Another 770 vs 7100 request

I'm planning on purchasing B&W 703s for the LR, a HTM7 for center, and 4 DS7s for surrounds. Plus a Velodyne subwoofer. For the next few years, it will be a system primarily for movies. Once the kids are gone, I may find time to relax and read. For now, it will primarily be a system for home theater. The room is in a finished basement, L shaped, about 20 deep by 20 wide in the main viewing/listening area with the "L" coming off the back and being about 20 deep by 15 wide.

I want clarity and authority and spectacular special effects. A truly engaging experience. I'm already well down the road in spending more than I anticipated, so I'd like to only buy what I need in terms of an amp. But I don't want to stop a few dollars short after spending a wad on the basement, TV, and speakers.

The B&W specs say 90db at 1 watt. That's pretty sensitive, right? Not too tough of a load?

My current B&K 105wpc drives my M&K satellites + powered subwoofer as loud as I care to listen. Would a 7100 meet my needs? Or should I go ahead pop for the 770?

Thoughts and suggestions most welcome!

The 7100 should do with 100 watts all channels driven.

I have the 7100 with Klipsch but I have to admit the pull for the 770...I have not needed it though.
Bill

Jim: that's a good question for which I'm not so sure that there is a good answer.

Going from 1 watt to 100 watts is 20 dB. Going from 1 watt to 200 watts is 23 dB. You say that your speakers are 90 dB SPL with 1 watt. At 100 watts that would be 110 dB SPL. That is terribly loud. I doubt that you would be listening that loud. Generally, anything over 85 dB SPL is too loud for me. At 200 watts, you would have 113 dB SPL. Would you be able to tell the difference between 110 and 113 dB SPL? I don't know.

If you don't have a sound level meter, I would suggest that you either borrow or buy one and run a few test cases. Radio Shack makes a fairly cheap one for about $40.

Now we get down to the real toughie, will your receiver put out 105 wpc simultaneously to all channels? We have been having a discussion about this subject on another board and the answer, most probably, is NO. Will it put out enough power for your listening experience? Only you can tell.

The outlaw spec for the 7100 says "Power Output (FTC): 7 x 100 watts @ 8 ohms, 20 - 20kHz, 0.05% THD, All Channels Driven."

The outlaw spec for the 770 says "Power output: 200 watts RMS x 7 (all channels driven simultaneously into 8 ohms from 20 Hz to 20 kHz with less than 0.05% total harmonic distortion). 300 watts RMS x 7 @ 4 ohms."

I don't want to be a real nit picker here, BUT, look at the differences. The 7100 DOES NOT say anything about driving a 4 ohm load. Will it? Probably, but they don't say. And, in the 7100 description the word "simultaneously" if left out. Is that significant? I simply don't know. There are a few other spec differences, also. Do they make a difference in your listening experience? I just don't know.

My advice?

Try your setup with your current receiver for a while and see how you like it.

Umm, I don't know what you are looking at but the specs on the Outlaw website CLEARLY state:

Power Output (FTC): 7 x 100 watts @ 8 ohms, 20 - 20kHz, 0.05% THD, All Channels Driven

7 x 165 watts @ 4 ohms, 20 - 20kHz, 0.05% THD, All Channels Driven

Please note both specs are All Channels Driven.

7100 Specs from the Outlaw Website

I'm using the 7100 with an Ascend/HSU 6.1 setup. I will be the first to admit that down deep I wanted the 770 but didn't couldn't justify spending the money for one. Well, after using 7100 for a few weeks no I can honestly say I'm glad I saved the money and went with it. It is all I need in my setup. If I had it to do all over again I would not hesitate to purchase the 7100 again.

warf: my bad on the 4 ohm rating. Got in a hurry. Good catch!!!

But, they omitted the word simultaneously. Was it on purpose?

And, they have "FTC." If that is the Federal Trade Commission, then I think what they are trying to say is that they are only driving 2 of the 7 channels to full power for 5 minutes. At least that is my understanding of the requirement. Maybe someone can comment on what the "FTC" requirements are and how they apply to this amp. Maybe I'll look for a link.

ON the 770, outlaw specifies RMS. That is a good, solid specification.

Now, how does RMS compare to FTC? I'm not sure. It could be an apples to pears comparison.

I'm not trying to bash outlaw or the 7100, I'm just trying to understand the specifications.

Here's a link that starts addressing the issue.
watts

I think that there are some significant differences between the 7100 and the 770.

