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In the Forum: Analog Playback
In the Thread: Ultimate Turntable
Post Subject: Feedback LoopsPosted by hagtech on: 3/2/2008
I believe a lot of the issues with earlier DD tables was that they were all servo controlled. That is, a feedback loop kept the average velocity constant. As a musical passage of complexity would slow the platter, the loop would respond with more motor torque and speed it back up. Hence, the platter speed was always chasing its tail. So you didn't have a passive reaction to stylus drag, but a reactive one, adding a new pitch signature. Speed up, slow down, etc. Always chasing. And it depended a lot on the natural frequency response of the feedback loop. Heavier platters required a slower loop.
DD itself might be ok, if not servo'ed. I am curious as to what the changes were that made the later Technics sonically improved.
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