Mac MC60s enough power for Apogee Centaur Minors?

hi all,

just joined. i need your collective opinions. i'm not nor can i afford to be a really high end audiophile, but i have ammased a decent system (according to my ears) over the years.

for starters, here's my current set up:

McIntosh MC60 tube monoblocks
Conrad Johnson PV-1 preamp factory modded to PV-2a specs
Apogee Centaur Minor ribbon speakers
powered B&W subwoofer
Rotel 930AX cd player
Adcom ACE515 AC line enhancer (whatever that is - $15 at a garage sale)
Technics SL-1350 turntable - broken
cheap interconnects and speaker wire

my question is that the apogees seem fine on the 8 ohm tap but sound absolutely glorious on the 4 ohm tap. problem is that the macs start to strain on anything above a comfortable listening volume )not that i blast it). which is fine, but i'd like to kick out the jams every once in a while ;-)

so, is there anyway to get the macs a little more of a fighting chance against the apogees. maybe more filtering. right now, i just have the stock power supply. i used to run my old MC225 with 900 MFD of filtering on the front end and it helped a lot. but, then again, i never heard a stock MC225 on my apogees.

OR, should i just keep the apogees around as a fun toy and look for more efficient speakers? they do sound really nice though. again, on the 8 ohm tap, i can get higher listening volume, but not the silky warm sound as i do on the 4 ohm tap.

someone said that the adcom line conditioner might be the problem. something about the VA rating and to get the macs of the it. i'm a total benchracer and do not know much about electronics, but have lots of audiophile friends that do.

see ya,
Robby