AR XA Tonearm Angles Question

I just brought home a very mint Acoustics research AR XA. It's the U version that can be set to US or Euro voltages.

I never used one before. I think some friends might have had one in their dorms back in the day, but I don't remember. It just looked way cool-retro and was so mint I just had to buy it.

Anyway, based on my unfamiliarity with this TT, I have a question about the tonearm. When playing a record, is the angle of tonearm supposed to look like this: downward angle from front of cart carrier to back, then tonearm angles back up to the end of arm. The cart itself is perfectly level and parallel to the plane of album. When sitting on the arm rest the arm angles upward at the end.

 

Here is pic of arm on rest, showing angle down from tip of cart.

 

Maybe it's the photo angle, but that sure doesn't look like what I remember from mine. Looks in these pictures like the whole headshell is twisted counterclockwise if you were looking at it from the cartridge end. The top of my headshell always looked parallel with the record's playing surface. If yours is not you might be able to correct it back by the pivot with the screw you loosen to correct overhang.

 

Post a pic looking down on the turntable

 

It's a great table. Congrats. Can you raise the arm? That should do it.
My guess is the sound might be a little bass heavy the way it is.

 

Yes that's the photo angle. That is precisely level I leveled head shell with a level on top.

My questions are on tone arm itself. If angle of tone arm front from head shell to back of tonearm has that angle where it goes down from head shell and then at about the J-turn close to where it rests on armrest the angle flattens out, and when playing a record it angles down to J, and then at about J-turn arm angles back up.

 

It's not right, arm should look parallel or level with the record. There's a small set screw on the bottom of the arm boss that holds the arm wand tight, loosen and twist the wand so it's level, hopefully the headshell/cartridge will also be level with the record and not slanted or you will have to correct the azimuth of the headshell/headshell collar.

 

It looks like there is a bend just about at J-curve. Adjusting arm angle won't do anything if there is a bend there.

Here are two more pics with levels showing apparent bend. This is with arm on the armrest.

The cart will actually looks parallel to record when playing but there is sure a bend at around the J-curve on the arm.

 

And this one

 

So to summarize, when you look at arm on armrest the arm from the armrest to the back (to the pivot and tracking weight) angles up slightly in the horizontal, and from armrest to the end of head shell it also angles slightly up, so end of headshell is higher than where arm rests on armrest; there is a slight dip of the arm at about the armrest point. Both ends are higher than the place where arm rests on armrest.

 

Arm and shell should be level and parallel with the platter.

 

First check to see if there are spacers in the headshell. And the plastic collar just behind the headshell is probably rotated. I have a mint AR 77-XB.

 

frost you are most helpful. Arm and shell should be level and parallel with the platter.


Thanks, sfrost!!!! Pic is just what I needed!!!

So, arm and shell should be level and parallel with the platter. On mine it dips at spot it rests on arm rests. Both head shell and end of arm are higher than that point.

I have a bent arm.

 

Phoenix - it is not a head shell issue. It has a dip in it just about where it rests on armrest, so both head shell and end of arm by weight are higher than that point. Note my pics that showed it dipping towards that point from both ends.

 

I think a slight clock-wise rotation of the arm wand would bring the arm and shell into the correct configuration, again just loosen the set screw located on the bottom of the arm boss where the wand is inserted and turn clock wise till the arm is parallel to the platter.

 

i think sfrost is the expert.

 

That worked!!! Thanks sfrost. Now the only other issue seems to be the head shell mounting to tone arm. It doesn't mount securely. The locking collar can't lock it in place the head shell still twists. I guess that is threads stripped on the head shell? Or lack of threads???

 

I think maybe that little plastic collar inside the tone arm that head shell snaps into is the issue: it must rotate thus rotating with head shell. The locking collar can't lock it all down. Does that make sense?

 

I mentioned the collar. You can turn it to be in the proper position. I think maybe you can glue it into the proper position. But let sfrost who I think may be M.M. answer that.

 

Yeah when you insert the cart and twist lock the metal collar, that plastic insert can be twisted by turning the cart. You could turn cart 360 degrees. It's not locked into place at all.

 

You have to buy a replacement headshell. They run about $50. Look at the threads carefully and count them on mint originals for comparison to what you see being offered used. That is an item which I would have liked to have seen reworked and sold as an aftermarket upgrade. It really was a problematic part of the AR table. Not a real fan of the arm in general, but the headshell was a PITA when new, and after 50 years, they just crumble with use.
-Bill

 

Thanks, Bill. I don't see any threads. But when I go on eBay the head shells for sale they don't have threads either. I thought that was odd like what exactly is collar threading onto if no threads. But also seems when I insert headshell into that plastic sleeve it's locking into the sleeve with the two tabs, but if - after I tighten the metal collar - it rotates, that also means the plastic sleeve isn't "permanently" set into tonearm, so twisting the headshell moves the plastic insert because that sleeve isn't affixed well to the tonearm. Should that sleeve be glued in there or ???

 

The collar can rotate and the headshell can have worn or missing tabs as KT88 mentioned. I bought two different models of headshells from sellers on eBay. One has better connectors, the other has more durable plastic tabs that fit into the collar. Best to buy one of each and see which you prefer. In any case, just snug up when installing. Excessive force will easily ruin them.

 

There is a slot in the plastic collar. Tabs on the headshell fit into the slots in the plastic collar(the insert in the tonearm).

 

So are those tabs what is sometimes referred to as "threads". If no threads then how does that aluminum collar screw onto anything?

Here is pic of new item for sale showing the tabs: I don't see any threads.