| mgreene |
With all the recent talk about unipivots and such, has no one ever considered knocking off a magnet stabilized string pivot like the Schroeder? I have been considering a DIY arm just to add a mono cartridge to my TT. This implementation "looks" fairly simple :scratch: Assuming you have a source of wood and carbon fibre, the only things slightly out of the ordinary are the neodium magnets, which are fairly ubiquitous on the web.
See pics and a review of the Schroeder's stuff at his website: http://www.schroeder-tonarme.de/
Mike |
|
|
| Brett |
| quote: | Originally posted by mgreene
With all the recent talk about unipivots and such, has no one ever considered knocking off a magnet stabilized string pivot like the Schroeder? I have been considering a DIY arm just to add a mono cartridge to my TT. This implementation "looks" fairly simple :scratch: Assuming you have a source of wood and carbon fibre, the only things slightly out of the ordinary are the neodium magnets, which are fairly ubiquitous on the web. |
I've thought about this too. It does look straightforward, and I have a spare tonearm mount on one of my TT's....
I'd try a carbonfibre arrowshaft as the tube.
I have a couple of other projects to finish first, but I'm very interested in doing a 12" version. |
|
|
| CV |
Hi fellas,
It might *look* straightforward, but if you read the hifi+ interview with him (it may be available on his website), you'll see it's not quite simple; takes hours + hours to drill the tiny hole through the Nd magnet for instance. I wonder if drilling un- or demagnetised Nd and then charging the magnet would be easier.
Anyway, makes very interesting reading.
cheers |
|
|
| mgreene |
Brett, CV,
I went to the archery store this weekend. A nice, good sized, carbon fiber shaft costs a wopping $5.
As to drilling the magnet, etc., - the interview is not on line where I can find it. CV - can you give us the technical gist of the interview?
Had a few more thoughts over the weekend. Might be possible to simplify construction and get a better result using misc parts such as various aftermarket upgrade parts (arm weights and VTA devices) for Rega and other arms.
Regards
Mike |
|
|
| fdegrove |
Hi,
You guys think it's simple?
No way.:bawling:
Keeping magnets in place around a pivot is not simple at all.
Moreover, all the energy from the catridge has to be drained by the shaft, you see it ain't all that simple since there is no other way to drain of spurious energy.
Not that I want to discourage anyone of course,;) |
|
|
| CV |
Hi
...the interview in hifi+...
The Nd magnet is an extremely hard material; trying to drill a tiny hole in it and get rid of the swarf material (which is strongly attracted back to the block) is a nightmare. Took him about 8 hours to go a few mm IIRC...
Will try and dig out the magazine and see exactly what he had to say.
Why not try drilling a tiny hole in a cheap ferrite magnet and see how you get on with that?
cheers
cv |
|
|
| fdegrove |
Hi,
CV,
No need to dig it up.
There's a scan of the article on Frank Schroeder's tonearm on his website.
See the link in the first post.
Thought I'd save you the trouble,;) |
|
|
| mgreene |
Thanks CV. Something comes to mind - Schroeder is building with long term quality control in mind - I may be able to epoxy - if it eventually comes loose w/o destroying the cartridge it won't be a big deal.
Frank - Schroeder's interview is not included in the material on his website.
Mike |
|
|
| mgreene |
So Frank,
What's the secret? It hadn't occured to me that the magnets could be unstable in this configuration - only a few thousandths apart.
Mike |
|
|
| fdegrove |
Hi Mike,
The problem as I see it is that the N/S relationship of two magnets is easlily disturbed when one is moved and the other held stable.
Surely you recall the force it takes to keep them in repelling position when held by hand?
This is a problem another German designer (it may even have been the same designer, I can't recall) faced with a similar offering about 15 years ago.
I really haven't got a clue how this one works, admittedly I only took a quick look at the pix on his site.
It seems to work well enough but untill I fully understand the design I'd better zip it.:rolleyes:
Cheers,;) |
|
|
| mgreene |
Ummm...
The magnets are attracting eachother in the Schroeder - or I'm far dumber than I thought I was :)
My understanding is that the pivot is the "string" that the arm is hanging on and the mobile magnet (in the arm) attracting the stationary magnet (on the base) keeps the pivot stable.
Mike |
|
|
| fdegrove |
Hi Mike,
As I said, I didn't really look into the design.
Only problem I see is the drainage of vibrations emanating from the cartridge which is probably why the designer uses all kinds of woods.
The attracting magnets are an interesting idea though, I guess I'll have to to my homework on this. ;) |
|
|
| Paul Ebert |
| quote: | Originally posted by fdegrove
Only problem I see is the drainage of vibrations emanating from the cartridge which is probably why the designer uses all kinds of woods.
|
I thought about this (a Schroeder clone) prior to settling on my air bearing arm. Wouldn't the vibrations simply drain via the magnetic field (i.e. heat)?
One thought that occurred to me was using rare earth magnets to stabilize a unipivot. But, that's another thing all together.
Anyway, similarly to the Ladegaard air-bearing design, this approach has the benefit of quite low cost. You don't have to commit a lot of funds to experiment.
Someday, I may give it a try.
Paul Ebert |
|
|
| mgreene |
Why can't the built up vibrations escape via the pivot string to the arm pillar?
I agree that it looks cheap to try. I've started to line up some parts.
Mike |
|
|
| fdegrove |
Hi,
| quote: | | Why can't the built up vibrations escape via the pivot string to the arm pillar? |
That's about the only path there is that would provide a little drainage.
Paul,
The magnetic field won't couple vibrational energy throgh the air.
With an airbearing the pressure field of the air provides a coupling path.
I used to know all the theory behind all that stuff but it's getting rustier by the day.:bawling:
| quote: | | I agree that it looks cheap to try. I've started to line up some parts. |
Good on you Mike.
Keep us posted please.
Cheers,;) |
|
|
| Paul Ebert |
| quote: | Originally posted by fdegrove
The magnetic field won't couple vibrational energy throgh the air.
I used to know all the theory behind all that stuff but it's getting rustier by the day.:bawling:
|
Hmm, (dusting off my antiquated physics...)
The magnetic field creates forces that act to damp the components of any vibrations that are perpendicular to the field. It does this by inducing currents, in the magnetic material - not the air, which are then converted to heat in that material (unless they are drained in an electric circuit of some sort).
So, there is an energy coupling, but it's independent of the air.
Am I missing something?
