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Dual 1229 Plinth (or how to make sawdust)

Divotdog

Divotdog

"I can fix it Grampa"
I am presently in the process of building a new plinth for Luckyman’s Dual 1229, I have been asked by several members for some measurements and some advise on building one of these, so I thought that I would just share the build with all of you and perhaps it will help a few of you, I also test fit my 622 into this sub chassis and it fit like a glove so my guess is that it will fit several of the Dual models.
This piece was cut using a pattern cutting bit on my router table; it could just as easily be cut with a jig saw. Note for Joe, this took a week as I wanted to make a pattern so I can mass produce these as necessary, the next one will take about 15 minutes to cut out!
Some of the goals for this project:
Joe had a United Audio plinth that he sent me to work from, No offense to anyone out there but these things are junk, so we decided to go with a ¾ inch plywood sub chassis set into a Mahogany plinth, we will hopefully add some mass and eliminate some resonance from the turntable, and of course make it more pleasing to the eye.

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The mounting holes for the suspension springs are 3/4
A: The distance from center to center across the width is 13 5/8 inches
B: The distance from center to center front to back is 11 inches
C: The widest point across the width is 14 5/16
D: The widest point front to back is 11 inches
The outside measurements are 16 by 13 ¾ , This accounts for an ¼ inch dado for the sub chassis to be set into the plinth.

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The bottom side of the sub chassis shows that there has to be a little machine work done here to allow the locks to work correctly, the sub chassis is cut from ¾ inch plywood, these cuts were made with a one inch forstner bit set to 3/8 depth.

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Fernando said:
If you decide to mass produce that sub chassis you may find some takers on this board.
Click to expand...

Yeah, like me! :) I'm probably getting a bit too ahead of myself, as I'm planning to start a DUAL 604 restoration, thought of posting a new help thread, when I saw this. I'd love to get a new base like this for my TT, subcontract someone to make one for me, in fact the whole bottom. ;)
 
cjacek said:
Yeah, like me! :) I'm probably getting a bit too ahead of myself, as I'm planning to start a DUAL 604 restoration, thought of posting a new help thread, when I saw this. I'd love to get a new base like this for my TT, subcontract someone to make one for me, in fact the whole bottom. ;)
Click to expand...
Stay tuned, the whole thing is coming. :yes:
 
Divotdog said:
The sub chassis is Birch plywood, the plinth will be African Mahogany :thmbsp:
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Should be one beautiful table once your done DD.:yes: African Mahogany is on the short list of woods for the TD166 upgrade.

I too will be waiting to see the finished job.:smoke:
 
Question for you. Duals sort of float on their spring suspension on their light united audio bases. In making a heavier mass plinth are you planning to fasten the top deck down hard against the plinth or do you still plan to let it "float". In some ways, I think with a heavier plinth you could have the chance to tighten the TT top down and make any vibrations from motor , platter etc just bleed into the heavier mass base. Is my thinking screwed up here? ( My thinking is often screwed up but that's another story!) Thanks Norm
 
Mel, Looking good! I think this thread is going to draw a lot of attention for
sure! I predict a lot of good looking, good sounding Dual's will spring out of this.
Ever since Seth (No Transistors) did such a great job restoring this turntable,
I've been anxious to make this table look as good as it sounds. I can't wait!

The line starts here......................................................
 
ZebraBlvd said:
Should be one beautiful table once your done DD.:yes: African Mahogany is on the short list of woods for the TD166 upgrade.

I too will be waiting to see the finished job.:smoke:
Click to expand...

That certainly will be a treat!

I built some of our bedroom furniture out of mahogany and would think that some nice ribboned stock would be stunning on any turntable, especially if the birch top gets a black finish; the black hardware really sets off my stuff upstairs.

Keep those pics coming!!
 
Here are the Mahogany pieces rough cut and layed out to determine grain, The front and rear measure 17 3/8 by 4, The sides measure 15 ¾ by 4, This is ¾ of an inch taller than the UA plinth, we do this so that we can set a bottom in the plinth, I found that a bottom improved the sound on my 622.

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The router table set up for a ¼ deep dado 5/8 from the top of the material.

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The router table set up for the dado at the bottom, using the same depth set up. I will cut the bottom piece 1/8 oversize and then cut it to size with a pattern cutting bit using the sub chassis as a pattern, this way both pieces are exactly the same size assuring a square plinth when we are done!

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