Difference between JMW 12.5 and JMW 12.6 tonearm

Can anyone tell me the difference between the 12.5 and 12.6 JMW tonearms?
about .1
about .1
Got it the first time. Does anyone know any real differences between these two arms?
Why not ask the folks at VPI ? Send them an email. They are tops in customer service in my experience.
I have spoken with Harry before. He is great to deal with and is a wealth of information. Their hours that they take calls are limited and I just thought that someone on Audiogon would know the difference between the 2 arms.
I'd like to bring up an issue with regards to what I've observed with a friend's 12.6.He recently moved to this arm(on a new TNT/metal composite platter)after about ten years with the "fabulous" Air Tangent!I have observed,if looking at the arm from straight ahead(as though one was checking azimuth),that there is a constant "tick tocking",or left/right(twisting) movement from the balance of the side weights,which were correctly set,so I was told.I own a Graham unipivot,and this is not evident in that design.I also felt the sonic performance was "TROUNCED" by the Air Tangent,even though he seems to be quite happy with the 12.6's performance,as it has a bit more bass(we are not talking alot more)and he is a bass fanatic!
Funny thing,is that he does not seem to be aware of the loss of instrumental body,and harmonic textures that the Air Tangent had.In SPADES!!Yet,I chalk this up to the "newness" syndrome.He is a very experienced/critical listener and I assume the sonic issue will sort itself out.
I'm willing to bet the performance will be greatly improved,if the "tick tocking" can be solved!
I find it hard to believe that the VPI (which dispels with any damping/bearing fluids)would be designed with this effect.Yet,according to my friend,it is NOT a simple adjustment to the side weights,and requires counterweight and possibly other set-up parameters as well.What gives?I still don't know if he has solved this.Or any of his "mucho experienced" audio gurus.
Any thoughts I could convey to him would be helpful.

So speedy, how does your dissertation relate to the original question or are you rambling again?
I'm a "rambling kind'a guy"!!So?A legit issue,on a related product.Some courteous 'goners may actually be of use,as to this issue.Then you can have your "black and white" issues sorted out!
the main difference is that the 12.6 does not have any damping or need for the fluid and the new drop counterweight. probably the new 12.5's even have that. other than that not much
When does the Nordost internal wiring come into play????? Is it with the .6 upgrade or, is there something beyond?

I just bought a VPI Aries 2 Extended with a JMW 12.5 arm. It has the Nordost Valhalla wiring. I think you can get the Valhalla wiring on any of the JMW arms.
weight is the primary difference. when you remove the counterweights and weigh them, the 12.6 is lighter than the 12.5. you can select either standard copper or Valhalla wiring for either 12.5 or 12.6 arms.

whether you get the 12.5 or 12.6 (or other JMW arms for that matter) be sure to get the new version that has fine VTF adjustment via a screw that is machined/threaded into the back of the arm wand. this allows fine cartridge weight adjustments without offsetting the azymuth. OH YES, FINALLY!

the new support armbase and dogleg set screw/post coupling assembly is better at keeping the cartridge aligned when adjusting the VTA. with the previous version you can see the cartridge/wand move as you tighten VTA adjustment knob when coupling the vertical support bar (in front of the cueing lever) to the plinth.

as to the tick tocking... the 12.6 arms cannot be damped because you must use the 12.6 bearing assembly, which does not allow damping. this will require that you use a good tt stand/base and flat lps or a ring clamp to minimize wobbling about the unipivot. if i recall the 12.6 was designed for lower compliance (or is it lower weight? please check w/ vpi on this) cartridges that do not need dampening. you can use the 12.5 arm wands with the 12.6 bearing assembly. You cannot, however, use the 12.6 on a 12.5 bearing setup.