I thank all the participants on this thread for sharing their knowledge and experience. Sitting on the perch of not being willing to build my own TT, and not being willing to spend ultra-bucks to buy someone else's summum, and being quite happy with what I have, I am very happy to hear a variety of opinions and experience because I am learning a lot from the discourse. I think if EVERYONE took a step back, they might learn something. Because people are coming at this from different perspectives, they seem to be getting their noses bent out of shape. Almost everyone here except Dertonarm is coming at this from the side of what is commercially viable (either because they need to make something commercially viable, or because they need to buy one which is made by someone else). Dertonarm is coming at it from a different angle.
Years ago, I read the Teres Project archives. They were extraordinarily enlightening to me at the time. I found dissenting opinions, and well-meaning hypotheses which turned out to not work, but in the end a lot of openness to challenging the existing ideas in order to create something better. In the end, those better ways were created (and I would suggest Chris Brady and recent Teres model purchasers believe the Teres Project results are still being improved upon) through hypothesis and trial. The results were that through astute selection of materials and drive system, an excellent TT could be built which was less expensive than the otherwise self-declared state-of-the-art. I would assume that subsequent models higher up, which garnered much praise by people with great systems improved upon the first renditions. It is obvious through Chris' assertions here that he believes his new DD system, and perhaps others', improve(s) upon those highly-praised BD TTs). I am sure they do. The fact that they are still being improved upon means that everyone is finding better and better ways to skin the cat. Dertonarm's main point is that the cat is still the cat (unless, of course, it is Schrodinger's cat, in which case, it may not be), and that there must be a 'best way' at some point (assuming that everyone's measure of 'best' is the same).
I think that Dertonarm will not deny, disavow, disagree, or demean anyone's opinion that a given DD motor driving a high-mass platter can sound better than a given belt-drive high-mass platter system. I am pretty sure that what he is saying is that he has not found it to beat his belt-drive high-mass platter and he has found the compromises in the DD method to be greater than the compromises in HIS BD HM system. Dertonarm has, in every thread, refused to comment on what he thinks sounds better (partly because it is beside the point I expect), but consistently appears to be looking for someone to provide technical input or results rather than an opinion or the result of System A having been better than System B (which is not so much a demonstration of physics as a demonstration of implementation). Trying to critique his results as invalid because he still finds compromises in it is also beside the point.
So far, the fault I find in Dertonarm's discourse is the assertion that DD or idler drive would not work with "highest possible platter weight" and using "high inertia for self-stabilized speed." It may be right, it may be wrong. It is, however, not defined nor supported. If there is a mechanical slippage system (slipping belt drive) there is, by definition, a compromise. In my opinion, the PERFECT implementation of a TT would not use mechanical slippage. It would also not depend on electromagnetic slippage. In a perfect system, it would be pure 100% speed-stable drive. I am assuming his assertion is based on his experience that mechanical slippage may be a smaller compromise than building a system of electromagnetic slippage with no mechanical slippage. In any case, let's see the technical reason why such is the case. I, for one, would expect that one could build a very very good DD HM system given enough time and enough resources - though in the end it comes down to motor speed/torque stability and whether that stability is greater than the speed stability offered by a 'clutch' system of thread slippage.
While Dertonarm's conclusions appear to be 'dogmatic' to some, they appear to be the result of trial and experience. His tone may be dry, and that seems to antagonize some people, with somebody now suggesting he has an 'agenda' (similar to the way some people 'have an agenda' with tubes and OTLs, and others with single driver loudspeakers?). I personally do not see 'constant demeaning of dissenting opinions' so much as I see challenges to demonstrate that opinions are backed with technical results. I am sure that if someone could prove that a DD with high mass platter had better speed stability than a thread drive, many would be interested (including Dertonarm). It just happens to be that while some people profess that such a thing is possible and they have heard it with their own ears, someone else thinks it is still a method with less accuracy than is available than through what he has done himself.
