Record clamps: Ok, consider me converted.

[Arkay]

A couple of thoughts:

1. It's easy to understand Linn not recommending a weight, if it causes more bearing stress than the bearing was designed to accommodate, But a clamp? The clamp serves to force the record against the platter, by leveraging it off the spindle; the actual clamping force adds no additional stess to the bearing at all. What does matter, though, is the weight of the clamp. If the clamp weighs as much as a weight, then it will cause as much additional bearing stress. However, if the clamp is lightweight (say, made of a lightweight plastic and only a few ounces) then it should be safe for the bearing.

2. The idea that the weight or clamp stresses the vinyl record is true; however, the effects of that stress need to be weighed against the effects of the record warp itself. A stylus riding up and down over warps will have audible distortions that almost certainly would be MUCH greater than any internal stresses inside the vinyl itself, which may or may not be audible. They might be, especially if they affect the groove shape and/or the manner in which the stylus moves against the groove walls, but I'd like to see some real evidence, before I'd believe that these possible effects could outweigh the effects of a warp. I'm extremely skeptical that this this claim of Linn's holds any validity.

3. The important aspects of a weight or clamp are (1) reduction in record warp; and (2) better contact between the record and the mat. Lesser effects include (3) greater inertial mass of the whole platter assembly (which adds rotational stability), plus (4) dissipation of vibration from the top surface of the record, into/through the weight/clamp (and possibly into the spindle. Obviously, if the platter is of the suspended type, the extra weight of the device will also alter the tuning of the suspension.

4. Whether and how much a clamp or weight affects the sound, will depend on all of the above interactions, and will vary from TT to TT.

5. For a suspended TT, a lightweight clamp is preferable, because of the effect of the additional weight on the suspension. For an idler or DD TT, a weight may be preferable, or at least as good as a clamp. For example, the bearing on my GT-2000 was designed to accommodate an optional gun-metal platter that is significantly heavier than the stock platter. It can handle several pounds of extra weight without difficulty. The same is true of the motor. You can burn off your fingerprints with friction,if you try to stop the platter from rotating. The rotational stability is ridiculously high with this motor, and a few pounds of weight will not materially affect it. So a weight is fine for this TT, and may work as well or better than a clamp (depending on various characteristics of the particular weights and clamps).

NOTE: If you have a suspended TT and wish to use a weight with it, there is no reason you cannot tune the suspension to accommodate the added weight. However, since most suspended TTs are also belt drives, you have to consider the effects of the added mass on the belt mechanism (which may or may not be significant).



Which is better - a weight or a clamp? There really is no simple answer to that question, without considering the specific TT the device is being used with.

 

[marc mc]

Ok, Back on track!

The OP is using a clamp (weight) on a turntable that the manufacture has stated cannot improve the sound "if he really listens". And will ruin the main bearing if he continues!

How's that for a fast track?

Marc mc

 

[jgordon]

Lots of varied responses to the original post, many interesting.

For the love of god, please leave off with the linn vs. all else debate. It really doesn't matter what we think of the companies at this point.

As for Linn (or any other company) recommending a certain path and none other, many companies do this. My other passion is old cars, specifically porsches (no, I only have one). In my porsche forum, just like in this one, there are those who say "don't change a thing - porsche must have known better than we possibly could" and there are those who say that we, and others, sometimes come up with ways to improve on the original design. The fortunate thing is that we can each purchase a table, and tweak it or keep it original as we see fit.

As for the weight vs. clamp debate, I think there's some merit to it. I understand that Linn designed their bearing with a certain weight in mind. I'm no physicist, but I have trouble believing that a 5 oz weight (0.34 lbs) will significantly deteriorate the performance of a hardened steel bearing, which is supporting a 9.3 lb platter. That said, the Michell clamp is 2.4 oz, so half the weight.

