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18 vs 20 ft cables?

S

steelhead2

Jun 18, 2009
554
6
Rogue River Oregon
#1
ok tried the search function for this question,old guitar slinger(western swing hall of fame member)told me yesterday something to the effect;`don't buy cables longer than 18 ft'

and i have seen 18's listed FSale (and my) question of;why not just make em an even 20?,so of course that was my response,and he said`took em awhile to figure that out':confused:

chit chatting on a walk by so no time to ask for substantion:hmm:and hey the man's a pro albeit semi-retired so without further waste of bandwidth=IS there a dif.???

yeah i know Albert Collins used a 100ft'r;) but why would the man tell me that?is there somthing with a guitar versus a bass?
 
#2
He was being a dolt. The longer the cable, the more it affects the tone of a passive bass --but not an active one. So with a passive bass (or guitar) a 1' cable is better than a 6', is better than a 10', is better than an 18', is better than a 25', etc.
 
#3
There is NO DISCERNIBLE DIFFERENCE!!

Maybe when he was playing there were only 18 and 30 foot cables available, etc. and that figure stuck in his mind.

ALSO -if you have an active instrument cable length doesn't matter. The Preamp can drive long cables no problem.
 
#5
As you increase the length of a cable, the parasitic capacitance also increases. If you have a high impedance signal from a passive bass, this capacitance will give you "tone suck," however, if you lower the output impedance of your signal with a buffer or preamp, the capacitance of the cable will have much less of an effect on your tone.

Keep your cables short if you've got a high impedance signal.
 
#7
My understanding was that basic rule of thumb was you can get some signal loss after 20-25 ft. With heavier gauge well sielded showing less loss. However haveing lowz signal from either active pups or preamp pretty much negates that. So that longer runs of 30 plus ft are ok with no signal loss.
 
#8
Just so's you know, more shielding doesn't create lower capacitance, and higher gauge could actually result in more capacitance (there's more capacitive material between point A and point B).

But otherwise, yeah I think a decent rule of thumb is that somewhere between 15 and 25 feet (depending on capacitance per foot of the specific cable) is the range where the tone loss can go from "imperceptible" to "perceptible".
 
#11
18' is more environmentally friendly than a 20' cable. That seems to be the spin on being cheap and charging the same for less material. I call shenanigans, but it is 2' more green. Or 2' shorter depending on your POV.
 
#12
line6man said:
"Capacitive material?"
You mean a greater plate area?
Click to expand...

The cross-sectional area of the cable is greater. Now, I may be wrong that more area of copper means more storage capacity, and if so I'll own up to that mistake. Am I wrong?

FWIW, my tests so far indicate a greater tendency to high capacitance among super-thick cables.
 
#13
this man is a lead man not a bass player,i barrowed a couple cables from him last night,having odd issues with my combo:hmm:

my thoughts after i made the post today=(being a car/motorcycle/autobody guy) longer would mean more resistance like running a weed whip or electric drill,out at 200 feet from the plug in,of course cable material,thickness,MUST all be able to contribute to variences,not being a scientist i'm sure there many variables like weather temp(ambient),voltage drop thru connections etc. etc.

i'm going to follow up on this,i believe it has to do with recording,this guy started in `67 in the san fran bay area,worked nev casinos for decades,he may be archaic for sure but he's still doing studio work as well as live gigs,i'll come back on this when i give his cables back(and yeah,you can bet technology has changed,just since he`retired' 12 years ago;)
 
#14
bongomania said:
The cross-sectional area of the cable is greater. Now, I may be wrong that more area of copper means more storage capacity, and if so I'll own up to that mistake. Am I wrong?

FWIW, my tests so far indicate a greater tendency to high capacitance among super-thick cables.
Click to expand...

My initial thought would be that the insulating layer would get thicker in proportion. If so, both the dielectric thickness and the area of of outer conductor go up with cable gauge which would cancel each other out (C=keA/t). If you're seeing higher capacitance in thicker cables that would mean that the insulating layer isn't growing in proportion to the overall cable diameter. Which could quite possibly be true.
 
