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My almost diy project

New power supply time, the frame 18v Traffo is just too noisy, really noisy, so noisy I can hear it on other side of the room, so I am going to make an external PSU. From 0rangeart's boxes and a talema encapsulated toroidal transformer running at 18v. It means the nice people at Schaefer get a bit more custom, but it's probably better this way.

I am ok with the transformer DIY power supply as it is because it is pretty safe at 18v and easy to hook up and it will make switching on and off the TT an easier task without reaching behind the TT to on/off it. It means some extra metalwork and a replacement backplane some 4 core cable and some 4 pole power plugs and sockets for power but it uses two of 0rangearts boxes unused and metal shim from a failed controller project, so it's swings and roundabouts.

Ought to have all the changes finalised by March 26th :)
 
Question.
Shall I fit a third motor?
There is room for it
I can get a double pulley at the top of the sub platter
I can place it oppositionally to the left right motors
The extra weight of the 65mm platter being made for me might be beneficial
The PSU I am making has 60VA @18v i.e. Plenty of current left over.
I have a mounting system that seems to transmit almost no noise to the heavy aluminium top plate.
 
CliveGrace said:
Question.
Shall I fit a third motor?
Click to expand...


I was going to suggest that a while ago but didn't feel it was safe to question your idea for using two motors and odd numbers of belts ;)
A third motor and using the same number of belts with each motor will help prevent the bearing from wearing on one side. Would you need more than one belt per motor in a three motor set up?
 
Mmm. I thought about that but I am doubtful... A bearing would wear on one side if it were just one motor, which is how most turntables are. The pulleys are very loose on Regas and I doubt the number of bands would have any effect on the deck in the slightest, that seems like "butterfly effect" stuff to me, they are quite slack and not at all tight.


I am more concerned about the weight effect of a 65mm platter on a ceramic ball wearing the sub platter's bearing or the peek bearing shaft... That at needs investigating. I may go back to the same steel ball as before if it is an issue.

But I'll sling another one in just for kicks. see what happens, there is no real science or thought gone into this and it sounds great with all that inherent no-no and face slap things a reet proper turntable designer would do.
 
The two motors on your deck are still pulling the shaft to one side. They need to be at 180 degrees to each other to cancel out. A third motor will even things up.
 
But a single motor will "pull" a bearing spindle to one side so I cannot see how it makes that big a difference if it's already a factor of a preexisting design. I just cannot see it making that big a deal.

I guess it's all moot, I just ordered another motor and Gus is sending me a double pulley I can add and subtract pulleys from the triple when I am feeling exceptionally nerdy.

The equilateral triangle arrangement will at least max out the pulley space on the sub-platter and make use of a space under the hood as that space would annoy me being there unused. See how it goes. I am pretty close to finishing this for good.

This is a TT with two pulleys that are not equally spaced:
http://www.europeanaudioteam.com/en/eat-forte-turntable-000007.html
 
Agree with all you say Clive. I simply answered the question of fitting a third motor and gave you my reason for doing so.
 
Yeah I think it's a good idea, and another motor and dual spindle is on its way and the PSU has the grunt to deliver and the new platter ain't exactly going to be light so why the hay not?

Pon3Dek: PonyDek fuelled by pure pony... Designs are based on other people's preexisting designs using salvaged and aftermarket parts, slung together iteratively over a period of time using trial and error and made in Scotland.

have a Dj-P0n3

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Or just an idler bearing pulley for the 2nd and or 3rd positions.
A longer belt around all 3 would reduce the contact area of the belts on the sub platter.
 
Third motor goes in. I await Gus' double pulley in due course but the motor is in, tensioned and fixed in place. I used up a hole originally drilled for an under light hence the position.


3rd Motor day by c-g., on Flickr

There is a system to "hanging" the motors which I will show on the underside that means they can be adjusted quite accurately to accommodate their different positions on the subplatter.

3rd Motor day by c-g., on Flickr

(The holes in the back are covered up by a backplate as the zebrano wood frame was originally from a music controller rescued but damaged in the fire).