Again, I bought 3 pucks for $5.99, so the options are varied and cheap. I'm going to ask the woodworking shop to put one on the lathe, and bore out a centered hole at 19/64's, which is what I have now. Although mine is probably a millimeter off-center. I'll have them do another at 5/16, which I think will effectively eliminate the spindle-grabbing sticktion, and simply function as a weight. On the 19/64, I'll ask them to bore a few lightening holes in it as well, to make it more purely a clamp.

I think the toughest part of this on the table is putting it on. I use a light twisting motion to drive it down the spindle until it engages the record and twists it a little bit. This is probably the harshest treatment for the bearing, and I can see the benefit of ceasing that. So after a bit of messing around, in all likelihood I'll pull the trigger on the Michell.

But if $5.99 can inspire 5 pages of discussion and debate on audiokarma, and inspire a few people to try new approaches to sound reproduction, it will be well worth it. And I'm having fun while I do it. Much more than $5.99 typically buys. And for me, half the fun of vinyl is the tweaking, the experimenting, and the debate and idea sharing with you guys.

 

[marc mc]

As for clamps and weights I have or have used everything. I use an aluminum billet one I had made on my Lenco GL 75. I used a Mitchell on the Heybrook. The VPI acrylic on my MKiV, steel on my platterless table, none on my PF 800 or my TD125mkii.

Marc mc

 

[bluesky]

I wouldn't use a record clamp/weight on my 1980 Sansui SR-838, I like the TT too much. I'd personally just be really scared to do damage to the motor and bearing(s). Anyway, it sounds just fine as is.

If you think that you have sound problems...just get a better, higher quality, mat for the platter. One that 'grips' the record really well.

The SR-838 has a fabulous mat...so I'm happy as is. No problem here.

But record weights/clamps sure do look cool, but add 'weight and drag'. Was your TT designed for that???

As they say, and is very true: "For every action there is a reaction". I don't need any 'reaction' with my TT. :>) Seriously. I love it 'as is'. I just leave it alone and it works just fine. Leave well enough alone.


My professional opinon would be:
If the manufacture 'supplied' a record weight/clamp with the TT, use the exact model they supplied. If there was no mention of a record weight/clamp to be used with your 'vintage' TT...Don't use one. That's just my logical thinking. Better to be safe than sorry, expecially if you really love your TT.

 

[ehoove]

I am really attached to all my Thorens tables, and use weights on all of them. I do have polished SS thrustplates on them that can be replaced if need be which I doubt.
Regards,
Jim

 

[Divotdog]

I also use weights on all of my Thorens tables, as do I use the same thrust plates that Jim uses, so far all of my tables have not had any problems, if it does wear out a bearing I will be the first to report it, then I will replace the bearing and reinstall the weight.

 

[jgordon]

Marc,

What I'm hearing is that you use some sort of clamp or weight on all of your tables. Which would support the thesis that they help.

As for the argument of whether the designers of the table intended their use, let me ask you something. The average record is between 100 and 140 grams. Audiophile LPs are 180-200 grams. So the extra weight of an audiophile LP is equivalent to 1.4 - 3.5 ounces. Would you say the designers of the table never intended for its use with a 180 gram LP? And therefore never play one?

I'm comfortable that the Michell, at 2.4 ounces, or the hockey puck, at 5.5 ounces (less if lightened) do not pose a threat to the design parameters of the table. If these are really that highly stressed, and at the outer edge of their tolerances, then these guys weren't as bright as I'd like to believe.

A better platter mat with more ability to both hold the record in place and absorb vibration is an interesting middle ground. I think the herbie's mats are said to do this. They start at $60, making it an interesting alternative. If I had more cash, I might get both and do a comparison. As is, While I see the merits of the argument, I'll probably mess around with hockey pucks for a while.

 

[jgordon]

Located a woodturner with a lathe and a good sense of humor. He'll put a hole in two pucks for me, one at 19/64 and one at 5/16.

If his patience proves out, I'll ask him to mill some material off of the pucks as well, shaping them somewhat conically (my mental image is of the Michell clamp.

Who knows - maybe I'll go into business selling milled and shaped hockey pucks with this guy if it works out.

