Tiltsta

Originally Posted by Tiltsta

Capacitors can do a lot of different jobs; including storing large amount of electricity, moderating voltages (electrolytics), or filtering signals. The capacitors in guitars are filtering capacitors, or, more commonly 'filter caps'. All of these types of capacitors 'do' the same thing, basically separate two electrical conductor poles with a dielectric fluid or material that allows current to pass through with varying degrees of dampening. Of course, the type of cap and materials can be made such that electrons accumulate on one of the poles and store electricity (as in capacitors that turn on old TV tubes), or attenuate signals and smooth out signals from rectifiers and power amps (like in guitar amps), or filter out specific frequency ranges based on the type of dielectric in between the poles (like in guitar tone/filter caps). Filter caps, like those in guitars, are designed to filter out frequency ranges, and this is used to regulate the signal that goes to the guitar output jack. In guitars, the capacitors tend to be 'high pass' filters that shunt high frequency signals to the ground, while allowing lower sounds to make it to the jack. This makes for a more 'mellow' and 'less harsh' guitar sound reaching the output jack, as the really 'high frequency sounds' tend to bleed to ground. You can use any kind of capacitor to pick how much 'bright' you want to bleed off, but guitars tend to cluster around 0.22 and 0.47 microfarrads, with 0.22 being common with humbuckers where less high bleed is wanted, and 0.47 with single coils where lots of brightness needs removing. The bigger the microfarrad reading, the 'darker' your guitar tone will be. The voltage reading printed on the cap really doesn't matter in this application, as electric guitars make very little voltage. Most are rated at 50 -100 V, but some oil caps go upwards of 6-700v. Again, your guitar makes almost no voltage, so these voltage values are not worth worrying about. Of course, playing around with caps is a cheap way to alter a guitar sound, so a little experimentation is often worthwhile. Keep in mind this is a 'minor' impactor on 'tone', so don't expect a massive difference. I once bought a bunch of cheap caps and soldered alligator clips to my pot leads and plugged in different caps to test them all out. In general, those around the 'common' values listed above sounded best to me. I guess there is a reason these common values have been used again and again in the 60+ years of electric guitar...they work well. If you are doing something special, or different, changing cap values might be for you, but in general I hear "too bright, too muddy, or no different than the standard values". You may have better ears.

As for types of capacitors, they vary primarily in the type of dielectric material jammed between the poles. Almost all modern caps are ceramic, and these work well in guitars. Tone hunters dismiss them, but they are very accurate with low variance and are exceptionally reliable. People often describe them as harsh, perhaps grabbing the same lingo from ceramic pickups. There is nothing about these caps that should sound any harsher than any other type of cap. Note harsh is an 'audiophile' type term that is impossible to measure. Buy an audiophile stereo and look inside, ceramic caps. They focus more on speakers for their misinformation. These caps are exemplified by the 'green chiclet' types from radio shack or orange dot caps. Anyway, they work fine, but there are tons of different type of capacitors, so make sure you pick something appropriate for guitar. Some claim ceramic caps sound harsh, but I can't quite figure out why this is. I never noticed much difference in ceramic versus higher end materials. Film capacitors use a mylar coated film (or other plastic) to filter out frequency, and these are best exemplified by 'orange drop' type caps or black beauty caps. They have more variability than the ceramics, are bigger, and seem to be the industry standard for high end guitars. They sound good, don't cost very much, and if they are the cap of choice in a 3 grand guitar, they probably will work in your home brew build. These are cheap enough that I tend to use them when I wire stuff, and I go with sprague orange drops. Good quality, and do the job. These also are very stable and last virtually forever. The other common type of cap in guitars, especially those going for 'vintage' tone, is the oil in paper cap. These use paper soaked in oil as the dielectric, and are obsolete in everything but guitar player's minds. The big reason electronics have moved from these is the significant variation from individual units, and the difficulty in getting these to operate to design spec relative to the other more modern material models. Cost is another issue, as these tend to be reproductions made for 'ultimate guitar tone', so you pay for that honor, and get more variability. Again, some claim to hear differences between these and ceramics, and here it might make some sense, as these oil caps tend to be off spec quite a bit and this may impact tone a bit...but it isn't so controllable. These tend to wear out as the oil evaporates, but there are tons of 50's guitars floating around with these caps that still work, so who knows. Some people swear by these are a key ingredient for great tone, so it might be worth trying them out. I can't really hear the difference with these over cheaper modern caps. I guess let your ear be the judge, as even these caps tend to be fairly cheap.

Blah, blah, blah. That is a lot of typing. Sorry. Caps in guitars filter high frequencies and send them to ground (treble bleed). Swapping them can affect your guitar tone, but not in a massive way. They come in lots of types/construction, but there isn't much difference in them...as they cheapest models tend to be those with the tightest tolerances and most stable construction, where as the vintage style oil ones perform the worst (in terms of electronic specs). Some claim old oil type caps sound the best, but I never noticed much difference. Your mileage may vary.

This post is just to give some typical cap types you might see in a guitar....brands vary, as do colors, but you can get some info from just looking at the shape of the cap.

Ceramic caps are flat. Here is an orange disc capacitor. They are commonly green as well and rectangular and called 'chiclets' after the gum with a similar shape. There are also green film caps that are rectangular, so some people who slam ceramic caps and actually slamming the sound of film caps. Go into a radioshack and grab a capacitor off the wall, or open any modern electronic device, and these are the capacitors you will commonly see, at least for filter caps. Colors and size vary a lot by manufacturer and application. I guess the common thing is that they are small, and very thin/flat, and that makes them look different from the others.



Film capacitors look a little more elongated. The first picture is a classic bumblebee cap. The name bumblebee comes from the color stripes on the outside. The second is a modern spague orange drop film cap. These are the kind of cap in lots of high end guitars. I like the sprague orange drops in my guitar builds, as they sound good and lots of people use them. Kind of a compromise between tone hunting and cheapness. I figure if I am going to solder it, a couple of bucks on a cap I know PRS puts in their private stock guitars (or the fender custom shop, or any other number of builders) is good enough for me. The tend to be elongated, but I've seen square green film caps before, so shape isn't everything. They tend to be much fatter than ceramic 'disc' caps above.




Mica caps. Silver mica caps have a lump in the middle. They are not very common in guitar circuits. They are common in amp circuits and other electronics, but I have no idea why they are preferred in some applications and not others. I should ask my brother the electrical engineer about that one some time.



Oil in paper caps look like a small battery......