Paul Ebert |
|
|
| Paul Ebert |
| quote: | Originally posted by Paul Ebert
The magnetic field creates forces that act to damp the components of any vibrations that are perpendicular to the field. It does this by inducing currents, in the magnetic material - not the air, which are then converted to heat in that material (unless they are drained in an electric circuit of some sort).
|
Thinking about this further, I'm not saying that the magnetic field drains all, or even a majority, of the vibration. I do think that the 'string' would drain quite a bit. Perhaps the way to think about this is that the magnetic field preloads the string 'bearing', by increasing the tension on it and thereby making it a more effective energy drain. But, I do think that some energy would be converted to heat.
The main point is, however, that this may not be any less effective at draining energy away from the cartridge than a typical physical bearing. It all depends on the strength of the magnetic field and the elasticity of the string. At least that's how I see it (which could very well be wrong...).
Paul Ebert |
|
|
| fdegrove |
Hi,
| quote: | | The magnetic field creates forces that act to damp the components of any vibrations that are perpendicular to the field. It does this by inducing currents, in the magnetic material - not the air, which are then converted to heat in that material (unless they are drained in an electric circuit of some sort). |
Interesting.
Are you sure about this?
If so, any idea on how to find more technical info on the net?
Cheers,;) |
|
|
| fdegrove |
Hi,
In case we're both in need of a refreshment course:
ERIC WEISSTEIN
Cheers,;) |
|
|
| Paul Ebert |
| quote: | Originally posted by fdegrove
Interesting.
Are you sure about this?
|
Yes, this is interesting stuff. I feel fairly confident about it, but it has been over 20 years :eek: since I studied it in college.
| quote: | Originally posted by fdegrove
In case we're both in need of a refreshment course:
ERIC WEISSTEIN
|
What an amazing resource. Thanks!
Paul |
|
|
| ticovski |
Can anyone be kind and explain to me how is regulated antiskating on Schroeder design
Thank you,
Ticovski:confused: |
|
|
| mgreene |
It appears that the twist in the thread applies the antiskating.
If you look at the materials on the Shroeder website, in the owner instructions, he shows how the curled knob at the top of the arm pillar, which captures the string, has an inner hex screw. The inner screw appears to set the spacing between the magnets and larger kurled screw applies twist to the monofilament line applying antiskating.
Or at least that's how it looks :cool:
Mike |
|
|
| ticovski |
Thank you, think that now understand :-)
Another (two) questions:
How to calculate effective mass of tonearm, any formula;
and how much of the force do we need in between magnets (5, 10, 15... kg)
Regards,
Ticovski |
|
|
| Paul Ebert |
| quote: | Originally posted by ticovski
Another (two) questions:
How to calculate effective mass of tonearm, any formula;
and how much of the force do we need in between magnets (5, 10, 15... kg)
|
I don't know how to calculate effective mass. My plan for my DIY arm is to 'reverse engineer' it empirically by using the HiFi News and Record Review test record to determine the resonance and, then, calculate the effective mass based on that. But, this is an after-the-fact approach and I haven't performed it yet. Based on my experiences (BTW, my arm is very different - it's a linear air-bearing arm), I got very lucky.
Regarding magnetic field strength, I would think that the stronger the better would apply (as long as the string could handle it, of course).
Paul Ebert |
|
|
| peterr |
| quote: | | How to calculate effective mass of tonearm |
I asked the same question some time ago and got a very thorough reply from Dice45 and Jeremy Epstein:effective mass
At the time I made an excel-sheet to do the calculations but I am afraid to have lost it :scratch:. Sorry. |
|
|
| mgreene |
I had pretty much planned to do as the same as Paul and just take a shot in the dark - but the question did cross my mind. I figured that if I looked hard enough on the web, and in my old references I could probably find something on the subject of tonearm mass.
In any case, the carbon fiber set-up looks like the least amount of work and will thus result in the least amount of dissapointment if it doesn't work out :bawling:
I figured the wood arms could come later.
Mike |
|
|
| ticovski |
Thank you for the link Peter,
I read reffering postings a few times and have some understanding about effective mass now, but don`t understand what is final formula. If you accidentally find your excel sheet I would appreciate if you would send me a copy. Otherwise I don`t see how to do calcs. I like to know what I am doing.
Thank you,
Ticovski |
|
|
| hifidaddy |
| quote: | Originally posted by Paul Ebert
Regarding magnetic field strength, I would think that the stronger the better would apply (as long as the string could handle it, of course).
|
Hi Paul,
I have a Schroeder No.1 tonearm (even wrote the test report for http://www.tnt-audio.com), and can tell you that the magnets of the Schroeder tonearm have about 10kgs attracting force.
regards,
Hartmut from Munich |
|
|
| konstantin |
Here are some pics of my DIY Turntables and Schroeder tonearm clone. I'll post some more detail pics as soon as i get my digital camera back (Did you heard that Chris?:goodbad:).
Meanwhile, anyone want details of the cosntruction feel free to mail me.
Regards
Konstantin
ktzivleris@hotmail.com[IMG]http://[/IMG] |
|
|
| konstantin |
| And..........Another one |
|
|
| mgreene |
WOW! That is beautiful work.
I think many here will be interested in the actual machining plans in terms of how the magnets are connected to the base and arm :bigeyes:
As a side note to Hartmut, I recieved my magents yesterday - although very strong, they dont seem to have 10KGs of attraction. One set, about 8mm wide and 6mm tall could lift about 2KG. Ones about 12 X 10 mm - I could not seperate with hand strength.
Konstantin, any comments or advice about the magnets you used?
Regards
Mike |
|
|
| konstantin |
Sure. The magnets i used are Neodymium rare earth magnets.
They are actually Grade N40, and they are 6mm X 6mm size rod.
The N40 Grade are powerfull. You can't seperate them easilly
:scratch:
Regards |
|
|
| mgreene |
Thanks K,
I just got a few generic neodymium samples off eBay to experiment on. I assumed that there would be different grades but hadn't gotten that far yet.
Did you drill through your arm magnet to mount it?
It has been suggested here that drilling in these magnets is quite challenging.
Mike |
|
|
| konstantin |
Mike,
There is absolutely no way to drill these magnets without destroy them. Neodymium is Very hard but is also very corrosive and even if you drill them you will take of some of the hard Chromium they have on the surface to prevent corrosion. What you can do is to order predrilled magnets as i did. 6mm X 6mm rod with a 1.5mm hole in the middle.
Regards |
|
|
| AuroraB |
I can get varius predrilled Neoymium magnets here in Scandinavia, from 10x3mm to 16-20-35 mm dia and 3.5 to 5.5 mm thickness, holding strengts are listed from appx. 0.8 to 3o kg for the largest..
