Platter changes

[BigE]

Years ago, I removed the rubber rings on the platter in favour of a sorbothane mat.

Now, I've replaced the sorbothane mat with this acrylic mat (like oracle):

http://cgi.ebay.co.uk/XTM1-MATT-BLACK-A ... 19bf4f92bb

and a clearaudio twister clamp. I have some damping rings coming that go around the platter.

I've been told that it is best to actually glue the mat to the platter, I'm going to try vinyl double sided tape on the outer ring to hold down the mat. It will be cut to cover the entire outer platter.

But before doing that, I want to fill the empty rings.

Up for contenders is Duct seal -- a heavy pliable compound with a specific gravity of 21 vs DAP Butyl-flex -- a flexible adhesive caulk with a specific gravity of 1.4. FWIW, acrylic has a SG of 1.4 as well.

What do you folks think of these modifications? Sacrilege? Which filler, duct seal or butyl rubber caulking do you think would be better?

[BigE]

OK, I'll do that.

I'm just sayin' those items are what I am currently using.

[Alec124c41]

Years ago I bought a Platter Matter 1/4" soft rubber mat that was supposed to be the latest and greatest. It gave me muddy sound.
Last year I bought a turntable, and someone had glued one of these to the platter. It still sucked, and gave me a hard time getting it off.
What I'm saying is, don't glue anything to your platter unless you are very sure it is what you want. And try several other materials for comparison. A couple of pieces of double-sided tape would be acceptable.

Cheers,
Alec

[BigE]

Alec,

What I am thinking about implementing with the platter is constrained layer damping. According to my research a very thin visco-elastic layer between two part of the structure can decrease transmission of vibration a significant amount.

I believe the tweak of putting paper between inner platter and outer ring has it's physics in CLD.

CLD is often implemented by clamping, so my clamp might just do well enough for that. Using adhesives is supposed to decrease the effectiveness of CLD. I was originally going to cover the outer ring with two sided vinyl tape, but it is crazy sticky. I'd need to use a solvent to remove it.

Anyway, what I did today was stuff duct seal into the channels left by pulling out the rubber rings. I can imagine that the rings did provide some damping to the platter, so putting something in there would be a good idea.

That change was remarkable. It was like going up a level in the TT foodchain (diminishing returns in operation). The sound got much more body, without being bloated. The guitars on Passion Grace and Fire, McClaughlin, dimeola and delucia had body, they did not sound like disconnected strings.

Anyway, next week, I will try a sheet of acetate or plastic or inner liner under my acrylic mat, and clamped. That will be my implementation of CLD without adhesives. Adhesives are supposed to lower the effectiveness of CLD.

I will also try different materials between platter and ring. This could be the ideal location to implement CLD, as the ring itself can apply a lot of pressure.

I'll post my results.

Duct seal is $2.50 at the stockyards Home depot (rona and CT don't carry it). It is in rack 27-117. VERY HARD TO FIND. It took three associates 20 minutes to locate it.... The trick to using it is to roll out a long bead, stuff it in, and make sure it is not proud of the surface of the platter. I used an exacto blade to scrape it flat.

VERY happy with the result.

[BigE]

tried two different acetates between mat and platter. It killed the life in the music, and sounded congested. There was poorer delineation between instruments. Reverb trails were not as clear of spacious.

It already sounds good, but maybe it could sound better still?

Next up, ground loops?