Isolation for my Rega 3

You need a light but rigid base for the Rega.They dont like to sit on a heavy base. I have a wall mounted shelf with a Bright Star Audio Big Rock #4 under my P-25.It works great.I had acoustic feedback until I installed the shelf and bought a rock.I wouldnt use anything heavier than a #4 under the table.Its the perfect size rock for Regas.I got mine at Audio Advisor for $90

This may cost too much for your budget, but items with rotaional vibrations like turntables and CD players improve
very much with bearing isolation devices like Aurios MIB or
Symposium Rollerblocks, cost $300 retail.

If I could, I would wall mount, like David. My Planar 3 is on my equipment rack, sitting on a BrightStar Big Rock. That does a good job of reducing grain. I looked for a cone-foot to couple the plinth to the Big Rock that would make the TT sound a little faster (perhaps some pace lost due to the Big Rock?). The brass, heavy-weight, triple-points from Mapleshade are doing a nice job of that plus cleaning and freeing up the sound in other regards. The regular Mapleshade cones made improvements as well; the big guys are better. Between the Big Rock and equip. rack shelf, I have VibraPods to handle low-freq., hardwood floor-borne vibrations.

I'm pleased, but with all this, I feel like I've taken the merits of my equipment rack out of the picture. The rack is very light and of welded steel. So, in the spirit of simplicity, and also that of not leaving well enough alone, I am going to test a different approach and just put the TT on a high-quality, lightweight shelf that has a vibration control approach more akin to that of my rack. But I should emphasize that my current treatments have really helped.