[Boatanchors] 6DQ5 6DQ5A difference?

[hwhall at compuserve.com]

Hello,
Does anyone have specifications that indicate the difference between the 6DQ5 and the 6DQ5A? I have not been able to find anything on that. My RCA manuals don't even mention 6DQ5A & google seems to come up blank too.  I'm suspecting maybe a bit more plate dissipation or better mechanical stability but would like to know for sure.

Thanks & 73,

Wayne
WB4OGM