Hawk, T742 4ohm??
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Paul T | Hawk you scared the bejesus out of me with a post in my "Buying NAD Online" post earlier... You stated you didn't think the T742 can power a 4 ohm speaker for is doesn't mention it in the manual.. I was all set to order one to drive a set Polk LSi 7's I am ordering.. The T742 seems like the perfect amp for these speakers being they are small and wouldn't need a big powerful amp to drive them, but it had to be a receiver capable of driving 4ohm speakers... I went to the NAD site and it did not mention 4 ohms in the owners manual for the T742 but at http://www.nadelectronics.com/support/productinfo_framset.htm the data sheet reads for the T742 2 x 90W (19.2dBW) 2 x 130W (21.1dBW) 2 x 175W (Min. power per channel, 20Hz - 20kHz with no more than 0.08% THD rated distortion) IHF dynamic power; 8 ohms IHF dynamic power; 4 ohms IHF dynamic power; 2 ohms Does this mean it is built to drive 4 ohm speakers??? I need to know before ordering.. Thank You for your help!! |
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Hawk | Paul T: Sorry to have scared you, but I was talking about the Magnepans, which have a much lower impedence than the Polk LSi series. We had a post on this forum about two months ago from the owner of Polk LSis who wanted to know if either Onkyo or NAD would drive his speakers. Somewhere, I know I found the impedence curve of his LSis, but I couldn't be sure. Anyways, he contacted Polk Technical Support group and they specifically mentioned four brands they recommended to drive the LSis: NAD, Adcom, B&K, and Rotel. So, I think you are safe to get the 742. BTW, I know we have been around the world on this 4 ohm thing, but it is really hard to say one way or another because what is a 4 ohm rating from one speaker manufacturer is a 6 or 8 ohm rating from another manufacturer--there really is no good rule of thumb here. Furthermore, some 4 ohm loads are harder on receivers than other 4 ohm loads (it gets far too technical to explain it all here). Thus, it makes sense to contact the speaker manufacturer's technical support department for advice on this issue. They will know best. Paul, again, I apologize for scaring you on this issue, but I am sure the 742 and the Polks will work very well together. Please give us a full report once you get it up and running. I value your impressions as much as you value mine. Thanks for asking. Have fun. |
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| Paul, Like Hawk says I would recommend contacting NAD tech support regarding the issue. However, it does mention in the NAD T742 manual that the receiver is designed for 8ohm minimum speakers. I don't have the manual handy but I believe it's in the speaker connection section early in the manual. BTW, I picked up a T742 last Wednesday am extremely happy with it. |
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John A. | Paul T., I think you are completely safe with that combination. My receiver is an earlier NAD with the similar output and the words in the user manual are: "This unit is designed to produce optimum sound quality when speakers with impedance within the set's ranges are connected. Please check the following information and choose speakers with the correct impedance for the connections. FRONT SPEAKERS: 4 ohms min. per speaker CENTER SPEAKER: 4 ohms min. SURROUND SPEAKERS: 4 ohms min. per speaker" If you wish to triple-check, you can download the T742 user manual as a pdf file from the NAD web site. But if Polk LSi 7 speakers won't work with the T742, what other receiver options do you have? Many other receivers say never use speakers of less than 8 Ohms. I doubt if Polk would make something that far out of line, there would hardly be a market for them. |
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Boots | Smitty, I too am looking at getting a T742. How do you like yours? Did you order it online and does it have the upgraded firmware? I can't get it locally so will have to order it from DMC and I'm hesitant as if there are any problems with it, I'll have to ship it as opposed to just returning it to a local dealer. What kind of speakers are you running? Thanks and good luck with the 742! Boots |
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GT | I was browsing over at the Club Polk section on Polkaudio.com and most people say you need separates to drive the Lsi speakers. Others are using high end AV/Receivers such at the Rotel 1055. Most likely the NAD 752/762 would also work. I think it would be wise to call NAD and/or Polk for some advice. Apparently these are very difficult speakers to drive. |
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| John A., the T742 manual is different. Here is the section of the T742 user manual I was thinking of:
Boots, have a look at this thread for my impressions of the T742: T742 review I'm not sure how to determine the T742 firmware version, I've asked NAD tech support about it but they haven't gotten back to me yet. I certainly haven't experienced any of the problems detailed in other threads with the T752/T762. |
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John A. | Smitty, Thanks. OK. Paul T., the spec has changed, or at least, the manual. My guess was incorrect! That is strange. My model is the older T760. I wonder how the T752 and T762 shape up. Your T742 review is great, Smitty. |
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| John A., The T752 and T762 are 4ohm capable as per the following note:
Thanks for the compliments on my review. BTW, I watched Chicago on the weekend in DTS, and as the wife said it was 'brilliant!'. I'm simply amazed at how great the sound is, it's just stunning. I watched part of the tribute to Willy Nelson's 70th birthday and it was amazing. |
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John A. | Smitty, Thanks. So the 8 Ohm recommendation must apply to the T742 alone. Personally, I would audition it, and check with both Polk and NAD. These impedence figures are only best guesses. But, strictly, Hawk was right, yet again. I think I will buy a copy of Chicago. My wife loved that movie. Very reminiscent of Cabaret. I believe that has been digitally cleaned up for DVD, but does not have the same sound. The thread What's the best DVD to test out my new system? had a nice post from G-Man about Chicago. |
