Who's used a periphery ring on their TT?

[richidoo]

No problem, thanks Doug. I thought I was going crazy trying to picture how that all worked!

[tmazz]

Do you mean concave, so the rim of the platter is higher than the center? Then a clamp at the center would tension the whole record with pressure on the rim, similar to a rim clamp. If the platter is convex with a hump in the center, then the outer edges flap loose? Thanks for clarifying

Rich,

I actually think convex was correct in the first place. At least with VPI the center of the platter is higher than the rim. This is accomplished by the addition of a 1 1/4" diameter ribber washer at the spindle. The clamp itself has a 3" footprint and is kind if dished so that the outer circumference is the only part that touches the record and it ends up putting a downward pressure at the rim because where it touches the record the level of the platter of lower than the level of the washer at the spindle causing a downward dishing toward the rim. As you tighten down the cl;amp you can actually watch the LP flatten and lay down tightly on the platter. While I have not looked very carefully at the oracle platter, I know the clamp is a similar design so I assume the principle is the same. This would not work with a flat bottom clamp, but because the VPI clamp only applies pressure at the edges it "bends" the record over the washer, which in turn flattens the outer edges.

[richidoo]

Thanks guys!  I would not be surprised if every TT designer had a different philosophy on how best to grip the record. My Technics relies on that magical force of gravity.

[tmazz]

My Technics relies on that magical force of gravity.

Good thing too, if it didn't you'd have a heck of a time trying to set the tracking force. 

[sleepyguy24]

Morning everybody

Sorry for bringing this thread back to life too but the kickstarter campaign below got me looking through the forum archives and I saw this thread as well.

https://www.kickstarter.com/projects/139447563/technics-1200-series-outer-record-periphery-clamp/description

In the time since this thread was last updated has anyone else used turntable periphery rings on their turntables? If so what are your thoughts on them? I do have some warped records so these outer rings might be helpful. One thing though for me is this TT Weights outer ring will cost just as much as what I paid for my refurbed Technics 1200.

Thanks everyone in advance.

[tmazz]

Dean the problem with kind of significant TT weight, be ti a center clamp or an outer ring is that if they are not used with the proper kind of table they can do more harm than good if you have a table that has a spring type suspension adding weight to the platter can screw up the suspension and cause some undesirable results. Remember that the specs of the springs used in a TT are determined to support the specific weight of the table as designed and delivered from the factory. Changing the load on the springs can do anything from changing the resonant point of the spring system to making the suspension ineffective (or even non-existent if you add enough weight to bottom out the springs.) If you notice which tables have factory supplied rings they are pretty much all mass loaded tables without suspension systems that could be messed up by the additional weight (like the VPI scout and classic series.) And the looser the spring system the problematic the additional  weight would be. (hence I don't ever think I have heard of anyone using weights or rings on a Linn.) I don't know enough about the Technics 1200 series to say what the suspension system  is, but I would be very careful adding a ring to a table that was not designed by the manufacturer to have one.