Anyone "Handy" interested in a DIY Turntable Project?

Anyone interested in a possible DIY turntable project? Fancy a challenge?

I'm looking for a collaborator who is a bit handy to help me with an experimental DIY build. I can supply two sets of:

• Frosted acrylic platter (40mm, 2.7Kg) and spindle
• Inverted bearing with ceramic ball
• Seperate AC motor in a pod
• PSU for motor
• Belt

In return I'd like any potential collaborator to build me a plinth (and a different one for themselves). My requirement is that it should be able to to take two arms and have the potential for different arm geometries (ie. interchangeable armboards), but probably for Rega geometry initially. The other plinth ... I don't mind, just so long as the fit and finish on both is good and that its a looker and works sonically of course .

The payoff is you get to keep one of the resulting TTs. It'd be a good idea if you were in easyish driving distance of Nottingham.

If you are interested PM me.

A nice heavy birch ply sandwich is the obvious thought, but interested in other ideas for materials and designs.

PS. Its a serious proposition, I'm not just kite flying. My woodworking/plasticworking/metalworking skills are non existent, hence the need for a collaborator.

PPS. It could be collaborators - plural - I guess, but dunno how you would sort out who kept the TT.

 

Turntable project

Hi Uncle Ants, I am new to the forum but have been in the process of building a system for sometime. I may be interseted in a collaboration with you on this project. Really depends on how soon you wanted it, I don't have a huge amount of spare time at the moment, however if this is going to be over several months then I think I can help. Please feel free to contact me if you would like some futher info or to discuss the project. I shall post my own system on the forum as soon as I take some pictures, but just as a taster:
Naim cdx, Avi S2000MP, Home build 4 channel PWM amp (LC Audio modules) with active crossover, My design Manger 2 way speaker. Manger unit in hardwood sphere mounted onto bass unit in hardwood cone, sitting on granite disc.
The sound is exceptional, crystal clear with dynamics to die for.
Look forward to hearing from you. I am unsure if you only communicate through the forum, perhaps you could advise me, but you are welcome to have my direct e-mail address.
Regards Granville

 

Hi Granville,

It would be a month or so before we even started so no problem there. Wanted to spend some time chucking about some ideas for construction first anyway.

Those speakers sound interesting - any pics?

PM me. We can do email if you want.

All the best

Tony

 

Hi Uncle,
I am about to resurect my DIY Idler Drive project after a bit of a lay of for some speaker building.
I can probably help in some way, especialy regarding plinth building, and travel to Nottingham to watch the not so mighty Forest.
Some feedback and second opinions would be most usefull to me so if I can be of any use let me know.

Paul.

 

Manger pics

Hi Tony
I have posted some pics of my speakers, hope you like them !

Let me know your thoughts on the plinths

granville

 

Hi Guys,

The more ideas the merrier. I need to get confirmation on the price of one last part over which there is a little confusion (its the bottom half of the inverted bearing) before I can order.

Granville - like the speakers - fit and finish looks top notch. Maybe not quite my kind of thing style wise, but they do look beautifully made.

I was thinking relatively simple would be best. Not thinking sprung suspension or anything. I was thinking about a ply sandwich (or a sandwich of ply and other materials for constrained layer damping - what materials though I'm open to suggestion) but basically a big heavy plinth.

If we wanted some sort of primitive suspension - it did occur to me that sitting the plinth on top of a sub plinth and using Steve's superball suspension between would be cheap and hopefully effective - and reversible if ineffective.

I'll do some sketches this afternoon if I get a chance and post them with some ideas.

 

Excuse the dodgy draftmanship and even dodgier handwriting - I will translate if necessary

I was thinking along these lines:



It did occur to me that if you made the hole under the top left armboard a bit bigger than the motor pod, that if you just wanted to go for the one arm, it might be another place to put the motor pod.

PS. I know its hardly original, but there's only so many configurations y'know and I didn't fancy just a big oblong.

 

Paul,

What thoughts did you have regarding plinth material. I was thinking ply because its easy enough to cut with a jig saw (so long as you use a fine enough blade) and I like that exposed ply look from the side But it occurred to me one could use other materials in the mix - and even retain the look if one cut holes in some of the internal layers.

 

Uncle,

I am going along the constrained layer route. I am also going for a unsuspended deck, possibly with a sub-plinth, along the lines of the gorgeous DPS decks and the Music Hall.

My idea is for a Idler Drive but without the Idler! As with most things it has been done before, in the 50's. The whole motor assembly will be hinged to make contact with the sub platter. I am going the sub platter route to isolate any vibrations from the motor while still employing as direct a drive system as possible for (hopefully) good speed stability.

I am trying to get hold of some lead sheet that is plinth sized at the momment then I can start messing about!

What motor are you using?

Paul.

