tonearm questions

Raul is correct about the internal wire being better on the new SME V. HOWEVER, if you buy an older one, and send it back to the factory for service (which you should do anyway) SME can install an even BETTER van den Hul wire than what they put in their current production arms.

That's what I did with my 16 y.o. arm.

I don't like suspended tables, mostly because I think they're a pain in the ass to use, but a unipivot on a suspended table -- I don't think so ;--)
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Rolloff, the internal wiring of the SME IV is a metallized ribbon, not wire. Supposedly, this presents less resistance to the bearings, and is also supposedly more compatible with MC cartridges -- for which this arm was specifically designed. So you wouldn't want to change it IMO.

The arm itself is not that old , maybe 5-8 years? You can find out but it is much newer than an SME V, and unless "you don't know where it's been" it shouldn't need routine service.

As for the damping tray, I can't tell you if you really need it or not because I can't find any info on the compliance of the Shelter 90X. (You probably don't.) Most MC cartridges have low(ish) compliance and are appropriately used in med to high mass arms (like the SME IV.) So the arm doesn't need to be damped as far as resonances are concerned, though it can help to keep the arm from overshooting the lead-out spiral, but that shouldn't happen if the table is level and the arm limit properly set.

Now if you were to use a high compliance cartridge (like a van den Hul, or many of the MM or MI cartridges) in a med/high mass arm, you might find the damping helps.

Here is a quick overview of the issue:

http://www.gcaudio.com/resources/howtos/tonearmcartridge.html
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ALWAYS drop the stylus into the first groove and not into the lead-in spiral -- for all the reasons Doug says. Yes it requires eyesight (glasses?) and a little practice -- but any decent engineer has cut a few seconds of silence into the first track, so you won't miss anything once you get the hang of it.

Rolloff, maybe I misunderstood. Did you add the curved horizontal damping trough? -- the one that comes standard on the SME V, or are you talking about something else? (I don't understand how it helps with VTA for instance.)

Also the SME IV comes with a damped cueing lever, so why would you need the Thorens Q up -- or is it an automatic device for convenience?

Dave, excuuuuse me! I completely forgot about the height adjustment screw that's incorporated into the damping trough piece (more likely I "repressed" rather than "forgot" it because it's such a pain in the ass to use!)

If you haven't read the long thread I started on determining proper stylus rake angle (SRA, a term more descriptive of reality IMO than VTA) go here:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1140840022&openmine&Nsgarch&4&5&st0

As for your question about antiskating forces, it is somewhat counterintuitive isn't it!? The INWARD directed force is the result of the tonearm being either "S" shaped, or having the headshell cocked at an angle -- both designs are ways of keeping the the tonearm physically short (9 inches) while minimizing the tangential error of the cartridge alignment to the grooves. (Early tonearms were 12", 16", or even 18" long, straight, with no headshell offset.)

However this "offset" design creates a virtual "lever arm" which when pulled on by the friction of the stylus in the groove, tends to twist the arm inward.

The easiest way to visualize it is to imagine tying a string to the front of the cartridge and pulling on it. The motion of the tonearm will be in toward the center of the record.

If the tonearm post, the armwand, and the headshell were all lined up straight and you pulled on the string, nothing would happen. But with modern tonearms, if you draw an imaginary centerline thru the cartridge front to back extending it backwards, you'll see that the line misses the tonearm post by a couple of inches (to the right). The friction in the record grove multiplied by that two inch virtual lever arm creates an inward twisting force (torque,) which must be counteracted by an equivalent outward twisting force (antiskating force) in the opposite direction. Now, isn't that just as clear as mud !? ;--)
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