Has anyone made some seriuos thoughts on what strength would be the optimum...??
What kind of wire, in terms of stiffness..??
Antiskating would be a combination of wire stiffness and magnet, or just by the magnet pull vs. distance..?? |
|
|
| mgreene |
Mr B.,
Note that Hartmut said that his original model Schroeder's magnets have 10KG of holding force. The newest Schroeder Reference arm apparently has more powerful magnets. Konstantin's magnets are grade N40 - the grades go up to N50.
I have not been able to figure out yet if the holding strength is the same number quoted by magnet manufacturers as the "coercive force", i.e., KOe. If so this would seem to be a generic holding force for the grade of magnet as opposed to the actual holding force for a magnet sized for our work here.
Can someone with a physics or other suitable background, help us here?
Mike |
|
|
| fdegrove |
Hi,
| quote: | | Can someone with a physics or other suitable background, help us here? |
Could do but it would take me several pages.
Try to use a search engine such as Google and type in magnet strength.
You'll find numerous sites giving you all the theory.
Cheers,;) |
|
|
| mgreene |
Hi Frank,
I generally try to get the info on the web, as you suggest, before making an open inquiry. Even looked in a couple of physics textbooks. I did not find an answer to the question asked above in either venue.:confused:
What manufacturers of neodyium magnets generally do not list is a "lifting strength" number analogous to the number quoted by Hartmut.
Of course, the easy answer is simply to follow Konstantin and get reasonably sized magnets in grades at or above N40.
BTW: Schroeder's patent can be accessed here:
http://l2.espacenet.com/espacenet/b...++02095736A1+I+
Perhaps those speaking german can give us the gist of enabling design parameters.
Mike |
|
|
| fdegrove |
Hi Mike,
| quote: | | I did not find an answer to the question asked above in either venue |
You mean what the N# stands for?
Well, it's just a guess, I heard from a cartridge manufacturer that the N stands for North type of magnet and the number the ckass off lifting strenght.
Also, he said that there's more than one standard of classification...seems to make it easier on us.:rolleyes:
INTERESTING READ
Cheers,;) |
|
|
| mgreene |
Thanks Frank,
Interesting read.
I've had a brain storm however, I will simply harrass a manufacturer for this information:bulb:
Mike |
|
|
| Paul Ebert |
| quote: | Originally posted by mgreene
Thanks Frank,
Interesting read.
I've had a brain storm however, I will simply harrass a manufacturer for this information:bulb:
Mike |
You might want to check out:
http://www.fieldlines.com/section/magnets
as well. I've had a few discussions with the guy who runs wondermagnet.com and he seems fairly knowledgable.
Paul Ebert |
|
|
| krishu |
;ktin
How did you fix the string? Knot? Screw?
How much is the distance between the neodyms?
@everybody
since i am german i could read the patent paper of the schröder arm. In this document nearly the whole construction of the bearing is described. It is written in a very scientific language so that i am too lazy/stupid to translate the whole. The drawings show nothing less than the text tells about the basic construction.
It is told that neodym magnets are the best and that the string must be not elastic. Also something about oil dampening is told there, but i think this is not interestning at the moment.
It is described, how the aluminium around the magnets influence the magnetic field to force the arm to good behaviour.
cheers
christian. |
|
|
| fdegrove |
Hi,
I didn't spot it at first but from the drawing alone you can actually accurately copy the whole design.
If anyone needs help translating the German text, I may be able to help out.
Tchues,;) |
|
|
| mgreene |
Christian and Frank,
In regard to the patent, I was just curious to know if there was anything in the claims that wasn't obvious from the drawings.
For instance, some magnet companies make steel holders for disk shaped magnets like these and I wondered if this was a good solution. Now, Christian mentions something in the patent about alumium enhancing the magnetic field. That is the kind of info I am interested in.
BTW: altavista and other translation programs do not do much with long, multisyllable germanic words - so, no help there.
In regard to the distance between the two magnets, this info is in the arm setup instructions on Schroeders website. He writes that the thickness of a business card is the starting point - if the magnets get too close or touch the cartridge will start to skip - anybody planning to use their $7K Clearaudio to test with?:clown: I assume that the string is something like 50 pound test, leader - i.e., fishing line. Leader material is usually much tougher (non-stretch) than regular line.
Regards
Mike |
|
|
| AuroraB |
Just read the patent script briefly. Must study it more carefully tonight,-
aluminium cannot enhance the magnetic field...??
However,- he does mention eddy currents being induced in the bottom alu holder - as a damping mechanism.
People has questioned the possibillity of drilling the Nd Magnets, but the patent script also sketches the use of a drilled upper pole piece on the opposite side of the air gap. This can be drilled to hold the thread...the drawings in the patent script really speaks for themselves..
Fly line backing is indeed a good idea for the string/thread. There is also multifilament fishing lines on the market with incredible strength vs. the line thickness. One brand here in Scandinavia is called "Fire Line", but there shure is alot of others. |
|
|
| berlinta |
Hi everyone,
Yup, it's me(Frank Schröder), the guy who's work by now enjoys the privilege to be copied. No need to worry, I have nothing against DIY enthusiasts, enjoying a few nights in the basement workshop, but, - you guys could have made it alot easier on yourselves if you had contacted me directly. My email and my phonenumber can be found on my "webpage".
One word of caution though. If you think that by mere "copying" the drawings in the patent you will end up with an arm that sounds just like one of my own making is optimistic, putting it mildly. Chances are though, that you will end up with an arm that betters anything commercially available for up to 1000$+. BUT, - the inherent superiority of the bearing design is only one of several aspects that "make" my arms.
Let me remark on some of the points raised in previous posts.
Carbon fibre is a decent material to be used as an armwand but exibit a fairly strong resonant behaviour if used "naked".
Yes, neodym magnets can be drilled(heck, anything can be..)
Very little energy is "drained" via the bearing, you'll have to deal with it differently.
Nah, I won't give away too many of my trade secrets(it would spoil your fun, wouldn't it?;-)
And if anyone decides to turn this into a commercial undertaking it will make my lawyer even more rich and you poorer than you'd believe was possible - sorry, I had to add that(no offense meant).
Enjoy the tinkering but more importantly, enjoy the music once you've succeeded.
Cheers,
Frank |
|
|
| krishu |
Hello to everybody,
underneath the lower magnet and above the upper one there shall be discs of high permeability (like frank schroeder wrote in his patent) to increase magnetic field. Therefore those steel cups to hold the magnets one of you mentioned wouldn't be a bad idea. The aluminium's influence to the magnetic field ist more an influence of the magnetic field to the aluminium to force it into its right position/to dampen movement.
