Just read the TT description. Most TT manufactures would need to sub contract the multi-axis machining to an outside firm due to the capital cost of said machine. Since TTWs primary business is manufacturing for the aerospace industry, they are uniquely positioned to do all the machining in-house, therefore, reducing both manufacturing and R&D cost.
Now having access to mega-buck machines and having expertise in high precision machining does not guarantee a good sounding table, but TTW must be applauded for their attempt to raise the bar on state of the art tables at a relative affordable cost. Time will tell if they have succeeded.
TTW has come in for more than a little criticism on this forum, mostly from one or two dissatisfied customers. I am not a customer, but I always thought they deserve a little credit for their "all-out" approach, whether I always agree with their design decisions, or not. (Usually not.) The Momentus does indeed look to be very well built. I am just not a fan of rim drive the way they do it. However, in the Momentus they have isolated the copper platter from the driven part of the platter, which should be good.
There has been more than one dissatisfied customer of TTW, mostly based on lack of speed accuracy.
Given all the models, changes, problems, and updates in their short history, the wise consumer should avoid this company cautiously.
From how it looks (I'm not familiar with rim drive, more with idlers), the motor drives directly the platter through a rubber O-ring put on it's shaft. I think it's quite a problematic solution: 1) I'm sure they can machine the rim to a great degree of roundness, but it must be matched by the same on the rubber side. I think EMT idlers is a good example here with their machined rubber surface...and even those have roundness problems; 2) The motor is more intimately coupled to the platter than with an idler, which makes it's more visible with all it's cogging.
Also the shaft looks shortish for the 40kg platter, even though it's super hard. Longer shaft=less wobbling (again EMT930/927 is a good example here)
Is it true that Harry (VPI fame) buys some of his parts from TTW?
Bydlo, You have specifically catalogued all the things that I also do not like about rim drive; I just did not wish to go into gory detail. TTW claims to have addressed at least most of the issues in the Momentus.
Lewm, looking at the rubber on the motor's shaft it does not look like a precisely machined surface, but I may be wrong. I'm also wondering how they engage/disengage the motor?
I would think that with a rim drive o-ring with a durometer of about 60 slightly pressed against an 80lbs platter would cancel out any slight out-of-roundness of the o-ring. But if not, a $25K table should come with a high precision/machined O-ring.
Also, I believe that the table can be easily converted into a thread drive system.
Brf, you can think...when you start to listen&measure it can be adifferent experience. I'd not waste my resources on precisely machined copper plate without a mathing rubber surface...and we haven't touched the motor yet
I also suspect the thread/belt drive and idler/rim drive have a different physical optimum of the motor strength/platter inertia, so I doubt one can have a universal solution here, as they propose.
I would be extremely concerned with resale value, with TTW models constantly changing, obsolescence will occur quickly. TTW pricing structure is questionable as well, determining retail and 'street' price could leave a deep hole in your pocket if things don't work out. Seeing TTW's silly Jelco remodeled 'Eliminator' tonearm also brings me to question what other silliness is occurring. In speaking with Larry at the TAVES hifi show last year I understand he doesn't believe in resonance control, just tolerances and machining. This again has me concerned that his methodology is potentially flawed. Undoubtedly the machining quality is impressive, I am afraid however that it may end there...
FWIW, More than a few tonearms are made by Jelco to be sold under other brand names. I've never owned a Jelco or a Jelco clone, but many speak well of their better efforts. I am not familiar with the tonearm, but why do you say it is "silly".
If you're going to build a tt out of alu, brass, and stainless steel (and probably other metals and alloys), don't close tolerances and high quality machining go a long way toward resonance control?
My issue on the face of it would be only with the drive system.
Your feedback that:
"I would be extremely concerned with resale value, with TTW models constantly changing"
Can be easily said of most turntable manufacturers (EX: VPI,ClearAudio and Linn). Items in our hobby are made in such small quantities, it should not be surprising that models are changed/upgraded often.