NAD C740 & NAD T777 biamping

[bri]

Interconnection help please. I'm upgrading from a stereo system to home theater. I want to bi-amp my monitor audio silver 8i(s) front speakers. I"m using a NAD C740 as a stereo receiver now, and have a new NAD T777 A/V receiver ready to go. So how do I employ both amps in a bi-amp fashion. I have blown-up detail drawings of both NADs back panels and havn't figured the interconnection wiring out yet. Can anyone help??

 

[markw]

This might work if you can use both the preamp outs and the internal power amps in the 777. If not, then you're out of luck.

Yes, your 777 has the required preamp outs to feed an external power amp. That would handle 1/2 your biamp needs

Yes, (I believe. I didn't check) your integrated has the power amp inputs needed to access it's power amp. If not, you might be out right there.

But, if your 777 can feed both an external amp AND it's internal power amp simultaneously, that's your second power amp and you're in business.

If it can't, I cannot see where your 777 has power amp inputs, which would be needed to feed the signal back into the 777 for the second power amp.

You might want to check your manual on this.

Are the gains on the two different amps comprable?

 

[3db]

Why do you want to bi-amp?

 

[bri]

Would you advise against it? Would sonic benefits not occur?

 

[bri]

Thanks- Working on it.... The NAD T777 has 7 SPEAKER A inputs. My system will have 5. IF I could reassign the 2 unused speaker inputs from, say, R&L SURR-BACK to one of the bi-amped fronts----IF the 777 can be configured I would't need the C740?

 

[3db]

Basically, that would be my stance, no sonic improvement unless you're wroking with really thin speaker wire over long distances. If not, bi-amping will not give you an audible improvement.

 

[bri]

Thanks. All I'm trying to do is get all my audio/video source components inputed into the 777 sonically outputed to the 5.1 surround system, a pair of outdoor speakers, and two sets of basement speakers. I have the C740 to do this if I need it.

 

[BrettH]

"Thanks. All I'm trying to do is get all my audio/video source components inputed into the 777 sonically outputed to the 5.1 surround system, a pair of outdoor speakers, and two sets of basement speakers. I have the C740 to do this if I need it."

I've been doing quite a bit of research on biamping, as I recently got a pair of B&W 685's (that I'm thinking of upgrading to CM8's) that are biamp capable.

There are actually three routes you can go - biwiring, passive biamping and active biamping. From what I've been reading, there may not be much, if any, improvement from biwiring and passive biamping, but active biamping is supposed to provide improvement to speaker response.

In biwiring, you are actually attaching two speaker wires to the same terminals on your amp and connecting to the two different posts on the speaker. Since the same signal is going to each terminal on the speaker, most of the information I've seen suggests that the only real improvement from this is that you're effectively increasing the signal strength, and you can probably get the same result from just using a thicker speaker wire.

In both passive and active biamping, you're using two different amplifiers to send signals to the LF and HF terminals on the speaker. In passive biamping, you send an identical signal to the LF and HF side. This means that the bass driver is getting the entire frequency signals, and so is the mid/treble driver. From what I've read - and it makes sense - you don't get much improvement from this as you still need to rely on the crossover circuitry in the speaker to filter out the extraneous frequencies.

In active biamping, however, the signal sent to the two amplifiers passes through a crossover first. That way, the amp feeding the LF driver is only powering the frequencies that will be handled by the bass driver, and the same for the HF driver. Most people that I've read seem to agree that this eliminates distortion issues.

All of the AVR's I've been considering for my own upgrade allow you to utilize the rear surround amplifiers to biamp the front left and right. Part of the setup is to select the crossover frequency to use for the LF and HF feeds. My current front-runner is the Rotel RSX-1562, and this supports this function. I've also looked at the NAD T757, which supports it. I'm planning on auditioning the T777 as well, but the lack of HDMI standby passthrough on the NAD receivers may be a deal breaker for me (I don't want to have to turn on the receiver to use my cable box).

If you're using a 5.1 setup, the T777 will give you biamping that should improve the clarity from your fronts. However, that uses all the available speaker and amplifier connections. I haven't looked at the manual, but if there are additional pre-outs for the fronts you could drive speakers in another zone (but then you'd have the problem of the crossover you set for biamping).

You might want to look at other receivers with a 9.1 setup - such as Integra and Marantz. Or, if you want to go to separates I know Integra has a surround processor with 9 outputs. I haven't auditioned any of the Integra's yet, but I suspect they don't have the musical fidelity of the NAD or Rotel.

Good luck!

 

[PENG]

In biwiring, you are actually attaching two speaker wires to the same terminals on your amp and connecting to the two different posts on the speaker. Since the same signal is going to each terminal on the speaker, most of the information I've seen suggests that the only real improvement from this is that you're effectively increasing the signal strength, and you can probably get the same result from just using a thicker speaker wire.

I know you are only quoting what others are saying but biwiring, if done with speakers designed to allow for it, is more about forcing the lows and highs to travel through separate wires as the cross over network at the speaker end would be separated from each other with the jumpers removed. I don't believe there is audible sonic difference either.

In both passive and active biamping, you're using two different amplifiers to send signals to the LF and HF terminals on the speaker. In passive biamping, you send an identical signal to the LF and HF side. This means that the bass driver is getting the entire frequency signals, and so is the mid/treble driver. From what I've read - and it makes sense - you don't get much improvement from this as you still need to rely on the crossover circuitry in the speaker to filter out the extraneous frequencies.

That is not correct. You forgot about the crossover network, and that in biwirable/biampable speakers, the high pass and low pass are separated in order to force the LF and HF signals to go through their own pair of wires? Again, I also doubt there is any improvements, but we still need to get the facts right.

In active biamping, however, the signal sent to the two amplifiers passes through a crossover first. That way, the amp feeding the LF driver is only powering the frequencies that will be handled by the bass driver, and the same for the HF driver. Most people that I've read seem to agree that this eliminates distortion issues.

You've got the facts right here, except the last part about distortion that seems more of a subjective opinion. I would think that if someone is "crazy" enough to do active biamping, they could most afford to buy amps that they don't have to worry about audible distortion so that won't even be a factor, definitely not the bottleneck anyway.

If you're using a 5.1 setup, the T777 will give you biamping that should improve the clarity from your fronts.

Well, that may offer some real benefits if two separate amps are used, using the 777 only you are still limited by the same power supply so it is better, but not much better than the biwire scheme. Surely it does not hurt to try.

 

[PENG]

Thanks- Working on it.... The NAD T777 has 7 SPEAKER A inputs. My system will have 5. IF I could reassign the 2 unused speaker inputs from, say, R&L SURR-BACK to one of the bi-amped fronts----IF the 777 can be configured I would't need the C740?

Yes, it is better to go this route than to try and use both receivers as Mark pointed out the gains may not be the same so it get complicated trying to make sure they give the same outputs. As far as sonic improvements, probably the best way is to try it and find out for yourself. It is like the topics on whether well designed amps sound the same if not driven beyond their limits, or do expensive DAC sound better, you will always hear arguments from 3 camps (the yes,no,may be/depends).