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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
dwette OP
77 posts
 
@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.

lewm
6,770 posts
 
 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.
terry9
931 posts
 
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.
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