Nad M25 / Parasound A51 / LSiM Series / HT Use 80%

RocketOCannon

Considering buying one of these two amps. I think I really want the Parasound...great amp..gobbs of power.
These will be used in a 5.1 HT set. powering LSiM 707s, 703s, 706c and Micropro 4000.

My concern is underpowering the speakers and also...maximizing the speakers potential between these 2 choices.

Here is what someone discussed with me regarding the two. I would like some feedback with you folks who know more then i do about the technical side of this.

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Hi Rick,
I did some research on the products you planned on using and did a little math based on the specs given on their respective websites. Without even getting into games played with wattage numbers (for example, I can't help but notice the THD number(0.2%)used on the Halo A51 rating is above what NAD considers clipping) we can look at the basic numbers to see what the difference would really get us. If all other things are equal, and we compare the Halo A51 versus the NAD M25 with the speakers mentioned, here's what we need to look at:

The Polk LSiM 707 is rated to 88 dB/W/meter
Doubling power gains us 3 dB (the smallest increment of volume the average person can reliably detect).
So the raw numbers provided the differences in stated power are:
Halo output - 111.98 dB
NAD output - 110.04 dB

So I guess the real question is: why 250 WPC? The difference between the NAD's and the Halo's output will be minimal, practically undetectable. The room isn't terribly huge and you probably won't be playing your system at reference levels most of the time. I know you were worryied about damaging the speakers from underpowering them which is a valid point if you were talking about using a Yamaha or something like that where distortion is a huge issue at high volumes. Distortion is what will damage the speakers and NAD will play at practically the same volume levels as the Halo with a lot less distortion. Also, NAD comes with a smaller price tag.

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Thoughts?
Advice?
Opinions?

Reviews for both seem excellent. Just want to make sure I choose what I need...or continue looking at some other options. Pre amp is still TBD.

Thanks,

pearsall001

Tough call, they are both beasts to be reckoned with but the NAD is a 7 channel amp which will give you room to grow down the road if you go to 7.1. The A51 is a 5 channel amp. Both will do the job in spades & will power any other speakers you might have down the road. I would go with the M25 & pocket the savings.

newrival

I'd recommend looking into other brands as well: bel canto, wyred 4 sound, etc.

Kex

It seems to me that you have gotten some pretty sound advice already.

I don't know those particular amplifiers, but I can tell you that I drive speakers rated 3-6 ohms, and only 83dB efficient (so far more difficult to drive than yours). I use a NAD receiver rated 90w/ch x 2, or 70w/ch x 6 without any external amplification at the moment. I listen at reference levels quite frequently and have never had the slightest hint of clipping. In fact, I don't even use the soft clipping feature built in to NAD components. During testing and calibration well beyond reference levels, I was never able to get the soft clipping warning light to ignite, or detect signs of clipping, so I turned soft clipping off since I knew I would never listen at such loud levels anyway.

I would be confident that the M25 is even more conservatively rated, with a better power supply. Note, however, that I believe it uses several small PC type fans for cooling on it's underside. That's not necessarily an issue ... in fact, it might be a good thing for a multi-channel amp in particular, but it might bother some people. My receiver has the same type of fans (four of them) and they have never bothered me in the slightest, but this may depend on where the amplifier will be located. I'm guessing that it won't be beside your listening position, but just in case, I thought I'd mention it. The noise, when everything else is completely silent, is comparable to a quiet laptop in my estimation.

All of that considered, however, if you think you would prefer the other, for whatever reason, why not just get it? After all, there is no wrong decision to be made here. Both will work they way they are intended to work.

RocketOCannon

All,

Thanks for the insight.
If anyone else out there has thoughts or insight please chirp in. :>)

I know they are both nice amps. Me being not up to speed with all this, I was more concerned with the neanderthal thinking of wpc. I wanted to get an amp that would get me in the ball park of the rated 300wpc of the 707s, still provide clean power and try not to sell the dog and the wife to accomplish it.

