Cables 101 #2 - Capacitance: The Biggest Tone-Changing Factor
What is Cable Capacitance?
Probably the single most important factor that alters your tone in cables, there are several schools of thought concerning cable capacitance. Before we get into what we think, let’s briefly touch on what capacitance is and how it affects your signal.
Most instrument cables contain two conductors within them. In very basic terms, these two conductors and the insulation between them form a capacitor, which holds an electrical charge.
This electrical charge is measured in picoFarads (pF) per unit length. Here in Singapore, we use the metric system, so we give measurements in pF per metre (pF/m).
How Does This Affect My Tone?
Well, let’s put it this way. When your cable has no capacitance at all (0pF/m), the entire signal from your instrument passes through unblemished. Unfortunately, with current copper cable technology, all cables have some capacitance in them. That capacitance makes your tone sound like you’ve rolled the tone knob down a little on an electric guitar. The more capacitance the cable has, the more you roll off the very high frequency harmonic content in your signal.
The length of your cable affects the amount of capacitance a cable has, and in turn affects your tone as well. A 6m cable will have twice the capacitance compared to a 3m one, and will sound muddier as a result.
In a nutshell, more capacitance = less sparkly, airy treble in your tone.
Some of you might say, “Oh, I don’t like my tone to be all trebly anyway!”
But sincerely, we think that’s just not the job of your cable.
What Should a Cable Do?
We believe that a cable’s job is to carry your instrument’s signal as purely as possible, because your (usually expensively assembled!) tone shaping gear does tone shaping much more musically, and much more flexibly than a cable can. We certainly hope so anyway!
Also, don’t forget about your tone knob, which does just about the same thing.
Which Instruments are Most Affected by Capacitance?
Which type of instrument does capacitance affect the most? Passive instruments. Most electric guitars and basses are passive, meaning that their pickups are not battery-powered. Passive pickups have a weak signal, so pedals or amps usually have high input impedances (similar to resistance) to make sure your tone sounds full.
Cable capacitance doesn’t matter as much if the pedals or amps you’re plugging into have low input impedance, but that results in tone suck (thin and weak tone). Hence, the better choice is to have high input impedance coupled with low capacitance cables.
If you want to know a little bit more about impedance and how it affects your tone, check out this article right here – Mr. Black explains it all very clearly indeed.
Strutting along the path to further cable knowledge? Here's our current list of articles:
- Cables 101 #1 - Introduction: The Best Instrument Cable In The Universe???
- Cables 101 #2 - Capacitance: The Biggest Tone-Changing Factor
- Cables 101 #3 - Core Material: Conductivity
- Cables 101 #4 - Techflex: Braided Plastic Protective Shield
Check back often - we'll be adding more in time to come!