So the aluminium won't enhance the magnetic field.
Thank you for the information concerning the distance between the magnets.
For the string, a guitar string may also be used, but must be dampened then. Schroeder wrote that where the string is attached to the arm there should be a cup that will carry some dampening oil.
What advantages/disadvantaghes do you see in using One string or two strings (schroeder did both)...
@Frank Schroeder
I think it is better for us to figure out everything by ourselves. First, to learn. Second, we might (but probably will not) solve problems in a new way, which you can use for your arms. But this is worlds away, now.
If anybody would be interested in producing your design commercially, it would be no good idea anyway. I cannot imagine that it is possible to build those arms really cheaper than you do in good quality. So why should anyone buy them? That means: alles im grünen Bereich.
I attach a scetch that shows just ONE possible way to build it as described in the patent paper and I did construe it.
Cheers
Christian.
 |
|
|
| mgreene |
Hi all,
I sent Frank a friendly email, offline through DIY, as soon as I saw his post. It is possible he didn't get it. Frank are you really willing to correspond with us or did you sign on mainly to inform us of your patent rights?
BTW: It should be apparent that very few of those who can really afford such equipment would waste their time trying to build it.
Nice drawing Christian - and thanks everybody for pointing out my poorly chosen word - "enhance". Even I know that Al is non-magnetic.:nod:
regards
Mike |
|
|
| berlinta |
Hello Mike,
I did get your mail, please see my private response for an explanation why I didn't respond any sooner, sorry again..
BTW, informing you guys of the patent wasn't neccessary, someone had already posted the proper link. Previous (negative) experiences led me to this remark, I won't mention it again.
The drawing is very good indeed, leaves out some important details though. And the shape of the upper polepiece is not quite correct. Build it and tell me if you managed to achieve equal VTF and azimuth from beginning till the end of the record...
Gotta run, pick up some groceries...
Have a great weekend.
I'll be back,
Frank |
|
|
| konstantin |
Dear Mr. Schroeder,
It is very sad that you do not see DIY Audio things the way other designers do, like Nelson Pass to mention only one.
The reason of existence of the DIY Audio community is sharing of knowledge of the so called HI-END equipment, that are most of the times too overpriced (and many of us can not afford) and NOT to solve anyones financial problems.
It would be great if you could only share your knowlegde with the DIY Audio community instead of terrorise it with lawyers and courts. I bet that you started your business as a DIYer.
Regards K.
Keep an open mind. It helps. (I lent this from someone in here) |
|
|
| fdegrove |
Hi,
| quote: | | It is very sad that you do not see DIY Audio things the way other designers do, like Nelson Pass to mention only one. |
This maybe be true but the fields of operation are quite different, tonearms and amps are hardly comparable.
While I admire Nelson for his approach, I do not expect a tonearm designer to adopt the same attitude.
The markets are just too different.
| quote: | | It would be great if you could only share your knowlegde with the DIY Audio community instead of terrorise it with lawyers and courts. I bet that you started your business as a DIYer. |
Yes, it would be great but it seems to me that your understanding of business is ....errrr.... a little limited.
I fail to see where Frank Schroeder threatened with lawyers, he said he had negative experiences in the past and I'm sure he's not the only one out there...
I often find myself in non-disclosure situations too, if I break that agreement I can just as well say goodbye to my future...
Surely it's up to Frank to decide whether he's willing to unveil anything about his design or not?
Crickey, count yourself lucky he responded at all.
You seem to take it for granted that any design out there falls into the public domain as long as it is for DIY purposes, unfortunately for you that is just not the case.
Frankly, I regret your response and if it were to be my designs I would refrain from any futher help.
I don't mean to sound harsh, just want you to look at things from a designers perspective, hope you don't mind.
Cheers,;) |
|
|
| berlinta |
Dear Konstantin,
It was never my intention to terrorize anyone with my lawyers, nor, as I said before, do I have anything against the DIY community. As you correctly guessed I did start out as a DIYer - essentially true for 90% of the "real" high end companies.
I replied to mgreene in private explaining why/how previous negative experiences with other manufacturers have raised my caution levels, I prefer to refrain from public namecalling so don't make me elaborate on this any further.
I'll happily provide you with advice but please don't expect me to publish exact drawings, measurements, material sources,etc... As someone here had said: "we'd like to find out on our own" - after all isn't that where half of the fun is?
The topic of (over)pricing has been discussed many times on each and every audio forum. What it comes down to is that certain components are very service sensitive(turntables: matching, setup...) whereas others are less so(amps, cd-players). Believe me, very few people know how to set up a turntable so that it performs 100%. Most if not ALL distributors/dealers won't even touch a component that leaves the competition in the dust if the margin on it doesn't allow them to cover their expenses. Not going that route simply excludes the option to make Hifi a living.
And there are many more people out there who couldn't tell an amp from a tuner than those who debate the virtues of teflon versus cotton as an insulator.
BTW, which other commercial designers do you mean besides Nelson Pass who publish blue prints of their original/recent work on the net?
Frank(fdegrove) was right on the money(pun intended) that - not only in my case - agreements between me and other manufacturers/distributors exist whereby I just can't give out or even license my product to someone else because they depend on me as a supplier and also want to take advantage of the "exclusive" nature of the product(strong point in this industry). It might not be to my liking but that's the nature of the game.
Ask me questions about my arms - and no one has so far - and I'll answer them as thoroughly as it is possible - see above.
If I didn't have an open mind I'd be building gimballed arms ;-))
Cheers,
Frank Schröder
P.S.: I much prefer to comment on technical instead of business issues in the future. |
|
|
| krishu |
Hi
@Frank Schröder
Here goes the first(?) technical question: We saw your arms having one ore two strings. (I know its everytime one string, but the arrangement looks like two...)
For the two string version I see the advantage of a low "bearing point" as well as I think it is more comfortable to replace a string. And the neodyms do not need to be drilled.
For the one string arrangement I see advantages in easier set-up etc.
I, personally, tend to build the two-string type because I expect it to be done easier. Any warnings? What chose you? why?
And: Do you want to tell us something about the string?
I noticed you using a different shape of magnet. I cannot really understand, why it would be worse using two cylindrical ones. Agreed, a ball magnet with the center exactly at the "bearing point" would be the best, especially when having warped records. But I see no changing VTF when turning the magnets around their identical axis.
@ all
Prices. Yes, some products are very overpriced. But one must pay not only the material. If someone wants/has to live from such a business, there are some things that must be paid: Development, distribution, office and workshop rent; machines, taxes and so on...
