Friday, 11 May 2012

AR-XB FrankenTonearm

Another project, another post.

This AR-Xb turntable came home at the same time as the Empire. It's a simpler thing, and easier to fix up in some ways. It has a lot of similarities in design to the Empire but is is almost like the poor relative of the fancy Empire, from appearance right though to execution. It's almost like both makers were given a basic design, but one of them had 5 times as much money to spend to bring it from blueprint to market.


Both tables are suspended belt drive manual devices and they are completely manual in execution.. Speed is changed by turning the table of and moving a belt from one pulley to another. They have an on/off switch and a cuing lever, the headshells are not interchangeable. The platters are 2 pieces and are fairly heavy.

They also quite quirky and are almost of legendary status for their sound qualities, largely as a result of their simplicity. They also have their fatal flaws.

AR headshell closeup

One of the flaws in the AR design is the tonearm. It is not inherently bad, but it does pose some challenges. One issue is that the headshell is again proprietary and on the one I have here it is problematic. As soon as I touched it it practically fell out of the tonearm, and with a little tug it did fall out!

A little research showed me that the glue that holds these in often does fail. In addition, the simple fact that the plastic AR headshell and it's fixed design without cartridge mounting slots is also not ideal led me to think of how I could improve it. Sometimes I am glad I don't throw things out as I was able to come up with some parts to fix this up. It might take a while to finish the job as I will have to source some wire but I made some good progress tonight.

AR Tonearm graft 1

Some months ago, I took apart the Zenith/Garrard turntable I bought with a Zenith receiver and speakers about a year ago. The speakers have been sold and the receiver is still around, and still one of my favourites, while the turntable is still around in pieces. The base and platter come in handy when I am cleaning a batch of records for example. Anyway the tonearm was still here though largely disassembled.

I had read of changes to the AR tonearm wand to add a more conventional interchangeable headshell collet and/or the full arm wand. Usually Technics was mentioned, probably partly because they are common tables but also because you can order spare parts for them because of their widespread use professionally. They also did not sound ideal because of their length and expense too.

AR Tonearm graft 2

My Zenith one looks like it will work well though and it is essentially free. I had to drill out a couple of rivets to remove the arm wand from the pivot end, and was even able to make what was an S shaped arm into the J shape the AR came with. I might have just used the collet end but the diameters did not match anyway. One reason changing the tube can be problematic is that the AR tonearm and counterweight are fairly lightweight. If you change the weight too much at one end you will have to make changes at the other or you will never be able to balance the arm.

I lucked out. Both the length and the weight of the Zenith arm parts are similar to the AR bits and the arm balances easily. I'll weigh the parts later to get some actual numbers. The Stanton headshell ends up in virtually the same spot as illustrated by the AR arm upside down on top of the new FrankenArm. The project is not done as I will still have to order some wire to redo the arm but it looks like it will work out!

AR Tonearm graft 3

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