I'm an audiophile on a budget, and as such, I'm building a turntable out of parts from a decrepit old r-o-k. the bearings and motor are in good shape though.
I am, however in serious need for a tonearm. my plan is to use a grado green cartridge with it. What should I be looking for on ebay that is of good value. or maybe I should be building one from scratch, if it's something I could handle.
Danke!
I am, however in serious need for a tonearm. my plan is to use a grado green cartridge with it. What should I be looking for on ebay that is of good value. or maybe I should be building one from scratch, if it's something I could handle.
Danke!
How about a stopgap arm?
You can search on this forum for simple unipovit arms that can be built in a few hours and cost as little as a few dollars. Looks and price aside these simple but thoughtfully designed arms can perform very well as builders here will confirm. This will give you a taste of unipovit arms and give you something to enjoy from your own hands while you plan out further projects. Good luck and have fun. Regards Moray James.
You can search on this forum for simple unipovit arms that can be built in a few hours and cost as little as a few dollars. Looks and price aside these simple but thoughtfully designed arms can perform very well as builders here will confirm. This will give you a taste of unipovit arms and give you something to enjoy from your own hands while you plan out further projects. Good luck and have fun. Regards Moray James.
take a look at this thread...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=65305&highlight=DIY+tonearm
http://www.diyaudio.com/forums/showthread.php?s=&threadid=65305&highlight=DIY+tonearm
Nanook to the rescue 
Build my $2.19 tonearm (ok in USD it's $1.50). If I can do it anybody can..
a worn out "practice" arrow from a local Archery range
a 3/16 pipe plug
a piece of wood , or acrylic, or aluminum
an old turntable counter weight, or similar
an old ball point pen
some light machine oil
a small piece of wood
an old wire type mouse or "ear pods", for the wire
epoxy or jb weld
12" inches of bliss
Build my $2.19 tonearm (ok in USD it's $1.50). If I can do it anybody can..
a worn out "practice" arrow from a local Archery range
a 3/16 pipe plug
a piece of wood , or acrylic, or aluminum
an old turntable counter weight, or similar
an old ball point pen
some light machine oil
a small piece of wood
an old wire type mouse or "ear pods", for the wire
epoxy or jb weld
12" inches of bliss
Has anyone here thought of or actually tried to use the magnetic bearing assembly taken from an old utility power consumption meter that you see on the side of every building at the service entrance? In these the Faraday disc motor that spins slowly and drives a clockwork counter mechanizm is floating on two magnetic bearings, one at each end of the shaft.
cool green idea... well greenish....
you're elected. We will need pics of the parts and a photo spread of the demolition of the unit to extract magnets would be nice. Then full design data as well as results of all prototypes up to production unit in setp by step hi rez pics.
Sounds like a very interesting idea perhapss the idea for magnetic antiskate could also ber incorporated? I think the fellow who figured that out is from Italy or Switzerland? Not too sure.
Has anybody built an arm with magnets that repel Vs attract like the Schroder? There are also very powerful magnets inside of old microwave oven magnetrons and sites to show you how to extract them.
What about a magnetic repulsion version of a linear tracking arm with neo magnets to act as a zero friction slide rather than an air bearing? Using oposing pole nested ring magnets?
Always liked the thread suspension of the Well Tempered arm as there is zero need for much if any precission anywhere in the arm it's all dialed in at the pivot point with the thread suspension. Clever. Ran out of fresh ideas probably nothing new at all knowing the expert guys that spend their time here. Have fun regards Moray James.
you're elected. We will need pics of the parts and a photo spread of the demolition of the unit to extract magnets would be nice. Then full design data as well as results of all prototypes up to production unit in setp by step hi rez pics.
Sounds like a very interesting idea perhapss the idea for magnetic antiskate could also ber incorporated? I think the fellow who figured that out is from Italy or Switzerland? Not too sure.
Has anybody built an arm with magnets that repel Vs attract like the Schroder? There are also very powerful magnets inside of old microwave oven magnetrons and sites to show you how to extract them.
What about a magnetic repulsion version of a linear tracking arm with neo magnets to act as a zero friction slide rather than an air bearing? Using oposing pole nested ring magnets?
Always liked the thread suspension of the Well Tempered arm as there is zero need for much if any precission anywhere in the arm it's all dialed in at the pivot point with the thread suspension. Clever. Ran out of fresh ideas probably nothing new at all knowing the expert guys that spend their time here. Have fun regards Moray James.
