Great effort congartulations. What actually made you do it?
Can't see it was to save any $$$ in the process :-)
Can't see it was to save any $$$ in the process :-)
I'll bite and ask a couple of specific questions:
It looks like the brass cylinders are affixed to the bottom of the platter and they would therefore be the fulfilment of a "metal-loaded acrylic platter". Does it work that way? What kind of bearing do you use? What kind of bearing shaft? Which motor did you choose and why? Speed controller?
Queg, Practical reason: the slightest alteration in the position of the outboard pod with respect to the main body of the turntable will completely screw up tonearm geometry. Theoretical reason; there is something to be said for having the tonearm and turntable in the same closed system, i.e., coupled with respect to outside mechanical and acoustical forces. I tend to favor that school of thought, I don't know a good argument for the opposite approach, but this is not the only time I've seen it (e.g., the Kuzma top-line product cum air bearing tonearm), so there must be one. Not for me though.
...but then do we want to get that critical?
Who cares today about useful ideas?
I know one from a DIY Group who bought a thick piece of wood, drilled a hole in it, bought a bearing and made a Platter from Plastic, got an outboard motor for 250,-- and a belt.
And he had a lot of Fans who congratulated him for this Masterpiece ("Great! you don't need $$$ Designs to listen to a 4$ record..."). Me too, I told him, this is a useful design, when he wants to get rid of it he can burn it and has some warmth in his room...
And we have some who tell everybody to everything: "Happy Listening".
Standard became quite low today.
But seriously, it looks good. A mix from Galibier and Mitchel Gyro.
"the tighter the coupling between the arm and the bearing of the platter, the better."
Completely agree. I firmly believe the bearing/platter and tonearm should vibrate in unison if any vibration occurs at all. I think this is the one area Red Point and Galibier turntables differ in a major way. Admittedly, a separate tonearm pod has a more macho look and more convenient for transport.
What I meant is that Red Point and Galibier are different from each other. Red Point uses a separate armpod and Galibier uses a cantilevered armboard attached to the base. I did not mean both brands are different from the DIY turntable. Sorry for the confusion.
Personally I prefer the Galibier approach.
First of all, I could probably never make anything this nice. Liguy deserves all credit for his craftsmanship. I am only remarking about a design element that is in fact seen also in the commercial marketplace, apparently with Redpoint turntables and also for sure in the largest most expensive Kuzma turntable, where the airbearing tonearm sits on its own discrete and very massive pod. Possibly Simon Yorke turntables are also built like the one shown, but I can never see quite whether the tonearm pod is coupled to the main chassis in photos of Simon Yorke products. For the reasons I cited above, I don't agree with the de-coupled approach. I am not saying it's "wrong".
Simon Yorke turntables do not use separate armpods. It uses a cantilevered armboard attached to the base. The armboard is, I believe, marine grade plywood said to be the best sound for SY tables according to their designer after extensive experimenting. He could've easily machine a separate armpod with fancy alloy material but opted to have tighter coupling between tonearm and bearing. I subscribe to such approach because my friends and I had similar experience and none had good sound when the arm is decoupled from the table base. I would love to be proven wrong because I think having separate armpod is quite convenient in adjusting overhang and maneuvering purpose. The Merill turntable takes such approach to the extreme by machining the armboard and bearing mount as one single piece so, obviously, swapping tonearm is not as easy and armboard/bearing mount need to be custom made for each individual arm. Again, just my own experience...
Hiho, You wrote, "I would love to be proven wrong because I think having separate armpod is quite convenient in adjusting overhang and maneuvering purpose."
But what about when you quite accidentally brush the arm pod and you then need to stop everything whilst you get out the protractor and relive the unpleasant experience of re-aligning the tonearm? And I mean from go, because you may have altered the pivot to spindle distance by a mm, which others tell us can be critical. Pain in the butt. And this is quite apart from any theoretical considerations that favor coupling the tonearm base to the main chassis, if not the bearing per se.
"But what about when you quite accidentally brush the arm pod and you then need to stop everything whilst you get out the protractor and relive the unpleasant experience of re-aligning the tonearm?"
You are right Lewn, I had the exact unpleasant experience before. If I am forced to keep a table with separate armpod, I would find ways to drill a hole or bolt the pod to the platform. I think the Verdier simply bolt the armpod to the same platform the platter and bearing assembly shared so it's almost a hybrid. Cantilevered armboard has its flaw too - diving board effect. Anyway, I think we are on the same page about keeping tonearm and bearing as tightly coupled as possible. The separate armpod thing has better snob appeal. The same thing with thick and heavy platter, I cringe whenever I see platters thicker than 2 inches. Not my cup of tea, that's all.
Back to separate arm pods - from Oolong, ho'.
Firstly, both the arm-pod and the tt has to be 'hard' connected to the surface they stand on - plus it better a as level as it gets.
Now you have the issue with platter and arm-pod standing un-damped on a hard surface --- not so good at all, or?
The hard-connected tt will need to stand on some pretty well functioning damping platform, so does the motor too, and the arm-pod? - Too - and separately damped?! This starts too look pretty tricky now.
I think this separation-scheme is looking for trouble, never mind just getting pushed over or only just moved out of alignment. And nothing said about the motor-pod yet, standing on the same resonating slab as the arm pod?!
"I think this separation-scheme is looking for trouble, never mind just getting pushed over or only just moved out of alignment."
You can always check if the oolong tea is shaking in the cup to check for misalignment.
All jokes aside, I completely agree. Trouble, trouble. But then again, what fun is it if we audiophiles are not trouble makers? :-)
The armboard on the Continuum Criterion turntable uses, I believe, magnetic separation. I wonder how that sounds compare to just rigid coupling...