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Cartridge Mounting Hardware

I recently upgraded my tonearm to the Clearaudio Universal. This is a great arm and worth tweaking and experimenting a bit to get the best out of it. My cartridge – Concerto V2 (7 gr.) – came with several sets of cartridge mounting bolts: 5 mm nylon and aluminum flathead screws, and 8 mm stainless hex bolts. No nuts since my cartridge is tapped for the bolt threads. For years I've been using stainless bolts. With those I use a 49 gr. stainless counterweight and it sits nearly as close as it can go to the fulcrum when VTA is dialed in. When I play the Hi Fi News test record the resonant frequency of the arm is more or less at ~10 Hz as far as I can tell.

Conventional wisdom – AFAIK – says that's all good. 

I recently saw a Clearaudio photo of my arm with another one of their cartridges in the line (also 7 gr.) and it's mounted with the nylon screws. That got me to thinking about trying it, and maybe trying the aluminum ones too. With the nylon screws I can no longer use the 49 gr. stainless counterweight, and have to change to the aluminum 31.5 gr. counterweight, but that sits farther out away from the tonearm fulcrum (although it looks cooler, IMO). I'm trying that now. With the test record the tonearm resonant frequency is still right around 10 Hz. I'm playing music now and don't notice a difference, but my aural memory for such things sucks, so I have to live with it for a bit, and then revert to see how I feel. This weekend I'll play some records I use to test out setup changes and see if I hear anything for better or worse.

So that makes me wonder what others know and experience about cartridge mounting hardware (and techniques). What's your wisdom on the matter?
dwette
millercarbon's avatar
millercarbon
12,531 posts
 
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.
dwette OP
166 posts
 
I used a Sears Craftsman Torque wrench (maybe $100?) on my M3 at the track. Never had an issue with it.
sleepwalker65's avatar
sleepwalker65
832 posts
 
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. 
terry9
2,333 posts
 
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.
terry9
2,333 posts
 
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.
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