I am setting the air pressure at about 20 psi. There are a total of four pads. My table with associated structure may weigh about 45 lbs. So, each pad supports about 11 lbs.
Being one who wished he could afford the big lab cushion of compressed air whose trade name I cannot remember- I doubt that would work with my plinth which is close to hundred pounds with the platter.
Same problem with the magnetic levitation. Magnets strong enough to hold that up would certainly have an effect on the cartridge.
No question finding a way to make the smaller "balloons" work would be ideal. I would prefer one for each corner. The spring are not bad they are under fairly good control but I know the air cushion would have much less sway.
I am going to attempt something like Super's approach. Thanks for the inspiration
Same problem with the magnetic levitation. Magnets strong enough to hold that up would certainly have an effect on the cartridge.
No question finding a way to make the smaller "balloons" work would be ideal. I would prefer one for each corner. The spring are not bad they are under fairly good control but I know the air cushion would have much less sway.
I am going to attempt something like Super's approach. Thanks for the inspiration
That is really interesting. Those HONDA folks are very clever. I am a HONDA guy I replaced my 18 years old Integra R with a CIVIC R. My last car. I plan on it lasting me until the end. Needless to say no automatics involved. Though I would not discount one of those double clutch contraptions but I love the simplicity of the manual and I do not need lighting shifts anyway. Makes sense when microseconds count at the track but ultimately pretty silly for the public roads. Luckily there was no temptation.
Sorry for the detour STRAIGHT TRACKER but PRR is , by far, one of he most interesting and knowledgeable fellows here. Good to think he might check in on occasion ...
Take care,
PRR is a legend! If you are interested in pro audio, his posts in other forums are a treasure trove of knowledge and wisdom.
I think my point was: parts for 2002 Accords may be VERY much less expensive than any Porsche piece. Aside from being not too overpriced in 2003, by now stockrooms are being dumped to make way for more-profit newer parts. If exact condition is not fussy, salvage parts are still abundant.... I cracked the taillight of the 1996 Odyssey and got a lightly scratched but fully functional replacement cheap on eBay. Toyotas are also now universal parts donors, but I don't know them so well.
As it is I do not think either of those engine mounts would do me any good!
I would love a fluid filled cushioning device with some simple valves to act as a damper for turntable plinths. Not being capable of making such a thing I will simply have to use springs.
Now to hear the latest in Straight Tracker's novel bearing experiments.
I would love a fluid filled cushioning device with some simple valves to act as a damper for turntable plinths. Not being capable of making such a thing I will simply have to use springs.
Now to hear the latest in Straight Tracker's novel bearing experiments.
You must be one of the people who never reads any of the preceding posts. Not any different from the folks who think Straight Tracker is going to use a disk brake as a turntable platter.
True professionals go one of two ways: either they tell and describe everything or they tell nothing about their projects in order to sell them.Here's a third case...If you like to imagine what others pretend to disclose...that's a 4th case of delusion...
@ Rickmcinnis: Same problem with the magnetic levitation. Magnets strong enough to hold that up would certainly have an effect on the cartridge.
Sorry to disagree on this comment. My Mag levitation hold up the 5 Kg platter, plus 0.5 Kg puck plus the TA that is about 1 KG and leaning out a bit plus the structure of the floating plus the solid bronze and stainless bearing very well and using MC cart Denon DL 103 I never never had any problems or negative effect on the cart. It depend on how you make it. Above on 16 years of using it, therefore I am sure is not a case but a fact based on reality that mag levitation did not effect at all the Denon DL 103. Th eTA inner wires do not have even th Stroud wire, just the 4 cart wires..........
The small problem with mag levitation to engineer is to have a solution to keep the two repelling mags entered as they off set themself and stronger is the weight to be folded up stronger is the off set center power to control. But there are simple solution to it it the holding weight is not very high such as 30 or 40 Kg.
Rgds
Adelmo
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There always seem to be so many absolutes when people discuss options, designs, theories. Having read here of people advocating the use of fluid dampeners/engine mounts from cars, designed to support 100KG to 150KG engines, vibrating at between 750hz and 60,000hz resisting huge torques and using dampening fluids possibly unable to be changed to lower viscosities more suited to a 10kg task, and others say categorically that another idea WILL NOT WORK is a testament to closed minds. (Not wishing to offend as we are all guilty of that from time to time).
Adelmo has stated that a technology works, and I believe him. It seems (to me at least) an ideal answer to the problem, no noise, passive in action, cheap to design and develop. If really needed using a MU metal shield from an old AV speaker driver as a top or bottom cup (or both). Is holding a few magnets near a compass or even a pickup (if non risky) beyond consideration/testing as well or considering any mountings position and distance from susceptible components. As I have found, sometimes (after due consideration) there is no substitute to a bit of R&D, messing about with hardware and gauging results.
Adelmo is it possible that you could post a sketch/picture of your design as this would enlighten all of us? Many thanks.
