To some extent, there is bound to be a trade off in using a record weight and ring. While you will flatten records and get better coupling between record and platter, you may increase bearing noise through the added weight of those two pieces. That added noise combined with better coupling of the platter to the record, may significantly increase the noise heard through the stylus. It may also render some bearings inadequate or non functional, such as an air bearing or magnetic bearing. On my Transrotor Fat Bob, which has a magnetic bearing, I havent heard a problem using both, but it already has a massive platter and magnetic bearing. On a Rega, you might have a different result. |
Manitunc,
I agree, magnetic bearing's like yours and on Clearaudio's bigger CMB tables are unaffected by the additional weight. |
Raul:
I'm not sure that I completely understand you, but my observations suggest that peripheral, vacuum and center clamps can all be positive, as long as the clamping force that they impart can be adjusted to the needs of the individual situation. And in general my experience has been that too little is preferable to too much.
I will add that center clamps help to terminate the noise and vibration caused by the spindle bearing - these devices address more than just the LP.
Also, the material and construction of the clamp are definitely audible.
BTW, was this question a prelude to some Raul-designed clamps which will again show how the AHEE has led audiophiles astray? (^0^)
cheers, jonathan |
Rockitman,
I dont know if I agree with your statement that the additional weight will not affect a magnetic bearing. Depending on the strength of the magnet, it may not be able to maintain the separation between the bearing surfaces. And with some magnetic bearings which only lessen the load on the bearing surface, not eliminate it, the extra weight could have a negative effect. |
Dear Jcarr: Yes that was the meaning. Thank you. No, nothing to design , only learning about.
Regrads and enjoy the music,
Raul. |
Dover:
My TT-1000 by itself has a little less mass in the platter system than stock (I needed to shave down the top of the platter to get a flat surface for the graphite mat to bond onto). Add the center clamp, and the net weight ends up pretty close to stock - not enough to warrant readjusting the servo gain.
Still, your point is valid - the servo control of a DD is typically set up with a certain load range in mind, and if the user alters the load significantly from what the manufacturer originally intended, it is a very good idea to reassess the servo gain.
I will add that many DD turntables were designed with a specific lubricant in mind. Some turntables were even designed so that the spindle functions like a self-pressurizing, self-centering Archimedes pump (similar to many PC cooling fans today), and if you change the lube, you may adversely affect the self-centering action of the pump/spindle.
I know that various DD models by JVC, Yamaha and Kenwood fall into this category. I recommend reading http://37282.diarynote.jp/200708102338400000/ and http://37282.diarynote.jp/200708111505150000/ These pages are in Japanese, so you may need to send them through a translator.
The A.R.T. graphite mat that I have bonded to the TT-1000 (using a permanently non-hardening adhesive, causing it to function like constrained-layer damping) has a recess for the LP label, and yes, I have done much experimentation with washers under the LP. Here again, I suggest using these in moderation - only as much as needed to bring the edges of a dished-up LP back in contact with the mat (or platter surface). My testing has suggested that imposing physical stress on an LP while playing it (which is what too-enthusiastic use of washers is wont to do) will adversely affect the sound.
Dover, you have a Final Audio? So do I (grin). My unit predates the Takai-era Parthenon, but is new enough to have the SPZ plinth rather than the original granite. It also has the bi-phase motor controller. FWIW, Kitamura's preferred material for mat and clamp was chrome copper rather than gun-metal. I haven't done A/B tests on chrome-copper vs. gunmetal, but based on A/B tests that I have done on gunmetal vs. other metals, my conclusion is that gunmetal isn't a material that I would care to use for sonic applications. I prefer the results with phosphor-bronze or beryllium-copper, and I imagine that chrome-copper would also work well.
cheers, jonathan carr |
05-18-11: Manitunc
Rockitman,
I dont know if I agree with your statement that the additional weight will not affect a magnetic bearing. Depending on the strength of the magnet, it may not be able to maintain the separation between the bearing surfaces. That's a given Manitunc. I can easily see the clearance between the magnetic bearing and platter on my table...I agree, too much weight so that the platter makes contact with the bearing would be bad. |
Manitunc, Rockitman, magnetic bearings are another thing that I've done experimentation on. In my experience, using the magnets to unload most of the platter weight from the bearing, but leaving some mechanical contact intact sounded the best (a kilo or less, probably even a half-kilo would suffice).
