Removable headshells 101

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 ?

Dear nandric: IMHO the best headshell is the one that makes your/the cartridge really " sing ".

I have no preferences for headshell because some ones works great with some cartridges and " bad " with other cartridges even with the same cartridge but different tonearm a good one in one tonearm could be a bad one in other tonearm.

Resonances/distortions everywhere the tonearm/cartidge/headshell/TT/platform/etc makes almost imposible to predict the result between headshells and cartridges combinations. IMHO we have to try and decide through several tests.

So and in this subject said/say that this or that headshell is the best has IMHO no real foundation.

Remember that when an " important " persons/reviewers/guru in audio stated that this/that audio item is the way to go then we think is the best and when we have it almost always will sounds good for us even if not: we are prepared for that audio item sounds good way before we hear it.

Only our skill/experience/know-how level in audio could tell us what's " real " and what's only " illusion ".

Regards and enjoy the music,
Raul.

If the headshell is light in weight and it sounds dead (doesn't ring) when you tap on it, it is a good headshell.

I'm surprised at Raul's response.
Whilst I can appreciate that what he has experienced may indeed be true.......to then throw up his arms and state that he has no understanding of the reasons for the performance changes of various headshells is contradictory to what he is always stating about the need for us to 'understand' the reasons behind good tonearms and poor tonearms, good turntables and poor turntables?
Raul carefully lists all the factors that play a part in tonearm design and turntable design yet here, with the (relatively) simple parameters of the 'headshell'.......it's all too difficult?
Try it and see?.....maybe it's 'magic'?

Well I don't believe it's 'magic'.
I think there are certain basic physical and structural principles that govern a removable headshell design and the 'magic' may be related to cartridge/tonearm synergy?
That 'magic' is complex enough......let's not create myths and illusions at every twist and turn of the analogue chain.
To the uninitiated, it would appear that analogue is just too complex to bother with?......and that is just not the case.

Firstly I'd like to destroy the myth that removable headshells are in some ways inferior to 'fixed' headshells?
In 'theory', this must be correct as any possible movement or weakness in the rigidity chain between cartridge and arm-board is potential for information loss.
But we all know that in audio, the chasm between 'theory' and 'practice' can sometimes be vast?
The best sounds I have ever heard reproduced in my system have been with tonearms which have removable DIN phono connections and removable headshells.
I have 3 other arms with fixed headshells (or in the case of the Copperhead....no headshell at all) and unbroken phono cables form cartridge clips to phono input.
So how is this possible?

I'm not sure that the weight of the headshell is, of itself, a consideration apart from its affect on the effective mass of the tonearm, but all the theory again about high-compliance cartridges in low-mass tonearms and low-compliance cartridges in high-mass tonearms I have found in my experience to be unreliable?
Why don't we comment about the mass and construction of the fixed headshells in tonearms?

For me, a removable headshell must have a structural logic and connection to its aluminium or magnesium socket tube.
If the connection to this tube is weak, it will allow torsion or twisting to occur and if there is an off-set between the headshell proper and this socket tube, then a bending moment is created which may allow movement.
The best removable headshells generally are those that are integral with the cartridge.
The Technics EPC100Mk3 and the Fidelity Research FR-7 group of headshell/cartridges are prime examples of these and it's easy to see that the axis of connection to the socket-tube is directly in line with the axis of the headshell.
This structural logic is utilised by Micro Seiki in their H-303X headshell for the MA-505 tonearm HEADSHELLS
Of course there are other points to consider and hopefully this thread will illuminate those?
But I refuse to concede that headshell design is a 'black' art :-)