Audiophile opinions sought (power amp or not?)

[Woz]

I've just ordered a NAD C370 amp to replace the NAD C314 I'm borrowing from a friend.
I'm currently using the 314 in power amp mode (you can pull two connectors on the back and disconnect the pre-amp stage on all NAD integrated amps). This is nice and convenient and has definitely improved the sound from the system. The system is as follows:
Sony 725s DVD
Yamaha A5 (being used as a pre-amp and processor)
NAD c314 amp being used as power amp
B&W DM 603 S1's front.

The question is, should I use the 370 in the same fashion? It has a class A pre-amp section, so it would be a shame to waste it, but the convenience of a single volume control is tempting (and wouldn't confuse the other members of the family!).
Anyone have any opinions on what sound improvement would be either way? The Yam makes an audible "Clonk" when it switches to analogue CD, so it's using a relay, and not an electronic switch, so it may not be colouring the sound too much.

Just wondering prior to delivery :D

(by the way - I'm getting it from Richer Sounds for £100 off - they had 5 in their warehouse - ex-dem models, but being as they don't normally market this amp, I can't imagine they've been demo'd much).

[Bapapapa]

Listen to it both ways and see what it sounds like. Depends on how much you & especially the missus values the convenience of having a single volume control, I suppose.

If the Nad sounded significantly better I know what I'd do.. :D

How much was it mate?

[MikeK]

There won't be any improvement at all by using the NADs preamp, unless you cable some analogue phonos from the 725 to the NADs CD input, and use that for CD replay. Even then it depends on whether the 725 has a better DAC than the A5.

If you just connect to the A5 alone via a digital cable from the 725, then you are already going through the Yamaha preamps, so then feeding it through the NAD preamp, even if it's significantly better than the A5's won't matter, as any signal degradation in the A5 preamp will already have taken place.
At best the NAD preamp may not add any further degradation, but there's also a chance that it may - the less preamps etc that a signal goes through, the less can be polluted or degraded or whatever you wnat to call it.

[Bapapapa]

MikeK - I'm assuming the 725 is connected via analogue for CD replay.

"The Yam makes an audible "Clonk" when it switches to analogue CD,"

I'd expect the NAD to blow the Yammy away for CD replay.

[Woz]

Thanks guys.
Yep - I've currently got highish quality phono interconnects running from the 725 to the Yam and the 725 certainly has much better DACs than the Yamaha for CD. The Yam is currently being used as a pre-amp with the 314 being used purely as a power amp.
I do intend to try it for myself, but I do wonder how much the yam may be colouring the sound considering that it's using relays, so is hopefully keeping the signal path short and away from all that horrible DSP crap! It's just the lure of Class A Pre-amp that is tempting me. And the wife and 4 your old that are putting me off!

(I've paid 350 for it Baps - and I know- I've since seen it brand new (not demo) from QED for 370, but I understand that the condition from Richer will be superb and I get to take out their warranty, which seems the best on the market to me).

(by the way - if anyone is interested - I got a very significant improvement in sound quality by using the NAD 314 as a power amp on the Yam, and I would consider it an upgrade worth looking at for people who are after better music, but are happy with the movie side of things).