IME, the sonic benefits of keeping a mechanical path to drain away vibrations trump the lower noise levels of a floating bearing. OTOH, if the finish and lubrication of the bearing points is such that significant noise and vibration are generated as a result of the mechanical contact, you may arrive at different conclusions.
Some of the La Platine Verdier turntables allowed the user to adjust the amount of magnetic levitation, and use the configuration that sounded best to him.
cheers, jonathan |
"IME, the sonic benefits of keeping a mechanical path to drain away vibrations trump the lower noise levels of a floating bearing. OTOH, if the finish and lubrication of the bearing points is such that significant noise and vibration are generated as a result of the mechanical contact, you may arrive at different conclusions."
That is an interesting explanation. May be that is why I tend to prefer mechanical bearing vs Magnetic bearing in my Clearaudio Master Ref analog set up. The Magnetic bearing may not have efficient vib drain path (just a spindle of some ceramic material) to the Everest Stand my CMR rests on |
"IME, the sonic benefits of keeping a mechanical path to drain away vibrations trump the lower noise levels of a floating bearing."
Would not the sleeve/platter interface provide a pathway to drain vibrations, or does the lubricant interface effectively prevent vibration tranfer? |
I believe the magnetic bearing in the Project RM10 only unloads the platter from the bearing and doesnt isolate it completely under the same theory that a drain path is desirable. So essentially you have a regular bearing with minimal load and therefore minimal friction and noise with the advantage of a heavy platter for rotational momentum |
J Carr
Hi Jonathan, interested in your feedback on centre clamps. My main concern on the gunmetal Final Audio clamp is that the spindle hole has no sleeve so it has metal to metal contact and it is not snug. I have often thought it would be an advantage to mill out the centre and put a teflon or other polymer sleeve in, but this is a one way trip. Do you have any recommendations on heavy clamps.
The other query is that on the Final the record edge is ever so slightly proud of the platter/mat, therefore I assume peripheral clamps may not be ideal on this turntable - thoughts ?
Might as well ask a third - graphite mats - a friend had an unfortunate experience where his cartridge ended up gummed up with grey scale off the graphite - comments ? |
Dover, how did the graphite mat get the "grey scale" onto the cartridge? I've used a Boston Audio Mat 1 (graphite) for years without problems and the only one I'd replace it with is a Mat 2. |
The mat was the Millenium, which has a smooth and rough side. I assume its off the rough side, but I dont know if the gentleman is using it correctly. Hence the question. |
My experience with clamps is that when I use my TTWeights Classic, I get noticeably better sound I think because the flatter records creates a more consistant azimuth, right? I lusted after the VPI center weight and when I got it it made my turntable sound horrible. Even my wife noticed a difference. You could play half a song with the VPI and then lift the cue and put the TTWeights on and immediately tell the difference and same if you did it in the other order. I think some bearings can handle a little extra weight but there's a limit. |
Hi Dover:
I agree that a not-so-clearly-defined contact between spindle and clamp (neither snug nor free) is not a good idea. One some turntables, you'd want physical contact between the clamp and spindle, as this is what would allow the clamp to terminate the noise and vibration of the platter bearing. Something like a collet-chuck mechanism should do the job well. However, the FAR's self-lubricating polymer thrust plate is pretty quiet as far as I recall, and shouldn't need special treatment.
A slight overbore of the clamp combined with a polymer sleeve should be good. But not with teflon. Teflon is soft and has low elasticity, and once it is deformed, it stays that way. If you apply pressure across a wide area of teflon it stands up pretty well, but concentrated pressure on a small area is another story. Delrin or some grades of modified noryl (PPO) should be better.
