Dear @lewm @celander : A tonearm muyst be an inert device but no single tonearm out there is inert. Designers try to design tonearms well damped many with out success and other choosed for no damping at all, these ones are the worst no matter what.
What is happening with OP cartridge is not only for the Decca London but any cartridge signal will receives dramatic benefits that only a deaf man can't listen.
When Sumiko puts in the market an arm pipe device was because they made it several tests but my first hand experiences with over 15+ tonearms and dozens of cartridges told me and tells me that Sumiko was rigth.
Lewm, you always think on theories or just imagination on subjects as this one. Do it a personal self favor and test it and you will see that always makes a difference for the better. Test with the 3M 434 that will mantain almost the same inertia moment/EM.
@celander , the headshell you bougth is not well damped and that's a problem not only for your cartridge but for any one.
The arm pipe of your tonearm is made for a well self damped magnesium material, try with these magnesium ( that match the toneam magnesium material. ) very well damped headshells and you will confirm what I said about:
https://www.ebay.com/itm/AUDIO-TECHNICA-HEAD-SHELL-AT-MG-10-from-JAPAN-Japan-new/183366770516?epid=2...
https://www.ebay.com/itm/Audio-Technica-AT-LS12-headshell-with-adjustable-azimuth/302816656736?hash=...
https://www.ebay.com/itm/Audio-Technica-AT-MS9-Headshell-adjustable-azimuth/113137039830?hash=item1a...
https://www.ebay.com/itm/Audio-Technica-AT-MS10-Headshell/223092162897?hash=item33f1544151%3Ag%3ABhE...
https://www.ebay.com/itm/HIGH-QUALITY-AUDIO-TECHNICA-DISCONTINUED-MAGNESIUM-LT12-PHONO-HEADSHELL/263...
R.
What is happening with OP cartridge is not only for the Decca London but any cartridge signal will receives dramatic benefits that only a deaf man can't listen.
When Sumiko puts in the market an arm pipe device was because they made it several tests but my first hand experiences with over 15+ tonearms and dozens of cartridges told me and tells me that Sumiko was rigth.
Lewm, you always think on theories or just imagination on subjects as this one. Do it a personal self favor and test it and you will see that always makes a difference for the better. Test with the 3M 434 that will mantain almost the same inertia moment/EM.
@celander , the headshell you bougth is not well damped and that's a problem not only for your cartridge but for any one.
The arm pipe of your tonearm is made for a well self damped magnesium material, try with these magnesium ( that match the toneam magnesium material. ) very well damped headshells and you will confirm what I said about:
https://www.ebay.com/itm/AUDIO-TECHNICA-HEAD-SHELL-AT-MG-10-from-JAPAN-Japan-new/183366770516?epid=2...
https://www.ebay.com/itm/Audio-Technica-AT-LS12-headshell-with-adjustable-azimuth/302816656736?hash=...
https://www.ebay.com/itm/Audio-Technica-AT-MS9-Headshell-adjustable-azimuth/113137039830?hash=item1a...
https://www.ebay.com/itm/Audio-Technica-AT-MS10-Headshell/223092162897?hash=item33f1544151%3Ag%3ABhE...
https://www.ebay.com/itm/HIGH-QUALITY-AUDIO-TECHNICA-DISCONTINUED-MAGNESIUM-LT12-PHONO-HEADSHELL/263...
R.