To Clamp or not to Clamp, THAT is the question!

I've yet to find a turntable that hasn't benefited from some sort of a clamp or weight. It does need to be the right one for the platter, though. A heavy weight will work well on most direct drives. Lighter clamps work best on belt drives with springy suspensions. I have a featherweight plastic clamp that even works on a B&O although I rarely use it. My B&O turntable is for convenience, not super-duper sound quality. I don't want to fart around with a clamp. Instead, I want to put on a record and press Play.

 

are you serious? which record you know is as flat as a platter ? no record is supported by a platter, no record regardless of how you treat or store it is perfectly flat so parts of the record will as it rotates be off the platter. with arm and needle tracking at approx. 1g I can't see the need for support. When I spoke to the Michell rep she told me the washer was there to insulate the record from whatever rumble there might be attributable to the platter. So I ordered a spare. At the end of he day it all boils down to what your ears can discern.

 

If you're on the fence about getting a clamp or a weight, I'll say it again, I would try a hockey puck. It's a very cheap method to determine if a clamp could help your system. Use a 15/64" drill bit and don't go entirely through the puck. This way you can use it as a clamp and not just a weight. I am satisfied with my puck and don't see a current need to buy a more expensive clamp, and it has improved sound quality on my setup. The sound is tighter with more separation. It may not be as pretty as some of the shiny weights out there, but you'll save a bunch of money and still get good performance.

 

I use the clamp that came with my Music Hall MMF-7 and it does help tighten up the sound.

 

Of course I'm completely serious. Here are the thoughts from George Merrill, one of the first turntable designers to design around center and peripheral clamps 30 years ago: http://www.hifigem.com/record-weights-and-clamps.html

The LP record ranges in weight from approximately 80 grams (Dynaflex 1969) to 200 grams. Most pressings weigh from 100 to 130 grams. One reason the heavier and thicker records sound better is the vinyl will not vibrate to the degree as the light weight records. The 180 and 200 gram records are the choice for less vibration, and can render better sound. The rule is simple, the more damping applied to the LP the better it sounds. This result can be obtained from its own vinyl mass or external. To achieve the best external damping, the record vinyl needs to come in total contact with a vibration damping material (mat). In the past a few record mats have used small rings or points to support the record in a few places. This flies in the face of common logic.

Holding the record to a damping material is the job of weights and clamps. An LP record’s label is thicker than the vinyl playing surface. The label varies from approximately 20 to 60 thousands of an inch thicker than the vinyl. A record mat will have a depression in the center to allow the record vinyl to lay flat, otherwise the label would be the only contact point. If a center weight is used that is very heavy, let’s say 2 lb. the lighter records will lift from the mat. This happens because the mat depression edge will act as fulcrum. This information tells us we should use a center weight tuned for the record thickness and weight. However this is impractical. Here is the solution: Use a center weight that weighs 8-12 oz . This weight will work with all but the lighter records. The alternative to a weight is the screw down clamp. These clamps have pluses and minuses. The plus is down force on the record can be controlled. The minus is if not designed properly (unfortunately most are not) spindle energy is coupled into the record. It takes very little intrusion of external energy to cloud the mechanical output of the stylus. (I wrote a paper on proper screw down clamp design about 25 years ago.)

The best answer is the periphery clamping weight along with a center weight. The weight balance between these two should be calculated for even and optimal down force on the entire vinyl area.

As the stylus traces the groove, energy is radiated in all directions, as it reaches the periphery of the record it then reflected back into the groove area. The periphery clamp will help damp this edge energy before it is reflected into the groove area. The center weight also acts as a damper. The first production periphery clamp was used on the Merrill Heirloom Turntable 1980. Kenwood also introduce theirs about the same time. Other manufacturers are now discovering the benefits of this type of clamp system.
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The typical idea behind clamping is to terminate vinyl resonances and couple the LP to the platter/mat material which would be of a sort designed not to reflect energy back into the record, not to decouple the record from the platter. Of course if you're clamping with something that's coupled to the spindle its a good idea to have some way of keeping any motor energy coming through the spindle from traveling through the clamp to the record, but with clamping or something like the Sota vacuum hold down system, the idea is for tight coupling between the record and some kind of damping platter.

And even Michell's own description of its clamping system is: "The supplied black felt washer is placed on the spindle. Then place the record on the platter. When a record is placed over the washer, the record label area will remain raised slightly. Now place the clamp on the record, press and turn the knurled knob clockwise to lock the unit. The record clamp's peripheral edge will force down the outside of the record label area thereby causing the record to completely contact the platter surface."

The goal off the washer is to deal with the record label depth and the platter/mat indent area such that the record other than the label area is in as tight contact with the platter/mat as possible.

 

It seems quite sound. Keep the record in good contact with a mat that damps vibrations. A normal weight and clamp don´t do this though, they are actually lifting the record instead, in many cases, which is not good. VPI have a good solution, some others also. Personally I believe the weight of the record is enough.

