After much deliberation, experimentation, determination, and the inevitable procrastination and distraction… I’ve finally completed this comparison of tone capacitor material types and capacitance values.  In part 1, I’ll evaluate a bunch of different dialectric material types to see how they change the character of the sound.  In part 2, I’ll cover how different capacitance values affect the range and usefulness of the tone pot.

The Tone Thing Back of the Tone Thing

First, I built this Tone Thing :)  It’s a piece of cardboard on which I mounted 7 different capacitor material types, and 7 Orange Drops of different capacitance values, and one Bourns 500k audio taper pot.  This is connected up with alligator clips to my Epiphone Riviera P93, in parallel with the signal at the output jack (the same place as the master tone in a regular guitar circuit).

.022uF caps of various dialetric material types

The caps in this corner are all .022uF of different dialetric material types.    Pictured left to right: Orange Drop 225P 100V (polypropylene), Mallory 150 series (metallized polyester film), Russian K-409 PIO (paper in oil), mystery vintage yellow cylinder (now identified- CDE polyester film/foil), the original Epi tone cap (probably mylar polyester film), mystery vintage gray cylinder (now identified- Mullard Mustard polyester film/foil), and a vintage tropical fish (polyester film).  Unfortunately, I couldn’t find a .022uF tropical fish – this one is a .033uF.  It will have a slightly different cutoff frequency, so it’s not quite all apples and apples, but I wanted to include it here anyway because it does have an interestingly different sound to it.

For each material type, I play at 4 knob positions: 10, 7, 5 and 1 (measured on the multimeter at 499k, 238k, 41k and 3k ohms).   For the examples, I wanted to keep each part short and simple – not too melodic or difficult, both to avoid distraction in comparing, but also to try with my limited playing skills to be as consistent as possible between each take.  By the end of this video, you will be very sick of the three little phrases I play 28 times each in the video! :)

Orange Drop capacitors from 1000pf to .047uF

Stay tuned for part 2, covering all the Orange Drops at different capacitance values, and the exciting conclusion :)

p.s. Thanks Jack for sending the PIO!

See part 2 for a description of RC filters, and how a guitar tone controls works, and how to choose a good capacitance value for tone.

See part 3 for a bunch of followup Q&A and some more audio examples.

See here for some blind tone comparisons.

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