SME 3012 mk II set up.

[drSM]

I use a 3012 mkII on a td124.
Arm was serviced a couple yrs ago. Has new bearings and was rewired too.
I got a new Jelco HS30 headshell(heavier than standard) for DL103r, and have heavier brass counterweights to increase overall mass of arm.
Also have the little ebony spacer between cartridge and headshell.

I believe it sounds better already - mainly i think by the use of the HS30
I do need help to optimize set up of the whole thing.
In particular i am uncertain how the L shaped bit that carries the rider weight should be positioned relative to the weight behind the main counterweight.
I suspect it should be correctly adjusted to eliminate torque exerted on the knife edge.
I've searched the forum for set up tips for this arm and have not found what i need.
Would really appreciate help. Is there any reference i can be directed to?
Many thanks and stay indoors n safe.

[drSM]

pic

[Made in 1968]

Never ever know one of those old SME wanting a bearing change. Seen people fit Bronze Knife edge but thats about it, but not cos it needed one.

[Greg2010]

https://sme.co.uk/audio/wp-content/uploads/sites/1/2018/09/MODEL_3009_SERIES_II_IMPROVED_INSTRUCTION_BOOK.pdf

Page 12 will tell you how, that is assuming the brass weights you have are the same as the originals.

[WESTLOWER]

Never ever know one of those old SME wanting a bearing change. Seen people fit Bronze Knife edge but thats about it, but not cos it needed one.

I’ve heard of different bearing tolerances on various SME 3012’s, not sure if they were factory variants or later modifications.

[drSM]

Sorry.
This or these bearings were changed - they were buggered after 50 yrs use.
Knife edge bearings retained.

[drSM]

https://sme.co.uk/audio/wp-content/uploads/sites/1/2018/09/MODEL_3009_SERIES_II_IMPROVED_INSTRUCTION_BOOK.pdf

Page 12 will tell you how, that is assuming the brass weights you have are the same as the originals.

Thanks Greg,
That is useful. The diagram on pg 12 shows the set up of the 'wayrod' for a cartridge that weighs 8 g.
I suspect things may be a bit different for models with detachable headshells as the torque exerted could be very different.
So i think weight of headshell and cartridge become relevant.
Furthermore my brass weights add another variable to the equation.
Would you be able to source the instructions for the Series II nonimproved? Thank you kindly.

[Made in 1968]

Sorry.
This or these bearings were changed - they were buggered after 50 yrs use.
Knife edge bearings retained.

Sorry Greg i dont buy it that they needed changing.

[drSM]

Cheers Greg I think i have what i need fro the SME website

[Pharos]

If the weight you are referring to is the rear brass one, from first principles it seems to me that it is there to counter the effect of the offset headshell's weight - to be raised and lowered until any resultant torque around the arm tube axis is neutralised.

I also think that the bearings which you have shown, and seem to me from having rebuilt a series three a long time ago, are those for the horizontal rotation of the arm pivot, and they are really very unlikely to have worn.

They are about the size of a Hoover Senior brush roller, and they must only do about a millionth of the work, and with much lower rotation and speeds.

[Barry]

The installation instructions for a 'non-improved' SME arm are different to those for the 'improved' version, due to the change in the counterweight decoupler design.

For your arm, this is the way to adjust for lateral transverse balance: http://www.analogue-classics.com/html/3009SeriesIIManual/06.jpg

This will apply regardless of headshell used (unless excessive) or of the counterweight.

[drSM]

Thank you Barry and Dennis.
Perhaps i shouldnt have mentioned the circular bearing - they were replaced a couple of years ago as they were clearly buggered - the temperatures and humidity in the tropics probably the causes of that.

The knife edge was not changed.

I now have a heavier headshell, and that will exert greater torque on the knife edge bearing .
Is there a way to accurately counter the (extra) torque?
The gradations on the wayrod would apply only with fixed headshell (or i suppose standard SME headshell) and use of standard counterweights.

[Barry]

As suggested in the installation instructions, place a long narrow-shafted screwdriver under the arm, just behind the knife edge bearings, to lift the arm up. In doing so the arm will 'rock', that is one knife edge bearing will lift first before the second. When looked at from the front of the arm, if the left hand bearing lifts first then there is too much transversal counterbalance and the wayrod needs to be moved closer to the arm. If the right hand bearing lifts first (which is the usual case), there is too little transverse counterbalance and the wayrod needs to be moved away from the arm. Adjust the position of the wayrod so that both bearings lift at the same time.

If your headshell is very heavy, then it might be that you cannot move the wayrod far enough away from the arm without it becoming detached. In this case you need to add the extra playing weight to the one already on the wayrod so as to increase the transversal torque. Having achieved correct transversal balance, the VTF will then need to be adjusted to correct for the extra force now provided by the extra playing weight - easily done by moving the main counterwight forward on the arm stub.

[drSM]

Got it Barry.
Thank you for that clear instruction.
I think I have done it.
Its a pretty large brass riderweight and achieves the right countertorque with wayrod in a nice position,as rearview pic shows.
Big thanks.

[Barry]

Well done Shahrin. :)