It is counter intuitive that a relatively soft vinyl record can wear out an extremely hard diamond needle. But the act of playing a record results in some extraordinary demands on both the stylus and the record. First, the tip of the needle that goes into the groove is very small – smaller than a normal human hair. The shape of an average elliptical diamond tip is described as .3 mil x .7 mil. That is .0003 inches by .0007 inches. However, the area of the tip that actually contacts the groove is much smaller. Because the contact points are so small, they can generate a force on the groove wall of up to 35,000 pounds per square inch when tracking at 1.5 grams. Additionally, when the stylus is working hard to play the record (when the music is loud or very dynamic) those tiny contact points may reach temperatures of 300 to 500 degrees Fahrenheit or more.
Now, let’s add one more factor. If you straightened out the groove on one side of a record it would be, on average, 1500 feet long! Said another way, after playing only one complete album, your stylus will have traveled more than one-half mile. Assuming that the average record has a total playing time of 45 minutes, 500 hours of use will equate to about 666 albums. This means that your needle will have been dragged through over 300 miles of vinyl.
How long will your diamond stylus last?
Under normal conditions your diamond needle should last between 400 and 800 playing hours – 500 hours is probably the average. The actual number of hours will depend on many factors including: proper alignment of the diamond, correct set up of the cartridge and tonearm including the overhang, azimuth, tracking force and the anti-skating adjustment, and to some extent the condition of your records. More on turntable calibration later.
How do I know when it’s time to change my stylus?
The obvious answer is that you want to replace your stylus before it starts to damage your valuable vinyl collection. The only accurate way to evaluate the condition of your needle is to examine it under a high quality, stereo optic microscope. As you play your records the tip of your diamond needle will develop flat spots. As the flat spots grow larger, your needle will begin to resemble a chisel. And in fact it will act like a chisel, forever removing valuable music from your record grooves.
As the diamond wears, and the flat spots get larger, the stylus will have difficulty tracking the high frequencies. Your first audible sign of stylus wear will be distortion of instruments like cymbals and violins. Unfortunately, by the time you hear the distortion your needle may already be shaving the vinyl off your record grooves.
At Breier Audio/Video we have a research caliber stereo optic microscope made by Wild Heerbrug . The microscope was made in Switzerland using German optics. At 100X magnification you can see the exact condition of the needle. We recommend that you bring your stylus in for evaluation after the first 200 hours of use and then every 100 hours thereafter. (It is worthwhile to examine a new stylus before installing it into your turntable as there are occasionally manufacturing defects which can cause the stylus to be defective, resulting in poor sound at best and extreme record damage at worst.)
In addition to monitoring the wear on your diamond needle, regular inspections sometimes reveal problems in the calibration of the turntable and tonearm that cause the stylus to wear out prematurely. For example, if the tip of the diamond is wearing unevenly it may be due to the incorrect adjustment of the anti-skate mechanism. Once you know that the wear is uneven you can take steps to correct the problem which will maximize the life of your stylus and your records and improve the sound of your music.
Bring your diamond stylus to Breier Audio/Video anytime for a FREE examination using our laboratory grade microscope.