Direct Drive vs. Idler Drive vs. Belt drive

@chakster, thanks for the picture of the two samples of CU-180. I also have two samples with similar differences. I've always wondered if the one with the 'deep groove' was the original, like my blue note pressings! But in this case they sound the same....

@edgewear i don’t have a golden ear to detect any difference in sound between gunmental and copper, but from my two Micro CU-180 only one sample can fit into by Luxman platter because of this +/- 0.2 mm tolerance in diameter between the samples (color also different).

Regarding Copper versus Gunmetal you can read item description from the experienced Japanese sellers like Otomon here:

" This is a precision machined, Copper mat that offers an optimal platform for vinyl records. This was manufactured from special Gunmetal which was research and developed by Micro Seiki. It cut off vibration from outside and make sound more clear and better low frequency. "

And here is Gunmetal platter from the same seller. To my eyes they’re identical in color while the Astisan Fidelity pure copper mat looks different in color.

Anyway, i'm sure they are all good. 

I modified my mid-level belt drive Pro-hectic TT to use a non-stretch Kevlar belt and a small needle-bearing idler pulley to tension it. TT bearing noise is so low it’s virtually unmeasurable on my oscilloscope. 

Bob, how could the changes you describe have affected bearing noise?

alexberger,

unfortunately I have no experience with EMT DD drives.
the Airforce tables are well designed, they do not have an airbearing concept like Caeles or the Apolyt.

best
E.