Helen Bach
if it ain't Baroque ...
Hello Jules, and welcome. Firstly, I must confess I have 7 or 8 Lenco's, most of their designs! And I have been trying to find ways of dealing with improving them for well over a decade. It is not easy, it is not intuitive in most instances, and it will need a lot of thought and a little time to sort things. Having said that, I have other turntables (belt drives) that I no longer listen to. Lenco's give me what I want, clean sound without distraction, without rude letters from the banks!
As regards materials, there are not many which would be up to the task of dealing with the energy issue. And that really boils down to one thing. Energy cannot be destroyed, just turned into other harmless form, and that really means heat energy.
Materials that convert vibrational energy into heat energy efficiently are mostly obscure or very expensive, or both. We are talking about damping (the exponential loss of amplitude of vibrating objects. With materials that damp well, that energy is mostly converted to heat, but some will be radiated, and quantitatively above the critical frequency. Good daping materials will have a high damping factor, an intrinsic property that has to be measured (like density). And for effective damping, we are looking for a figure around 0.4 (no dimensions). As stated, not many materials have a damping factor of around 0.4, with all metals, most plastics, all ceramics and most wood being much lower that 0.4.
Decent damping materials include some wood ( many ironbarks (Eucalyptus), some ironwoods and Jarrah), but most tropical hardwoods have very little damping, even temperate climate woods are not good in their raw state. Other materials which are excellent are engineered woods, such as Panzerholz and Permali (resinated ply), and composites of polyester resin with granular bentonite clay. Most materials sited in hifi circles are pretty hopeless, especially mdf, ply and slate.
If there were any really good, cheap and readily available material/s, they would be used by turntable manufacturers. There aren't.
One can add damping, but it takes a lot of effort and time and material to accomplish something which a single material should provide. And don't get carried away with (so-called) cld (constrained layer damping). Most plinths purporting to be cld are not anything of the kind, but just multiple layers of disparate or the same material stuck together. This is not cld, but a glulam, short for glued laminate, they are not good at damping. HTH
As regards materials, there are not many which would be up to the task of dealing with the energy issue. And that really boils down to one thing. Energy cannot be destroyed, just turned into other harmless form, and that really means heat energy.
Materials that convert vibrational energy into heat energy efficiently are mostly obscure or very expensive, or both. We are talking about damping (the exponential loss of amplitude of vibrating objects. With materials that damp well, that energy is mostly converted to heat, but some will be radiated, and quantitatively above the critical frequency. Good daping materials will have a high damping factor, an intrinsic property that has to be measured (like density). And for effective damping, we are looking for a figure around 0.4 (no dimensions). As stated, not many materials have a damping factor of around 0.4, with all metals, most plastics, all ceramics and most wood being much lower that 0.4.
Decent damping materials include some wood ( many ironbarks (Eucalyptus), some ironwoods and Jarrah), but most tropical hardwoods have very little damping, even temperate climate woods are not good in their raw state. Other materials which are excellent are engineered woods, such as Panzerholz and Permali (resinated ply), and composites of polyester resin with granular bentonite clay. Most materials sited in hifi circles are pretty hopeless, especially mdf, ply and slate.
If there were any really good, cheap and readily available material/s, they would be used by turntable manufacturers. There aren't.
One can add damping, but it takes a lot of effort and time and material to accomplish something which a single material should provide. And don't get carried away with (so-called) cld (constrained layer damping). Most plinths purporting to be cld are not anything of the kind, but just multiple layers of disparate or the same material stuck together. This is not cld, but a glulam, short for glued laminate, they are not good at damping. HTH
