Platter deadning?

[HighFidelityGuy]

Hi,

I've just had a bit of a crazy idea that I wanted to run past all you turntable gurus....

I was thinking about those aluminium platters that are basically an upside down dish shape. They ring pretty bad when you tap them and I know there are various tweaks available to reduce this like stretchy rings etc. But has anyone thought about filling the rear of the dish with something like liquid latex? When solidified this should deaden the platter and still keep it perfectly balanced providing you placed it on a flat surface to dry.

The only issues I can think of are that the latex or similar material may not bond to the metal and therefore peel of when you flip the platter back over. Most platters like this I've seen have holes in them, so you'd have to block those up first. Also it may add an undesirable amount of mass to the platter I suppose.

It would be a very cheap upgrade if it did work as you can buy a bottle of liquid latex for a few quid.

What do you think about this?

Cheers. :)

[hifi_dave]

You could use Plaster of Paris like the original 'Rock'...:scratch:

[DSJR]

I prefer the idea of the wide SRM-Tech platter "rings" which damp the ringy edge, tidy the look of faded and patchy Mazak castings and distribute the added mass evenly around the rim.

Careful choice of mats can do the same job. Dave Cawley's particular choice of Techie mat is as much for the platter as it is record support I think...

[HighFidelityGuy]

I guess anything that can be poured and then sets could work (apart from jelly/Jell-O ;)) but I was thinking more of rubbery substances that don't make any sound then you tap them. Plaster and some resins etc will probably still have some resonant properties. So the platter may still ring a little with them. :)

[HighFidelityGuy]

I prefer the idea of the wide SRM-Tech platter "rings" which damp the ringy edge, tidy the look of faded and patchy Mazak castings and distribute the added mass evenly around the rim.

Careful choice of mats can do the same job. Dave Cawley's particular choice of Techie mat is as much for the platter as it is record support I think...

Do those rubber ring things completely stop the platter from ringing? I've got some on order to try but I thought I'd ask seen as you've obviously used them. :)

Cheers.

EDIT: I should mention the ones I've ordered are the narrow ones, as my platter has strobe marking on the edge like a techie's.

[DSJR]

You should find they'll do 75% of it and the mat the rest.

If you tap a playing record, you'll find most of the energy coming through the speakers is in the bass region, either due to record support or slack in the main bearing in some cases. I'm sure the Mike New bearing upgrade on the Techie must contribute to record/stylus behaviour and not just 'cos it's quieter - the total lack of free-play (just enough to allow it to rotate) and superior support of the rotating spindle must have something to do with the sonic improvement, especially at platter edge.....

[Will]

I've damped a lenco and a 401 and for idler drive turntables its a must

the main benefit is in the treble but gives more clarity in the mid and bass

photo of the lenco using car body damping sheets

[goraman]

There is something here we all use called dynamat,one little peice can deaden any ring.
http://www.dynamat.com/technical_specs_dynamat_xtreme.html

[HighFidelityGuy]

Thanks for the replies.
I had thought about using Dynamat/flashing tape type stuff but I was a bit worried about throwing off the balance as I thought it might be difficult to apply it perfectly symmetrically. If other people have managed it I guess it must be possible.

On the subject of using Dynamat/flashing tape; I've had an email from Dave Clarke on the subject and he has a spare Technics platter that has been thus treated and he's offering to loan it out to Techie users who would like to do some A/B testing. He only asks that you cover the cost of postage. If anyone is interested in doing this just drop me a PM and I'll forward on his email address.

On the subject of Latex; I've done some research and it looks like it wouldn't be suitable for pouring. All the videos I've seen on youtube show it being painted on in multiple layers. So that would take a lot longer but it doesn't make it any less possible. The bit I'm not sure on now is how to make the latex bond to the aluminium. I tried searching for latex glues and found some interesting info on making latex cat suits. :lol: It's amazing what you can find on the web. :eek:

I'll keep investigating and I might try this out to see how well it works. :)

[HighFidelityGuy]

Just to provide a quick update; The damping rings I ordered arrived yesterday but unfortunately they didn't fit in the grooves in my PL-71 platter and just rolled out. So I decided to order some liquid latex to play with. I got a 500ml bottle of fleabay for about £6.25 including from THIS (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=220379547429) seller. I'll let you know how I get on with it. :)