You may also try a tripod-contact between the bottom of the clamp and the LP surface. For whatever reason, I thought that this worked pretty well on the FAR.
Regarding your second question, with the s-l-o-w spin-up time and all, would you really want a peripheral clamp on your FAR? (grin) Sounds damn fine without one!
I haven't had a problems with graphite mats, by Audio Tekne, A.R.T. and Boston. However, I have fabricated some parts in graphite, and I know that there can be sizable differences in the materials sourced from different suppliers. Some lend themselves to machining, and others don't. Also, for best results, graphite machining should be done by a place that is familiar with the stuff, IME.
As an aside (Dover, you already know this), in Kitamura's original FAR design, the platter was aluminum, and it was topped with a mat of machined chrome-copper. Either piece would ring beautifully on its own (although you'd not see it in the measured frequency response from the cartridge), but place the mat on the platter, and pfft! No more ringing, and a quieter, more even-handed sound delivery with greater dynamic range (although you't still not see anything on the cartridge's measured frequency response). The Japanese phrase for this type of mechanism would translate to "phase-interference damping". No idea what you'd say in English.
FWIW, I'm using the same principle in some of my cartridge designs (pressure-fitting of dissimilar metals which are chosen to suppress each other's resonant tendancies).
cheers, jonathan carr
PS. On paper, at least, another approach would be to get a snug fit between the clamp and spindle, and put a stiff grease on the spindle. The grease would lock the clamp in place and quash any ringing. You'd have to remember to wipe the spindle clean each time before removing the LP, however!
Yet another approach that you can take with clamps is to use a container filled with small ball-bearings. Staggering the bearing sizes helps to expand the range of affected frequencies. |
Regarding clamps and rings, it all depends on the turntable, the type/weight of center weight and the outer ring weight. So many vaiables, no wonder YMMV...
For my table, the TT Weights Super ring and the clearaudio quadro clamp weight sounds best for my system. |
J Carr - thanks for the info - very thought provoking. The clamp discussion certainly has me thinking. The FAR clamp has a proud rim on the bottom so the force is applied to the out edge of the label. My FAR is up to speed in half a turn - so not sure on your set up - I'm using oscilator preamp with PS Audio power amp & MIT cable in the supply & Silk thread belt. I can only think maybe I'm tensioning the belt a bit more than you. I dont think mine has a polymer thrust pad. I'm using Motul V300 Power Racing oil which is a synthetic using double esters which is very slippery and has very high unctiousness- ie in a motor it will hold a film in the head even if the motor is not used for some time. My racing mate managed to boil his porsche engine, melt brazed oil lines and still the motor kept running with no damage. I love the Ikeda cartridge, though it can be difficult - be great to see this cartridge concept continued after Ikeda goes. |
Wow - this is quite the thread!!!
I have no doubt that what Halcro (a valued poster) heard was true for his system.
However, as user of both a ring and clamp, I have found differently.
Here is an anecdote. On my current table (Raven 1), which came with a Millenium clamp and mat, I found I didn't like the sound of the mat, which seems in opposition to many people with the same table.
But, I don't run my Phantom arm with damping, though most people do.
I just feel like there are no absolutes, especially with analog.
I also run a strain gauge cartridge, which is different than most.
I appreciate Halcro's findings, and since the system here is about to change radically with the addition of the TAD speakers and new TTweights Momentus Duo drive table (I'm a new dealer for both - hear them both at the Axpona NYC show) that I will have to reevaluate the use the use of the clamp and super heavy ring the table comes with.
I will also be reevaluating the use of damping fluid in the arm, as it changes to the new Phantom version with a 12" arm. Lot's of changes, lots of testing, lots of listening, but no universal truths I'm afraid.
On another note, the new table will allow for either rim or belt drive. That's another controversy I am soon hoping to hear how it plays out. |
Hi Emailists,
Thanks for the kind words.
Perhaps the differences we are hearing on both our Ravens with the peripheral clamp, are due to the fact that you don't use the Millenium mat and I do?
Interesting......I have to try it.
