A Copernican View of the Turntable System

@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

Dgob & Banquo,
I wish you the best of luck. I may try to do something similar just to see what happens. If I eventually do, I will also try it with a single plate underneath which could be mounted on pneumatic/magnetic isolation footers. As I have repeatedly stated in these fora, I am a BIG fan of adding isolation footers underneath turntables to lower any resonance to very low frequencies. I remain skeptical that I want my arm and my turntable platter on separate axes of isolation. I cannot see how that would be a good thing as it negates everything one learns about speed stability and controlling the tracking of the cartridge in the groove. All this said, I wish you the best of luck and results.