Dodgy Anti-skate on AT1100??

waveydavey

waveydavey

Active Member
Help Please With Dodgy Anti-skate on AT1100 Tonearm??

Hi all,

have recently received an Audio Technica AT1100 tonearm out of Japan. While setting it up on my tt I noticed from about 2" in from the outer edge of the platter to the spindle the tonearm is pushing toward the outside as if the anti-skate is on. In the area outside this the tonearm floats without moving.

On close inspection I have found the anti-skate spring seems to be taking up at this position, can't actually see the spring but there is a fine wire which i can see tensioning between the anti skate adjust and mounting shaft.

I would appreciate any assistance or remedies you may have.

Cheers, Dave.
 
Last edited:
Register to hide this ad
Anti-skate on AT1100

Hello there,
There is no spring in the anti-skate mechanism on an AT1100.

The nylon thread attaches to the arm pillar and then comes across in front of the pillar and attaches to the lever with the adjustable weight on it. When you set the anti-skate to zero the lever should be horizontal and so the weight does not apply any force to the thread wherever the arm is. At maximum the lever should be vertical and so the rotation of the arm lifts the weight and creates an anti-skating force.

First check that the lever moves, pulled by the thread, when you rotate the arm across the platter. Then set the anti-skate to maximum and verify that the lever does not reach its own maximum position (fully upright) before the arm reaches the centre of the platter.

Your description sounds as if the thread has been shortened (a fairly common bodge to try to fix the arm) and so you reach maximum lever movement part way across - from there on the arm is stretching the thread, resulting in a very large force relative to the anti-skate pulling the arm outwards.

Hope this helps, and let me know what you find.

regards

Angus
 
phonomac said:
Your description sounds as if the thread has been shortened (a fairly common bodge to try to fix the arm) and so you reach maximum lever movement part way across - from there on the arm is stretching the thread, resulting in a very large force relative to the anti-skate pulling the arm outwards.

Hope this helps, and let me know what you find.

regards

Angus
Click to expand...

Hi Angus,

I believe you are correct, the thread has been shortened. the lever does move as described but the thread is reaching it's full tension at the 2" mark i mentioned earlier.

There is a small L-shaped plate below the anti-skate mechanism, it secures a chromed pin that the thread bends around between the pillar and the lever. I have removed the pin which has shortened the distance the thread has to travel.

This has enabled the anti-skate to start just inside the edge of the platter and reach full stretch at the run-out groove position. So although it is short of the centre of the platter it is definitely an improvement.

I can adjust the start and finish position of the anti-skate somewhat by rotating the arm pillar in it's mount. Would you agree the optimum position would be to have the max stretch at the run-out or should I have the bias start at the beginning of the disc? I'm thinking the extra load during the last track adjusted to the latter position would be damaging.

I have also noticed while doing all this, with vtf and anti-skate at zero the arm still moves very slightly towards the armrest as if there is the smallest amount of tension in the thread. Is this normal with this design of bias or is it plainly because the thread is too short?

Thanks for your input, Dave.
 
AT1100 anti-skate

Hello Dave,
I agree with your suggested positioning to give the best compromise you can achieve without actually replacing the nylon thread with a piece of the correct length (do-able, but not easy, and you would need to re-adjust the arm bearings afterwards). Set the arm so that the limit of movement of the anti-skating weight - and so the point where thread tension takes over - is at the run-out groove. Low anti-skate at the outer edge of a disc is less important.

With your test of arm movement with anti-skate and VTF at zero as long as you are doing this at the outer part of the platter then the thread should have no influence. It is more likely that the arm pillar is not exactly vertical. Even with a level turntable the pillar can be slightly canted in the arm base, enough to give the effect you describe.

regards

Angus
 
Hey Angus,

yes it seems to work well. the bias kicks in about 10mm inside the vinyl and the lever increases to the run-out groove.
i made sure the deck was level so there may be a little misalignment with the pillar. i'll just put it down to a small amount of in built anti-skate.
i love the look of this AT arm but think i might trade it on for another, would rather have something i know is 100%.
Cheers again, Dave.
ZHlxXXWl.jpg
 
You must log in or register to reply here.
Back
Top Bottom