 

[iLUVanalog]

"Let's please not get into that tired debate "

the only tired thing is the head in the sand about adding unnecessary weight. if added weight were to be a benefit, it would be at the periphery, a great place to press downward, like a clamp, improving record contact to the surface of the platter.

It's really insulting for you to assume that anyone who favors a weight somehow has their head in the sand. I can assure you my head is NOT in the sand, and there is no need to resort to that sort of thing. You think clamps are superior to weights....great....got it. But don't state that as an absolute (which is what you did).

As I said, there are pros and cons to BOTH types.

This whole "clamps versus weights" thing has really been done to death.

 

[iLUVanalog]

.....

 

[iLUVanalog]

A couple of thoughts:

3. The important aspects of a weight or clamp are (1) reduction in record warp; and (2) better contact between the record and the mat. Lesser effects include (3) greater inertial mass of the whole platter assembly (which adds rotational stability), plus (4) dissipation of vibration from the top surface of the record, into/through the weight/clamp (and possibly into the spindle. Obviously, if the platter is of the suspended type, the extra weight of the device will also alter the tuning of the suspension.


+1000 on this. THIS is the whole raison d'etre for using a "clamping device" of some sort.

 

[ARJohn]

I bought the Mitchell clamp to use on my diy RCM set up , yeah $60 was a bit pricey but I can use in on 2 of tables , both sprung . I find it does improve the sound , not night and day mind you , but stuff seems to sound better . Also for some Lp's that have a hump in the label area , it does flatten them out and puts the Lp surface in contact with the mat , so can't be bad thing .

 

[Pio1980]

The addition of rotational inertial mass of a weight is close to nil due to it's small relative radius, a peripheral clamping ring OTOH would add a substantial amount.

 

[UncleAng]

I always used a clamp on my previous tables because I believed it improved the sound regardless of matt composition. Have not used one on my Heybrook as I'm afraid of wearing out the springs and replacement parts are hard to come by.

There appears to be regional preferences on the use of clamps/weights with many German and the US manufacturers endorsing them vs. few British.

 

[melofelo]

here's the pickering red button clamp on my 3 point suspended for those interested trying one. They do look good when spinning !

 

[hifitommy]

now THAT'S the way to go. almost no mass. a friend of mine used one of those quite successfully.

 

[jgordon]

The things I do for you guys...

OK, so here goes.

Tried to find a lathe in manhattan. Which proved, as you might imagine, to be a completely fruitless search. Fortunately, there's a guy in East New York (fairly rough section of brooklyn) that does woodworking, and he allowed me to mess around on his lathe for a while.

First we rigged up a chuck that could actually hold the puck. Then we had to get a bit into the other chuck, which was set up for milling laterally, and therefore was only to hold a piece of wood, rather than drill or bore. Finally got everything set. Got the holes done. Figured as long as I was there, I'd make a few adjustments and decrease the weight a bit, in deference to the concerns voiced here (and my own).

I did two pucks. Ended up doing one heavier than the other, which has not appeared to make much of a difference. This supports the theory that it is the presence of the puch, acting as a weight and a vibration dampener that is responsible for most of the improvement, rather than the weight itself.

Also ended up drilling the holes at 5/16, which is a little too large. I read a spec on the linn spindle as 19/64, but when I did 19/64, it came out tight. The 5/16 is just about right. But my hunch is that the lower rpm of the home drill allowed material to flex out of the way, rather than be augured out by the bit. So I'll likely head back and do a few more at 19/64. Maybe even one at 9/32.

Now for the conclusions. There is an improvement over no puck, but it's not as drastic as with the original, overly tight one that I had to screw down onto the spindle. So that suggests to me that either a clamp, with some force exerted on the spindle, or a heavier weight, will be needed to approach the improvement I was seeing originally. And to be honest, I was getting a little uncomfortable exerting that much weight on the spindle and bearing.

I'm happy to post more after I do the next round at 19/64 and 9/32.

Any suggestions or thoughts?

 

[hifitommy]

BEAUTYful!

 

[gunpoet]

Very nice! Can't wait to see more!