making a plinth for a commercial TT


2002-02-06 9:16 pm
I have a pioneer pl640 at home. This is a direct drive one, and I like the method. But....listening (realy listening instead of playing music) made me aware that there is quite a lot of noise going on. This seems to come from the "enclosure" of the TT. I took the whole thing apart, and there was not much. IMHO, using something else instead of plastic and 1mm steel would give a better result so I think I could make something better myself.

Big question, how do you proceed with something like this. I can take out the motor without any trouble, taking the arm out would not be much harder. But then, what measurements are important? Should they be exactly the same or is there any wiggle room? As for materials, something workable like wood?

Will this be a rewarding experiment or not? Can there be anything gained this way? Or do I better go the all way and go for the diy arm also?

1st, make sure the noise is not generated by the motor or the platter bearing (which usually is an integrated assembly with such TTs.) If bearing is noisy, do not put any effort into the unit.

stick with distance platter spindle <-> arm pivot, there is no wiggle within this dimension. You will not love to try out another cartridge and find the slotted holes of the headshell are too short now.
And please keep the tonearm's angular orientation towards the connecting line between spindle and arm pivot, otherwise the tonearm's antiskating will behave not like its scale predicts.

It is a design/beauty question whether you want the tonearm in parallel to plinth edges when tonearm is on its rest.

plinth: birch plywood, as thick as possible, no cavities except where needed. I would go with 2inch/50mm plywood atleast. Beech plywood also is an option, it has higher density but is not damped as well as the birch.

have fun with the sonic improvements. They should be considerable. :)


2002-02-06 9:16 pm
Ok, so the lines I started thinking in the mean time are fine. Thanks for the support. I'll check the motor/bearing. It is indeed one piece. Could not detect any play in them except axially. It will be a nice winter project.

After reading the diy arm thread, I think the ladegaards arm will be included. Looks great, does not require a large machine shop, and so much freedom.