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Krystal torque
2017-09-18, 08:00 (This post was last modified: 2017-09-18 08:23 by smokestack.)
Post: #11
RE: Krystal torque
(2017-09-17 12:52)Peer Gynt Wrote:  In the case of the cartridge LP12 torques, sample to sample variations make such high precision in torque measurement hard to justify.

I won't argue that you can't torque tune a deck by ear. But the idea that you can write down torque specs for general use to a hundredth of a Newton meter is hard to defend with credibility.

I tend to agree.

Especially when talking about relatively low torque settings, friction variables in the fasteners etc will tend to muddy the issue a little.
That said, settings do help to stop folks breaking things.Wink
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2017-09-18, 08:04 (This post was last modified: 2017-09-18 08:18 by Glyn Ruck.)
Post: #12
RE: Krystal torque
Thread pitch, material, lubricated or not etc. will all vary values. Austenitic stainless steel fasteners frequently used to mount cartridges can gall & seize also affecting values.
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2017-09-19, 15:47
Post: #13
RE: Krystal torque
(2017-09-18 08:00)smokestack Wrote:  
(2017-09-17 12:52)Peer Gynt Wrote:  In the case of the cartridge LP12 torques, sample to sample variations make such high precision in torque measurement hard to justify.

I won't argue that you can't torque tune a deck by ear. But the idea that you can write down torque specs for general use to a hundredth of a Newton meter is hard to defend with credibility.

I tend to agree.

Especially when talking about relatively low torque settings, friction variables in the fasteners etc will tend to muddy the issue a little.
That said, settings do help to stop folks breaking things.Wink

Indeed it does stop folks breaking things, and here unless I'm mistaken, we are only talking about cartridge bolt torque here. Now if try applying the above to other fixings....... Like for example the 1/2 inch Super Pan self tapper screws used to secure various items such as top-plate, cross-member and hinge brackets to the plinth. Of course all four finishes of plinth (as Rosenut and Walnut are the same - Just a red stain) and let's just keep it to Linn plinths for now, without introducing some of the exotics we could......They have quite different density and structure. Indeed, individual plinths may vary in their density within millimeters. This is before I could get started on the various different 1/2 inch screws that have been used by HQ across the years. These screws vary in thread width(size), pitch and consequently feel (you may call it resistance, torque or whatever) as it's being tightened up......... Ditto for the 3/4 inch screws of course, only the usable thread length and hence contact area is greater and so whilst I totally agree that tightness is critical to set-up and hence performance, personally I have been a long term and quiet advocate for the feel method based on experience which personally I consider better. I believe results and independent recommendations here and elsewhere would bear this out.

Now then, when tightening down a cylinder head or maybe a con-rod bolt for example, I absolutely would use a calibrated torque wrench and tighten to the published manufacturers specification for that individual bolt. I would also tighten in the precise order specified too. Thread size, length, thread type/pitch the materials involved and the job it was doing within the engine (system) all being considered, but for a self tapping wood screw of varying length, type and being fastened in to a plinth which we also know varies due to species and on the microscopic level, I will continue to trust my wrist until RSI gets the better of me Smile


KR

Peter

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2017-09-20, 01:57 (This post was last modified: 2017-09-20 01:58 by Peer Gynt.)
Post: #14
RE: Krystal torque
50 years ago, a legendary Norton mechanic, when asked about head bolt torque for the Manx answered

"Just torque 'em down until they stretch and then back off a bit."

In typical high quality assemblies nowadays, calibrated wrenches are used (I have four in different ranges myself). But typically to a tolerance of 10 to 20 percent.

In critical assemblies, the angle of rotation method is nearly always used. There are gauges for this purpose.

The fixings in an LP12 are all pretty much statically loaded but subject to vibration.

The method espoused by that old Norton mechanic would fall into the "feel" category, and would work well for a seasoned LP12 builder.

My guess, and I emphasize the word guess, is that when someone suggests that 7 Nm should be 7.05 Nm, then what they're probably really reflecting is the idea that a hair over is better than a hair under.

I can respect that. And I certainly respect the idea that a seasoned LP12 set up artist might torque tune a deck to some effect.

Just listen .... or not
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2017-09-27, 19:19
Post: #15
RE: Krystal torque
Since the simple request that started this thread and the relatively simple answer to it have caused much speculation, and some incorrect conjecture, I thought I should try to clarify the idea of using precision torques once again. Especially since I am the one who discovered the technique and have taught it to many dealers and LP12 owners around the world over the last dozen years.

First off it has been clearly stated several times that the precision torque technique relies completely on listening to the small or large changes in torque and determining the optimum setting using the tune method. In doing this it has been found, by myself and many others, that changes in torque of one or two hundredths of a Newton meter (about as small an adjustment as the torque drivers can make) are indeed audible and have an important musical effect. It has also been found that the effect is repeatable and consistent for a given fastener and interface. Whether this is understandable based on a mechanical engineer's understanding of how torques work is no more important to the people who use this system than the electrical engineer's inability to understand why a different Ethernet cable sounds different. They do sound different (both the Ethernet cables and the torques) and that is what important. Furthermore, I can easily demonstrate the musical effect of different small adjustments of torque to anyone interested and have done so many times. This technique is applicable to most, but not all, fasteners on a turntable and also on speaker drivers and crossovers and electronics. All Lejonklou products, except phono stages where the circuit boards are not bolted to the case, have labels on the inside specifying the torques for all fasteners on the product both internal and external.

