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
Screw-down clamps is an evidence of how fool hobbyists can go. To me It's not pleasant to screw and unscrew clamp all the time I want to change record. I have lots of 45's and singles. No screw-down clamp for me plz.
I have been experimenting with the Stillpoints LP1 on my Kuzma XL, which is normally supplied with a heavy screw-down clamp. It definitely changes the sound in the following ways: the overall loudness of the system is lower; there is less apparent 'propulsiveness,' particularly in the upper bass; the midrange does seem more 'pacific.' I retuned my system to accomodate these changes, largely by fiddling with the crossover point and gain of the woofer on my Avantgardes, and adjusting the overall level of the system (i.e., I play it at a higher setting on the line stage). I spoke with Franc re using it in place of the factory clamp and he did recommend his ebony weight. So, in essence, there is no reason, according to the turntable manufacturer, why I have to use a screw down clamp.
I'm liking what the Stillpoint is doing. But I also changed out line stages recently, and that's made a dramatic increase in bass articulation. So, I readjusted everything again. And it sounds terrific. Right now, I'm sticking with the Stillpoints, but that isn't an across the board endorsement for you to go out and buy one.
I have been playing with several record weight for the past year. My house was going through major renovation and I had no toys to play with for 2-yars, so I bought a few record weights and tried them on several friends' systems.

In the arsenal are: VPI stock clamp, DIY African ebony wight, Furutech Tu-812, HRS, and two versions of Indonisian ebony weight ( same manufacture, one is same weight as the Kuzma, the other about 1/2 lb.

We had tried them on VPI and Clearaudio tables. The results are fairly similar. The HRS was the most consistent as it did not take away information, and had an evenly overall improvement and sounded good on all types of music. The Furutech seems to emphasize on the highs and took away some bass, but had a very good sense of realism. The DIY ebony provided some warmth and organic quality to the sound, but completely sucked out of the bass. The Asian ebony, on the other hand, has all the good quality of the African ebony but retains the bass. VPI clamp sounded veiled and lifeless compared to all of these, even on the ScoutMaster Reference.

We had also compared them to the Kuzma XL, and feel that the Asian ebony has an edge over the Kuzma. Both of them are made of "ebony", so maybe from different continents? The Indonisian one sinks to the bottom when put in the water and feel much more dense. My friend had since sold the Kuzma and kept the Indonesian one.

Note that all the previous comparison were done on non-spring-loaded tables. I had just done the comparison last week on my Michell Orbe SE against the stock clamp. I also use a peripheral ring. The additional weight did not affect the speed too much. But the heavier ones like the Furutech and the heavier version of the Indonesian ebony basically pushed the platter all the way down, nulling the spring effect. But it seems to solidify instrument/voice separation. In this regard, the stock clamp performed the worst, as the edge of a singer or instrument seemed a bit fuzzy or "leaky". All the other medium-sized weights solidify and separate the instruments/voices better, but not as good as the heavy weights.

On my table, both the HRS and the lighter weight Chinese ebony performed equally well. I've not spend time focusing on comparing the two against each other yet. I've also not tried the heavier Chinese ebony yet, as I figure it would push my table all the way down like the Furutech.

One note is that with warped LPs, I get a rumble when using all the weights. The only way to get rid of that rumble is to use the clamp to tighten it down to the platter. Because my table is spring-loaded, I had to use the lightest peripheral ring. It helps flatten some lightly warped LPs, but does not on others.

The Indonesian ebony was purchased on eBay. The guy also sells ebony feet and cubes. The prices are fairly reasonable, and they arrive within a week from Hong Kong.

FrankC
I use a French-made Planax PX record clamp which I purchased during the 1980's. Rather than being a screw-down type of clamp, when installing it pressure is applied to a certain point on its circumference, which causes the diameter of the center hole to expand. It is then placed on the spindle, and pressure can be applied to the record in any desired amount. It is then released, causing the diameter of the center hole to contract, resulting in a firm grip on the spindle.

I don't know if anything comparable is being made today, and I haven't compared its sonic effects to those of anything else, but it seems to me to offer all of the advantages of both a weight and a screw-down clamp, and none of the disadvantages of either. I believe it is made of solid nylon, so that its weight is miniscule, yet it can exert any desired amount of pressure on the label area of the record, and it can be installed and removed in an instant.

Regards,
-- Al
Al- I have one like that from the 80's as well. I think, believe it or not, it was branded as a "Monster" product, but I'd have to look.