Home made tonearm ideas.

[Andre Garcia]

Big Project is to make a tonearm, and the result is not until the stylus hit the record and you can listen if everything worth the time and money. But here are, intending finding outs.
I am thinking to make it as a strain one or unipivot, basically both are the same concept, but machanically different.
Anyway here is the bearing made for the unipivot.
Made from brass and saphired glass.
The spindle is stainlesteel, and work very smooth, so far, the important part is done. Now i will see how design the strain suspension, that IMO is more attractive.
Andre.

 

[Nashou66]

Andre, when placing the pivot point on the tonearm have it level with the record playing surface, like the AR XA tonearm is.

Go to page 19

A new Turntable Arm Design

Athanasios

 

[Andre Garcia]

Very interesting reading!
Thanks for sharing!
Andre.

 

[Andre Garcia]

Here is the string suspension tonearm.
Imo better than the uni-pivot so, i guess this is the way to go.
The first experiment are showing good result so far. The string control the anti skate, the azimuth is adjusted turning the whole tonearm.
VTA lifting the string holder.
So far so good.

 

[kmp14]

More pics! More details!

 

[johnjhazel]

Andre, when placing the pivot point on the tonearm have it level with the record playing surface, like the AR XA tonearm is.

Go to page 19

A new Turntable Arm Design

Athanasios

Thanks for the link to the magazine. This is a bit off track but I love those old audiophile magazines for many reasons. One reason is that you can find out how a component performed before aging and supposition occurred. Case in point: the GE VR 1000 stereo cartridge. On the forums, all that I read was that it is a great cartridge but required 5-7 grams of tracking force. Some old reviews including Consumer Reports indicated great performance and a tracking force of 2.0 grams. That led me on a journey of research, discovery, understanding, and to owning two VR 1000's that can track as light as 1 gram with repaired/rebuilt needles. I love the Empire ad in the issue linked above 'The last cartridge you will ever buy'. LOL.

 

[Andre Garcia]

The magnet located in tje bottom part (temporary) are instead a oild bath. They give a good solution but the silicone oil bath should give more stabilization. I will start with the magnets first. (New set)
Andre.

 

[Andre Garcia]

Here is the tonearm.
Made from brass and two pieces soldered together.
The headshell is not interchangeble made from phenolic cotton dense and light.
The headshell will be made from wood.

 

[Andre Garcia]

Headshell mock up installed and already modified.
The string lengh is important. Too short is too much stress and anti skate will be too much even not applaing any force. Longer, less strees , better anti skate adjustment, rotate applying small amount of force. So i need to modify the string holder for at least half inch toller.

 

[Nashou66]

Andre, wouldn't two round disc magnets work better as the pivot than the half barrel type you have there now?

Athanasios

 

[Andre Garcia]

Andre, wouldn't two round disc magnets work better as the pivot than the half barrel type you have there now?

Athanasios

Yes, all this is a mock up set up. Experimenting and taking notes. Tomorrow i will make the counter weight and stop at the craft store for two magnets. The half barrel tend to self align bothering the antiskate.
Andre.

 

[Andre Garcia]

Hi,
Here is the tonearm base. Made from prensed oak wood made in Germany, same as the plinth. To work on it i used my mechanic lathe, because is stiff.
To adjust the null point you just release the tower screw and rotate the whole assembly, easy and accurated than move the cart on the headshell.
Pretty interesting, a lot to do and concider!

 

[Andre Garcia]

So, here is the last update.
The set screw that hold the body to the tonearm is the one that aligne with the bottom magnet. Strong enought. Two simila magnets was too much force.
The counter weight was foung in a plump bob, 8 oz is enought for two!!
And the magnet is a neodinium one that will be located in the bottom.
So far everything work mechanically fine.
Very sensitive to any touch.



Happy Passover and Easter!
AG.

 

[Andre Garcia]

First arrange to see how its look.
This is not the final location.(obviously)

Sorry but nothing from store shelf to discuss here.
AG.

 

[gusten]

Seems to me the effective mass would be quite high. Don´t know if You have any idea of how much it will be.

 

[Andre Garcia]

Seems to me the effective mass would be quite high. Don´t know if You have any idea of how much it will be.

Yes, is in the range of 17 gr.

Andre.

 

[Andre Garcia]

VTA and Anti skate mechanism done.
Just need to attach the final string.

 

[ripblade]

Very nice work, Andre. I would do the headshell differently but this is your baby. Let us know how it sounds when you're done.

 

[Andre Garcia]

Very nice work, Andre. I would do the headshell differently but this is your baby. Let us know how it sounds when you're done.

Thank you!
I am open to any advice.
the headshell is a mockup for weigh calculation. the final one will be in mahogany wood, no slots and slightly short.
So please let me know what do you have in mind.
Andre.

 

[ripblade]

So please let me know what do you have in mind.
Andre.

Well, since you asked....I'm not a fan of shells in particular as they tend to to be flimsy and resonate easily, colouring the sonics of the cartridge. In your case especially so where the whole shell appears to pivot about a single attachment point at one end. Since the arm pivot you're using is inspired by the Schroeder arm, why not use its cartridge mount as well? This is a stout, fixed platform at the end of the wand upon which a small swiveling plate is used to attach the cartridge and adjust offset angle. Like this:

This will probably increase the effective mass, but the trade-off gained in rigidity should be worth it, IMO. This would also simplify adjustment as the swivel point is much closer to the stylus, making alignment easier to set.