Recently I made that experience when lathing counterweights for Rega arms like Expressimo Audio does. It seems that they want a lot of money for just a piece of steel. But when I startded to lathe these weights by my own I understood....
MfG
Christian. |
|
|
| berlinta |
Hello Christian,
The bearing point in the single thread version can be almost as low as in the two-thread arm. But the counterweight would then have to be only ever so slighly eccentric to avoid changing VTF when altering VTA(or when playing warped records).
The initial reason for the two-thread version was that in 1980 when I built the first such arm, no Neodym magnets were available to me and I had to use Samarium-Cobalt which takes up more space as you know. It is also more brittle and the two-thread design encloses(protects) the upper magnet entirely apart from offering more space for the magnet.
The single-thread design is not only simpler to set up, it also offers two, more crucial advantages:
a less mass-ive armwand meaning less energy storage(of energy fed by the cart into the armwand). This is a common problem with most unipivot arms(you need to mass load the bearing to avoid bearing chatter).
a shorter thread means less susceptability to airborne vibration, also less initial stretch.
The execution of the two-thread design is simpler though! When experimenting with different thread materials it makes it a lot easier to exchange threads.
Do not use a monofilament but one of the modern "super" fibers. The knots are the real problem since the surface of the new multifilaments is extremely hard and "slippery". If you're a fisherman you know which knots are best used in this application.
Two cylindrical magnets wouldn't be a problem - if only the suppliers would deliver "perfect" shape magnets. But, as you will find out, any imperfection(like a cylinder with a face that's, say, at an 88° angle to the vertical axis - should be 90° of course..) will result in a uneven distribution of fluxlines in the gap, aka uneven VTF and or azimuth. BTW, fluxline density is highest at the edges, not the center of the magnetic gap.
(A) semi-sphere or ball shaped magnet(s) on the other hand do(es)n't offer the same flux density(attracting force) - using magnets of the same volume.
About overpricing: You forgot to mention the cost of a patent. One needs to sell quite a few arms before only that expense is covered...
Hi Konstantin,
So how does your arm perform in comparison to what you were running before(which arm was that?)
All the best,
Frank Schröder |
|
|
| konstantin |
Hello Frank,
I hope you understand that i did not meaned to offend you, but that lawyer/court thing sounded a little "heavy" in my ears.
I agree, let's stay in the technical part of the "game".
Regards K |
|
|
| fdegrove |
Hi,
| quote: | | I hope you understand that i did not meaned to offend you, but that lawyer/court thing sounded a little "heavy" in my ears. |
Don't worry about it, I think Frank Schroeder explained the why for his position.
I was just afraid you'd chased him away.;) |
|
|
| krishu |
Hi
@Frank Schröder
Thank you for your explainations. If further questions emerge I will be back here and if not you'll see some pics of the results then.
Cheers
Christian |
|
|
| konstantin |
Dear Mr. Schroeder,
The arm i used before the construction of the clone was a Moerch UP-4, which was easily "bitten" by the clone.
Well, the UP-4 was sold and a DP-6 is on the way.
I also made some comparison tests with Simon Yorke's unipivot with the same results.
I'm very curious to compare the clone "side by side" with an SME-V.
Best regards
K. |
|
|
| hifidaddy |
| quote: | Originally posted by konstantin
The arm i used before the construction of the clone was a Moerch UP-4, which was easily "bitten" by the clone.
Well, the UP-4 was sold and a DP-6 is on the way.
I also made some comparison tests with Simon Yorke's unipivot with the same results.
I'm very curious to compare the clone "side by side" with an SME-V.
|
Konstantin,
I am not Mr.Schroeder, but as you might have seen from my test report on TNT web site, I have some Pluto tonearms (I have an older 2A and a newer 8A) and I prefer listening to my Schroeder, though the Plutos have their own strong sides, especially in the bass region. I also once had an SME V. The Schroeder is way better than the SME. In fact I rate the SME V not much better than the Moerch UP4, which is an excellent affordable tonearm.
regards,
Hartmut |
|
|
| Paul Ebert |
| quote: | Originally posted by berlinta
The drawing is very good indeed, leaves out some important details though. And the shape of the upper polepiece is not quite correct. Build it and tell me if you managed to achieve equal VTF and azimuth from beginning till the end of the record...
|
Thinking about these statements led me to one of those 'stupid' questions that one can only ask, usually because said one is completely missing something obvious. So, here goes...
Consider what happens when an arm such as we are considering experiences a warp. The front goes up causing the upper magnet to tilt towards the back. Since the magnets are configured as opposite polarity, the back experiences an increase in attraction due to it's gap being reduced and the front experiences a reduction in attraction. If the differential in attraction is enough this will cause the arm to continue to pivot until the magnets touch in the back. Even if it is not enough to lift the front of the arm, it represents a force that the arm must overcome when it goes down the other side of the warp.
This strikes me as a problem. What am I missing in this picture?
As to achieving equal VTF and azimuth across the record; I'm stumped. Unless it has something to do with the horizontal angle of the cartridge with respect to the arm tube axis (what's this angle called?).
Thanks.
Paul Ebert |
|
|
| berlinta |
Dear Paul,
Not a stupid question at all!.. But, as with any Unipivot arm(this design is NOT a true unipivot, though!), the center of gravity of the whole moving assembly is below the pivot point. As a result, the tracking force increases as the cart/arm "travels" up hill. The effect you described would ameliorate this "unipivot "- flaw (to a degree at least) and should therefore be welcome. In practice it is inconsequential, since the variation of the tracking angle caused by warped records is very small , consequentially the upper magnet doesn't get tilted enough to show such behaviour. On top of that, the other end is raised by a similar distance so that the overall flux density remains the same(close enough ...).
As for your second question, - the armwand can rotate(slightly) around it's axis and horizontally too, off course. If the magnets used aren't perfectly centered/drilled(same for the pole pieces), or if they're not cut perfectly the effect you described first will then indeed have a negative effect. Imagine two discs(the magnets) with magnetic "hotspots" on their surface(same as imperfections which are weak spots). As they get closer to each other while the arm travels across the record, the attracting forces vary and, depending upon their location on the surface, the VTF and/or Azimuth will be affected.
In other words, adjusting the magnets is no simple task.
Build it and then measure VTF at the beginning and then the end of the record. No change? Well done!
Cheers,
Frank |
|
|
| RogueAngel |
Hi all
I'm a new member hereand I ran across this thread. I thought you all might be interested in seeing my version of the "schroeder" tonearm. 
