My system consisted of Cambridge audio c500, 2 p500 (biamped) and b&w 602 s3. I'm completely happy with it but read so much about how nad's are ideal w/ b&w's that when i saw a used one for sale that i snapped it up.
1st thing i gotta say is that the nad did not blow away the ca's. I listen to small jazz a lot and so far the ca's sound so much more intimate with that kind of music, while the nad does sound more suited to rock.
The point of this thread is that i notice when i biwire the nad (2 wires to each speakers with the binding posts taken off on the speaker, and turn on both speaker A & B options on the nad) i hear an unbelievable differnce. More so than when i bi-amped my ca's. THere's way more bass... wired normally on the other hand, the nad is totally missing the low ends compared to the ca's. I'd be willing to consider the biwired nad over my ca's, but definitely not a normally wired nad.
But i'm thinking that there's more behind this unbelievable difference. I asked an engineer/audiophile friend of mine about this and he told me that he thinks because when i turn both my speaker A and B on, it's running in parallel, and therefore my 8ohms speakers basically turn into 4 ohms speakers, thus making the c370 send more current through, thus giving me this huge bass improvement. However, he warned me that i was overextending the nad by doing this and this would lead to a shorter lifespan.
I used to have B&W 602S2 biwired to a NAD amp for years and it made a huge difference. I don't remember using both speaker terminals from the Amp. Maybe I used only one. Anyway, isn't NAD supposed to adjust to the speakers impedance automatically?
Actually, i think you're right. I just read that nad has ISC, "RMS out- put power remains the same at 120 Watts with either an eight or a four ohms load. "
But if that's the case then why the big difference? It doesn't make sense. I don't get this difference on my Cambridge Audio's, and from what i've read on the web, i shouldn't be getting a difference this big.
I checked on a dutch HIFI site and the expert there says that you can connect the cables to both the A+B terminals and switch both on (otherwise you'll hear only high or bass) I'd ask NAD as well, they usually respond fairly quickly to questions.
This is embarassing but i came back home to hear the difference one more time b/w normal wiring and biwiring, and i don't hear such a big difference anymore.... i'm not sure what happened... i'm afraid i might be imagining things.
On another note, i'm willing to give my take on the Cambridge Audio's versus the NAD if anyone will still trusts my ear....
The first day i was comparing NAD to the Cambridge Audio, i wasn't blown away. I noticed that the music coming out of the NAD was more defined and had more depth, but i was still seduced by the CA's brightness and detail (maybe wrong terms?). THe NAD sounded better w/ rock, but the CA's just sounded more intimate with small jazz. Jazz on the NAD sounded like i was listening in a concert hall, while on the CA"s fuller sound made it more like a small club. As well it just seem to me the NAD lacked the bass of the CA's.
Day 2, i tried a jazz track with just piano and bass.... perfect cause i can just concentrate on sound with these kind of tracks, not be distracted with too many instruments. And suddenly i noticed that the CA actually was not as defined/tight on the bass, it was boomy, while the bass from the NAD was actually really tight and defined. In addition, The instruments just sounded more real on the NAD. I started listening to the tracks from the day before, and with my new revalation, i started to prefer the nad much more.
Now, just for kicks, i tried the Cambridge Audio C500 preamp with the NAD, using the c370 just as power amp. All i can say is wow! Voices with this combination are just more natural. On the NAD alone, voices sound like the singers are singing through a filtered microphone, i think this is why the nad sounded like i was in a concert hall vs a small club in day 1.
I'm definitely keeping this setup! Huge improvement! I just love the sound of my system now.
Quote "But i'm thinking that there's more behind this unbelievable difference. I asked an engineer/audiophile friend of mine about this and he told me that he thinks because when i turn both my speaker A and B on, it's running in parallel, and therefore my 8ohms speakers basically turn into 4 ohms speakers, thus making the c370 send more current through, thus giving me this huge bass improvement. However, he warned me that i was overextending the nad by doing this and this would lead to a shorter lifespan."
I dont believe that simply birwiring your speakers is going to change the impedance load on the amp significantly: it doesnt matter whether you connect both cables to one set of speaker teminals onthe amp, or the A and B terminals; the effect is the same.
However, if the impedance were to drop, then yes a higher current would be delivered, but this would not improve the bass. It would probably make the sound worse, since you might be running the amp close to its max power output and into the stages of compression and ultimately clipping. If anything, the bass would be less dynamic and less clear. The reason why amps such as Krells follow a huge power rating strategy is the belief that the amp can worl well within its enevlope, therefore reducing the effects of dynamic compression.
J Vigne can probably comment on this more authoritavely than I can.
As far as I understand, there is no difference in the amplifier load whether speaker wires are connected to the same post on an amplifier, or put into A and B speaker posts with the both pairs switched on (and since I still remember something from my first education as electronics engineer, I can claim some authority here). I.e. connecting low and high frequency circuits of a speaker to A and B speaker posts cannot be damaging for the amp.
Nevertheless, while I've been always quite sceptical about bi-wiring because I didn't see why it would make any noticeable difference (the change in the characteristics of the active load of the amplifier is miniscule given the low impedance of the speaker wire), I decided to experiment and indeed my NAD c372 with Mission 783 speakers seems to sound better with bi-wiring - the lows seem to become more pronounced, and the midrange appears to open...
