90mm still has a huge advantage over a conventional 9" (223mm) arm in terms of rigidity and resonance. It is worth noting that the majority of VTA error is caused by the slope of the surface of the record and very little due to the pivot angle. True a shorter arm does have greater VTA error but has to have an effective length of less than 30mm before pivot angle becomes predominant.
cheers
Niffy
cheers
Niffy
Hi Niffy,
No, it's the same one I've been using since the prior change, it's the same weight as the former Alu block but mass is distributed differently.
Colin
No, it's the same one I've been using since the prior change, it's the same weight as the former Alu block but mass is distributed differently.
Colin
Hey lexx,
As tolerance matched I mean by bearing tolerance in respect to free spin, and least amount of play. Both bearings have equal amount of friction free movement laterally.
Colin
As tolerance matched I mean by bearing tolerance in respect to free spin, and least amount of play. Both bearings have equal amount of friction free movement laterally.
Colin
Colin and all,
I've read most of the posts in this thread with great enthusiasm. I have been comparing this double rail double bearing carriage with the arms you guys were building last summer with ball bearing races. After many iterations of the arm in this thread can anyone comment how this arm trumps the double ball+double alu angle? I can see that Chris G built both very nicely....is frequency response, imaging, noise sufficiently different with the two glass rods as compared to the 11 mm balls?
Lots of different carts bring tried but I'm also interested in any experimental results with wire types, their impedance and with dressing them away from sources of resonance ie. keeping them off the arm vs. running through the arm or as Chris has done ( and I think Colin) shrink tubing down the arm.
I was just collecting the parts for the ball race arm...should I forget it?
Sean
I've read most of the posts in this thread with great enthusiasm. I have been comparing this double rail double bearing carriage with the arms you guys were building last summer with ball bearing races. After many iterations of the arm in this thread can anyone comment how this arm trumps the double ball+double alu angle? I can see that Chris G built both very nicely....is frequency response, imaging, noise sufficiently different with the two glass rods as compared to the 11 mm balls?
Lots of different carts bring tried but I'm also interested in any experimental results with wire types, their impedance and with dressing them away from sources of resonance ie. keeping them off the arm vs. running through the arm or as Chris has done ( and I think Colin) shrink tubing down the arm.
I was just collecting the parts for the ball race arm...should I forget it?
Sean
Hi Sean,
I'm an advocate of the ball race arm, but good bearings are needed 🙂. Soundwise it's great, imaging superb and let's the magic out of any cartridge, you don't hear the arm sound invading into the sonics. Even the four tube, two balls has a complexity that makes the two tube two race such as mine look simple.
I use very fine multi strand enamelled wire that has no influence on the carriage movement, it's very fine but is routed through brass tubing seperate for each channel hot and ground for most of its length. that acts as a shield since it's grounded only at the TT ground. I didn't use shrink tube, just a twist around the arm tube before the cart connection. I'd say pick whichever appeals to you the most, they both seem to do the job 🙂.
Colin
I'm an advocate of the ball race arm, but good bearings are needed 🙂. Soundwise it's great, imaging superb and let's the magic out of any cartridge, you don't hear the arm sound invading into the sonics. Even the four tube, two balls has a complexity that makes the two tube two race such as mine look simple.
I use very fine multi strand enamelled wire that has no influence on the carriage movement, it's very fine but is routed through brass tubing seperate for each channel hot and ground for most of its length. that acts as a shield since it's grounded only at the TT ground. I didn't use shrink tube, just a twist around the arm tube before the cart connection. I'd say pick whichever appeals to you the most, they both seem to do the job 🙂.
Colin
Hi Colin
OK, I'm encouraged to push on with the ball race version. I picked up nice 11 mm steal balls, aluminum angle iron that is 1/2" x 1/8" thick. I have been cannibalizing a Dual and was able to retrieve tiny thrust bearings measuring 4 mm outside diameter. I'm thinking of using them with sprung pins to hold the arm fulcrum in the hanger. Should result in very free vertical movement, virtually no bearing noise...obviously very minimal contact of the cartridge arm with the rest of the assembly.
I'll revisit areas of this thread where you talk about critical arm lengths. I'm sold on a lower slung cw. I'm going with a damped carbon tube within a tube for the arm itself. (Stock found at a local RC hobby shop, which is also a good source of miniature bearings). I've always wanted to do a wood headshell and thought balsa wood would be interesting but according to one poster has a poor damping coefficient? I like the Yamamoto style and exotic woods are readily available in my area...maybe Delrin.
Still getting the plinth together but will post progress and pics when there's something to look at.
Sean
OK, I'm encouraged to push on with the ball race version. I picked up nice 11 mm steal balls, aluminum angle iron that is 1/2" x 1/8" thick. I have been cannibalizing a Dual and was able to retrieve tiny thrust bearings measuring 4 mm outside diameter. I'm thinking of using them with sprung pins to hold the arm fulcrum in the hanger. Should result in very free vertical movement, virtually no bearing noise...obviously very minimal contact of the cartridge arm with the rest of the assembly.
I'll revisit areas of this thread where you talk about critical arm lengths. I'm sold on a lower slung cw. I'm going with a damped carbon tube within a tube for the arm itself. (Stock found at a local RC hobby shop, which is also a good source of miniature bearings). I've always wanted to do a wood headshell and thought balsa wood would be interesting but according to one poster has a poor damping coefficient? I like the Yamamoto style and exotic woods are readily available in my area...maybe Delrin.
Still getting the plinth together but will post progress and pics when there's something to look at.
