Nude Turntable Project
Although I would like to have all of the electronics mounted remotely it doesn't seem practical - it sounds to me like many hundreds of dollars and weeks of absence - after I find someone to do it. As far as the rigidity of the base goes it is one piece of pressed steel supporting 7 lbs or so. Not a problem. Gary |
Time to pick-up this thread again as I have made a notable improvement to my nude TT-101. Damping and draining vibrations is one area that all audiophiles are aware of and many try to address in any number of ways. I have previously worked on the vibration problems of the TT-101 in two ways: I put rubber bands around the sides of the tin-can base (an obvious problem area) as well as putting a support (I tried both a brass cone and squash balls) in the center of the bottom of the can and brass cones as feet to a granite slab base. (See earlier entries). But, I knew that I hadnt done near enough to optimize this TT. By the way, all of these new improvements will work on turntables that are plinth-mounted as well. For previous turntables I followed the advice of a poster on another site who recommended using copious amounts of clay to fill-in cavities and cover surfaces and I found it worked but I knew that clay was the wrong material for the tin-can base of the TT-101, so I went looking for a different solution. I decided on 3M Sound Deadening Pads: http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtOXMEMXMtEVuQEcuZgVs6EVs6E666666-- One pad costs $7 and was more than large enough to do the entire TT. They are designed to sound proof cars so are available where car parts are sold I got mine online. I covered more than 60% of the inside of the tin-can including much of the bottom as well as the sides necessarily covering a lot of the air-holes. I left enough of the holes open for air circulation (I had monitored the can for heat and after many hours of operation it was still at room temp so I knew it was not a big problem to cover some of the holes). I did leave the top edge of the can uncovered the area where it mounts to the TT - so that a solid metal-to-metal contact remained and allowed vibrations to drain from the TT. I put a rubber-band back on the outside of that area of the can to damp it. I also covered 90% of the surface area of the cavity below the platter to me this is just a resonating chamber left there for manufacturing reasons and in need of damping see photo: http://s1106.photobucket.com/albums/h373/Garya1/Nude%20Turntable%20and%20DIY%20Arm%20Pod/?action=view¤t=TT-101damping003.jpg I also covered the bottom surface of the TT where it used to sit on the plinth why not. The entire job took me about two hours. The material is very easy to work with and mistakes are easily rectified. I used dinner plates of various sizes as templates and a bowl to hold the TT upside down. A circular mat knife was perfect to cut the material a scissors did well also. My first spin after putting it all back together was Brahms first piano concerto (Rubinstein and Mehta on London) an album that I know well and love. I was floored by the improvement in image solidity and full-volume orchestra clarity. Of course I asked my wife to come in and give me the true story without my bias. After listening to the Brahms as well as Christopher Parkening (a rather long listening session for her) she gave me congratulations and confirmed a significant improvement overall. So, $7 in material and 2 hours of time, I guarantee you will be floored as I was. What are you waiting for. Gary |
I added a second arm to my JVC QL10 (TT101 and JVC QA7045 arm and solid particle board/wood plinth) using a bracket of my design screwed solidly into the plinth, and a Micro-Seiki AX-6G arm-board. As you may know the arm-board attaches to a post on the plinth and is swung into place and tightened down. The new board sits almost an inch above the level of the plinth - it had to swing in over the plinth to achieve proper overhang. This left me with the arm too high. So to maintain VTA I had to raise the platter. That requirement brought this thread to mind. I raised the platter by unbolting the TT from the plinth and supporting the nude TT on three Audio-Technica feet but left it in place in the hole in the plinth. The plinth is on aurios/tip-toes, and both tonearms (epa-100, QA-7045) are solidly mounted to the plinth. So now I have a nude TT101 surrounded by two arms on a heavy wooden plinth. Initial listening tests are very favorable. I was quite skeptical of the nude idea, but I must admit a veil has lifted as have my doubts. I can only surmise that the motor was introducing vibrations to the plinth that were picked up by the tonearm. I was very happy before, I am happier now. I hope the pics make all this a bit clearer: http://s1106.photobucket.com/albums/h373/Garya1/Dual%20Tone-Arms%20Dec%202011/ Thanks to Halcro and Raul. |
