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Paul T. follow up about NAD A/V, help from Hawk

 

whiteusmc75
Posted on   
Dearest Hawk or anyone willing to help,

I noticed that in a previous post to Paul T. that you had suggested the NAD T742 for his LSi series Polk Audio speakers because of the 4 ohm load. My question is this....Would the minimal output of only 50 wpc from the 742 really be enough to power the higher quality Polks, and get your moneys worth out of them? You have suggested the T762 to me, and I wondered if it would actually do a better job, or if it would even be neccesary to get the extra wpc from the 762 over the 742????
 

Hawk
Posted on   
Forgive me if I didn't explain it fully. I thought you were originally asking for something like 100 wpc, but I may have confused you with someone else. I may have also suggested the 762 because it was in the same price range as something else you were asking about to go with your Polks.

I do try to keep within a person's budget, and make my recommendations based upon budget, speakers, and room size. So help me here and let me know which Polks you want to get and the approximate size of your room.

It is hard to describe, but a watt of power is not equal from manufacturer to manufacturer. The FTC requires the power be rated at 1kHz into an 8 ohm resistive load. Well, I have never come across any speaker that was a pure 8 ohm load. Typically, an 8 ohm speaker's true resistive load will fluctuate from anywhere near 4 ohms to as high as 22.5 ohms, depending upon frequency. Most mass market receivers are designed to meet the FTC requirement, so they sound a little weak when truly driving a speaker. NAD's advantage is that they design a receiver with both a big power supply along with dual power rails, so more power can be delivered when the signal calls for a big increase in power. They are also designed to power the full audio range, not just 1 kHz. The net effect is that an NAD watt is bigger than a watt from a mass market receiver.

So, the 742 will sound cleaner, louder, and more authoritative than other brands 100 wpc receiver. It seems to defy logic, but it is only because the FTC rule is so screwed up. You don't need a 762 to drive the Polks. The NAD 742's power into a 4 ohm load would work out to 100 wpc for two channels. Into five channels, the 742 probably does about 85-90 watts continuous per channel (again into 4 ohms). However, if your room is larger than normal, you may want to step up to the 752 or 762. Furthermore, I do think that the 762 will sound better than a 742, because it as a lot more power. It has a lot more inputs and a better remote, as well.

I am sorry if I confused you. I hope this helps. If not, I'll keep plugging away.
 

Paul T.
Posted on   
That was the next question I was about to ask WhiteUSMD!! I know the NAD T742 is rated at 100wpc with 4 ohm speakers but wondered if I should move up to a higher wpc NAD receiver so not to make it work as hard and I always went by the rule more power the cleaner the sound. My thinking is it would have less of a load powering the drivers. But when it comes to higher end components such as NAD maybe my thinking is wrong.. Also depends on which Polk LSi's I go for, the LSi9's will need a little more power to drive then the LSi7's. So I guess if I go with the LSi7's the NAD T742 will be just right but if I do decide to go with the LSi9's should I move up to a more powerful NAD receiver?? PS Thanks for you help Hawk, sure is nice to have knowledgeable people here to help us get it right the first time :)
 

Hawk
Posted on   
More power is always a good thing (I feel like Tim Allen, here). If you have the money to go for more, do it.
 

G-Man
Posted on   
I agree with Hawk. Of course, different manufacturers measure power differently. Again, a good but not always exact rule of thumb regarding power--the closer to double the 4 ohm resistance reading in watts is to the 8 ohm, the better the amplification. It is usually indicative of having more Ampere's driving the wattage. Now there are a couple of oddball designs where this is not true--but as I said--it is a good general rule.
 

nd4040
Posted on   
How would the NAD stand up against the Denon 4802?
 

TWN
Posted on   
I think I can give say something here, as I am now using NAD T742 and Polk Lsi9 and my room is about 15'x16'.

I am happy with this combination and the NAD really sound better than a lot of mass market receivers (e.g. Sony). Even 742 only rated 50 wpc, it is enough for me (I rarely need to turn up to >-10 for the volume).

Of course, if I had enough money, I would definately go for bigger power model. But at this point, I am more than satisfy with my NAD.

The reasons for me to think that a better model such as 762 (or even 7X3) is that they can give you more power and it is essential for very dynamic sound (e.g. you can test this with the opening of the 3rd movement of Beethoven 5th Symphony). Lack of power may gave you a feeling that some "delay" in the sudden change of volume.

Another point is that 742 is very simple in its features, in a way that it is not very easy to upgrade, say from 5.1 to 6.1 or 7.1.

For me, 742 suits my present need. But if you can afford something better, why not?
 

