Hi Wid,
Well, I've never heard that but then it would depend on which Grado you tried to put into a more massive tonearm. Grado makes some very expensive Signature cartridges that have very delicate stylus assemblies. To perform best, these really require a custom separate tonearm.
But the lower-priced Grados ($100 or less) should be fine, unless there is some shielding issue. The Grado I used to use was a Signature 8, and it worked fine in custom SME tonearm on a Scottish turntable (Ariston) that was a clone of the Linn.
Generally speaking, the more massive the tonearm, the greater the tracking force you have to use. Most Japanese direct-drive turntables should be run at about two grams tracking force.
Alan