Lew, I wasn't baiting you. I agree that each type and indeed each model of TT has advantages and disadvantages. I am ignorant about idler TT's and so rather suspicious of them, but willing to accept that the best of them are truly good. I don't agree that the lp/stylus interface has much effect on a plinth. My thinking is more about motor & contact from shelves & airborne vibrations that get loaded into and radiated as well as reflected from a broad plinth. I think the latest wave of plinthed tables is A: retro styling and B: easy arm mounting. Tomorrow I am going to start a thread on vibrations at the lp/stylus interface (which I have been thinking about) I hope to see you there. |
I have made the move to a fully nude TT with DIY arm-pod, from a semi-nude version and so am resurrecting this excellent thread. Previously, I had my JVC TT-101 turntable supported on sorbothane feet - independent of the plinth, but still sitting in the plinth's cut-out. The tone-arms were mounted to the plinth, which therefore served as a large arm-board. You can see my previous set-up here: http://s1106.photobucket.com/albums/h373/Garya1/Dual%20Tone-Arms%20Dec%202011/ Now I have eliminated the plinth completely and support the turntable on three brass points. The single tone-arm is mounted on a Micro-Seiki copper-alloy armboard which is in turn mounted to 1/2 of a 20lb dumbbell. Both the TT and the pod sit on separate parts of a large sheet of granite. And here is what it looks like now: http://s1106.photobucket.com/albums/h373/Garya1/Nude%20Turntable%20and%20DIY%20Arm%20Pod/ In addition to cutting one end off the dumbbell (close to one end)I had to increase the diameter of the shaft to 1.17 inches from 1.13 inches to properly mount the MS AX-6g arm-board. This was done using 4 layers of aluminum tape (used for hvac ductwork). I also sanded the bottom (rubber coating) flat. All together the pod weighs about 15 pounds. I wanted a heavier dumbbell but the shaft diameter was too large for some and the base was rounded on others. The total cost of the arm-pod was $285 of which $250 was for the arm-board. I used double stick tape to secure the pod and the TT to the granite to maintain geometry. Sound-wise the noise-floor dropped noticeably which sharpened the leading edges of the notes and made it desirable to raise the volume while listening. My wife pro-claimed this to be a marked improvement (unusual for her). I find it to be far more revealing, which is good for good lp's and bad for mediocre ones. I would highly encourage anyone interested in doing this to pursue it. An easy and rewarding change. |
Halcro, Yes, I agree that a cantilever will magnify vibration and it is a new thought for me. Micro Seiki and many other manufacturers have used this approach for decades and this MS arm board is made out of a very heavy copper alloy that will dampen the 'diving board' effect considerably. So perhaps it isn't that much of a problem? The double-stick tape is mostly for holding geometry on a very slippery surface. I could put the base of the pod on 'tip-toes' and use tape under the cups like I did under the turntable. I have designed another pod made from heavy stainless steel that I will show once I've got it together - 3 weeks or so. It will be a straight vertical design so I will have another data point. Last night I put two heavy rubber straps around the lower portion of the table - pictures soon (maybe before you read this). It was a worthwhile change as I noted a loss of 'cupped hands' coloration. I also want to mention that I have changed the mat. It is now a 1lb lead mat from Merrill glued to the bottom of a thick Achromat. Best I've heard. Gary |
Halcro, I added two photos: the rubber strapped turntable and the component rack. The rack is cast iron, stands seven feet tall and is 3 feet wide. It weighs 200 lbs maybe 300. I am considering building a wall shelf and integrating it into the rack at the level where the TT is now. Yet another project. Gary |
Audpulse, I do what I can. My cantilevered arm pod looks somewhat like the arm boards on Halcro's Raven. . I've thought more about taping the pod to the granite slab vs putting it on points. My current thought is that taping it makes it one with the slab from a mass perspective and points will isolate it. I am going to try both but I am betting that the massive approach is preferable - a 40lb arm board seems good to me. Gary |
Halcro, The rubber straps are flat bungee cords - available at home-goods or hardware stores. Yes I clearly hear an improvement with them - that tin can needs dampening. Perhaps it would be better to coat it somehow. My observations on poorly recorded albums is that the better I make my playback system the better I can hear the flaws in the album. I am quicker to chuck bad records now than I was in the past because they are unlistenable. Of course the good albums just open up wonders. As far as plinth/no plinth, Lew and I just exchanged posts on Vinyl Asylum and he easily stated that bad plinths cause problems but that good plinths can be a benefit. My opinion is that good plinths sound better than bad plinths but at least in the case of good DD tables no plinth is even better. Lew also made the point (Lew my apologies for quoting you and especially if I, by some stupidity on my part, misquote you) that idler drive tables require a good plinth and that string/belt drives often don't. That may well be so, but it doesn't say anything good about the vibration issues of idler drives, does it. As I have stated before, somewhere, a plinth is unnecessary and often undesirable because it collects, holds, and returns vibration to the tone-arm and turntable. I hear the loss of this vibration as gain in all things musical - like going to a better turntable. Things improved for me as I went from full plinth to semi-plinth to no plinth. I am not going back. |
