Bi-amping using my NAD T773...awesome!!

pearsall001

As many of you know, I recently sold off some of my gear. One item in particular was the Van Alstine OmegaStar 440EX amp (220x2). I was concerned that my AAD 2001 monitors (86db sensitivity/8ohm) would suffer the consequence. Man oh man was I ever wrong. As good as the AVA amp was both musically & power wise, my NAD T773 came thru without skipping a beat. Being a 7.1 avr & only running a 5.1 system I decided to see if I could bi-amp using the spare amp. I emailed NAD & they told me how to do it, very simple to say the least. WOW!!! not only am I impressed with the sweet, laid back sound of the NAD, the power is just awesome. Truth be told I don't miss the AVA amp at all. That's not putting down the AVA at all, I'm really giving kudos to NAD for a tremendous product that I had sitting there all the time.

I read a lot here about the necessity of a 2 channel amp to really make your speakers sing. I guess it all depends on the quality of the AVR you have & if you can bi-amp with it. I would highly recommend going the bi-amping route first before investing in a separate amp. Just a thought.

Yashu

I have owned my NAD integrated for longer than any of my other parts, I have thought about a lot of different amps, but when push comes to shove, I cannot find a GOOD reason for me to switch without having to spend ALOT more money.

The power is truly amazing really... rated at only 60 watts, this thing feels like an amp of several times that power. NAD has done a pretty damn good job at giving you quality without wasting needless money and space on pointless features. The sound is something that I cannot find much fault with. I have listened to many other amps, and again, I come back to the NAD with renewed appreciation. The sound is full, but not too forward, laid back... like you said, but not without dynamics or detail. NAD has a "house" sound that people either love or hate.

I will probably upgrade to a seperate pre eventually (the fact that everything is moduler in a NAD integrated/receiver is great in itself), but the NAD poweramp section is good enough that I don't see needing to replace it any time soon.

That is really cool that you are using the extra channels in your reciever to bi-amp... I never thought about that, but what a great way to double the power for your mains when you have a multichannel reciever. I am glad to see another NAD fan... I feel like their prices puts them "below the radar" of alot of audiophiles.

JimBRICK

Nad Rules

hearingimpared

I need to get my ears on this Phil, I have a T773.

heiney9

Yashu wrote: »

That is really cool that you are using the extra channels in your reciever to bi-amp... I never thought about that, but what a great way to double the power for your mains when you have a multichannel reciever. I am glad to see another NAD fan... I feel like their prices puts them "below the radar" of alot of audiophiles.

Glad this has worked out. Just remember you are not really doubling the power. The extra channels still use the same power supply to draw it's power from and in some instances (not this one) bi-amping with extra channels results in no improvement.

H9

madmax

pearsall001 wrote: »

I read a lot here about the necessity of a 2 channel amp to really make your speakers sing. I guess it all depends on the quality of the AVR you have & if you can bi-amp with it.

Its certainly more about quality of parts and design than packaging decisions.

BTW, what TT/cart are you using for the source?

madmax

pearsall001

Yo madmax,

It's a toss up between the Clearaudio Statement TT & the Gemini TT. Damn, tough decision here. Little help please!!!!

Phil

pearsall001

hearingimpared wrote: »

I need to get my ears on this Phil, I have a T773.

Joe, you're gonna be listening in utter amazement. It sounds like you're sitting at the "Jazz at the Pawnshop" Nice I tell ya!!! Nice!! This NAD bi-amped is nothing short of amazing.

How do you like my new signature?

dkg999

But it's not 200 wpc, how can this be

heiney9

dkg999 wrote: »

But it's not 200 wpc, how can this be

Oh man when Cathy see's this she's going to be all over you dkg999. I'll be checking back often .

dkg999

The lines about 10 deep to kick my ****, she'll have to take a number :eek:

heiney9

dkg999 wrote: »

The lines about 10 deep to kick my ****, she'll have to take a number :eek:

I have a special "move to the front of the line" pass I could give to her :eek: <jk>. Ladies first!

dkg999

You could make a lot of money right now with that pass!

pearsall001

dkg999 wrote: »

But it's not 200 wpc, how can this be

How does that work? How do I know what's being delivered between the 2 amps? The manual states: 7x110 in surround mode all channels driven, 2x145 into 8ohms,two channels driven. If I'm bi-amping do I multiply the 145 figure? That seems kind of high doesn't it. Anyway NAD is very conservative with their ratings. All I know is it gets the job done without breaking a sweat. I'll email NAD & get their take on this question. I'm more curious now.

dkg999

Ummmm, I think you missed the joke and sarcasm in my post!