As a last suggestion to try to be helpful, how about a partially inflated pneumatic tyre inner tube? Play with different pressures or fillings. Lots of different sizes to play with.
Anyway. All the best for your project.
Adelmo has stated that a technology works, and I believe him. It seems (to me at least) an ideal answer to the problem, no noise, passive in action, cheap to design and develop. If really needed using a MU metal shield from an old AV speaker driver as a top or bottom cup (or both). Is holding a few magnets near a compass or even a pickup (if non risky) beyond consideration/testing as well or considering any mountings position and distance from susceptible components. As I have found, sometimes (after due consideration) there is no substitute to a bit of R&D, messing about with hardware and gauging results.
Adelmo is it possible that you could post a sketch/picture of your design as this would enlighten all of us? Many thanks.
As a last suggestion to try to be helpful, how about a partially inflated pneumatic tyre inner tube? Play with different pressures or fillings. Lots of different sizes to play with.
Anyway. All the best for your project.
Hi,
This is a detail of one out of 3 mag unit that hold up my TT floating type one. As you can see there is an aluminum case, inside goes a pivot that have one of the upper magnet. The bottom magnet is fixed to the base unit of the aluminum case. As mentioned since two rejecting mags also off center themselves, I used a kind of O R to keep centred the mags. The lateral off set power of the mags increase according to the mags rejecting power , I.E according to the weight they need to hold up.
However in building a TT there are many way to achieve things...
My goal was to have a good isolation system simple and reliable.
But perhaps other TT might have different goals, such as isolate but also control some kind of frequency, therefore In my opinion something using springs may achieve better this result. I would not consider things engineered for the use of different weight and frequency for a TT as I have read above, but I am not a designer therefore it is just a simple opinion.
My mag system have some short coming, but overall I am happy to have used it and made it. Is not too soft therefore can hold up may Kg ( not soft like the old Thorens for example... ) and isolate well. Having the motor pod separated from the plinth I do not need too much to control vibration, also my bearing even though is a traditional one has a very very low rumble/noise level.....
However there are soooooo many ways to skin the cat, mine was just a sharing information, nothing more nothing less.
Rgds
Adelmo
.
This is a detail of one out of 3 mag unit that hold up my TT floating type one. As you can see there is an aluminum case, inside goes a pivot that have one of the upper magnet. The bottom magnet is fixed to the base unit of the aluminum case. As mentioned since two rejecting mags also off center themselves, I used a kind of O R to keep centred the mags. The lateral off set power of the mags increase according to the mags rejecting power , I.E according to the weight they need to hold up.
However in building a TT there are many way to achieve things...
My goal was to have a good isolation system simple and reliable.
But perhaps other TT might have different goals, such as isolate but also control some kind of frequency, therefore In my opinion something using springs may achieve better this result. I would not consider things engineered for the use of different weight and frequency for a TT as I have read above, but I am not a designer therefore it is just a simple opinion.
My mag system have some short coming, but overall I am happy to have used it and made it. Is not too soft therefore can hold up may Kg ( not soft like the old Thorens for example... ) and isolate well. Having the motor pod separated from the plinth I do not need too much to control vibration, also my bearing even though is a traditional one has a very very low rumble/noise level.....
However there are soooooo many ways to skin the cat, mine was just a sharing information, nothing more nothing less.
Rgds
Adelmo
.
Hi,
By the way something like this below if you have budget may work, ... or something used to lift up doors that can be purchased from the bricolage shop might be adapted ......
pneuance-audio-pneupod-pneumatic-isolation-feet
Rgds
Adelmo
By the way something like this below if you have budget may work, ... or something used to lift up doors that can be purchased from the bricolage shop might be adapted ......
pneuance-audio-pneupod-pneumatic-isolation-feet
Rgds
Adelmo
Adelmo.
Thanks, they look great. I had considered an upturned/opposing cone format, with the magnets placed in an angled annular groove on each half/part. This would act to self center and float when loaded. Initial location could be achieved by using a loose fitting screw/bolt/pin, just to hold the parts together, such that when loaded this item is clear and free from touching other parts. I had done some design work on the idea and bought some neo magnets to gauge repelling forces (which were surprisingly high), but I then found my holy grail of a CD player, my work priorities changed and I decided not to continue. How would you say your turntable performs in comparison to ready made ones? What did you compare it with?
Many thanks.
Thanks, they look great. I had considered an upturned/opposing cone format, with the magnets placed in an angled annular groove on each half/part. This would act to self center and float when loaded. Initial location could be achieved by using a loose fitting screw/bolt/pin, just to hold the parts together, such that when loaded this item is clear and free from touching other parts. I had done some design work on the idea and bought some neo magnets to gauge repelling forces (which were surprisingly high), but I then found my holy grail of a CD player, my work priorities changed and I decided not to continue. How would you say your turntable performs in comparison to ready made ones? What did you compare it with?
Many thanks.
