Can a new amplifier affect speaker placement?

As spoken, system synergy, does play an important part in the sound you get. The 'system' is a chain, changing one part of the chain will change the overall result. The interconnects and speaker cable will always play an important part of the sound you get. So, the 'hobby' can drive you to frustration, especially when you realize a change has not produced 'better sound'. Do you have return privileges?

Years ago I replaced my amp with one that was three times the price and the lesser one sounded better.You can't go by price and power with this stuff,as a matter of fact I generally prefer the sound of lower power amps.Many things come into play like damping factor,type of output (I prefer fets)power into different loads,etc.I would try to return it because you will never enjoy it.

Another solution is get a small inexpensive subwoofer to supplement the bass. There are plenty offerings from SVS, SUNFIRE, PARTSEXPRESS, PSB, etc.

I'd give it some time to settle -- more than anything, in your own mind. Get used to the sound, and why it's different. (That is, unless you're looking at a return window in which you need to make decisions, but even then, give it as much as you can). When you say that the bass isn't as rich, what do you mean. Leaner, less boomy, tighter, faster, less extension, less textured, less energy...? Some of these things can be good thing, some of them less so. Could be that the amp is simply less capable of controlling your woofers. Could be that it is more capable, and that what you're hearing less of is actually a product of better control and more accuracy. Could be that, whichever it is, it really doesn't matter because you prefer the sound of the Creek. So, sure, can happen -- any of those things. Could also be that moving your speakers will give you better (or worse) results. I'd experiment with all that. And put in some time with the new one -- as much as you can or have patience for -- then switch back. I've always found that switch back to be the most enlightening moment regarding whether the change was worth it. Just my two cents.

+1 Mezmo.