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Boots | Smitty, Great review on the T742! So, from what you are saying, despite that the manual says only 8 ohms speakers(and I saw it too in the manual I downloaded from the NAD website)it works fine with your 4 ohm speakers? That's great! Also happy to hear you have not found any of the bugs so many folks have reported here, i.e. clicking when changing volume, CDs skipping on the first few seconds of a track, "thumping" when turning the unit off or changing DSP modes. I take heart in your review as I was starting to get wary of the T742, and really was closing in on it as my receiver of choice. (I will probably go with either PSB Image 4Ts, or DefTech BP6 for the fronts) BTW, here's a link that shows how to check the firmware (at least on the T752) {http://www.massey.ac.nz/~jcmarsha/hometheatre/} Best of luck! Boots |
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Hawk | Paul: I posed your question to NAD and got the following response: "Thank you for your recent request via the NAD Electronics web-site. I spoke with technical services regarding your questions, and here is their input: The T742 can handle 6 to 8 ohm speakers only. Best regards, Karen Pritchard" However, I again suggest that you contact Polk about the speakers because you need to understand whether their 4 ohm rating (for the LSis) is a nominal or minimum rating. If it is a minimum rating, its nominal rating may be something much more like 6 or 8 ohms, in which case the vast majority of receivers can handle this type of load. Regards. |
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| Boots, Thanks for the compliments on my review, I enjoyed writing it. However, I do not have 4ohm speakers, my speakers are all 8ohm. I haven't noticed any of the reported bugs. When switching DSP modes there is a 2-3 second delay [certainly there are no loud popping noises] during which time the sound is muted. I haven't and have no plans to set the volume to +18 (max) with no source and switch DSP modes. Now, maybe there is some good 'audiophile' reason to do this as a measure of the quality of the receiver's components and maybe I'm being naiive but to me this makes about as much sense as switching off the main electrical circut to my house, turning all the electrical appliances on, and then flipping the main circuit back on to see if something goes wrong. I don't notice any background noise when listening to music, including some classical music with nearly silent passages at +0db, this is a more important 'measure' to me. Regarding the sound delay, I don't really see what the big deal about this is, generally I'm either listening to a CD in stereo/enhanced stereo or I'm watching a TV show in DPL II Movie mode. Sometimes I'll switch the DSP mode from DPL II Movie to enhanced stereo if I'm watching a music video and have to wait the 2-3 seconds. No delay would obviously be better but it's hardly something that would influence my decision on which receiver to purchase. Different things bother different people, personally it bothers me more when I'm watching a DVD and 'CD' is displayed on the receiver display(because I've hooked my CD/DVD player to the CD digital coax input on the receiver) but that's just me. It doesn't bug me enough to shell out $30 on a digital optical cable so I can hook it up to the receiver's DVD input though  . There are certainly some drawbacks to the T742 such as the lack of digital outputs, lack of front panel digital inputs, no S-Video input on the front, fixed 80Hz crossover, relatively low number of input sources, no bass management on 5.1 direct inputs, no 6.1 decoding or main-amp inputs, digital inputs are not re-assignable, it does not claim to support 4ohm loads and no component video switching. But the sound is awesome and the price is reasonable. Regards, Smitty |
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Paul T | Hawk, Thank You soo much for taking the time to look into the 4ohm question with NAD... I was afraid of that, I did e-mail Polk's Tech support yesterday and asked about the T742 and the LSi series and they replied today stating the T742 would not be a good choice.. They stressed it should be a amp or receiver built to handle 4ohm speakers.. so I guess it's either the Outlaw 1050 or the NAD T752 in which case the $499 Outlaw will probably win out over the $699 NAD... Thank You again Hawk you are soo helpful here on the Ecoustic forum!!! |
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Boots | Smitty, Sorry about that...I got you confused with PaulT who started this thread. He's got the 4 ohm speakers. Thanks for the thoughts on the alleged bugs. Happy to hear of your satisfaction with the 742. I'll be ordering mine today. BTW, did that link I posted above do any good in identifying the firmware version? Regards Boots |
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| Boots, I didn't mean to 'shout', I just wanted to make sure you were aware that I wasn't running the T742 with 4ohm speakers . Thanks for the link, but the T742 doesn't have the same front panel buttons that the T752 does, including the ones used to display the firmware version. However, I did receive a reply from NAD regarding the T742 firmware and essentially it's a different firmware that the T752/T762 uses and has not had any revisions to it...very good news! Oh, one other thing, if you plug the T742 into a power bar, make sure it's a high quality one, I had temporarily plugged mine into a cheapo powerbar and noticed some background noise on loud volumes, this went away when I stopped using that power bar. It seems to be a lot more sensitive than my previous HK in this regard. Hope you enjoy your new T742! |
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Boots | Hey Smitty, No problem. Sorry the link wasn't helpful. I'm looking to get the 742 with PSB Image 4T, but have had a hard time finding a place that stocked both so I could listen to them (hate buying totally blind) I found a place in NJ (about 2 1/2 hours away) so I am planning a trip on Thanksgiving weekend to hear them and hopefully purchase both. I'll let you know Boots |
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