Turntable Mods - Bolt on - Add on

kach22i · Nov 27, 2009

Simple turntable modifications done so far to an old belt drive Dual plastic body model.

1. Replace the belt with new original stock replacement

2. Hot wire RCA jacks out the back for lead wire upgrade

3. Sorbogel mat by Audioquest

4. Duct Seal (like clay, stays soft) on underside of platter and inside of hollow plinth.

5. Aluminum plate and acrylic plate with aluminum picture posts as legs.

I've already posted most of these mods in the Analog section. However the last one (#5) is a real DIY so I'm posting it here.

Start with $6 Picture Post from Lowes
http://www.lowes.com/lowes/lkn?action=productDetail&productId=264592-37672-121062&lpage=none

Then a $22 sheet of aluminum plate screwed into bottom of TT.

Add the acrylic ($40, have a shop drill the holes - wish I did)

Repair bad solder joint on RCA (if problems caused by flipping unit occur)

It's no Oracle Audio Delphi, but the soundstage is improved, the bass is solid/deep, and dynamic impact & clarity is set at a new level.

EDIT / NOTE: Original TT weight was somewhere less than five pounds if memory serves. Current weight is 31.3 lbs.

I cut off the original squishy rubber feet to do this modification.

kach22i · Nov 27, 2009

Once you have all these little mods done, going back to acoustic and speaker treatments will be warranted.

The pillow prop sets the center stage voices the best they can, considering there is a big TV in between the speakers.

A Bronze bar under the rear spike, and a composite cutting/grinding disk under the front spikes is the best current balance I have come up with. Steel plate below sits on homemade sandboxes.

You may do one change at a time to measure your results. I often find that any change or improvement requires another to balance it out and to get the most out of it.

Bernard · Nov 27, 2009

George, have you tried throwing a blanket over the light box to listen to what kind of difference it makes?

kach22i · Nov 27, 2009

Bernard said:
George, have you tried throwing a blanket over the light box to listen to what kind of difference it makes?

Light box?

You mean the TV?

Yea, I have a heavy wool blanket I like to use. However lately I don't seem to have the need for it. That is to say the pillows are doing the same job, even better to a degree. Plus if using only the bottom large black pillow I can have the TV on (sound off) and change channels.

Try the David Bowie/Brian Eno LP/CD "Low" with some vintage WWII B&W reels from the History Channel. Something about gray skys and battleships are surrealistic together with the Low LP.

Bernard · Nov 27, 2009

kach22i said:
Light box?

You mean the TV?

I'm referring to your "wall of light and sound", per post 14 in your system link.

kach22i · Nov 27, 2009

It's not a light box, it is a wall I built.......on which lights hang. I suspect the lights may add in diffusion, but they are for background lighting effects only.

The wall has layers designed to diffuse sound and to absorb excess bass. The front face is perforated metal followed by a one inch air gap, then a thin layer of finish grade plywood which has drilled holes of various sized at random to allow sound waves in and trap them in the 3-1/2' cavity.

The wood face panel also reverberates because of it's thinness, therefore deflecting and absorbing bass energy.

The wall cavity is filled with batt insulation and the back of the wall is homasote board. Oak trim all around. A heavier wall with traditional materials may have been better, but I wanted to experiment a little.

The wall sits on some bricks and is not secured to anything, it really should be though. It cannot go very far with the TV there bracing it.

I have a large section of acoustic foam between the acoustic wall and my real wall under the stairs. It helps keep the sound (bass included) from going under the wall and upstairs into my wife's ears.

To answer your question; at one time I hung blankets from the top of the wall, but it dampened the high end treble far to much for my liking. My goal was to diffuse the rear wave, not absorb it. I only wanted to trap some of the upper mid bass.

EDIT: Pillow play.........using a bookend bracket.

kach22i · Dec 25, 2009

I added some brass buttons to act as spikes, they helped a lot. Extended the highs, punched up the bass and the midrange is projecting voices better.

http://s184.photobucket.com/albums/x295/kach22i/Stereo/

If you don't want to get stuck trying to level the table with quarters, I suggest you stick with three feet, not four.

I tried placing a large thick washer under one of the legs between the plastic body and aluminum plate, it did not change the levelness and I scratched the post up badly because I failed to put electrical tape on my pliers teeth.

You can see I'm using a quarter above the brass button spike, not an idea situation, but it works.

Latest center-stage (above TV) acoustic treatment: bookend holds it upright
http://s184.photobucket.com/albums/x295/kach22i/Stereo/

Tube60 · Jan 6, 2010

That's really interesting!
I may have to try that on my Project 1.2 cheapie.
Good job!:rocker:

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