Cable Capacitance, opinions, facts?

[Keven]

Hello!

in a quest to further educate my co-workers and my boss (after an afternoon slight discussion on why i made certain guitar and mic cables 18' instead of 20') i'd like to discuss the effect of cable capacitance with you guys here.

to be honest, i have no opinion on it. i know that electrically it's a fact that two insulated conductors never connecting to one another and do store some sort of AC charge. and that it seems to effect higher frequencies (BKP pickups seem to discuss this concept at the scatterwinding part of the explaination of the building process..) but in an attempt to make better decisions at custom cable making (and better purchase orders for bulk cable....) how important it is?

said cable was from a mic to the preamp. now that it think about it, it doesn't really matter for microphone cable since AFAIK microphones are low impedance devices, so cable capacitance doesn't affect treble frequency so much.

as far as guitar cable, it does matter from the guitar to the amp, or first pedal, as that's where you can have a bit of treble loss (again, personally, i like that loss on single coil guitars, on humbucker guitars i don't...)

trying to find a bit of facts to back up my claims online i haven't really found any decent source material. as i'm the eternal scientist instead of ''hokey religions and ancient weapons'' type of guy, if anyone has additional info about this effect, i'd appreciate.

this sums up what i know.

Capacitance effect doesn't matter if:

the source is DC (which pretty much excludes any audio signal)
the source is low impedance
The cable length is (IE: wiring inside a guitar/pedal)

Capacitance effect matters if:
the source is AC
the source is high impedance
long cable runs

What else is there to talk about? discuss!

[jpfamps]

You're on the right lines.

The cable capacitance does have a significant effect on your tone for two reasons.

Firstly high frequencies are shunted to ground by the capable capacitance.

Secondly the guitar pickup's output impedance forms a resonant circuit with the cable capacitance, and this can actually cause peaking at certain frequencies. See the link below for details:

http://terrydownsmusic.com/technotes/guitarcables/guitarcables.htm

They actually make a slight error in the equivalent circuit for an amplifier, in that most amps have a grid stopper resistor (typically 33-68k) that isolates the amp's input capacitance (the 100pF cap on the end) from the guitar. Regardless, the conclusions will be the same.

If you use all true bypass pedals (assuming you use pedals....) then all the cable between your guitar and amp will contribute to the cable capacitance. If you use a buffered pedal, such as any Boss pedal, then the only the cable to the first buffered pedal will contribute (also the input capacitance of the pedal is likely to be much lower than the 100pF of an amplifier without a grid stopper).

An active buffer in your guitar (assuming it's been designed properly) will negate cable capacitance effects for any sensible length of cable.

Hopefully this helps.

The bottom line is, cable capacitance does vary between cables, and can affect your tone, although obviously it's down to the end user to decide whether this is good, bad or indifferent. Low capacitance isn't always better.

For what it's worth I use about a 20 ft Van Damme cable with Neutrik jacks straight into the amp as I find these very durable.

[HTH AMPS]

For what it's worth I use about a 20 ft Van Damme cable with Neutrik jacks straight into the amp as I find these very durable.

^ +1

I've been using the same blue Van Damme cable with Neutrik jacks for over 10 years.