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Post by Pinch on Mar 23, 2019 23:36:34 GMT
A good few years ago now, when I first started looking into options for modding and upgrading my 1210s, one of the first things that I came across was the idea of damping the plinth. I read various reports from people who'd used a bitumen based product called Dynamat - intended for damping resonances in cars - and so ordered some. But as soon as I saw it I went right off the idea of putting it inside a turntable; seemed like it would be messy and difficult to work with. I then read reports of it oozing in warmer temperatures, and being a bastard to remove. This last point was important, because I didn't want to do anything that couldn't be easily reversed. So I stashed the Dynamat and moved onto other things. But the idea of damping the plinth stuck around, and so last year I did some more research, and found a few people recommending another product called Sonic Barrier - this is (I think) vinyl based, and comes in 1mm thick self-adhesive sheets. This seemed like a much better option, so I ordered a few sheets from the states. Finally today I had some time install it. Here are the before and after photos:   I decided to try to cover as much of the underside of the top plate as I could - since it's only 1mm thick, I wasn't too worried about the affect it would have on the plinth's geometry, so long as the bakelite insert, which sits in between the top plate and rubber base, was still properly balanced and supported (and with the rubber base back on the extra 1mm is not discernible). And since there are a couple of very large gaps in the insert, there are a few spots where I was able to add an extra layer or two of something chunkier, called dedsheet. I've now reassembled the turntable, but probably won't get around to testing it til tomorrow, since I need to resolder the PSU to the main PCB first. But since I have a few of these decks kicking around, I've at least been able to compare the difference that it's made to tapping on the plinth - the damped one is markedly quieter and less resonant than the vanilla one. Presumably a good thing? Hopefully I'll have a chance to test it properly tomorrow. |
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Post by MartinT on Mar 23, 2019 23:54:38 GMT
That's interesting, Tom, as the 1210 plinth is a sandwich construction designed to reduce resonances. I remember having to completely deconstruct it in order to get the Mike New bearing, base plate and separate regulators into position. Your work should help. I know you have the Oyaide but removing platter resonances is a more important job. I have the Mike New ETP platter which is as dead as a dead thing.
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Post by Pinch on Mar 24, 2019 0:00:42 GMT
Yes the stock platter rings like a bell! I had wondered about the possibly of damping it as well, but I'd be concerned about throwing the balance off. I have an ETP platter also, but use it with the Oyaide, since the ETP doesn't have the strobe dots, and I like a bit of bling  |
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Post by MartinT on Mar 24, 2019 0:06:50 GMT
Tom - try the ETP on its own (without a mat). It couples with LPs very well and sounds good. Better than with a mat in my opinion.
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Post by Pinch on Mar 24, 2019 0:26:34 GMT
I did experiment with it this way, but find I prefer it with a mat (and not just because of the bling). An issue I have is that many of my records are far from flat, and so the dished surface of the Oyaide mats, coupled with a weight, helps the table to get the best out of them.
On your point about the plinth's sandwich construction: A problem is that, as a piece of constrained layer damping, it isn't as effective as it ought to be, because there are too many gaps in the sandwich. That is, there are many spots where there's a lot of free space between the underside of the top plate - the constraining layer - and bakelite insert - the damping layer. The bakelite insert certainly adds mass, but doesn't really damp the plinth. The extra damping is supposed to address this. No idea yet whether it will make a significant difference.
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Post by MartinT on Mar 24, 2019 0:55:59 GMT
Good luck with it, and keep us apprised.
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Post by ChrisB on Mar 24, 2019 5:31:02 GMT
I seem to remember a few people reporting good results from using a Michell clamp over a flat platter. When used as designed with its felt washer, it irons out the warps.
Take care with damping - too much is not a good thing!
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Post by Pinch on Mar 24, 2019 6:34:37 GMT
Thanks, Chris! Clamping is something I've yet to explore.
On the risk of over damping, a consensus seems to be that, with suspended turntables, there's a limit to how much they can take, but for solid plinth tables like the 1210 the more damping the better. All the same, this is why I wanted it to be easily reversible; if it does anything I don't like then removing it will be straightforward - just peels off.
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Post by MartinT on Mar 24, 2019 8:02:13 GMT
I used a Michell clamp very successfully, but the best I used, and still have, is a Stillpoints LPI weight. Very good, but a tad pricy.
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Post by Pinch on Mar 24, 2019 8:25:31 GMT
Yes I've been intrigued by the Stillpoints. I've used a weight in the same weight-range, and didn't really like it, but apparently the Stillpoints has some extra tech built in, so might be expected to have a different effect. But yes, pricey. Of course, Martin, you're done with vinyl now, so yours is going spare  |
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Post by MartinT on Mar 24, 2019 9:12:06 GMT
It may be soon...
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Post by speedysteve on Mar 24, 2019 9:13:23 GMT
I have Stillpoints under my Slate bedded SP-10.
Came with the TT when I got it.
Seen no reason to change them.
Interesting mixture of give / damping and stable support.
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Post by Pinch on Mar 24, 2019 9:32:26 GMT
Interesting. Well, if it does happen then shoot me a PM - you have a few bits I might be interested in |
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Post by MartinT on Mar 24, 2019 9:41:25 GMT
I like the LPI weight but I've never liked Stillpoints elsewhere. I've gone right off spikes and hard coupling - decoupling is the solution for me these days.
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Post by Pinch on Mar 24, 2019 21:41:09 GMT
Up and running again now - initial impressions are good!
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Post by Pinch on Mar 24, 2019 22:26:36 GMT
I should note that before reinstalling the PSU I also added over a kg of mass to the inside of the plinth, which has maybe helped also. Almost finished a playthrough of Wayne Shorter's 'Et Cetera'. There's clearly more midrange and high frequency detail, with no obvious loss of bass, which seems to have cleaned up a bit. Soundstage is more focused. The cartridge also seems to be tracking better - a couple of pops which are usually rather loud are markedly quieter. Presentation seems a bit less laid back, but still nice and open. No immediate impulse to reverse the change |
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Post by julesd68 on Mar 24, 2019 22:31:32 GMT
I seem to remember a few people reporting good results from using a Michell clamp over a flat platter. When used as designed with its felt washer, it irons out the warps. Indeed it does, a very effective piece of design IMO. |
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Post by ChrisB on Mar 24, 2019 22:34:08 GMT
Yep, I've been using them since 1987. I first used it on my AR turntables. Got a Gyro a couple of years later and it was one of the first things I got for the Goldring.
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