Do MC's Need Time To Wake Up?

I know this is gonna sound silly, but what the heck. Has anyone here ever noticed the output level of an MC cartridge increase some time after installation? I've had this feeling before with several carts, but the differences always seemed very small. So I chose to discard it as some sort of psychological adjustment on my part. As if I needed to wake up to the change of sound.

But today I took delivery of a Jan Allaerts MC-1 cartridge. A previously owned sample, but coming from a reliable source and not having been used for quite some time. This MC-1 (the basic ECO version) reportedly has ca. 0.5 mV output, but at first play it required the same volume level as the 0.25 mV Entré EC-30 it replaced. But after playing a few sides I had to turn down the volume several steps to maintain the same sound pressure. This time there's no way I'm fooling myself. Or am I?

Does this sound familiar or should I just put it in the X-files?

I agree that MC cartridges do you need time to wake up. They need time to wake up if they are brand new or have very low hours on them, and they need time to wake up if they have been sitting around and not used for several weeks or more. I am not sure that this is not also true of moving magnet and moving iron cartridges, but I haven’t made the observation on the latter types.
Dear @edgewear @lewm  :  Agree all cartridges need " wake up " time even the one we use day by day but that wake up is mainly for the cartridge suspension not for its output level.

Of course that if in any cartridge the suspension is not yet settle down all frequency ranges will be unbalanced in between and when settle down we could listen that ( example ) high frequencies ( or any other frequency range. )  are louder but in reality are not louder but perhaps with more clarity/transparency or something like that but overall SPL/cartridge output in theory can't change with that " wake up " time. 
Is only our perception the one that changes.

Regards and enjoy the MUSIC NOT DISTORTIONS,
That Jan Allaerts MC-1 cartridge is a pretty rare bird. Enjoy it.
With a cartridge that has settled in ("broken in" sounds so drastic), I find that it takes at least a couple of sides for it to limber up and show its stuff. I’m currently using a brand new Koetsu stone body, and though it sounded surprisingly good out of the box, it needs several sides to start sounding like it should. I don’t think this is voodoo. The elastomers in the suspension need to loosen up (what effect does room temperature have?), and if the cartridge hasn’t been played for a while, I could see it making an even bigger difference from a cold start, compared to a cartridge that is regularly in use....
PS: I never regarded this as a matter of  'output' voltage or whatever but I suppose that could be part of it too. 
Yeah my Koetsu with enough hours to be considered fully broken in still sounds a lot better the second side than the first. Even when played the night before. Also continues to improve beyond that. Although I would say the first initial improvement is a lot more obviously the cartridge. My system always continues to sound better as the night goes on, though you got way too many contributing factors to say its all the cartridge.

Also while it does sound noticeably better its better not louder. I've never noticed any increase in output. In fact, usually if anything quite the opposite. Not in terms of volume, but because the sound when cold is somewhat grainy and hard which makes me want to turn the volume down. This was the case as well with the Benz Glider and Ruby I had before the Black.
Thanks for the feedback. I guess we all have had our fair share of 'settling in' phenomena. But the first encounter with the Allaerts was of a different (third?) kind. By now it has 'settled' and the output is stable. For my usual NAF (Neighbour Acceptance Factor) friendly listening volume the display on the amp is at -50dB. Initially I needed -45dB to get the same SPL, no kidding!

It's still early days, but sonically the JA is quite interesting. I installed it in my Audiocraft AC-4400, loaded at 100 ohm as specified. This appears to be a good match and it tracks everything with ease. For testing I always use the George Crumb Makrokosmos Volume III LP (on Nonesuch) for its enormous dynamic range and those crashing cymbals and gongs.

The tonal balance is on the warm side and it throws a back-to-mid hall perspective. You might think this would put it in the 'polite or boring' camp. Yet sudden crescendos jump at you like a force of nature. It doesn't have the usual (and often tiresome) high frequency rise of most modern MC's, yet the high register is wide open and sparkles without drawing attention to itself.

The JA has a - presumably deliberate - visual likeness to Belgian chocolate 'bonbons', which can also take you by surprise with what's inside.... To my ears its closest sonic relative is the Myabi, which is high praise in my book.

And this is just the basic MC-1 ECO model with fairly normal specs. The higher MC-2 models have unbelievable specs (like 70dB channel separation and amp like distortion figures), but the prices are also unbelievable. I'm curious if anyone heard these and compared them to the ECO?

When I first installed the Hanna EL the voices were to large for the rest of the music , and more than one set of ears was there to hear it. But arter some time maybe 15 to 30 hours  of play ,everything sounded  good .
Yes I think it is true