andyr Posted January 27, 2018 Share Posted January 27, 2018 1 hour ago, rockeater said: Won't this just stop the platter from turning, resulting in silence? Which as we all know is golden? Well sure - if you take "opposed" to mean ... one is turning c/wise - the other anti-c/wise! But, if you look at my avatar, you can see "opposed" can also mean ... 180 degrees opposite each other, across the spindle. (Both motors turning c/wise.) Andy Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted January 27, 2018 Author Share Posted January 27, 2018 28 minutes ago, andyr said: Well sure - if you take "opposed" to mean ... one is turning c/wise - the other anti-c/wise! But, if you look at my avatar, you can see "opposed" can also mean ... 180 degrees opposite each other, across the spindle. (Both motors turning c/wise.) Andy I really like this design, I’ve seen a config where there is a heavy idler powered by two motors and the belt runs off that. Of course the first thing for me to do would be eliminate the sub platter but that was a compromise in compactness. Link to comment Share on other sites More sharing options...
andyr Posted January 27, 2018 Share Posted January 27, 2018 53 minutes ago, Mark Alexander Whitehead said: I really like this design, I’ve seen a config where there is a heavy idler powered by two motors and the belt runs off that. Of course the first thing for me to do would be eliminate the sub platter but that was a compromise in compactness. Thank you, Mark - I appreciate that comment from someone who is as capable as you are. It is my 'SkeletaLinn' - as you can guess from its name ... it's an extension of an LP12. I designed - and built - it because I fell in love with a locally made, 12" UP arm and wondered how I could use it with my LP12. I rapidly came to the conclusion that I couldn't (without butchering my beautiful, custom-made plinth! ) - so I moved on to designing something that used Linn parts (so was belt-driven and sprung) but could fit a 12" arm. The extra good thing about having 2 motors with a sprung TT is that it centres the spindle/subplatter (as opposing forces are pulling it in opposite directions). In contrast to an LP12, where there is sideways pressure with the belt on the one motor. Andy Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted January 27, 2018 Author Share Posted January 27, 2018 44 minutes ago, andyr said: Thank you, Mark - I appreciate that comment from someone who is as capable as you are. It is my 'SkeletaLinn' - as you can guess from its name ... it's an extension of an LP12. I designed - and built - it because I fell in love with a locally made, 12" UP arm and wondered how I could use it with my LP12. I rapidly came to the conclusion that I couldn't (without butchering my beautiful, custom-made plinth! ) - so I moved on to designing something that used Linn parts (so was belt-driven and sprung) but could fit a 12" arm. The extra good thing about having 2 motors with a sprung TT is that it centres the spindle/subplatter (as opposing forces are pulling it in opposite directions). In contrast to an LP12, where there is sideways pressure with the belt on the one motor. Andy I’m just a beginner in the turntable world, I have a lot to learn. This forum is a great resource for me so I hope everyone will feel free to let me know where things can be improved. I have access to some nice machines but you know what they say “garbage in, garbage out”.? I agree the two motors balances things out nicely. I really like the idea of symmetry of forces. I’m starting to realize there is quite a large community of DIY audio people in Australia and even in Melbourne, I had no idea. Is there a regular get together? Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted January 27, 2018 Author Share Posted January 27, 2018 On 1/26/2018 at 12:53 PM, kffern said: There is a long running but now dead thread on diyaudio on the parallel tracking bearing arm. I tried to have a closer look at the clearaudio version in a KL showroom and it does look like they use some kind of metal carbide material. kffern What bearings did you use? We’re they very smooth? I do wonder how the Clearaudio guys do things. I think they may be using similar methods. Im thinking the jeweled bearing route may be worth a go, when I do I’ll post my findings here. On thing I’m not too sure on is the dampening aspect of tone arms is there any good write ups? 1 Link to comment Share on other sites More sharing options...
kffern Posted January 27, 2018 Share Posted January 27, 2018 1 hour ago, Mark Alexander Whitehead said: What bearings did you use? We’re they very smooth? I worked my way up from cheap Chinese stuff to abec 7 steel. One of the guys on the thread insisted that play was required but I don't think so. I didn't throw too much money at it. I did consider the xyz mount as you did but building a good carriage was the problem. I still have dreams of having another go but not enough time at the moment. kffern 1 Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted January 28, 2018 Author Share Posted January 28, 2018 11 hours ago, kffern said: I worked my way up from cheap Chinese stuff to abec 7 steel. One of the guys on the thread insisted that play was required but I don't think so. I didn't throw too much money at it. I did consider the xyz mount as you did but building a good carriage was the problem. I still have dreams of having another go but not enough time at the moment. kffern I am happy with the Nylon carrrage the glass rods and carbon shaft do a good job of stiffening the assembly. If I went with Carbide rods it would be even better. If I get the rods I will make a new carriage out of carbon and 3D print a two part mold. I can’t imagine I could get it any stiffer without increasing the size of the components. For some reason I still want the carriage to be a low profile structure. Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted January 31, 2018 Author Share Posted January 31, 2018 On 1/25/2018 at 6:53 PM, Mark Alexander Whitehead said: Hi Everyone, In this tread I will document details of my homemade turn table. As it’s already working I’ll upload pictures and details as interest dictates. Regards Mark Arm tilts to accommodate record change. Link to comment Share on other sites More sharing options...
jazzman53 Posted February 1, 2018 Share Posted February 1, 2018 It seldom happens that I run across a DIY project with this level of innovation and craftsmanship... I'm blown away! 3 Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted February 13, 2018 Author Share Posted February 13, 2018 Acrylic record stand and Turntable Cover MK2. The little bumps on the bottom of the record stand make a huge difference, I made it both ways and the smooth one allowed the records to slide around in a undignified fashion. Link to comment Share on other sites More sharing options...
Mark Alexander Whitehead Posted April 28, 2019 Author Share Posted April 28, 2019 I know it’s just an IKEA Kallax but it’s an improvement over the last stand. Link to comment Share on other sites More sharing options...
Monkeyboi Posted April 29, 2019 Share Posted April 29, 2019 (edited) I'm really impressed with the level of innovation and craftsmanship in this project. Well done. I would love to see it and hear It in operation. Cheers, Alan R. Edited April 29, 2019 by Monkeyboi 1 Link to comment Share on other sites More sharing options...
cyxg66au Posted July 31, 2019 Share Posted July 31, 2019 On 25/01/2018 at 8:04 PM, Mark Alexander Whitehead said: The arm is a short tube of carbon fiber with a M2 Red cartridge. It rides on two 10mm ceramic/stainless bearings that travel on two 6mm glass rods. The details were sorted sovertime with multiple iterations mainly because I keep having new ideas so parts gets scrapped and new things tried. Nothing is precious every idea is ready for verification or the bin. The arm is not completely finished, I know there is room for improvement in the area of friction but it’s very close. very interesting, could you let me know where to buy this arm kit, thanks Link to comment Share on other sites More sharing options...
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