I've read many postings about how important quality cables are for eliminating noise and preserving tone. What should I look for to make sure I'm buying a quality cable? I have a very good 10' main cable that is braided. The soldering looks good and it is wrapped in the right places and feels sturdy. Any other suggestions to make sure I'm buying good cables? I'm not crazy about my 6" pedal cables so I'm probably going to replace those soon.
The other two answers assume that you are using screw on connectors with soldered-in cable cores and don't really address the qualities of another type of cable on the market, which would be the do-it-yourself cables like George L's or Lava. Those types of cables tend to be slightly less expensive than a mega-store bought brand as you pay by the foot for the bare wire and for each connector but you have to build them yourself. These cables are typically assembled by stripping each end, jamming it into the connector--which is usually a very long needle housed in a 1/4" plug--ensuring that the braid is grounded, and screwing the end cap on to secure the cable connections in place. The way the cable works is when the needle is buried in a di-electric material surrounding a wire core it creates a connection to the other plug just like a soldered cable. I recommend having a multi-meter handy when you're building these--it takes the guesswork out of the process because you can check for a valid connection by using a diode test. When choosing a DIY style cable look for connectors that are easy to assemble and have long pins, easy to screw on tops, and high quality cabling.
The advantages of these cables are no different than a high quality soldered cable--with the added complexity of building it yourself. Typically makers of these types of cables cite lower capacitance as their main bonus, but there are soldered in cables that have the same qualities. One could argue that the connection between the cable and the plug isn't as good as a soldered in cable--which may be accurate--but I have never had any issues with any of the DIY types I have used over the years.
The trick with cabling is to get as few feet of cable as possible in between you and your amplifier. This is especially important if you don't have any line buffers on your pedal board or are using a true bypass looper. I always recommend to people to go with a DIY brand for patch cables because you can cut the cables the exact length needed to travel the distance from one pedal to the next in line on your board. This minimizes the total length of cable between you and your amplifier--which will make a huge difference in what you hear. High frequencies tend to attenuate across long cable runs which results in a muffled, muddy sound, and less cable will minimize that without having to add a line driver to your chain.
Low Microphonic Characteristics - This means that the cable should not easily produce audible noises from your amplifier when hit on the ground, or moved during playing. (A low quality cable will often times make a "thud" noise when hit off of the ground)
Sturdy Plugs - I recommend purchasing a cable with coated ends, so that the persistent bending of the cable at the ends that occurs during playing does not affect your sound.
Sturdy Look - This is one of those cases where you can judge a book by its cover. If it looks cheap, then it probably is cheap and you want to avoid it. Look for a quality coating on the wires, and sturdy end plugs.
Quality Brand Name - A brand can only become well known for quality products in one way; Making quality products.
Lack of Tone Loss - There should not be a noticeable loss in tone when using a cable that is a reasonable length of 20ft or less."
Connection quality. If the cable has a screw-on connector, unscrew and look at the connection between wire and plug. It should be securely soldered without excess or mess. On the other hand, gold connectors are a waste of money, all else being equal.
Screening. A good quality cable will be screened with braided copper or some form of conductive plastic jacket to decrease microphonic or other noise.
Capacitance. Lower capacitance equates to a greater ability to respond to changes in voltage, which means better tone and frequency response. This is more relevant for high impedance sources like passive pickups and effects with true bypass (with the bypass engaged) than active pickups and effects with an impedance "correcting" gain stage (non-true-bypass).
Remember to keep cables carrying high impedance signals to under 30ft. to prevent signal degradation.
Finally, judge a cable by its sound, not by its look. Don't pay for marketing, pay for actual quality. If you're halfway decent with a soldering iron, consider making your own cables. It's easy, cheap and fun.
From my experience, I don't trust a cable until I've tried it. Digitech has done pretty well for me, but if I generally head toward thicker gauge cables from more well known brands, I do pretty well. I recently learned that poor "shielding" on a guitar is really what gives that cruddy background buzz if too many stray signals are about...
Plain and simple, if there's a bad buzz, try some cables out, pick one, do some extra shielding on your guitar, and buy a noise gate.