Vintage DD turntables. Are we living dangerously?

Lew if you’re not familiar with gun metal CU-500 mat from Micro Seiki i’m pretty sure you know at least their CU-180. However the CU-500 is thicker and heavier (2.7 kg) and very rare along with their super heavy gun metal record clamp Misco Seiki ST-20 (not as easy to find as Micro Seiki ST-10).

I don’t have any pictures of my stuff on audiogon, but this is picture of my own Misco Seiki CU-500 to check in high resolution on SP10mk2. And this is another view on the same CU-500 on the same deck.

And old picture of my teak wood plinth for SP10 with EPA-100 and Technics EPC-100c MK3 cartridge retipped by AXEL in Germany (curently for sale or trade btw:).

2.7 kg!!!!!!  That is nearly doubling the weight of the entire platter of an SP10 Mk2.  I would never do that to any DD turntable.  You could probably get away with it on a Mk3, because the base platter weighs 22 lbs to start with.  The servo is tuned to the rotational mass of the platter. You may well have enough torque to get that much extra mass moving, but you are probably losing something in terms of performance.  Perhaps Peter and JP can chime in on this subject.  Lots of modern day users of vintage DD's do these things. Keep in mind that M-S made the mat for their belt-drive turntables. In any case, I won't be looking for a CU-500 for my Victor.

The SP20 sounds like an economy version of SP10 Mk2.  You sacrifice 78 rpm, probably some electronic sophistication, and the cost of an outboard chassis, to save some cost.  I'm sure it's excellent.

Forgot to say that my TT101 is running but not "up and running". Time got away from me this weekend, and I have yet to mount a cartridge. I did install the chassis into the QL10 plinth, which I have modified extensively with metal arm board and metal re-enforcements underneath the MDF stock plinth, to add mass and structural rigidity, and constrained layer dampening.

Has anyone unearthed any data on the Victor UA7045 tonearm, particularly its effective mass?  I have an FR64S mounted on the Victor plinth, but I might want to go back to the UA7045, if it would be a better match for a higher compliance cartridge than is the FR64S.

Lew, re: metal mats

Some time ago I believe it was Raul who recommended the Audio Technica AT666.  That is a metal mat with vacuum hold down.  His preference was simply as an added mat, ignoring the vacuum.  I looked that up and it weighs 1.4 kg, still pretty heavy but within the range listed in the SP-10 MK 2 manual.

lewm
03-14-2016 5:54pm
2.7 kg!!!!!! (...) Perhaps Peter and JP can chime in on this subject.

If you go to a show where Pass Labs have their source setup, you'll likely see a MKII with an ~8kg stainless steel platter.  My understanding is their 'tables have been setup this way for years without issue.  Stainless platters for the MKII show up on Yahoo every once in a while.

I had one (a platter) here for a bit on one of my MKII.  Takes a little longer to start and stop, but I didn't notice any ill effects.  I didn't measure any circuit parameters while running it - having a MK3, it was doubtful I'd even keep a MKII around.  W&F was about the same as the stock platter.

You'll see stainless platters show up on Yahoo every once in a while.  

I'd monitor the thrust pad a bit more often.