Gear Review: Behringer CT100 Cable Tester

When we're not writing for GuitarKitBuilder our time is spent running several rock music schools for kids. During a typical day of lessons and rehearsals the guitar and bass students are constantly plugging and unplugging our guitar cables from amplifiers and their instruments. As a result these cables take quite a beating and we need to test and repair cables on a regular basis. To make this chore a little easier we recently picked up a nice piece of gear that many guitar players and kit enthusiasts would also find handy.

The Behringer CT100 is a microprocessor-controlled cable tester that makes it easy to detect shorts, opens and, most importantly, intermittent connections in a wide variety of cable types. Let's take a closer look. This tester makes two initial impressions. The first is the low-price. Behringer's list price is $45 and the online price is typically around $30 but we picked ours up at Guitar Center on a sale for $22.

The second impression is how solid it feels - like a brick when you pick it up. A couple of other notes are that the CT100 comes with an attachable belt clip and uses two AA batteries. The panel is covered in jacks, switches and LEDs. The jack types are 1/4" (e.g. guitar), TT (tiny telephone/bantam), 1/8" (e.g. headphone), MIDI, XLR (e.g. microphones) and RCA connectors (audio/phono). The main connector types that is missing for us is the speakon connector used to connect high-power speakers to PA systems. But that's a small nit, especially in a high-featured, low-price unit.

When you plug a guitar cable into the two 1/4" jacks you get the test results on the matrix of LEDs in the lower-left corner. The jacks are actually stereo jacks that can test the tip (pin 2), ring (pin 3) and sleeve (pin 1) connections on a 1/4" plug.

If you're not familiar with tip, ring and sleeve terminology, the sleeve is the ground or shield connection. The tip is the signal lead for a mono connection, and the ring is the added signal lead for a stereo connection.

A standard (mono) guitar cable only uses the tip and sleeve, so the tester will show the ring and sleeve as connected together. When a good guitar cable is plugged into both jacks the display matrix will look like an "X" as shown in the photo. The matrix shows which pin of the input jack is connected, through the cable being tested, to which pin of the output jack. The center LED of the X-pattern shown indicates that the Pin 2/Tip of both jacks are connected. The four outer corners of the X-pattern show that the Pin 1 & 3 (sleeve and ring) are connected to each other.

However the test doesn't stop with just plugging in. As any guitar player knows, most guitar cable "failures" are noisy or intermittent connections that can drive us crazy. With the CT100 the microprocessor monitors the connection for brief open or shorted connections that the eye might not catch on the LED matrix. If any problem is detected, no matter how brief, it will show up as a steady lighted LED in the Intermittent column.

So the procedure is that once the cable is plugged in, move the cable vigorously in all directions to see if any intermittent problems are indicated. Our procedure is to flex the cable near the plugs, and then run a rough grip over the full length of the cable to uncover any problems within. The reset button is used to restart an intermittent test.

Overall we found the Behringer CT100 Microprocessor Controlled 6 in 1 Cable Tester to be a very effective and easy to use guitar cable tester.

The CT100 has many other features for other cable types and situations. You can use it to test a permanently installed cable where you don't have access to both ends of the cable at one location. A shorting-plug (not provided) is used in these situations. The CT100 also has a test tone generator at adjustable levels (+4dBu, -10dBV, -50dBV microphone level) and frequencies (440 Hz, 1kHz). The test tone can be used to check signal flow and to facilitate output level adjustments. It routes a test tone to the "+" pin (pin 2/tip) of all output jacks.

This is a handy device, not a precision instrument, as the output levels will vary somewhat with battery voltage. The CT100 will detect phantom power which is commonly used for condenser microphones, and also detects whether the XLR jack shield is grounded, meaning connected to the pin 1/sleeve.

Check out more about the CT100 on Behringer's website.