Hawk
Posted on   
nd4040:

I have the Denon 3803 and all of the NADs kicks its sorry butt, even the comparatively lowly 742. Now, my Denon has a lot of "features" not found on any NAD, but I find I really don't use them very often, if at all. Where the NAD really shines, however, is in the sound quality. All three of the NAD models (soon to be four) have a clarity and power that my big Denon cannot match. I was shocked when I got my Denon set up that it didn't have more power--after all, it is rated at 110 wpc and is a 7.1 channel receiver. Yet, it really strains when I am using it in HT and I cannot get the volume sufficiently high for some real heavy duty DVDs. Then my buddy brings over his 742, rated at 50 wpc x 5 and it has more quality volume and resolution of the sound (we can hear the background conversations on DVDs clearly) than my Denon which costs twice as much. So how does a Denon 4802 stack up? Does it matter when the NAD is less than half the cost and no worse than just as good (and probably better)?
 

Anonymous
Posted on   
Hawk,

Just curious. I have read many of your informative posts over the months and you always crap on your Denon 3803. For the life of me, I don't understand why you didn't return it because it didn't meet your expectations. Hell, for someone that enjoys music as much as I think you do, I would expect a fury and then resolution to your delema. RETURN IT!!!!

It might be too late, eh?
 

Hawk
Posted on   
I bought a refurb and shortly after getting it, I was hospitalized for a period of time. By the time I was in any shape to do anything about it, it was a little late to return it. Everything has a priority and at the time, the Denon was not a big one, if you know what I mean. I probably crap on my Denon because I am finding I am getting more and more dissatisfied with it the longer I have it. Still, it is a good unit--it does everything it is supposed to do. I just don't get any satisfaction from it. Oh well, lesson learned.
 

whiteusmc75
Posted on   
How good of a receiver is the Yamaha RX-Z1?? How about compared to other A/V receivers around the same price range?
 

whiteusmc75
Posted on   
How about the Yamaha RX-V3300?
 

John A.
Posted on   
Hawk and G-Man are completely correct about power. I first read NAD's stuff about their receiver power on paper being worth more in the real world, and was very sceptical. But from my own experience they are completely right: I went down in stated power when I replaced a Sony power amp with an NAD receiver (100 W -> 60 W) but I went up in real volume of sound, not to mention clarity of sound.

Here is the NAD line on power ratings:

http://www.nad.co.uk/power/

whiteusmc75: have look at that link, imagine a Yamaha is "Brand X", and I think you have the picture.

I think the T742 at 50 W will sound better and give greater clean volume of sound than many receivers rated at 100 W+.

About Hawk and his Denon; it takes a long time to get used to a system. What may sound like an instant improvement, even to a discerning listener, may get tiring and disappointing over time. In years gone by you had that problem, in spades, with turntables. Now we have digital sources there is probably less variability at the source end.

One good thing about places like this is we can learn from each other's mistakes.
 

dmeister
Posted on   
Actually, the FTC doesn't require manufacturers to specify power ratings at any load, frequency, or level of distortion, which is part of the problem that companies like NAD face. The FTC only requires that manufacturers specify *how* the power was rated. Many like to play the "numbers" game. You should look for:

1. Frequency. Is the rating across the full range, as it should be (i.e., 20 Hz to 20 kHz), or simply at one frequency (i.e., 1 kHz)? Remember, speaker impedance drops as the frequency drops, which means that the receiver must deliver more current for bass response. Consequently, a receiver rated for 100 Watts at 1 kHz won't necessarily provide that much power at lower frequencies.

2. Channels. Is the rating with *all* channels driven simultaneously, as it should be, or simply with one channel driven? A company that claims "5 x 100 watts per channel" for its receiver doesn't necessarily mean that the receiver can deliver 100 WPC in all five channels at once. Obviously, five channels running will suck up a lot more current and capacitance than just one or two channels.

3. Impedance. Most ratings will be for an 8-Ohm load, since this is probably the most common nominal speaker impedance. Be sure the impedance values match when comparing receivers. Some manufacturers will also provide ratings for a 6-Ohm load, which is more of a European standard. Compare the ratings for both 8- and 6-Ohm loads if they are available (and even 4-Ohm), though. Ideally, the power rating of an amplifier should increase as the impedance drops. A *perfect* amplifier, for instance, will provide twice as much power for a 4-Ohm load as it does for an 8-Ohm load. A good *high-current* receiver will have a higher power rating for 4- or 6-Ohm loads than for 8-Ohm loads.

4. Distortion. Is the rating for a relatively low level of total harmonic distortion (THD)? The lower the level of THD, the more stringent and conservative the manufacturer was with the power rating. While the difference between 0.05% and 0.5% THD may be inaudible at normal levels, a receiver rated at 0.05% will definitely strain less during dynamic passages, be less likely to clip, and will deliver cleaner power at higher volumes than the receiver rated at 0.5%.

5. RMS vs Peak. This probably isn't an issue anymore, but power ratings should be given for RMS (average continuous) power, not peak power.

Consequently, a company like Sony or JVC may give a rating of 100 WPC for one of its receivers, while a company like Rotel or NAD may give a rating of 90 WPC. You may think you're getting more power when, in reality, you may possibly be getting considerably less power. So it's important to check the fine print. ;-)

Anyway, sorry for the digression.
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