Eminent Technology ET-2 Tonearm Owners

Chris.
Quite a few of my customers use after market metal mats. SS and CU.
This adds considerably to the moment of inertia of the platter, but none have had any problems that I am aware of.
My own custom platter is the same weight but a slightly higher moment. Again no problems.

Slaw
I very much look forward to reading about your TT project.
As before I agree totally that things need to be true. If you are controlling the whole process and have access to a good machine shop, this should not be difficult.
My TT and Pre happen to sit on granite surface plates, surplus left overs from our machin shop. They are used, not of their flatness but their energy sinking properties.

If you are going to pod the arm, is it necessary to retain the standard arm/ plinth arrangement? Could you machine the arm pillar and pod as one piece? Some would argue that multiple paths to the plinth (pod) can be problematic. Maybe have the final adjustment of the arm's trueness set by the pods feet? Just a thought.

I have fused my custom arm pillar to the plinth with a solvent that actually melts the surface of the acrylic. The vendors of this stuff claim that the result is a homogenous material as strong as the parent. Thus the pillar and plinth are effectively one. I retained the ability to correct any dimensional errors since the whole plinth could be machined with the arm pillar attached.

I'm sure that your project is going to be a lot of fun and produce brilliant results.

Ct0517 - I have listened at length to several SP10's both MkII and Mk3 both with and without the krebsupgrade. To my ears none of them are particularly transparent. Both the Micro Seiki 5000 ( air bearing ) and Ipad (on BDR cones with Cambridge 840 DAC ) sound more resolving, more fluid in terms of timing and have an openness that eludes the Technics.
Re the mats - I've compared the std, stainless and copper and preferred the copper - a bit more focus and cleaner through the mids. The Mk3 is substantially better than the MkII - less jittery and grainy, but bear in mind the Mk3 platter is considerably heavier and more damped than the MkII. In my view playing around with mats on the MkII merely highlights its shortcomings, and you may be better off with something relatively benign rather than resolving.

Ct0517 - further to my previous post, my experiments with copper mats is that you get more out of them when used in conjunction with a record clamp to ensure tight coupling of the record to the copper.

06-23-13: Richardkrebs
My TT and Pre happen to sit on granite surface plates, surplus left overs from our machin shop. They are used, not of their flatness but their energy sinking properties.

This is not correct. Granite is very very hard and therefore tends to pass energy straight through in both directions, it does not sink energy in of itself. Therefore what the granite sits on becomes important. For example HRS use a polymer to dampen the natural resonance their granite shelves.
Readers should also be aware that granite contains high levels of uranium and can be considered radioactive.
My own experience with granite is a hard edge to the sound in the upper mid lower treble - granite has a definite sonic signature related to it's natural resonance.

Slaw - I assume you've seen the 3D printed VPI arms... any thoughts?

Slaw I have owned the JMW 12 in the past. Here is a pic of my past JMW 12 with a pic from the web of the new VPI 3d tonearm.

http://cgim.audiogon.com/i/vs/i/f/1372035211.jpg

Other than materials they still look really similar to me? The wire placement doesn’t seem to have changed. It was used for antiskate as it would push back. The newer VPI arms have additional antiskate on the new arm. Not sure how this tonearm can be one piece?

what does the point in the cup rest on? I would think some stainless is needed on the inside of the female part.