I don't see any repelling magnets. It looks like a ball bearing hanging from a cylindrical magnet, or a magnetic ball hanging from a bolt, or a magnetic ball hanging from a magnet. At any rate, these magnets are working under attraction, not repulsion. Does look like a rather elegant solution, though. Its aesthetics certainly smack of Schroeder.
max
max
attracting magnets yes...
it does look to be a couple of attracting magnets. There is a chap on the World Design forum (http://www.world-designs.co.uk/forum/index.php) who has made an arm this way. A definate concern here is with the nickel plating on the neo magnets. The nickel plate is very thin and if it were to drack orr chip then your bearing surface is toast. One would also wonder how round the neo ball magnets are I seriously doubr that they are up to the kind of tolerence you would find on a decent quality bearing ball. It is a nice idea and it would seem to work as the German folks have qbviously felt that it was good enought to take to market. A drop of low viscosity ferofluid onthe mating surfaces would certainly provide you with an excellent lubricant and it would not have anywhere to go but stay in the gap. I am sure that this would be better than any ball and race style bearing but probably not as good as a well machined unipovit. Still cheap and very easy to diy so that is good to know.
On an aside I had thought that with a repelling set of magnets you would need to have a very heavy body to hold and weigh down the arm assembly so the two magnets sit very close to one another and resonent bounce would have to be calculated to make sure it did not fall into a range that could be excited by either the cartridger or the suspension. Attraction is probably a lot esasier to work with. Interesting stuff. Regards Moray James.
it does look to be a couple of attracting magnets. There is a chap on the World Design forum (http://www.world-designs.co.uk/forum/index.php) who has made an arm this way. A definate concern here is with the nickel plating on the neo magnets. The nickel plate is very thin and if it were to drack orr chip then your bearing surface is toast. One would also wonder how round the neo ball magnets are I seriously doubr that they are up to the kind of tolerence you would find on a decent quality bearing ball. It is a nice idea and it would seem to work as the German folks have qbviously felt that it was good enought to take to market. A drop of low viscosity ferofluid onthe mating surfaces would certainly provide you with an excellent lubricant and it would not have anywhere to go but stay in the gap. I am sure that this would be better than any ball and race style bearing but probably not as good as a well machined unipovit. Still cheap and very easy to diy so that is good to know.
On an aside I had thought that with a repelling set of magnets you would need to have a very heavy body to hold and weigh down the arm assembly so the two magnets sit very close to one another and resonent bounce would have to be calculated to make sure it did not fall into a range that could be excited by either the cartridger or the suspension. Attraction is probably a lot esasier to work with. Interesting stuff. Regards Moray James.
It does look like a good design, and I agree about the fragility of neodym magnet plating. I think the thing to do would be to use a standard ball bearing to hang off the cylindrical neodym. I imagine a ball magnet, in addition to its chipability, would be rather less perfectly spherical than a ball bearing.
Max
Max
Except the bearing surface in the WD forum cases isn't a bearing surface as there is always an airgap of typically 0.5mm. The whole point of the Schroeder style designs we have been exploring is to break the connection between armwand and arm support structure as much as possible, in this case reducing the support to a thread held in position via the mutual attraction of the magnets...
James
James
point taken & understood..
this design is I guess a magnetic version of a unipovit which is cool too. I suppose that the ball roundness and nickel plate issues could be dealt with by using ball bearings as the two contact points with neo magnets behind them to provide the attraction force. Regards Moray James.
this design is I guess a magnetic version of a unipovit which is cool too. I suppose that the ball roundness and nickel plate issues could be dealt with by using ball bearings as the two contact points with neo magnets behind them to provide the attraction force. Regards Moray James.
That might be interesting - I guess the ball bearings could be locked in position relative to the neo magnets above or below them ...
But my experience with magnetised surfaces bearing on each other is that there is some stiction at the contact point that the Schroeder style avoids... I guess it is a way around the patents though!
James
But my experience with magnetised surfaces bearing on each other is that there is some stiction at the contact point that the Schroeder style avoids... I guess it is a way around the patents though!
James
If you don't sell it or use it in a commercial (which means selling plans or anythinglike that) way, patents are no problem. At least in europe. For the "real" DIY patents are some kind of help because of the big collection of ideas published in patents. If you don't earn any money with the use of the ideas published in patents you are free to use them.
Best regards
Floric
good site to look at...
much in english if you look. Lots of great stuff.
http://www.krishu.de/de/index.php?id=DE
much in english if you look. Lots of great stuff.
http://www.krishu.de/de/index.php?id=DE
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.