A Copernican View of the Turntable System
Dear Daniel, BTW - there were turntable designers contributing to this thread.Yes....you are a turntable designer and Raul is a tonearm and cartridge designer. Unfortunately you must prove it with a 'pudding'? So far we know that Ralph can design amplifiers and Raul preamps. No 'puddings' yet for turntables, arms or cartridges? Although I don't doubt that dessert may someday eventuate? And I certainly look forward to your turntable debut at CES this year? :-) Cheers Henry |
Dgob, I'm really excited about your experiment because I am familiar with the Mambo (not too different from Raul's Acoustic Signature model) and knowing the way the armboard is connected to the 'plinth', I believe you should experience a marked improvement if you separate it onto spikes? The only caveat is whether it is heavy enough to maintain the stability required? |
My apologies to Dertonarm as I have just seen images of the Apolyt turntable he designed in 1990 (google it) and it is quite stunning and interestingly, has massive independent arm pods. To these eyes it would be a disappointment if it didn't sound as beautiful as it looks? Will the 'new' one be a more affordable version of this Daniel? :-) Cheers Henry |
Halcro, here is our 'table. We've been making it about 10 years. It looks all the part of an Empire, but looks can be deceiving. The photo is from about 2000 or 2001. http://www.atma-sphere.com/products/208.html Dgob, I have a little thought experiment for you. You have the platter on its stand or whatever, and you have the separate arm tower. But we are going to put a vibrator under the arm tower but not the platter, and run it. The question is, will you be able to hear the result? I think you can. That, in a nutshell, is what the issue is. There simply can be no extraneous motion besides that of the arm tracking the LP! **Any** other motion is a coloration. So if the arm tower is able to vibrate or resonate at any slight amount that is different from the platter, you have coloration. Cheesy plinths totally allow for this sort of thing- that is what I have seen over and over- and so getting rid of a cheesy plinth is likely a good idea. But that is simply not the same as having a plinth that is properly engineered! (This is sort of the same argument that because a particular LP is scratched and warped, therefore all CDs are better than all LPs.) And you are experiencing a step towards that, as your platform for your towers is in fact your plinth. Try coupling the platter and the arm more tightly into that platform and see what happens. The more dead you can make the platform, the stiffer you make it, the better the 'table will sound. |
Atmasphere, Thanks for sharing this. It clarifies your point well. I am still left with the issue about theory and practice though. The Acoustic Signature Mambo shares your approach with increased mass and a rigid and directly affixed arm-column. It is simply phenomenal in its performance when well isolated. However, the seperated Technics/arm-column improves on specific areas. Key among these are the scale (depth, width and height) of the sound stage; the air/audible space that exists between performers and the ease with which the entire performance is resolved (leading to smoother sound at higher volumes). I am still not absolutely certain what trade-offs might be happening and so I will explore this fully before determining if what I am hearing is just different or actually 'better'. One thing for certain is that it is a dramatic difference. The questions that remain would therefore (at least for those using pneumatic devices under one component or both to decouple the arm-column/TT) seem to include to what degree and at what specific point or level do disparities in vibration of arm column/TT impair the quality of sound produced. They might also include questions of how much does appropriate VTF compensate for any such disparities. This and - 'most importantly - the obvious difference in performance that I am getting at present are important reasons why I'll continue to experiment with the phenomenon of seperation and decoupling. As part of this, I am considering trying spikes, viscoelastic and pneumatic options under the arm column itself, as I am not wholly convinced that seperation and decoupling "must" involve disparity. Time and my hears will tell and both can only be further assisted by the kind contributions of people such as yourself. |
Dgob, the problem with the Technics is that it does not have a real plinth. It is built for the platter only. If you have the deluxe base, the material that the arm sits on is something quite different from that of the platter, at least that is the case in my friend's MkII. This use of dissimilar materials shows that there was not really a concern for the matter at the time. I would say this is one of the things in 'table theory that has advanced since the Technics was built. So in this case, you have to come up with something- the resolution of modern systems being what it is, you can easily hear the faults in the original 'pseudo plinth' system. That is why there are some fairly ambitious plinth projects out there now for the SP-10. Its a great table, but it needs a plinth to really work. In the case of the Technics (if you will pardon the pun) it does seem that if you can separate the platter (and ditch the original 'pseudo plinth'), pin it to a decent platform and then come up with a decent arm tower, that that would be the most expedient means of creating a proper plinth. I've had the idea of making a massive machined metal sandwich of aluminum, brass and high grade steel, that mounted the platter and had provision for the arm. The sandwich was dissimilar metals so their resonant frequencies would be different and thus self-absorptive, while at the same time maintaining rigidity. If there has been anything about the Technics machines that has ever struck me as goofy, the 'pseudo plinth' is it. I know its similar to a lot of radio station 'tables in that regard, but they *did* pitch it as a high-end consumer machine too. |
