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http://www.sanderssoundsystems.com/technical-white-papers/cables-wpTo test interconnects; you do not need any test equipment. You can use your preamplifier to do the switching. You will need a "Y" connector so you can connect the two interconnects under test (let's call them "A" and "B") to the same component -- probably your CD player.
Note that the "Y" connector is the same for both interconnects, so even if you believe that the "Y" connector somehow corrupts the sound (they don't), the same corrupted signal will pass through both interconnects so the test will still be valid. We will only be listening for any differences between the interconnects, and you can hear that difference (if present) on any signal, even a corrupted and distorted one.
Inexpensive "Y" connectors can be obtained from Radio Shack. If you want audiophile grade "Y" connectors, Sound Connections International (phone 813-948-2707) sells beautifully-built, gold-plated units at reasonable prices.
Plug your "Y" connectors into the left and right outputs of your CD player. Connect one end of interconnects "A" and "B" to the "Y" connector. Do so for both channels.
Connect the other ends of interconnects "A" to one of your preamp line-level inputs (such as "CD"). Connect the other end of interconnect "B" to your tape monitor input. Do so for both channels. Be sure you don't reverse the channels. All line-level inputs on a preamp are identical, so it doesn't matter which ones you use.
You could connect the interconnects to any other line-level input on your preamp instead of "Tape." But the tape monitor inputs will allow to switch back and forth between interconnects by toggling the tape monitor switch instead of having to press different input switches, or rotating a knob.
Toggling a single switch
this is more convenient and makes it easy to do the test "blind" so you don't know which interconnect you are listening to. Doing the test blind is desirable so your personal prejudices don't influence the test results.
I understand that some audiophiles do not believe in blind testing. But really now, why do you need know the brand of the interconnects to hear differences between them? If they sound different, they sound different. You can hear such differences even with your eyes closed.
Blind testing offers the advantage of eliminating personal bias. Human nature is such that if you believe that a particular component will sound "better" (for whatever reason), then it will sound better. So to be sure that you do not deceive yourself, you should not know which interconnect you are listening to.
The test is easiest to do if you have a remote-control preamp so you can sit in your listening chair and simply push the Tape Monitor button on the remote whenever you want to switch interconnects. If you don't have a remote control preamp, then you may need an assistant to switch for you whenever you signal them (just wiggle a finger) to do so.
To do the test blind, press the tape button several times quickly so you get confused and don't know which interconnect you are listening to. If your preamp has an indicator light showing what you are listening to, then either put a piece of black electrical tape over the light or close your eyes while you do the test.
Testing is done by listening to music while switching back and forth between the two sets of interconnects as frequently or as infrequently as little as you wish. The idea is to try to hear any difference between the interconnects.
There is no time limit, you may switch whenever you wish and take as long as you want. If you think you hear a difference, you can go back and listen to the same section of music over and over and switch back and forth several times to be sure.
Some audiophiles believe that only long-term listening tests will reveal differences. If you believe this, then take as many days as you want to do your tests.
All you should do is listen for any difference between the interconnects without knowing which one you are hearing. If there is a difference, then you can later decide which sounds better to you. But initially, just listen for differences.
If you hear differences, others should hear them too. You will find that both "golden ear" audiophiles as well as non-audiophiles will both be able to hear the same thing you do. In other words, this test is very accurate and if differences are present, everybody will be able to hear them and agree.
