Let's make a DIYAUDIO TT

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diyAudio Senior Member
Joined 2002
Hi,

Coupling of the record and the DIY vinyl mat or platter is most excellent, no or few reflections--think of it as a constrained layer platter.

Actually you'd have almost 100% reflections but much more delayed in time so they'd interfere less with the message being read giving a much cleaner sound.

It has nothing much to do with CLD either except that you press the same material together to act as a single mass.
The most notable effect you'll hear is when you do not hard couple the vinyl to the underlying layer (your platter) but just let the disk puck do the coupling.

Going to full acrylic/vinyl platter may or may not be worthwhile depending on how the rest of the construction is talking to it.

Basically you should prevent the platter from being upset by bearing and motor noise and give the LP enough of the same material so that the signal that resurfaces can not interfere with the message being read.

Ciao, ;)
 
Ciao Nanook, ciao Paulo, ciao Fdegrove.

So, in the end, this BIG thread seems awakening... :)

Nanook, shortly, I too thought of some chemical released by the PVC stack, that's why I thought of a sun based melting... and thanks for memo of cutting out the top lp label. Up to now, I washed 5 lps. The f*?=^°# label leaves always some paper on the label area due to the fact that the label seems hot coupled to the vinyl, not simply glued... couldn't yet find a way to remove the residual white material totally.

Paulo, the idea of a one-side record is wonderful! Perhaps it's time I look for some DJ's trash (no offence meant for anybody).

Fdegrove (and all), thanks for feedback! My platter is externally alu (I suspect is filled with something - lead or whatever - which makes it quite heavy). My first experiment with just one lp as a mat gave great results. Actually I use 2 of them (correcting VTA, of course), simply stacked. The bearing used to "bear" a heavvy clamp (no more used), so I guess I have no weight stress.

I've read the 3 Al2O3 ceramic pucks solution. I'm still looking for a solution to source such short devices. My wife's mum uses it for modelling wonderful ceramic landscapes, yet it's hard to work with precision. I seem to remember you cut from something, didn't you?

Many thanks you all once more and have a great week,

Stefano
 
Actually you'd have almost 100% reflections but much more delayed in time so they'd interfere less with the message being read giving a much cleaner sound.

hmmm, depends. If the density of the vinyl used for the platter is less dense then the vinyl of the record, the effect of the reflection is several orders of magnitude down, same for the RTV. The effect of the reflections increase as the change in of the material.(Anyone want to compare a glass plattered Systemdek llX to an arcrylic plattered AudioNote TT1 , all else being equal?).

The constrained layer design relies on the effect of changing the densities to minimize the effects, yes the amplitude is changed but the time is increased , so "smear" is less, at least to my way of undersatnading this. Maybe I'm completely wrong (I can accept that).
 
Hello Pedro

If you want to use the Thorens experience and want a bearing wiht very good performance I can help you .

I repair bearing and optimize all Thorens bearing, the bearing is the most important part for the Start.

Up 1 Kg Platter Weight to 8 Kg can you choose what you need.

Ciao

Joel

PS:Sorry for my poor English I can cannot all explain you Pedro but I try (write me in French).
 
Re: diy tt

fantasia said:

The greatest problem is a motor and speed contoll HAS ANY ONE GOT A CIRCUIT WITH EASILY OBTAINABLE PARTS FOR A PHASE LOCK LOOP
TO SPEED CONTROLL A D.C. MOTOR that would be an incredible assett

Here is an ongoing thread that may help you get started with the motor issue. I have been using this motor/controller with excellent results.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=76634
 
Hello,
I have spent some time reading a lot of this thread, and a lot of the discussion seems to be about the platter bearing.

The main problem is getting a bearing that will give a low-friction motion without detectable rumble, but that is easy to make at home.

The air bearing, unipivot and the tetra bearing have all been suggested as being easy enough to DIY. However, although it has been mentioned in passing, the 'sleeve and ball' bearing does not seem to have had much interest. However, if it is good enough for the Teres, and is better than the Platine Verdier turntable's magnetic bearing (on Dice's 17y-old DIYTT), then it shoud be good enough.

The main problem with this type of bearing is getting the sleeve and the shaft to have a good, close fit, while still rotating freely. The cost of getting something custom made is significant, as the parts must be superfinished (highly polished).

The solution to this problem would seem to be on the Altmann DIY TT link. The use of a valve and guide (in the case of the Altmann from an Harley Davidson) would provide the necessary close fit on the surfaces (although I do not like the way that the valve is fixed to the platter on the Altmann, that needs some work).

The ball bearing (Ruby, ceramic, steel...) and thrust plate (POM, teflon, Brass...) can take a lot of load (Dice quoted a figure for a 10mm Ruby ball somewhere, but I can't find it now :magnify: ), and while the sleeve and shaft look small, I beleive that, provided that the Platter is properly balanced and aligned vertically, the side loads would not be vary large at all.

Take a bottle of coke or water, and stand it, upside down, on it's cap. Try to keep it upright with a finger on the bottom of the bottle. When the bottle tilts, it needs lots of force to keep it upright. When it is vertical, it needs very little force (this is not just because of the flat top of the cap!). This experiment could also be tried with a dumbell with weights on just one end, with the weights at the top.

Therefore, if the platter is vertical, there will be very little side load, and the bearing will cope. If you do not use an inverted bearing, the whole lot can be oiled, improving the bearing's smoothness and reducing friction. If you use a thick platter, the bearing could be mounted inside it in the same way as on the Teres.

Motor: Go to:
Floppy drive motor

The standard 3.5" floppy motor runs at 300rpm, the same speed as most AC syncronous motors.

I am sorry about War and Peace :bored: , but I wanted to get my ideas across.

I'll get off my soapbox now... :soapbox:

James:spin:
 
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