Sean
Sean,
The best heahsell I found was aluminum, and also easy to work with. My last iteration was by far the best, keeping the highest mass nearest the cart and tapering it up away from the cart to a lighter mass, think as with electronics that energy will seek the path of least resistance to ground itself coupled with the fact that irregular shapes dissipate standing waves much better and break them up.
One thing that can't be underestimated is the cart to headshell integrity I've found, The screws to attach not as important as long as they give a nice secure mating. The low slung counterweight will vary vtf ever so slightly across a warp, but this is not detrimental but an asset riding a warp. Vinyl warp is the only time this becomes an issue, on flat vinyl tracking force is even.
Colin
The best heahsell I found was aluminum, and also easy to work with. My last iteration was by far the best, keeping the highest mass nearest the cart and tapering it up away from the cart to a lighter mass, think as with electronics that energy will seek the path of least resistance to ground itself coupled with the fact that irregular shapes dissipate standing waves much better and break them up.
One thing that can't be underestimated is the cart to headshell integrity I've found, The screws to attach not as important as long as they give a nice secure mating. The low slung counterweight will vary vtf ever so slightly across a warp, but this is not detrimental but an asset riding a warp. Vinyl warp is the only time this becomes an issue, on flat vinyl tracking force is even.
Colin
Hey Colin
I think I'll try aluminum too. I'll have some stock left over from the carriage I'm going to build so should be cool to experiment with.
I've read about damping from many sources so the composite arm should provide some isolation from the carriage. The wires may run through the inner tube....but enough conjecture. I have to get on with building.
I don't play any warped vinyl so hopefully setting up the VTA won't be too tricky. I've always liked the lighter end of the scale for tracking force but I haven't chosen my next cart yet. I will see what he arm comes in at.
Thanks for the ongoing tips.
Sean
I think I'll try aluminum too. I'll have some stock left over from the carriage I'm going to build so should be cool to experiment with.
I've read about damping from many sources so the composite arm should provide some isolation from the carriage. The wires may run through the inner tube....but enough conjecture. I have to get on with building.
I don't play any warped vinyl so hopefully setting up the VTA won't be too tricky. I've always liked the lighter end of the scale for tracking force but I haven't chosen my next cart yet. I will see what he arm comes in at.
Thanks for the ongoing tips.
Sean
Hi Sean,
A last tip, watch the lead wire you use, must be very flexible and buy a lot of
at least 10 bearings to pick the lowest friction pair 🙂.
Colin
A last tip, watch the lead wire you use, must be very flexible and buy a lot of
at least 10 bearings to pick the lowest friction pair 🙂.
Colin
If you don’t buy dry bearings, you need to clean the bearings. I use Goo Off from Homedepot to clean my U-groove bearings for the damping device of air bearing arm. It is powerful stuff. It did a great job. I recommend to sink the bearings in the small amount of solvent and to turn the bearings for about 15 mins. Let the bearings dry and to see if it is good enough. If not, you need to pour fresh solvent and do the same. Be careful and don’t put your fingers into the solvent.
Attachments
If I can't use the tiny pivot bearings I retrieved from my old Dual I will look for matched roller style.
I was looking at the Clearaudio Reference "headshell" and can see how similar Colin's is to it. I was thinking of wood in a similar application. I can see how it would provide damping.
I was looking at the Clearaudio Reference "headshell" and can see how similar Colin's is to it. I was thinking of wood in a similar application. I can see how it would provide damping.
If I can't use the tiny pivot bearings I retrieved from my old Dual I will look for matched roller style.
I was looking at the Clearaudio Reference "headshell" and can see how similar Colin's is to it. I was thinking of wood in a similar application. I can see how it would provide damping.
I was looking at the Clearaudio Reference "headshell" and can see how similar Colin's is to it. I was thinking of wood in a similar application. I can see how it would provide damping.
Great work, Hans. I need to find out more about this arm design.
And thanks for the Vienna Jazz Workshop LP! 😎
This I do not understand. Thomas Bowden got a patent for his linear tonearm. Is a patent necessary?
Local lawyer?s invention drops into the groove | Richmond BizSense
Local lawyer?s invention drops into the groove | Richmond BizSense
Hi,
necessary? of course not.
This device was filed on April 9, 1959 to Mr. D.Mankowitz under US3,006,652 and a similar design was published in Radio Bulletin 1960 by Mr. Percy Wilson.
It's a patent he probabely could't defend anyway, because the only differences between his arm to those designs is the make of the fixed and the sliding carriage from rods or tubes.
Besides, the arm on the pictures looks very low quality missing refinements and features.
jauu
Calvin
necessary? of course not.
This device was filed on April 9, 1959 to Mr. D.Mankowitz under US3,006,652 and a similar design was published in Radio Bulletin 1960 by Mr. Percy Wilson.
It's a patent he probabely could't defend anyway, because the only differences between his arm to those designs is the make of the fixed and the sliding carriage from rods or tubes.
Besides, the arm on the pictures looks very low quality missing refinements and features.
jauu
Calvin
Audiostar and Calvin. Don't judge my device by the crude prototype that I had on hand when the reporter showed up. It actually doesn't even demonstrate some of the key claims in the patent. Patents are subtle things, in some cases it only takes a slight variation to qualify. I filed for the patent because all things considered, it's better to have than not. And, by the way, I made my prototype (several actually) before I discovered the Mankovitz patent. If you want to see what the patent covers, check it out at Patent US9019806 - Low friction linear tracking tone arm - Google Patents.