A-T Head Shell Screw Specs? [Archive] - The Art of Sound Forum

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GeorgeO

15-07-2010, 03:13

Hi all-
I haven't had any luck finding anything more than the most rudimentary specs (basically weight only) on the AT-LH18 OCC Head Shell. I've read on many posts here that some of you use this head shell to great effect with your DL-103s.

Specifically I'm looking for specs on what size metric screw fits the head shell mounting screw holes. Small metric screws aren't easy to come by here in the states and although I'm going to order the head shell, I'm also making a custom spacer and want obtain the proper screws at the same time to avoid additional delay.

Can anyone provide this info?

Thanks!

kcc123

15-07-2010, 08:30

I think it comes with some different lengths of screws with the headshell, so you will be alright to start with.

Genero

15-07-2010, 17:02

There are 7 pairs of screws in varying lengths. The longest set is 1.5mm.

What material & weight are you using for the spacer? I haven't mounted the 103R to the AT-LH18 yet because I'm trying to find a non-magnetic weight. I was thinking of searching for a local machine shop to make a few.

GeorgeO

16-07-2010, 05:52

Thanks for the info. Do you mean the longest supplied set of screws is 15mm?

This weekend I'm going to fashion a spacer from hardwood - I procured a well-machined 3mm-thick slice of Koa wood that I'll trim down to size. I reckon the spacer will only be around 1.5grams in weight.

I've got the DL-103SA which is a little heavier than 103 or 103R at 9.7 grams. I don't have the AT Head shell yet, so for the test I'm going to try my existing Sumiko head shell at 12grams, start with adding an additional 6grams (using coins and blu-tack ) to get the head shell up to the weight of the AT-18, and then add weight in small bits if needed and see when the cartridge starts to sing.

haven't been able to find info on the optimum total head shell weight range for this cart - so this test will hopefully give me some useful info.

Gdg

16-07-2010, 07:02

George,
first, please, time is come to introduce yourself, your system and your musical tastes, in the Welcome area, or Marco will be soon upset with you :eyebrows:
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I'm not suggesting you to get the AT headshell, since it has fixed holes for the screws, and that is no good for obtaining a fine-tune overhang/offest alignment. I suggest you to stick with the Sumiko and add more mass if you need.
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I have a SL 1210 M5G with the stock tonearm, a DL 103SA and a vintage Nagaoka magnesium headshell (same of Sumiko).

At first Marco suggested me a weight of about 27 gr for the cartridge+headshell assembly, but I wanted to sperimentally verify if that was the correct weight.

I bought the "HI-Fi News Test Record"
http://www.thecartridgeman.com/hfn_test_record.htm
which has some tracks to verify the resulting resonance of the cartridge+tonearm system.

I made myself a very light spacer made of a piece of acrylic. My spacer includes the handle, too.

I used the spare additional spacer/weight coming with Techincs SL 1200 (4 gr), fixing it to the headshell with some double-sided adhesive tape

Last, I got the longer bolts here:
http://cgi.ebay.it/TONEARM-CARTRIDGE-FIXING-KIT-STAINLESS-NUTS-BOLTS-/180523918270?cmd=ViewItem&pt=Turntable_Parts_Accessories&hash=item2a081063be

I used the 20mm bolts

So:
* with the stock Technics headshell the resonance was about 10, but the sound was orribly flat.
* with the Nagoaka headshell only the resonace was about 9, but still the sound was not that good.
* with the Nagaoka+additional 4 gr, for a total weight of about 28 gr, the resonance was "8", and finally I had the sound the DL 103SA promised to deliver.

Than I stopped my test, since is not a good thing going lower than that with the resonance.

Watch out: all above is true for my tonearm, which has, including the headshell 12 gr of mass.
All you have to do, now, is to get the test record above and find yourself the right weight of your cartridge+headshell assembly. Try adding 4gr at time, since in my experience this value lower the resonance of 1 point.
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By saturday I'll (well, I hope to) post the complete report of this experience with some pictures.

HTH

GeorgeO

17-07-2010, 03:17

Gdg

17-07-2010, 19:35

Giovanni-
Thanks so much for the sage advice and details of your procedure and results. It makes sense to try to do this setup as scientifically as possible, so I'm ordering the test record ASAP.

I'm looking forward to your complete report.

And yes, I'm guilty of posting before being welcomed, but taking your advice I've remedied that today, in hopes of forgiveness for my impatience.

Best regards-

:) don't feel too guilty, nobody is dead for that, anyway...
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Right now I'm writing my report (it's very-very long, hope someone will read). By tomorrow will be online.
Have a good day