STP distance. Is it critical ?

I am trying to learn about this since I need to mount a tonearm. Altough the template is good, I suspect I could be off a millimeter or two when done drilling the hole and mounting it.

Reading Doug's post, would it be correct to state that if the headshell slots are at least 2 mm long, then this would compensate for a 1-2mm error in pivot to spindle mounting distance?

This might help:

http://www.audioasylum.com/audio/vinyl/messages/77287.html

You can see in numbers what difference there is.

I think the effective length of the arm will change if it is mounted somewhere other than its designed location. I might be wrong, but it makes sense that the arm would swing through a slightly different arc. The manufacturer's template would not line up quite right.

This might help:
The link did not come through correctly.

Here's another attempt:

http://www.audioasylum.com/audio/vinyl/messages/77287.html

Yes, it is critical. When you want to have the specs from the manufacturer to get the best result of this calculated Arm. Some Arms work also with differences (Loefgren and Baerwald are not the only valid datas), but then you need a different alignment System. Otherwise you will ruin the grooves sooner or later. Analog reproduction is precision.

Dear Smoffat: Everything is almost critical in cartridge/tonearm set up depending what you are looking for.

In a cartridge/tonearm set up you can't change the effective length: the distance from stylus to tonearm pivot center.

All the geometry calculations/equations were made with this effective length parameter with a fixed/permanent value and inner/outer most grooves distances.

Baerwald, Löfgren or Stevenson set up calculations take all those three values to obtain mainly : overhang, offset angle and STP distance.

You can find through the net all these geometry calculators where the only parameter that you need give to the " Calculator " is tonearm effective length to have all the set up parameters.

Even you can choose between DIN or IEC standards or even you can make tyny changes on the inner/outer most distance values.

In all cases you will have all the parameters need it to cartridge/tonearm set up and you can use any one of them with your Phantom and decide which works fine for you or wich one you prefer.

With any of these kind of geometry set up calculations the tonearm can be placed anywhere if you respect the effective length at null points.
Yes 1.0mm-2.0mm makes a difference and not for the better.

As Syntax point out: " Analog reproduction is precision. "

Regards and enjoy the music,
Raul.