i purchased a very nice vintage Pioneer Pl-560 turntable w/ a Grado GT cartridge. During the playing of some records i hear distortion from mainly the left channel. I have adjusted all aspects of the turntable ie; leveling' azimuth, balancing the tonearm, etc. I guess what I'm trying to determine could this be due to the cartridge failing or is something else the culprit. Hoping some one can give me some insight.

Shawn

It's possible that the stylus is damaged/worn on one side. If you can take a look at it with a high magnification lens, check that it looks symmetrical when viewed head-on. Since you bought this deck used, it might be a good idea to replace the stylus in any case, unless you know for sure its history. A worn/damaged stylus is the quickest way to destroy your LPs.

OK, assuming you have a stylus in good condition, then more distortion on one channel than the other is typical of incorrect azimuth (which you say you've checked) or incorrect anti-skating. If there is more distortion on the left, then the anti-skating is likely to be too high (assuming that the channels are correctly wired). Try setting the tracking force to the maximum recommended (I did a quick search but couldn't find what this is for the Grado GT), then adjust anti-skating afterwards. If there is more distortion on the right channel, increase the anti-skating; if there is more distortion on the left, decrease it. You're aiming for an equal amount of distortion (ideally none!) on both channels, when playing the middle section of an LP. You'll find that the distorion balance might shift at the outside and/or inside of the LP, depending on the way that anti-skating is implemented, so set it optimum in the middle so as to get the least imbalance across the LP.

I had a lot of channel imbalance trouble once from a new cartridge that turned out to have a twisted cantilever, pointing the tip of the stylus somewhat towards the inside groove. This is more-or-less an azimuth error but few tonearms have any azimuth adjustment. It was not possible for me to tell what was going on from the normal alignment procedure. Eventually I found it with the cartridge off the tone arm where I could look at it with a 16X lens from straight on at the front. Even then it took me a while to recognize the problem.