It's not hard to identify the material of nut and bolt. Identifying the exact alloy is very hard, but perhaps not essential. Best to assume industry standard alloys and published tables, and then take care not to exceed.
Also (at the risk of ribald levity), if the mating surfaces are very lightly lubed the required torques are lower and more easily adjusted. I always start low and increase until the sound begins to deteriorate, then back off to the previous setting.
Most of the improvement seems to come from equalizing torque, but there is still more to be had by optimizing.
IMO. YMMV. |
I believe that the screws currently recommended for the Palladian cartridge are made of titanium. Moreover in a separate communication, the inventor associated with acoustic sounds was very positive about the need for titanium screws for best sound. However I don’t recall that he said anything about torque. The maximum permissible torque for a given screw of a given material would not necessarily apply To a determination of the optimum torque for screws that hold a cartridge in place, with the object of best sound quality in mind. So since best sound quality is an elusive and subjective quantity in the first place, I don’t know how anyone would know the best torque for screws used to mount a cartridge. “Don’t overtighten” is good enough. Or experiment with torque to suit yourself.
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@spatialking That torque chart is qualified with the following statement, and therein lies the rub, as far as I’m concerned. Keep in mind that this is only an estimated value. It may provide satisfactory performance. Every application needs to be evaluated on its own to determine the optimum torque for each application
I don’t think I want to trust a torque value for a specific bolt unless it comes from the cartridge manufacturer. I for one don’t want to destroy my $3K cartridge and rather err on the side of the bolts being maybe a bit too lose and/or slightly inconsistent between the two. I tighten mine very gingerly, just enough for the cartridge to stay put. |
You can find a torque table here for various types of metal for small machine screws: http://www.federalscrewproducts.com/torque-chart.htm I don't believe nylon has a torque value as it certainly strips easily. The torque numbers come from the manufacturers of screws and bolts, as they have ASTM standards for alloys and the materials that make up the screws. Note that if one were to apply torque to a screw with a nut on the other end, then the torque applied to the nut also comes into play. That is, one has to sum the torque applied to the nut and the torque applied to the screw to get the correct total torque. If the nut doesn't rotate, the cartridge along with the headshell doesn't rotate, then the torque reading on the wrench (or torque screwdriver in this case) would be correct. I must have a hundred+ small screws left over from cartridges. Some that came with the cartridge but never fit and I had to use screws from other brands. Some were too long, some too short, gosh I think I have every material of which small screws were ever made. In general, I prefer either aluminum, brass, or stainless screws. I have used nylon but only as a last choice. The screw material the cartridge comes with is my first clue on what to use. I never torque cartridges, partly because I never owned a small & spiffy torque screw driver and partly because I am happy to just get the dang cartridge aligned without ruining it! I am sure I would destroy a cartridge sooner or later if I tried to torque them! |
I for one do not remember ever seeing an actual torque spec for any cartridge I have ever purchased or investigated the specs of online.
Not saying nobody provides them but not seen it yet.
Now I am not claiming my fingers are an accurate torque wrench at all but every cart I have ever mounted has been by feel and definitely NEVER overtight.
However if you are a bit of a klutz this method may not work very well for you! |
While I don’t have the spec for my cartridge’s (Audio-Technica VM540ML) mounting screw torque, I’ve requested that of the manufacturer just recently. If I get an answer back, I’ll share it here.
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At 11:54, "Torque values have nothing to do with sound."
At 3:23, "Of course these things matter. Of course they affect the sound."
Yeah, sure, whatever, Mr. Miller. Goodbye. |
The correct way to tighten something is according to the manufacturer’s specifications. They know more about their products than anyone else does.
These are the manufacturer specs for fixing the bolts on my Clearaudio Concerto V2, given in the installation manual... "Please take care to not overtight them by force" How many cartridge/tonearm manufacturers provide this spec? |
The correct way to tighten something is according to the manufacturer’s specifications. They know more about their products than anyone else does. |
I sometimes wonder, do people bother reading any more? Or is it why bother, when reading in (ie, just making stuff up) is so much more fun?
Oh well, the words are still there, for anyone who cares to bother to try and understand their literal meaning.
As for the rest, while nothing like what I said, nevertheless is worth discussing. Of course these things matter. Of course they affect the sound. I say that not because I've done the comparisons in this particular instance, but because I have done the comparisons in enough other instances to know there is ALWAYS a difference.
Unfortunately, this blows out of the water the whole idea of following torque setting guidelines! Because, if torque makes a difference to sound then obviously the correct way to tighten is by ear.
Think it through.
Yes he is full of it. QED. |
Sleepwalker, thanks for the correction. I'm a little anal-retentive about tools since I saw a VP vaporize a prototype because of faulty instrumentation. |
Fremer trusted it enough to use it, whatever his initial impression.
Do you really think that the force holding two mating surfaces together has no impact on their dynamic behaviour? Really? Do you not think that variables such as material (plastic or wood or metal), mating surface, lubrication, and human habits of tool use, might make a difference? And that posted values are for guidance, but that ultimately experimentation is definitive?
As I said, the torque values suggested came from a post by a Linn engineer who had studied the matter in some detail. You declare that he is "full of it". What is your evidence, please?
