[Heath] SB-110 vs SB-110A

[George Babits]

Can anyone tell me the differences between the SB-110 and the SB-110A. 
According to the front bezel, mine is an SB-110.  The manual I have is for 
an SB-110A.  I note that there are a couple of 6AZ8 tubes where the SB-110A 
manual calls for 6AX8 tubes.  Any other differences?

I spent a lot of time a couple of years ago trying to get this working.  As 
I recall, I had the receiver working very well but wasn't getting much out 
of the transmitter.  Finally think I have time to get back to work on it.

Thanks and 73,
George
W7HDL