I would encourage everyone to look at these discussions the way they might if they had participated in the Teres Project Archives email exchanges. There is nothing wrong with dissenting opinion (and I for one do not see Dertonarm's commentary to demean dissenting opinion), but Dertonarm's whole point is that he is striving to improve upon what exists, not prove that one existing thing is better than another. His question to all is whether anyone can demonstrate that one method is, in a technically definitive way, superior to another.
Years ago, I read the Teres Project archives. They were extraordinarily enlightening to me at the time. I found dissenting opinions, and well-meaning hypotheses which turned out to not work, but in the end a lot of openness to challenging the existing ideas in order to create something better. In the end, those better ways were created (and I would suggest Chris Brady and recent Teres model purchasers believe the Teres Project results are still being improved upon) through hypothesis and trial. The results were that through astute selection of materials and drive system, an excellent TT could be built which was less expensive than the otherwise self-declared state-of-the-art. I would assume that subsequent models higher up, which garnered much praise by people with great systems improved upon the first renditions. It is obvious through Chris' assertions here that he believes his new DD system, and perhaps others', improve(s) upon those highly-praised BD TTs). I am sure they do. The fact that they are still being improved upon means that everyone is finding better and better ways to skin the cat. Dertonarm's main point is that the cat is still the cat (unless, of course, it is Schrodinger's cat, in which case, it may not be), and that there must be a 'best way' at some point (assuming that everyone's measure of 'best' is the same).
I think that Dertonarm will not deny, disavow, disagree, or demean anyone's opinion that a given DD motor driving a high-mass platter can sound better than a given belt-drive high-mass platter system. I am pretty sure that what he is saying is that he has not found it to beat his belt-drive high-mass platter and he has found the compromises in the DD method to be greater than the compromises in HIS BD HM system. Dertonarm has, in every thread, refused to comment on what he thinks sounds better (partly because it is beside the point I expect), but consistently appears to be looking for someone to provide technical input or results rather than an opinion or the result of System A having been better than System B (which is not so much a demonstration of physics as a demonstration of implementation). Trying to critique his results as invalid because he still finds compromises in it is also beside the point.
So far, the fault I find in Dertonarm's discourse is the assertion that DD or idler drive would not work with "highest possible platter weight" and using "high inertia for self-stabilized speed." It may be right, it may be wrong. It is, however, not defined nor supported. If there is a mechanical slippage system (slipping belt drive) there is, by definition, a compromise. In my opinion, the PERFECT implementation of a TT would not use mechanical slippage. It would also not depend on electromagnetic slippage. In a perfect system, it would be pure 100% speed-stable drive. I am assuming his assertion is based on his experience that mechanical slippage may be a smaller compromise than building a system of electromagnetic slippage with no mechanical slippage. In any case, let's see the technical reason why such is the case. I, for one, would expect that one could build a very very good DD HM system given enough time and enough resources - though in the end it comes down to motor speed/torque stability and whether that stability is greater than the speed stability offered by a 'clutch' system of thread slippage.
While Dertonarm's conclusions appear to be 'dogmatic' to some, they appear to be the result of trial and experience. His tone may be dry, and that seems to antagonize some people, with somebody now suggesting he has an 'agenda' (similar to the way some people 'have an agenda' with tubes and OTLs, and others with single driver loudspeakers?). I personally do not see 'constant demeaning of dissenting opinions' so much as I see challenges to demonstrate that opinions are backed with technical results. I am sure that if someone could prove that a DD with high mass platter had better speed stability than a thread drive, many would be interested (including Dertonarm). It just happens to be that while some people profess that such a thing is possible and they have heard it with their own ears, someone else thinks it is still a method with less accuracy than is available than through what he has done himself.
I would encourage everyone to look at these discussions the way they might if they had participated in the Teres Project Archives email exchanges. There is nothing wrong with dissenting opinion (and I for one do not see Dertonarm's commentary to demean dissenting opinion), but Dertonarm's whole point is that he is striving to improve upon what exists, not prove that one existing thing is better than another. His question to all is whether anyone can demonstrate that one method is, in a technically definitive way, superior to another.