Dsa, I think there may be some confusion over the meaning of "pod" in this discussion, but I'll come back to that.
A couple of years ago when I got an SP-10 Mk2A, I started researching plinth design. Initially I cut out a 20" X 18" sheet of 3/4" particle board (not even MDF) so I could mount an arm to enjoy the table while designing and building a proper plinth. I experimented with different mountings, from the Technics bottom pan directly on a shelf to various absorptive materials either under the pan or supporting the particle board frame. I have not liked any springy support and the differences between stiffer support and no support are minimal. But unlike Lew I've not had any problem with the table moving from start-up torque.
Researching plinth design was initially disappointing since there is little info on SP-10s compared to all the rim-drive sites for their Garrards, Thorens, Lencos, etc. One good source for information is the DirectDrive site (see review of plinth materials) but I can't access them now to provide a link. Another is Soundfountain which has already been mentioned. Many great ideas are available from Albert Porter, even if you choose not to buy one of his plinths. I'm sure the OMA slate plinths are excellent but they are costly (at least for my retiree budget).
One other thought for plinth material comes from Townsand Audio, make a mold of the proper plinth and use plaster of paris, possibly including lead shot. Still messy but easier than concrete.
Since I had met Raul and had several discussions with him, I ask for his opinion. Here is where I think there may be some misunderstanding. When Raul says he favors a non-plinth design, my understanding is that he is saying it is not a standard box frame or solid wood plinth. Rather it is similar to what I'm using except even smaller in dimension - just enough wood attached to the platter base to mount the tone arm. Then he places his AT suspension feet underneath the bottom pan of the motor unit.
Many commercial turntables include what is called an arm pod but they are attached to the base mounting the platter/spindle housing in some fashion. I believe this is what Lew is addressing when he talks about the mechanical integrity of the platter/arm mounting. Very few offer an isolated pod for the arm which could simply be picked up by itself because of the lack of a mechanical connection, other than weight. While I'm not an engineer, much of my reading discussed the importance of stability between platter mounting and arm mounting. Given the microscopic undulations of the record groove, the need for such stability makes sense to me if we want to insure the only vibrations picked up come from the stylus in the groove. And even with a very massive separate pod to stabilize the arm, imagine moving it for the small increments required for proper alignment overhang and offset!
Anyway, for a long list of reasons, my proper plinth has not been built yet, but I must say my SP-10 sounds pretty good bolted up to the single 3/4" board.
A couple of years ago when I got an SP-10 Mk2A, I started researching plinth design. Initially I cut out a 20" X 18" sheet of 3/4" particle board (not even MDF) so I could mount an arm to enjoy the table while designing and building a proper plinth. I experimented with different mountings, from the Technics bottom pan directly on a shelf to various absorptive materials either under the pan or supporting the particle board frame. I have not liked any springy support and the differences between stiffer support and no support are minimal. But unlike Lew I've not had any problem with the table moving from start-up torque.
Researching plinth design was initially disappointing since there is little info on SP-10s compared to all the rim-drive sites for their Garrards, Thorens, Lencos, etc. One good source for information is the DirectDrive site (see review of plinth materials) but I can't access them now to provide a link. Another is Soundfountain which has already been mentioned. Many great ideas are available from Albert Porter, even if you choose not to buy one of his plinths. I'm sure the OMA slate plinths are excellent but they are costly (at least for my retiree budget).
One other thought for plinth material comes from Townsand Audio, make a mold of the proper plinth and use plaster of paris, possibly including lead shot. Still messy but easier than concrete.
Since I had met Raul and had several discussions with him, I ask for his opinion. Here is where I think there may be some misunderstanding. When Raul says he favors a non-plinth design, my understanding is that he is saying it is not a standard box frame or solid wood plinth. Rather it is similar to what I'm using except even smaller in dimension - just enough wood attached to the platter base to mount the tone arm. Then he places his AT suspension feet underneath the bottom pan of the motor unit.
Many commercial turntables include what is called an arm pod but they are attached to the base mounting the platter/spindle housing in some fashion. I believe this is what Lew is addressing when he talks about the mechanical integrity of the platter/arm mounting. Very few offer an isolated pod for the arm which could simply be picked up by itself because of the lack of a mechanical connection, other than weight. While I'm not an engineer, much of my reading discussed the importance of stability between platter mounting and arm mounting. Given the microscopic undulations of the record groove, the need for such stability makes sense to me if we want to insure the only vibrations picked up come from the stylus in the groove. And even with a very massive separate pod to stabilize the arm, imagine moving it for the small increments required for proper alignment overhang and offset!
Anyway, for a long list of reasons, my proper plinth has not been built yet, but I must say my SP-10 sounds pretty good bolted up to the single 3/4" board.
