What did you make for Christmas?


I made Oso Buco and a new turntable. Well not quite a new turntable. But it sure sounds like that's what I did!

Disassembled it, all the way down to having the bearing apart. Its the Teres bearing which you can see Chris originally used a Delrin thrust plate and stainless ball bearing. http://www.teresaudio.com/project/bearing.jpg Extremely smooth and quiet, but the Delrin would wear so he went to teflon over brass which lasted longer but the teflon wore out even faster than the Delrin. 

My solution after a lot of research was a tungsten carbide thrust plate and silicon carbide ball bearing. These materials are so hard that the wear point even after years of play is a teeny tiny little dot smaller than the period at the end of this sentence. 

This was good but not quite as silent. But the silent solution wasn't silent for long and then was replaced by a low rumble. So a good tradeoff. But a tradeoff nonetheless. Wanted something better and with fO.q tape I finally found it!

With the bearing completely disassembled and clean a small piece of fO.q tape is stuck on the bottom of the thrust plate. This adds vibration control and damping while retaining hard wear performance. Here is some info on the bearing and a view in cross section. http://www.teresaudio.com/manuals/Bearing_Manual.pdf The tape does raise the bearing shaft somewhat and this will reduce the journal surface area a bit but only about a half a mm, but keep this in mind as it does raise the platter requiring VTA adjustment later.

Next a washer of fO.q tape was cut to go around the bearing mount hole. Then a strip of fO.q tape is run around the large BDR bearing fastener nut. Look close at picture #19 the big round piece directly under the center of the plinth is threaded and serves as the nut that fastens the bearing. https://systems.audiogon.com/systems/8367#&gid=1&pid=19 In this way now the bearing and platter are held rigid by the extremely stiff BDR Shelf material, while also being suspended by the layer of vibration killing fO.q tape. 

On the top, picture #13, a hand made carbon fiber washer holds the record up just slightly above the platter. I put another gasket of fO.q tape on top of the washer. Another strip of fO.q tape runs along the perimeter of the record clamp. Tightening the clamp forces the edges down onto the platter, creating a contact area equivalent to a vacuum hold down system. That's no idle boast either. When the clamp is removed after playing the record stays stuck to the platter by atmospheric pressure. No kidding. Freaking impress myself.

Next, cut a piece of fO.q tape to perfectly fit the tone arm head shell. Very time consuming but totally worth it. Because now not only is the headshell vibration damped but the Koetsu is mounted directly onto the tape. All original holes are maintained and so the Synergistic PHT go right back where they were. See images. Although these are before images its very hard to see the tape anyway. These are all very stealthy mods! 

There's room for another fO.q gasket where the tone arm mounts, but I decided to call it for this time as I had something even better in mind for this Christmas- Active Shielding!  

Synergistic Research Active Shielding really is just a wire mesh around the cable with 30 VDC on it. Battery strap is wire mesh. Slid the phono leads inside some battery strap, stuck a resistor and cap in series, connect to a Synergistic wall wart, presto change-o we have Active Shielding!

Not just any old Active Shielding, of course. These wall warts were sent off to Michael Spallone for better caps, diodes, and point to point wiring. Something I could easily do myself but there's like 50 diodes and caps to choose from, Michael has done the hard work of finding the best sounding ones, and doesn't charge much, so support the guy, okay? Fabulous mod by the way, did the Tesla ones for my CTS cables, totally ups their game.

So with Active Shielding added the leads and the arm and everything goes back together. There's a whole bunch more stuff I have in mind but its Christmas I want to play with my new toys and this should be big.

Was it ever! Like a whole new rig! Eyeballed VTA, then dialed in by ear, which by the time that was done wow, what a difference! Active Shielding power supplies and stuff, even cold zero hours, this all was a huge improvement. Piano and guitar on Year of the Cat were like some killer audiophile recording now not the run of the mill sound it was before. Groove noise and the noise floor in general were way lower. Way lower! 

This was by the way all accomplished with a $60 sheet of fO.q tape (less than 10% of it) $30 worth of battery strap, etc, and $60 worth of Michael Spallone. $150, maybe $200 all-in. For improvement on par with about a $10k turntable upgrade. No kidding. This was huge. Images float magnificently. Tchaikovsky White Hot Stampers are a religious experience. Best Christmas in years. Even the Oso Buco, red wine and organic fennel pollen in the gravy, delish!

Merry Christmas! And a Happy New Year!
128x128millercarbon

Showing 2 responses by billwojo

@millerCarbon, you do realize that tungsten carbide is 9.0 on the Mohr hardness scale and silicon carbide is just slightly harder at 9.5 on the Mohr scale? Diamond is at the top with a hardness of 10.0 for reference.
Any engineering data on plain bearings (this is not a roller element bearing) will show that one part of the bearing must be considerably softer than the other part.
Using two almost equally hardness materials with just a tiny point contact will result  in the oil film being dispersed and direct contact will take place. This will result in a slow lapping process that will disperse extremely fine and hard particles in the oil. These particles will wind up in the brass bearing supporting the main shaft and get impregnated in the soft brass housing.
Impregnating either silicon carbide or tungsten carbide particles onto a brass plate makes a very nice lapping tool. Do you see where I'm going with this?
I would immediately dismantle this spindle bearing and clean it as best you can before you start destroying it. Replace the disk with a Delrin or Teflon disk, and be hopeful that no permanent damage has been done.
A turntable thrust bearing at the bottom of the spindle is a very difficult engineering problem. There is insufficient velocity between the two surfaces to maintain a oil film and with a heavy platter the almost infinitesimally small contact area insures a very, very high loading per square inch compounding the problem. That is the reason that self lubricating materials are used in these applications. Under no circumstances should two very hard materials ever be used together in this application.
The original designer switched from the harder Delrin to the softer Teflon probably due to the Teflon having better properties as a self lubricating plastic. Since it wears faster in this demanding application he was wise to use the brass plate to back it up. It will no doubt "talk" to you when the ball reaches it in the form of rumble.
Sorry to burst your bubble but you really out smarted yourself with this modification. Even you admitted that it wasn't long before rumble from wear had you digging into it again.

BillWojo
@millercarbon "My solution after a lot of research was a tungsten carbide thrust plate and silicon carbide ball bearing. These materials are so hard that the wear point even after years of play is a teeny tiny little dot smaller than the period at the end of this sentence. This was good but not quite as silent. But the silent solution wasn't silent for long and then was replaced by a low rumble" Well, if the bearing surfaces were not breaking down you would not have developed the low rumble. That was the sound of the carbide surfaces grinding into each other. At a tiny point contact, and I mean very, very tiny when using a ball on a flat surface that can't deform (either the ball or flat surface) with 24lbs of pressure pushing on it there will be absolutely no oil film. None. You were running metal to metal. If you could see a spot on the plate it confirms that it was doing that. A ball bearing on a flat polished plate has a contact area to small to even measure much less be visible.
People talk about vinyl melting when the stylus passes through the groove. Not sure if I believe that or not but they claim the pressure is something astronomical when computed for the contact area and 1.5 gr stylus pressure. Well, the contact pressure for a small ball with 24 lbs is going to many many orders of magnitude higher.
I'm sorry if you can't understand this, just go ahead and apply magic tape to what ever you want if it makes you feel good. I'm just trying to point out an error and save you grief.

BillWojo