DIY Schroeder "Clone"

[berlinta]

Hello Sella,
Please study the patent(a link has been posted here, check out the archive). It contains enough information to build a clone.

Have fun with your project and a great set of holidays too,

Frank Schröder

[randytsuch]

Does anybody know of a English translated version of the patent? The only link I have seen is for a German version, and although the pictures and diagrams are informative, I think it would help to know what the patent says.

And, cool job on the tonearm.
Mind if I ask how much you ending up spending on it?

Randy

[Capt Zach]

Sorry, I've been abroad for quite some time, and dont have access to my arm or turntable (sigh) right now.

The arm was not expensive. A block of hardwoood, cocobolo or otherwise was not very expensive. Provided you have the proper tools, much of this work can be done by hand carving, although its messy and time consuming, and I ensured final accuracy with power tools.

I had a local machine shop make my parts, one which was sympathetic to my purposes (turns out he was actually an adudiophile himself who had made a turntable before!) Quality of workmanship was not the highest, but the arm is functional, and it proved the concept works. I went through many trials before both my own carved parts and the machined parts worked sympathetically.

I would estimate the overall cost was ~$300 US when everything was done.

My design was considerably simpler than that of the original, and in some ways to a disadvantage. As said, most of the details of the mechanism are availble in the patent. Doing a search here will reveal some technical discussions of the design as well. There's quite a lot of variation as to what parts can be used, and how they interract. This is the fun of our hobby!

[Zen Mod]

Cap Zach
some details about magnets
where ,which,cost... ?

[WT]

Great work Cap Zach

I am also working on the Schroeder "Clone" arm myself.

I have one question about the magnet. Currently, I got 2 magnets with 10mm diameter with 10mm high and I guess it is N35 type. Is it enough? What if I use magnet with different diameter; i.e., 12mm and 10mm. I am asking because I have another donut shape magnet which is 12mm diameter with 3mm high and 3mm hole N48.

[Capt Zach]

RE: Magnets

Here's an excellent discussion on this very topic:

DIY Schroeder Tonearm???

I decided to forgo using donut shaped magnets, attatched with screws. I had my machinist cut me a special aluminum cylinder that normal cyllirical magnets could be they could be press fit into, along with epoxy. This has worked well so far. The disadvantage is that on the original arm, they can be adjusted, whereas on my arm, it must be right the first time. I had to have this piece redone a few times until everything was centered just correctly.

I went with small, 8 x 2mm magnets, and stacked 3 of them to increase the flux strength. Choosing the right size is a tradeoff. I was able to get these from a local electronics store cheaply, so I could buy a lot, and choose the better ones. Bigger wider magnets will be stronger, but are more likely to have surface irregularities. They will provide more damping, which may be good to an extent, but will also require stronger support structure, string, etc which may affect the sound. Mine works well enough, but the original design is close to optimum I imagine. Adjusting the distance between the magnets will vary attractive force and damping as well.

[WT]

Yes, I go through that treat before I have courage to start the project.

I like the idea of stacking magnet together. Do you use any glue or just stack them together.

I change some design so I can adjust the magnet gap and not effect the twist string that do the antisketing.

[JesseG]

Hi Capt. Zack

You're correct, the tonearm wire is simple solid core laquered copper wire I got from an old voice coil. I was going to replace it after I tested the arm with some fine Cardas wire, but the thought never crossed me about it possibly adding a bit of edge to the sound.

I have been a fan of wood tonearms for 25+ years. I currently have a Grace 714 - uses Teak.

About wire: I had a very simmilar experience with solid laquered wire. A friend told me about the benefits of fine-strand hi-pure copper for low level signals. Something about skin effects, etc. Anyway, in a fit of foolish experimentalism, I decided to try some of the finest flexible wire I know - computer mouse wire. Every corded mouse has 4 very fine, very flexible conductors inside the cable. There are so many old corded mice around, they can be had for free. Extract the 4 conductors from inside the cord and you have some of the best tonearm lead I have ever heard. It is quite easy to solder and fine enough to run thru the connecting path of almost any tonearm.

This is one cheap, easy upgrade that I think everyone will find worth the trip to the local compu-junk shop.

Your tonearm is very pretty and I bet it works as well as you say.

Jess Gordon
Alert bay, BC

[analog_sa]

some of the best tonearm lead I have ever heard

This astonishing claim will make a whole lot more sense if you tell us what 'leads' have you heard.