Is powerfull Amps only for low sensitivity speakes?

Thank you very much for your valuable feedback Al.
regards, 
ozan

obatu
Is powerfull Amps only for low sensitivity speakers?

Obatu, don't just get caught up in the amount of wattage needed for the sensitivity. Yes this is important, but only half of the question/answer. As you have impedance also to deal with as well as negative phase angle. These mean how much current is going to be drawn from the amp, not just the wattage.
EG: As you can have a pair of speaker like Wilson Alexia which will be driven to sound far better with a 25w ML2 monoblock than a 1000w amp that has not much current ability.  

Cheers George 

But...SET/DHT amps using tubes like 2A3 and 45s in these flea amps can sound so much better than a 300watt bank of transisters.

I hope you can listened to the GS150 in your system first before buying" what is it you don't like about the Accuphase A60 anymore.

This "more power is better" jazz is pretty sophomoric advice. Watts are practically irrelevant. The two questions one needs answers to are "Does my speaker need a current source or voltage source?" and "How far are you listening?" Benign, high impedance loads tend to do better with amps that provide disciplined current. Reactive, low impedance loads do better with voltage sources using some feedback. Then you have to consider the behavior of the topology and class. It’s WAY more complicated than watts.