Mab33 welcome to the TT101 group. The idea of draining the vibrations from the bearing is quite interesting. It is a simple plastic thrust plate and a steel ball in a cup of oil. I drained and cleaned mine and refilled it with Mobil 1. I don't know if a more sophisticated ball - synthetic ruby or the like - would make an audible difference, but I am going to try it soon. I think that I would want to replace the plastic plate with a brass one before I fitted a draining rod as the plastic might not transmit the vibrations too well. If anyone knows of a brass or copper thrust plate that I can buy I would appreciate it and then I would replace both the plate and the ball. If you are interested in the original plinth I happen to have a spare. I would certainly try the double mat that I am using as it does the job beautifully. |
Halcro, I see all improvements as cumulative. I agree that the shelf can have a huge effect and must be addressed. And it MAY be a good idea to support the TT at the original support ring. But no matter what else you improve, if you don't damp the tin-can you will still have problems. Even if you decide (heaven's forbid) to go back to a plinth even a wonderful slate and unobtanium plinth, you need to damp that can. I would also damp the chamber under the platter. By the way, no matter how high I set the volume I don't get feedback. $7 and two hours and you will be much happier. Gary |
Raul, I was thinking about a paint solution but decided that I had the space to use this 3M product and that it would be even more effective. I have the pneumatic AT footers under my pre-amp and I used to have them under my TT (I also used squash balls at one point)but decided that I didn't want any rubber creating a flexible suspension so I went with the cones. I don't expect them to damp anything but do hope that they will couple the TT to the granite and drain some vibrations from the TT. The platter on the JVC already has a ring of rubber-like material on it from the factory. I was afraid of putting anything additional on the platter for fear of effecting the balance. Your idea of the motor cover is an excellent one and I will gladly borrow it and dampen the motor cover on my TT as well. Thanks. |
I have been experimenting with damping this tin-can for some time now and I believe that with my current approach it is no longer the place where I can wring much improvement. From the lack of anyone saying that they might try it I guess no one sees much benefit in my method. Banquo, I am sorry I came across as dismissive and curt, my bad. What I should have said was that it seemed off topic for me as my point was to address damping the TT directly, not the shelf underneath it. And, although my TT sits on a cast iron book-case that weighs hundreds of lbs and is surrounded by a fairly effective air-borne vibration absorbtion structure I am still trying to improve the quashing of environmental vibrations. In that regard your suggestion was certainly germaine and useful Gary |
Henry, I left open the side vents and around 40 - 50% of the bottom vents. I have monitored the heat on the TT and it is normal. It never gets that hot in my room (central a/c) so there is enough cooling to handle it. As for your feedback blow-out - I look forward to reading the responses before I venture a wild-ass-guess. Gary |
My turntable (JVC TT101) came with a plinth as a QL-10. Now it has no plinth so however you want to parse the language a large support was removed and now the TT sits on its tin-can of a base on cones. So I believe it is plinthless - nude or not. I am surprised Henry's phono pre blew rather than the preamp circuits - to me it would take a huge amount of signal from the cartridge to blow the phono side and with Henry's recollection of having it on MM there should have been enough headroom to hold this - otherwise dropping the needle onto a record will make a big enough boom to damage the phono circuit. |
Banquo, I have the sheet under the platter as Halcro described. I also covered the entire interior of the chassis with the 3m product as I described along with the underside of the rim (which is how I describe the silver ring that the controls are on), and of course 80% of the tin can at the bottom. I couldn't be happier with that work. Another thing that I did more recently is to put steel/neoprene washers between the motor and the chassis. I realized that the chassis is actually a plinth of sorts as the motor and bearing are self-contained and supported by the chassis. So the table isn't really nude after all. The new washers replace a double layer of steel and copper washers that were there. Most TT motors that reside inside a plinth (both idlers and belts) are shock mounted, now mine is too. If anyone wants instructions on how to do this, let me know. Highly recommended. As for your open bearing area, no big deal - I recently reopened mine to measure the ball bearing so I can replace it with a ceramic ball (it is 4mm - considerably smaller than I remembered). I refilled it with Mobil One. I don't think it matters which synthetic oil you chose - any good one will run in a car engine for 10 - 15,000 miles without breaking down so a turntable won't ever effect it. My TT-101 is running better than ever. Starts right up from a long hiatus. Don't ask me why. Makes me smile. |
