Oxford Crystal Reference restoration

[peter]

Pics:

Can't get the papers in any furthar than this: The spindle points in the same direction as the bearing marker line. The damping material has come away from the spindle and attached to the top of ther bearing



underneath the clamp. will need to disassemble to clean later



Motor spindle, boltheads showing signs of rust



Ok see where the spindle points, between platter and bearing there is contact at the top on this side...



and on the bottom on the opposite side, fishy?



I'm try to show here how the armboard is not square to the corner of the TT



top surface of bronze platter, starting to score again,



but that gap is *tiny*




taken it off now



Bearing assembly and armboard removed, you can see the heads of the bolts that screw into the sorbo supports underneath, the Bearing assy spikes are supposed to locate in them.




Bearing assembly, pin on left opposite reference mark, signs of scuffing at the rim



trying to show "play" in bearing you have to switch between photos






Underneath



Where the arm is fixed and wired, the cable fixture has come away - careful



Bearing end



The cable is VDH D502 apparently



I need to lie down for a while now..

peter

[Spectral Morn]

Boy you have been busy Peter.

The movement in the bearing from the photos looks to be quite a lot and yet form below it looks like it is mounted square but from above its not + there are signs of damage here and there.

You will need to clean a fair amount before fitting it all back together.

Its amazing though that bolts will rust a tad even when kept in a modern house (assuming you did store it in your house).

Snoopdog can no doubt offer further info on what he sees in the photos but I must say that I don't envy you the task ahead. Though it is imho worth it.

Getting the tone arm block square should be easy assuming all the holes can be lined up to make it square. Looking at it I can't help but think "made on a Friday" which is probably not fair as the two Oxfords, one Cyrstalette and their later black two layer TT were very well made, or at least the ones I saw (at the time) looked very well made.

I would once you get things sorted and assuming you keep the AT (Graham 2.2 is a very nice armby the way) get rid of the VDH 502 wiring if you can as its not up to much imho.

Looks from the photos that the AT has only the one mounting bolt. Is there another locator stud etc below, that is hidden? If you had the AT arm mounting (or dimensions) jig then making an armboard would be easy I think.


Regards D S D L

[YNWaN]

Hmm..very intersting indeed - great photo's guys .

The bearing movement concerns me though. Peter, you mentioned earlier that the bearing could be adjusted - how is this achieved?

[Spectral Morn]

Hmm..very intersting indeed - great photo's guys .

The bearing movement concerns me though. Peter, you mentioned earlier that the bearing could be adjusted - how is this achieved?

You really could not ask for better photos...Its almost as good as being there.

Regards D S D L

[peter]

The flash photography tends to magnify the defects, which is good for our purposes, and I have made no attempt to clean anything.

It is located near to a window (not double glazed), you can also just see how the sunlight has bleached the wood finish at the rear over the years. A useful caution to others, I hope.

I think the Friday effect is right. Even the finest craftsperson has good days and bad days, everyone makes a mistake. This is the cost of making things by hand as opposed to by machine. Things then get worse when you try and fix a mistake instead of either accepting it or binning the thing, and starting from scratch and doing it properly. I think pressure to deliver was pretty high for the Oxford folks during that period.

To fix the armboard squareness propably requires fileing two of the holes into slots, accepting it as a quirk, or getting a new armboard and starting from scratch.

When the turntable is polished and clean it really looks fantastic, the mind then helps it to sound fantastic, for a while at least.

It was designed to stay in one place and not be moved. Give this to an audiophile and he is going to tinker and fiddle and tweak and try it here move it there etc, etc. We audiophiles are never finished. I have to put my hand up and admit that a most of the wear was probably inflicted by me.

Steves excellent info and advice will be a tremendous help, no question.

[Spectral Morn]

At the time the recommendation was to use it on a concrete floor (weight and stability + sounding better). I only had a suspended floor at the time and the idea of wall mounting it on a large target wallshelf + granite shelf put me off (+lack of money) When the wall mount version (which did not look as nice to me) came out I had bought the Oracle Delphi mk4 so I was happy enough and didn't look after getting an Oxford any more until Snoopdog put his up for sale awhile ago then the memories all came flooding back.

Regards D S D L

[peter]

If you look the photo where I mention that gap is *tiny*, you can see the holes (there are three) that have little grubscrews in them that you can adjust that sets the bearing axis and level.

The bearing movment may be ok, not sure. It may be like a unipivot arm where you think it has too much play but actually it is fine.

Thanks for the nice photo comments guys. :blush:

[Spectral Morn]

If you look the photo where I mention that gap is *tiny*, you can see the holes (there are three) that have little grubscrews in them that you can adjust that sets the bearing axis and level.

The bearing movment may be ok, not sure. It may be like a unipivot arm where you think it has too much play but actually it is fine.

Thanks for the nice photo comments guys. :blush:

Because of the amount of weight in the platter I don't think any play is what you would want, as that would translate into a pronounced rocking as it spun. Level and solid would be my though on it as otherwise you would end up with excessive wear on the bearing.

However I am not Jon so only he and his colleague of the time know what was the end goal of each part of their design.


Regards D S D L

[peter]

I have used the TT on both types of floor. The effect is subtle compared to diferences in the actual room acoustics. The room with the suspended floor is much more "dead" acoustically than the "live" concrete room. In the end the LF resonances in the live room mean that the system sounded better in the dead room. It also depends on the music. The turntable has no problem with percussive music but with classical the speed instability and mistracking are just impossible to ignore after a while.

For proper TT performance though the hard floor is right and fortunately that is where it is going.

peter.

[peter]

Because of the amount of weight in the platter I don't think any play is what you would want, as that would translate into a pronounced rocking as it spun. Level and solid would be my though on it as otherwise you would end up with excessive wear on the bearing.

However I am not Jon so only he and his colleague of the time know what was the end goal of each part of their design.


Regards D S D L

When I say "play" I don't mean to imply it is loose and rattling about. It has one natural resting position (probably the wrong one), and the platter weight tends to keep it in that position. However it is not rigid like a tonarm bearing and can move.

I will probably have to take it apart eventually, but I am a little nervous as this is a critical component that up to now I have been careful not to disturb or even invert. I remember the first time Jon assembled it he did it in such a way as to suggest "don't mess with this" and there was an audible sigh from both of them that indicated a critical assembly milestone has been reached and it was plain sailing from there.

Or they could just have been messing with my head I wouldn't put it past them.