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Hi,
TT sound reproduction is a pretty complex issue as it involve too many variable items in the line and the TT is only a part of the the analogue system so not easy to judge I think. I did not own many TT, just a tweaked Thorens TD 160 and before it a cheaper Pioneer that did not made any comparison reference. I sold the Thorens years a go as I think mine is better, but honestly speaking the tweaked Thorens was not too bad as well, but not better then mine. Mine has a better bearing as the Thorens old bearings have a too loosen allowance, the speed control in mine is better, platter wise also I think is better as I like acrylic platter with puck. TA is different issue as now I use a clone of the supatrac 12 inch. I have used a Rega RB 250, a jello SA 750 L 12 inch and some self made clone such as a 12 inch Ref 1 from Schroeder, a Unipivot 12 inch as in the picture. Does it worth to build it? Not so sure as the final cost is not ...lets say too low in my execution. Platter costed alone 400 Euros, bearing was made by my ex company for free under my design, but some material cost was involved. Motor higher cost is the case as I used a old brushless 5 inch floppy drive as motor and a PC feeder to supply the DC 12 volts. I use 3 belts now. Some cost for the lathed parts.
In my opinion make your own TT may worth only if the goal is to have a really top TT so the cost worth the result as a top TT made one has a too high cost. In case the goal is to make a cheap one I think is better to buy a made one.
Plinth is a 2 birtch types, 5 layers glued, I have inserted leads inside 3 layers in a particular position. All the metal parts are decoupled.Floating plate has a sound treatment in the lower part.
Comparing to my friend Denon DP 3000, DD type of TT and using the same cart Denon DL 103, same Pre Phono and as TA the Jelco SA 750 L, mine sound better, it is more detailed and have better controlled bass and the back ground much more silent.
Rgds
Adelmo
Thanks Adelmo.
That's good to know.
I'm using a standard Kenwood KP-9010 with a New old stock Sony XL44L or Sumiko Blue Point Special, Very smooth and fluid. I just find CD's (Cambridge Audio CD1) more easy to live with at the moment.
Maybe it was more obtuse than intended but my comment on magnetic levitation - which I happen to think is a neat way to do things - would not work in my case with a approx 50 kg plinth.
If I was starting from nothing I would consider a system using magnetic levitation. I like the idea of light plinths but the materials to make them are not easily available. I would not know where to begin thinking the REGA fellows have probably found the best way to do it; it is obviously not easy or affordable for the average hobbyist.
The whole engine mount thing started when Nareshbrd brought it up and I asked if he would say what he had found that worked. I do not think he has posted on this topic since. But if one does not read the antecedents of comments it all looks very mysterious.
Golly gee, we have to be professionals now? I am a hobbyist - no pretense at being a professional.
If I was starting from nothing I would consider a system using magnetic levitation. I like the idea of light plinths but the materials to make them are not easily available. I would not know where to begin thinking the REGA fellows have probably found the best way to do it; it is obviously not easy or affordable for the average hobbyist.
The whole engine mount thing started when Nareshbrd brought it up and I asked if he would say what he had found that worked. I do not think he has posted on this topic since. But if one does not read the antecedents of comments it all looks very mysterious.
Golly gee, we have to be professionals now? I am a hobbyist - no pretense at being a professional.
Hi Everyone,
I have some not particularly exciting news concerning my turntable project.
The testing of my bearing principle so far has been inconclusive. My test set-up was located on top of a coffee table which made it very inconvenient for testing. I now have the whole apparatus sitting on top of another piece of furniture that allows me to sit down in front of it. The other problem is that, I don't have a motor driving it. I'll work on that in the next few days.
In the meantime I got side-tracked with my bill of materials. I had to change the dimensions of various turntable components to allow for the availability of the various materials. I got that done and my materials arrived last Friday from McMaster.
Sometime this week my friend is going to write a CNC program to machine the six pockets for the bird shot into each half of the Delrin platter.
I purchased a nice camera so that I will be able to provide good pictures throughout the project.
The attached pictures show the new turntable test set-up and the materials I purchased from McMaster. I guess I'm committed now.
My new camera also takes videos enabling me to post some solid models right off my computer screen.
Sincerely,
Ralf
I have some not particularly exciting news concerning my turntable project.
The testing of my bearing principle so far has been inconclusive. My test set-up was located on top of a coffee table which made it very inconvenient for testing. I now have the whole apparatus sitting on top of another piece of furniture that allows me to sit down in front of it. The other problem is that, I don't have a motor driving it. I'll work on that in the next few days.
In the meantime I got side-tracked with my bill of materials. I had to change the dimensions of various turntable components to allow for the availability of the various materials. I got that done and my materials arrived last Friday from McMaster.
Sometime this week my friend is going to write a CNC program to machine the six pockets for the bird shot into each half of the Delrin platter.
I purchased a nice camera so that I will be able to provide good pictures throughout the project.
The attached pictures show the new turntable test set-up and the materials I purchased from McMaster. I guess I'm committed now.
My new camera also takes videos enabling me to post some solid models right off my computer screen.
Sincerely,
Ralf