Banquo, to handle the tt I remove the platter and turn it upside down on a large flat bowl that is covered with a dish towel. The washers are about 5/8" in diameter and 3/32" thick. They will raise your platter a tad by raising the entire motor. That gives you more leeway as to how tight that bearing thrust plate screw must be. Not tightening it too much is rather critical for clearance as well as proper alignment of the motor components. Lewm, the 1/16" neoprene bonded to 1/32" steel do not make for a spongy mount especially if they are torqued down. Your point is quite valid but my ears tell me this is better. Psychoacoustics no doubt but c'est la vie. Anyway the washers that JVC used, being two metals and thin are a pain in the ass. As Banquo found out (and I did too) they tend to get lost in the machine. Gary |
I haven't been on this site for a while and just caught up with Halcro's brave changes. I admire your "out of the box" thinking, Halcro. I could never feel comfortable looking at the electronic guts hanging out of my TT. My TT-101 is now seated on a "SolidSteel WS-5" brand wall shelf - which is bolted to a brick wall. This wall shelf is a heavy steel perimeter frame supporting an mdf shelf which is leveled by 4 spikes into the steel frame. This excellent support - perfectly leveled (plus I did another adjustment to the height of the bearing thrust plate) has solved all of the start-up problems it was having. It starts immediately and runs at exact speed without hesitation at the push of a button - just as it should. The turntable sits on that mdf shelf using it's original steel can resting on 3 perimeter brass heavy points and a 4th heavy point sitting dead center under the can. That 4th point is a drain for the can and is important even though the can is damped. I have discussed at length how the can is a major problem and needs extensive damping. Mine is lined with bitumen damping sheets (about 1/4 - 1/3 of the venting holes remain open) and has a heavy rubber strap around the top where it mounts to the structure of the TT. Even though only a fraction of the ventilation holes remain in use there is no heat build up - the can stays cool to the touch after spinning for hours. I believe that I have reached a stable point and will leave well enough alone. Ella Fitzgerald is scatting in agreement. |
Halcro, I am happy for any (if any) role I played in inspiring your creativity. In our crazy hobby, everything matters and often it is impossible to figure out what does what to our precious sound. Audpulse, Sorry but no pics available on this one. Here is my best info: 1. first why do you want to adjust the thrust plate - is there a problem with how the platter turns? If not then sit back and think about it some more. 2. if you want to go forward keep this in mind: the pressure on the plate is not random, not at all - if you get it wrong the platter either won't turn or it might make it harder for the table to get a grip and get spinning. Which I think might have happened to me. 3. The TT101 has a center screw that is easily visible and accessible from underneath once you remove the bottom can. To do this it is critical that you first remove the platter, then turn the tt upside down onto a bowl that is broad enough to sit stably as you work. 4. The center screw provides the pressure on the thrust plate. It is screwed in to an exact spot - don't forget that. It is also sealed with Loctite or some such sealer which you will need to scrape away and replace when you replace the screw. 5. Once you take out the screw you should replace the oil in the well - about 1/2 ounce will do. I suggest synthetic motor oil. You can wipe it out with a clean cloth. Careful in that there is a loose ball bearing sitting there and you don't want to lose that. 6. Reassembly is just that, but don't forget to seal that screw or your oil will leak out. I hope that is useful to you. Questions? |
Lewm, the fluid was brown and had particulates in it. The bearing looked fine, the plate is soft white plastic so was dented by the bearing but otherwise fine. I do not recommend opening the bearing up unless you have detected a problem. I thought I had made that point in my narrative. But it isn't a real issue if you do it right, and it also enabled me to put rubber/steel grommets between the motor and the frame. All for education and hobby-fun. Gary |