Yes, I was correct about the FTC being a two channel spec. Here's a link.

FTC

This article gives a better description of what the FTC specs are and how you test them.

FTC Tests

Let's belabor this a little further. Here is the FTC link to changes made in the year 2000.

FTC changes

I find the following most interesting;

"allow the subwoofer and satellite amplifier sections in combination self-powered speaker systems to be driven to full rated power separately, rather than simultaneously, during the power rating tests."

Bottom Line is that I really don't think that your 7100 is rated at 100 watts for all 7 channels simultaneously.

Hope that this helps! I believe that it helped me better understand the outlaw specs.

I have to admit some confusion on this point, since this specifically refers to "combination self-powered speaker systems," which does not apply to anything Outlaw manufactures - they're talking about HTIB systems with separate amps dedicated to distinct and separate parts of the audio spectrum.

In this PDF are some details on this issue, about halfway through the doc. Important is that they distinguish these systems' ratings from standard amp power ratings, because they figure a sub or sat amp in a HTIB system wouldn't necessarily tax the power supply to the detriment of the other amp at peak levels, since unlike stereo amps they each cover different freqs. This refers to the fact that the Amplifier Rule requires testing to be done for both channels of an amp simultaneously, not just one, since one channel will have higher and cleaner output independently (and would be misleading).

To my knowledge, the FTC Amplifier Rule has not been updated specifically for multichanel amps, so "all channels driven" should still mean that all channels are driven with the same test tone simultaneously.

Greg: very interesting!!

Go to page 32 and read what they state about multi-channel amps. My opinion is that only 2 channels MUST be tested simultaneously!!

And, I think this is the key to FTC ratings versus RMS ratings.

I believe that the 7100 specification is consistent with the FTC rule. The reason that the word "simultaneously" is not in the spec is because the 7100 was rated with only 2 of the 7 channels running at full power.

I do not believe that the cost of an amplifier necessarily scales linearly with the power. I think that the primary reason that the 770 costs so much more than the 7100 is that it is more "rugged" to comply with the RMS and "simultaneous" ratings.

The text on p. 32 states the opposite: "the manufacturer’s rated minimum sine wave continuous average power output, in watts, per channel (if the equipment is designed to amplify two or more channels simultaneously) at an impedance of 8 ohms, or, if the amplifier is not designed for an 8-ohm impedance, at the impedance for which the amplifier is primarily designed, measured with all associated channels fully driven to rated per channel power." Subsequent to that, they only exempt HTIB systems from the "all associated channels" rule for the aforementioned "different portions of the audio frequency spectrum."

FTC regulations require that the specifications provided to consumers conform to this. How manufacturers word it (i.e., with or without the word "simultaneously") is irrelevant, because the FTC requires the underlying testing to be the same either way. This prevents companies from doing what you suggest - comparing "apples to oranges" in their power output claims.

greg: Nope, I disagree. Look at the last sentence of the first paragraph on page 33 (I couldn't copy and paste, for some reason). It CLEARLY states that all channels DO NOT have to be driven simultaneously.

You mean this one:

"when measuring maximum per channel output of self-powered combination speaker systems that employ two or more amplifiers dedicated to different portions of the audio frequency spectrum, such as those incorporated into combination subwoofer-satellite speaker systems, only those channels dedicated to the same audio frequency spectrum should be considered associated channels that need be fully driven simultaneously to rated per channel power."

I don't see how you can derive your conclusion from this. What this refers to, "combination subwoofer-satellite speaker systems" and the simultaneous testing of ALL associated sat-only channels separately from sub-only channels, has nothing to do with standalone multichannel amps.

What you say it "clearly states" is neither stated or implied, and must be taken entirely out of its context to infer. If you wish to misinterpret what is made abundantly clear in the document, I don't see a need to discuss further.

that and the fact that the Outlaws "clearly state" it is "All Channels Driven" which is either a lie (I doubt it) or the truth (which I believe) so where do we go from here???
Bill

Ratpack - Thanks for the great info on how watts relate to sound levels. I wasn't aware of the equation.

My browser allows me to see the product pages, but won't let me drill down on the Specs or Gallery or Manual or About sections.

Typically, a higher power amp has a higher damping factor, right? Does the 770 have a higher damping factor than the 7100? And the damping factor is a measure of how well the amp controls cone movement? I'd be happy to look that up myself, but as I said my computer isn't cooperating on the pages within each product description.