It replaced the standard tonearm on a Denon DP-62L. I just finished construction this past weekend and am still in the process of fine tuning.
I did the test mentioned by Frank and found my tracking force varies by 0.2 g with no apparent change in azimuth.
Has anyone else tested theirs? or would like to exchange experiences?
Bobbi |
|
|
| Paul Ebert |
Looks great, Bobbi! Very well done! Care to fill us in on materials used and design decisions / features?
Also, how did you measure the VTF?
Thanks.
I've been thinking about the problem of magnetic strength variation within a ring and I wonder if a smaller diameter magnet would be better. Taking this to an extreme, perhaps a cylindrical pair of magnets of, say, 1/8" diameter would work well. Can anyone think of a downside to this approach?
Paul Ebert |
|
|
| RogueAngel |
| quote: | | Looks great, Bobbi! Very well done! |
Thanks Paul!
| quote: | | Care to fill us in on materials used and design decisions / features? |
Big question! As I think you can tell, the support structure is acrylic....chosen mostly for ease of tooling. I thought for appearance, the mixture of clear and black would look good and I am quite pleased with the look. The arm is a brass tube (originally intended to be aluminum - but the tube was too thin) with the headshell assembly fashioned from solid brass stock. The counterweight is stainless steel. Wiring is 33ga Cardas with Cardas cartridge clips and Eichmann bullet plugs at the phono input end. The magnets I chose are non-sintered - so, I gave up a bit in field strength, but they seem to be working well. All set-screws etc. are stainless steel. The lifter was obtained from the manufacturer in Japan.
Adjustability is almost too much .... as I have spent hours, literally, adjusting each parameter. Offset angle, VTA, VTF, overhang, and antiskating are all adjustable as in the Schroeder except that in mine the VTA adjustment is loaded with a stainless steel spring in lieu of the concealed adjustment in the original.
| quote: | | Also, how did you measure the VTF? |
VTF was measured with a digital guage with +/- 0.1 gm accuracy. I think the thickness of the scale is influencing the readings and there may not be quite as much variation as the scale indicates. I have found the the angle of the vertical support can produce large variation in VTF. I played with the angle and got as much as a 1.0 gm variation from inner to outer groove.
Having only attempted speaker construction previously, I was a bit reluctent to commit a lot of funds to this project, not knowing if it would even work. The difference over the original arm is quite startling, especially in much tighter bass, much better detail, improved dynamics and a much lower noise floor. The improvement over the original Denon arm is NOT subtle! In fact, due to my beginner's luck, I'm now thinking about making a second arm, with much better materials and a stronger magnet.
| quote: | | I've been thinking about the problem of magnetic strength variation within a ring and I wonder if a smaller diameter magnet would be better. Taking this to an extreme, perhaps a cylindrical pair of magnets of, say, 1/8" diameter would work well. Can anyone think of a downside to this approach? |
If you can find a 1/8" diameter magnet with adequate strength, I think the smaller the better. I believe it would lessen any areas of field variations and would also lessen any problems maintaining the consistency of the gap between the magnets during arm rotation. Has anyone tried various magnets to see what effect they have?
Bobbi |
|
|
| Paul Ebert |
Bobbi,
How did you implement anti-skating?
Thanks.
Paul |
|
|
| RogueAngel |
Paul,
The knob above the suspension string is threaded into the top suspension arm. There is a smaller allen-head type bolt that is threaded axially through this bolt. The "hook" that captures the string is passed through another axially drilled hole that passes through the smaller bolt. Basically, one is used to adjust the gap between the magnets and the other is used to place a small counter-clockwise pre-twist on the string. This pre-twist acts to balance out the arms natural tendency to travel inward. If you read the user's manual posted on Frank's website, he gives a great description of how to make this adjustment.
Bobbi |
|
|
| krishu |
Hello to everybody and especially to Frank Schröder
I am lathing a schroeder inspired tonearm at the moment and have not decided which magnet to use yet.
There are two sizes ready to go in: D15×H5mm and a smaller one measuring just 10mm in diameter. Which one should i use? Both are Neodym N40 or N50 (i do not remember exactly).
What would be advantages/disadvantages of a bigger/smaller magnet? Will increased magnet force lead to any problems?:scratch:
Your help is appreciated.
Cheers
Christian. |
|
|
| berlinta |
Hello Krishu,
Making the magnet larger means you have to increase the diameter or rather the strength of the thread(=higher friction). Eventually you will end up with a thread that is too thick to allow for a suitable adjustment range/evenness for the antiskating.
You could make that thread longer but then it will pick up more airborne vibrations.
Increasing magnet size/strength also increases the damping(sometimes there is too much of a good thing..)
What do you do about shielding the magnetic field?
Properly implemented 10mm x 5mm(N50) should suffice...
Cheers,
Frank |
|
|
| krishu |
Hi Frank;
thank you for your quick response.
I will make all metal parts out of bronce, "behind" the magnets small steel cylinders in the same size as the magnets. I will use standard steel (like C45, ST35 ...) for that. This is what I understood from your patent paper.
Using the smaller magnets will make it easier to glue in the arm pipe (more contacting surface). the arm pipe will be carbon fibre.
the magnets i have are N48 15x5 and 10x4mm. So you say the smaller one would be sufficient?
Or should i go for 12x5 N48? (do not know if this is available yet)
Thanks again
regards
Christian. |
|
|
| berlinta |
Hi Christian,
If you stick with simple pole pieces - in german: Polronden oder Polrueckschlussplatten - you should go for the 12 x 5mm magnets.
Avoid glueing! I don't use any glue in the construction of my arms.
Don't use a plain carbon fiber wand(except for prelimenary tests), if you must use it, you need to dampen it internally or externally.
Sorry, I'm on vacation right now, gotta go...
Cheers,
Frank |
|
|
| krishu |
Hi Frank;
uups, the 12x 5 is not available; so I will have to use the 15x5... for a 12" arm.
The carbon fibre pipe will be dampened, of course.
So when not using glue: how do you manage to keep the magnets in place? Screws? ;o)
Have a nice holiday!
Cheers
Christian. |
|
|
| berlinta |
Hi again,
The magnets are press fitted, which makes the maschining time consuming since they vary(sample to sample) in diameter by as much as 0.1mm in diameter. Batch to batch variation can be even higher.
Other joints are either press fit or thermally bonded(in german: aufgeschrumpft).
Greetings from the pacific coast... :-)
Frank |
|
|
| jcarr |
Hey Frank:
>Greetings from the pacific coast... :-)<
The better to increase your physical distance from Martina and Terry to the maximum extent possible, I suppose. :D
Also on the Pacific coast but still surrounded by chaos ;), jonathan carr |
|
|
| berlinta |
Hi Jonathan!