Cheers
Henry |
J Carr:
The A.R.T. graphite mat that I have bonded to the TT-1000... Jonathan, have you experimented with the A.R.T graphite record clamp? It has awkward dimensions making it impossible for certain cartridges to clear the final few grooves of an LP. I have a feeling though that you are not using Koetsus :-). The above problem not withstanding, the combination of the A.R.T graphite mat and clamp is very rewarding on my Clearaudio Master Reference with magnetic bearing. On a related note, can you suggest a place that I can have that A.R.T graphite clamp 'shaved' so that it is compatible with all cartridges? |
A long thread. Took me time to read it. I just want to make a note that I have a few outer rings. I have the Kenwood outer ring which weighs about 1.3 kg and a RSR outer ring which if I remember right weighs 330 gms. What I have discovered is that is that an outer ring can be and mostly is benificial sonically (mind you I barely use it due to the PITA it presents)but that is in relation to the RSR ring. The Kenwood more often than not sucks the life out of LPs. That is why I purchased the RSR. I do use the Kenwood on severely dished LPs as the RSR is too light to flatten them. For a record clamp I use the Harmonix, my mat is a Mystic Mat and the TT is a Black Night for reference. Is is suspended very effectively.
What the RSR does is give you a touch more detail and dynamic agility.
I always wanted to design my own outer ring that would have weights that can be inserted along the perimeter to establish what weight is best sonically.
As for record clamps, I find a very slight sonic difference between using the Harmonix and not. But I do use it all the time. Otherwise the LP is not as well coupled to the platter and on startup the LP will spin on the mat.
On to mats, the Mystic Mat sounds very similar to the copper platter direct. What it does do is make the sound a hair more natural. Just a hair and blind testing if you adjust VTA I doubt most would hear it. Almost identical. I tried a Boston Audio mat and found it truncated the leading edge of instruments and made them sound flat. That is in my system. For others it might be different. As a result I am not a fan of graphite mats / platters.
As such we honestly need to look at the entire system to determine what is beneficial or not. I could see a turntable being designed where an outer ring would be beneficial provided the platter can transmit the energy stored between the LP and interface away from the stylus. |
Halcro, thanks for starting this thread. Very ear-opening. It never occurred to me to try my VPI HRX without the periphery clamp as it came with the turntable. Based on one weekend of listening the table seems to sound better without it -- slightly bigger sound stage, more open and lively. This was with the Airtight PC-1 cart and 2 drops of damping fluid in the JMW 21.7 arm Tnx again!
P.S. - When comparing having the ring on or off I found it required a 0.04 Hz frequency change on the SDS to get speed to match. YMMV. |
Perhaps some of the difference we hear with rim weights is due to whether we use a mat on the platter. On my Transrotor Fat Bob, there is no mat, just a vinyl layer which mates with the record. It is hard and has no give so the rim weight just makes sure the record is perfectly flat at is in contact with the platter at all points.
If a rim weight was used with a soft mat, I can see where it might press the record into the mat, causing a different resonant experience than just laying on the mat. I havent tried a soft mat on my Transrotor, and the only one I have is the Oracle mat which is quite soft and squishy.
for the record, I like the sound with the rim weight and center clamp. |
As Manitunc and others here have suggested.........I believe that it may be the mat in combination with the rim weight which is the culprit here?
I removed the Millenium mat from my Raven AC-3 and placed the record directly on the copper top platter together with a centre weight and the rim weight.
All the life and magic, which had previously been sucked from the presentation with the mat in place, suddenly returned.
I am unable to repeat this experiment with the Victor TT-81 DD table as the aluminium platter has a raised outer rim to contain the thick rubber mat, and without it, the record's outer edge sits upon this rim and thus does not make contact with the platter itself.
Is the sound quality without the Millenium mat on the Raven but with the outer rim weight, better than a record without the rim weight but WITH the Millenium mat?
Not really.
So unless I'm playing a seriously warped record (and I only have a few which cause problems), why would I bother with the fuss and ceremony involved in the placing and removal of the outer rim? |
