Good partner amp for Egglestonworks Anda II


Hello everyone, I was lucky enough to get a used pair of Eggleston Andra IIs for a good price, so far I'm loving it but I'm getting people telling me that the Andras are hard to drive and that i should upgrade my amp.

Although I'm quite happy with the Andras on the Mcintosh 275, I recently heard my previous speakers the Dynaudio c1 hooked up to kilowatt monoblocks from Bryston and I was amazed at the difference in drive and dynamics the Brystons made.

Now it's got me thinking if I'm maximizing those four 12 in woofers, obviously not right? I was hoping some of the more experienced forum members or other Andra owners can give me some advise on a power amp that's well suited to the Andras, I'm also willing to consider an integrated amp and I was also wondering if I should consider passive bi-amping since the Andras are bi-wireable. Thanks in advance.
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If Eggleston has not done anything weird to the Dynaudio Esotar tweeter, I think Spectron will be a good choice. Spectron has superb transparency and extension, something I find complements well with Dyn Esotar like Dyn C5 and SF Extrema. Comparing Spectron to McIntosh MC501 is like lifting a veil, I even prefer Spectron over Pass X350.5 in most cases.
I am using a BAT VK600SE with Andra IIs. I have also run them with a DNA-500. My room is 14 by 18 ft.
There is a ton of bass energy available from those 4 12" woofers. Why not take advantage of it all?
Thanks for all the suggestions, one thing I'm convinced of now is that they do need lots of power, does anybody have any thoughts on class d amplifiers, any brands out there have synergy with Eggleston house sound?