So, I decided to start my first HT system with this integrated amp, but I am not decided yet with wwhich speakers should I go. I am thinking to PSB 4T or 5T or to Ascend Acoustics CBM-170. What is your opinion?
I've got a C370 amp running Kef Q5 floorstanders and I thoroughly recommend the end product - the Kefs blend perfectly with the Nad sound. I haven't tried either of your preferred choices so I'd recommend you audition them with some Nad amplification to see if you like what you hear. Ultimately which speakers you choose will be down to personal preference. You'll find that with the C370 amp you can drive ANY speakers so the world is your oyster!
ooops sorry, The Kef Q's would go well with the NAD-C370. rightfully so an audition is in order while you are in the process try to hear the Triangle Stratos series if it's available.