AT33PTG vital statistic

Peter Stockwell · #1 09-01-09, 03:44 AM

Anyone know the distance from stylus point to the centre of the mounting holes. I'm going to use mine in an SME arm and wanted to get a custom "Best tractor" made for it. Best tractor makes arm specific alignment protractors based on effective arm length. With an SME arm the stylus to arm privot varies with the cartridge mounted in the arm.

larzyh · #2 09-01-09, 03:49 AM

I can't answer your question but what is a "custom tractor"?

I have had my 33PTG mounted in my SME IV (for about 5 minutes) and it played fine without any additions or modifications to the arm.

jaspert · #3 09-01-09, 04:21 AM

This one?

http://www.mintlp.com/best.htm

Peter Stockwell · #4 09-01-09, 04:21 AM

Sorry, I should have said a custom alignement protractor.

Yes a best tractor

larzyh · #5 09-01-09, 04:28 AM

Ah, I see. I have a Wallytractor (looks very similar to the above) for my Ittok but use SME`s own for my IV.

Why do you need the cartridge specification; surely the protractor is made specifically for the arm and not the cartridge?

Edit: OK, I think I understand the problem with the SME application. If the data is in the supplied information with the 33PTG (and nobody beats me to it), I will post tomorrow, when I get home.

Tony L · #6 09-01-09, 04:43 AM

Quote:

Originally Posted by jaspert

This one?

http://www.mintlp.com/best.htm

He certainly doesn't seem to understand how SME arms work, i.e. that the armbase is on a slide!

Tony.

Patrick Dixon · #7 09-01-09, 04:52 AM

I don't understand - if you don't align the cartridge body, surely you can end up with the stylus tracking the 'correct' arc, but the cantilever not perpendicular?

Peter Stockwell · #8 09-01-09, 04:56 AM

Quote:

Originally Posted by Tony L

He certainly doesn't seem to understand how SME arms work, i.e. that the armbase is on a slide!

Tony.

Au contraire, I think he does. I exchanged an email or two with him.

http://mintlp.com/userkh.htm

Maybe I don't understand how an SME arm works?

The SME web site assumes a cartridge mounting hole to stylus point difference of 20mm. More accurately, they give effective arm lengths and then add about 20mm for stylus to pivot distance. But if the base of an SME arm is on a slide, then the relative distance between the arm pivot and the centre spindle is going to vary depending on what cartridge you put in it, no ?

Doesn't that mean the the effective length of the arm will vary with cartridges ?

For the M2-10 the "nominal" pivot to stylus distance is given as 239.40 mm and the distance from the centre of the arm mounting plate to the spindle as 222mm. Isn't the final pivot to distance going to be dependent on the cartridge ?

Patrick Dixon · #9 09-01-09, 05:05 AM

Anyway, according to the AT33PTG leaflet which I have in front of me, the mounting hole to stylus tip dimension is 9mm.

The rest of the leaflet is in Japanese, so don't ask me what any of it says.

Tony L · #10 09-01-09, 05:14 AM

Quote:

Originally Posted by User34

The SME web site assumes a cartridge mounting hole to stylus point difference of 20mm. More accurately, they give effective arm lengths and then add about 20mm for stylus to pivot distance. But if the base of an SME arm is on a slide, then the relative distance between the arm pivot and the centre spindle is going to vary depending on what cartridge you put in it, no ?

Doesn't that mean the the effective length of the arm will vary with cartridges ?

For the M2-10 the "nominal" pivot to stylus distance is given as 239.40 mm and the distance from the centre of the arm mounting plate to the spindle as 222mm. Isn't the final pivot to distance going to be dependent on the cartridge ?

Yes, that sounds right, I just got the impression from reading the SMEV bit on his site that he didn't realise the SME could move it's ass. I'm sure I'm wrong and it's just the site wording.

Are you sure SME think a typical cart is 20mm from mount to tip? That's huge, 3/4 inch! I can't think of a single cart of that length, they are usually 9-12mm or so IME.

Edit: I see the protractor guy thinks 9.5mm. That is what I'd guess at too.

Tony.

Peter Stockwell · #11 09-01-09, 05:26 AM

generally there's the "effective length of the arm" and then there's "overhang", add the two together and you get the effective stylus to pivot length. Looks like it's going to be 9mm if Patrick's information is spot on.

Patrick Dixon · #12 09-01-09, 05:32 AM

It's the leaflet that came with my cartridge, so it's down to AT I'm afraid. I expect I could measure it more accurately with my plastic ruler, but to be honest, I just can't be arsed.

Peter Stockwell · #13 09-01-09, 05:37 AM

Quote:

Originally Posted by Patrick Dixon

I expect I could measure it more accurately with my plastic ruler, but to be honest, I just can't be arsed.

Don't think you could, but don't blame you for not wanting to fiddle with your plastic ruler.

Patrick Dixon · #14 09-01-09, 05:48 AM

OK, my fault for not adding the smiley I guess.

Peter Stockwell · #15 09-01-09, 06:41 AM

Quote:

Originally Posted by Patrick Dixon

OK, my fault for not adding the smiley I guess.

Ooops, Sorry, I meant to say that I didn't believe that with a plastic ruler you'd get any closer to an accurate measure of the stylus to mounting hole centres distance. Afterall, parallax and what have you, I wouldn't have thought that the distance could be "eyeballed" at better than +/- 0.5mm.

And I still don't blame you for keeping your ruler in yer pocket