I finally got around to uploading pictures of my first roller bearing tweak test. Not knowing how much this tweak would do to my system, I felt it was necessary to do the best I could without spending a lot of money. Total cost was about $5 (I already had the rope caulk from previous chassis damping efforts). Source: chrome basting spoons are from Walmart (0.94 ea.), Marbles are from Walmart ($1.99 for about 75 marbles, you pick the smoothest for the project), cork from Ikea ($0.50 for a pack of 12 I think). Rope caulk (weather stripping) from Home Depot - big package for about $3.50

Up front - after tweaking the suspension of my CD player for weeks, I was not expecting a lot of impact over the most recent change from superballs to caulk balls. However, these three roller bearings were one of the most dramatic improvements to my system overall. You owe it to yourself to try this at this price!

Here's my system before the roller bearings moved in:

<img src="http://didnt.doit.wisc.edu/audio/roller_bearings/rollers_player_before_install.jpg">

Note the gray caulk balls resting in hose washers right below the player - that was the last change before moving to the marbles. It sounded better than superballs in that location. Details to that setup: the rack is horribly ringy, but it is very solid and it was cheap. I'll replace it once I make up my mind about what to build). On the rack first (invisble) some foamed packaging material, then a layer of mdf, then a 12" underinflated inner tube, then again mdf sandwiched with a 1/4" plywood sheet (glued together for even better resonance control). On top two 16x8x1.5" paving bricks forming a square platform. On top of that the caulk, the player and on top of the player three more bricks.

This sounded pretty good compared to just setting the player on the innter tube, as I did for months before this setup. 

Then, one day, I had some extra time and decided to build the roller bearings to see if all the praise I have been reading here was for real. I went to wallmart and picked up the spoons. The rest I already had in the house.

Here are my raw materials:

<img src="http://didnt.doit.wisc.edu/audio/roller_bearings/roller_bearing_raw_materials.jpg">

The spoons had to lose the handles first. I started with a dremel and a small cutoff wheel and got the first one off. Tedious, though, and power tools had to come to the rescue and accelerate this part of the job. Off to the garage, where a Makita angle grinder was waiting since it's last use on a Toyota Landcruiser rebuild project <insert Tim Allen grunts here>  Safety glasses, ear plugs (we want to use our ears for music), and sparks were flying for a few minuts. The spoons were then cut to size so that there was no material extending over the rim height at the center. 

Next I had to put caulk under the spoons to create a support structure, as well as reconance damping. Caulk is great for that and after a few minutes of forming the material around the bottoms of the spoons, I had the bases completed:


<img src="http://didnt.doit.wisc.edu/audio/roller_bearings/roller_bearing_base_caulk_rings.jpg">

Now, caulk is really sticky, and I was considering to wrap the bottoms of the spoons in food wrap foil, but decided to use thin cork coasters instead (to be able to move them around easier. I suppose that once I find the proper location for the bearings, I'll remove the cork and use th foil. That way the caulk can couple with the stone surface below much better. Ideally, cauld could go directly on the stone, but it's a mess if you ever change your mind about the location of these spoon cups.

below the final layout - hard to see the details because of the flash, but note the shiny smooth chrome spoon, about 2.5" across, low gradient surface. Hard, smooth and not too steep, which is perfect for a maximum effect of the roller bearings. The marbles I selected were rolling back and forth in that spoon for over 30 seconds before coming to a complete rest. The longer they roll, the less resistance, which is what we are looking for with this device.

<img src="http://didnt.doit.wisc.edu/audio/roller_bearings/roller_bearings_shiny_chrome_dish.jpg">

Below two images of the dish placement with marbles and CD player on top of them. Note the absence of the bricks that used to sit on top of the player. Listening tests showed that the bricks degraded the sound.



<img src="http://didnt.doit.wisc.edu/audio/roller_bearings/rollers_under_player.jpg">

Also note the low clearance. The marbles are about 1/2" or possibly just 10mm. The bottom of the CD player lost the original feet a long time ago, but I still had to search for the best (smoothest and level) spots to position the bearings. I made sure the base was totally level before placing the bearings and CD player on the paving bricks. That was accomplised by positioning the inner tube and paving bricks in the proper relationship. Should be even easier on a shelf that's not as flexible as my metal rack.

<img src="http://didnt.doit.wisc.edu/audio/roller_bearings/roller_bearings_in_use.jpg">

One bearing under the drive mechanism, the other under the power supply, and the third on the far right center to balance the setup on a maximum sized triangle.

A slight push against the buttons on the front of the player start a rocking motion that slowly comes to an end (cables connected in the back do dampen the larger motions). I made sure there was very little tension on the cables in back before playing the first test track.

The impact? I was shking my head in disbelief for the next two hours of test listening. DETAIL and bass like never before. Even passages that in the past sent my maggie bass panels into distortion suddenly came across, at high volume. So it wasn't just the speaker's fault. 

Now I'm off to source some chromed wheel bearings at the local bearing shop (yellow pages, bearings) - for a few bucks more I am going to replace the marbles with a harder material. Tungsten bearings are still over the top for my budget, but I know I will keep experimenting with this for some time. Next up is to put my Foreplay tube amp on rollers!

Check my system listing in the asylum for additional details and tweaks I have done in the past. This tweak, right after moving to a tube pre-amp, is one of the most dramatic positive changes introduced to my system, and it comes at a stage where the rest of the system is already very good. I just didn't expect to hear SO much more after adding three spoons and marbles to my system. Try it - it's cheap and if you have a tool that can cut off the handle of the spoons, it'll take you an hour to hear for yourself!

Happy tweaking!

Peter