I'm currently looking for a B&K power amp to run behind my B&K Pro10mc preamp. I'm looking for the higher powered variety..... in the neighborhood of 200wpc @ 8 ohms. In looking around I see a few that seem to meet that criteria. EX-442, EX-4420, ST-3030...... and maybe there are others? Are these all the same basic amp (or not) ? Maybe different vintages? Is there anyone out there who can explain and also let me know if one is more desirable than the other ? Thanks in advance!