older vs newer version of the ARxa arm

american simplicity
Post Reply
plexi
senior member
senior member
Posts: 526
Joined: 12 Nov 2014 00:04

older vs newer version of the ARxa arm

Post by plexi » 01 May 2018 03:54

older version




This is a newer version. the center spindle is integral to the main center pivot shaft, is a different chape and is about half the size a the older version...any real difference between these two versions? they both seem to use similar pivot screws and similar delrin insert,,
also as seen in bottom pic, this one side's center hole was started a bit off center and the screww ight be close to touching the outer case in operation. Nothing that can be done t this point though? or is there an easy was yo remove and reinsert a new delrin section? unlikely
Attachments
2018-04-30 19_44_03-2018-04-30 19_42_10-DSCN4262 - Windows Photo Viewer - Windows Photo Viewer.jpg
(177.66 KiB) Downloaded 406 times

plexi
senior member
senior member
Posts: 526
Joined: 12 Nov 2014 00:04

Re: older vs newer version of the ARxa arm

Post by plexi » 01 May 2018 05:17

the reason i'm trying to learn about this arm is because i've come to enjoy its open midrange. it's bass is not the most extended or controlled and highs are possibly a touch unresolved but the mids are sweet and open.....i used to have a stock ARxa with this arm and I recall liking this quality. I always though it was the suspendedd belt drive that was responsible for this characteristic I like, but it seems the arm is as much if not more the reason. I'm using it with a lencol75 and dual 1019 and both have this open sweet midrange quality...how such a simple low budget arm sound so good to me is a mystery but......

can anyone name another type of inexpensive simple arm I might like due to its similarity to this AR ? for reference I also kind of like the simple lencol70 arm with its spring counteweight...I seem to like simple arms for whatever reason. Jus talking about sound here.

derspankster
long player
long player
United States of America
Posts: 1347
Joined: 25 Feb 2013 18:03
Location: Ohio

Re: older vs newer version of the ARxa arm

Post by derspankster » 01 May 2018 14:56

I believe there is a third version with a central spindle with a delrin insert at the top.
Attachments
AR_post.jpg
(254.6 KiB) Downloaded 383 times

plexi
senior member
senior member
Posts: 526
Joined: 12 Nov 2014 00:04

Re: older vs newer version of the ARxa arm

Post by plexi » 03 May 2018 15:10

so, having the choice between these two center pivot sections, i opted for the older cylinderical one with more mass and better centered....put on a technics arm and now need to figure out the new pivot to spindle, and overhand appropriate. any Help would be great, am searching net and getting 215-220mm for a pivot to spindle but not sure what overhang should be and what template to use really like the sound of this arm, very open in the midrange my rega and jelco doesn't do/ the AR is not so deep or clear in bass or as resolved way up top but for the middle (most of the music imo) the AR is fantastic sounding.

snfrosten
long player
long player
Posts: 1035
Joined: 23 Sep 2007 18:39
Location: NJ - USA

Re: older vs newer version of the ARxa arm

Post by snfrosten » 03 May 2018 21:57

Spindle to pivot on the AR XA arm is 211mm center to center, 15mm overhang. Replacing the Delrin pivot sleeve with sapphire bearings would improve the clarity and definition in the top end plus better vertical tracking ability.

plexi
senior member
senior member
Posts: 526
Joined: 12 Nov 2014 00:04

Re: older vs newer version of the ARxa arm

Post by plexi » 09 May 2018 06:35

ok, so it seems the types/variation of the type and size of the arm block center material of AR arm is not significant, so I have another issue.

I have swapped out the stock tube with technics. successful. works great, but am now having to finalize it all.
1 - where to secure the tube (theres about half inch play where I can lock it down),
2nd, I need to choose a spindle to pivot (i'd like to use 222m if possible,) and then
3rd,I need to determine the overhang. Not sure how that is determiend, is it a function of the spindle to pivot? etc

snfrosten wrote:Spindle to pivot on the AR XA arm is 211mm center to center, 15mm overhang. Replacing the Delrin pivot sleeve with sapphire bearings would improve the clarity and definition in the top end plus better vertical tracking ability.

not sure if those figures apply to stock ar arm or the one that is replaced by a technics (as I just did)?

here is a pic of three arms/ from left to right is rather modern AR XB (it does not have the back end bend, the other two have fwiw), and the middle is from an old 2 motor AR XA. The arm on right, in use is technics. I had some liberty (about half inch) as to where I wanted to mount the arm itself in the AR center pivot assembly and looking around the web gives differing ideas as to what a technics arm on AR pivot assembly should be> 212 pivot to spidnle with 15mm overhang seems common.

The arm here is used on an isolated arm pod and on a Lenco and dual. I assume the spindle to pivot is the same regardless of what table it is used on? Still confused about why any certain arm needs to be a certain spindle to pivot. Why can't I just use the common rega/jelco 222m and the same overhang they use?
Which is basically what I am doing, using 222mm with about 15mm overhang. I then just adjust offset by eye/ear//// I then move the armpod around a bit to see what it does to the sound which is interesting, and i do end up liking the 222mm a bit better than what I believe is the concnensus on a technics arm tube on ar arm which should be 210mm. I'ts all confusing, but if I can use the AR arm components, with technics tube - at 222mm spindle to pivot, and whatever overhang is appropriate, that would be great. could anyone validate that usage scenario? disregard the headshell twist, as I have no problem doing that by eye/ear. thanks for any ideas

snfrosten
long player
long player
Posts: 1035
Joined: 23 Sep 2007 18:39
Location: NJ - USA

Re: older vs newer version of the ARxa arm

Post by snfrosten » 09 May 2018 16:05

From the look of the new arm it looks shorter than the AR arm. This would shorten the pivot to spindle distance. To get the proper offset and alignment you need to have the spindle to pivot distant correct, 222mm would be way to long, 10mm+ to far away from the pivot and alignment is impossible. The longer the arm wand the further back you can set the arm and you will have less tracking error, again keeping the overhang 15mm+- from the spindle.

plexi
senior member
senior member
Posts: 526
Joined: 12 Nov 2014 00:04

Re: older vs newer version of the ARxa arm

Post by plexi » 09 May 2018 20:07

actually they seem similar length. I n any case I started a new thread elsewhere since this one was really just about the different variations in ar arm pivot sections. And I really need to learn alot about diy arm setups so it would take up too muh space here...thanks

Post Reply