OK. I have a reputation here for being diplomatic. (yea thats right...) The Mackie amps work, and that is all I will say positive about them. They are far from great amps, but many people live with them. People also use Behringer amps. That doesn't make them great, just functional. If they are working for you, keep them. They have adequate power for your needs. If you want your 4719s to keep working, listen to what you were told by Roadranger.
All RMX amps are capable of 2 ohm loads per channel. However, non HD versions have been known to thermal when pushed hard. QSC therefore issued a coupld of HD amps. In each case they are derated version of a larger amp. The 1850 HD is a 2450 derated, and 4050 HD is a 5050 derated. While the 2450 and 5050 will both work at 2 ohms they can thermal if pushed hard enough. I have never seen a HD version thermal even when pushed. I know this because I had 1850s and 2450s at the same time. I tried using the 2450s for subs originally and a number of times I had them thermal. QSC advised me to go to the HD and told me of the derated design. After I bought the 1850s, I never had another thermal.
Is that tactful enough for you? I will never be this nice again, but you are new here so you get one. Roadranger knows exactly what the hell he is talking about. He has more posts offering others advice than you will have here for years and they are ALL usually quite correct. We may be willing to share info here with people that need answers, but that doesn't mean we are willing to take crap while doing it.
If you don't like the tone of the replies, don't ask questions. He gave you the correct answer in the first post of this thread. It could have stopped there.
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. What do YOU think the difference is between the 4050HD and the 5050? Or the 1850HD and the 2450?
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