To add a little thorn into the equation, with a double linear bearing how do you keep it all stable?. It will want to topple forward and or backward 😀
Colin
Colin
The lower two tracks would need to have three tubes and three balls, two balls in one groove and one in the other to make the system stable.
Rethinking my previous post. The two bearing sets would be independent of each other, ie you could hold the middle rail still and still move the carriage and vice versa. Therefore my original statement is probably true and only one bearing set would move at a time.
That will teach me to engage my brain before posting or not to post when I have a 3am start.
The oil bath damping idea is interesting though.
Niffy
Rethinking my previous post. The two bearing sets would be independent of each other, ie you could hold the middle rail still and still move the carriage and vice versa. Therefore my original statement is probably true and only one bearing set would move at a time.
That will teach me to engage my brain before posting or not to post when I have a 3am start.
The oil bath damping idea is interesting though.
Niffy
I say 'keep it simple'-before we know where we are we will have something resembling the Eiffel Tower! I also don't believe lubrication is necessary as the balls roll along the rail. This is the lowest friction design I've played with and (unlike using ball races) I have never had any problems from the off. Dressing the wires in the correct way and supporting them properly (see my arrangement) is in my mind a more fruitful pursuit.
Chris
Chris
Hi Chris,
I agree, it's all too easy to over engineer 🙂, even harder to KISS. I've had the same success from the get go with ball races, but I'm thinking I had the geometry sussed out quite well for it working so well. It's awesome to see more linear threads popping up, regardless of how we get there the end results is astounding wouldn't you say?.
Colin
I agree, it's all too easy to over engineer 🙂, even harder to KISS. I've had the same success from the get go with ball races, but I'm thinking I had the geometry sussed out quite well for it working so well. It's awesome to see more linear threads popping up, regardless of how we get there the end results is astounding wouldn't you say?.
Colin
Hi again,
You might have noted the GOOCQ (get out of crap quick!) preposition😀:
After spending hours yesterday pouring over "ANGLING FOR 90° - tangential pivot tonearms", I thought it could be useful seeing how much of the arguments against LT's could be irradiated using this arrangement.
I had considered a stabilised rail (Niffy), although stability is not really a concern for the benefit of my (probably academic) musings; in any case a single rail could easily be stabilised by adding mass below the centre of gravity – take a look at the last pic in #11 to get a better idea of what I mean.
Everything's packed away so I can't play – really annoying!
You might have noted the GOOCQ (get out of crap quick!) preposition😀:
so please just humour this as a simple exploration – as Chris intimates, there are quite a few other considerations that would most obviously provide greater overall improvements to the design, but as with any consideration – and there will be many – if we take each parameter to the n'th degree, the sum of the whole should prove even greater: even if some feasible inclusions are deemed ultimately inappropriate.
After spending hours yesterday pouring over "ANGLING FOR 90° - tangential pivot tonearms", I thought it could be useful seeing how much of the arguments against LT's could be irradiated using this arrangement.
I had considered a stabilised rail (Niffy), although stability is not really a concern for the benefit of my (probably academic) musings; in any case a single rail could easily be stabilised by adding mass below the centre of gravity – take a look at the last pic in #11 to get a better idea of what I mean.
Everything's packed away so I can't play – really annoying!
Hi Pete
Sorry to hear about your problem! I use 5mm balls on 6mm diameter rods as you know. Works perfectly
Chris
Sorry to hear about your problem! I use 5mm balls on 6mm diameter rods as you know. Works perfectly
Chris
That's only a problem when you sit on a broken plastic chair!😱
Looking very slick Pete🙂
Ball resonance and interaction with rails (or rather rail material) will obviously be a significant factor here - eager to understand your findings when you try the different sizes. BTW, did you weigh your carriage? Interested to see folk's thoughts on different carriage masses (although so far, wand + counterweights are additional factors too).
Carriage + cart + counterweight weights 104grams. I should get new balls (5mm) next week. Then I can try it.
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Please forgive me for reiterating my circumstances, ie: can't play because all my stuff is packed away in storage pending an actually not too far away move (in Thailand you take a deposit – which we did – and if the buyer reneges you keep the deposit [not so bad], although you start from scratch again if it screws up - so I'm completely stuck for the time being until the balance is paid; this can take months!). I'm going out of my brain not being able to play with this!! Argh!!
Can we summarise any of our findings? - I can't, obviously; but:
1 – we (ok, you!) have defeated the (for my concern for LT in general) issue of non-mechanical grounding
2 – have simplified LT to the most apparent threat to useability re. complex air supply
3 – ok, bit of a stretch here, but I believe when you have individual jets of air you encounter pockets of high pressure resistance that makes a linear track other than linear – I had a design based on the ladergaard that employed a series of identically sited jets over the top of the carriage that would a) help this situation, and b) facilitate higher pressure usage (that would otherwise destabilise the carriage) – these measures now redundant with this design.
4 – lateral friction is a direct component of arm + carriage mass vs rail/ball trueness & surface quality
Have I missed anything?
