Power amp + CDP: is that enough?

It depends on the max output voltage of the CDP and the sensitivity/available power of the amp. If the CDP can drive the amp to satisfying output level; you'll be fine, and will avoid whatever colorations a preamp might add. YES: try it!

I think the Sony has a digital volume control... basically, to cut the volume, it will start truncating the information. So, although a good idea on paper, you will lose detail and quality... Also, the Sony has no way to adjust the max volume output (you always want to stay towards the very top end of the volume if you use a digital volume control).

I think there is a lot of misinformation being spread around about digital volume controls. They are not all created equally. I personally think my Wadia 121 DAC with volume control sounds better direct to the amp, for example, and many others agree. I can't speak to your Sony, but the only way to know for sure is to try it.

Thanks! I don't think my vintage Sony CDP-770 has a digital volume control; the volume button actually turns when I press the remote. Great sounding CD player, BTW; that's why I stick to it.

So, it's a matter of exprimenting with power amps. Will try. Thanks for the advice.

Rrog has summed it up nicely. I've had a Sony XA7ES player and tried driving the power amp directly, bypassing the preamp. Although the sound is cleaner which gives an impression or illusion of a purer sound with higher levels of refinement, there is just something missing in the music. The dynamic shadings are somewhat missing, the punch and drive in music. In other words, music sounds a bit flat.

I've managed to listen to a high-end DAC driving a Krell FPB amp directly at a friend's place, a dCS Debussy. We A/B'd between running the DAC directly and having the preamp in the chain. Although the DAC gave very good results driving the amp directly, producing a transparent and almost faultless sound, the same phenomena still applies. Having said that, I can probably live without the preamp with the dCS Debussy. The preamp brings a tiny bit of involvement into the music, small but appreciable.

In summary, with the Sony CDP, for the best results I feel it's best not to drive the power amp directly with the internal volume control of the player, though there is no harm if you want to try and see how things work out for yourself.

Cheers.