how much power

Unless there is some very ugly quirk in the impedance curve/phase profile of the Vienna speakers, I'd find it hard to believe that the Denon's 125 wpc amp section will not comfortably drive them to levels well north of 75 db in an 11 x 15 room. As to available current and stability into the load, I seriously doubt that you have an issue with either.

It is certainly true that SQ may vary from power amp to power amp. Designs differ and different amps each interact in their own way with any given speaker's load, but that's a different kettle of fish. You may well prefer a different amp, but I highly doubt that you NEED one to drive your speakers to your desired levels.

Whatever else may be going on here, this set-up does not appear remotely underpowered to me.

Marty

Roxito, good thread. I am currently researching the same scenario with my bedroom system, which consists of a Yamaha RX-V1800 receiver driving a set of Monitor Audio Silver 9i towers. The bedroom is the master, and not small, at 14 by 16 feet. I think the speakers are rated 6 ohm, but may drop lower than that. The 1800 is rated at 130wpc into two channels. But it seems that if I crank the volume even to what I would consider a moderate level, the sound gets "glassy", loses clarity, and generally gets somewhat unpleasant to listen to. Could be increased room reflections, but I think there is more to it than that. Could also be speaker cables, which are Goertz MI-2 Veracity.

Magfan,
I'm with you, just didn't want to get into all the advantages of Magnepans and answer the OP's question as to why "he" "may" need more than 50 watts. If I listened to the Left Brain crowd, I would have never tried a Cary 805 (50/70 watt SET) on my Maggies. That would have been a loss.

No problemo. I used a Kenwood integrated for a while...with MG-1s. This was quite a while ago.

As to 150 watts and 45 amps? That's about 3.3 volts. Clearly something doesn't add up.
My panels are fused at 4 amps for mid/tweet. Figure 8 amps full tilt for the whole enchilada. Why would I need 45 amps? My Ice amps have some wacky spec like that which is IMO, nearly meaningless.

I would suggest that some scheme like this....linked, is a good place to start in any chat about amplifier REAL power into REAL loads.

http://www.audiograph.se/Downloads/PowerCube_12p_brochure_complete.pdf

'As to 150 watts and 45 amps? That's about 3.3 volts. Clearly something doesn't add up.
My panels are fused at 4 amps for mid/tweet. Figure 8 amps full tilt for the whole enchilada. Why would I need 45 amps?'

Well what does it all mean? Some very reputable companies always list this spec. Parasound and Harman Kardon come to mind. The bigger HK list 100 amps and the parasounds 60 amps. I have read some gurus that say amps are not even important. So I guess it's an audiophile thingy, i.e No answer. BTW, the link and the cube graphs etc.... are very similar to the method used to test amps in the Audio Critic. Better be careful. :)