If not, I can fix "4".
Cheers, Fezz
Can we summarise any of our findings? - I can't, obviously; but:
1 – we (ok, you!) have defeated the (for my concern for LT in general) issue of non-mechanical grounding
2 – have simplified LT to the most apparent threat to useability re. complex air supply
3 – ok, bit of a stretch here, but I believe when you have individual jets of air you encounter pockets of high pressure resistance that makes a linear track other than linear – I had a design based on the ladergaard that employed a series of identically sited jets over the top of the carriage that would a) help this situation, and b) facilitate higher pressure usage (that would otherwise destabilise the carriage) – these measures now redundant with this design.
4 – lateral friction is a direct component of arm + carriage mass vs rail/ball trueness & surface quality
Have I missed anything?
If not, I can fix "4".
Cheers, Fezz
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Fix for “4”:
1) Mass: Given that the “wand” as such can be all but eliminated, the residing mass values pertain only to the counterweight. Thus, the counterweight can be eliminated, or rather circumvented, by means of a magnetic coupling. Divisible, or adjustable magnetic rails can be employed in conjunction with a simple magnetic follower attached to the flexibly oscilatrous portion of the carriage. This method has the added benefit of transforming the device into a dynamically rather than statically balanced unit. I believe this would be the first incarnation of a dynamically balanced LT.
2) Given the ~3” travel of the carriage, the linear races can be divided into sections; these sections at start and end of play (outside modulated disc area) will correct any accumulated misalignment of balls within the overall context of the linear ball race(s).
3) A portion equivalent to the tangential area of the source disc segregates the two linear races. On either carriage or base track, as deemed most fitting, is sited a soft iron bar – very narrow (thus light if sited on the carriage) and equivalent to the tangential area of the source disc. Conversely, on the opposing, is sited a magnet whose affect is variable by means of threaded adjustment – this nullifies the requirement of mass to enable effective contact between bearing surfaces, and facilitates variability in terms of friction, stiction, and mechanical adhesion.
There! Public knowledge, and anyone can use it; moreover no one can patent it from under my nose... 😀
1) Mass: Given that the “wand” as such can be all but eliminated, the residing mass values pertain only to the counterweight. Thus, the counterweight can be eliminated, or rather circumvented, by means of a magnetic coupling. Divisible, or adjustable magnetic rails can be employed in conjunction with a simple magnetic follower attached to the flexibly oscilatrous portion of the carriage. This method has the added benefit of transforming the device into a dynamically rather than statically balanced unit. I believe this would be the first incarnation of a dynamically balanced LT.
2) Given the ~3” travel of the carriage, the linear races can be divided into sections; these sections at start and end of play (outside modulated disc area) will correct any accumulated misalignment of balls within the overall context of the linear ball race(s).
3) A portion equivalent to the tangential area of the source disc segregates the two linear races. On either carriage or base track, as deemed most fitting, is sited a soft iron bar – very narrow (thus light if sited on the carriage) and equivalent to the tangential area of the source disc. Conversely, on the opposing, is sited a magnet whose affect is variable by means of threaded adjustment – this nullifies the requirement of mass to enable effective contact between bearing surfaces, and facilitates variability in terms of friction, stiction, and mechanical adhesion.
There! Public knowledge, and anyone can use it; moreover no one can patent it from under my nose... 😀
Innovations can be stolen. If you're broke there's little you can do unless you feel that you can do a better job than anyone else - please read here: http://www.diyaudio.com/forums/lounge/255266-sick-death-ip.html#post3904303
"Joy to the World!" (Jeremia was a bullfrog...) 😀
Hi Jezz.
From your description it sounds like you are planning on using magnetic attraction instead of a gravity mass counterweight. If I understand you correctly you plan to place a small piece of iron on the arm tube just in front of the pivot and then have a strip of magnetic material just above it that attracts it relieving most of the mass of the arm/cartridge.
This would certainly allow the removal of the entire rear section of the arm tube.
I believe a better option would be to replace the small piece of iron with a magnet and use magnetic repulsion instead with the magnetic strip being below the arm tube. I think that this would be much more stable. You would need th position the magnet close to the pivot so that the gap between the magnets will vary as little as possible as the arm pivots.
Have you any ideas on how to make the magnetic strip?
By removing the counterweight you will also reduce the vertical effective mass of the arm. You may require a heavier headshell to compensate.
You have obviously put a lot of thought into this, keep the ideas coming.
Niffy
From your description it sounds like you are planning on using magnetic attraction instead of a gravity mass counterweight. If I understand you correctly you plan to place a small piece of iron on the arm tube just in front of the pivot and then have a strip of magnetic material just above it that attracts it relieving most of the mass of the arm/cartridge.
This would certainly allow the removal of the entire rear section of the arm tube.
I believe a better option would be to replace the small piece of iron with a magnet and use magnetic repulsion instead with the magnetic strip being below the arm tube. I think that this would be much more stable. You would need th position the magnet close to the pivot so that the gap between the magnets will vary as little as possible as the arm pivots.