What are the differences between the 7100 and 770 besides 100wpc vs 200wpc? Clearly, the "simultaneous" and "all channels driven" discussion is important, but it doesn't look conclusive regarding what Outlaw means with the 7100.

Wharf Rat's comments about wanting the 770 but being happy with the 7100 are MOST helpful. I want the 770 just be sure I get the most out of my gear, but I'd really rather save the money.

Does the 770 do anything more for the sound than just add 3db? That is, does it do a better job of channel separation or cone control or something else? I'd agree that I'm not likely to listen at 110db, much less 113db. But if the 770 is has more immediacy or is more dynamic or other desireable characteristics, I'd love to know about it!

Since I'm building a new system, I'm probably not going to try it with the old system. It would require HUGE effort to pry my B&K out of the current set-up. I'm just going to buy a 7100 or 770 and see what I think. I'd like to make the best choice possible. I'm leaning towards the 7100 to save the $$.

I listened to the B&Ws at ListenUp in Denver through a Rotel pre-amp/amp rated at 100wpc. there seemed to be plenty of volume.

Further info on the diffences between the 7100 and 770 welcome!

Greg: I believe that the following means the front pair, or the center surround pair, or the rear surround pair.

"only those channels dedicated to the same audio frequency spectrum should be considered associated channels that need be fully driven simultaneously to rated per channel power."

One of my links contains this language:

"allow the subwoofer and satellite amplifier sections in combination self-powered speaker systems to be driven to full rated power separately, rather than simultaneously, during the power rating tests.


I don't think that it applies to the rears or subwoofer on a 5.1 system, or side surrounds on a 7.1 all at the same time. The key is the audio that comes out of the sides, rears and subwoofer is not the same audio spectrum. Of course, I guess that you could say that about the audio spectrum that comes from the right and left of each pair.

But, if I have a chance tomorrow, I am going to pose the question to the Outlaw technical support. They should be able to tell us one way or another.

This has been a most interesting dialogue. Thanks!

Bill: where do we go from here?

Well, I'll tell you.

I'll ask Outlaw if all seven channels are simultaneously driven to 100 watts.

That should settle it one way or another.

ratpack, I was going to ask the same thing. Please let us know what you find out.

I did ask this question when I bought mine (it seemed important then) as I looked at the 7100 and the 755 and 770 but I will be interested to hear if they say anything different...interesting read by the way...
Bill

Bill: OK, let's wait and see what they tell me. I'll post my question and what they say.

I look forward to both of our answers.

Thanks.

Ratpack:
Excellent...
Bill

Here is a copy of the questions that I sent Outlaw technical support this morning. I have not yet received a response.

"I have been involved in a very interesting message board discussion about
the ratings of separate amplifiers. The specification of the 7100 cites an
FTC rating. It is my understanding that many audio receiver manufacturers
use the FTC standard as justification for rating/ testing only 2 channels
simultaneously, even though their receivers may have 5 or more channels.

I would like to ask 2 questions.

First, for the 7100, how many channels are rated at 100 watts
simultaneously and simultaneously for what period of time?

Second, for your 770 amplifier, you specify simultaneous RMS power for all
7 channels. There is a perception that since the 7100 is specified with
FTC and the 770 is specified with RMS that there is implied more difference
than just going from 100 to 200 watts. Could you explain why the 2 amps
are specified differently?

A clear explanation would be greatly appreciated.

Thanks!"

The specs for the 7100 list the damping factor as 400. The specs for the 770 list its damping factor as 850. I've been told the damping factor is a measure of how well the amp controls cone movement. Is that true? Does anyone know if a change from 400 to 850 is audible? Is this a valuable spec?

I'm curious as to whether the 770 would sound better than the 7100 at normal listening levels (not ear-bleed levels). 400 vs 850 sounds significant, except that it is possible to have a THD of .00001% and one of .000001% and never hear the difference.

Any thoughts on the damping factor specs?

Any thoughts on the 7100 vs 770 at normal listening levels?

Jim: if you do a web search on damping factor, I think that one of the basic definitions that you will find is load impedance (speaker) divided by source impedance (amplifier). I think that it is just another confusion factor that manufacturers use. I think that the following article describes it fairly well.

damping

That is an excellent web site! Interesting that too high of a damping factor can cause negative feedback. The damping factor of the 7100 is 400; the 770 is 850. Other than watts/channel, that seems to be the one spec that is different. So is 850 better than 400? Apparently, it depends.

