Plinth-building question

[RKnack]

I just bought a General Electric RD-410-8 record changer on EBay. I need to build a plinth for it, as it was pulled from a console. Right now I am trying to keep the cost down, as I don't have much money, so nice hardwood is out of the question (eventually I'd like to go oak or walnut...)

I happen to have some salvaged laminated countertop material, about 3/4" thick. How well would that work for building a simple, useable plinth? It seems to be fairly dense, so I would think it would work okay to keep vibrations down. And I can always spray-paint it black...

[duficity]

Does the top have formica on it? Anything that you can build up and make as heavy and dense as possible will work better than most plinths that come with cheaper tables. What have you got to lose?

[cats squirrel]

plinths are not about density, or heaviness, they are about how well they cope with vibrations. If the wood has a laminate surface, then construct a plinth from two pieces of this, so that the laminate is on the outside. Do not add a layer of anything soft between them, just very strong glue.

[RKnack]

Does the top have formica on it? Anything that you can build up and make as heavy and dense as possible will work better than most plinths that come with cheaper tables. What have you got to lose?

Yes, it is a formica-type laminate. It was salvaged from a clinic office.

It will more than likely be a box-type plinth, with a shelf around the inside edge to support the springs and for the mounting studs to go through.

[cats squirrel]

as your deck is an idler drive, it is now accepted wisdom that such drives are best mounted without springs. When mounted in cabinets, springs were used in an attempt to reduce the influence of console-bourne vibrations. Now it is out of a console, if you use the springs, all you will do is allow the mechanical parts to vibrate, and you will hear them. If you connect the deck to the plinth without the springs, if the plinth is made of suitable materials, the vibrations will be reduce in amplitude, and the music will be easier to hear.

[RKnack]

What would be the proper way to hook up a power cord to this? It has a 3-wire harness that plugs into the motor circuitry and has female bullet connectors on the other end to hook it into the original console.

[bpbutler]

I assume this is some kind of proprietary connector, not a variety of the "standard" NEMA plug?

http://en.wikipedia.org/wiki/Power_plug#NEMA_5-15_.2815.C2.A0A.2F125.C2.A0V_grounded.29

I'm guessing there are 2 wires hooked to the motor, and a 3rd is ground. Run the 2 motor wires to the hot and neutral of a NEMA plug. If possible, preserve hot and neutral, if they were already identified in your current wiring. The only time I could imagine it would be a problem is if the original has neutral connected to ground on the TT. I don't believe they're supposed to do that, but who knows what they did back when. An ohmmeter will confirm for you if neutral is isolated from ground.

The 3rd wire is almost certainly ground. The principle you're trying to adhere to is that of a single point ground. The idea is all grounds go back to a common point. This way, currents on one wire do not induce noise on a different part of the circuit, and ground loops are eliminated.

You could ground the equipment through the AC cord, but if you do that, you should not ground the TT at your amp. If I was in your situation, I would probably choose to ground at the amp, and just use a 2-wire power plug to the motor. That's how my Dual 1237 is wired.

[RKnack]

Thanks!