go for it, you won't be disappointed , as you found out the best characteristic is overall low friction (vertical and horizontal) and depending on materials and construction is easy to achieve very low mass.
one thing I was concern with was the wear (or shatter) on the rods an ball when not using any lubricant, in the Cantus bearing the arm works better without any type of lubricant but in this case I tried with different type of lubricants like mineral, teflon... and finally I got a really nice result using the old and trusty WD40 but in very small quantity as to only leave a film on the "center channel" and on the balls, I don't use it directly, I use a Q tip dipped on the lubricant , no problems with dust neither but I guess this is very depending on the environment or the formation of static and so on...
other interesting approach is the use of self-lubricant type of materials, polymers, nylon...
interesting idea but the friction in the vertical movement is not a issue at all and considering the initial experiments I did with a copy of the Opus Cantus I would say it offers more friction in both planes than this type of design.
but hey!, this is not place for non-inquiring minds.
yes that is something to consider, a good "grip" between the parts to avoid "looseness" of the carriage.
Hi,
Yes, I think, that the fixation of the ball in perpendicular-to-the-rail direction is a requirement.
The suggestions for a 4-point and 3-point sytem fulfill the requirement, while he 2-point system does not.
If a certain amount of friction for the vertical movement is advantageous, the 4-point system will be prime choice.
It seems the easiest to build and also to source parts for.
jauu
Calvin
Yes, I think, that the fixation of the ball in perpendicular-to-the-rail direction is a requirement.
The suggestions for a 4-point and 3-point sytem fulfill the requirement, while he 2-point system does not.
If a certain amount of friction for the vertical movement is advantageous, the 4-point system will be prime choice.
It seems the easiest to build and also to source parts for.
jauu
Calvin
in my case during normal use I only manipulate the back or counterweight side of the carriage, the general technique for manipulating the arm is basically the same as any other pivoting arm with no cue lever, don't grab it and/or use only one finger (the "pinky" finger is good candidate) that's the key for a gentle "touchdown" and "elevation".
if you want you can add a cueing mechanism with a lever to your tonearm.
Ok, at the moment I'm collecting various bits to have a go at putting something together. Trying out the balls on the runners seem to leave the top runners very loose on the balls and easy to topple off. I guess once the headshell and arm are connected it will add a little weight and hold it steady. I've got an idea for the dust problem (very hush hush at the moment, I don't want industrial spies getting hold of my thoughts/ideas 
)
)
yes, when you install the cartridge and counter weight it will feel more solid and as in some unipivot designs is a good idea to place the majority of the weight lower than the pivot point. if you look at the pictures from my first post the rod that holds the cartridge goes under the two rods that forms the upper carriage I tried above it but I concluded it was not as firm. many arms (specially unipivots) take advantage of lowering the center of gravity for stability and it really works.
Well project number 1499 has begun a couple of hours down the shed following a few ideas running around my head and its coming together. Based on Soyuz' idea the base, bottom runners, balls and arm are semi sorted and dry fitted to give me a feeling of how it'll look. What the initial opinion guys?
Still got plenty to do and the head-shell/cartridge holder may be changed depending on weight.
a couple of hours down the shed following a few ideas running around my head and its coming together. Based on Soyuz' idea the base, bottom runners, balls and arm are semi sorted and dry fitted to give me a feeling of how it'll look. What the initial opinion guys?
Still got plenty to do and the head-shell/cartridge holder may be changed depending on weight.
very nice, I really like the use of wood in HiFi products in general.
what cartridge will you use for this project?
one interesting thing is that I checked the condition of the stylus ( JICO sas ) with a high magnification microscope and I was surprise to find almost no wear after more that a year of use with the linear tonearm, although there is a general consensus that the estimate life according to JICO is very VERY conservative but to be honest I have not been gentle with this stylus at all, I even did all my initial experiments when I was going for a Cantus exact copy with the SAS.
the ridges of the stylus looked very clean with a nice reflection of light and symmetrical, it will be interesting to see how long it last and how the wear manifests, too bad I did not keep track for the exact amount of hours in use.
what cartridge will you use for this project?
the total mass can be made very low, the carriage I´m using measures approx. 17 grams including the cartridge.
one interesting thing is that I checked the condition of the stylus ( JICO sas ) with a high magnification microscope and I was surprise to find almost no wear after more that a year of use with the linear tonearm, although there is a general consensus that the estimate life according to JICO is very VERY conservative but to be honest I have not been gentle with this stylus at all, I even did all my initial experiments when I was going for a Cantus exact copy with the SAS.
the ridges of the stylus looked very clean with a nice reflection of light and symmetrical, it will be interesting to see how long it last and how the wear manifests, too bad I did not keep track for the exact amount of hours in use.
I've a very limited supply so end up changing things around and reusing the same ones over and over so it'll either be a Stanton 500 or an Ortofon OM
It's amazing what can be done with a £10 torch, a couple of old mouse balls, some scrappage wood and a few knitting needles I can't wait to hear how it sounds but I've still got to cut a slit down the length of the tube and set the upper rails. Then work out the best way to attach the drop arm for the headshell to attach to it
It's amazing what can be done with a £10 torch, a couple of old mouse balls, some scrappage wood and a few knitting needles
I can't wait to hear how it sounds but I've still got to cut a slit down the length of the tube and set the upper rails. Then work out the best way to attach the drop arm for the headshell to attach to itAs for the use of wood I've got an idea to use bamboo to match in with the turntable
I have a very straight thin piece and I know its lightweight so would suit this job nicely. The wiring doesn't need to pass through which also lends itself to use it. Either that or a carbon fibre arrow shaft very thin and light.
