Part 5: Binding Posts and Cable Terminations

Binding posts vary hugely in quality, from the tiny spring-loaded, push-in terminal strips on cheap loudspeakers to massive, custom-made, machined brass posts plated with exotic metals. Poor binding posts not only degrade the sound, they also break easily. When shopping for power amplifiers and loudspeakers, take a close look at binding-post quality.

The most popular type is the five-way binding post. It accepts spade lugs, banana plugs, or bare wire. Some five-ways are nickel-plated; higher-quality ones are plated with gold and thus won't tarnish. Five-way binding posts should be tightened with a 1/2" nut driver, not a socket and ratchet or wrench that could easily overtighten the nut. The connection should be tight, but not to the point of stripping the post or causing it to turn in the chassis. When tightening a five-way binding post, watch the inside ring or collar next to the chassis; if it begins to turn, you've overtightened the post and are in danger of damaging the power amplifier or loudspeaker.

Custom posts of heavy-duty machined metal are more robust than five-way posts-they can accept more torque without stripping or coming loose in the chassis. Custom posts are often found on the most expensive equipment. The amplifier rear panel shown in Chapter 6 (Fig.6-10) uses high-quality custom posts.

Some binding posts have such a large center post that spade lugs won't fit around them. These posts have large holes in the center for accepting large bare wires or banana jacks. Although these posts are expensive and appear to be of high quality, they're inconvenient to use. If your equipment has this sort of post, the best solution is to terminate your loudspeaker cables with oversized spade lugs. Most spade lugs have a distance between the prongs of 1/4" to 3/16"; oversized spades have prongs 5/16" apart-enough of a difference to fit the large-holed posts.

If you have a choice of bare wire, banana plug, or spade lug on loudspeaker cable terminations, go with the spade lug. It forms the best contact with a binding post and is the most standard form of connection. Many European products provide only banana jacks, forcing you to use sonically inferior banana-plug terminations.

You should be aware that any termination slightly degrades the sound of your system. Consequently, some audiophiles have gone to the trouble of removing all plugs, jacks, spade lugs, and binding posts from their systems and hard-wiring everything together. This is an extreme measure and makes switching equipment difficult or impossible. Hard-wiring is an option, but not one that should be undertaken without considerable deliberation and technical expertise.

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