Additionally the nice people at Schaeffer sent me the platform for the arm board

3rd Motor day by c-g., on Flickr

This bolts in from the underside of the top plate and can, if necessary take cylindrical shims (a la orbe) to get the VTA. In this case it's machined to fit exactly.

3rd Motor day by c-g., on Flickr

And here it is in place. It's accurate too.

3rd Motor day by c-g., on Flickr

Next up the big ass platter...
 
Oh and notice the circular cutout on the armboard is rebated 1.25mm to take a 16mm ID stainless steel shaft collar with grub screw, this was the most cost-effective way to get the arm correctly aligned to fit the new custom 65mm platter rather than having a thicker arm-board or getting two bearings and grinding one down, it makes sense to combine with off the shelf parts where possible. especially to save machining costs.

stainless shaft collars are ridiculously cheap. £3 I think from bearingboys.co.uk. The arm base is €45. No brainier.

There is a light smearing of silicone between the collar and the inside of the baseplate mainly to dissuade the galvanic reaction that occurs when steel and aluminium come together but I suppose it will have a sonic impact as well.
 
And here she is

Platter update by c-g., on Flickr

The wonderful guys at Tizo Acryl made me a platter to my spec. 65mm x 305mm with a rebate to match Gus's subplatter and a 200mm diameter (100mm at centre) well on the underside to accommodate pulleys for three motors. The original spindle obviously does not reach to the top but a 50mm x 6mm shaft of marine grade stainless taps in gently and does the job fine. In fact the upper spindle does not contact the lower... It just sits on the ring of the sub platter and shaft collar.

It's missing something...

Ah yes...

Platter update by c-g., on Flickr

Next up I am making a custom PSU but I have done enough today...

Platter update by c-g., on Flickr

Note the slight cad faux pas I made with the back of the armboard, I took it to the top plate edge not subtracted 4mm for the bevel. One of many Persian flaws.

I am loving the carbon fibre armwand for the hadcock,mIt is just a stock 6mm OD 4mm ID woven carbon tube, but it is a direct replacement for the aluminium original and the extruded carbon fibre tube that came with it. This was recommended to me by the guy that makes the counterweights.

Platter update by c-g., on Flickr

Oh one final thing was to strip the frame and give it a good rub down and oiling. It has had a bit of abuse what with all that has been going on so I took some time to give the zebrano a bit of TLC. I suspect a few days of light oiling will get thing nice and shiny for Scalford.
 
Looks good Clive. Love the deep platter. The only thing I don't like is having the arm pillar extended like that. Imo it would be better to have a much thicker arm board and a less extended arm pillar.
 
Muchos extra cost if I do that. Maybe revision 4? Yes shorter = good.
The pillar is at 3/4 extension though and most of the nut covers the base so it'll do for now.

I can, thinking about it put the base on 4 x pillars, lower the arm pillar and tighten the arm between the top plate and arm-board. Need to think it through and do some measurements.
 
Just a thought but does it cost that much to laser cut a 10mm thick ally plate with one big hole and four smaller ones? If you cut half a dozen or so you can stack them as reqd.
 
9.5kg or thereabouts. Enough to be concerned in the long term that the weight + ceramic ball may pose too great a wear on the bearing shaft. Zirconium, Steel or Ruby Sapphire all options. Bearings are cheap (if you avoid the usual sell at sometimes 1000% markup resellers). The bearing shaft/collar/whatever it is called is however PEEK and not brass... In the early days of this build I picked it up for pennies. Still looking into ball options. Not an issue at this stage but could be over time.

EDIT: Afterthought. I do have an interesting idea which is to place a second zirconium (no real need for lube with zirconium) bearing at the top of the subplatter's spindle (under the upper spindle) in addition to the normal base of the bearing shaft, that would be tricky to pull off but given the upper 6mm spindle taps in to the 6mm acrylic hole and is held fast, it would soon settle and reach a sort of upper/lower axle effect. Mulling on that one. It's easy to do and remove. It could just as easily transmit more of the subplatter energy into the record rather than dump it in that flywheel that sits on an embedded o ring. This is the point where things get messy if you don't have a plan and I don't have a plan.
 
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