Where exactly are you? Nonwithstanding the absolutely breathtaking displays of nature's prowess(I took my family to Mt. St. Helens yesterday), another mountain(the Olympos, haha) makes it almost as difficult to raise my jaw off the floor(I know this is off topic , sorry...), - and I do get to enjoy it more often :-)!
You'll hear from me soon,
Cheers,
Frank |
|
|
| RogueAngel |
Frank,
Glad to hear you are enjoying our fair state of Washington. I hope the rest of your vacation goes as well! :)
Bobbi |
|
|
| jcarr |
Frank:
>Where exactly are you?<
Tokyo, Japan. ADSL and irregular sleeping hours are what bring us together.
>another mountain<
My 4th mountain is currently also in the processes of revision, and it is clearly becoming taller and more beautiful.
Speaking of travelling, I strongly recommend you to visit Cosmos Hi-Fi in Ciudad Real, Spain. Even at the very worst, Cliff's main system must be among the 10 best-sounding audio systems in the world, and most probably it ranks within the top 5. Needless to say, it made any place in Frankfurt seem like a joke, and a very, very bad one at that.
>You'll hear from me soon.<
Looking forward to it!
take care, jonathan |
|
|
| fdegrove |
Hi,
For bookings and reservations:;)
COSMOS HI-FI
RONDA DE ALARCOS, 18,
13002 CIUDAD REAL
SPAIN
TEL: 00 34 926 273 127
FAX: 00 34 926 273 206
E-mail: info@ (**** to avoid spam) cosmoshifi.com
Hasta la vista,;) |
|
|
| RogueAngel |
I've decided to build another. While relatively happy with the first, I know there are areas where improvements can be made. While the first was mainly acrylic, this one will be fashioned from a few different metals.
I've already have the new magnets - 1/2"x1/8" N45 and am constructing steel backers for them. The magnets will be installed in an aluminum housing.
The arm tube will be multi-layer. Brass outer tube followed by an aluminum tube followed by a ceramic tube. I plan to use a dampning material in between each layer. The ceramic tube is a multi-bore type with 4 bores.
That's about as far as I've gotten so far.
In the meantime I'm enjoying prototype 1.
:) |
|
|
| fdegrove |
Hi,
| quote: | | The arm tube will be multi-layer. Brass outer tube followed by an aluminum tube followed by a ceramic tube. I plan to use a dampning material in between each layer. |
That's likely to be rather tricky...CLD, right?
But why the extra inter-layer damping? Isn't that going to compromise rigidity?
Cheers,;) |
|
|
| RogueAngel |
CLD? Yes. The tubes I'm using are thin walled. So, my thought is that with very thin layers of damping material ( approximately 0.002") between the aluminum and brass tube layers that rigidity will actually be increased since the tube will be acting as a much thicker walled tube. The brass and aluminum tubes have a wall thickness of 0.014". The aluminized ceramic tube is solid excpt for the borings. I chose the ceramic for it's very high strength to weight ratio.
I haven't decided yet on a damping material, so if any one has advice or good sources, I'd be grateful. |
|
|
| RogueAngel |
Hi All,
I've completed my new Schroeder clone. :)
The latest uses stronger magnets, a brass and aluminum support structure, and a new brass/aluminum/ceramic arm.
The results are better low level information retrival and what I can only describe as bringing all the details back into an integrated whole.
I am very happy with this latest effort. I am recieving a Transfiguration Temper Supreme at the end of the week to replace the Sumiko LMX Premier I am using now. I'm hoping this will offer another dramatic increase in performance.
Here's some pic's:
http://www.htguide.com/bilder/image...0II%20-%201.JPG
and another shot
Bobbi |
|
|
| livemusic |
Hi Bobbi,
Well done, beautiful DIY project! One could see, the DIY'ers efforts could be well rewarded!
What kind of damping material between the arm layers you have choosen in the end?
Just one comment: your tonearm leads are arranged in such a way, the antiscating force is increasing towards record center. Actually, it should be done vice versa; Carlo Morsiani provide good reasons why in his site.
Regards and congrats!
Michael |
|
|
| ktigerb |
Beautifulllll work Bobbi
I'm naturally :p :p :p with envy
regards
keith birss |
|
|
| RogueAngel |
Thanks Michael and Keith :) ,
This was really a lot more work than my original, but I definitely feel the effort was worth it.
Michael, thanks for the reference to Morisani's efforts on adjusting anti-skating. Trying the wire running opposite to the present routing will be easy. I'll let you know if I can hear any difference.
The damping material I used is a spray damping material called Quiet Kote made by Cascade Audio Engineering. It was the only material I could find which would lend itself to filling the small annular space between the three co-axial arm rods. The arm was assembled with the damping still wet and allowed to cure in place. I'm sure there are probably better ways, but this seems to be working. Although I don't really have anything to compare it to.
Bobbi |
|
|
| RogueAngel |
Hi All,
Well the Temper arrived on Thursday, and I am sooooo glad I built in a lot of capacity for VTA adjustment. I had to raise the rear of the arm about an inch just to keep the rear of the cartridge from hitting on a warped LP. I was fiddling with adjustments all day Friday and Saturday, but Sunday I finally got to sit down and really listen
The sound is better than I ever imagined it could be. Soundstage is 3 dimensional, bass is tighter and deeper than before and cymbals have taken on a very natural sound. But what is most amazing is the mid-range. The vocals from the Indigo girls are very distinct. Vocals on Guns-n-Roses live album are completely intelligble. And everything is natural and effortless. I am just in awe.
I picked up a lot of information on this thread, and it really helped.
Bobbi |
|
|
| fdegrove |
Hi,
| quote: | | And everything is natural and effortless. I am just in awe. |
Glad to here it, Bobbi.
You did a fine job, congratulations.:)
What cartridge, electronics are you using?
Cheers,;) |
|
|
| RogueAngel |
fdegrove
| quote: | | What cartridge, electronics are you using? |
The cartridge is the Transfiguration Temper Supreme, going through a Rotel phono pre-amp and Rotel receiver. My speakers are all DIY and can be seen here:
My system: (the pics do not show the new cartridge.)
| quote: | | You did a fine job, congratulations. |
:)
Bobbi |
|
|
| fdegrove |
Hi,
| quote: | | going through a Rotel phono pre-amp and Rotel receiver. |
Very good value for the bucks...
