I got a new Technics 1200, brought it home, plugged it in, and everything worked fine except the audio sounded very wrong.
It sounded exactly like an audio signal sent through a tight compressor/Limiter. The audio was fine until bass came in, but when there was a lot of bass it completely killed the rest of the signal just like when you send too much bass through a too-tight limiter or soft clipper. The treble sounded like it was being modulated by the bass. It sounded nothing like a grounding issue.
I tried everything to fix the problem. I sent the table through different channels in my mixer, I switched cartridges/styluses, I tried several different records. My counterweight, arm height, and cartridge were all perfectly set. The problem still lingered even though everything was fine on my reference table of the exact same make. I spent hours (hourS - as in more than 2) trying to find the problem.
Then my father explained how it could be an a/c power issue and how he paid A LOT for a nice surge protector/power supply for his hi-fi system. He said to switch power supplies. I did, and the problem disappeared. Everything is now working perfectly.
What the gay!?!
The turntable didn't show any power problems. The Motor, slider, buttons, LED's and the strobe all worked perfectly. How could that possibly effect only the audio out signal while not effecting any other electrical units in the table? The signal on a turntable is sent out even when the power is off, so how the billy could the power possibly effect it?