allenh Posted January 23, 2014 Share Posted January 23, 2014 I'm probably missing an obvious one but can anyone think of a direct drive turntable that has a sub chassis in the Ariston, Linn, AR, Pink Triangle mould? I've got a few SL1200 copies that I've used for parts and am thinking about using one of the motor/bearing assemblies as the basis for a little project I have in my head. Problem is I can't think of another example of a suspended direct drive which usually means if no one else has done it it's a bad idea, that's never stopped me before though. The motor/bearing/control unit I have is quite compact. Quote Link to comment Share on other sites More sharing options...
donnelltech Posted January 23, 2014 Share Posted January 23, 2014 My understanding is that the Technics SL 1600, SL 1700, and SL 1800 models are suspended. Quote Link to comment Share on other sites More sharing options...
allenh Posted January 24, 2014 Author Share Posted January 24, 2014 Thanks for the suggestions but those are damped not suspended. I'm looking for something that has a separate sub chassis that the motor/bearing and tonearm are both mounted on which is suspended from the main chassis by springs or similar, Like a Linn LP12 or Ariston RD12 etc. where the main plinth stays still but the motor/platter and arm move up and down. I can't find one so want to try and work out if there is a technical reason why or if it was just a fashion thing, Japan and the US seemed to favour un-suspended direct drive turntables and Europe suspended belt drive, There are obviously examples of the opposite in both directions but I can't find a proper suspended direct drive and I don't want to embark on a project that ultimately won't work. Quote Link to comment Share on other sites More sharing options...
jase Posted January 25, 2014 Share Posted January 25, 2014 I wonder why it seemingly hasn't been done. The main complaint against DD tables is motor noise. And having it suspended should solve that. My guess would be that it wasn't commercially viable to create and engineer such a thing. But even then, if it sounded great, there are plenty of people that would lay down the coin. How odd Quote Link to comment Share on other sites More sharing options...
allenh Posted January 25, 2014 Author Share Posted January 25, 2014 I know, I can't find one and the only suggestion I have had that makes sense is the start up torque of the motor in that it would try and spin the sub chassis but I reckon I can get over that by having softer suspension but at more points than normal. I also need to look at the quality of the bearing in the unit I have as I doubt it's anything special. I've got the motor, electronics and a couple of spare arms that I can't really use on anything else so I'm going to give it a go. Whichever arm I use I will remake so it's 12" rather then 9" just because its possible and no other reason really. I've got plenty of projects to be getting on with but the way the weather is here at the moment I might get to it sooner rather than later. I will make it up in skeleton form and if it works go to the trouble of making a nice plinth for it out of wood, if not well nothing ventured and all that. Quote Link to comment Share on other sites More sharing options...
tco Posted January 27, 2014 Share Posted January 27, 2014 Pioneer P3 : http://audio-database.com/PIONEER-EXCLUSIVE/player/p3-e.html Is that what you're thinking of? Quote Link to comment Share on other sites More sharing options...
allenh Posted January 28, 2014 Author Share Posted January 28, 2014 Thanks No that's not quite it, the arm and motor/platter need to be on the same sub chassis which is then suspended and isolated from any other case parts. I have found one which is the Micro Seiki DD-20 which is just like an Ariston RD12 or Linn LP12 but direct drive rather than belt. Quote Link to comment Share on other sites More sharing options...
bearchuck Posted January 30, 2014 Share Posted January 30, 2014 To get an idea of what allenh is talking about when he says "suspended sub chassis," take a quick gander at the underside of the legendary AR-XA ...http://www.vinylnirvana.com/gallery/ar_new_underside.jpgThat metal T bar? That's the sub chassis. At each of the three ends, there are springs which suspend the sub chassis from the plinth and top plate. Near the "T" intersection you can see where the platter spindle is located, and the tonearm is at the bottom right part of the T bar.There's actually a classic AR print ad that shows a hammer striking the top plate and how the platter / tonearm continue to play records undaunted. I can't find the damn thing now, but it's true: I can give the table a good knock and as long as I don't touch any part of the sub chassis or shake it from side to side, it will continue to play records as if nothing happened.The question is not whether or not you could implement a direct drive motor to a sub chassis, but rather "how will it perform?" They don't really look like much, but those AR-XAs are a marvel of engineering and turntable innovation. They're the foundation upon which Linn, Ariston, Sota and Thorens were built, and Edgar Villchur was a true pioneer. Here's a short interview with Villchur that is a nice overview / history of the AR Turntable. The first most obvious issue is that we're basically talking about coupling the motor directly to the sub chassis. Any vibration or noise from the motor needs to travel somewhere, and while some of that will dissipate via the suspension (springs), I imagine that a good deal of that energy would be transferred through both the platter and the tonearm. Mounting the motor with some damping element should help, as will damping the T-Bar, but I think this is probably the most transparent reason why suspended turntables work better with the motor mounted to the top plate, which has minimal contact with the sub chassis.The point about the "torque of the motor" is valid as well, but I'm not sure it could be addressed simply by loosening or tightening the suspension. Tuning the suspension on one of these tables is tricky business. For example, in the XA, the T-Bar must be properly balanced with a perfect center of gravity - accounting for the tonearm / platter (and your proposed motor addition) - and there must be enough mass for the springs to be properly loaded to 70 - 80% of their static height. Too loose and you'll get a fuller bass sound. Too tight and it will favor the midrange. And if you're center of gravity is off, the sub chassis will be subject to platter torque.On a similar note, lateral movement is a big issue with these turntables. In other words, when you give the sub chassis a push, it should only bounce vertically; yawing from side-to-side is bad. To this point, The belt is actually an important component in dampening the lateral movements of the oscillating suspended mass. Remove this component with your suspended direct-drive turntable and you have yet another hurdle to clear. Obviously what you're proposing can be done; I just think that it's going to be an uphill battle to make the thing sound right. I haven't really taken a look at that Micro Seki DD-20, but I will. I'm interested to see how they did it. Still, I gotta think that the belt-driven suspended turntable has thrived throughout the years because it just gets shit right. It gets out of the way of the music. Attaching a motor to the sub chassis seems to go against everything its founders were trying to do. Quote Link to comment Share on other sites More sharing options...