Sounds like the NAD is just flat out more efficient even though I probably can't go wrong with either one. The truth is, I won't be listening at reference levels and if I do it will most likely be for "Show-off" time anyway...

Is there any specific amps in this ball park that I should do some homework on? ...it would be very helpful if someone noted amps "A, B, C" to check out. I will look around the co's listed above as well.

Thanks, I appreciate the info. It really helps me make sense of the homework I have already done.

tonyb

Change your mindset, get off the watts thinking, especially the recommended watts for speakers. Current is whats needed, not high wattage. Most any SS amp in the 150 watt range and up will have enough current to drive those speakers to their full potential.

Other amps ? New or used ? Budget ? Don't forget cables, leave some coin for some good cables.

ambiophonics

Just for the record, I believe 1dB is the smallest increment of volume the average person can reliably detect. A 3dB increase would require twice the amount of power.

The Polk LSiM 707 is rated to 88 dB/W/meter
Doubling power gains us 3 dB (the smallest increment of volume the average person can reliably detect).
So the raw numbers provided the differences in stated power are:
Halo output - 111.98 dB
NAD output - 110.04 dB

RocketOCannon

My thinking has changed. the numbers make sense. I will keep snooping around but this advice has allowed me to zero in towards a few units to make a final decision on based on the details.

I think Im willing to spend just north of 3g on amp...looking at used, unless a dealer wants to make it happen for "new" a little above cost. I have actually had some luck with this approach. Regardless of where and how I make my purchase..it will be determined by the situation at hand and funds available at the time I decide to buy. I know some folks on here will disagree with this approach... but...I will live, learn and take my lumps if need be.

My thinking is the money saved on used for my overall system will pay or help pay for any problem that might come up where i need to send a unit in for work. If it happens..it happens...I'm willing to take the risk where the product will not be backed by a warranty. Although perfect world I would love to have a warranty for everything I buy...just can't get to the system I want by doing that ($)

tonyb

This is all you need,
....and will make those speakers sing. Musical, a tad on the warmer side for those LSI's, and balls to blow out a window or 2.
http://app.audiogon.com/listings/b-k-reference-200-7-200w-x-7-8-ohm-375-w-x-7-4

RocketOCannon

Kex...interesting insight. Thanks!

RocketOCannon

tony,

Thanks, that is one of the ones I will be looking at when it comes time to purchase. It's always been on m shortlist. Not quite there ($) yet.
What are your thoughts of that amp vs the NAD for my system?

pearsall001

I had my heart set on picking up a used NAD M25...but a killer deal on a Rotel RMB-1095 5 channel amp feel into my lap, I just couldn't pass it up. The amp is a killer & I'm quite happy with it & of course the $$$$$ savings that also came with it. To be honest there's no need to spend 3K large to get a great amp...just my thoughts.

RocketOCannon

Pear,

I agree. If I was ready to pull the trigger I probably would grab the B&K Ref 200 on Audiogon right now. Gonna have to wait a bit still due to wifey having the lockbox on the funds for a little while longer. Once I get the green light. I will look for one of these amps and look for the best deal.

However, this NAD looks to be real nice...smooth...Love the THD #.

Any thoughts or insight to the Marantz pre AV7005? ...or another pre that I might consider for my planned system?

Kex

My initial reaction would be to agree with pearsall001: I don't think it's necessary to spend $3,000 to get enough amplification for the new LSi series: they seem significantly easier to drive than the previous models. But everyone's priorities, and "pain" threshold for spending, are different (not to mention opinions on amplification in general!).

