There are many on line examples of folks making layered plinths for idler drive decks, this is my first effort. 

My GL55 was really surprising me as regards the good sounds it made, and it seemed fitting to continue the work I detailed here and complete the rebuild with a decent plinth.

Main criteria were :-

1. Use raw materials I could find in house. (I know rationing has ended but old habits...........)

2. Follow guidelines re using mix of materials eg ply and mdf.

3. Small footprint - this deck is an odd size anyway because of the arm at the top layout, so I want to keep it a manageable size.  The 'found' materials dictate size available too.

I had recently dismantled an old tv cabinet and reclaimed some thin ply and mdf boards of suitable sizes.  Managed to get an hour in a wood workshop, and a willing helper (thanks John).  

First step was to cut all wood to size and jigsaw the necessary cut outs from the layers. 

The top layer is the board I was using for the deck while auditioning, I copied the cut out to the second layer, then subsequent layers just had a motor sized cut out.  Some experimentation and re-cutting ended up with the pic below.

Last check to confirm chassis fits without problem.

Cutouts for the arm have been done and I've clamped the layers to allow the holes in the top layer to be drilled right through all layers.  These holes allow me to use threaded rod to line up the layers for glueing.

When Jean says this project should be fun I think he means this bit, where you get to slop glue all over and generally make a mess.  Btw if you do this - put some newspaper down first!  It took a while to clean up after this glue fest.

All layers glued and bolts tightened, then cramps to help the glue do it's work.

  Left overnight, can't wait to get back to it for the next step ...............................more to follow.

Left is the original mounting board for the GL55, and right is the new one.  Now it's time to sand it. :(

If possible use electricity and a good mask!  Getting better, I am still deciding how to finish the plinth so I will rebuild the deck and come back to paint/varnish later.

In order to get the deck fixed firmly to the plinth, I used these plasterboard fixings into the plinth. 

With fixing screw in.  Very solid mounting.

Rewired the motor to enable a plug & socket connector to be used.  When I get to varnish this plinth, I plan to set the cables in grooves in the base, like Jean's.  Now where's that router?

Playing the Monkees Hits with an old cartridge just to warm it up.  Bertie Bassett would like the plinth.

Instead of the Sau2, I am trying out a Linn LVX.  The plastic idler wheel was still very noisy as expected, so for the listening sessions I am using the metal idler from the B55.  The difference between these idlers is night and day, the metal one is so quiet.  First quick impressions - the sound is very clear and image good, with no deck generated noise getting to the speakers, still a little bass light c/w the 75.  I'll experiment with some different mats and feet.

I will spend some time now just listening to a wide selection of LPs, to get the measure of the unit with plinth.  Next time it leaves the den will be for varnish/paint, and any mods I decide it needs for increasing the ease of use.  I'm already thinking about a new arm board and grooves underneath for the cables.  

Update - extended listening revealed three problems with the setup. 

I had gone back to a rubber mat but soon changed to a glass mat with a shelf liner mat on top.  I think the extra weight helps.

I tried various feet (brass, wood etc) with mixed results and ended up with the candle case isolators I had used with the 75.  The weight is really too much for them but nothing else sounded nearly as good.

I had lots of problems with sibilance on certain albums, changing the arm board from ply to mdf sorted it.  I'm not 100% certain it was the material change that did it, as the new board was also fixed more securely to the plinth, so the jury's still out till I test more arm boards.