 

If I worked for Michell I would suggest to that rep that she find another line of work because she clearly has no idea what she's talking about (or, you misinterpreted what she said). The platter doesn't generate rumble, the bearing does. This is transmitted up through the spindle. In some ways a clamp can have a downside as noted above, as you are firmly coupling and transmitting any bearing rumble to the LP. You want this energy to be dissipated somewhere other than through the LP to your cartridge, so that is why the LP should also firmly contact the platter. What you have may sound good to you, but you're still using the clamp in a manner in which it was not intended.

John K.

 

Remember "The Pig" that was supplied with Revolver turntabes of yore? I still have 2 of them!

 

project debut carbon...

 

I use a clamp (it's a weight really) every time...always.

 

I made a hockey puck clamp to experiment with and see if it made a difference with my Technics 1200 and after some careful listening I found that it did, the bass was tighter and everything sounded a little more together, I don't know how else to describe it. Not a night day difference, but it was there. I didn't like the look of a hockey puck though, and it was only 6oz. I ended up buying the Sleeve City record weight. It's 16oz, looks good and costs under $50. I don't know how people get away with charging what they do for some of the weights I've seen.

 

Does anybody have any experience using Audio Technica's very affordable and apparently highly rated record weight? It isn't as pretty as a metal weight, but it weighs 600 grams/1.3 lbs.

http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=0N06RV58NB6TY53CPRRZ

 

I also use the J. Michell clamp. Best turntable gift I ever received. Holds nearly any type of warp aside from edge warps snug to the platter.

 

I've owned that weight since 1981. I guess it was my first audiophile add-on. And it does a good job at taking small warps out of some records. Pretty heavy for the price right now. Lot of bang for the puck...I mean buck.

I currently use an inner and outer (periphery clamp) weight from VPI with my Scoutmaster. I've gotten good removing the weights and flipping the record. My secret? When I remove the periphery clamp I hold it between my knees.

It's some extra work but my ears tell me it's worth it.

 

Just curious, but what do cork platter mats have to do with clamps? I am looking at the cork mats and everywhere I see them there is someone mentioning they "go with record clamps". I have no desire to have a clamp but I am wondering why I see a thread about cork mats clamps are also mentioned. Does it matter? Do cork mats have issues I am unaware of? I just want to replace my felt mat with something a little better without spending too much money.

 

I use a Groovetracer weight with the matching delrin platter....

 

cork mats do not require the use of a clamp but they can work well together. (if that is what you are asking)

 

Thanks, yes that clears it up. I have been looking at cork mats and trying what kind to get. There are hundreds to choose from and many of the reviews mention clamps. Don't want a clamp (at least for now) but just the cork mat.

 

not to go too far off the topic of clamps but....

cork mats are great for eliminating static, absorbing some vibrations and preventing movement of the LP on the platter. If you are not replacing an exiting mat and simply putting it on top of your existing platter, it will raise the height of your record in relation to the tone arm and cartridge. This will change the vertical tracking angle. If you do not have that adjustment on your arm, the benefit of the cork mat may not be a net gain to your sound quality.

 

Yes, actually Dennis I have that adjustment on my tone arm and have questions about it... I have an AT-LP120 so it came with the cheap felt mat. Would a cork mat simply replace the felt mat or would I need to raise it up? Are some cork mats better than others? I prefer a flat one, not the ones with the raised "bumps" on them. Just something like this (which is 9 bucks at Amazon). The one below looks like what I would need but is there a difference? This one is the cheapest and they go up to 50 bucks. The one from Turntable Lab is 20 and it looks like it might be a bit more sturdy than this one. This one looks like someone used a cookie cutter on a cork board. But if there isn't too much of a difference maybe I should go cheap? I am only looking to replace the felt mat. I believe the ones below are cut 1/8 thickness.

 

I would go with just replacing the cheap felt mat and not worry about it. I wouldn't go with the extra thick mat, if you play many 180 gram records a thick mat and a tick record could be enough to make an audible difference.

 

Back in the day, I remember the professional radio station turntables using cork mats. They were great for slip-starts. By the 70's, most had felt.

 

Thanks, I believe I will go with the cheap 9 dollar one pictured above on Amazon then. I haven't really had any issues with the felt mat, but it feels cheap and thin.

 

The purpose of a clamp is, as Chervokas explained, is to more tightly couple the record to the platter or mat to damp vibration in the record (caused by the needle tracking the record). Even those with a washer around the spindle are intended to increase coupling not decrease coupling. The small washer around the spindle raises the center of the record, the clamp which presses down on the record beyond the diameter of the washer acts to bend the record downward causing the outer portion of the record to press more tightly against the platter or mat. This deliberate "bending" of the record is why these are called "reflex" clamps.

Whether tight coupling and increased damping is, to some extent, a matter of taste and system synergy. I personally like the tighter, cleaner sound from improved damping, but, other might find that sound a bit "dark" or "dead." You really do have to experiment. I also like the decrease in the audibility of ticks and pops afforded by good damping of the record. The energy imparted into the vinyl by the needle tracking a big object or depression in the vinyl is quite substantial; damping that energy quickly so it does not reflect back to the stylus substantially reduces how loud and long such event will be. With good damping of the record and a tonearm that does a good job of also dissipating such energy, ticks and pops become substantially less obtrusive.