Vintage DD turntables. Are we living dangerously?

@lewm cu-500 on my sp10mk2 only improved the sound quality to another level of performance. One of the best upgrade i have ever made. 

Ok. If you guys sanction the use of platter mats that are way heavier than the original mat, some even as heavy as the platter upon which they sit, I must be off base. I was given to believe from reading on this subject that the servo action was tuned to the rotational mass of the "platter", which must of course include the mat. As an aside, it is gratifying to know that Nelson Pass is into vintage DD turntables enough to use one at an audio show.

For clarification, when you say that Pass uses an 8kg stainless steel platter, do you mean that he puts an 8kg ss mat on top of an 8.8-lb platter on an SP10 Mk2? (Because 8.8 lbs is the weight of a Mk2 platter, IIRC.) So, here you’re going from probably around 10 lbs total (accounting for the weight of the OEM platter + OEM rubber mat) to a total weight of more than 28 lbs (OEM platter + 19.4-lb ss mat). Is that what you meant, JP? I think at that point what must happen is that rotational inertia takes the place of servo action much of the time.

This has nothing to do with wearing out the bearing, by the way. I am wondering how it affects the servo.

By the way, I have no doubt that metal mats can sound great; I just think that the Boston Audio Mat2 sounded more neutral than any metal mat I have tried, albeit none of them weighed 19 lbs.

And finally, here I am talking about a TT101.  Someone said he tried a heavy metal mat on his TT101 and was not enthused.  Has anyone else got an opinion?  I think Halcro has a copper mat on his TT101. One potential advantage of the copper mat on TT101 is that it would act as a shield to block EMI coming up from the motor.  I made a shield for my L07D out of TI Shield placed under the platter "sheet" (as Kenwood calls the stainless steel mat), and it seemed to remove a coloration that was not noticeable until it was expunged. Lots of L07D owners do something like that. The coreless motor stator and rotor in both the L07D and the TT101 are oriented such that there would be a possible field projected upward toward the platter surface.  Does this make sense, JP?

No - last Wayne posted they use a stainless steel platter that they had made with a BA Mat 2. 

Hi,

I just bough a refurbished Denon DP-80 TT from Japan on Yahoo auctions. The seller is a Denon tech and for JPY 16,000 (about US$150) he will replace all caps, diodes and key transistors and also service the bearings and motors. DP-75 is JPY 14k. So fo Denon DD fans, there is now hope to service and rescue these great direct drive TT.
I am now looking for a plinth. Can PBNAudio make me one? The Denon DP-80 has the saucer shape like the Victor TT-101. In fact the Victors copied the Denon look. I have a copy of the DP-80 mounting template.

Driveman, can make any plinth you'd desire - but you will gain much more from removing the DP80 from its tin pan.

This is what I do with the DP80's

http://pbnaudio.com/audio-components/audio-turntables/groovemaster/groovemaster-vintage-direct/pbn-d...

For the Victor TT101 ill make something similar to what I make for the Technics platform as its much harder removing it from its top plate with all the electronics mounted in the bezel around the circumference - sh should you choose to keep the Denon in its platform  Id recommend something like that, remember that you will need a 12" arm in this scenario - a 10" is too short and will interfere with the 14.5" diameter of the platform.

https://systems.audiogon.com/systems/4909

Good Listening

Peter