Phantom + A90 question

Nice pic, Tobes. I'll relax about mounting the A90. Seems like a non-issue. Thanks.

I doubt contact with the third ridge would have altered the sound - at least with an arm having easy azimuth adjustment like the Phantom.

With resolving components like this, changes in cartridge/headshell contact always alter the sound - even when azimuth remains constant.

Don't take my word for it. Try changing your mounting screws from stainless steel to brass to nylon - without altering azimuth or any other parameter. I guarantee you'll hear differences.

Think about how a phono cartridge works: anything that vibrates the coils or magnets generates a signal (or alters a signal being generated by other vibrations, such as those induced by record groove modulations). Stray vibrational energies within the cartridge body feed back into the armature and magnets, distorting their movements and therefore distorting the original signal. So, changing the behavior of these energies will alter the sound of the system.

The behavior of stray cartridge-body vibrations is heavily influenced by cartridge/headshell contact, as the screw material experiment mentioned above easily demonstrates. Altering the number, size or placement of cartridge/headhsell contact patches also alters those behaviors. Ortofon chose 3 contact points because they believe this cartridge sounds best this way.

I've no idea if Ortofon was right, if 3 contact points sound "better" or "worse" than 2 or 4 or a flat surface - but I guarantee they'd all sound different.

Doug, you may be right but its not something I ever lost sleep over when I used the A90 with the Phantom.

The A90, and other similarly designed Ortofon cartridges, actually have 5 contact points when you think about it - the 3 raised ridges + the 2 fixing bolts.

I agree that every small change makes a difference with analog. Some are for better or worse. Some are just different and it could be argued either way depending on the ear of the beholder.

I suspect the OP's suggestion of a mounting plate would sound more 'different' than omitting the 3rd ridge (since it introduces another material/interface) - but only the ear could decide which is preferable.

I've just finished a nightshift and my thinking may be faulty but....

I seem to recall that the idea behind the ridges on the Ortofon MC's was to allow for azimuth adjustment on arms that didn't provide that adjustment - ie tightening bolts such that the cartridge canted either side of the central ridge.

This would be tedious in the extreme to actually achieve proper azimuth, but in any case, wouldn't tightening towards one side inevitably lift one of the rear ridges away from the headshell?

Interesting idea, although a single ridge on the centerline of a cartridge is superior for azimuth adjustment, as it only allows the the cartidge to rotate about one axis. I've used that method on tonearms which lacked azimuth adjustment. It wasn't any more tedious than using the adjustments on some tonearms, though other arms make it easy of course.

My guess (only) is that Ortofon wished to minimize contact between cartridge and headshell for resonance control reasons, rather like the 3-point Mapleshade isolator, and didn't consider the quirks this might present for small headshells like the Phantom's.