Have you any ideas on how to make the magnetic strip?
By removing the counterweight you will also reduce the vertical effective mass of the arm. You may require a heavier headshell to compensate.
You have obviously put a lot of thought into this, keep the ideas coming.
Niffy
Hi, Jezz
Sorry about your housing problem. When do you think you'll be re-planted?
Got your message, tried to reply, no luck. I am at awolff761@hotmail.com.
Sorry about your housing problem. When do you think you'll be re-planted?
Got your message, tried to reply, no luck. I am at awolff761@hotmail.com.
I have mine built.....unfortunately I've developed a problem with my tone arm wires.....AND one side of my phono stage is gone.....*Poof*
I did mange to "watch" the album spin with the cartridge/arm on it.....lol.
Very smooth movement, even with an off center album I tried.
My bottom rails are solid Pyrex tubing, the top rails are carbon fibre tubes, same as the wand itself. The bottom rails sit on a flat piece of aluminum with a small
carbon rod used as a spacer. This separates the bottom rails a bit to let the bearings "seat" deeper in the groove to stabilize the arm when manually moving it back and forth. Seems to work, but I've spent my fair bit of time on the floor
searching for bearings.
Its pretty well a knock off of ChrisG design, but it seemed to make sense to me.
The arm weighs in at 42.8 grams with the Sumiko cartridge and counter weight attached.
I did mange to "watch" the album spin with the cartridge/arm on it.....lol.
Very smooth movement, even with an off center album I tried.
My bottom rails are solid Pyrex tubing, the top rails are carbon fibre tubes, same as the wand itself. The bottom rails sit on a flat piece of aluminum with a small
carbon rod used as a spacer. This separates the bottom rails a bit to let the bearings "seat" deeper in the groove to stabilize the arm when manually moving it back and forth. Seems to work, but I've spent my fair bit of time on the floor
searching for bearings.
Its pretty well a knock off of ChrisG design, but it seemed to make sense to me.
The arm weighs in at 42.8 grams with the Sumiko cartridge and counter weight attached.
Hi Niffy & all,
Forgive the absence, felt a bit piXXy after my anarchist thread got pulled🙄
(I'm just a big baby!😀)
Yes & no -
Yes, you can use magnetic coupling to eliminate rear portion (including weights) of "wand" (although in fact you do not need a wand as such).
The process of eliminating the wand incurs a destabilisation of the carriage mechanism, hence the second magnet & track – yes, you can use a strip & point magnet mechanism, but this will not be required – a soft iron strip will suffice. This mechanism is merely to tie the carriage to the track, same as an F1 car uses spoilers rather than mass. Ergo – we have eliminated the mass factor associated with LT's, and accomplished dynamic balancing to a far better degree than previously attained on radials using springs: I had intended patenting this idea (for radials & LT's) but frankly, WGAS!?
Point is, the described arm completely defeats any radial incarnation of an LT because it:
a) is truly linear
b) is truly mechanically grounded
c) answers all previous complaints against LT's
d) does not require a proliferation of external crap in order to function!
The only downside, as previously cited is the inability to perform rta otf or rather (and more accurately) azimuth on-the-fly. Actually, this can be achieved electronically, but at the expense of carriage mass.
Hi awolf,
Thought this might happen within the next month, but thanks to the general state of crap over here it looks like we lost our buyer... (bxllxxxs..!)
"Oh give me a home where the buffalows roam & I'll show you a house full of cow-shXt!" - (either Billy Connely or Jasper Carrot)
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Dissemination:
For the sake of not losing IP to someone else...
magnetic c/weight:
Magnets do that weird thing of going 4:1 at a distance of 2:1; in order to effect a truly linear force you must use two static magnets in conjunction with a dynamic unit which of course is attached to the “wand”. The tricky thing is to find the appropriate degree of magnetic coupling between all units which is accomplished through a combination of magnetic force, leverage, and distance. Although dynamically balanced tonearms (using springs) are cited as being more linear than statically balanced units, they are obviously NOT linear – if they were, ANY degree of mass would see them reach their full travel. As it is, any doughnut knows that a small mass attached to a spring gives a shorter stretch than a high mass – that's why high compliance cartridges require low mass arms and vice-versa.
It is entirely plausible to use electromagnets in order to achieve vtf otf.
For the sake of not losing IP to someone else...
magnetic c/weight:
Magnets do that weird thing of going 4:1 at a distance of 2:1; in order to effect a truly linear force you must use two static magnets in conjunction with a dynamic unit which of course is attached to the “wand”. The tricky thing is to find the appropriate degree of magnetic coupling between all units which is accomplished through a combination of magnetic force, leverage, and distance. Although dynamically balanced tonearms (using springs) are cited as being more linear than statically balanced units, they are obviously NOT linear – if they were, ANY degree of mass would see them reach their full travel. As it is, any doughnut knows that a small mass attached to a spring gives a shorter stretch than a high mass – that's why high compliance cartridges require low mass arms and vice-versa.
It is entirely plausible to use electromagnets in order to achieve vtf otf.