Cartridge burn-in

While I am a firm believer in "breaking in" most new gear, it is hard to quantify. It's hard to know how much of it is the gear itself changing character over time and your own ears becoming accustomed to what it's hearing and also not hearing. That being said, the two cartridges that I have had that used shibata styluses definitely felt thin and less dynamic until I played through them for a while.  

I took a rebuilt Cart' to a friend, to use in their system and compare to their owned Cart'.

My friends Cart' was with a decent period of usage hours and was a model that was from the upper range of what the Brand offers.

My own Cart's was a lower down the range model but bespoke produced through a rebuild.

The interest was to see where these two Cart's were in comparison to each other.

I distinctly recollect the first visit with 20+ hours of usage on my owned model, the Bass was not quite gathered and not quite able to create a perception of believable envelope for notes from the lower frequencies.

At a visit with about 150ish hours of usage, my Cart' was to my assessment a much-improved performer in the Bass region and a very good comparison to the friends Cart'. I also distinctly recollect upper mid and top frequencies were projected further and detail retrieval from the Groove was more evident.

I was not wanting much more and was not pining for anything else that been heard during the demonstrations. 

Improvement was expected to be discovered after a period of Break In, that was the general overview, and not too different from contributions from other posts within this thread. 

Improvement was discovered to be occurring, but the unexpected was for it to become an improvement to the point it compared very favourably to another rated model, this was not anticipated to end up as such a close call. 

To get to this point, it was only important to use the Cartridge in a very careful manner. 

Reason why manufacturers might not want to do "break-in" in advance of sale:  Because, in my experience, no cartridge is happy just sitting around, whether as a freshly built virgin in a sealed gift box or on the end of a tonearm.  In both cases, the suspension, which has either never been worked or has stiffened up from lack of use, benefits from use, which is why I recommend playing a suitable test LP in advance of a serious listening session, if the cartridge was not in regular use prior to the session and especially if the cartridge is brand new.  I specifically recommend the Cardas test LP, but there certainly may be others suitable to the job.  Sometimes I don't have the patience to use the Cardas LP in advance of a listening session.  In those cases, one can easily hear that the cartridge gets much happier after 20-30 minutes, if you are intimately familiar with the system and the SQ of the cartridge.

A pretty decent experiment would be to take one cartridge that has over 50 or over 100 hours on it, and then get another brand new cartridge (the exact same model), and play the two side-by-side on the same turntable, same tonearm, same setup, same phono, same preamp, same amp, same speakers, same room. That should tell us if there are audible differences between the cart that is broken in and the cart that is brand new out of the box.

To make that experiment more 'objective', the listening test between the two cartridges should be blindfold. The listeners must not know which cartridge is playing when. They are to make notes after listening to each cart, and then compare notes with the layout of the experiment.

Who's game?

No matter how you design your experiment, unless you are willing to spend money to do it, the design is fraught with sources for error that could skew the results.  If you compare a used or broken in cartridge to a new one, then stylus wear could be an issue.  If you set up the two cartridges in the same tonearm, then there can be error in set-up that could affect the results.  But the experiment is unnecessary in my opinion; it is very obvious and logical (given that the suspension is so important to performance) that break-in for a cartridge is real.  However, if you are skeptical, go for it.