Cable resistance - a bit OT

[Phorhas]

hi, this is a bit off-topic and maybe some of you gus can help me or direct me to places that will

what is a good resistace for guitar and speaker cables?   -or, how high a resistance is tone degrading

well, while on the subject, what is considered "good capacitance"?

Regards,
Dan

[Herr Masel]

The only thing of value I can say about this is that higher value resistors (or thicker cables) retain more high end frequency that smaller/weaker values. You could just measure your guitar cables with your DMM to see what their values are.

[brett]

Hi.
This is superficially simple, but I suspect it's quite complex.
Resistance is not usually an issue, as far as I'm aware.  Your pickup etc has very high impedance relative to the cable (10k or more).
Capacitance is a major issue because it sucks tone.  Capacitance increases with less distance between the conductor and the shield.  So fat cords should be better.  In practice, a more practical option is usually a short lead to a buffer.
have fun

[niftydog]

NB; resistance is rarely the problem, impedance is what you really want to know - so a multimeter test is going to be almost useless I'm afraid.

what is a good resistance for guitar and speaker cables?

zero!

well, while on the subject, what is considered "good capacitance"?

zilch!

or, how high a resistance is tone degrading

Talking impedance rather than resistance, it will depend on the other impedances in your system and how they interact. Straight resistance will just attenuate the signal - but you'll never encounter pure resistance in a cable - there's always an impedance involved. In reality you can't get zero impedance cable either, all you can do is buy the stuff with a comparatively good spec - and personally I don't really fuss over my tone enough to know the answer to that off the top of my head. But, a quick scout of the major manufacturers (belden, canare etc) and some price checking and you'll soon find the good stuff - be prepared to pay for it though!

[formerMember1]

george L's are really thin, and they have the best high end of any cable IMHO

I like KLOTZ lagrange though, cuz they have more bass, lower noise stronger

[aron]

The thing I don't understand is why so many bass players can hear the difference with so many cables. AFAIK, most modern basses (the ones I am talking about) are buffered, IC-based preamps. Yet they really hear differences in the clarity (i.e. high end).  Any ideas?

[Phorhas]

hype? ad mojo? you know how it is... I bet that in a blind test they won't be able to tell differance. a cable's freq. response is flat up to a point where it starts to roll off highs. I guess that a goood cable with a well bufferd bass should have a flat response all the wayup the human hearing range.

Quote
what is a good resistance for guitar and speaker cables?

zero!


Quote
well, while on the subject, what is considered "good capacitance"?

zilch!

Yeah, I know that that's the ideal, what I meant what are some real life numbers, what are considered to be good cables?

[Steben]

Capacitance of the cable is major issue IMHO.

Pure resistance wouldn't be that bad in theory: it would damp the total signal, requiring more amp boost and thus boosting the highs too again. Yet higher resistance in series with signal gives higher noise of course so no option.

[Rob Strand]

> Yeah, I know that that's the ideal, what I meant what are some real life numbers, what are considered to be good cables?

Guitar and Speaker cables have different requirements.

The concept of the cable having a frequency repsonse is not useful.  The cable has "characteristics" and these interract with surrounding devices (pickups, microphones, speakers & amps)  to produce detrimental effects.   What characteristic is imporant depends on the surrounding device.

Guitar:

Resistance makes little difference; you couldn't make the conductors thin enough to make a difference.
Capacitance is the problem, it attentuates the highs.   A total of 220pF to 470pF is the point where is something just noticeable with A/B testing, and 470pF to 1nF
noticeable, beyond that  definitely noticeable.  Cables have capacitances in pF/m or pF/ft.  Short cables don't present a problem, long cables you have to make
sure the cable you use has low enough pF/m.  Warning: some high quality mic cables can have very high pf/m.  Microphones have a low impedance
compared to guitar pickups and hence the capacitance has less effect.  Guitars with preamps are highly immune to cable capacitance since the cable capacitance doesn't load the pickup itself.

Speakers:

Resistance is the key parameter.  It depends on the impedance of the speaker high impedance speakers are less effected by cable resistance.   A resistance of less than 0.5ohm would be hard to detect  (possibly 1ohm would be an upper limit).

Capacitance and inductance usually have little effect unless the cable length is very long.   Some niavely designed ampliifiers have problems with too much capacitance.  Inductance comes into play over 5m -10m length.


There will never be a magically ideal cable.  The resistance is largely determined by the copper diameter.  The capacitance and inducance is a combination of conductor sizes, conductor spacing and the covering material used.  It's all determined by physics and cable geometry.

[niftydog]

what I meant what are some real life numbers, what are considered to be good cables?

personally I don't really fuss over my tone enough to know the answer to that off the top of my head.

Sorry I can't point to any specific specs , but comparing the cheapo stuff to the good stuff would be where I would start. (Sadly, the cheapo stuff rarely has specifications though!)

...buffered, IC-based preamps. Yet they really hear differences in the clarity (i.e. high end).  Any ideas?

Well, perhaps they're (purposefully?) not the greatest buffers out there! Maybe they strike a compromise between "normal" high output impedance passive basses and "ideal" low output impedance buffers. Like, if you had a really low output impedance bass but no "active" input option on your bass amp you could be in trouble!

The most overlooked thing in this equation is the connectors. Ever seen a jack plug with a capacitance specification?! Nor I! I wonder if that's got something to do with it as well...

[JimRayden]

There will never be a magically ideal cable.  The resistance is largely determined by the copper diameter.  The capacitance and inducance is a combination of conductor sizes, conductor spacing and the covering material used.  It's all determined by physics and cable geometry.

I bet it's quite possible to get really close to that ideal cable. Maybe a vacuum construction where the electrons can move around at light's speed.

Oh right, we already have optical cables. Can anyone here talk about the possibility of the use of optical cables for guitar? Can they be used for analogue signals? I bet it would be VERY close to a zero-hum zero-capacitance zero-resistance solution.

-----------
Jimbo

[niftydog]

Optical cables do have great benefits, but the signal integrity benefits largely come from standard forward error correction algorithims that were originally invented for use on copper cables. Ethernet being a prime example of a digital technology that can use optical fibres but often doesn't because the cost / benefit analysis doesn't warrant it. So, I guess what I'm saying is that in order to gain the max benefit from optic fibres, you need to go digital.

And like all communications systems, the audible frequency range is not well suited to transmission. (Optic fibres are effectively transmission lines just like coax, waveguides or the atmostphere.) There are other problems associated with transforming the electrical signal into a light beam. Pulsing an LED or laser light source is easy, making it's light output linearly track a complex sine wave is somewhat more difficult. Then you're faced with similar problems at the detector end.

Besides all of this, I doubt anyone's making light sources or detectors that would be suitable and fibre is expensive and fragile. Oh, and you thought doing good solder joints on your jack plugs was hard? Try terminating a fibre and you'll rethink your position on the matter!

So yeah, you're right, but the physical properties of a cable can be overcome simply by going digital in the first place - the extra step to optics isn't necessary.