Slate & acryl DD tt

Slate & acryl DD tt

Hi folks, my first serious post here, hope you'll enjoy.

It began with a Dual 701 DD turntable, a nice turntable, but with an arm that is not up to the specs I wanted. The automatics were malfunctioning, so I slaughtered the tt and bought an acrylic platter from Diy Hifi Supply.

EDS1000acryl01.jpg


I was thinking about the plint, should I make a aluminium-ply-mdf-ply-aluminium sandwich like this:?

EDS1000acryl02.jpg



..or go for something different?

EDS1000acryl03.jpg



I went for something different, and since then I have done a lot of thinking, and a little work:

EDS1000acryl04.jpg


The acrylic platter on top of the slate plint illuminated by the midnight sun

Last easter i got a hole in the slate so that the EDS1000 motor would fit in.

EDS1000acryl18.jpg



Before that I had installed the power supply and speed selector / pitch control in a box:

EDS1000acryl06.jpg



The turntable with the motor and platter installed:

EDS1000acryl19.jpg



..and with a couple of arm boards temporarily placed on top:

EDS1000acryl23.jpg



I nice member of this forum saw the picture above on a Norwegian forum, and offered to make a couple of acrylic arm boards for me:

EDS1000acryl27.jpg



For this turntable the arm(s) have to be DIY as well, I am going for a Ladegaard tangential on the left arm board, and a 12" Schröder copy on the right arm board.

But I do not have enough patience to wait for the arms to be finished, so one of my temporar arm boards have to do as a base for my SME 3009/S2 Impr. for so long.

EDS1000acryl29.jpg



Not willing to make holes in the stone for the arm screen under the base, I had to do a little modification to the arm:

EDS1000acryl30.jpg



The left arm board is mounted to the stone with brass standoff/legs:

EDS1000acryl32.jpg



The right one is only standing on its legs, but they are shinyer than the other ones:

EDS1000acryl33.jpg



And of course there's something that simply does not fit in, and therefore has to go:

EDS1000acryl34.jpg



I am thinking about a motor cover made of black transparent acryl to replace this wooden thing.

The turntable plays with a Shure M75ED 2 with a Jico SAS needle to plow the grooves, and sounds really promishing.

Kind regards
Trond Kjetil
 
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That is some beautiful work, Trond. Everything has such eye-pleasing style and at the same time well-engineered.

I have been thinking of a similar project for some time but never got started. I would always think of too many problems and not enough solutions.

Are you using the bearings from the Dual 701? How did you mount the motor and bearing to the slate plinth? I'd love to see a few pic's of the underneath.

Great work & thanks for sharing!
 
Thank you, bulgin and Iain :)

I am using the bearing from the 701, haven't even thought of using another. The motor/bearing (EDS1000) is of very good quality, and it has less of the typical "DD sound" that many quarts-controlled DD turntables are drabbed with.
The EDS1000 motor is servo controlled, with hall elements as "commutators" as far as I have understood it. That means a very smooth rotation.

I will post pictures with details from the underside soon. The motor will be boltet to the slate plinth, I just have to enlarge the grooves that the bolts shall sit in.

Kind Regards

Trond Kjetil
 
The slate improved the sound compared to the original Dual 701. Dual 701 is not a bad design, but it's arm could be better, somewhat overengineered to my liking.

I was not very satisfied with the stroboscope light, because I wanted the stroboscope to be visible during record playing. The stroboscope is printed at the underside of the acrylic platter, and with the light emitting diodes under the printing, the stroboscope was only visible without a record on the platter.

I did use this circuit for the stroboscope light:

An externally hosted image should be here but it was not working when we last tested it.


I replaced the leds with a brighter one taken from a broken computer mouse and put a couple of zeners in the circuit:

An externally hosted image should be here but it was not working when we last tested it.


The result was a much brighter and sharper blinking, so that the stroboscope got clearer and sharper. I placed the led behind the platter, angled slightly upwards, and now I can see the stroboscope clearly through the edge of the platter.

An externally hosted image should be here but it was not working when we last tested it.
 
The mass of the platter is 2.4 kg, together with the rotor of the motor the total should be around 4 kg.

The platter from above, with flash:

An externally hosted image should be here but it was not working when we last tested it.


The markings on the underside of the platter should be clear enough ;)

An externally hosted image should be here but it was not working when we last tested it.


The motor and the spindle on top. Also a picture of the motor from above:

An externally hosted image should be here but it was not working when we last tested it.


The led behind the platter:

An externally hosted image should be here but it was not working when we last tested it.


And here are some of the parts for the arm, brass and cocombole:

An externally hosted image should be here but it was not working when we last tested it.
 
0.5Kg on 4Kg - 12% - 18dB - it's a significant difference, but not a show stopper. Extra mass lowers resonant frequencies, adds momentum for stable spin, yes?

Trondkj,
It looks like you machined a "spindle extender" piece to accept the platter. The photo shows a single set screw. How did you arrange the set screw(s) to ensure that the platter is mounted on-center to the motor axis?

Any extra mass that is off-center is bad right?

This should show up as wow&flutter or a slight modulation of the recorded signal producing a frequency smearing in an FFT analysis. Do you have a test record to make some measurements?
 
I for some reason can't see the images. I even try it on a different browser. No luck. :-( I really want to see the pictures as I have several DD motors waiting to be mounted on plinths separate from the drive electronics. Whatever is in the pictures, I am sure they look really cool.
 
It's too bad that I can't see those pictures posted. I came to this thread too late. :(

I found a picture the OP posted on the Lenco Heaven site that's really intriguing. The acrylic platter replaces the stock metal platter on top of the Dual EDS-1000 motor from the 701. I wonder of the modifier used an adaptor to fit the acrylic platter over the original spindle.


Tonearm10.jpg