Now, like any other LP12 technician who has worked on a number of LP12s for a few decades (I am a few months short of 40 years) I learned a long time ago to adjust tightness of fasteners by the feel of the tightness that gave a good sound, as Peter has talked about. I think all of us learned that when we graduated from the "Linn tight" school of putting a steel pipe on a hex key to see how tight we could get the arm height bolt (yes, people actually did this). Back then the goal was to get things as tight as possible without breaking them. Eventually saner minds prevailed and it was noted that tightening any specific fastener beyond a certain point stressed the materials and made for a less secure fitting. So we all graduated to being a little less gorilla like in our setups and over time found that how much we tightened things made a sonic difference. Linn, having realized the downside of "Linn tight" in terms of broken items eventually did publish a few torques specs, mostly in service manuals, so that people wouldn't break things. Two easily discovered ones are the Kandid torque of between .8Nm and .9Nm (also applicable to Arkivs and Akivas) and the top plate bolt in the motor corner of between .4Nm and .6Nm. I expect publishing these in the manual or on a sticker on the cross brace helps reduce the number of broken units.

What I did approximately 12 years ago was to take the torque screwdriver I bought so that I could meet Linn specs and combine it with the known fact that you could hear differences from the tightness of most fasteners to see if I could quantify the torque setting where it was most tuneful and whether it was consistent. I don't think anybody was more surprised than I was that there was a significant difference in musicality with differences of a few hundredths of a Nm of torque and I tried it out on coworkers to make sure I wasn't hearing things. But everybody heard the same improvement two notches on the driver made (and later one notch, somewhere between .01 and .02Nm). Once I found this worked on some LP12 fasteners (the first ones I experimented with were the two main bolts that hold the top plate to the plinth) I tried it on other fasteners and found that it worked on most, but not all, of them. This was shared with others, most notably Fredrik Lejonklou in Sweden and Paolo Nobile in Italy, and we found a high level of consistency in the torques that were most musical and that they were indeed repeatable. Some of these were even on items we didn't think it would work on. The main thing is that all of us found that you could hear smaller changes in torque than what you could feel so it allowed us to achieve a higher level of musicality than we were able to do by feel alone. I have yet to find anybody that can actually feel the difference of .01 or .02Nm of torque.

So some clarifications. As mentioned this relies totally on the tune method so I understand why Peter prefers not to use it. He has stated elsewhere that he "tunes" things for a front of the concert hall perspective which is not part of what the tune method is about. He likes doing things this way and his customers obviously like it and that is fine. (Though I believe he could be more consistent in that goal through the use of precision torques.) Equally obviously my customers are very happy with the way I tune LP12s.

As to the question of different woods in the plinths that is actually pretty much a moot point. I (and others) have found that there are a few fasteners on the LP12 where torque makes no musical difference. The first ones I noticed that on are the screws that hold the Trampolin or Urika to the plinth (although the torques WITHIN the Urika are indeed audible). These could be taken anywhere from just snug up to where they would almost strip without audible difference. I'm not sure why, it's just the way it is. Similarly the locating screws on the top plate and the ones that hold on the wiring strap don't have an audible torque - get them good and snug and you are fine. I suspect this is because it is the torque of the bolts that clamp the top plate and wiring brace to the plinth and blocks are the important ones here and they are quite audible. Indeed, the only screws I have found that go into actual wood that have an audible torque are the ones that hold on the hinge plates. I didn't initially think that these should make a difference but, just as the plinth sounds worse without the plates it sounds better with the right torques. Interestingly even these seem to be consistent. I have to suppose that what is actually creating the torque is the pressure of the head on the plastic fitting more than the threads pulling against the wood.

On the comment: "But the idea that you can write down torque specs for general use to a hundredth of a Newton meter is hard to defend with credibility." this is also a misreading or a misunderstanding of the torque method. You will note that I did not give a specific torque in my answer but rather a narrow range. I was trying to keep the answer short so I didn't give my usual disclaimer. But to clarify things I will give it here. I have received quite a number of requests for info and torques and I am happy to help (there obviously isn't enough of me to go around and setup all the LP12s out there and I feel everybody deserves the best sounding LP12 they can have). So I created a boilerplate explanation which I am copying here:

