I like the way my SOTA clamp couples the record to the acrylic platter. It comes with a small rubber washer that goes over the spindle, under the record. The clamp presses down on the periphery of the label, and forces the outer edge of the record into contact with the platter. When I remove the record, I have to break the vacuum between it and the platter. And it's not a vacuum 'table! Does the Maplenoll do something similar?

I don't think the weight of the clamp makes much difference in my case. My SOTA Jewel's platter weighs twelve pounds.

The Maplenoll does the same thing.

I use the SOTA clamp on my SOTA table - the table was designed to incorporate the clamp, IIRC.

I use the Well Tempered reference clamp- which obviously is what my WTT is meant to use. It uses a threaded screw assembly that allows for varying torque as well. It's a bit slow though for clamping and un-clamping. Made of Delrin, it's medium of weight but very hard.

I always figured that having the clamp heavier was a good thing in that it would contribute to inertia and thus pitch stability. Maybe not for suspended 'tables though. I like the look of those outrageously expensive Shun Mook clamps. I still might make one of my own for kicks some time...

Shun Mook Clamp

WTT Clamp

No clamps can be used on the LP 12. I may have to change out my 'table soon. Some day.....

I've read that record clamps, because of the added weight, can add coloration to the music... is there any truth this?

My clamp does change the sound, albeit for the better. The bass becomes deeper and tighter, the mids and highs are clearer, and the "silence between the notes" is more apparent. I suppose these could be construed as colorations. For example, if your bass was already somewhat overdamped.

Quote:
I've read that record clamps, because of the added weight, can add coloration to the music... is there any truth this?

Generally I have found this to be the opposite- it improves the sound whether by having more uniform contact of the record to the platter, less warping obviously, and yet another thing to act as a vibrational sink. Only on a motor that is very small with perhaps an over-sized metal clamp would you get problems. Also a light suspension turntable might have issues too. I can imagine for instance not putting one of those big steel clamps on a Rega P1, but who'd buy a clamp almost as expensive as the whole turntable? Usually a clamp will have a list of compatible 'tables. This one looks very nice indeed for the Rega line and is pretty reasonable. Michell Rega Clamp

This Clearaudio one looks pretty nice too, but specifically mentions it's designed to add weight and thus should be for heavy duty motors only. I like the added weight idea for additional inertia myself; luckily the WTT motor can deal with a lot of it. Any of the 'tables with large outboard motors would be able to accomodate a larger clamp I'd think.Clearaudio-Quadro-Clamp

Good reply, dbowker.

Also, clamps tend to keep their mass concentrated toward the center of the platter, which, to my own sometimes odd eye, would seem to have less of a motor/inertial load on a motor than something like a rim ring - for better or ill.

I also have the Michell clamp and it is lighter than other clamps. To wax rhapsodic...it seems more a damper than a clamp.

Pardon the audio-nerd wording, eh?

A record clamp has a relatively (relative to a platter of similar mass that is) low moment of inertia since the moment is proportionate to the square of the distance from the mass to the rotational axis and, as Buddha's sometimes odd eye correctly notes , the radius of the clamp is much less than that of the platter.

As Doug says, I would therefore expect even a massive clamp to have relatively little effect on speed stability or on motor load, unless of course the bearing is particularly inefficient. It might just cause an issue if the mass of the clamp is very high relative to the platter and the motor has absolutely no torque reserves, however even then probably only during start-up.

Since however all the mass exerts a downward force, regardless of the radius, I would imagine that a high mass clamp would accelerate bearing wear and correspondingly reduce service life. It would also likely be completely incompatible with some bearings such as the air or magnetic bearings found in some more exotic decks.

This logic points in the direction of low-mass clamps that lock to the spindle (i.e. reflex clamps) rather than high-mass designs. The trade-off here is that as well as clamping the record to the platter you are also effectively clamping it to the bearing which is a source of noise, however in most cases the spindle touches the record anyway so this may be moot. My old Roksan had a removable spindle for this very reason and I have always wondered why more turntable designers didn't adopt the practice...

When you tune an LP-12 suspension, you tune it with the platter on upside down so you can check and adjust the belt's riding characteristics, the mat is in place on the upside down platter....with a record of 'average' mass on top of that..and the arm over the platter area.

Then tune the suspension and adjust the centering of the springs..and the belt behaviour. All together. You'd have to throw your clamp of choice on there at the same time. And then stick to it.

At least, that is the way I do it. But the clamp's mass would have to measure in at under 150g, otherwise the suspension is no longer going to be tuned or optimal.

The mitchell clamp is likely at or over that limit 'area' (It's a guess on the mass part, but the suspension is quite critical on a suspended table like a Linn) regarding it's mass. Also, banging away on the suspension every time you put a record on is a bit of a pain. I've done this before, on multiple different turntables, ones with or without a suspension.... I'm not sure I care for it. I like what it does, though. A touch of the effect of 'idler wheel drive' due to the loss of micro transient edging, thus more powerful dynamics. The record DOES go minutely backward on a strong sharp transient. This is over and above any potential damping considerations. The increase in transient expression can and many times is confused with a lowered noise floor, with is not guaranteed by any clamp. But a change in the noise floor overall, in some dimension or type of effect..is virtually guaranteed. the trick is figuring out which is which. This can be considered by attempting to figure out if the effect is dynamic or noise floor related. Obviously it is quite likely that one will confuse one effect with the other.

KBK, wouldn't you say the the LP momentarily "slows down" rather than saying it goes "minutely backward?"

"Minutely backward" would seem to imply that the platter stops and then turns in the opposite direction, then restarts in its original direction...which would be quite wonderous to see!

With the felt mat of the LP 12, It might actually slip backward. And yes, you are right, but..I'm thinking of two cars speeding along, observing one another...and the one appears to 'slip backward' to the other. A comparative thingie. Relativity, Dude! As a point of 'rotational stability'.. it would appear to go backward, to a correctly placed 'rotationally stable' observer. And dammt, you know what I mean.

In the never spoken words my old high school English teacher, who would be horrified to ever hear such coming out of her mouth (horror of horrors), "fuck semantics!"

Kind of like when the wheels on a car look like they are going backwards when the car is going forward on TV? I had always thought that was related to the speed of the wheels as it interacted to the refresh rate of the video.

Errrr..yes!... that's exactly what I meant!

I always thought it was because I was car sick.

Well, thanks to this thread, I now know how to do searches for maplenoll on audiogon. With a minimum of spelling errors.

I am astounded, every time I search a topic on Stereophile, by the diverse and detailed responses.  Here I am looking for information on record clamps and the subject wanders into the arena of vision and filmmaking phenomenon.  For the record the phenomena that KBK and mrlowry describe are commonly referred to as persistence of vision.  However; this is incorrect as we must remember the eye/brain system is not a camera/playback system.

So, here I am four years later and; while I found the arguments for the Maplenoll and Sota Reflex Clamp both compelling; I ended up choosing the J.A. Michell Record Clamp because I was satisfied with its reviews and quality construction, and because I was unwilling to pay two to three times the cost to obtain either the Maplenoll or Sota clamps respectively.  Also, to keep my choice in proper perspective, I should volunteer that I am running a modestly priced Music Hall MMF-2.2 rig.

Thank you, gentlemen!