This one:

The Maplenoll and the Sota rule the waves.

Best wishes!

Buddha-

I'm not a turntable expert but is it advisable to use a record clamp with a direct drive turntable? I would think that the last thing one would want to do would be to more strongly "couple" the record to the spindle/platter which is of course DIRECTLY attached to the motor (the MAJOR source of vibration.) I'd think that "decoupling" with a upgraded record mat would more be in order. Plus may be some spikes to help drain vibrations out of the 'table.

Thoughts?

If I remember correctly, the DP47 is a direct drive table and I would also discourage coupling the main spindle to the LP to the stylus.

What is the op trying to achieve that a record clamp would solve? If it's "better sound", then the Denon leaves few options.

clamping the record will drop the overall noise floor. Long story. Whether it is DD or belt.

It will drop it in two ways, transfer and micro jitter in speed, caused by backward motion of the record on lateral shift of the stylus. This leads to better delineation in the dynamic envelope, besides the effect of correct and large peak transients. The two work together.

This is the one of the main reason that Art loves his massive rim drive Thorens 124: Massive instantaneous torque. Which is CRITICAL. rubbery mats damage that effect, to some degree, and felt decouples but kills dynamic expression via micro-cogging on the stylus lateral shifts.

Which is why many folks like the ringmat. It grabs just a bit better.

Clamps work quite well, viewed through the correct eyes. But I can't put one on my LP12, the suspension won't handle it. Not designed for it. Pity.

I understand the function of a record clamp. That's why I asked what the op's intent would be. If the clamp is intended to flatten warped discs, then that is one thing. If the op expects certain sonic improvements to be gained by the addition of a clamp to this turntable, then that is quite another issue.

I would still contend a record clamp on a direct drive table of modest book cost is not going to accomplish the desired results. Why? First, if you are going to make the case for better clamping to the platter, then you must consider the platter in this case to be the extension of the low cost motor in this DD table. As such, it has inherent flaws in noise and micro-speed control that canot be overcome by the addition of a record clamp. Indeed, the case is being argued the clamp will only make matters worse. If you are more completely coupling the disc/styus to a motor that has these noise and speed deviation issues, then the benefits of a more complete coupling are irrelevant if not totally counterproductive.

Noise floor is not likely to drop when you tightly couple the disc to the motor, that is the raison d'etre for belt drive tables. If it wasn't beneficial to decouple the motor from the disc, Vilchur would have closed up shop in 1959 and Ivor would still be working at a used tire shop still thinking and still hoping for his big break.

Let's say none of the speed or motor issues do exist and consider the other results of more closely coupling the disc to the platter (mat) of this table. The DP47 was a basic Japanese DD table, as such it had a typical Japanese DD table's hard rubber, ribbed platter mat. Experimentation is always the key to improvements but I wouldn't be betting that particular platter mat is what you want to clamp a disc to. The hard rubber doesn't hold the disc securely so micro-speed resolution is doubtful and it has pockets between the ribs where trapped air will create resonances the clamping action will only exacerbate rather than remove. The platter itself is prone to ringing when excited - excited, say, by a cogging motor. A more complete coupling to a ringing platter and a resonant disc surface that allows micro-deviations in speed will provide what benefits? Are these not isues the Ringmat was designed to eliminate?

I'm not sure what the Thorens reference means in this context. Yes, high torque on demand and the heavy flywheel effect of the massive Thorens platter would be benefits of the Thorens design but neither advantage is to be found in the Denon, quite the opposite in fact is present in this table.

Quote:
Clamps work quite well, viewed through the correct eyes.

Once again agreed, but you must view the Denon as a table that embodies many of the low end, mass market features the high end turntable market has stepped away from. As a product, the DP47, with its automatic functions tied to the tonearm, could be the poster child for all that was wrong with most mass market turntables in the waning years of Japanese table design.

Before the op searches out a record clamp, I would agree the Ringmat or suggest even a cork platter mat would be more beneficial. Without a clamp, even a felt mat would be superior to the O.E.M. issue. However, on the whole the DP47 still leaves little room for improvement and remains what it is, a low to mid-priced, two decade old, mass market Japanese direct drive table with a boxy frame and a not very good "S" tonearm with a detachable and highly resonant headshell.

Not to insult the op but tweaks to this deck are somewhat like hotrodding a 1984 Chevy Nova. The platform just isn't worth the effort compared to starting with a superior product and working from there. If this is where you are beginning with analog, then use the table until you can afford better. But save your money and don't get serious about changing the overall sound quality of this turntable. Investing more than a few dollars in a better isolation system is probably not money wisely spent.

