How important is the tonearm?

01-27-11: Dan_ed
The job of the tonearm is to hold the cartridge in the groove with the grip and determination of The Incredible Hulk while maintaining the finesse of Tinkerbell.

could you explain what characteristic would allow one tonearm to inherently "hold the cartridge" better than another tonearm? i would prefer an answer with specificity over a generalized "it is widely known" type of response. i ask this because as long as the tonearm is rigid (and all tonearms of which i am aware has this characteristic) then i am having difficulty understanding what the difference really is.

what does seem to me to be of importance is the effective mass of the tonearm, but the signiificance of this must be evaluated based on the compliance of the cartridge that is to be mounted on the tonearm. here, i can see a consideration that has importance. but this is a matter of effective mass and not of the specific brand of tonearm. the reason why you care about the effective mass is because the compliance of the cartridge is a measure of the spring properties of the cartridge. when the effective mass of the tonearm is not properly matched with the compliance of the cartridge you can get resonances at low frequencies that can make the cartridge become unstable in the groove. but this analysis would suggest that what you really care about in a "good arm" is one whose effective mass is appropriate for the compliance of the cartridge. so the real question that i am referring to in my earlier comments is, what other characteristics about the tonearm have concrete significance? it is hard for me to grasp assertions that a $10,000 tonearm is better than a $100 tonearm simply because the former costs 100 times more than the latter.

paperw8, heres what I've seen with a Linn Sondek going from least to best tonearm available in the shop.

#1, quality of arm doesn't affect groove tracking, thats really a matter of good bearings and good match between arm mass and cartridge so that irregular record surfaces don't excite a wow/flutter effect. You can get excellent groove tracking in any properly made cartridge above $100

2# quality of arm does affect the ability to trace microtransients and not distort peak transients. A mediocre arm reduces that sense of "air" in a recording and direct to discs will make you want to shoot the arm and put it out of its misery. The arm basically rings like a bell at unpredictable frequencies and amplitudes in sympathy to the stylus vibration.

Better arms have fairly sophisticated schemes of minimizing resonances. Beware of any tonearm with dangling parts, thats a resonance PITA. An excellent tonearm should have a machined approach like jewel movement swiss watches.

01-30-11: Davide256
2# quality of arm does affect the ability to trace microtransients and not distort peak transients. A mediocre arm reduces that sense of "air" in a recording and direct to discs will make you want to shoot the arm and put it out of its misery. The arm basically rings like a bell at unpredictable frequencies and amplitudes in sympathy to the stylus vibration.

Better arms have fairly sophisticated schemes of minimizing resonances. Beware of any tonearm with dangling parts, thats a resonance PITA. An excellent tonearm should have a machined approach like jewel movement swiss watches.

i see. this sounds like a pretty reasonable explanation. i have a triplanar tonearm and one thing that i have noticed is that the tonearm seems very dead in the sense that if you tap the tonearm the material from which the tonearm is made deadens vibrations. an impulse tap contains a fairly wide range of frequncies so that test would suggest to me that the triplanar tonearm is not particularly prone to coupling longitudinal resonances along the wand.

Oh dear oh dear.
The old 'tap' test again..........

What's wrong with taps for a dead arm? Sorry, the devil made me do it.