Dear Halcro: I'm more sursprised by your post:
+++++ " state that he has no understanding of the reasons for the performance changes of various headshells is contradictory to.... " +++++, please let me know where I stated that sincerely I can't remember where.
No the headshell subject as any audio subject is in no way a " black art ", things are that exist almost no scientific research that can be confirmed through listening process or the other way around and due to this fact there are several " black art " audio subjects, that's all.
Now, if you re-read the MM thread ( first page. ) I stated there that I had " bad time " with the AT 20SS till I mounted in the SAEC UL3X headshell, I tested that cartridge in those " old " times with several other headshells and in different tonearmsand till today I don't have a precise explanation about. This seems like " black magic " but certainly it's not.
A few weeks ago I posted that I had some " problems " trying to made that the ADC 25 performs at its best, well I tryed in at least five different headshells ( where my guide was my experiences about. ) with no success til with out real foundation I mounted in an aluminum AT headshell that is full of holes/perforated and is not only ugly headshell but when you see it and when you have in your hand you can't trust in it! and you know what this AT headshell was the only one that made the ADC 25 really sings.
Black magic?, certainly not but even that I would like I don't have the time to design a scientific model to find out why that happened.
In the last four years I tested around 80 different cartridges with different tonearms and different headshells and even this kind of whole experiences I can't be aware today why the ADC 25 performs so well with that AT headshell maybe you have a precise explanation and I would like to hear it and learn about.
+++++ " The best removable headshells generally are those that are integral with the cartridge.... " ++++++
I respect your opinion but I have to disagree here, why?:
IMHO an integarted cartridge/headshell design preclude that we can find out which tonearm/headshell is the best match ( the cartridge examples you named were designed almost 40 years ago and between all those tears till today many things already change it on the whole subject. ) for that cartridge today shows us at its best even we can't test it in a fixed tonearm headshell design.
In the other side the internal wire/connectors inside that kind of cartridge designs are 40 years old and IMHO we today have better wire/pin connectors for cartridge mount: no doubt about.
There are other " problems " like in the FR where you can't change overhang or azymuth ( if the tonearm does not has it. ) or offset angle for testing different geometry tonearm/cartridge set up or for anything else.
I like more flexibility.
Regards and enjoy the music,
Raul.