not been used for a long time, problems with oxide are to be expected. Turn the pot over and over again many times, perhaps in combination with some spray to get rid of it. If nothing helps, it's time to exchange the pot.
Switches are different in shape, size, number of poles and number of positions. We use CRL switches, but all .strandberg* guitars will accomodate any switch of equal size/form factor. Switches does not commonly affect tone and you can therefore use any switch for any guitar/pickup, passive or active. If a guitar is delivered with a 3-way switch, this can usually be changed for a 5-way and the other way around. If the switch is broken, simply exchange is with one of equal size and functionality. If you're contemplating modification, choose any switch of the correct size, but another number of poles and switching positions. Don't forget that most switches can be wired in different ways. Perhaps you don't have to change it at all?
Why do switches crackle and act out? The contact points on switches may be made from different metals. Most metals with good conductive properties except Gold, oxidizes in contact with Oxygen in the air which leads to crackling and drop-outs. Switches could therefore be Gold plated and these kinds of problems would not exist. The price of guitars parts would then again be drastically different if they were. Crackling is removed in same way as with pots or by exchanging the switch. All problems with switches are however not related to oxide. All mechanical parts can bend from wear or shift with temperature, which means that drop-outs you're experiencing could be caused by surfaces simply not touching each other. In such cases, the metal tongues may be bent back to contact with your fingers or a small set of pliers.
Output jacks come in a number of shapes and forms. We use Pure Tone stereo jacks on all of our guitars because of their secure connections and favourable size in crowded spaces. Any other jack with the same number of contact points may be used in a .strandberg* guitar as long as it's possible to fit inside the electronics cavity. Normally, passive instruments require a jack with two connectors (mono), which corresponds to output + ground. Active instruments in return require a jack with three connectors (stereo), which corresponds to output + ground + negative side of battery. A mono jack could be used on an active instrument, but the battery would then be engaged all the time with shortened battery life as result. A stereo jack can be used on a passive instrument without any side effects. The third connector will simply act as a second ground and does not affect tone or functionality. The stereo jack in an active instrument act as on on/off switch for the battery. Please remember to disconnect the cable when the instrument is not in use to prolong battery life!
Why do jacks crackle and act out? Just like switches, the metal in output jacks may oxidize or get bent out of shape. If bent, metal connectors can be bent back to restore proper contact and oxide can be removed by the use of oxide solving electronics spray. If everything else fails, exchange the jack.
Beside pots, jacks and switches, there are also other components found inside most guitars and basses. Notably, you will find a capacitor that makes the tone control a tone control. There are many opinions about the tonal properties of tone controls caps, but most importantly, the value of the cap sets the cutoff frequency of the tone control. What does this mean? This means that the higher the value of the cap, the more frequencies will be cut out as you turn the tone control down. At zero position, a very high cap value will make the tone control cut out everything except bass frequencies. A very low cap value will in return only cut out the highest highs and leave most of the midrange and lower treble unchanged. What you prefer is up to you, but most players tend to like a cap value somewhere in between the extremes. At .strandberg*, we use 0,022uF and 0,047uF caps for our tone controls. There are many different kinds of caps on the market. Whether these all sound different or not we will leave upp to your own opinion. Choose whatever cap that sounds best to you. Our guitars will work well with any choice of tone control cap.
You may also notice that there is a capacitor and a resistor wired in series on all .strandberg* volume pots. This kind of circuit is called "treble bleed" and is designed to keep the tone of the guitar bright and clear as the volume control is turned down. Much in the same way as with a guitar tone control, the component values chosen will affect the cutoff frequency of the treble bleed. A higher cap value will preserve more treble frequencies and at a certain point, the tone of the guitar will actually turn brighter instead of darker as the volume is turned down. We have chosen to use a 680pF cap together with a 150K resistor as this, in our opinion, gives the guitar a balanced timbre in all positions of the volume control. As always, please use any component values that suits your needs. Your .strandberg* will work with all of them.