Hi Harvey, the solution is inelegant but effective: increase the effective mass of your tonearm. The easiest way is with Blu-tak and quarters on the headshell, then move the counterweight back to compensate to achieve the correct tracking force. If this works, then the Twl tweak is the way to go, with weights attached to the sides of the main bearing to increase mass, more elegant too once the experiment is confirmed. There are weights out there which are meant to increase trhe mas of the cartridge, which increases the tonearm's effective mass. Elegant-looking solution too.
Hi Mario: I did in fact try my RS-A1 very briefly, and with the tapped headshell I simply didn't have an untapped cartridge in my arsenal to compare with the Concerto or the Benz LP, all simply outclassed. So it was down to the SME IV/Concerto (in my system superior) or JMW/Concerto (in Rick's system superior). I will be reaming out the threads, finally. I do LOVE the combo of RS-A1/Denon DL-103"E", which is not only neutral tonally and extremely detailed, but ROCKS like all get-out with incredible PRaT!!! Of course, the Grado's richness and midrange magic will always be the Grado's signature: the MAS/Grado Woody combo will be reserved for my Electro-Voice system.
Have fun all!!