Dave, How much does the Resomat weigh, in comparison to the stainless steel platter sheet on the L07D? One of my reasons for not experimenting with the L07D, besides the fact that I adore its sound already, is the fact that the mass of the platter sheet is figured into its servo design. If I were to sub out the platter sheet, I'd look for something of very similar mass.
Vintage DD turntables. Are we living dangerously?
I have just acquired a 32 year old JVC/Victor TT-101 DD turntable after having its lesser brother, the TT-81 for the last year.
TT-101
This is one of the great DD designs made at a time when the giant Japanese electronics companies like Technics, Denon, JVC/Victor and Pioneer could pour millions of dollars into 'flagship' models to 'enhance' their lower range models which often sold in the millions.
Because of their complexity however.......if they malfunction.....parts are 'unobtanium'....and they often cannot be repaired.
TT-101
This is one of the great DD designs made at a time when the giant Japanese electronics companies like Technics, Denon, JVC/Victor and Pioneer could pour millions of dollars into 'flagship' models to 'enhance' their lower range models which often sold in the millions.
Because of their complexity however.......if they malfunction.....parts are 'unobtanium'....and they often cannot be repaired.
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03-16-15: Banquo363 @ the Redline, RP guys on this thread (Banquo, Doron, Lewm, others...) Re: the bearing well lubricant discussions... Recently read the synthetic fluid postings here. Found it ironic as my son just bought a used sports car and sent me a bunch of url's to review. they discuss RP and RL as well. like this one ok, nothing to do with this thread, but the similarities are striking. These guys changing out mineral fluids for synthetic in the gearboxes; sort of like you guys with the thrust pad wells ? Anyway you guys reminded me of them. For SP10MKII owners with worn out thrust pad wells. You can get some here Happy listening |
Fleib, I don't think the record/platter interface is understood as you claim and that's where we differ... If it were....there would not be the plethora of platter materials, shapes and weights nor the cornucopia of platter mats (materials, thicknesses etc). I don't believe there are even two turntable manufactures with identical platter/mat combinations...? And if...as you declare.... The purpose of a mat is to provide a stable surface with a similar impedance of the record,then the majority of turntable and mat manufacturers fail in this endeavour..๐ฑ Some think the best mats are forms of acrylic, methacrylate (Delrin), carbon, or vinyl.And some people DON'T think that.... Some people even think that NO mat is better....and on some platters I have found this to be true... And then, as Lewm points out....some even think that the less contact the record has with a platter...the better๐ If you believe that all these opinions reflect an "understanding" of the record/platter interface....I simply beg to differ...๐ |
Dgarretson, although I've not seen a PD444 in pieces, probably its bearing spindle sides were cut into a shape resembling a helical gear. When the spindle turns, such a gear thread will exert a pumping action on the oil contained in the bearing housing. This pumping pressure will center the spindle (so that a hydraulic film is maintained between spindle and bearing housing), and partially unload the spindle pressure on the thrust-plate (depending on the orientation of the helical cut). With this kind of internal structure, it would be no great surprise for the bearing to be sealed. Other turntables incorporated a similar "Archimedes pump" philosophy. For example, Trio-Kenwood's "DL" motor (employed in the KP-880 and later models) had a herring-bone pattern cut into the spindle sides, again for the purpose of pressurizing the oil inside the bearing housing and centering the spindle. As to why the magnetic route wasn't pursued, for sonic reasons most likely Luxman didn't want full platter levitation, which meant that simpler hydraulic partial levitation was sufficient to protect the thrust-plate from the weight of the platter that they chose to use. kind regards, jonathan |
Halcro, If the record/platter interface isn't yet understood or a matter of opinion, why defer to original options offered for your old table? The fact that there were options implies there is/was no one right solution. Perhaps not, but I think this interface is understood better than it was 35 years ago. Seems to be three schools of thought, damping, impedance matching - preventing reflections back, and coupling or decoupling like Resomat. Admittedly, I didn't consider that one. I suspect platter mass and rotational imperfections might have something to do with preference. Perhaps cart/arm synergy is the biggest factor. Regards, |
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