From the looks of the Cantus and measuring from a photo, I think it is 16mm guessing by the size of the bearing. 2 mm thick.
Lexx21, for the support arm weight is not an issue, in fact fill it with sand to dampen resonances. For the tone arm and counterweight tube, lightweight is an issue. I used CF tubing from a kite shop. FunWithWind dot com SkyShark Carbon P90 tubing. It is super light and stiff.
Lexx21, for the support arm weight is not an issue, in fact fill it with sand to dampen resonances. For the tone arm and counterweight tube, lightweight is an issue. I used CF tubing from a kite shop. FunWithWind dot com SkyShark Carbon P90 tubing. It is super light and stiff.
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For those interested in dimensions, the one I can give is the center of tube to cart mounting bolts is 2 3/8", hope this will help. Ideally this should be adjustable, I originally built the fixed carriage without adjustments, then came to realize that adjustments were indispensable for setting tube length and azimuth. Polycarbonate might be heavier, but not as rigid for a given size compared to carbon fiber.
Colin
Colin
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I found all the parts I needed but the 10 mm glass tubing, so I ordered it on line. I have more than I need so if anyone needs some, I should have three extra tubes (they are 12" long). I' have extra 5/8" CF arrow shaft for the arm tube if anyone needs that (easy to find at a sporting goods shop). Used if for a uni-pivot design and works great with a little foam stuffed in the end for resonance. Shouldn't need foam with a short 2 or 3" arm tube.
Basic mechanical drawing of the arm would be nice to have. You may find some hints, however, when looking at the Clearaudio Statement TT1 arm: http://www.muz.lt/saugykla/failai/Publikacijos/Atsiliepimai/Statement_presskit_07_Eng.pdf; page 13. The armwand is 186 mm long and has a total weight of 24 g.
Hello lexx21
You'd have to have a few basic dimensions to do that. Good luck with that. I tried to get just the height of the glass tube above the LP from vynuhl.addict, to no avail.
Sincerely,
Ralf
You'd have to have a few basic dimensions to do that. Good luck with that. I tried to get just the height of the glass tube above the LP from vynuhl.addict, to no avail.
Sincerely,
Ralf
That's the sort of thing that I am looking for. Height of the tube would impact the VTA, so that has to be correct. I suppose that you can adjust the length of the arm so that it is center line with the spindle of the turntable.
I had thought about using a micrometer to adjust the vta, but that would just allow for fine adjustments.
I had thought about using a micrometer to adjust the vta, but that would just allow for fine adjustments.
Some comparisons of materials
Borosilicate Glass
Density (g/cm3).............................. 2.23
Poisson's Ratio................................ 0.2
Young's Modulus (GPa).................... 64
Mohs............................................. 5.7
Tensile Strength MPa....................... 282
Bending Strength MPa..................... 69
Speed of Sound m/s......................... 5640
Polymethylmethacrylate
Density (g/cm3).............................. 1.18
Poisson's ratio................................. 0.35~0.4
Young's Modulus (GPa).................... 3.2
Mohs.............................................. 3.0
Tensile Strength (MPa).................... 70
Flexural Modulus (GPa)................... 2.9
Speed of Sound (m/s)..................... 1840
POLYCARBONATE
Density (g/cm3).............................. 1.2
Poisson's ratio................................. 0.37
Young's Modulus (GPa).................... 2.0–2.4
Mohs.............................................. 3.0
Tensile Strength (MPa)..................... 55–75
Flexural Modulus (GPa).................... 2.3
Speed of Sound (m/s)..................... 2270
Borosilicate Glass
Density (g/cm3).............................. 2.23
Poisson's Ratio................................ 0.2
Young's Modulus (GPa).................... 64
Mohs............................................. 5.7
Tensile Strength MPa....................... 282
Bending Strength MPa..................... 69
Speed of Sound m/s......................... 5640
Polymethylmethacrylate
Density (g/cm3).............................. 1.18
Poisson's ratio................................. 0.35~0.4
Young's Modulus (GPa).................... 3.2
Mohs.............................................. 3.0
Tensile Strength (MPa).................... 70
Flexural Modulus (GPa)................... 2.9
Speed of Sound (m/s)..................... 1840
POLYCARBONATE
Density (g/cm3).............................. 1.2
Poisson's ratio................................. 0.37
Young's Modulus (GPa).................... 2.0–2.4
Mohs.............................................. 3.0
Tensile Strength (MPa)..................... 55–75
Flexural Modulus (GPa).................... 2.3
Speed of Sound (m/s)..................... 2270
tvi,
what you didn't include was the materials' damping factors.
glass 0.033
acrylic 0.07
polycarbonate 0.033
if the tubes pick up any vibrations, none are going to get rid of it very quickly, the acrylic being the best of the three mentioned.
I'm using carbon fibre (non-twill) tubes for my design, which have a damping factor of 0.061 before modification, they are slid over 3mm steel threaded rods.
what you didn't include was the materials' damping factors.
glass 0.033
acrylic 0.07
polycarbonate 0.033
if the tubes pick up any vibrations, none are going to get rid of it very quickly, the acrylic being the best of the three mentioned.
I'm using carbon fibre (non-twill) tubes for my design, which have a damping factor of 0.061 before modification, they are slid over 3mm steel threaded rods.
Or, we dont rely on the tubes themselves to provide damping factor but a system itself, around the tubes to prevent and transfer vibration away from the tubes. Hence in this application the base should be the biggest mass,. A series of vibration control tuned to.cover the spectrum seems to be the ticket here.
Colin
Colin
Back about a year ago, I suggested this concept on the Cantus Thread. My attempts basically resulted in the magnetic particles separating from the oil over time resulting in a sludgy mess.
For those in the states. Glass tubing.. In different colors
Glass Tubing from The Science Company
For bearings, old hard drives have some very nice small bearings on the swing arms.
Glass Tubing from The Science Company
For bearings, old hard drives have some very nice small bearings on the swing arms.
Hi Colin,
seems to be a bit of misconception here.
If vibrations were to be 'led away' from the tubes, that means they would still vibrate.
Mass on its own does not damp.
'Tuning' resonances just swaps one set of frequencies for another, superimposed on the same general background of vibrations.
And don't forget, these 'pathways' along which you want to send vibrations are two way. A lot can be understood by remembering the old Newton's cradle toy.
Vibrations are best dealt with at source. This is not possible with energy from the stylus/cantilever, but damping can (and should) be added to all the undamped parts of the arm, and its support (along with the turntable and record itself).
With the o rings over the threaded rod and a pressure fit for the glass tube with and o ring inside at each end I've had no further need for damping. We must also take into consideration that in general no damping in itself will cover all of the sonic spectrum. Carbon fiber seems to be pretty flat across the board, since the arm here is so short there is no real need.to.damp the carriage, atleast in my case where the cart mount is 10mm polycarb, and the same with the t piece that holds wand and bearings. There is a set of holes drilled in a + configuration that provides some decoupling between the wand and bearings while maintaining rigidity. If you tap the glass.Tube it's a dull thud, you will never eliminate any of this no matter what you fill it with, you can only.control it of course. Ideally it should not have any significant length.of decay to a tap, as this will cause feedback, all in all pretty simple and can be done by ear.
Colin
Colin