Atmasphere, I think what you say about the popular plinths for the Technics seems true to my experience. I know someone who used the SAEC solid metal plinth and who still swears by it. However, shipping costs for that monster from Japan are just too prohibitive: at least for me in the in the current economic climate. I think it is also made predominantly or completely from Aluminium and so there are likely to be resonance problems. However, I'm not too certain if they went along the same route as Acoustic Signature in a mixed metal approach similar to the one you have suggested. I also agree about the most expedient approach and that is precisely (if I follow you correctly) what I and others have been trying to do. The only question is whether instead of pinning it to a platform, using the AT616 provides a suitable alternative. This leaves the question of finding a decent arm tower and the experimentation that Halcro and others seem to be undertaking seems fascinating along these lines to me. I'll try the spikes seated on some industrial absorption material and let you know how that goes. Thanks again |
Dear Henry, if you want this thread to soon get out of hand, the best way is to encourage the idler-, belt- and direct-drive "camps" to start a discussion about what is the "best" drive system for turntables ..... This is a minefield full of personal preferences and highly explosive "sensibilities". Especially so, as each and every of the popular drive principles does have special requirements to the tt-design as a whole. Better leave this alone .... it won't do any good to the Copernican view of the turntable. Cheers, D. |
Hi Dgob - did you try the sp10 with just 3 of the 616's. I realize they probably come in a set of four, but being this exercise focuses on simplicity and isolation does it not make sense to use 3 touch points instead of an extra one under the sp10. 3 will certainly hold it up. Doesn't using 4 make leveling of the TT harder? I use 3 mapleshade brass heavy foot spikes. Henry I believe you use 3 tip toes? Raul did you ever try it with three. Are they only designed to be used with all four? Curious. Thx. Chris |
Halcro, the Empire is equipped with a belt, and an extremely robust drive motor, one that is just about unstoppable. The speed of this machine is so stable that the usual effects of soundstage drift due to speed variation don't seem to exist- its soundstage is a lot like that of reel to reel. I am of the opinion that a robust drive is what is important, more so than the *type* of drive. If it is wimpy it will not matter what kind of drive it is! As a result, if you look at vintage turntables, you will see a following around certain models that were better at getting things right than their competition. All of these machines have very robust drive systems too- the Empire, the Garrard 301, the Technics SP-10. I think this topic was covered elsewhere. |
I use just 3 tiptoes Chris. Rigid de-coupling like spikes are far easier to ensure levelling with 3. With 4 you'd probably find that only 3 are making solid contact. With isolators that use rubber or other 'giving' substances, 4 can often make contact if you want utmost stability ie if you don't want it to tip if you lean on it? |
Halcro, I'm having difficulties with the spiked stand-alone arm column. In my system, it definitely increases the bottom end and lower midrange but I feel it does so excessively. The cost of these elevations seem to be a loss of air/acoustic layering and refinement. However, they gave greater impact on certain percussive instuments and so I need to find a middle ground. I'm still playing with this and will try a mix of the spikes and blue tac approaches to see if I can tune in the necessary accuracy in tone and staging. The fun continues... |
Atmasphere, Thanks again. The funny thing is that the spikes do not offer the level of rigidity that I need. They do however offer grounding. The mix of methods that I am currently using is producing very interesting results but I still need time to explore the accuracy and pros and cons of this (decoupling) approach. I'll give ffedback once I'm certain. |
Dgob, As Lew and Ralph intimate, I believe both turntable and arm pods should be 'coupled' in the same way ie all spikes. I don't believe you should have spikes on the arm pods and pliable footers on the turntable OR vice versa. Assuming you are conforming to this, I still have some doubts about the weight of the aluminium Acoustic Signature arm pod being 'effective' enough on spikes? As Dertonarm and Atmasphere stated, the greater weight applied to the spikes the better? Regardless of all this, it may be that the spikes on the arm pod is giving you a 'better' isolation/coupling and just requires you to become used to the better flow of information. Perhaps a recalibration of the loadings on those familiar cartridges may help? Good luck and please keep us informed of the experiments? |
