Cable capacitance

[wolf5150]

Does anyone know how to measure cable capacitance ?

I'm just curious what method is used.

:friday:

 

[trevorus]

Cable disconnected from everything, and use a multimeter, one on the top of the connector, one on the ring.

Sent from my SCH-I535 using Tapatalk 2

 

[ItsaBass]

Re: Cable capacitance

Cable disconnected from everything, and use a multimeter, one on the top of the connector, one on the ring.

Sent from my SCH-I535 using Tapatalk 2

You'd need an LCR meter, not just a run-of-the-mill multimeter, wouldn't you?

 

[glassman]

Re: Cable capacitance

You'd need an LCR meter, not just a run-of-the-mill multimeter, wouldn't you?

Any multi-meter with capacitance capability will work.

The value will be insignificant though; there is capacitive coupling all through an amp circuit and the cable is only one of the contributors.

 

[ItsaBass]

Re: Cable capacitance

Any multi-meter with capacitance capability will work.

That's kind of what I meant. Saying LCR was a bit too specific to make my point correctly.

I wasn't aware that run-of-the-mill multi meters measured capacitance.

 

[trevorus]

Re: Cable capacitance

That's kind of what I meant. Saying LCR was a bit too specific to make my point correctly.

I wasn't aware that run-of-the-mill multi meters measured capacitance.

Yeah, I have some regular meters that test capcitance. They don't do well with large values, but they work for most stuff in an amp circuit.

 

[Blix]

Re: Cable capacitance

You have to measure the cable alone, the connector adds capacitance as well.

 

[uOpt]

Re: Cable capacitance

Multimeters can measure capacitance in different ways.

The cheap ones with capacitance capability (heh) will only measure capacitance reliably if there is no inductance. This might throw off your measurement a bit, but you'll probably be OK.

The plug doesn't add significant capacitance.

 

[wolf5150]

Re: Cable capacitance

Thank you

 

[hermetico]

Re: Cable capacitance

Capacitance increases with length also!

 

[trevorus]

Re: Cable capacitance

Capacitance increases with length also!

That's what she said.

 

[hermetico]

Re: Cable capacitance

That's what she said.

She who?

 

[zzmoore]

Re: Cable capacitance

You have to measure the cable alone, the connector adds capacitance as well.

Would he be using the cable without the connectors.?

 

[Blix]

Re: Cable capacitance

Would he be using the cable without the connectors.?

For the ultimate tone, yeah!

My point is: there's actually huge differences in capacitance between various brands of connectors. Measuring two different cables with different plugs could give you misleading results.

Check out this thread: http://www.hugeracksinc.com/forum/viewtopic.php?f=1&t=84227&hilit=capacitance

Now this isn't really that important in the big picture of course...

 

[uOpt]

Re: Cable capacitance

For the ultimate tone, yeah!

My point is: there's actually huge differences in capacitance between various brands of connectors. Measuring two different cables with different plugs could give you misleading results.

Check out this thread: http://www.hugeracksinc.com/forum/viewtopic.php?f=1&t=84227&hilit=capacitance

Now this isn't really that important in the big picture of course...

That's the most ridiculous article I have seen. Sure, the different plugs have different capacitance. But all of them are negligible compared to the capacitance of the actual cable.

Here are some cable values:

My Vox guitar cable:                   0.41 nF
Short cable + crocos:                  0.06 nF
My test harness 20080123:              0.3 nF
Cheap 6 ft guitar cable, stereo:       0.7 nF
~95 feet of Belden 8262 one hot:       5 nF
~95 feet of Belden 8262 both hot:      9 nF

So, no, whether your plug has 5 or 10 pF won't matter.

 

[Blix]

Re: Cable capacitance

That's the most ridiculous article I have seen. Sure, the different plugs have different capacitance. But all of them are negligible compared to the capacitance of the actual cable.

Here are some cable values:

My Vox guitar cable:                   0.41 nF [COLOR="Red"]=410 pF[/COLOR]
Short cable + crocos:                  0.06 nF = [COLOR="Red"]60pF[/COLOR]
My test harness 20080123:              0.3 nF [COLOR="Red"]= 300 pF[/COLOR]
Cheap 6 ft guitar cable, stereo:       0.7 nF [COLOR="Red"]= 700 pF[/COLOR]
~95 feet of Belden 8262 one hot:       5 nF = [COLOR="Red"]5000pF[/COLOR]
~95 feet of Belden 8262 both hot:      9 nF = [COLOR="Red"]9000pF[/COLOR]

So, no, whether your plug has 5 or 10 pF won't matter.

Say you have a pedalboard with 5 pedals, all true bypass, then 10 neutrik plugs at 33pF each adds the same capacitance as 8-10 feet of regular 30 pF guitar cable. Add more pedals and plugs and the loss of high end will quickly be quite noticeable. So it's not really ridiculous...
But all negligible if you have a buffer in front of course.

But as I said, in the big picture it is this isn't any issue for most.

 

[uOpt]

Re: Cable capacitance

Say you have a pedalboard with 5 pedals, all true bypass, then 10 neutrik plugs at 33pF each adds the same capacitance as 8-10 feet of regular 30 pF guitar cable. Add more pedals and plugs and the loss of high end will quickly be quite noticeable. So it's not really ridiculous...
But all negligible if you have a buffer in front of course.

But as I said, in the big picture it is this isn't any issue for most.

Fair enough, but the first pedal that changes impedance (has no true bypass or doesn't current use it) makes the signal immune to all the capacitance values. Plus hopefully a lot of people have some form of routing for pedal groups and don't always drive the whole signal chain through 10 pedals. And if they do I think there's no chance that it sounds good without some form of impedance change.

 

[Blix]

Re: Cable capacitance

Fair enough, but the first pedal that changes impedance (has no true bypass or doesn't current use it) makes the signal immune to all the capacitance values. Plus hopefully a lot of people have some form of routing for pedal groups and don't always drive the whole signal chain through 10 pedals. And if they do I think there's no chance that it sounds good without some form of impedance change.

Indeed, it's only really an issue if all pedals are off and true bypass.

But too many buffer isn't always a good thing, I wonder how this sounds:

 

[uOpt]

Re: Cable capacitance

Indeed, it's only really an issue if all pedals are off and true bypass.

What I am saying is that replacing all your plugs in the cables between 10 or 20 pedals might not help that much.

Even with true bypass the pedal itself, namely it's own connectors and the switch, will have substantial capacitance, if you rate 5 nF as substantial.