Screw-down reflex clamps vs. record weights


Recently we have seen more and more 'record weights' on the market. These are normally lightweight(300-400gr)and simply sit on the record. They do not appear to give priority to bonding the record to the platter.
Two outstanding record weights of this type are the Kuzma Ebony Record Weight and the HiFi Tuning VRO ('vinyl resonance optimiser') - there is a review of this(for those who read German) at www.fairaudio.de.
It appears that these clamps, rather than channelling disc resonances away through the spindle and main bearing and/or optimising contact between the record and the platter surface, seek to absorb them directly (i.e. into the clamp itself).
The Kuzma Ebony is a particularly interesting case since it has been introduced by a company that supplies screw-down reflex clamps as standard on its high-end turntables.
My question is: has anybody had any experience of these clamps - probably 'vinyl resonance tuners' is a more appropriate term - on their turntables as replacements for screw-down reflex clamps? Clearly as a way of dealing with warped or dished records they will not be of much use, but it may be that they do a better job of damping the disc.
I would be particularly interested to hear of experiences involving SME turntables (whose platters incidentally are covered with a bonded layer of 'Isodamp' damping material).
Thanks,
Peter
pgtaylor
I have two clamps: a Clearaudio Twister and an Orsonic DS-200G. I also have two weights: a Clearaudio Statement and an Oyaide STB-MS. On both of my turntables the weights sound obviously better. The clamps create a "gleam" accentuating the upper midrange. The weights are much costlier but much better. I would that it were otherwise: I'd pocket some cash. Empiricism is your friend in this hobby. Try a few for yourself.
Hmm. After posting the above, I decided to take a dose of my own empirical medicine and do another sound-check of my weights and clamps. I hadn't compared them since I added a Minus-K under my rebuilt Lenco, so the landscape might have change, I thought. Indeed. My Oyaide is weight-adjustable from 200g to 440g. My Orsonic clamp weighs 200g. So I reduced the Oyaide to its lowest weight in order to eliminate the sonic differences from mass alone, and focus the differences in mechanisms--spring-loaded spindle clamp v. gravity weight. Of course, the difference in materials remained. Guess what. The Orsonic clamp sounds more open and natural than the Oyaide weight. When I add more weight to the Oyaide, the bass-weight increases and the image becomes somewhat denser, but the presentation becomes less open. Syntax might be on to something. I'll have to investigate further. Just thought I'd pass it along.
The XL mat is some kind of rubberized textile that is bonded to the top of
the platter. As far as what's best, screw-down clamp or weight, I don't
know- certainly, as I indicated above, Kuzma himself doesn't insist on a
screw down clamp for his own product (although sells the ebony weight as
an alternative).
FWIW, the Stillpoints has these little moveable plates on the bottom , facing
the record label, with some sort of resonance absorbing properties, which
are its raison d'etre.
There is a definite sonic difference between the Stillpoints and the factory
clamp- if I had to choose straight up, without adjusting the system as
described in an earlier post, I would probably choose the factory screw
down clamp. If I compensate for the sonic differences as I have by
changing the x-over and woofer gain, as well as overall system gain, and
note the exact settings for repeatability, that would probably be a fairer
'test.'
WRM57, "...the presentation becomes less open." I suggest you listen more closely. Are you hearing more of the fine details of what is recorded versus the sensation of live sound?

From what I have observed, an LP that is not closely bonded to a well-damped platter, will transmit sonic feedback through to the stylus. This will give the impression of an open feel. It is subtle. However, it is really feedback. Like hearing music performed in a large hall.
Redglobe--I know what you mean and it's possible that the openness I'm hearing is illusory. I'll have to listen further. My rebuilt Lenco has a metcrylate mat bonded to the platter, reducing resonance. But that doesn't mean it's been eliminated. On the other hand, the clamp sounds pretty good so far.