Null Points (or Point) for Sme 3012... ?

[J.D.]

Hello,

Can't really seem to find an SME number for what the null point or points should be for an Sme 3012 series I.

The databases both here and elsewhere offer 'calculated' nulls based on other numbers, from various sources, and generally aren't too reliable.
(Mtg distance, for examp, is incorrect in the VE database for 3012/I)*.
Looking for what Sme would have stated originally.

Though this tonearm is very old by any standard, does anyone have an Sme "Alignment Protractor" (brochure in VE library mentions same as std equip with arm)-- or any other Sme source that happens to mention the Null point(s) in mm, for the series I 3012, by any chance ?

Thanks very much for responses,

J.D.

* The VE database puts 3012/I mounting distance @ 308.8mm whereas the Sme brochure in the 'library' section puts it at 11.58 inches, or 294.13mm.
Having now tried both, I'll second the Sme figure.

[Brian C.]

JD, I used a turntablebasics mirrorback for my Series I/SPU Mono combo

http://www.turntablebasics.com/

Brian.

[JaS]

The VE database puts 3012/I mounting distance @ 308.8mm whereas the Sme brochure in the 'library' section puts it at 11.58 inches, or 294.13mm.

Thanks for spotting that; I'll double check it against the other sources I have for the mkI and update as necessary. I'm afraid I shared my database with the cartridgedb so the specs there are wrong too

Regards,
JaS

PS FWIW early SME arms seem to be optimised for Stevenson alignment and later arms Baerwald.

[kelvin fong]

Hello
I have just started to install an SME 3012 S2. I noted a lot of different figures on effective length, overhang and nullpoints etc.

Fisrt question I have: what is the distance between stylus and tonearm mount in the measurement of Effective length? An SPU G measures 52mm. A Denon 103R mounted in SME head shell measures 48mm. An Ortofon OM MM cartridge in SME head shell measures 50mm.

What is the offset angle, and again based on what distance of stylus to tonearm mount?

I fitted the SME head shell with OM cartridge inverted so that stylus pointed up. I assume the centre of the tonearm pillar axis to be some where at the centre of the apex above the bearing yoke. I measured an effective length of 313mm. I know this is not perfect, for example the apex and tip of stylus may not be parallel to the arm wand. But the measured effective length is more than any figure I have seen in the net.

Grateful for enlightenment by other learned members of this forum.

Kelvin

[johngordon]

The actual effective length isn't really an issue, as the SME arms have an adjustable base. So with the various variations in effective length using SPU types or others in a fixed headshell, the base is adjusted to alter the mounting distance to that appropriate for the manufacturer's alignment which will then be governed by the headshell offset angle. Usually there is enough play between the mounting screws and the headshell holes to enable either Stevenson or Lofgren A/Baerwald. Therefore any two point protractor of that type can be used.

For more on SME geometry see
http://odysseytonearms.blogspot.com.es/ ... metry.html

John

[kelvin fong]

Hi John.

Thank you. Very informative article.

Regards
Kelvin