Hop over to the "Tubes" section of the forum and we'll wip up a pre and amp that matches the frontend in no time.;)
You'll be hearing what the frontend can really do....
Cheers,;) |
|
|
| Jarno |
Hello all,
I know this thread is not very active anymore, but browsing through the messages I found the problem of drilling very brittle material (Neodynium). Most metals can be drilled quite easily using EDM, or, Electric Discharge Machining. Although the required tools are not something you conjure up in an afternoon, there quite a few workshops who can provide you with this service. It is quite a slow process (although there some specialized processes that can be quite fast), so the costs might be a bit prohibitive. Just my 0,02€
Greetings,
Jarno. |
|
|
| Paul Ebert |
Since Jarno 'resurrected' this thread, I'll ask a few questions:
Does anyone know of a good way to make a smooth, crimp free bend in a small diameter (say, 1/4" OD) tube? The tube would probably be titanium. I need a way to make the horizontal offset angle bend (of the headshell with respect to the tube). A 1/4" tube bending tool would be great, but I have no idea where to find such a thing. Any ideas?
Does anyone know if there is a 'standard' number of degrees for this angle? If so, might you know what it is?
I'm back to considering building one of these since my efforts at reducing the horizontal effective mass of my air bearing tangential tonearm haven't been satisfactory. How to work the headshell and this angle are the most significant challenges in my mind at this point (which probably means I'm missing something or delusional or both... ;) ).
Thanks.
Paul Ebert |
|
|
| berlinta |
Hi Paul,
Your best bet would be to fill the tube with fine grain sand, heat it up to at least 250°C and use a wooden pole/rod of not too small diameter to bend/wrap it "around". If you are to use such a wand for one of my arm-designs be warned that you will need an additional counterweight, offset to maintain lateral balance. This will compromise the simplicity of the design unless you settle for a single, low slung counterweight that will have to be severely offset(giving the whole thing a somewhat "kaputt" look :-)
Oh, btw, why Titanium? Remember, this design doesn't depend upon fast energy transfer to dissipate parasitic resonances in the armboard...
There are several exel sheets that offer Baerwald and/or Loefgren arm geometry figures(offset angle is one of them) on the net(search the vinyl asylum archives..)
Good luck,
Frank Schröder |
|
|
| krishu |
Hi Jarno,
you do not need to drill the magnets when drilling the steel discs behind them to carry the string.
Apart from this, it is hard to drill the magnets. It is very likely to destroy them by doing so...
Cheers
Christian. |
|
|
| Jarno |
Hello Christian,
I haven't looked into the actual construction of the tone-arm, I just came across the question of drilling hard material. Being an mechanical engineer I know you can make holes in all sorts of metals using EDM or spark-erosion (and some other rather high tech processes), this technique doesn't exert pressure on the metal you want to "drill" therefore, when making a hole using EDM you don't run the risk of cracking the material.
I think this thread is rather interesting, maybe I will try to make an arm using this method. Oh well, have to finish my Laadegaard first.
Regards,
Jarno |
|
|
| Paul Ebert |
| quote: | Originally posted by berlinta
If you are to use such a wand for one of my arm-designs be warned that you will need an additional counterweight, offset to maintain lateral balance. This will compromise the simplicity of the design unless you settle for a single, low slung counterweight that will have to be severely offset(giving the whole thing a somewhat "kaputt" look :-)
Oh, btw, why Titanium? Remember, this design doesn't depend upon fast energy transfer to dissipate parasitic resonances in the armboard...
There are several exel sheets that offer Baerwald and/or Loefgren arm geometry figures(offset angle is one of them) on the net(search the vinyl asylum archives..)
Good luck,
Frank Schröder |
Thank you for the response, Frank. OK, I'll skip the bend, perhaps doing as you did with the Model 1. I'll look for the Baerwald spreadsheet (I vaguely recall that the Baerwald geometry is more common - is that correct?).
Why titanium? Well, I could have my friend with a lathe make a tube for me out of some gorgeous wood, now that you mention it! ;) I was able to purchase titanium tubes with a very nice finish for my tangential arm (I am not good at finishing metal), so I figured I'd use that again without giving it much thought. So, what criteria should I use for tube selection? Besides wood, I could probably use carbon fiber (from a kite frame piece) or ceramic (McMaster-Carr sells high alumina ceramic tubes quite inexpensively).
Thanks again,
Paul |
|
|
| berlinta |
Hello Paul,
Yup, as far as the stiffness to mass ratio is concerned titanium, certain ceramic composites and even carbon fiber are excellent choices. But, looking at a typical length, outer and inner diameter for a tonearm wand, they all have a fundamental resonance(and multiples of that) quite far up(3-7kHz typically). The reasoning that the high frequency content of most records is low(therefore it is supposed to be a good thing to push the fundamental structural resonance as high up as possible) doesn't apply here since the equalization of the signal encoded in the groove leads to an overproportionally high amount of high frequency "mechanical energy" aka vibrations being fed into the arm(wand). The best armwand is one with as low a susceptability to being excited across the audio band as possible. Any pronounced spike(s) will give your reproduction an artificial quality, (tiny) broadband deviations are easier to live with.
If you use titanium make shure you dampen the armtube sufficiently, - lots of room for experiments!
Cheers,
Frank |
|
|
| WolfgangB |
Hi everybody,
Could somebody give me the measurements of following parts of the Schoeder Type 2 tone arem (see piocture):
1. Diameter of tonearm tube
2. Diameter and height of counter weight
3. Diameter and height of tonearm base (aluminium)
Thanks in advance.
Kind regards,
Wolfgang |
|
|
| Claus |
Hi
Another metode to bend a tube, would be fill the tube with water and freze it down, then bend the tube while the water is frosen.
Claus |
|
|
| AuroraB |
((---or fill it with with fine sieved sand.......))
Sorry, wasn't reading back......
but heating it in addition will help in the bending process.
Alu get's markedly softer above 150 deg C. |
|
|
| Magura |
All you guys that have made a tonearm, why is it you dont make drawings of them to compare and help others to start from where you are and develop things further, rather than starting from scratch???
If you made just reasonable back of a napkin drawings, you would be able to help the project to develop, instead of just imagining what eachother makes.
I have been following this thread for a while. I would like to make a complete turntable sometime this summer...if all else equal...but the approach you guys are taking dosnt make it easier. I am a toolmaker in diecasting...have all the reight machinery for such a project. If i sterted from the point you are at now...i am quite sure i could bring a lot to this project, instead of having the same trouble you had years ago.
Many well made project you guys have got here. A much higher quality of work than you see in the other sections of the forum.
Magura:) |
|
|
|
