You should go to the website “Vintage knob” for baseline info. I believe the dp3000 was a midrange model in the first of two series of DD turntables made by Denon. The top model was DP6000. You should check me out on this, but I think that early series did not feature quartz lock referencing for speed control. The idea to use a quartz crystal reference entered the field sometime in the late 1970s. After that Denon created a whole new series of turntables using double digit alphanumeric code (DP80 is tops among the commercial series; there were much more expensive studio models) that did feature quartz lock for speed reference.The early series and the later series are pretty much identical looking from the outside. In my view however the series that incorporates quartz referencing for speed control are a bit superior.