Marantz 1200 vs Marantz 1200b

I can't  seem to find any information on the Internet the explains the difference(s) between the Marantz 1200 and 1200b. Face plates and rear panels look the same, but there was a $105 list price increase.
Does anyone have any credible information? Parts upgrade, circuit redesigns?
rumor has it that:
The 1200 has the same driverboard as the 250 mk1
The 1200b has the same driverboard as the 250 mk2

Ah, yeah, Randy and  imhififan..........but getting back to the question....

WHAT'S the difference?
Please don't refer us to a manual.....which we clearly don't have.

And please don't refer to "circuit boards being the same as some OTHER device....which we clearly don't own".

Is there no one who has the simple know....sort of like the B model has 50 more watts output....or the NON-B model was produced in the late 70's vs the B model being produced in the early 80's?

Come on, guys; please don't make us chase our tails around the internet on this.