(A DIY platter mat can be constructed from a stiff sheet of artist's watercolor paper and a dozen or so cork dots from the hardware store. Buy cork in a thickness that will not radically alter the vertical tracking angle of your cartridge/stylus, the end product should be approximately the same thickness as the Denon O.E.M. mat. Cut the paper to size and punch out the spindle hole. Arrange the cork dots in an undulating pattern across the paper, leaving a slight bit of free space at the inner and outer edges to accommodate the record label and outer lip. Using this in place of the O.E.M. mat will very likely result in a more "organized" and lively sound that the original mat provides.)

Quote:
Buddha-

I'm not a turntable expert but is it advisable to use a record clamp with a direct drive turntable? I would think that the last thing one would want to do would be to more strongly "couple" the record to the spindle/platter which is of course DIRECTLY attached to the motor (the MAJOR source of vibration.) I'd think that "decoupling" with a upgraded record mat would more be in order. Plus may be some spikes to help drain vibrations out of the 'table.

Thoughts?

I'd call it a trade off between the benefits of the clamp vs, the detriments of more close association with motor issues.

For the direct drive tables I've played with, I prefer to change the stock mat and use a clamp. (Almost like creating a constrained layer beneath the stylus.)

I even thought the old grey felt mat made by I-forget-who with a clamp made for a pretty noticeable improvement.

We could ask the same clamp questions for other turntables, as we are putting weight on the spindle and increasing noise and friction that way, too.

Quote:
We could ask the same clamp questions for other turntables, as we are putting weight on the spindle and increasing noise and friction that way, too.

Only in a few designs might this be the case. Most manufacturer's clamps are a screw type or an actual clamping type that would add little if any downward pressure or weight on the spindle bearing. A record weight would be a different issue. Anyone know of any company recommending record weights nowdays? I don't unless you count the VPI peripheral clamp.

I seriously doubt you'll be able to find a drop on weight that has sufficient mass to actually flatten a warped disc. If you do, it will very likely be so massive it will cause motor/bearing problems. Check with a retailer such as MusicDirect asking for a reflex clamp of some sort.

http://www.musicdirect.com/product/74432

Jan, the guy obviously likes his table. You didn't have to be an ass. You ass

Jan, the guy obviously likes his table. You didn't have to be an ass. You ass

Jan the guy obviously likes his table you didn't have to be an ass. you ass.

I constructed for my Pro-Ject 1.2 what I call "The 78 Cent Clamp". Using a circle cutter in my drill press at low speed, I cut three similar sized circles out of 3/4" Medium Density Fiberboard (MDF) from scraps left over from other projects. Through the three circles I drilled and fine tuned a center hole to fit a turntable spindle. On one of the circles I laid out radial lines 60 degrees apart for six equal segments of the total circle. Using a 3/4" Forstner drill bit I drilled a 3/4" hole completely through the piece at each 60 degree interval. Then I glued the second circle piece to the bottom of the first that now has the 6 holes evenly spaced around the radius point. Once the bottom is glued on, I placed 13 pennies in each hole. The penny will fit snuggly within the 3/4" hole and not shake back and forth if moved in a sideways motion. The 3/4 " MDF thickness allows for the 13 penny stack with just a little room left over but not enough for a 14th penny. The six holes times the 13 cents in each holes equals "The 78 Cent Clamp". The third piece is then glued to the top. Since I wanted the clamp to fit under the Pro-Ject dustcover, on a table saw I trimmed about a quarter inch off the top and the bottom. The edges were then sanded smooth and flush. I was going to apply a coat of Polyurethane, but sanded MDF sort of looks and feels like suede, so I left it in the raw state.

The clamp is heavy enough to provide a modest degree of record flattening if the warp is near the center. Does it improve the sound? Hard to say for sure. Sometimes I think it does but then sometimes I forget to put it on when playing a record and don't realize it until I take it off. It does add an upscale look to an otherwise budget table. Now that I have the pure white Corian platter, I might have to paint the clamp to match. The feet of the 1.2 have been replaced by "Painting Pyramids", available for a few bucks at Home Depot. They are little plastic pyramids about an inch and a half high. Their purpose is to hold a workpiece to be stained or painted up off the work surface so the ends and sides can be reached. But they also make a fine set of turntable feet. Maybe not nearly as effective as say some carbon fiber cones at 50 or 60 bucks for a set of three, but I can seriously stomp around or give the shelf a good thump, and nothing comes through the stylus. I have since painted the Pyramids reddish-orange to match my Bellari VP-129. I use two pyramids on the left side, as close as possible to the original foot position. The third I put on the right side directly at the center of an imaginary line between the two original right side foot locations.