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LP warp and peripheral clamp

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LP warp and peripheral clamp

Postby bauzace50 » 13 Aug 2005 02:33

There are several LPs in my collection with a mild warp. This can be readily seen when the LP is rotating on the platter. The curious thing is I can actually hear a change of pitch when the arm goes up and down riding the warp (warp wow).
There are a few turntables wich flatten the LP with different means, including vacuum pumps. VPI includes the peripheral clamp on several of its models, notably the TNT HRX.
Does anybody have experience with a PERIPHERAL clamp? I know VPI is not the ony one marketing one, but know not who the others are.
Do peripheral clamps really work? (Mind you, I am not talking about clamps on the label of the LP...my VPI HW-19 MkIII has one).
A user's testimonial will help me make a choice to upgrade my HW-19.
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Outer ring clamp

Postby EdAInWestOC » 13 Aug 2005 03:34

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Postby bauzace50 » 16 Aug 2005 08:07

Ed, Thankyou for your suggestion!
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Postby odell » 16 Aug 2005 09:03

Here's another one that might be worth considering:
http://www.xs4all.nl/~rabruil/ttring.html
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Postby bauzace50 » 16 Aug 2005 13:01

Odel, the website you suggested has GREAT information! Thankyou!
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Postby bauzace50 » 20 Aug 2005 16:56

Odell,
I just ordered one "Outer Ring" from the lab you referred! They seem oriented to excellent customer service, so they agreed to receive one particularly warped LP I have, for testing before-and-after the clamp, just to see if the warp will be flattened for playback. They will do so in addition to taking photographs and some sort of technical testing before-and-after.
On top if this, they let me free to decline the purchase if the clamp does not flatten this particular LP. That's true customer service, and I will purchase, regardless. There are other benefits besides flattening LPs and eliminating warp-wow: flywheel effect, and damping of LP/stylus vibrations. They also assure me of no reports from users, regarding wear on the bearing.
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Postby Audie » 03 Sep 2005 06:27

I have the lighter 550 gram RSR (Record Stabilizing Ring) from Rudolf Bruil of SoundFountain and would not be without it. A heavier RSR would have done a better job of flattening records with more pronounced warp, but would not have been suitable for some of my other turntables. It's what Rudolf calls his Universal RSR.

I mostly use the RSr on a heavy Audiomeca Lurne J4 turntable which employs reflex clamping of the record in conjunction with a centre clamp (Goldmund clamp in my case). This helps to some extent in flattening minot warps, but on many records there still remains a slight warp at the outer edge of the record. The effect of this edge warp on the music is noticeable and occasionally, on very demanding tracks, very annoying.
The RSR removes most or all of the warp, depending on the severity.
My floorstanders employ two 8 inch long- throw bass drivers per side and the effect of the warp is apparent in cone flap (which shortens the life of the roll rurrounds-a problem I've had that the RSR addresses).

Even with Audiophile flat heavy vinyl records the effect of the clamp is to clean up the sound. There is a sure-footed feel to the sound.
The Lurne J4 is a very accomplished table but the RSr benefit is still apparent.

This is a a brief account of the RSR used on the Lurne J4. The story for other turntables will be similar with variations, depending on the type of RSR used. Rudolf is very helpful. I'm sure you will be pleased with your purchase.
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Postby Audie » 03 Sep 2005 06:46

One thing I forgot to mention about the use of the Universal 550 gram RSR when using a cartridge which rides fairly close to the record surface, such as my Van Den Hul modded Koetsu Rosewood:
On some records there remains enough edge warp to cause the cartridge to bottom on the record at the highest point of the warp. This happens only at a few grooves at the outer edge and cause mistracking. When this happens I start a little in from the edge so that the cartridge is clear of the clamp.
I'm sure this would not be a problem with the heavier RSRs.
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Postby bauzace50 » 03 Sep 2005 06:53

Thankyou for sharing your observations! I will review these carefully when mine is actually delivered in a couple of weeks...it is being built on order.
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Postby Audie » 29 Sep 2005 19:10

Re. the occasional problem I was having with my Koetsu Rosewood when used with Rudolf Bruil's lightest Record Stabilising Ring.

On checking my notes, I found that I had lowered the VTF from 2gms to1.8gms, as I had noticed that the Koetsu was riding closer to the record than I thought it should. It appears to perform ok, but I do not think that the body should be touching the stabilising ring with the small record edge warps it encounters. The suspension should allow the cartridge to follow the warp without excessive deformation.

I have to conclude that the suspension of the Koetsu needs replacing, so I shall have to send it off to Mr Van den Hul.
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Postby Audie » 07 Oct 2005 06:43

Hi all

Checked out the Van Den Hul tipped Koetsu rosewood with the Hi Fi News test record and the Shure Audio Obstacle Course ERA 111. The cartridge is fine. Found the lightest optamum VTF was 1.95 grams (checked with accurate scales) and the SMEV Bias dial the same. Tracked very well the highest Band 9 of the Hi Fi News Bias setting and only the highest level 5 of bass brum mistracked on the Shure test record. The Koetsu is an early model, so the results are very good.

The Koetsu has a wider than usual body which does create a problem on a few outer tracks on some records when using my record stabilising ring.
Records where the first track does not start too close to the edge are ok.

To solve the problem I'll figure out the best way to bevel a few millimetres in, of the upper inner surface of the ring.
My RSR was one of Rudilf's early hand assembled units. It's possible that there may be very slight undulations in the inner edge of my RSR which is causing the problem. It could be specific to my Ring only, as I have not heard of the problem from other purchases of the RSR.

I expect the manufactured RSR would not have the same problem.
However, bevelling the inner edge might be a good move, if only to account for manufacturing tolerances. I might pass the suggestion on to Rudolf. Possibly he has already thought of it.
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