Can denon 4308ci be used as preamp for NAD M25 amp?

Yes that won't be any problem at all.

Daniel.

Absolutely!
http://www.homecinemachoice.com/node/6453

But it's hard to say if you will have an marked improvement over the AVR4308's amp section. It really depends on the speakers, room size and acoustics. You've given us very little to measure.

But to answer your question, yes, the NAD M25 will work with the Denon.

If your heart is set on the M25, go for it, but there are many other less costly amps available that will give the virtually the same sonic performance, if not better. Just an opinion.

Regards.

Hello gimli100.

I did receive the PM, but I will respond in the thread so others can chime in and give different prespectives.

20 x 25 room and Polk Audio LSi's you say? At 4 ohms, the M25 is very powerful @ 255w per channel. IMO, the M25 will be beneficial, especially in the long run. With that size room, the Denon is effective but you may experience fatique over an extended play. The NAD give you consistent performance over the long haul. Are you using the LSi's internal subs fo your low-end or are you using a stand-a-lone sub? That can make a difference in performance and sound also.

Regards.