What Record Clamp for LP12?

I would not use a clamp with the lp-12. As mentioned you can stress the bearing and damage it. The table was not designed to be used with a clamp. If you are looking for a cheap upgrade I would get the Extreme phono donut mat. Definitely more sense of drive and immediacy without affecting the tonal balance. Also, consider taking off the bottom board and using 3M poly feet (can get at Target) to stick in the corners. When removing the bottom board I noticed a greated sense of depth.

I would like to say that all tables don`t sound better with
clamp.All clamp do not sound great,some make the music
sound bad.(IMO)

None... The bearing and suspension were not designed to include it. I've been an LP12 owner since 1982. LOL

Happy (unconstrained) Listening!

I also have the Goldmund acrylic platter. I've been through a number of clamps and damage to the suspension has always bee a concern for me. I finally settled on the little Clearaudio clamp. It's only about $20 and is quite flat, so fits under the dust cover. It stays put via friction and works well. I would say it's not a night and day difference, but for me, no clamp on the LP12 ever has been. Still, I find it increases the articulation and immediacy enough to be well worth the low price.

The LP12 wasn't designed to be used with a clamp.

However, if you're feeling adventurous, J.A. Michell make a clamp that sits very lightly on the table because it tightens with a collet. Some people use this with their LP12 and get what they consider to be good results.