DIY TT

As for the 12" Arm I referred to it, as there are commonly seen configurations using a arm of this length on a Two Tonearm Plinth Design.

I am not an owner of  12" Arm but do listen to them. I have listened to the SME V/12" on quite a few occasions prior to Coved, there is a Glanz 12" Model I regularly encounter with a Miyajima Cartridge.

Again I have never detected at any time a difference that is perceivable as a separation between a 9" in use and a 12" in use.

The enjoyment factor during the replays is parity for me when both length arms are in use. 

Another friend who extremely analytical as a listener and in their Mechanical / Electronic Engineering approach, is assisting with rethink designs for a known Tonearm Producer and is the assembler and Tuner of the Brands Top of Range Models, along with being the EE, for the Brands next range of Phonostages.      This friend has recently gone to using a 12" version of a rethought out design for the one in use,  and this has now elevated itself,  as the main used Tonearm in my friends system. I am yet to receive a demonstration of this new addition to their system. 

The individuals I regularly speak to, who produce their own versions of Tonearms and are much more technically minded than myself, have not convinced me during my inquiries, a 12" Model will be a significant improvement. I am not convinced these individuals will be offering a option on a 12" design for their creations.

Again others might feel much more support for the design is merited and be more encouraging in the idea of choosing the length as a model. 

 CLD is a heavily debated method and has quite a few methods regularly seen that is not exactly CLD.

If you want to be guided to good CLD Construction advice supported with measurements for the works created, let me know and I will PM information on how to access it.

@holmz : 

 " I’ve been looking at a few 12” arms.."

Even that you have several years in Agon and for your posts as this one seems to me that you are not very aware of what " happens " in the Analog Forum because the 12" issue was analised severakl tiems in several threads. Aniway, a 12" tonearm makes more harm than any real " help " to the cartridge works. Yes, the 12" arms looks really good but the cartridge quality performance normally is better through shorter tonearms than the 12" effective length. As larger the tonearm as slower bearing arm response to the cantilever/stylus tip tracking movements along that the inertia moment is higher and the 12" arm dynamic mass goes against the crtridge job but don't take my word  and read what the tonearms SAT designr says about and I want to tell you that I owned around 8 to 10 12" tonearms:

R.

In the other side and if you decide to go for the DP80 let the double platter in stock way, the main advantage of that double platter is to " kill " resonances. Again Denon knew what they designed.

Now, the best plith is no plinth and you can run the DP 80 in " naked " fashion with tonearms mounted in tower pods.

Btw, which TT/tonearm/cartridges do you own?

R.

Pindac, I asked about your claim that Denon made a gunmetal platter for the DP80, or that there is an aftermarket gunmetal platter for it.  Can you respond to that?

I have no beef with low mass plinths per se, but for a DD turntable, the plinth must anchor the motor so that it does not spin the chassis, or otherwise cause the whole TT to move due to Newton's Third Law of Motion (for every action there is an equal and opposite reaction).  This is especially important if you use an outboard arm pod. You could use a low mass plinth, if you anchor it to a heavy shelf, for example.  But if low mass is your god, then one really ought to look at Rega turntables, which are designed from the ground up to be lossy in terms of energy retention. The notion that you need a low mass plinth so you can move your TT around to various audiophile gatherings is just not a factor for me or most of us. If portability is so important, then get a Rega which you could use just for that purpose.  I've seen Linn LP12s at audio shows, just because of their portability.  But neither would be my choice for home use.