 

That's exactly the sort of thing I was thinking re suspension as an option. A couple of suitable sized holes or dips in the bottom of the plinth and the top of the sub plinth, so that they line up and a superball in between maybe. The dinks'll stop it rolling, though a big blob of glue might also help.

Its the motor pod and motor pod base off of a Pro-Ject RPM9. As I sell them, I get access to the spare parts bin at trade, which is handy.

PS. What are using for a bearing, platter and sub platter - making them yourself or from something salvaged?

 

I am using salvaged parts at the momment to keep costs down while experimenting....custom made precision engineering is not cheep!
I have a LP12 sub platter and bearing and I am awaiting delivery of a Thorents sub and outer platter that I have just won on epay.

If I get as far as a final version the Mitchell inverted bearing would be a good ready made option.

Motors are being a bit problematic at the moment....I want a high torque item but all the cheapies I have tried upto yet have been to noisy. Hopefully epay will come up trumps tommorow!

Paul.

 

have you though about going for one of the old Lencos and stripping the motor out of that? Bloody heavy platters on those - 10lb or so and an idler drive, so the motor should have torque in spades.

 

Hi Granville,

If you are edging toward volunteering for definite you can design the second deck exactly as you desire For the first one, I was going for the seperate motor pod at 7 o'clock, solely because I need to run two arms - and its quite an attractive looking pod and nice and heavy with its separate weighted stand.



Tell us more about the Ali Wood laminates - sounds interesting. Would that be something like the Panzerstuff that Clearaudio are starting to use for some of there higher end stuff? Do you think such a material would add enough mass in itself? or would we need to put pockets of real heavy stuff into it? I guess it sort of depends how thick the plinth is.

Re compliant layers, were you thinking sheet sorbothane or some such? I wonder how that would work compared to say the sub plinth and superballs option?

Re arm boards I don't really know - seems any of those materials could do the job.

I need to think a bit more about the armboard designs. Initially I'm likely to be running with modded rega RB250 or Roksan Nima (Which is a drop in Rega fit). But I'd want the option to try different arms - the longest liable to be a Haddock 242. The armboards as they stand might be too much of an "interesting" shape to get them easily made if I wanted something of a different length. Mebbe an oblong drop in would be better, or even a sliding oblong drop in ... Hmmm :rds2:

PS. did a bit more scribbling last night:



Problem is that's fairly close to the correct scale and the positions for the arms are about correct for a 222mm spindle to pivot. Longer arms would mean longer wings (or a deeper deck?) and as it is, it would put it about 50cm wide (only 35 or so deep though, so maybe deeper rather than wider). Thoughts?

 

More thoughts

I do recall reading a review their new turntable using this NEW wonder material, I would imagine it is manufactured for cladding or decking, I very much doubt it was developed by, or for them specifically .
The problem we will have is finding a user willing to sell a single sheet, rather than buying a full pallet from the importer or manufacturer. Specialist Panel Products manufacture an exciting range of sheets ( I have not spoken to them directly as of yet )

What sort of finish were you looking for on top of the deck ? Just the Ply or stainless steel, acrylic, what takes your fancy.

I don't know the length of the arms you mention, how much difference is there between them?
I would think that producing an arm board to match the design of the deck will look much better than dropping a rectangular board into it. If we go to the trouble of building a bespoke deck with curves, why spoil it with the easy option.

How do you alter the height of the arms you mention ? Are they both similar and will they cope with using a 40mm thick platter or do we need to inlay the platter into the deck ? I presume that deck height is determined by height of the motor unit.
Using superballs between plinth and sub plinth is a no go with a stand alone motor, the sideways pull of the drive belt will work against the principal of the balls. I don't think you have an option other than having a single plinth. I believe that mass is the answer. Light decks even when on an air filled support must still suffer with air borne vibration. I am sure the only reason most decks are made so light weight is down to cost. If we can have enough mass, we wont have a problem or require expensive supports, frames, tables, shelves, platforms.

What are the dimensions of the bearing and what is it constructed from ?
I think a good option would be to mount the bearing into a steel or brass plate, 10mm or so, this would be fixed into the ply and laminated to more sections, building up the required depth. Making up the required thickness from thinner sheet is easier and cheaper than attempting to work with 50-70mm thick material. Having two plinths mounted together with a layer of sorbothane or similar between them gives you even more isolation from vibration etc, but because of the large surface area it will be unaffected by the pulling effect of the motor.

I think If we go ahead we should experiment with arm board construction to find the best material sound wise, I would imagine it depends on arm type also, so maybe you will need
2 or 3 different types to suit your arms ?

Look forward to your response. granville3

 

Okay lots of questions and options here. I'll have a think and post longer later.

But quickly answering a few.

The platter height is to some extent dictated by the motor pod, but there is a fair bit of leeway. Due to the thickness of the platter there is some room for the belt to ride a bit lower or higher of necessary - and the fact that the pod has a detachable stand, so you could potentially use a different, lower stand or stand the stand in or on a bigger stand. I'll post measurments later.