#15
UncleFluffy said:
My initial thought would be that the insulating layer would get thicker in proportion. If so, both the dielectric thickness and the area of of outer conductor go up with cable gauge which would cancel each other out (C=keA/t). If you're seeing higher capacitance in thicker cables that would mean that the insulating layer isn't growing in proportion to the overall cable diameter. Which could quite possibly be true.
Click to expand...

The way I see it, increasing the circumference of the signal-carrying conductor increases the plate area, which increases the parasitic capacitance. Additionally, to keep the outer diameter of the cable the same, the insulation would have to be made thinner, which would decrease the plate separation, further increasing the capacitance.

It wouldn't make sense for a thicker cable to have a higher capacitance, unless the dielectric was kept thin, while the plates (Signal-carrying conductor and shield) were given an increased area.
 
#16
line6man said:
The way I see it, increasing the circumference of the signal-carrying conductor increases the plate area, which increases the parasitic capacitance. Additionally, to keep the outer diameter of the cable the same, the insulation would have to be made thinner, which would decrease the plate separation, further increasing the capacitance.

It wouldn't make sense for a thicker cable to have a higher capacitance, unless the dielectric was kept thin, while the plates (Signal-carrying conductor and shield) were given an increased area.
Click to expand...

Yep. I think we're agreeing from slightly different angles.

If everything grows in proportion, the capacitance should stay the same. The only way the capacitance can go up is if the conducting bits grow faster than the insulating bits between them. (Or the insulating material changes, of course).
 
#17
steelhead2 said:
old guitar slinger(western swing hall of fame member)told me yesterday something to the effect;`don't buy cables longer than 18 ft'
Click to expand...

Why such an arbitrary number?

Three things to keep in mind are that number one, the parasitic capacitance of every cable is different, so you could have an 18 foot cable with even less capacitance than a 20 foot cable, depending on it's construction, number two, the effects of cable capacitance are based upon the signal's impedance, so not every bass is going to show the same amount of treble loss with whatever length of cable, and number three, one man's tone suck is another man's desirable effect.
 
#18
I haven't dissected any of the super-thick (super expensive!) cables I've tested, to confirm the wire thickness vs. the insulation thickness. Most of them have sealed ends, too, so it's not as easy as just unscrewing the plug body to take a look. This is something I definitely want to include in my data, but I haven't figured out a good way that doesn't involve cutting the cable in two.

I can say though that of the thickest cables (meaning by total outside diameter), only one (the Elixir) has lower-than-average capacitance. The others all have higher-than-average capacitance, seemingly in correlation to their outside diameter. I know that is probably not a real correlation, it just looks like one.
 
#19
bongomania said:
I haven't dissected any of the super-thick (super expensive!) cables I've tested, to confirm the wire thickness vs. the insulation thickness. Most of them have sealed ends, too, so it's not as easy as just unscrewing the plug body to take a look. This is something I definitely want to include in my data, but I haven't figured out a good way that doesn't involve cutting the cable in two.

I can say though that of the thickest cables (meaning by total outside diameter), only one (the Elixir) has lower-than-average capacitance. The others all have higher-than-average capacitance, seemingly in correlation to their outside diameter. I know that is probably not a real correlation, it just looks like one.
Click to expand...
If you are just going by the total diameter of the cable, your results are not valid at all. You don't know what is jacket thickness, what is dielectric thickness and what is plate thickness/area. You need to at least visually identify everything, if it can't be accurately measured.
 
#20
If memory serves, this goes back to the days before esoteric boutique cables and when there were only a few accepted instrument cable designs and material choices. Those cables were measured and it was determined that somewhere around 18.5' the high-frequency loss due to capacitance became noticeable/audible in the context of passive guitar/bass outputs. Obviously in this day and age there are a vast array of cable designs and materials that could increase the effective length of the cable not to mention buffered instrument outputs.

Now, if I could only remember what issue of Mix this came from...and from what decade.
 

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