I think the mouse balls may be a little too large for the job (it was a big beggar of a mouse )
The wood body should allow me to fit some type of arm lift contraption though I'm still thinking on how I'll deal with that. And I'll need to arrange some kind of wiring harness. I think the base will have to have a wooden plate under it so will probably fit a couple of RCA connectors on that. As it is at the moment it's a little top heavy so it'll need a support of some kind. All good fun working out the solutions to the problems. Thanks again Soyuz for the initial idea.
I have a very straight thin piece and I know its lightweight so would suit this job nicely. The wiring doesn't need to pass through which also lends itself to use it. Either that or a carbon fibre arrow shaft very thin and light.
I think the mouse balls may be a little too large for the job (it was a big beggar of a mouse
) The wood body should allow me to fit some type of arm lift contraption though I'm still thinking on how I'll deal with that. And I'll need to arrange some kind of wiring harness. I think the base will have to have a wooden plate under it so will probably fit a couple of RCA connectors on that. As it is at the moment it's a little top heavy so it'll need a support of some kind. All good fun working out the solutions to the problems. Thanks again Soyuz for the initial idea.
I've been working a little more on the arm having received the steel balls through the post. It's still in dry fit mode so its not totally set correctly and the cartridge and wiring need sorting out but I put it all together to test the theory. Damn it works and is very smooth and light running. I went with the carbon fibre wand as the lighter stronger option and 7mm balls as opposed to 5mm
The arm can be adjusted for length and I may need to shorten the drop arm to suit the table which is a fairly simple job. I'm pleased with how its going.
The arm can be adjusted for length and I may need to shorten the drop arm to suit the table which is a fairly simple job. I'm pleased with how its going.
when I was testing for the first time I was happy to see that the carriage was very light with very low drag BUT when I started doing the wiring things got bad, the wires added too much drag and I realized it is a critical part of the design if I wanted to get the full potential of the arm, I ended up using solid core enameled copper wire I don´t know the exact diameter but is very thin (I had it in my workbench) other thing I found was that is a bad idea to do the cabling trough the wand so I did it directly to the pins of the cart, I know that a lot of tonearms are made the other way but in my case the experience was not good, I also twisted the wires of each channel to get a better noise rejection and that works well too, in any case I got the least movement interference doing an arc above the arm with the cables something like this (BTW mechanically I did not like thais type of cable at all)
The cables are through the arm at the moment purely to keep them out of the way. My intention is to have them loose as you suggest to allow the least resistance to the flow of the arm. It's surprising how stable it becomes by just hanging the arm to the top runner. It all came together once it was in position.
Next job is to fit a cartridge and to measure it up on the table so that I know how much drop it'll need. Then it's fitting it all together as a hard fit and to get the angles sorted so that the top runner is level on the vertical. The arm itself will probably need to extend forward a fair bit because of the setup on the table. I can't wait to see how a cartridge plays on this arm.
Next job is to fit a cartridge and to measure it up on the table so that I know how much drop it'll need. Then it's fitting it all together as a hard fit and to get the angles sorted so that the top runner is level on the vertical. The arm itself will probably need to extend forward a fair bit because of the setup on the table. I can't wait to see how a cartridge plays on this arm.
Further Experiments!
Hello Everyone
Things are going a bit slower than I hoped due to work commitments. However, I have lashed up an experimental carriage and the results are:
Chris
Hello Everyone
Things are going a bit slower than I hoped due to work commitments. However, I have lashed up an experimental carriage and the results are:
- It's much more stable in all planes than I expected-a very good sign
- The movement of the carriage is very smooth- much less friction than using ball races-this bodes very well for performance.
Chris
Attachments
Hi all,
Things have been going a good bit slower in my shop too, but last night I put together a working model and tested it on several records before retiring for what was left of the night. The music I was playing was stuff I was very familiar with from previous development efforts. This arm appears to be a "super" arm that is conspicuous by its absence. The only thing I am aware of is the music. Way too early to say more. First test was made using an Empire 2000E. Best I've ever heard that cart. Tonight I'm putting on an ADC XLM. The new arm and the Empire 2000 did give a very solid and strong low end. Definitely not a bass resonance issue. Need to hear it with the ADC XLM. To my delight all ringing seems to be gone. Nothing was done for resonance control but I did use a different mounting structure and no decoupling. Will post some pics after installing the ADC and listening for a while. Also need to arrange something to prevent the balls from taking off and exploring the living room floor. I like what I hear so far!
BillG
Things have been going a good bit slower in my shop too, but last night I put together a working model and tested it on several records before retiring for what was left of the night. The music I was playing was stuff I was very familiar with from previous development efforts. This arm appears to be a "super" arm that is conspicuous by its absence. The only thing I am aware of is the music. Way too early to say more. First test was made using an Empire 2000E. Best I've ever heard that cart. Tonight I'm putting on an ADC XLM. The new arm and the Empire 2000 did give a very solid and strong low end. Definitely not a bass resonance issue. Need to hear it with the ADC XLM. To my delight all ringing seems to be gone. Nothing was done for resonance control but I did use a different mounting structure and no decoupling. Will post some pics after installing the ADC and listening for a while. Also need to arrange something to prevent the balls from taking off and exploring the living room floor. I like what I hear so far!
BillG
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.