I have yet to get full details about the bottom half of the bearing, but I think its already mounted in a thickish metal plate with three screw holes - it'll probably need to be sunk into the top plate.

RB250 arms have no VTA adjustment, but there are third party VTA adjusters out there. The Nima uses a collet type of arrangement. You could sink the platter a little but not much without potentially having problems with where the belt runs - sinking it some might looks pretty cool though. I suspect to get arms to the right height we might need to mount them in a raised section of some sort. If you look at the arrangement on Spacedeck or a Gyro for example.

Shortest spindle to pivot I'm interested in is 210mm - for the Spacearm. Spindle to pivot for the Rega and Nima is the standard Rega 222mm. At some point I'd be interested in trying a Hadcock 242 - which is I believe 242mm. That'd be the longest I'd be interested in probably. You could go for a 12inch arm but that would make for too big and bulky a plinth. The Pro-Ject 12c tonearm for example has a spindle to pivot of 292mm - that'd need a big plinth indeed.

Top plate finish - shiny and black was my thought - either a lacquered finish, black acrylic or clear acrylic on top of a black surface (the latter I've seen before and looks very slick). The sides, I'd like to see the materials its constructed from, expecially if its some sort of sandwich.

More later. Got to go and read the Observer now

 

If you are wanting to use differant arms you are probably going to have to use a detachable arm board of some type, if so you could use an extended arm board like this, and although not particularly ellegant (IMO) at least it allows you the option of using longer arms if the fancy takes you.

Paul.

 

Thanks Paul, its certainly a practical option ... I'd agree that its not exactly elegant and aesthetically it mings ... aesthetics are important - maybe not from a sound production point of view, but personally they are important.

Paul - just reread that and I sound terriblly ungrateful for a very good suggestion. My apologies. Did you find a suitable motor in the end btw?

 

Hi Granville, Hi Paul,

Spent some of this afternoon doing a some more sketching - hope I haven't got em too wide - I know that can be a pain. The squares on the paper are 1cm and the plan type drawings are at a scale of 1:2

Ok first off a top view:



The little xs in the circles are notional points for feet underneath (Edit - the back ones may be a bit close together).

The circles top left and right, A, B, C are the mounting holes for arms at 210, 222 and 242mm respectively. Rather than widen the design to take the longer arms, I've deepened it and brought the wings in a bit.

The distance "X", I'll come to a bit later as it refers to a thought I had after I'd drawn it and I haven't time today to do another , but in this design the curved shapes top left and right are the armboards and on a rough calc, measuring an RB250 need to be 1.5cm higher than the rest of the plinth, like a shelf at the back. This sketch without the platter might help:



and this with the platter:



On the difficult question of armboards - they would look something like this:



Have to say though - looks a bit tricky to cut to me, but if you say otherwise Granville, I'll bow to your greater experience. I guess you'd screw em to the plinth with alan key bolts, suitably located. Underneath you would need a bigger hole shaped like a racetrack that would cover all of the mounting distances marked out on the top view but bigger, to make space for the big nuts used to secure the Rega arms underneath - if that makes sense.

Finally a front view and an idea which occurred from drawing it:



Now if you look, you can see where the belt would run when it was on the 33 and 45 spindle. You'll notice its higher than the height at the back of the armboards. Struck me that if you increased the radius of the plinth by just over a cm at the front and front sides and brought the distance "X" in the first view right in close, you could "sink" the platter by just over 1cm, you could have a flat top plate rather than one that was shelved at the back and you still wouldn't snag the belt. It'd be just over 1 cm deeper and a bit fatter at the sides, but with a flat top plate it'd sure look cool. There would be joins where the armboards are mind, but still its a thought.

The height of the plinth could be deepened (and made more massy) if we put the motor pod stand inside another stand, to give it some more height.

Lot there. Thoughts?

 

More thoughts

Hi Tony / Paul
I had come across that turntable before on the web, Fantastic woodworking skills, I would be worried about wood worm though !
I had a quick draw up myself before finding your last post Tony, so design may be moving away from your ideal, however I had several thoughts along the same lines as you. Sinking the platter would look very cool, I personally have problems when decks start to look like wedding cakes.
To avoid having a very wide deck to accomodate 2 arms, the platter could be offset as in the pic, this would mean you would have to have one side for the long arms and one for the shorter.
This does make the deck look possibly not as good, at least in plan view.
View attachment 679
On looking at both designs, have we missed something ? Should the arm when at rest be over part of the plinth for the sake of safety ?
Personally I am not a great lover of acrylic, as it attracts dust and marks very easily, finger prints and scratches, but that is just me, I know others love the stuff. However it is easy to work with.
I dont think we would have a problem depending on what the armboards were made of, making them different thicknesses to suit your arms. Keep the sketches coming, it gives me something to ponder when driving about. granville