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Dude Music Musicology

This article explains all you need to know to make an informed decision when buying your next guitar or instrument cable, bypassing player myth and salesperson snake oil and replacing it with audio engineering scientific fact.

The magnetic pickups in your instrument if passive (unpowered unlike active pickups which require a battery) rely upon the magnets and coils in the pickups combined with the string vibration to create a very weak electrical 'push' of electrons (if you were to think of your pickups on your guitar as being electron pumps) due to your string vibration.

If you push the electrons hard enough into a path of low resistance i.e. to an input with infinitely high input impedance there will be no significant difference between copper cables across the audio spectrum as regards 'flat' frequency response especially at guitar cable length of tens of feet rather than hundreds.

Without an onboard preamp though it is your pickups that have to push electrons through your cable for however far that is and your passive pickups are inductive.

What we want ideally is a cable that has minimum resistance to the electron flow and we know that copper is an excellent conductor of electrons and is malleable so that would be a good choice for sure.

Our ideal practical guitar cable then is a length of solid copper running from our pickups to our instrument amplifier for minimum resistance and cost effectiveness or we could also use silver which is a little more conductive than copper but much more expensive.

However due to the electrical resistance of even copper we still want this length of copper to be as short as possible, like an inch or so. In the real world however we have our length of copper cable at say three metres allowing for a drop from guitar to floor, then along the floor, then up to the amplifier head or combo input.

So we go ahead and plug in with a 100% solid copper cable and 1/4 mono jacks also of copper which as it happens have been cold welded to the cable or were melted in as part of the cable construction.

There are some problems!

1. The copper is entirely exposed to oxygen in the atmosphere and starts to turn to powdery green copper oxide especially when we spill beer on it!

2. It isn't stranded so it isn't as felxible as it could be.

3. The cable is picking up all sorts of other electromagnetic fields from mains power sources, radio frequencies, the universal lot and is making a hell of a noise before we even play a single note.

Herein lies the rub with guitar and instrument cables and all other forms of communication. We are sending a signal and that signal must travel a distance in the real world without interference or with as little interference as possible.

We have two ways of achieving clear communication, these techniques which may be used in combination:

1. Send a very strong signal so powerful that the interference signals are negligible in comparison.

2. Protect the signal from interference signals throughout as much of the distance of its journey as possible.

We have established that sending a very strong signal is not possible with passive guitar (and other instrument) pickups, so we are left with protecting the signal from interference which means we must protect the weak signal along its journey.

In short we must cover the copper with shielding to:

1. Protect against corrosion anywhere a non-permanent contact must be made i.e. the termination jack plugs.

With regard to the termination jack plugs, we want them to have the best possible connection between the cable copper wire and the jack socket connectors where the guitar signal flows. This is achieved best by having as much copper in the jack as possible but then coating it with a less corrosive contact material like nickel.

Nickel is a decent conductor and is quite hard and so is a good choice. When it does corrode over time it can be cleaned up with a little electrical contact cleaner or isopropyl alcohol and a lint free rag or even very fine oil free steel wool.

Gold is less corrosive but is rather soft, and is ideally used in connection with the same material on both sides of a connection otherwise a softer material always rubs away on a harder material. Gold is best between gold to gold contacts which improves the cycle wear issue (and in fact this is the only time gold is ever specified by audio engineers).

2. Protect against signal interference along as much of the length as possible.

This is where things get interesting and where we find our guitar tone gets too muddy or even too bright!

To protect our cable against electromagnetic interference we wrap it in shielding, and we terminate this shielding at both ends of the cable, it's basically a second cable for all the crap we don't want getting onto our signal cable! If you like driving a car think of it like a lane for buses, lorries, cyclists, caravans and really old drivers! If you are a cyclist think of it like a lane for motorised vehicles! ;O)

The trouble is that when we add this lane of shielding we pay a price with extra 'capacitance'.

Onece you know that a cable has good shielding and is well made, cable choice all comes down the to capacitance and resonant frequency.

Capacitance can be viewed in practical audio transmission terms as a type of electrical resistance which has more effect on higher frequences than lower ones. Lots of capacitance over the cable length starts to act like a low pass filter (high end roll off) on our guitar or instrument signal making it sound dull and in addition like a second order high pass filter the eq curve has a resonant frequency peak which boosts the signal just before the frequency where our high end begins to slope off! This capacitance is part of a tuned circuit with a passive pickup that has it's own internal capacitance and resonant frequency.

So our 'best' cable:

1. Offers maximum long term screening against interference.

2. Given it's length vs capacitance per unit of length (measured in pico farads pF per meter or foot) gives a roll off of upper frequencies with a resonant bump that falls in a part of the instrument sound spectrum that we think sounds good to us!

So here is how to find a cable that is right for you, excluding the effect of pedals, true bypass or not (which we will get to in another article!).

The 'Best' Cable 'Shootout' for premier quaility tone!

1. Make sure it is well enough protected against interference... on stage over long distances getting trodden on and pulled about surrounded by all sorts of electromagnetic mayhem, or in a studio with lots of other electronic equipment emitting electromagnetic radiation.

2. Make sure the cable manufacturer has made the protection in such a way that it doesn't 'break down' quickly as you'd be surprised how inferior materials will quickly cease to measure up to their newly manufactured claims.

3. Calculate the frequency of peak resonance and point of high end drop off by using length and capacitance to find out overall capacitance in combination with your particular pickup.


On the basis of finding a cable with long lasting shielding with low capacitance I recommend Sommer Spirit XXL and Spirit LLX cable from Germany. Low capacitance will keep the high end intact the best. They are excellent cables with low capacitance.

If your pickup is output harsh by design you may need to move the resonant frequency lower with more capacitance by using a longer low capacitance cable or short high capacitance cable though most premade cables on sale these days are low capacitance.

On the basis of finding 1/4 jack connectors I recommend G&H copper core jacks and Hicon (a division of Sommer) pancake jacks or Switchcarft pancake jacks for low profile pedal patch cables.

Coming soon... Best Guitar Cables and Pedal Patch Cables for Pedalboards by SHOOTOUT! UK



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