Hi, Today I just bought a pair of Model 22's from a guy on CL. The cabinets are in beautiful condition and they sound great.   When I got home I realized that one is a 22 and one is a 22A.   He advertised them as 22A.    Does anyone know what the A designation is for and is there any difference?   I can find references online to both but no mention of the difference, if any. The tweeter on the 22 is mounted on a white cardboard ring, the tweeter on the 22a is mounted on a black plastic