Twl,
You know, I do enjoy the process, but I also see the journey as part of the hobby of analog reproduction. Spinning vinyl is not only rewarding in its own right, but it carries with it greater involvement on the part of the audiophile, from the choice of turntable, tonearm, and cartridge to the selection of music. Theres simply more to do as you know, which brings me, certainly, closer to the music. And then to share these experiences with others makes it all the more rewarding.
>>We are just trying to provide some insight that will help you to make your decisions about some of the details.<<
Thats for sure; theres a lot of detail. Putting together a very good analog front end entails an attention to detail; otherwise it would be very easy to make a very big mistake, like putting the wrong tonearm on the turntable.
DC motors have been used in turntables for sometime, especially direct-drive ones, which are not very popular at all for good reason lousy sonics unless the table costs nearly a million dollars. The direct drive model I once owned used a quartz controller to maintain consistent speed, or so said the marketing literature, and a built-in strobe to help with speed adjustment. All of this technology could not compensate for a lack of bass, dynamics, and presence of a black background. Instead my last turntable was more adroit at highlighting surface noise over inner detail and micro dynamics.
My concern about AC motors is the amount of shielding they have in order to reduce hum in cartridges, like the Grado Reference line, that have no shielding and are susceptible to turntable hum. Im glad the Teres doesnt use an AC motor. If I should ever decide to use a Grado cartridge, hum shouldnt be an issue, or at least thats what I have been told.
In addition to stylus drag, I also imagine that bearing friction and air friction affect speed consistency, but to a lesser degree. If the platter were spinning in a weightless vacuum, it should continue to rotate without any fluctuations in speed for ever. But you are right: the stylus will have the greatest impact.
Its interesting to note that stylus drag is accumulative; that is, as a record is played over a 20-to-30 minute duration, the speed will diminish over that time. Why is that? Its also equally interesting how an AC motor can achieve a speed lock without some form of a feedback sensing system that supplies the needed electrical pulses should there be any current drop in the AC line.
>>The bottom line is that the heavier the platter is, with more rotational momentum, the less likely that stylus drag will significantly affect the speed. With the heavier platters, even a TT which uses speed controls will not have to engage in compensating pulses to the motor very often, if the platter stays at correct speed in the first place.<<
This is a good argument for the lead-shot platter, and as a $350 upgrade, it seems to be a no brainer.
>>However, I do know that if something severe happened to the platter speed, that the controller would account for the change immediately.<<
Is the adjustment instantaneous or is there a lag time? If a lag exists, is it audible?
As for the acrylic platter, would it be possible to use a felt or Neoprene pad to reduce ringing in the upper midrange, or is that undesirable? Without the pad, the vinyl will be laying directly on the acrylic.