Hi Henry- you stated and I agree with this concept based on what I am hearing so far. "I believe both turntable and arm pods should be 'coupled' in the same way ie all spikes. I don't believe you should have spikes on the arm pods and pliable footers on the turntable OR vice versa." Both my sp10 and ET armboard are on spikes. However. I am also thinking if you are able to isolate the Platter/motor and armboard "properly" then this should not matter "as much" ? If someones specific combination works in their system/kit it should be evident in what you hear - which is what matters not the concept. This project has provided me with very neutral,distortion free sound - meaning to me no pronounced highs or lows, followed by what I have found to be a very strong desire to... and be able to - turn up the db as Dgob stated in an earlier post and enjoy the music immensely. Isn't this last sentence the PROOF "for me anyway" if certain projects are heading oneself closer toward "shangri la" in this hobby ? My listening since implementation has been at a higher db. I'd like to go higher still but my family doesnt allow it. I need to spend more $$ first isolating my sound rooom better :). Curiosity killed the cat - I put a wanted ad out for those AT616's and someone from Denmark replied and well I now have a set coming to me to try out this theory different feet on TT and armpod/board. I want to hear how it changes things up. Will let u know. Hi Dgob How heavy is the Acoustic Signature arm board that you are using and I am curious what type of center clamp you are using on your sp10 ? My ET 2.5 armboard weighs more than the sp10 itself. The next one will be made of brass and I will ensure it weighs more still. I feel the weight on the spikes is critical for isolation. Dear Thuchan - thank you very much for your cartridge recommendations for my ET 2.5 arm. Cheers Chris |
At low volume levels its not that hard to get a 'table to sound good. Its at high volumes where the rubber hits the road. IMO, the turntable should be unassailable at any volume. I found that once I had sufficient mass and rigidity in the plinth, that that helped, but I also have the 'table perched on an Ultra Resolution Technologies platform, which is one of the best passive platforms I have seen, unfortunately no longer available (and stupidly expensive when they were!). The platform is in turn set up on a Sound Anchors stand that is custom-built to accommodate the platform. In turn the stand is mounted on 3 Aurios-Pro bearings. My point is that it is hard to really know what is the plinth in all this. The only decoupling that occurs is the platform itself and then between the platform and the stand, that is my 'suspension' so to speak. The platform is quite heavy, rigid and inert as it is a sandwich of a special grade of marble, high tensile steel and a military-grade constrained damping layer. Vibration and resonance can be quite insidious in a turntable, so with respect to the anti-vibration platform, the platter and now (in the case of this thread) the arm tower, it is likely that it would be really difficult to go overboard on the whole thing. Points in use under the platter and arm tower, while being mechanical diodes so to speak, are not actually perfect diodes. Like elastomerics, they are more efficient if they are loaded properly! So if the load on them is underpar, they simply will not work so well. Load up that arm tower! Get some mass on it, so the points can do their job. |
Dgob, Decouple all that you want. My point was or would have been that it is perhaps not wise to use very different mounting systems for the tt and arm pod, e.g., spikes on one and AT feet on the other. In that situation, the two separate devices are almost sure to have a different response to external sources of vibration, and, in keeping with my private belief system, we do not want the arm/cartridge and the groove on the LP to be moving in different directions, whilst the stylus tries to do its work. Surely you can see that this might not be a good idea. This reminds me of the old SNL commercial spoof, where the rabbi tries to perform a circumcision in a car driving over a rough road. |
Chris/Halcro, Thanks for your suggestions and I will look into having a heavy arm column produced that may work better with the spiked option. The weight limitations with the Mambo column could be where the problems lie and it'll be fun (and, hopefully, rewarding) to try this out. I'll let you know as soon as I can sort this out. On the issue about both the TT and arm tower being on spikes I think Chris has hit the nail on the head. If you are seeking complete isolation, the different methods are secondary. The question resides in how effective both methods are at controlling resonance and vibration. Henry, if you get a chance to try out the AT616 footers you might be surprised - I was. This also offers you the potential to truly decouple arm-column and TT, which was where I came in, as it were. Lewm, I hope that answers your scenario. |
Atmasphere, Thanks again. I'm going to load up the arm tower as soon as I find a local engineer able to undertake this for me. On frequency extention, I'd hasten to add that I am playing this set up at very high volumes and the quality needs to be heard to be appreciated. So as I said, I think for everything to click into place I will follow your, Chris and Henry's suggestion of building a heavy arm tower. The gains I already have with the current approach to decouplling makes this a more than worthwhile endeavour. Grateful for all your kind suggestions and contributions. |
The arm pod I'm having made is roughly the diameter of the AT 616. When I get my TT back, 3 616's will go beneath the TT and 1 beneath the pod. Hopefully it works out. Before, I had the TT and arm board sitting on different isolation systems: TT on 3 AT-605 footers and arm on Herbie's tenderfoots. Sounded good to me--but maybe I'm hard of hearing. Incidentally, while my TT is in the shop, I've been borrowing a Sony 2251. It sounded woeful at first. I almost gave up and on a lark put the tenderfoots beneath it. Much, much better. Pretty good table overall, in my amateur opinion. @Chris: how did you put spikes beneath your sp10? I'm assuming there's a board in between? That is, the TT sits on the board and the board is on spikes? Or did you thread spikes directly beneath the chassis? |