Along the same line of thought, and given my experience with different NAD components, at this point I'm thinking my next HT setup will be driven by one of their upgradeable receivers, featuring dual torroidal power supplies (the T775 and 785). Newer models are being released, so there may be one last big sale on these some time this year. For music listening, I'm thinking about a two channel C275BEE. The power ratings for this seem very similar to the M25, but with only two channels (and no need for fans since there's probably enough room to dissipate heat with natural air flow). Refurbished units are sold by the highly reputable Spearit Sound for $1,000, with warranty, and with free shipping. It's $300 more new from the same outlet:

http://www.spearitsound.com/product.cgi?group=735&product=4313

I don't know if you came across this review of the M25 (along with other components), but it seems to confirm the conservative ratings of the M25 (which has been true of any review of NAD components I have ever read):

http://www.hometheater.com/content/nad-masters-series-m15-prepro-m25-amplifier-and-m55-universal-disc-player-ht-labs-measures

You'll probably notice how the measurements show the amplifier reaching 0.1% THD at over 190W/ch, with all channels driven, whereas NAD rate the amplifier at 160W/ch (at a lower level of THD). The voltage gain is also measured at exactly what the NAD specifications claim it to be, but again, that's nothing particularly new or surprising.

The review also confirms that fans are used for cooling, but the speed of rotation is adjusted according to the sound level of what is being played.

There are differences when you compare the specifications from the Master series to standard NAD products, such as a 20lb increase in weight when comparing the seven channel T975 to the seven channel M25 - probably mostly because of a bigger power supply, but some of it might also be due to other materials used in the construction. I'm just wondering how much of a difference in sound you will actual hear, when push comes to shove.

Once again though, some people would love to be agonizing over such a choice. I don't see how you can go wrong. The only other thing you could do would be to find an opportunity to listen to the equipment for yourself, but that's not always practical, and I don't like wasting the time of a retail outlet when ultimately I'm intending to buy from another source.

RocketOCannon

Kex,
Interesting chart. Great graphic. I agree that if I plan on $$1,500or north of that will get me a sweet amp.
I have been reading many different reviews...did not see that one. Im not concerned with the fans...no biggie.

I am certainly leaning towards the NAD as well since it is 7ch vs 5. I will be adding the FX LSiM surrounds at some point down the road.

I have a pretty good idea of what I want in my power amp...now need to start the journey on learning about the per's.

I have learned a ton from everyone on the CP site that has helped me...Tony, Mantis etc...and a ton others. I appreciate it.

Let me know if you have any thoughts on pre's as well.

tonyb

All the amps your looking at should be great, but seriously, the THD #'s are pretty much negligent, you wouldn't hear that difference anyway. Oh, don't get too razzed up by reviews my friend, it is the internet after all and you can probably find a good review on a **** too. Pay more attention to the sound signatures of the amps and make sure they compliment your speakers. In other words, don't buy a bright sounding amp and pair it with bright/forward sounding speakers. See what I mean ?

RocketOCannon

For sure Tony...I'm learning fast...but so much further to go! lol I also try and read reviews as critically as I can...i know there some horse crap out there with the politics of business etc...but they give me a feel for the product I'm looking in to. My ears will tell me the bottom line.

I will also be doing my due dill on trying to listen to the amps prior to buying.
I've asked this question a few times...does anyone have any opinions on the Marantz AV7005? ....again..lol..good reviews...lots of features and I can get a pretty good deal new. I know nothing about pre's. I am reading about them and learning more but could use some insight here.

RocketOCannon

For sure Tony...I'm learning fast...but so much further to go! lol I also try and read reviews as critically as I can...i know there some horse crap out there with the politics of business etc...but they give me a feel for the product I'm looking in to. My ears will tell me the bottom line.

I will also be doing my due dill on trying to listen to the amps prior to buying.
I've asked this question a few times...does anyone have any opinions on the Marantz AV7005? ....again..lol..good reviews...lots of features and I can get a pretty good deal new. I know nothing about pre's. I am reading about them and learning more but could use some insight here.

iskandam

At one of my local craigslist finds, the seller has a Marantz AV7005 hooked up to the Parasound Halo A51 to power a set of older KEF's. It's a small duplex, so totally overkill for that space, but the sound is amazing. I don't know how much more you'd have to spend to get a significant jump in sound quality from that set up.

