Cartridge burn-in

To be clear, I’m not saying that a bad sounding cartridge gets good once it’s broken in, although in individual cases that might happen since judgement is almost entirely subjective. I am only saying that cartridges that are either brand new or have been in long term storage audibly benefit from warmup. This probably has nothing to do with flat-spotting, a well known phenomenon that can occur with any car parked for more than a day or two on concrete or any very hard surface.

I think experienced vinyl users here have experienced two different types of cartridge break in and have noted a variance in need for break in depending on the design or model of the cartridge.  My SoundSmith MIMC star took a long time to start sharing the deep groove musical details while my Hyperion demonstrated greatness after 20 hours. Anyone who has used a new Ortofon MC A90 knows that bugger takes a long time (>100 hrs) to open up and play music. 

The other type of break in is what @lewm ​​​​@mijostyn are referring to.  I call this the "Lyra one LP side warm up", the time it takes for my friends Atlas or my Etna to start sounding its best.  I think Lewn's use of a test LP is a great idea to warm up a cart.

On the original Cardas LP, bands 2a,b, and c encode wide frequency sweeps that are ideal for this purpose. That’s on the original 33 rpm version of the LP. The current version is at 45 rpm on side 1. I use tracks 1,2, and 3. (I own both the older and the new versions of the test LP.)

i am not sure whether Mijostyn agreed with me or not.

The only item in the assembly that is looking likely to need to show a change that is perceived as adding an improvement through the change is the Material used for Damper.

A Change to the Stylus is potentially wear only and this will be deemed detrimental as it progresses.

The Cantilever and Pivot are certainly not parts belonging to the assembly that would be wanted to change their inherent properties.

The Damper is a material that is a Compound of materials that will ultimately become a Type of Rubber, the constituents/formulations will vary to produce the Rubber Compound. Designers will select a substance that in many cases will be a unique material, that satisfies the designers need for the elastic and viscous properties of the material, and possibly the known environmental effect on the Compound.

The Rubber Compound selected as the Part, can have a multiple of ingredients and these can vary in the parts added per 100 parts of rubber. The final selection of the Rubber Compound and effects on the Compound of the added Elastomers will undoubtedly produce a Part, when selected that is to have a multifunction role.

One such role which will be for the managing of vibration will be best served from a Compound that has the correct Static and Dynamic Properties engineered into the Rubber Compound. Knowing such information will be critical in the selection process.

It does seem that a Damper is to change its properties through usage and possibly time. It does seem a most likely Damper Selection will be limited to a selected few, who will be qualified in making the choices for these changing in properties materials. 

It does seem a Damper has the potential to be impacted on by the environment it resides in, and through usage can change. It also seems likely a Damper that has been exposed to the environment/working environment for a long period can possibly undergo changes that become detrimental to the Cartridges performance. The question is do Dampers from a production have a uniform property or is there variances across samples, or is there Dampers used that might already be affected by the environment they are kept in. Is this a possibility a Quality Control issue and is contributing to the differences reported for Break In times. 

It is possibly a selection of a Damper Material, that is one, that can make or break a Design and how it is received in the Market Place, so a very big responsibility to get it correct for the end user. Keeping a Damper material as stock item for an extended period in a particular environment might have an effect on the material and change the performance of product as it produced over a period of time.

The Suspension is one I am not sure of, it is known to change its properties through usage, but I am not sure where the detriment to the overall performance manifests due to these changes. It is not uncommon to see a report where a Suspension required re-tensioning, the question is does the tensioning vary between models when new. Is this a quality control issue and can possibility be contributing to the differences reported for Break In times. 

@lewm, flat spotting will occur in high performance tires if left parked for 30 minutes. As the tire cools down it hardens and loses traction. The colder the ambient temperature and the surface the tire is on the faster this occurs. This why tire warmers are used in racing. A cartridge's suspension undoubtedly heats up to some degree and obviously at rest it cools down in a position other than what it is in while playing a record. A theory based on assumption. May not be true at all but it is imminently plausible. On the other hand, I do not hear it. I did not hear the MSL change at all during the first 50 hours but @sksos did in an MSL that is almost identical.  So either my hearing is not good enough to discern the difference or break-in is a psychological phenomenon. Take your pick. I think you would agree that if a cartridge breaks-in the difference between new and say 100 hours is not night and day but incremental at best.