Thanks for posting, sikisa. The headshell looks like the RS Labs type of headshell. Does it have a guiding mechanism or it just free flowing? Can you show us the tonearm in operation? Thanks.
Stepper Motor
Hi super10018,
You are right, a Stepper Motor would indeed be a good idea. I know, because I patented that idea in 1984. I incorporated it in my prototype at that time.
Sincerely,
Ralf
Hi super10018,
You are right, a Stepper Motor would indeed be a good idea. I know, because I patented that idea in 1984. I incorporated it in my prototype at that time.
Sincerely,
Ralf
Going back into a past post, I found Ralf's patent. I only glanced at the pictures and haven't read through the entire patent. In one version the assembly travels in a straight line so it does not use the Birch geometry but it is not a parallel arm either. The other more complicated version uses a curved trajectory. If Ralf allows, I would like to post picture links so people can enjoy observing his creation here.
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Hi Jim,
Patents were good for 17 years in 1984. This idea has been in the public domain for a long time. It would tickle me pink if someone would use a stepping motor in a tone arm servo.
I don't actually know how the Reed people are driving their new tone arm.
Sincerely,
Ralf
Hi directdriver,
I have no objections whatsoever, and thanks for remembering.
Sincerely,
Ralf
Hi Doug,
It is hard to believe how fast time goes by. In 2013 I was introduced to a Professor at Embry Riddle Aeronautical University in Prescott. He was going to help with the design of my tone arm servo. That didn't come to pass for various reasons. While I was patiently waiting for some circuitry to build, I continued with mechanical improvements in my tone arm. I finally came up with a servo of my own design that was so simple, that I could design and build it myself. I spent 2016 listening and testing my 2015 model and designing and building my 2016 model.
Exactly one year ago I attended one semester of CNC programming and operating at Yavapai Community College in Prescott so that I could do my own CNC work on my 2016 tone arm. That tone arm should be finished around Spring Time.
The problem with posting pictures is that, the tone arm has several patentable features which I will lose if I post a picture. I may make my tone arm public if I haven't raised the money to patent the tone arm by the end of 2017.
The main feature of my 2016 tone arm is that, it tracks tangentially with zero error. The servo is of the passive type, consisting of a transistor and a few resistors that anyone can replace.
Sincerely,
Ralf
US Patent #4722080
Thanks for sharing!
Some drawings from the patent that tickle the inventive minds! I just love the fact that not all tangential tracking tonearms have to be parallel trackers, servo or no servo!
Thanks for sharing!
Some drawings from the patent that tickle the inventive minds! I just love the fact that not all tangential tracking tonearms have to be parallel trackers, servo or no servo!
Hi DirectDriver!
This is my tonearm, rare & simple; Tokyo Sound ST 1400, and turntable Teac TS 85 magne float, mod system hanging over.
https://drive.google.com/file/d/0BxEsgYDL-A8Nb3dJM3loSkR0Tmc/view?usp=sharing
https://drive.google.com/file/d/0BxEsgYDL-A8Ncm9XblRzbzhfMHM/view?usp=sharing
https://drive.google.com/file/d/0BxEsgYDL-A8NX3g5anJtRzdPLXM/view?usp=sharing
This is my tonearm, rare & simple; Tokyo Sound ST 1400, and turntable Teac TS 85 magne float, mod system hanging over.
https://drive.google.com/file/d/0BxEsgYDL-A8Nb3dJM3loSkR0Tmc/view?usp=sharing
https://drive.google.com/file/d/0BxEsgYDL-A8Ncm9XblRzbzhfMHM/view?usp=sharing
https://drive.google.com/file/d/0BxEsgYDL-A8NX3g5anJtRzdPLXM/view?usp=sharing
Thanks sikisa! Looks like the stylus is below the pivot point. I don't see any guiding mechanism attached to the headshell so I assume it is free flow like the RS Labs headshell. Does it track tangentially?
Whilst loving the elegance* of some of the designs has anyone (and I may have missed this earlier in the thread) tried one of the many X-Y platforms available? A much more industrial solution but for those of us without the skills and access to machining might be interesting.
*Part of me hates the idea of, say using a RPi to control steppers when a couple of transistors correctly applied can do it, but sometimes £4 of 32 bit processor does make sense.
*Part of me hates the idea of, say using a RPi to control steppers when a couple of transistors correctly applied can do it, but sometimes £4 of 32 bit processor does make sense.
I don't believe this thread covers that solution in the earlier posts. Since this thread is mostly about passive mechanical solutions, I think someone should open a new thread on servo arms. But if you have new ideas in that genre, particularly the really simple DIY-able kind, I don't object to posting here either... because I broke the rule numerous times!
That's what I thought. Perhaps a Garrard Zero 100 or Thales Simplicity type of articulating headshell will help. You can also try something like this, as suggested in post #770.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Or replace the TWO strings with ONE rigid low mass rod:
An externally hosted image should be here but it was not working when we last tested it.
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I did over lunch read the first few hundred posts and did note that Rabco's were out of the question but was too embarrassed at the time to admit it. I'll mull more. I suspect size may be a problem, but I have a solution in that space. As an inveterate skip diver, when they threw out the mount that the back projection unit was fitted to in the office I just HAD to have it. Gives me some room in experimenting with modular turntable parts.
Attachments
I've pondered a stepper or similar non-parallel tracker for a while (ok, years). It seems if you know the angle of the arm, you know where to put the pivot. Thus, if the arm has a simple thick sheet of acrylic somewhere near the pivot, you can shine a laser through it to a PSD. The beam offset gives you the angle, and you can map that to the drive mechanism. I built the arm but have never had the time to do the rest of it.
Hi billshurv,
As far as I know, those X-Y stages are quite expensive. For that money one could hire a skilled machinist to make one's favorite tone arm.
Sincerely,
Ralf
Hi billshurv,
There are a few hundred dollars worth of aluminum extrusions in that unit. I would not have passed it up either. (note the spelling of Aluminum)
Sincerely,
Ralf