WilliamM2

How does that work? How do I know what's being delivered between the 2 amps?

For one, you would have to know the resistance of each circuit in the crossover. The other thing to consider, is that even if the woofer section is drawing 100 watts, the tweeter section will probably only draw 5 to 10 watts to play at the same level. So even if you bi-amp, you are not doubling the power, or anywhere close.

pearsall001

dkg999 wrote: »

Ummmm, I think you missed the joke and sarcasm in my post!

Not at all, you hit the nail right on the head I know Cathy is phanatical about running at least 200 watts or go home!! I'm anxious for her response on this one. Who knows, maybe with bi-amping maybe I'm pushing more than 200? Anyone know how to figure this out?

John K.

Pearsall, no figuring is necessary; the same power supply section in your T773 is simply feeding its same amount of power through two sets of output transistors rather than one. The output transistors are simply valves which measure out the required amounts of power from the power supply section at given instants, but they have no power of their own to add. The available power to each section of your speakers remains the same as before; it isn't doubled and can't be increased by any amount. Your T773 was, and still is excellent.

Yashu

You are missing the point. You are assuming that the PSU is the only limit here, and that is just not true. Those transistors are most of that limit... the NAD specs prove this point very clearly: "7x110 in surround mode all channels driven, 2x145 into 8ohms, two channels driven."

This spec here clearly means that each channel stage transitors' limit is about 145 watts continuous, and that the PSU is strong enough to drive 7 of them at 110 watts. The OP was already driving 5 channels, so using the extra 2 would nearly be doubling the max *available* power to the set of speakers he is wanting to bi-amp. The fact that the HF sections of the speakers use less power just means that, on top of gaining the use of those dormant transistors, he is better distributing the load of his speakers.

Furthermore, with respect to NAD power supplies, all current NAD amps feature PE circuits, so there is reserve power for many times the rated wattage for short bursts of up to about a second or two, which is the reason NAD amps always sound more dynamic than their ratings suggest.

NAD designed this amp with driving all 7 channels in mind, why shouldn't it sound best this way?

heiney9

Believe what you want your explanation is pretty far off. Pearsal, glad you are digging it. Nothing wrong with NAD gear, enjoy. Isn't this hobby fun!

H9

dorokusai

John K. wrote: »

Pearsall, no figuring is necessary; the same power supply section in your T773 is simply feeding its same amount of power through two sets of output transistors rather than one. The output transistors are simply valves which measure out the required amounts of power from the power supply section at given instants, but they have no power of their own to add. The available power to each section of your speakers remains the same as before; it isn't doubled and can't be increased by any amount. Your T773 was, and still is excellent.

I agree, you're simply getting what you had in the first place. It's more of a perceived change. If you hear a difference, then it exists, period. The amplifier was the same then as it was now, so it has little to do with actual power, because nothing really changed internally. That's why I love loudspeakers. They usually voice the changes, not the gear. We can speculate about load, source impedance mismatch and this or that but that's for a magazine.

I love the NAD PE and the cousin, Onkyo WRAT, in regards to amplifier design. Enjoy your gear, don't sweat the small stuff.

Yashu

But there IS a change, a real one... he is using 2 extra channel's worth of power transistors that were lying dormant before... and not only that, but he is now using a total of 4 channel's worth of power transistors for his mains instead of two. Two channels can deliver a total of 145WPC (since he was using 5, this value would have been lower), this is the max load for the transistors at 8ohms, but even if you use the rating at 7 channels continuous, he has access to 220 wpc now FOR HIS MAINS... The difference is enough to hear,the capability is there and the loads are more evenly distributed within the amp.

There is no reason to just let extra channels sit idle if you can do this... There is more to an amp than just a power supply... Why do you think that with two channel driven the amp can only deliver 145wpc (making it 290w total) but 110wpc over 7 channels (770w total)? He is hearing a difference because there IS one.

heiney9

Yashu wrote: »

But there IS a change, a real one... he is using 2 extra channel's worth of power transistors that were lying dormant before... and not only that, but he is now using a total of 4 channel's worth of power transistors for his mains instead of two. Two channels can deliver a total of 145WPC (since he was using 5, this value would have been lower), this is the max load for the transistors at 8ohms, but even if you use the rating at 7 channels continuous, he has access to 220 wpc now FOR HIS MAINS... The difference is enough to hear,the capability is there and the loads are more evenly distributed within the amp.

