[Hallicrafters] S-53 vs S-53A

[tlogan7 at cox.net]

Hi Folks -
I'm new to vintage radio and would like to know the difference between the
S-53A and S-53 receivers. Are these two models or do people refer to the
S-53A often as the S-53? Thank you very much for any help.

73/Tim NZ7C

PS Looking for an HT-18