"I can give you some help with the torque values I have found but you will have to fine tune them by ear as the torque screwdrivers can easily vary by plus or minus 6% which is larger than the differences I find musically important. I use a Sturtevant Richmont CAL 36/4 for setting torque. This is also used by Fredrik Lejonklou and Paolo Nobile. This driver is calibrated in both in/lbs and in Nm, which is the scale I use, and covers the range from .2 to 4.0Nm. This is a near perfect range for adjusting turntables as the lowest torque setting I have found so far is .2Nm minus 9 notches for the motor wires to the Radikal sensor board whereas the highest is 3.8Nm plus 1 notch for the bearing housing to the Keel. As to the notches there is a small flip-out handle on the bottom you use to adjust torque, which has a tab and a series of 9 notches that it can fit in to hold it in place. I label my settings by going to the nearest mark (.2Nm increments) and then how many notches above or below that mark is the correct setting. Fredrik, Paolo and I have found that 1 notch (less than .04Nm) is audible on most settings with 2 notches making a clear difference. We have even had a few cases where we use a half-notch setting. Best bet to find a driver is either to google Sturtevant Richmont CAL 36/4 or check eBay for a used one -which is how I bought mine. New they sell for anywhere from about $140 to well over $200. On eBay they show up all the time and rarely go for over $50.

On the SR torque driver there is a clear plastic indicator that is convex to magnify the numbers on the scale a bit. There should be a black line in the middle of the bulge and that is the reference to use for the settings. I recommend adjusting it so the black line on the plastic is centered on the reference for the Nm setting nearest the one you want to try. As an example, if you were going to start at .8Nm you would center the black line on that and then flip the handle down such that it falls in one of the notches on the bottom. Since it can flip both ways one way should put it pretty much in the notch and the other way it would be on a land. Once you have located the proper notch you count the number of notches above or below (clockwise or counter-clockwise) to get to the place you want to be. So .8Nm-7 notches would have you finding the .8Nm mark and going 7 notches counter-clockwise."

As you can see, each person using the system has to tune by ear using any torques I supply as guidelines since the torque drivers aren't consistent to that degree from one to the next. The drivers themselves are very consistent over time and very precise, allowing the small increments we have discussed, but they vary a little bit one to the next. I have calibrated a few drivers for Fredrik against my main driver (we both own several) and Fredrik calibrated one for Paolo so we are able to relate our measurements fairly closely although there is still sometimes one notch difference.

So I think that better explains what the precision torque method of LP12 setup (and indeed setup of virtually any piece of Hi-Fi gear) is all about. As always, I am glad to answer any questions people have.

LP12SE Movingui • KRadikal • Kandid • Urika • Kremlin • LS-NAS • KRDS • Lejonklou Sagatun Monos & Tundra Mono 2As • JBL 3677s & 4645C Sub • NOKTable • Harmoni Mimer/Tor Racks
AV: Pioneer BDP51 BluRay • Akurate Kontrol • 2 LK280 SPARK • 4 Isobarik DMS • 2 DQ1W

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2017-09-27, 19:36
Post: #16
RE: Krystal torque
Thomas ~ no dig here, but the art of effective communication is brevity.
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2017-09-27, 19:46
Post: #17
RE: Krystal torque
(2017-09-27 19:36)Glyn Ruck Wrote:  Thomas ~ no dig here, but the art of effective communication is brevity.

If you had been on here a number of years you would know that brevity is not one of my typical characteristics. Some like it, some don't.

LP12SE Movingui • KRadikal • Kandid • Urika • Kremlin • LS-NAS • KRDS • Lejonklou Sagatun Monos & Tundra Mono 2As • JBL 3677s & 4645C Sub • NOKTable • Harmoni Mimer/Tor Racks
AV: Pioneer BDP51 BluRay • Akurate Kontrol • 2 LK280 SPARK • 4 Isobarik DMS • 2 DQ1W

www.nokturneaudio.com

Fine-tuning LP12s since 1978!
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2017-09-27, 19:50 (This post was last modified: 2017-09-27 19:51 by Glyn Ruck.)
Post: #18
RE: Krystal torque
(2017-09-27 19:46)ThomasOK Wrote:  
(2017-09-27 19:36)Glyn Ruck Wrote:  Thomas ~ no dig here, but the art of effective communication is brevity.

If you had been on here a number of years you would know that brevity is not one of my typical characteristics. Some like it, some don't.

Having read this forum extensively before & after joining I'm well aware of that.
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2017-09-27, 20:50
Post: #19
RE: Krystal torque
I don't think sane minds will be swayed.

Listen with your own ears. If it sounds better, it is better.

Just listen .... or not
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2017-09-27, 22:57
Post: #20
RE: Krystal torque
I am curious to know what wrench Thomas is using and who does the calibration.

My smallest, most precise, has first scale in inch pounds and second scale in Nm.

The Nm scale is given to two decimal places, but this is an artifact of the conversion from the primary scale. The increment on the Nm scale is .11 Nm. This is an expensive, calibrated micrometer type torque wrench. The range is from about 6 Nm to about 29. It is possible to buy one to cover the 1 to 5 range. It has an increment of adjustment of about .05 Nm.

But even after calibration, the accuracy is recognized to be no better than 10%. Precision is a measure of the increment of adjustment. Accuracy is a measure of how close the measurement is to the true value.

I understand that this torque tuning ritual is believed by some to produce hearable, repeatable, worthwhile results.

I don't want to steal the intellectual property, but I would like to know the brand and model of the wrench.

Just listen .... or not
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