There is no reason to just let extra channels sit idle if you can do this... There is more to an amp than just a power supply... Why do you think that with two channel driven the amp can only deliver 145wpc (making it 290w total) but 110wpc over 7 channels (770w total)? He is hearing a difference because there IS one.

That's not at all how it works. Get your Google on and learn about amplification, outputs, multi-channel, power supplys, rail voltage, etc and then you'll understand. This no small subject so expect to spend a few weeks or more to grasp the proper concepts. It's not as simple as summing the manufacturer's specs. As a matter of fact that has nothing to do with it whatsoever.

Not trying to turn this thread ugly. I think it's great that Phil (Pearsal) is enjoying his receiver and it's new role in his rig, that's really all that matters.

H9

hearingimpared

pearsall001 wrote: »

Joe, you're gonna be listening in utter amazement. It sounds like you're sitting at the "Jazz at the Pawnshop" Nice I tell ya!!! Nice!! This NAD bi-amped is nothing short of amazing.

How do you like my new signature?

I can't wait to hear it. . . Nothing like trimming the fat.

hearingimpared

heiney9 wrote: »

I think it's great that Phil (Pearsal) is enjoying his receiver and it's new role in his rig, that's really all that matters.

H9

This where I totally agree when these kind of debates go on. Phil hears something wonderful. . . He states it clearly, it doesn't matter whether it's amplification, front end, cables, wires or room treatments, he clearly hears and enjoys the difference because he has done so with his 773 now I want to try it with mine. I would have never thought to do so had Phil not tried.:)

marker

heiney9 wrote: »

The extra channels still use the same power supply to draw it's power from ...

FWIW, the T773 has not just one, but two toroidal transformers, one for the front three channels, and a second for the other four.

madmax

Yashu wrote: »

Those transistors are most of that limit... the NAD specs prove this point very clearly: "7x110 in surround mode all channels driven, 2x145 into 8ohms, two channels driven."

This spec here clearly means that each channel stage transitors' limit is about 145 watts continuous, and that the PSU is strong enough to drive 7 of them at 110 watts.

Totally agree here. Couldn't read the rest of it as I was falling asleep.

madmax

cfrizz

Enjoy Phil.:) H9 I do like a man who knows how to be a gentleman!:D

As for the rest of you...:p

WilliamM2

Everyone seems to ignore that the tweeter will only draw a few watts. I've done the experiment myself with my CSi40, I am currently bi-amping it with 2 channels of a 150wpc amp. It has no more output, or at least not enough to register on the SPL meter, than it did with one channel at 150wpc. Oddly enough, it still seems to sound the same as well.

Yashu

It depends from amp to amp... plus, there is a very good chance that if your amp was already of high enough quality, it was already able to deliver the power your speakers needed for their best performance.

NAD is very honest with their specs, as testing has consistently shown in measurements done by Stereophile and other magazines... They even measured their PE circuits and soft clipping... all pretty interesting actually. It is one of the reasons I respect NAD so much.

Anyway, I understand enough to know that there is more to an amp than a PSU... I never claimed to be an electrical engineer, I have only done some light electronics work and modding, but I don't think I am going to be convinced that output transistors have limitless power handling and that the only thing that matters is the power supply... sorry h9.

Don't get me wrong, there are plenty of cheap receivers out there with grossly overstated specs with puny PSUs, but NAD is not one of those brands.

I would have thought one would argue that an extra 75wpc would not yeald very much in terms of actual possible DB level before trying to argue about transistors and PSUs, that is what people usually argue about when it comes to this kind of thing.

I think that even if it would give you only a few extra max DBs, that max DB level doen't matter that much anyway, and that it is dynamics, power though transients, and a more evenly distributed load within the amp itself that would make this kind of project worth it.

I have OCD, and so even the fact that there are now no more dormant channels would make it worth it... to me anyway... since 7 channels were paid for, 7 should be used.

VR3

Technically you arnt biamping, you are just powering to like signals into two jacks.

True biamping would have an amp crossed over to only runs the highs, and the other amp cut off from powering the highs -- so its doing all it can for each individual piece.

But anyway, cool deal.