Removable headshells 101

Timeltel has raised the subject of the rubber 'O' rings normally supplied between the headshell and the locking-collar of the tonearm.
Fidelity Research abhors them and Yamamoto headshells also are supplied without.
I have largely eschewed them with all my removable headshells but would be interested in the benefits that those who use them, claim to hear?

I was around in the old days and always took the washers out. There is nothing wrong with detachable arms except lack of rigidity, which is arguably less important for MMs, which are inevitably themselves less rigid due to their replaceable stylus. I recently bought a Jelco 750 to use on my back up table, I hadn't had a detachable arm since the early 80s. When looking at older headshells look at ones made from cast magnesium [ like the Lustre] or similar rigid material rather than flimsy designs full of holes that were designed for minimum mass rather than rigidity. The ADC cast aluminum ones were quite good. I got sticker shock when I looked at some of the new ones and I have enough old ones to use anyway.

Like Stanwal I was also around in the (good) old days and
also took the washers out. But to be honest I forget the reason why... I also agree with my old mate reg. Jelco 750
wich has different names as well different price in different countrys (Sumiko in the UK and ? in Germany).
To my knowledge the best headshell for the price. If the money is not an issue you may look for those Orsonic or
(Clearaudio) Stability headshells.

Regards,

My knowledge is limited when it comes to discussions regarding headshells and I'm interested in learning as much as possible. Please feel free to pass on any websites etc.

I've just arrived here with a SAEC WE-308SX plus the 18gr ULS-3X headshell. I'm very excited but full of questions about almost everything. So, please if you don't mind to share your knowledge :
* Do you know any confirmed successful general rule for choosing the right HEADSHELL ?
* What matters the most for a successful CART/shell pairing
* How to choose the right combination of cart/shell/ARM ?
* What is the importance of the BUILD MATERIAL (between 2 headshells of equal weight) on sound reproduction ?
* Is it good to combine DIFFERENT materials for cart body/shell/armtube in order to break the resonances ?
* Is there any SEQUENCE of prefered materials following the transmition of the resonances ?
* Is there an UPPER LIMIT of the headshell's weight concerning the arm mass ? (if the counterweight can support it of course).
* How to recognize the good LIGHT WEIGHT headshell for your high compliance cartridge ?
* Any known excellent partners that is worth to mention ?