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AR XA Tonearm repair

The damping system had not been removed, so that is gone. The tracking problem seems to have come from the small clear pin that goes through the threads on the spindle. When I took it out, and put the tone arm back on, the tonearm tracked much easier than before. Is it ok to leave this pin out? was it part of the damping system? The tracking is better, but the wobble is still there, and it is definitely not coming from where the spindle screws into the arm.

here is the spindle with the decayed damping system in place

ToneArmSpindle.jpg


and the arm underside

ToneArmUnderside.jpg


and finally, somebody might find this useful

Tone-ArmWireColorDiagram.jpg
 
mccuskerkt said:
The damping system had not been removed, so that is gone. The tracking problem seems to have come from the small clear pin that goes through the threads on the spindle. When I took it out, and put the tone arm back on, the tonearm tracked much easier than before. Is it ok to leave this pin out? was it part of the damping system? The tracking is better, but the wobble is still there, and it is definitely not coming from where the spindle screws into the arm.

here is the spindle with the decayed damping system in place

ToneArmSpindle.jpg


and the arm underside

ToneArmUnderside.jpg


and finally, somebody might find this useful

Tone-ArmWireColorDiagram.jpg
Click to expand...

The wobble is coming from several sources.
The brass barrel is free to chatter about in the steel collar it rides in. The adjusting pivot needles ride in delrin cups. They have to be left loose enough in order to pivot.

What needs to be done (minimum) is fuse the brass barrel to the steel collar.
I use a special damping compound. The next issue is the delrin cups need removed and sapphire "V" jewel cups installed in their place. The adjusting needle screws need to be re-polished to a fine point. ( you would not believe what they look like under a scope of 200-250 mag) The post needs polished, a thrust plate needs installed above the original delrin thrust plate. The adjusting needles need set to 10-20mg of friction.

Other things that can be done to take the arm to pretty high standards is re-wire. Internal damping of the tube. fixing the armtube to the arm boss (the square aluminum housing) at exact length needed to get the alignment you want. AR spindle to pivot is 210mm, AR recommended overhang is 15mm.

All wobble will be gone, and the arm will compete with arms well up the price list.
 
Well, almost a year has passed and I have not fixed the tone-arm, and I missed another record store day because of it. I now have the time to restore the table, but I would rather have an expert do the arm work (looks like some fancy tools might be needed) Does anybody know anybody?
Thanks!
 
I, personally, would get a different arm. I am not going to call it 'ًbetter', since I have no expire fe with the ARXA, but it would probably be easier and more fun.


Ben aka MacKat
 
mccuskerkt said:
Does anybody know anybody?
Thanks!
Click to expand...

Our very own Marc Morin is the guy who can help you. He also makes available some VERY affordable upgrade parts that he has engineered from the original AR parts. The upgrades are very much worth their modest cost.

When everything is in place, as Marc implied in his previous post, the humble AR/XA is capable of some shockingly high-level performance. Marc did some work on my AR/XA and I now love that little table dearly. The front-to-back imaging and PRAT are stunning.

ARXA.jpg
 
Last edited:
mackat said:
I, personally, would get a different arm. I am not going to call it 'ًbetter', since I have no expire fe with the ARXA, but it would probably be easier and more fun.
Click to expand...

I'm not so sure it would be "easier" to replace the arm, since it would involve drilling the steel T-Bar and re-balancing and re-tuning the suspension, which is rather tricky, I would imagine.

The stock arm is capable of much better performance than its somewhat crude appearance indicates.
 
I take it that the arm block is screwed onto the post tightly. If not, that's a source of wobble. And I take it that damping mechanism has been disabled. The only difficult thing with that arm is making sure that the pivot pins actually go into the delrin cups, rather than contacting the metal surroundings, or getting set into the gap beween the delrin and the metal.
It's a very simple arm to work on, and all you need is a small screwdriver -- of course if the wires are broken, it's a bit harder.
 
mccuskerkt said:
Well, almost a year has passed and I have not fixed the tone-arm, and I missed another record store day because of it. I now have the time to restore the table, but I would rather have an expert do the arm work (looks like some fancy tools might be needed) Does anybody know anybody?
Thanks!
Click to expand...

How soon ya want it fixed?

BaMorin@AOL.com
 
mackat said:
I, personally, would get a different arm. I am not going to call it 'ًbetter', since I have no expire fe with the ARXA, but it would probably be easier and more fun.


Ben aka MacKat
Click to expand...

On the XB I'm currently tinkering on I modified the arm tube with a bayonet type mount. The rest of the arm is "stock" except for internal damping, wires, the vertical pivots are sapphire and the thrust pivot plate is mirror finished hardened steel. The Roksan Tabriz arm I had on my ES-1 wished it performed like this arm.
 
mackat said:
I, personally, would get a different arm. I am not going to call it 'ًbetter', since I have no expire fe with the ARXA, but it would probably be easier and more fun.


Ben aka MacKat
Click to expand...

You have no experience with an XA, but you feel like you can recommend what is easier? How does that work?
With a bit of help(if needed), working on an XA arm is quite easy. Changing the arm, not so much.
 
KrisM said:
You have no experience with an XA, but you feel like you can recommend what is easier? How does that work?
With a bit of help(if needed), working on an XA arm is quite easy. Changing the arm, not so much.
Click to expand...

Aw, let's give Ben a pass, he was trying to be helpful.
 
I considered changing the tonearm, and I agree that there are pros to doing that, such as keeping a couple different carts in their own headshells, without paying 50-60 dollars per. In the end, it came to a question of personal philosophy, either replace, or see what can be done with what I already have.
 
Arm is on its way to marcmorin, RCA and AC jacks just arrived in the mail, base and plinth sanded, its gonna be a turntable again soon!
 
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