Lewm, I think the belts are a good idea but insufficient. You need the suspenders as well on those pants. By that I mean the sound dampening sheets. On my iPhone I have an app called a Tesla meter which measures stray electrical currents (RFI). I got this to measure what was coming through my TT's can. The results told me that the transformer puts out a notable amount. I don't recall what the situation was with the ground wire at the time as I have used it in multiple configs. As I recall, the tranny faced the tonearm - food for thought. Clearly I should do some clean experiments and have good data to report - in a day or two I should be able to get to it. Banquo, I feel guilty enticing you down the path of changing the oil and subsequently getting bearing-level problems. I experienced the same and that is why I emphasized returning the screw to the exact position in my last write-up. But of course that was too late a warning. Sorry. Gary |
OK, now I am confused and a bit concerned. I used the Tesla meter to measure stray magnetic fields (as the device tells me) and lo and behold the only area that had high readings was at the top of the platter mostly on the right side of the table. Right where the cartridge tracks the record! I repeated the measurements with the table grounded and not grounded, with my lead mat on and off, with the platter spinning and stopped, with the power on and off. I even tried it on a TT-81 that hasn't spun in a year and got similar results! Is this a problem for DD turntables? There is something in the TT itself that emits a notable magnetic field - I would guess it is the motor. I don't know how to address this but I certainly think that the magnetic operation of the cartridge is affected by this and not in a good way. I would really like to hear that someone else has repeated this experiment and what they found. Time to investigate Mu metal and how I can fashion a shield. Gary |
Is no one interested in the magnetic fields concentrated at the normal arc of the cartridge? It would be helpful and interesting if someone with a smartphone would install the Tesla app and repeat my experiment. Is this a problem? Does it effect all DD turntables? I have ordered mu-metal sheets to try and redirect the magnetism away from this area. More on that in a week or so. Gary |
I can't vouch for the app but the phone has a compass in it which has to be a magnetism detector. So if the app tells me that there is a concentration of magnetic field in certain places and if it is consistent in that reading across multiple tests under varying circumstances then I must believe that it is so. Likely the absolute measurements are not to engineering standards but I am not using the numbers only the relative magnitude of the readings at various spots around the TT. I don't know if the strength of the field rises to a problematic level - might be cartridge dependent. I also don't know how a problem would present: noise?, loss of detail or dynamics due to magnetic interference? Maybe I'll be able to fix the situation and maybe I will hear a change. I'm skeptical that I will. Gary |
I received a sheet of mu-metal magnetic shield today and installed it in my TT-101. Here is the Before image showing the interior damped with automobile damping sheets. Here is the After image showing the mu-metal sheet cut into shape and placed over the motor. It is not grounded, nor is the turntable. The result is that the magnetic field has moved away from the tonearm arc area of the platter over to the opposite (left) side of the platter. It is also more intense on the left side than it used to be on the right side but I think that it doesnt matter because it doesnt reach the cartridge. Mu-metal can only shield an area from magnetism, it cannot destroy the field. It is like squeezing a balloon the air just moves to a different area in the balloon. Soundwise, I havent done any blind testing or even playing an album side with it and then playing the same side without it which is how I like to do it. But, I did play a few cuts on a few favorite albums and was (perhaps deluded into) hearing a better audio image and clearer notes and lyrics than I expected. I got that dumb grin on my face that I get when my rig sounds great. An easy tweek that I (almost for sure) believe in. Gary |
Halcro, the can on my tt-101 is heavily damped with bituminous automobile noise suppression sheets, it is also wrapped with a fat rubber band and as I said I use a cone (more like fat cylinders with sharp points) dead center to further drain it. So while it looks primitive compared to the granite clerical collar (but far less primitive than letting it all hang out) it is actually fairly sophisticated. I use a mu metal shield under the platter, covering the motor. |
The cover is grounded by three screws to the frame of the tt. Also, originally there was a ground cable attached to the cover. I have grounded my tt via a new 3 wire pc that replaced the original non-grounded 2 wire line. The new ground-wire is attached to the frame via the circuit-board stand-offs. Also, I highly recommend damping the cover well, including using a footer at the center to drain it. I get zero feedback even when it is too loud to be in the room, and my left speaker is about 2 feet away from the turntable. |
