recomending power to speakers

If the d-60 is tubed, then going to 4 ohms won't increase the power. You just have to switch to the 4 ohm taps.

Thiels, even though they are great, are not tube friendly and love lots of power. I wouldn't go with less than 100wpc. Keep in mind that you can't hurt these speakers with too much power but can kill them and your ears with too little power-distortion......

Need more info on your system and tastes to recommend a specific amp.

I have classe 20 pre, sony dvp s7700, music hall mmf5 TT, MIT T2 speaker cable, The Music Cable (best cable yet) IC's

I enjoy female vocals, rock, jazz... pretty much everything but heavy metal and classical...

Thank you,

much appreciated...

Try the 4 ohm taps first before you throw money at it. You also might have the amp checked out depending on its vintage as tube amps do require periodic service to replace caps, tubes, and so on.

I used a Levinson 27.5 with Thiel 2.2 CS speakers and never had a shortage of power. I believe this amp, or a Threshold pure cl
ass A model (SA3 or better), will work fine with your speakers.

These amps would do the trick with 200 triode watts per channel:
http://cls.audiogon.com/cgi-bin/cls.pl?ampstube&1132177886

If you want to stick with tubes look to a high powered VTL monobblock amp. A good friend, electrical engineer, used a pair of VTL tube amps for his Magnepan 3.6 speakers which require a TON of power to make them sing. I think they were the MB225 which run in triode mode. If you do acquire a VTL and it has switching between triode and pentode mode NEVER flip the switch when the amp is running; you may blow it.

i would keep the arc and ditch the thiels. go vandersteen, castle, klipsch, or one of many more musical(and 60w) friendly models.

Ditch the ARC. They are dry and lackluster with most speakers. If you insist on tubes go with high powered BAT, VTL or Manley. Good solid state amps for your Thiels are Pass or Classe. Krell and Bryton present the same dry sound as ARC so avoid them.