OK, so let’s continue with the list of tone caps you should try in your Strat.
Silver mica caps are made from a dielectric of mica with a silver dip coating, hence the name. Modern silver mica caps are easy to identify because they have a typical hump in the middle of the body. NOS silver mica caps usually have a flat, rectangular shape. They can be found inside high-quality amps and stompboxes. They can also be used as an excellent high-cut cap on a guitar’s volume pot. If you can find the correct value, they’re also excellent as a cap for the tone control. Higher values are often hard to find, big in size, and very expensive—but worth a try. They really sound excellent, without any coloration. They’ll improve a guitar’s tone dramatically, and they’ll improve top end and clarity due to their low-loss design—they’re the absolute best-sounding caps for tone circuits, tone stacks, and filters. A good substitute for silver mica caps are the Styroflex caps I mentioned last month. They’re much smaller in size, and therefore much easier to handle as a tone cap.
Paper-in-Oil (aka “PIO”)
These caps from Jensen, Sprague (Vitamin Q), Mundorf, and some others can usually be found in high-end hi-fi equipment like audio power supplies, decoupling stages, and speaker crossover filters, as well as high-quality guitar amps. They are very expensive, but many swear by them. Naturally, you can use them inside a guitar if you have enough space for such a tone cap. These capacitors use oil-soaked paper as dielectric material and are therefore well damped and very transparent, smooth, defined, punchy, and natural sounding— bandwidth is very high and distortion very low. The very early Sprague Bumblebee caps from the ’50s are PIOs, and they’re easy to identify because of the blob at one of the leads. Plenty of NOS PIO caps are available, and they’re excellent quality—some are even military graded—and they’re often cheaper than caps from Jensen and others.
Mullard/Philips C280 “Tropical Fish”
Mullard/Philips C280 “Tropical Fish” capacitors
Paper-Waxed (aka “PIW”)
An example of a paper-waxed (aka “PIW”) capacitor
NOS “High Voltage” Ceramic
A NOS “high voltage” ceramic capacitor
All right, that’s it. Many more tone caps are available, but it wasn’t my intention to make an exhaustive list. I wanted to focus on the caps that work well in a Strat. NOS Bumblebee caps, for example, don’t sound very good in Fender guitars, so we’ll talk about these caps when we switch over to the Les Paul and 335 mods. Next month, we’ll close this chapter by discussing the orientation of caps. I’m sure there will be some surprises in store. Until then... keep on modding!
Dirk Wacker lives in Germany and has been addicted to all kinds of guitars since age five. He is fascinated by anything to do with old Fender guitars and amps. In his spare time he plays country, rockabilly, surf and Nashville styles in two bands, works part-time as a studio musician for a local studio and writes for several guitar mags. He is also a confessing hardcore DIY guy for guitars, amps and stompboxes and runs an extensive webpage,singlecoil.com, about these things.