Instrument cables rated and compared. A buyers' guide!

[getBAK]

Sad to report that Caufield Cables is no more... what are folks liking for high quality touring (not $200 studio) cables these days?
I tend to go braided, don't mind spending $75 for a good 15' cable if it's durable.

 

[crucislancer]

Sad to report that Caufield Cables is no more... what are folks liking for high quality touring (not $200 studio) cables these days?
I tend to go braided, don't mind spending $75 for a good 15' cable if it's durable.

I use Rattlesnake cables for all my cables. Great product!!

 

[blr2]

In order to understand why cables may sound different, we should look a bit deeper into theory.
In passive instruments, the serial impedance and inductance of the pickups, and the parallel capacitance of the cable make an RLC low pass filter. The main problem is not that much the cutoff at high frequency, but the fact that it is preceded by a sharp boost at the filters resonance frequency. It is this resonance frequency peak that is audible. All else being equal, the higher the capacitance the lower the resonant frequency. This is illustrated in the graph below:

Here, I plotted the resonance frequency vs capacitance for a filter with impedance of 10 kOhm and inductance of 5.5 H. These are typical values for something like a P-pickup.
As you can see, for cable capacitance >200 pF, this resonant peak occurs well within the range of the bass harmonics, and it would be audible.
Good instrument cables typically have a capacitance <100 pF/m (about 30 pF/ft), with the best of them around 50-60 pF/m. However, even some expensive cables measure >100 pF/m. Imagine a 6m (20 ft) of one such cable, having a total capacitance of say, 700 pF. The resonant peak of the resulting RLC filter woud be about 2.6 kHz, i.e. somewhere in the high mid range. You'll get several dB boost around that frequency, followed by a rolloff above that frequency.
Now, if we take 3 m cable with a total capacitance of 150 pF (very good ones can really measure that low), we see that the resonant peak occurs above 5 kHz, where there is very little in terms of bass harmonics. Such cable, compared to the higher capacitance one from the first example will sound brighter and cleaner. There is more to it, such Q-factors, but I'll stop here.
Surely, there is more to instrument cables than just capacitance (noise rejection, flexibility...), but I hope this will help to clear the matter of instrument cable capacitance and sound even further.

 

[Romain909]

In order to understand why cables may sound different, we should look a bit deeper into theory.
In passive instruments, the serial impedance and inductance of the pickups, and the parallel capacitance of the cable make an RLC low pass filter. The main problem is not that much the cutoff at high frequency, but the fact that it is preceded by a sharp boost at the filters resonance frequency. It is this resonance frequency peak that is audible. All else being equal, the higher the capacitance the lower the resonant frequency. This is illustrated in the graph below:

View attachment 7311144

Here, I plotted the resonance frequency vs capacitance for a filter with impedance of 10 kOhm and inductance of 5.5 H. These are typical values for something like a P-pickup.
As you can see, for cable capacitance >200 pF, this resonant peak occurs well within the range of the bass harmonics, and it would be audible.
Good instrument cables typically have a capacitance <100 pF/m (about 30 pF/ft), with the best of them around 50-60 pF/m. However, even some expensive cables measure >100 pF/m. Imagine a 6m (20 ft) of one such cable, having a total capacitance of say, 700 pF. The resonant peak of the resulting RLC filter woud be about 2.6 kHz, i.e. somewhere in the high mid range. You'll get several dB boost around that frequency, followed by a rolloff above that frequency.
Now, if we take 3 m cable with a total capacitance of 150 pF (very good ones can really measure that low), we see that the resonant peak occurs above 5 kHz, where there is very little in terms of bass harmonics. Such cable, compared to the higher capacitance one from the first example will sound brighter and cleaner. There is more to it, such Q-factors, but I'll stop here.
Surely, there is more to instrument cables than just capacitance (noise rejection, flexibility...), but I hope this will help to clear the matter of instrument cable capacitance and sound even further.

Absolutely - very interesting.

You mention 10khz. If I am correct, that’s only when you have the instrument’s tone knob wide opened. If you roll the tone knob, it should drastically increase the impedance. Correct me if I'm wrong.

Also, this is the very reason why I prefer to play with active instruments (even though passive instruments have a great sound and are much easier to use). The output impedance is so low with active pickups (since the preamp acts as a buffer) it will shift the resonance frequency of the RLC filter in the 20 or 30KHz. Even if the cable has an average capacitance, your tone won’t be noticeably affected by the cable. Then, if the signal is too bright, I still can roll off the highs or EQ the signal - but at least I have the choice to keep them or not.

 

[blr2]

Absolutely - very interesting.

You mention 10khz. If I am correct, that’s only when you have the instrument’s tone knob wide opened. If you roll the tone knob, it should drastically increase the impedance. Correct me if I'm wrong.

10 kOhm is about the right source impedance of a P-bass with both controls wide opened. At any other position of the knobs it is higher, it could be much higher.

 

[Romain909]

10 kOhm is about the right source impedance of a P-bass with both controls wide opened. At any other position of the knobs it is higher, it could be much higher.

Yeah, I remember seeing a french guy on Youtube talking about capacitance and impedance with a PBass and with tone all the way down, the impedance was like 200KOhm. The video has been removed since unfortunately.

This explains why it is extremely important to have great short cables if you want to use a passive instrument.
If it is active, it almost doesn’t matter.

 

[FretRiff]

This explains why it is extremely important to have great short cables if you want to use a passive instrument. If it is active, it almost doesn’t matter.

... for a direct passive connection going straight into an amp, absolutely true.

But most people connect to pedals of some kind, and if they have a buffer it provides a low output impedence which acts like a mini-preamp or active circuit at the front of the chain, making cable length between the pedal and the amp almost irrelevant. So get a tuner pedal with a buffer and don't have too long a cable from your passive bass to the tuner and you're good.

 

[blr2]

... for a direct passive connection going straight into an amp, absolutely true.

But most people connect to pedals of some kind, and if they have a buffer it provides a low output impedence which acts like a mini-preamp or active circuit at the front of the chain, making cable length between the pedal and the amp almost irrelevant. So get a tuner pedal with a buffer and don't have too long a cable from your passive bass to the tuner and you're good.

True, providing at least one pedal has a buffered bypass. In any case, it's a good idea to keep cables short. Longer cables are more likely to pick up noise and interference as well.
That said, some people like "the sound" of high capacitance cables. I've seen people explaining how their 30 ft coiled cables sound vintage. These cables can have a capacitance in excess of 1 nF. Connected to something like a P-bass, the resulting filter will have a broad peak around 2 kHz and cutoff above 2.5-3 kHz. The sound is often described as warm, full, vintage...

 

[AchimII]

We have a similar thread on a local German board. Which reminds me on something…

According to the oldest pics from 2003, where I used it already, somewhere in 2002 a fellow Pitter had bulk cable in different colours and straight/angled jacks and offered to build instrument cables.

Now, I learned that the biggest risk for cables are guitards, so I ordered some in red, 6 m, straight/angled and straight/straight. These are still in use w/o any problems, aside from one where I ruined a plug when closing the Bass case while the plug was inside the metal frame.

Excellent! Whoever has build them, thanks!