A 770 went for $1475 on eBay last night. I was really interested at $1200, kind of interested at $1300, but then lost interest. I think I'm going with a 7100. I don't think I need 200wpc.

I was particularly struck by this quote on that web site: "I can guarantee you one thing: There are an awful lot of people out there spending money on specs they will never be able to hear as differences in the music in a million years. Just don't expect them to ever admit it. I have to really work not to laugh my head off when someone tells me they spent several hundred dollars - or even over a thousand - on speaker cables and they "sound better" than a nice heavy gauge twisted pair of stranded copper wires they could have had for about five bucks... "

The sales guy I'm talking to about a TV and speakers is really pushing me to buy exotic speaker wire. I auditioned speaker wire and interconnects about 10 years ago. I did a double-blind test with both. I heard a difference in interconnects - very slight, very subtle, but very consistent. I never heard any difference in speaker wire. It was only the $15/foot stuff, nothing really exotic, but I could not detect a difference between that stuff and lamp cord.

So I think I'll get the B&Ws, Outlaw 990/7100, some decent interconnects, and basic speaker wire.

That sounds like a really good plan, Jim. A coworker of mine has B&W 805's (smaller than the 703's you're looking at, but also 2dB less efficient and run full range since he has no sub) that he drives with a 120W Rotel amp very successfully. I think the 7100 will serve you well.

Well folks, I still DO NOT have an answer to my questions from Outlaw technical support.

I'll give it another couple of days, they could be very busy doing other things.

Jim: anyone who tells you that speaker wires are not fully characterized by their RLC parameters, JUST DOESN'T KNOW WHAT THEY ARE TALKING ABOUT!!

You have a good plan!

curiouser and curiouser, Alice...
Bill

Hmmmm......

I am SURE they will respond! C'mon guys...let's hear it!
Bill

Hey folks, here is the response. I'd say that it is MOST interesting!!!!!!!!!!

"Hello Fellow Audiophile,

Sorry for the slow response, there was a little confusion on our end because the web site contained an error. Before responding I needed to be absolutely clear that the information I intended to provide to you was correct.

The Model 7100 rating is not an FTC rating, it is RMS just like the Model 770. In fact, all of our products use the older RMS style of rating which is all channels driven at full power. Thanks for catching this and pointing it out. We will correct the information on the web site right away.

Thanks and regards,

Scott"

I just checked their 7100 product specifications and they have been changed to reflect RMS.

GREAT job board!!!!!!!!!!!!!!

Nice..... Good job rat and company...

Gonk: RMS ratings are SO MUCH better than FTC that I am surprised that no one caught this or asked the question before.

But, it is a most interesting development. With the revised spec, that 7100 is a GREAT deal at Outlaws price!!!! No doubt about it.

rat,
No one caught it 'cuz you were meant to...you da man!
Bill

silver(Bill): when you were going through the trades, what were your consideratings (other than price) between the 7100, 755 and 770?

I belong to the more power club...I thought that if 100 WPC of Outlaw power is good...200 WPC should be great!
Secondly, I will probably only use 5.1 so I was not too keen about buying 7.1 and having 2 channels unused...but since, as always for me, I bought in one fell swoop...buying my Klipsch AND the 950 AND the 7100 AND the LFM-1 sub...well, I couldn't convince myself I "needed" the 755 or 770...I have not been disappointed except for "bench racing."
Bill

I went with the 770 as well, and will jump to the 790 as well...unlimited (well 300w) pooooooooowwwweeeeeeeerrrr!!

There are 2 things to consider. The 7100 will play louder than you can tolerate in your room.
You said in your opening post “I want clarity and authority and spectacular special effects.” An
important part of the special effects comes from having a system that is able to play a sound track
or music without clipping off any of the loud passages (transients). For instance, the gunshots in
“Open Range”, which can be spectacular on a good system. It takes a lot of amplifier power to
be able to do this. The 770 would be better than the 7100. The 790 would not be too much, even
on speakers of 90dB efficiency. Only you can decide how much the special effects are worth to
you. I have a 7100 driving Rocket RS1000s (rated @ 90.5dB), an RSC200, and RS250s with an
SVS PB2+. The gunshots from “Open Range” hit me in the chest in a very dramatic fashion. I
have to believe that they would sound even better with a 770 and better yet with a 790.