allenh Posted January 30, 2014 Author Share Posted January 30, 2014 AR-XA yes that's the one I was thinking of as an example for everyone Stateside as most people just give me examples of damped tables rather than proper suspended ones. It's also the one everyone copied, Ariston copied it then Linn copied them etc. etc. The basic design didn't change a lot for years and for as many people to have copied it that have the basic premise of a sprung sub chassis is a good one. I agree having the motor in the sub chassis is an all round bad idea but I'm going to give it a go. I am going with quite a few small sprung suspension points, at least 5 +1 anyway and I am mounting the motor and all the suspension screws through rubber bushes, one for isolation and two as a dampening effect for the suspension. The number of suspension points should also help with removing yaw and the take up of the motor torque. At the moment the motor fits into a large circular plate that then has mounting holes around it's circumference so I am going to mount my suspension units around the circumference of the plate and use them in compression onto a plate below. I'm also going to make the arm I am using 12" so that it moves it as far away from the motor as possible and am going to add a suspension unit (the +1) somewhere along the length of chassis that I will need to add to my circular motor mounting plate which will make up my sub chassis. I'm very versed on setting up suspended turntables as they are my weapon of choice so that gives me a bit of feel for the task but it is still a stab in the dark which is most of the fun of it. Micro Seiki did it but how successful I don't know and I expect their motor was of much greater quality than the one I have to work with. It's a but of a challenge so I will give it a go, I'm either going to end up with something great or crap but it will definitely be unique. Quote Link to comment Share on other sites More sharing options...
allenh Posted February 24, 2014 Author Share Posted February 24, 2014 Well it's built in skeleton form. I got it running last night I need to play around with the strength of the springs a bit but it basically all works mechanically. The platter spins and doesn't try and turn inside out on start up, it all seems very stable and the suspension goes up and down as it should. I put a record on it let it track which it did well but I can't check the audio yet as there is still work to do on the arm. I took some pictures but it was a bit dark so I will try some more when I get home from work. Next jobs are to wire the arm and sort out the counterweight in it, I made a longer arm tube so that it's 12" and that means it needs more weight to allow it to balance. Once I have done that I can see what it sounds like before I look to get the woodworking tools out and make a plinth for it. Quote Link to comment Share on other sites More sharing options...
jase Posted February 24, 2014 Share Posted February 24, 2014 Sweet! Ibcantcwait to see/read the final results Quote Link to comment Share on other sites More sharing options...
Iceberg13 Posted February 26, 2014 Share Posted February 26, 2014 I have a BSR that seems to match exactly what you're describing. A 2260bx to be exacthttp://www.vinylengine.com/turntable_forum/gallery/image.php?mode=medium&album_id=1456&image_id=22731 Quote Link to comment Share on other sites More sharing options...
bearchuck Posted February 26, 2014 Share Posted February 26, 2014 I have a BSR that seems to match exactly what you're describing. A 2260bx to be exact http://www.vinylengine.com/turntable_forum/gallery/image.php?mode=medium&album_id=1456&image_id=22731 Um, nope. Quote Link to comment Share on other sites More sharing options...
allenh Posted February 26, 2014 Author Share Posted February 26, 2014 These are some pictures I took the other night which are not great but hopefully you get the idea. It's amazing how a flash shows up all those finger marks, luckily I wont have to clean it all as in the finished article there will be a wooden plinth surrounding and sandwiching the rectangular plate. Sugar Shane 1 Quote Link to comment Share on other sites More sharing options...
allenh Posted February 27, 2014 Author Share Posted February 27, 2014 Clucking Bell, it only bloody works! I'm playing a record on it now and I'm pleasantly surprised, it's probably mostly down to that fact that the arm is now 12" and has been wired in Cardas cable but still i'm quite chuffed with myself. I never actually expected it to sound nice. Time to get the woodworking tools out and make a nice plinth for it. Quote Link to comment Share on other sites More sharing options...
allenh Posted March 13, 2014 Author Share Posted March 13, 2014 It's pretty much finished so here are some pictures of it in action. I did start to make a top plate for it but decided I'm not good enough at woodwork and have convinced myself to like it the way it is. Quote Link to comment Share on other sites More sharing options...
3arl Posted March 13, 2014 Share Posted March 13, 2014 I'm loving that long-ass tonearm Quote Link to comment Share on other sites More sharing options...
allenh Posted March 13, 2014 Author Share Posted March 13, 2014 Thanks, the arm was quite easy to do, just a bit fiddly. Quote Link to comment Share on other sites More sharing options...
jase Posted March 14, 2014 Share Posted March 14, 2014 Buy a piece of slate and use that as a top plate Quote Link to comment Share on other sites More sharing options...
allenh Posted March 14, 2014 Author Share Posted March 14, 2014 Buy a piece of slate and use that as a top plate Yes it would look nice but machining it is the problem Quote Link to comment Share on other sites More sharing options...
jase Posted March 15, 2014 Share Posted March 15, 2014 Marble or sandstone would be a great look too Quote Link to comment Share on other sites More sharing options...
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