Protractor for Thorens TD160 HD?

[ppat2]

Have the newer model Thorens td160 HD, with the TP250 arm.

Have setup the cartridge using the paper protractor that comes with the deck, which is not too precise.

I don't know if the downloadable protractors on vinylengine.com work with the HD model deck?

Any idea as to other protractor to try?

The Thorens one on vinylengine lists all the model of decks it works with, and the TD160HD is not listed. I tried the rega 250 protractor and the Thorens from vinylengine, and after getting both grid points setup it does not match with the paper guide that comes with the deck. In fact resulting in the cartridge move forward almost 1/4 inch more so than with the protractor Thorens includes with the deck.

The one that comes with the deck has only the single grid to align to, not 2 grids as the other proctors include. I measured to make sure the lengths on the printouts are jn fact 140 and 200mm as specified.

BTW, the manual for the TD160HD states a 17mm overhang for tp250 arm.

I have the mirror one from turntablebasics.com. Strangely, i can setup to both grids on that using the rega Rb250 protractor, and the Thorens equipped guide even though the cart position is 1/4 inch more forward with the rega guide.

Experimentation has shown the sound to be best with the protractor that comes with the deck.

[walpurgis]

You have to be careful with downloaded protractors. They tend not to print out to the exact size. Most Hi-Fi dealers will stock decent ones.

You could try 'Cool Gales' of Bath. http://www.coolgales.com/us.php

I've dealt with them and they are very helpful.

[Barry]

Hi Paul,

The Thorens TP 250 arm is based on the Rega RB250 arm, but the two may not necessarily be identical. In fact I suspect they are not for the RB250 has an overhang of 15mm, whereas you report the Thorens arm has an overhang of 17mm.

You refer to two lengths of 140mm and 200mm. What are these lengths? For the Rega arm the null points will be at a radius of 57.2mm and 120.4mm.

If you can tell me the effective length of the Thorens arm, I can calculate the null-point radii. Until then, set the arm up using the protractor that came with the turntable; the fact that it sounds best suggests this indeed is the right way.



As walpurgis has correctly pointed out, there can often be small errors of scale (as well as astigmatism) when printing out downloadable protractors.

[ppat2]

Hey Barry. The 140 and 200 numbers are a couple of lengths provided on the protactor printout, to ensure that the printout is in fact to proper scale. So if the lines measure 140 and 200, then the scale is correct for using the protractor. For example, if you scaled the page to "fit" when you printed, the lines won't measure out at 140 and 200 so you know the protractor won't be usable.

Re the effective length. Is there a simple way or some preferred method to get that measurement?

[Barry]

Hey Barry. The 140 and 200 numbers are a couple of lengths provided on the protactor printout, to ensure that the printout is in fact to proper scale. So if the lines measure 140 and 200, then the scale is correct for using the protractor. For example, if you scaled the page to "fit" when you printed, the lines won't measure out at 140 and 200 so you know the protractor won't be usable.

Re the effective length. Is there a simple way or some preferred method to get that measurement?

Ah ! - I see.

Sadly there is no simple way to measure the effective length. Do you have the handbook or user instructions for your Thorens TD160HD? The effective length of the arm may be quoted there.

[NRG]

I've had good success using Conrads protractor generator. It runs on windows and will produce a template of your choice. You need a few things for it to work; a windows system to run it, a printer(!), accurate measurement of the spindle to pivot distance, a headshell that allows you to twist the cartridge and accurate cutting of the spindle hole in the template.

I've used this program to generate custom templates for all my decks using Bearwald alignment, printed out on to glossy photo paper it gives very accurate results.

Third link down:
http://www.conradhoffman.com/chsw.htm

[ppat2]

Hi Barry. The effective length is not in the manual, so I have emailed Thorens to ask. We will see... Paul

[fiddlemaker]

I'd also strongly recommend the Conrad Hoffman protractor.
It's a nice little programme that allows you to rescale to compensate for printer errors. You get a protractor that's customised to your exact requirements for the price of a bit of ink and a sheet of photo paper.
With this, you don't need to know the effective length, just the pivot to spindle distance. Actually, given that the PTSD is fixed, your effective length will vary slightly depending on the alignment you choose.

[worrasf]

FWIW I have found the MINT! tractor (http://mintlp.com/best.htm) to be the best I have used. Not cheap and there is a production delay as it's custom designed for a specific TT/arm combination.

Steve

[rkay5]

The effective length is 222mm like all Rega based arms .

[Barry]

If the effective length is 222m, then for Baerwald alignment, the offset angle is 24.89 degree and the overhang will be 18.76mm. The two null-points on the alignment protractor are 65.998mm and 120.891mm (usually rounded up to 66mm and 120.9mm (or even 121mm)).

[fiddlemaker]

The effective length is 222mm like all Rega based arms .

That's the pivot to spindle distance, not the effective length (which is the PTSD plus the overhang).