By the way, in the real world there is no such thing as "complete (mechanical) isolation", which is why I take the position that I take. So when someone claims to have built an 'acoustically dead' plinth, claims of death are exaggerated? Or what does that phrase mean? Really, I don't know. Is it something separate from isolation? If one can create an acoustically dead plinth for one's turntable (as a whole), then mutatis mutandis why couldn't one create separate acoustically dead plinths for TT chassis and tonearm? Does that mitigate the concerns regarding coupling? Or is that a method for coupling? Too many concepts; too little knowledge (on my part). |
Banquo, The point of weighing down the armpod is to couple it to the surface below (which in turn should couple it better to the TT). Putting separate AT616s under the table and the armpod separately negates the effect of adding on the weight to the armpod. At least in the SNL case the rabbi and baby were 'coupled' to the same backseat. Your proposed method suggests the rabbi is better off leaning through a window of another car alongside. If it were me (and it is not), I would suggest putting all four footers below a rigid layer to which both TT and pod are coupled. Your method may work in practice, but it will limit the improvement you get and increase distortion in other ways. First, if you put ONLY the TT on 616s and leave the armpod spiked, AND that is an improvement, it indicates the footers worked. If only the armpod was on footers, and the table were not, and that also improved things, either you have a separate component-led problem to the first one or you have the same problem of resonance coming into everything from below. If your tonearm is resonating, you need to fixt that separately. If it is resonance from below, you want your tonearm and table on the same decoupling platform or the different load presented by armpod and table vis-a-vis their respective isolations will cause weird distortions. |
@Chris: how did you put spikes beneath your sp10? I'm assuming there's a board in between? That is, the TT sits on the board and the board is on spikes? Or did you thread spikes directly beneath the chassis? Hi Banquo - Each of the mapleshade footers have a dimple on top. I am using the bottom half of a two piece system. I put a dab of blue tac on the dimple. The blue tac after setting in overnight is not going anywhere. For me to remove the footers now requires considerable force. You have to pry them off. So no threading was required. I have a picture of the mapleshade footers in this link. http://www.canuckaudiomart.com/view_userimages.php?user_id=5181&image_id=40437 Putting another board between the sp10 defeats the purpose of this to me. It adds one more layer and one more chance of introducing resonance going up to the platter and down. My armboard although not pretty to look at is very functional and will not move. It also holds the bracket that the tonearm cables are connected to. |
There's really no such thing as the complete absence of a plinth. In a typical DD table, the motor is often mounted to a chassis, usually an aluminum enclosure, like the SP10 or Halcro's TT81. And to me that's a plinth already. The best experiment, I think, is take the motor out and place it bare naked on a platform, perhaps supported by tip-toes and might need to be held down by something (which can open another can of worms) because the start-up torque might jerk the the motor out of placement in relationship to the tonearm geometry, unless the casing for the motor is really hefty. Essentially, a comparison between yes-chassis and no-chassis. Naked motor and not so naked motor. Anyone wanna try that? If the naked motor sounds better, then a NO-PLINTHER can wear his/her t-shirt proud. ____ |
T_bone, I suspect the weight will be the issue and I am in the process of addressing this. About the potential effects of this: I am deliberatley aiming to de-couple tt from arm tower. That in short is my experiment and is not (from my limited understanding) adverse to meeting the basic laws of scientific proof. Also, and given the basis to this exercise, I really do not see that by coupling the arm tower to both the Symposium Ultra and its supporting wall shelf in any way "negates the effect of adding on the weight to the armpod." I think that Chris and Atmasphere have already suggested the potential for varied approaches to 'isolation' and to 'damping'. Beyond that, I can only reiterate that the gains already achieved by decoupling the tt (in a manner that I know you appreciate equally) has proven as huge a success as we have previously discussed. The question (and basis to my experiment) is whether further gains are to be had though the method of damping an isolated arm tower. The isolation point seems to me proven in my initial blue tac approach and the results that I obtained there. The damping of the arm tower is where my attention currently lies. To wit, weight. I can offer no greater certainties than that and the obvious results already obtained at this early stage. |
Banqu363, You are not deaf - unless deafness can be spread through ICT! The use of mixed methods (pneumatic and spikes) produces a level of accuracy that I still find startling. Sadly, I do not own a fourth AT616 and so that option is currently not available. Also, I would still need a different arm tower to sit on this as the Mambo column does seem short on mass and might not stabilize - then there's the question of the height that this would raise my tonearm in relation to the tt (but a suitable arm tower could undoubtedly address these factors - if I had a fourth AT616). I look forward to hearing back from you on the results. Good luck |