RocketOCannon

Im to Giddy not to post.... I scored a NAD M25 - excellent cond on eBay yesterday for $1,500! Be here early next week but can't hook it up since I still have pre amp, speakers etc to buy (LSiM).

But I am "P-U-M-P-E-D"! Like a little kid...I will probably just sit and stare at it...lol

My system is starting to take shape and the basement / HT construction is scheduled for end of May.

Sorry to bore anyone...just pumped to get that amp at a great price! No one else bid.

AHOY!!!

leroyjr1

Nice score!

EndersShadow

Pics or it didnt happen

RocketOCannon

lol

I only have the 707s currently and the NAD will be here next week...kinda boring pics...lol...but as soon as I get all my gear I will def take some pics. I will take pics as the basement takes shape as well. still working out details of equipment placement/closet etc.

I will be buying the 703 rears, 706C and MicroPro 4000 fairly soon. Im also going to stretch some $ and get 2 more 703's for 2 channel listening. And yes for those thinking it...i am going broke and the wife is disgruntled,...but, I don't care! lol Honey Badger don't give a $h-t!! lol

Fyi - I could have gotten the M25 new w warranty for $2,600...but the spread was to big...went with the used.

PrazVT

Congrats!! I too am a proud owner of this 96lb beast :cheesygrin:

The M25 has plenty of power and I suspect NAD rates these amps conservatively. It's extremely clean and detailed - I too was pondering getting the A51 at the time (I had an A21 previously) but read some good reviews on the M25 and decided to give it a shot.

As for the fans, about the only way I know they are there is a very slight breeze if I keep my hands over the top cover. Anyway, do give us your thoughts once you've had some time with it!

- Praz

RocketOCannon

Kool,

lol...I was eyeing the same one listed earlier on AG (I think?) Same picture etc...but couldn't pull the trigger. I saw it on eb..and made my mind up and just did it! It's still enroute from seller. As mentioned above...I can't even listen to it yet till I get my preamp etc...so I'm just gonna stare at it like a dog staring at his ball hoping it moves! lol

Congrats on your Parasound A51...sweet amp too. Can't go wrong with either one and I am sue you will love it. The more I read...the more I wanted the NAD...got it..psyched!

I will be sure to take pics as my HT takes shape and I can finally get the rig up and running. If I snagged the A51...I would be just as happy.

enjoy your amp and again good snipe!

truwarrior22

Congrats on the NAD25! Out of all my gear, I'm most proud of it

RocketOCannon

A quick update
Im going with a SVS PB12 Plus sub in place of the Micropro 4000
Anyone have any thoughts, comments opinions on this sub?

EndersShadow

RocketOCannon wrote: »

Anyone have any thoughts, comments opinions on this sub?

SVS is a good company and that sub is pretty kick butt if I remember correctly...

RocketOCannon

Things are getting hotter around here! :>)

Got my Oppo 95 today...pumped!
Nice packaging. Very good looking unit. Need to get the Marantz AV7005 PRE next. Then I can get to use the M25, 707s etc in my bedroom while the basement is constructed starting in July.

Getting closer to placing my big order $ for the TV, speakers, pre and cables soon.

Looking to go with 705s as well. I figured if I need to spend $1,200-$1,500 on (4) 703 speaker stands...I might as well put the $ in to the 705s instead of metal and lead shot/sand. This way I will also get to hear and understand the full LSiM lineup. I can interchange them throughout the system to see where they best fit in with performance strengths.

My plan now is still 5.1 to start
707s - 100% music / Zone2 other side of basement
705s - HT Fronts
703s - HT Rears
706-Center
SUB - SVSPB12

This way I can us the "Full Throttle" 707s on the other side of the basement where it will be 100% music.