Hi,
jsman, What are you using for a light source to check the strobe disc? If the light isn't stable you'll get strobe "bounce". Tom |
jsman, if you're using the KAB strobe light (and the batteries are good) you should be seeing a series of numbers that correspond with the speed the platter is spinning. So assuming you've got your turntable set for 33.33 RPM you should see a "33" displayed that is stationary (indicating steady speed) or floats slowly left or right depending on whether your turntable is running fast or slow. Not sure what you mean by "
the lines on the strobe bounce back and forth." Tom |
jsman, yes, it's the illuminated number icons that count. If there's drift, and you have a way to adjust platter speed, you can usually get the illuminated numbers to hold steady, plus or minus. I always make speed adjustments with the tonearm lowered and playing the first song of a LP sitting under the strobe disc. It's surprising how much stylus drag there is. If you don't have a way to adjust speed you can get a close estimate of actual speed and error using this technique posted at the KAB website: TO EVALUATE DRIFTING SPEED, [COUNT] THE NUMBER OF ICONS THAT MOVE IN AND OUT OF THE SPOTLIGHT IN 60 SECONDS. |
I replied to the OP already but I thought I'd add a comment about the calculations for platter speed from the KAB USA website. Please correct me if I have this wrong, but the platter speed calculation didn't mention that when the platter is running slow you have to account for it by either using a negative error, i.e., [1 + (-count/360)] x RPM, or, subtracting the error, i.e., [1 - (count/3600)] x RPM. Tom |
