Silly question: can i mod a 12" tonearm to 16"?

[sameal]

So with redonkulous pricing and a lack of modern amenities, the 16" tonearm market is all slim pickin's.


Anybody mod a 12" out to 16"?

[Greg Reierson]

Sure. Pretty much anything can be modified if you know what to do. It's all about geometry, mass, etc.

Here are a few tools to get you started:

http://www.vinylengine.com/tonearm_alignment_calculator_pro.php

http://www.vinylengine.com/overhang_shift_calculator.php

http://www.vinylengine.com/arc-protractors.shtml

http://conradhoffman.com/chsw.htm (specifically the custom arc template generator)

The worst that can happen is that it won't work. Or it might work great. Either way you'll learn something. Give it a try.

[audiocarver]

I don't mean to open a can of worms here, but I have to ask, why wouldn't a 12" length arm work? They generally can accommodate 16" disks.

Keep in mind that the largest disk available today is 14".

Unless your planning on working with old 16" transcription disks?

[sameal]

How would i get the 12" arm to track appropriately on the 16" platter though? Itd have to mount above the platter and in i would think, which would throw off the tonearm tracking id think.....


I have 1 16" that came with the lathe that im dying to hear, but no i dont really plan on working with 16" discs.


My thoughts were to just extend the tonearm tube. I could get two like tonearms and chop.

[audiocarver]

I'm not sure how to answer you question of getting the 12" to track correctly, as I don't really know what tonearm you have and the cartridge installed.

But, I can say for sure, that my Presto 8N lathe came with a Rek O Kut model 160 and it measures around 11 3/4" from pivot point to tip of stylus and tracks 16" disks just fine, at least at 33. Never tried it at 78 though.

If you want to try making a 16" mounting arm you could try it and see, but if you do, please post your findings here.

[Greg Reierson]

A 12" arm can play a 16" transcription disc with no problem at all. You may want to use the Hoffman calculator linked above to optimize the playback arc for the given disc. Most of the transcription discs I've seen only use the outer bands. Optimizing the arc for those bands would be beneficial and easily doable with a 12" arm.

[sameal]

Welp, i ended up landing a 16" tonearm. I figured im already in deep with the refurb, and mounting the arm to the table, that getting the 16" tonearm would cut out some of the work, and be closer to the standard equipment of the day.

I may reapproach this someday, but for now im going to see how the 16" goes.