emt 950, technics sp10 - direct drive sound

@pindac 

I need to check out how this is all done. How do you press the bearing - is it a high pressure fit?

Have you done before and after Sn measurements? I recall having a very good conversation with the late great Max Townshend last year about bearings and he said that people wrongly get fixated with the hardness of bearings - that's why, when signals excite them (as per a record player) they can/do cause high frequency sibilance. As such tungsten carbide and steel balls can/do sound better than ceramic balls.

@alexberger thanks - you are yet another person to say the original phono stage is a bit meh. I have two very good phono stages - as such i think i will get the plug option. No doubt the engineer will say it's heresy but there again EMT themselves make a very high end phono stage.

@lohanimal I can assure you all evaluations reporting on improvements to be had, are subjective only, but in some cases on other Vintage TT Models.

I know individuals who have used a Stethoscope to compare the noise levels between Delrin Bushes and Delrin Thrust Pad, used in place of a Sintered Bronze Bush and Original Thrust Pad.

From discussions with others who have thought through the redesign of the inner of the Spindle Bearing Housing, I have been informed that if an Hydrodynamic Condition is present within the Housing the noise levels produced, will be different to separate, between most materials that are selected. I have even been informed of info' that has shown this from the Heyday of TT Production.   

The goal is to maintain the Hydrodynamic condition, which in many designs is not achievable, hence the Thermoplastics machined to a much-improved tolerance than an off the shelf Metal Bush Part, is an improved interface when Hydrodynamic Conditions are not able to be maintained.

Pindac, can you define “hydrodynamic conditions”, as you use the term? Are you referring to maintenance of a thin layer of lubricant between spindle and bushing or ball? Thanks.

The condition where parts that able to have a Metal/Metal contact is reduced substantially, even avoided, by the inclusion of a lubrication that is able to function as a separator with a film of Oil suspended in the spacing between the Spindle and Sacrificial Parts.

When a Steel Ball is used and is capable of coming into contact with the Spindle it is desirable to have these separated.

As stated previously Scoring has been discovered on a Ball belonging to various Turntable Designs, I know of one on the TTS 8000, and reports belonging to Idler Drives, and I have also seen VAS NY Inc having shown a scribed ball on a TT overhaul he was undertaking. 

My own observations have also seen gold micro dust deposited within the Spindle Housing belong to a Vintage DD TT. The Sintered Bronze Bush was suspected to have been worn, but the dust believed to be present resulting from the Sacrificial Material being removed through abrasion was more than was expected to be found. I know I am not alone in having this condition, but one of the 'not too many' that have investigated the condition of the internals of a Vintage TT Bearing Housing.

Numerous designs of TT have failed to achieve a method that ensures a long-term lubrication is maintained. There are numerous TT's from a particular period that would be a Better TT, if the basic needs of the Bearing Assembly were shown a special care for the servicing.

As Hydrodynamic Lubrication is very difficult to achieve in the long-term a regular servicing is a measure to keep things in good order.

A Metal/Non-Metal interface is seemingly working in the favour of the Bearing when an ideal lubrication condition cannot be maintained, it appears to be the better experience when compared to the older used design.

Hi @pindac 

I certainly need to look at thee mod given that he deck is now over 40 years old and regardless will need to be carefully looked at. 

When Wilkinsons worked on my QL10 i got a new teflon thrust pad and a ceramic ball bearing. I am minded to use the watch bearing oil that I bought from Reson (they made a deck called the rota and i read the watch oil used is very clever stuff as it is designed to not displace and go into very small gaps and maintain a film) 

The TTS 8000 i may have to wait a bit for as i have seen the bill for my EMT restoration and it ain't cheap - that said its a full overhaul of the electrics and the tonearm which in fairness is not an unreasonable price.

I need to ask if pitch control can be added to the deck.

@dover I have the narrowline version. It was from an Austrian radio station so it had Lemo connectors - i am getting those changed to standard XLR unless i can be persuaded that Lemo connectors are brilliant. As it happens it did not have the MC boards - the transformer prices are a bit juicy too but I do want to hear the whole thing optimised. 

As it happened it didn't come with an arm so i had to source one at a time when the 929's weren't being made. Annoyingly the one i sourced was from someone that put horrible wire in it and had mis-adjusted it.

Likewise the TSD15 I bought was when EMT carts were hard to get in the UK - i bought it with a view to getting it re-tipped - but it had been owned by total idiot (less said the better) The cost of a rebuild may be un-economic and as such i may get a new TSD15. That said Benjamin has a Thorens VDH tip TSD15 which may be worth getting. 

I have asked Benjamin if he'd do an interview to put onto my direct drive page which is on a well known social network site, or I may ask Jason Kennedy at 'the ear' if he'd post it there.

The interesting/sad thing with DD's is that the real brains that devised the Japanese superdecks are a very shy breed and I've never corresponded with one of them - it will be sad if such knowledge died/disappeared. Thankfully Benjamin took the reins from his father and as such EMT's the world over can be restored to original.