Cable Theory


Various factors determine the sound of a cable.


The main electrical parameters influencing the sound of a cable are capacitance, inductance, and recistance.The design and geometry of a cable determines these values. Inductance (L) works as a low-pass filter, cutting the high frequencies. Capacitance (C) in a cable works as a high-pass filter, cutting out the low frequencies. Resistance (R) depends on the conductor material and thickness. Resistance transfers the music signal into heat, we dont want that.

Conductor material is important, be it copper, silver, aluminum or gold. Silver is actually a better conductor than gold. The reason why many conectors are gold plated is because of its resistance to oxidation. The isolation surrounding the conductor is of almost equal importance, because the signal does not only travel inside the conductor- An electromagnetic field forms around the conductor, expanding in size and power with the pulse of the music. The isolation material interferes with this electromagnetic field, and alters the signal transfer. The mambo cable uses air as the main isolator.  This is difficult to acheive in mass production so most cable manufcturers extrude a plastic coating over the conductor. This is not good for the sound - but it is cheap.
 

From High-school physics we know that a magnetic field induces current in a nearby conductor, wich is the basis of a dynamo or transformer.  The positive and negative conductors, in a cable influence each other in the same way. The Mambo cable takes advantage of this fact and uses the its own magnetic field to drive the signal forward, not counteracting itself as it does in many cables.

 


Signal and speaker cables work under different conditions.
 

A Signal cable connected between a cd player and an amplifier carries virtually no current. The varying voltage does the trick. The maximum signal output level for a typical cd player is 2 volts peak, and the average signal is much lower. Typical input impedance of a power amplifier is 10 thousand ohms, or several hundred thousand ohms for some tube power amplifiers.

 

Taking the lowest impedance values from the above, the maximum current seen is 2Volts/10k ohms- 200 micro-amperes or 0.00002 Amperes. This would not even light up a flashlight


A speaker cable is driven by relatively high voltages- depending on your amplifier, 50 Volts is not unusual. A typical speaker is 8 Ohms dipping down to 3 Ohm. This means a speaker cable must carry current impulses of up to 50Volts/3 Ohm- 16.66 Amperes. This could blow the fuses in your home - as some of you may already know ;-)

 

In addition to being thicker -more conducting area in a speaker cable, our speaker and signal cables are constructed differently- different geometries


Our signal cable has ultra low capacitance and moderate inductance. The circuit it forms part of has an impedance of tens of thousands of ohms, so the inductance of the cable contributes little to the overall.
 

Our speaker cable is just the contrary; very low inductance and  moderate capacitance. Because any speaker with a crossover- and thatís practically all commercial speakers, have at least one capacitor, the one working as a high-pass filter for the tweeter. The voice coils in the speaker together with the inductors of the crossover makes the inductance of the speaker.  The crossover for the tweeter does not have an inductor, but a capacitor. This is where speed matters - 20 kHz or more.  We donít want to add inductance in that circuit.
 

The best way to keep inductance, capacitance and resistance low is to keep the cable short.

Half the length of the cable equals half the capacitance, inductance and resistance. The best cable is no cable-   So try to keep them short !