You also seem to be saying that all tools are equally reliable, accurate, and repeatable. But remember Fremer. |
Accuracy of torque wrenches is relatively unimportant compared to getting consistency of torque when it comes to tightening lug nuts (or wheel bolts if we’re talking German cars). There, a Harbor Freight torque wrench will suffice. On the other hand, if you are assembling an engine, you need a much more accurate torque wrench for nuts on bearing caps on connecting rods, bolts on main bearing caps and head bolts.
Jumping back to thr topic, yes, a high precision torque screwdriver is required to properly tighten the mounting screws of a cartridge to headshell, especially when we’re talking about a $500+ cartridge. |
I used a Sears Craftsman Torque wrench (maybe $100?) on my M3 at the track. Never had an issue with it. |
Fremer with a cheap torque wrench? As if. No, it was as high-end spendy as everything else in his lair. And read what I wrote again. He didn't trust it. He was TOLD to trust it. And so, dutifully following instructions, he destroyed a very valuable cartridge.
The Linn engineer is talking his own book. That's being polite. Torque values do not come from cartridge makers. Torque values come from engineers. Torque values have nothing to do with sound. Torque settings are derived entirely to be tight enough to not come loose while also not breaking or overly stretching the bolt. At no point does how it sounds enter the picture. There are torque tables for every gauge and diameter and quality of metal. There are no torque tables for cartridge model. The Linnie is full of it.
btw I have the Porsche, and the spendy torque wrench, and being a PCA Instructor have seen plenty of cheap torque wrenches being waved around at the track. They all work just fine. |
How does one determine the correct torque for headshell bolts? If I get one it would be the analogmagik mentioned above. |
As for Fremer’s trust for the wrench - internet "bargain"? I’ll bet it wasn’t a high end industrial version, like Stahlwille. I mean, what kind of sucker would pay all that money for a tool he could trust?
I remember, at a track day, one of the Porsche drivers waving around a box store torque wrench. A $50 wrench for a $150,000 car. Riiiiight. Had a nice looking case for it, though.
Look up the Linn engineer who discusses cartridge torques and the level of precision required for an optimal setup. Maybe some hands can reliably sense a 5% difference, but for the rest of us, a quality torque screwdriver is an important setup tool. |
I ended up not liking the vinyl screws. I think they softened the high end and dynamics a bit. At the moment I am using stainless bolts, but 5mm instead of the 8mm I had before. That brings the stainless 49gr counterweight about as close to the arm's fulcrum as possible. It sounds great and when I run the test record the resonant frequency is at or near 10 Hz, as far as I can tell. The whole system tracks beautifully and sounds great, with very well focused bass (I use Confidence C2 Platinum with a pair of REL R-328 subs).
When I changed the cartridge bolts I realized a torque wrench is probably not necessary. With my Concerto V2 and the Universal headshell it's very easy to tell when the bolts are snug enough without over tightening. It's a very solid fit when somewhat thumbtight using the long oreientation of the small hex |
Listen to Michael Fremers story about destroying a many thousand dollar cartridge with a torque wrench. He has never overtightened and only did so because he was told to trust the wrench. My hands and his are far more reliable. YTMV.
I've swapped parts out like this before. Stainless usually sounds the best. |
I always joke with my prosthodontist when I see her regarding the use of her "torque wrench".
Newton meters....?
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Second the torque screwdriver for cartridge bolts and nuts. I use a premium Stahlwille tool (as in Mercedes shops), and it made a significant difference. Not only was the torque made to be consistent, it could be optimized as a set-up parameter. Easily the difference between two high end MC - for $500!!! And the Stahlville will never need a retip!
YMMV |
@vasaudio Thanks but not this time. I don't know how I would even audition such a change, but I also want to leave the warranty intact. I will probably upgrade my cartridge this year. |
If you are interesting in another upgrade, I can upgrade the tonearm wire for a smoother, warm sound. Great for vocals. |
Thanks for the tips about over-tightening. I don't think that's ever been a problem for me in the 4+ decades I've been playing records. However, that analogmagik torque-wrench is intriguing. Given that my TT/arm/cartridge are close to $15k it may be a small price to pay for getting things as dialed in as possible. There's always Valentine's Day coming up. :)
FWIW: I use the Clearaudio protractor (essentially Löfgren A and B). I have used B in the past but am using A now, mostly because I play a lot of classical music. I would love to have a table with two arms: for jazz and classical. |
I don't know if it's still in production (it's not on their website), but Rega was at one time making a cartridge bolt torque wrench. |
And, as @folkfreak points out, never over-tighten!
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Aural memory is like gustatory memory: capricious, inconsistent, and unreliable. Much like my college dating history. If you don't notice a sonic difference, then don't worry about it. Listen to the music, not the system. Anyhow, my cartridge mounting stuff is a - Dr. Feikert's protractor
- Analogue Productions Test LP
- Shure VTF scale
- homemade oscilloscope for azimuth
- needlenose pliers
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My experience is that in my setup choice and use of bolts is a fairly important factor. Acoustical Systems who make my cart (Palladian) recently switched from stainless steel to Timet 1100 screws and the audible effect of this change was not subtle - see the discussion here (btw the screws are now standard and mine were free, but they are costly if you want to try them on another cartridge) https://forum.audiogon.com/discussions/the-palladian-a-step-beyond/post?postid=1377437Another thing to bear in mind is the torque you use. Over tightening is the real issue and a tool such as this helps if you are anal (I purchased it just so as I could be sure but frankly can’t say I felt the difference was that large however I was very close to the recommended torque anyway) https://www.analogmagik.com/product-page/analogmagik-torque-driver-package |
