I have a pair of 1962 AR-2a speakers - cloth surround woofer, dual mid, hard brown tweeter. I also have a pair of AR-2ax black 3/4" tweeters - could these be substituted in place of the hard brown ones without a crossover change? AR seemed to use essentially the same crossover for the AR-2a and AR-2ax, except the #1 lug on the mid potentiometer is not attached to the common negative speaker input in the AR-2a, but is attached in the AR-2ax. I suppose I could just get a pair of AR-2ax mids a