Build your own tonearm headshell

[binspaul]

Hi,

Does anyone have the idea to make a tonearm head shell to match the DIY Schroeder Tonearm ?

Regards,
Bins.

[Jeffrey Davison]

I'm making mine using these guys.... just have to get a little creative with their software. They are a little bit expensive tho..

http://www.emachineshop.com

JD

[tinitus]

Why a head shell

Just make the end flat, and mount the pickup
Small piece of alu, or may better brass, across on top
A couple of screws
Nothing special needed

[binspaul]

Hi,

I would like to do it like in the Schroeder reference arm. But, I am not sure on the dimensions.

Regards,
Bins.

[Nanook]

As long as you have the mounting holes for the cartridge spaced at 12.7 mm all should be easy after that. The overall width should be 25.4 mm (an inch) and about 18 mm (about 3/4") long. The plate can be 2 or 3 mm thick. After that, it's easy.

[binspaul]

Hello Stew,

1. What is the ideal material for the plate: Aluminium/Brass/Steel/Others ? (Can we use Acrylic ?)

2. What should be the width and thickness for the head section of the arm ?

3. What is the angle at which the plate is mounted on the arm wand ?

Regards,
Bins.

[Nanook]

1) I think wood or non-ferrous metals are the best choice, acrylic can flex

2) see the attachment for some rough dimensions, but the "plate" can be 1" X 3/4" X 1/8" or so.

3) if a similar "headshell" is adopted the angle is adjustable and usable for arms of essentially any length.

[binspaul]

Hello Stew,

Excellent work. Thanks a lot. I got a head shell diagram from Jelco (Might be helpful for others too)

Best regards,
Bins.

[brianco]

Firstly you need to think about the cartridge which you
a) already own, and
b) the cartridge which you yearn for!

If you intend using low compliance MCs you will need a very stiff head to control the energy produced, whereas if you use a high compliance MM you can get away with a more flimsy affair.

For MC low compliance I would undoubtedly use pure, fine grain, carbon. It is easy to work - even by hand, but DO use a breathing mask. It is certain that carbon dust will not improve your lungs!

For high compliance anything which is rigid will do, but keep it light and skeletal. THis will reduce the mass. Again I would use carbon but in much reduced quantity.

If your arm is to be straight find the cartridge + headshell centre of gravity and ensure that the centreline through the arm-beam and cartridge head assembly intersect at the correct overall length for the arm + overhang to the stylus tip. This will at least decrease the amount of 'yaw' which you will get if you are out of balance in these planes.

Good luck!

Search on Google for "tone arm geometry". You will get results which will answer any questions re off set etc.

[Jeffrey Davison]

the trouble with this headshell is that it is meant for an "S" shaped arm. The "S" gives the cartridge the "offset angle" that is appropriate for it's given arm length (i.e. effective length, pivot to spindle distance, overhang, etc..) according to a formula to decrease or limit tracking error hence percentage of distortion (Baerwald, Lofgren etc...)
The Schroeder arm is a straight arm and once the length is determined, the headshell is "tilted" or rotated to get the correct offset angle.
The Schroeder arm consists of two pieces... the arm hand ( with an integrated headshell, and a "cartridge carrier that has the ability to be rotated to the correct angle, then screwed/locjed/tightened in place.

Have you ever seen or used an alignment gauge? It is used to check for correct geometry, BUT it is calculated from arm data for a specific set of demension for a specific tonearm using a specif alignmewnt formula. If you use a fixed headshell designed for an "S" arm in a straigh arm, you will never have correct cartridge alignment..... just won't work. If you look close at the Schroeder, you'll see an attachement piece between the cartridge and arm tube. On the Scroeder it allows rotation of the cartridge to get correct alignment. The Jelco headshell is fixed and no rotation is possible (except mayby for azimuth i.e. side to side vertical tilt).

The material of the carrier depends on the compliance of the carteidge you wand to use. Do a google search to find and understanding of this or search this forum... lots and lots of info here. If you look at the suspension of the cartrdge like a spring, you'll see that ther are softer springs (higher compliance) and harder springs (lower compliance). a higher complance spring usually requires less mass weight on it to work properly so aluminum would work well, and a lower complance cartridge would need more mass so a brass carrier would work well. Effective mass is not the same as tracking force so don't confuse the two.

It's a good idea to research and understand how an arm works before you start to build one using another design visually copied as if the measurements / distances / angles etc are not correct FOR THE ARM YOU BUILT, your results will be less than satisfactory and you will be greatly disappointed with the sound and all you efforts, time, money, will have been wasted. You need to understand all these 'terms" and understand how they are applied to the design and construction of the tonearm. They are very easy to understand and it's not rocket science or neuro-surgery.

There's a saying.... measure twice, cut once... in this case. understand what your measuring, understand what the measurements are, do this over and over a few times to really "get it" then build the arm. you'll be much happier with the end result.

JD

Originally Posted by binspaul

Hello Stew,

Excellent work. Thanks a lot. I got a head shell diagram from Jelco (Might be helpful for others too)

Best regards,
Bins.